International Conference & Expo on
Advances in Power Generation from Renewable Energy Sources (APGRES-2017) December 22-23, 2017
Government Engineering College Banswara Behind Mayur Mill, Dungarpur Road Banswara-327001
International Conference & Expo on
Advances in Power Generation from Renewable Energy Sources (APGRES-2017) December 22-23, 2017
ISBN-978-81-932091-2-7
GOVERNMENT ENGINEERING COLLEGE BANSWARA Behind Mayur Mill, Dungarpur Road Banswara-327001
INNOVATIVE RESEARCH PUBLICATION
APGRES-2017 Editorial Board Mr. Ankur Kulshreshtha, GEC Banswara Mr. Sohan Lal Swami, GEC Banswara Mr. Shailendra Goswami, GEC Banswara Mr. Ravi P. Maheshvari, GEC Banswara Ms. Shulbha Kothari, GEC Banswara Mr. Himanshu Swarnkar, GEC Banswara Dr. Shiv Lal, GEC, Banswara
i
APGRES-2017 Committees Honored Chair: Prof. S. C. Kaushik, CES, IIT Delhi, India Chief Patron: Honorable Smt. Kiran Maheshwari Higher and Technical Education Minister, Govt. of Rajasthan Patron: Dr. Shiv Lal, Principal, GEC, Banswara Convener Dr. N. L. Panwar, CTAE Udaipur Mr. Gaurav Pathak, GEC Banswara Coordinators: Mr. Ankur Kulshreshtha/Mr. Sohan Lal Swami, GEC Banswara Advisory Committee: Prof. B. V. Reddy, Univ. of Ontario, Canada Prof. L.M Das, CES IIT Delhi, India Prof. S. A. Sherif, Univ. of Florida, U.S.A. Prof. P. K. Jamwal, Nazarbayev Univ. Astana Prof. K. S. Ong, Monash University, Malaysia Prof. M. Maerefat, Tarbiat Modares Univ., Tehran, Iran Prof. Mohammad O. Hamdan, United Arab Emirates University.UAE Prof. Atit Koonsrisuk, Suranaree University of Technology, Thailand Prof. Abdul Khaliq, King Fahd Univ. of Petroleum and minerals, Saudi Arabia Prof. Richard Petela, Technology Scientific Ltd., Canada Prof. N. S. Rathor, ADG, ICAR Delhi India ii
Prof. S. Mishra, UCE RTU Kota, India Prof. A. K. Pratihar, GPU Uttarakhand, India Prof. H. Hirani, MED IIT Delhi, India Prof. Paramjeet Singh, GDEC, PTU, India Prof. S. L. Soni, MNIT, Jaipur, India Prof. M.K. Gupta, UEC, Ujjain, India Prof. Sunil Punjabi, UEC, Ujjain, India Prof. S. Chandrasekaran, DOE, IIT Chennai Prof. J. K. Nayak, ESE IIT Bombay Dr. Henry Tan, Univ. of Aberdeen, Scotland, UK Dr. P.K. Bhargava, CBRI Roorkee, India Dr. V Shiva Reddy, SPRERI Anand, India Dr. Harender, SNU Greater Noida, India Dr. Navneet Kumar, Galgotia Univ. Gr. Noida, India Dr. Rajat Bhagwat, MBM, JNVU Jodhpur Dr. Raj Kumar, YMCA Faridabad, India Dr. Rahul Dev, MNNIT Allahabad, India Dr. Akhilesh Arora, DTU Delhi, India Dr. Amit Sharma, DCRUST, Murthal, India Dr. Vishal Garg, IIIT Hayderabad, India Dr. Rohit Mishra, GEC Ajmer, India Dr. V. Bansal, UCE, RTU Kota, India Dr. K.N. Patil, SDMCET Dharwad, India Dr. Ashok Sharma, GASCO Abu Dhabi Dr. Rahul Rawat, MNRE Delhi India Mr. Radheshyam Meena, MNRE Delhi India Dr. M. L. Meena, MNIT Jaipur Dr. Mukesh Kumar, MNIT Jaipur Dr. S.K. Singh, SEC, MNRE, India Dr. Sanjay Kumar, CEL, Sahibabad, U.P. India Dr. K. Vamsi Krishna, CES IIT Delhi ******* iii
CONTENTS i ii
Editors Board Committees
S. No.
Title
1.
3-7
6.
Cascade Utilization of Energy and Exergy for the Performance Analysis of a Solar Powered Cogeneration Cycle Modeling, simulation and performance analysis of monocrystalline and polycrystalline panel. Voltage and frequency controller for three Phase Four Wire Hybrid System for Loads in Isolation Effect of Heat Transfer Fluids on the Techno-Economic Performance of Parabolic Trough based Solar Thermal Power Generation in India Determination of optimum heat rejection pressure in transcritical N2O refrigeration cycle with vortex tube Impact of Renewable Energy Generation on Bidding Strategy
7.
Review of Different Energy Resources
37-40
8.
IA Review of CFD Methodology used for Solar Devices
41-45
9.
Impact of RES in Distribution Systems
46-48
10.
Microbial pretreated Water hyacinth as an Energy Source
49-55
11.
Effect of Viscosity in Biomechanics for the Fluid: A Review
56-58
12. 13.
Thermodynamic investigation on biomass derived syngas fueled 59-63 combined cycle power plant Bio Fuel: Need for the sustainable Generation 64-69
14.
Parametric study of Pump as Turbine-1: variation of speed
70-75
15.
Performance Analysis of a Low Price Thermoelectric Cooler: An Experimental Approach Transcritical CO2 Based Dedicated Mechanical Sub Cooling VCR System: A Review Pump as Turbine: Review of Simple Modifications for Performance Improvement Growth, Design Aspects and Applications of Photovoltaic Systems
76-82
2. 3. 4. 5.
16. 17. 18. 19. 20. 21.
Page No. 8-11 12-18 19-24 25-33 34-36
83-88 89-94 95-101
An Assessment of Wind Power Potential in Astana: A Wind Power 102-111 Plant Feasibility Study for Akmola Region, Kazakhstan Energy efficiency of PV panels under real outdoor conditions – An 112-119 experimental assessment in Kazakhstan Design and Performance Evaluation of Improved Biogas Stove 120-126 (IBS) by Preheating of Biogas
22.
127-133
26.
Empowering Rural Women through Renewable Energy Technologies An Expert System for the Estimation of Direct Solar Radiation in Indian Region Parametric study of Pump as Turbine-2: Variation of Diameter of Impeller Renew your Inner Energy through Human Internal Energy Sources: A Practitioner and Theoretical Approach Renewable Energy Management for Smart Cities of India
27.
Design Aspects of Small Scale Wind Turbines: A Review
156-161
28.
On-Off Control Based Maximum Power Point Tracking of Wind 161-168 Turbine Equipped by DFIG Connected to the Grid Advances in Green Composites: A Review 169-170
23. 24. 25.
29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45.
134-137 138-142 143-150 151-155
Nonlinear coupling of Inertial AlfvĂŠn waves and cavity formation in 171-175 low beta plasmas Thermodynamic analysis of Factors affecting the Performance of 176-181 Solar Collectors Reactive power control in distribution line by using D-STATCOM 181=186 State of Health Assessment of Lead Acid Cells as a Function of 187-192 Conductance Control of Current and Voltage for Micro Grid 193-197 Reactive Power Compensation using Static Synchronous Series 198-201 Compensator (SSSC): A Review Paper Induction Motor Protection System Using Fuzzy Logic 202-206 A Review Paper on Fuzzy Logic Based Speed Control of Induction 207-210 Motor Renewable Energy Resources with Internet of Things 211-214 Renewable Energy Options and Possibilities to develop Banswara as Energy Hub: A theoretical approach Design Analysis of Distribution Power Network in ETAP-A Case Study Power system stability enhancement using fuzzy logic-based power system stabilizer Impact of Facts Device on Protective Distance Relay
215-224 225-229 230-234 235-239
Study and Review of Design and Simulation of CCM Boost 240-244 Converter for Power Factor Correction Using Variable Duty Cycle Control Dynamic Voltage Restorer for Power Quality Improvement 245-248 Design of Active Shunt Filter for Harmonics Reduction at Load 249-253 Side for Power Quality Improvement
46.
A Study on Speed Control of BLDC Motor Using Fuzzy Logic
47.
Hybrid Energy Management System design with Renewable Energy 258-262 Sources (Fuel Cells, PV Cells and Wind Energy): A Review Comparative study of ATSMC and PTMC for a Single Phase SAPF 263-268
48. 49. 50. 51. 52. 53. 54. 55. 56. 57. 58. 59. 60. 61. 62. 63. 64. 65.
254-257
Combined Vector and Direct Power Control of Doubly Fed Induction Generator- Based Wind Turbines: A Review Paper Biomass-Diesel based Hybrid Electrical Supply System for Small Network Energy Conservation Options to Transport Solids at Higher Concentration Analysis of Process Characteristics for a Batch Production Unit and Controlling the Variation for Effective Performances Availability Analysis of Energy of Micro Hydro Power Plant with Screw Archimedean Turbine in Indian Context Solar Energy in India and National Solar Mission: A Review
269-273
Optimization Techniques Based Selective Harmonic Elimination for Multilevel Inverter with Reduced Number of Switches Techno-economic Analysis of Solar Photovoltaic Cooling System: an analysis in four different climates in India Effect of Renewable Energy on Green House Effect and Environment: A Study Fault Ride-Through Techniques of Wind Turbine State of Art: A Review Numerical solution to Natural convection in Triangular enclosures and its application for double dome solar water distillation systems Solar Parks to Ramp up Solar Projects in the Country, Issues and Challenges: Contribution towards Climate Change Interconnected Hybrid RE Network with Embedded VSC - MTDC Transmission System for Secure and Efficient Power Delivery: Modeling and Steady State Response Analysis Mitigation of Inrush Current in Power Transformer using Prefluxing Technique Analysis of Solar Thermal Cooling System Using TRANSOL
312-319
274-284 285-290 291-298 299-305 306-311
320-325 326-331 332-338 339-345 346-359 360-377 378-384 385-388
Analysis and Modeling of AC-DC Buck Converter Using PFC 389-395 Control Technique Architectural and Technical Approach for Self-Sustainable 396-401 Building
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)” December 22-23, 2017 at GEC Banswara, www.apgres.in
ISBN-978-81-932091-2-7
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)” December 22-23, 2017 at GEC Banswara, www.apgres.in
Short note for Conference
Apparently, the climate change is inextricably linked to future energy and necessitates a concerted worldwide focus on the development and implementation of sustainable energy solutions. In the coming decades, the energy sector will face an increasingly complex array of interlocking challenges encompassing economic, geopolitical, technological, and environmental sectors. Since the developing world’s population continues to expand, the energy needs of billions of additional people in rural and especially urban areas will have to be met. Moreover, supplies of conventional oil and conventional natural gas are expected to decline. Use of conventional energy resources, including coal, will also have to be scrutinized since increasingly tight limits are being placed on the total amount of greenhouse gases that can be released into the atmosphere. Eventually, solution to all our energy related problems lies in the development of alternative energy sources and technologies. The responses to this varied range of developments will play a crucial role in shaping trade and investment flows, competitive positions, and the structure of economies across the globe, while simultaneously determining mankind’s capacity to construct a sustainable future. Meeting these challenges will require very long lead times. The objectives, in the context of future energy, therefore are, renewing the existing patterns of energy production and consumption, transport and other technical infrastructures, the layout of cities, the nature of the industrial capital stock, current technologies, values and attitudes, etc. I hope that the APGRES2017 conference shall lead the discussion in order to advance a global green energy transition. Deliberations during the conference shall promote dialogues, innovation and the international transfer of knowledge between stakeholders in civil, commercial, institutional and government sectors. The conference will demonstrate ideas and solutions on energy recycling sources and implementation of the principle "green economy" buildings, that generate energy for selfprovision, "smart houses", electric cars, automobiles on bio fuel and others. Dr. Prashant Jamwal Department of Electrical and Electronics Engineering, School of Engineering, Nazarbayev University, Astana, Kazakhstan ISBN-978-81-932091-2-7
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)� December 22-23, 2017 at GEC Banswara, www.apgres.in
Cascade Utilization of Energy and Exergy for the Performance Analysis of a Solar Powered Cogeneration Cycle 1
Abdul Khaliq1*, Faizan Khalid2, Suhail A. Siddiaqui3 Mechanical Engg. Dept., King Fahd University of Petroleum and Minerals (KFUPM) Dhahran - 31261, Saudi Arabia, 2 Department of Mechanical Engineering, Gautam Buddha University, Greater Noida, U.P, India 3 Mechanical Engineering Department, Al-Falah School of Engg. & Tech., Dhauj, Faridabad, Haryana, Corresponding Author: khaliqsb@gmail.com
Abstract Present study focuses on the first and second law analyses of a solar based cogeneration system which could simultaneously produce the electric power and refrigeration. An investigation is carried out to ascertain the effect of varying the direct normal irradiation (DNI) and turbine back pressure on the first law efficiency, cooling to power ratio and second law efficiency of the cogeneration system. The results obtained indicate that variation in DNI and turbine back pressure have a considerable impact on the second law performance of the cogeneration system while its first law performance is least affected. Nomenclature E Rate of exergy [W] Q Rate of heat transfer [W] W Rate of work output [W] R / Cooling to power ratio q Solar radiation received per unit area [W/m2] Subscript s Sun R Refrigeration El Electrical c/p Cooling to power ex exergy
1. Introduction In order to utilize the solar thermal energy for its potential in reducing fossil fuel consumption and alleviating environmental problems, the cogeneration cycles for combined production power and cooling have been explored for improving the overall energy conversion efficiency. In this context, a new combined power and cooling thermodynamic cycle was proposed by Goswami [2002]. This was a combined cycle because it produces both power and cooling simultaneously with only one heat source, using ammonia-water mixture as the working fluid. Other researchers [Dai et al.(2009), Khaliq et al.(2012), Zhang and Li ( )] have also investigated this new cycle from both energy and exergy point of view where latter provides a clearer assessment of various losses occurring in energy systems both
quantitatively and qualitatively and thereby shows the possibilities where improvements in efficiency could be made. Hasan et al [ ] presented the first and second law analysis of the combined power and cooling cycle that could use low temperature heat sources below 200oC as a primary energy input and ammonia-water mixture as a working fluid. Li et al (2013) investigated the organic Rankine cycle with ejector from first and second law point of view and emphasized on its thermo-organic performance at the maximum net power output of the cycle. Habibzadeh (2013) conducted a thermodynamic study on organic Rankine cycle with ejector and evaluated its first and second law performance for different working fluids. They obtained the optimum values of the turbine and pump inlet pressures which minimize the total thermal conductance of the system for working fluids under consideration. From the foregoing literature review, it is noted that the majority of the previous research is focused on the solar assisted cogeneration cycle which combines the organic Rankine cycle with an ejector and utilized R-134a, R-113, R-123, R141b, R117, and R-609 etc. as the working fluids which have the advantages of zero ozone depletion potential, but they have higher global warming potential and safety problems as well as they produces lower power output because of their smaller latent heat of vaporization. In order to overcome ISBN-978-81-932091-2-7
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)� December 22-23, 2017 at GEC Banswara, www.apgres.in
with the aforementioned disadvantages, a new cogeneration cycle was introduced which combines the conventional Rankine power cycle with a steam ejector. This cycle used extraction steam from steam turbine in conventional Rankine cycle to heat the working fluid of the steam ejector refrigeration cycle. Since water is used as a working fluid for both power and cooling production which has a zero-ozone depletion potential and zero global warming potential as well as have very good thermal properties, therefore, this cycle could be considered as one of the most suitable options for harnessing the solar thermal potential of the hot areas. The performance characteristics of solar based cogeneration cycle using the solar power tower technology are not well reported in the literature. Therefore, the objective of the present work is to investigate the performance of a proposed cogeneration cycle using a combined first and second law approach. A parametric analysis is performed to examine the effects of some influencing parameters on the energy and exergy efficiency of the cogeneration cycle. Numerical results are graphed and commented upon.
2. Theoretical Analysis Energy and exergy analyses of a solar powered cogeneration system involve the application of the principle of conservation of mass and conservation of energy along with the second law of thermodynamics and can identifies and quantifies the sources of losses and hence provides guidance for performance improvement. The relevant parameters required to evaluate the energetic and exergetic performance of the proposed cogeneration cycle may be considered as follows:
2.1 Energy Utilization Factor (EUF) The energy utilization factor is the energy measure of efficiency and is simply a ratio of useful output energy to input energy. For cogeneration of electrical power and cooling the energy utilization factor can be defined as the ratio of all the useful energy extracted from the system to the primary
energy input to the cycle, and may be expressed as: ̇ ̇
EUF =
=
̇
̇ ̇ ̇
where, �̇ is the rate of thermal energy received by the heliostat and may be given as �̇
=đ??´ đ?‘ž
2.2 Cooling to power ratio đ??‘ đ??‚/đ?‘ˇ The effectiveness of the proposed cogeneration system is directly related to the amount of power it can generate for a given amount of refrigeration produced. Therefore, R / which is the cooling to power ratio could be one of the important parameter to assess the thermodynamic performance of a given cogeneration system. It is defined as: R
=
/
̇ ̇
In both energy utilization efficiency and power to cold ratio, power and refrigeration are treated as equal from the first-law of thermodynamic point of view. This reflects that parameters based on first-law are concerned with the quantity of energy, not its quality. Thus, EUF and R / are also known as first-law efficiencies. 2.3 Exergy efficiency ď ¨đ??žđ??ą : Exergy, or availability, which deals with the quality of energy along with its quantity, can be defined as the maximum amount of work produced during the reversible transition of a stream of a matter from its given thermodynamic state to its dead state where it is supposed to be in thermodynamic equilibrium with the environment. Exergy efficiency is the exergy output divided by the exergy input to the cycle. It may be further defined as:
ď ¨
=
̇
̇ ̇
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)� December 22-23, 2017 at GEC Banswara, www.apgres.in
where, đ?‘ŠĚ‡ is the exergy of electrical power output and may be given as đ?‘ŠĚ‡ = ď ¨ đ?‘ŠĚ‡ where, đ?‘ŠĚ‡ is the exergy of electrical power output đ??¸Ě‡ is the exergy associated with the rate of refrigeration produced, and đ?‘„̇ is the rate of exergy associated with the solar radiations falling on heliostat field and may be given as đ??¸Ě‡
− đ?‘„̇
1−
where đ?‘‡ is the apparent Sun temperature which may be taken as 4500 K. đ??¸Ě‡ = đ?‘„̇
đ?‘‡ −đ?‘‡ đ?‘‡
It is defined as the refrigerator capacity divided by the COP of a Carnot refrigeration cycle operating between đ?‘‡ − đ?‘‡ . 3.
Results and Discussion
The effects of DNI and turbine back pressure is observed on the energyic and exergetic performance of the proposed solar based cogeneration. Numerical results are graphed and comment upon and may be reported below. The effect of change in DNI on first law efficiency and cooling to power ratio of the cogeneration is shown in fig. 2. It is observed that the first law efficiency increases with the increase in DNI while cooling to power ration decreases insignificantly with the increase in DNI. This is because higher DNI causes a greater turbine output and hence a higher efficiency. Increase in turbine output is greater than the increase in cooling output, therefore, the cooling to power ratio increases marginally with the increase in DNI. In order to gain further insight into the performance of the system, the effect of DNI is also observed on the second law efficiency and the exergetic cooling to power ratio of the cogeneration which is shown in fig. 3. Both second law efficiency and the exergetic cooling to power ratio were found to be increased considerably with the increase in
DNI. This is because increase in DNI as a higher temperature source causes a greater exergy output of the system. It is further noticed that amount of exergy associated with the cooling capacity is considerably less than the energy and turbine power output gives 100%contribution to exergy, therefore, the exergetic cooling to power ration also a considerable increasing trend parallel to second law efficiency. The effect of change in turbine back pressure is also investigated and is shown in fig. 4. It is found that both first law efficiency and cooling to power ration of the cogeneration are significantly increased with the increase in turbine back pressure. This is due to the fact that as turbine back pressure increases, the pressure ratio across the turbine decreases which decreases the turbine power, but there is an increase in motive steam pressure which Environment Temperature(0C) 270C Turbine inlet pressure (MPa) 8 Molten salt outlet temperature 567-644 range (0C) Molten salt inlet temperature 290 0 ( C) Area of the heliostat, AH ( m2) 10000 Turbine isentropic efficiency 85 (%) Generated efficiency (%) 95 0 Evaporator temperature, TE ( C) 7 increases the refrigeration capacity. Since the increase in refrigeration capacity is greater than the decrease in turbine power output, therefore, both first law efficiency and cooling to power ratio are increased considerably with the increase in turbine back pressure. The second law efficiency and the exergetic cooling to power ratio shows the opposite trend with the increase in turbine back pressure. This is because the turbine power output which gives 100% contribution to exergy decreases while the exergy of the refrigeration which is much less than the refrigeration capacity decreases with the increase in turbine back pressure. Therefore, exergy output which is the sum of turbine power and the exergy of the refrigeration ISBN-978-81-932091-2-7
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)” December 22-23, 2017 at GEC Banswara, www.apgres.in
decreases while exergetic cooling to power ratio increases. ηII (%), Cooling to Power ratio
ηI (%), Cooling To Power Ratio
35 30 25 First Law Efficiency [%] 20
Cooling to Power ratio
15
15
10
5
Second Law Efficiency [%] Cooling to Power ratio
0 0.3
10
0.325
0.35
0.375
0.4
0.425
0.45
0.475
Turbine Back Pressure (MPa)
Figure 5
5 0 800
825
850
875 900 DNI (W/m2)
925
950
975
Figure 2 20 18 ηII (%), Cooling to Power ratio
20
16 14 12 10
Second Law Efficiency [%]
8
Cooling to Power ratio
6 4 2 0 800
825
850
875
900
925
950
975
DNI (W/m2)
Figure 3
Conclusion In this paper, an analysis based on combined first and second laws of thermodynamic was performed for the solar based cogeneration system which could produce both power and cooling simultaneously. It was found that by employing an ejector between the turbine and condenser, thermodynamic performance of the system increased. Results obtained after the parametric investigation show that the variation in DNI and the turbine back pressure have a greater impact on the second law performance of the cogeneration than its first law performance. It is noted that second law analysis provides an insight into the system performance which first law analysis alone cannot. The model presented for the analysis in this paper can be used to assess the thermodynamic performance of other kind of cogeneration system. ACKNOWLEDGEMENT
ηI (%), Cooling to Power ratio
35
The first author would like to acknowledge the financial support provided through the Project No. RG1330 under the Grant of Research Group from DSR of King Fahd University of Petroleum and Minerals, Saudi Arabia.
30 25
First Law Efficiency [%] Cooling to Power ratio
20 15 10 5 0 0.3
0.325
0.35
0.375
0.4
0.425
Turbine Back Pressure (MPa)
Figure 4
0.45
0.475
REFERENCES [1] Xu F., Goswami D. Y., and Bhagwa S. S., A combined power/cooling cycle. Energy, 25 (3), 2002, pp. 233-246. [2] Dia Y., Wang J., and Gao L., Exergy analysis, parametric analysis and optimization for a novel combined power and ISBN-978-81-932091-2-7
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)” December 22-23, 2017 at GEC Banswara, www.apgres.in
ejector refrigeration cycle. Applied Thermal engg. 29, 2009, pp. 1983-1990. [3] Khaliq A., Agrawal B., and Kumar R., First and second law investigation of waste heat based on combined power and ejector– absorption refrigeration cycle. International Journal of Refrigeration, 35, 2012, pp. 88-97. [4] Zhang N., and Lior N., Development of novel combined absorption cycle for power generation and refrigeration. ASME Trans. Energy Resources Technology, 129, 2007, pp. 254-265. [5] Hasan A. A., Goswami D. Y., and Vijayaraghavan S., First and second law analysis of a new power and refrigeration thermodynamic cycle using solar heat source. Solar Energy, 73 (5), 2002, pp. 385-393. [6] Xinguo L., Xiajie L., and Zhang Q., The first and second law analysis on an organic Rankine cycle with ejector, Solar Energy, 93, 2013, pp. 100-108. [7] Habibzadeh A., Rashidi M. M., and Galanis N., Analysis of combined power and ejector-refrigeration cycle using low temperature heat, Energy Conversion and Management, 65, 2013, pp. 381-391. [8] Bejan A., Fundamentals of exergy analysis, entropy generation minimization, and the generation of flow architecture, International Journal of Energy Research, 26, 2002, pp. 545-565. [9] Xu C., Wang Z., Li X., and Sun F., Energy and exergy analysis of solar power tower plants. Applied Thermal Engineering, 31, 2011, 3904-3913.
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Modeling, simulation and performance analysis of monocrystalline and polycrystalline panel. Neelam Rathore, N.L. Panwar, Surendra Kothari, Kirtika Sharma Renewable Energy Engineering Department, M.P.U.A.T, Udaipur, India Corresponding Author: E-mail: neelamrathore79@gmail.com ABSTRACT This paper presents the modeling and simulation of photovoltaic model using MATLAB/Simulink software package. Modeling and simulation is done for monocrystalline panel and polycrystalline panel of 40 Watt having total 37 cells in which 36 cells were connected in series and 1 cell in parallel. For both type of panels electrical characteristics is plotted and temperature effect is analyzed. Performance analysis of mono-crystalline and poly-crystalline solar photovoltaic panels was done considering certain parameters i.e. analysis of V-I curve, effect of variation in tilt angle on PV module power, effect of shading on PV module power, effect of increase of temperature on PV module power, efficiency, space efficiency and cost. Both the panels were compared on the basis of above parameters. The proposed model is very useful for engineers who are dealing with PV system designing. 1. INTRODUCTION Photovoltaic (PV) is a method of generating electrical power by converting solar radiation into direct current electricity using semiconductor by photovoltaic effect. The modeling and simulation of photovoltaic (PV) have made a great transition and form an important part of power generation in this present era [1]. The cost and the performance of PV plants strongly depend on the modules. The ideal photovoltaic module consists of a single diode connected in parallel with a light generated current source (ISC) as shown in Figure 1 [1-2]:
Following equations were written in MATLAB for the figure shown above Fig 1: The ideal photovoltaic module consists of a single diode connected in parallel with a light generated current source (ISC) as shown in Fig 1: I = ISC -I RS Where ISC is photocurrent which is the lightgenerated current at the STP condition (25°C and 1000W/m2). The equations of Reverse Saturation Current and photocurrent are given by [3 -4]: I RS=Iscref[e ( ] ISC =[ Iscref+ K (T
Tref)]
The equation that describes the I-V characteristic of the circuit in Fig1 is given by ISC – ID –VD / RP - IPV = 0 Output of PV Module: It represents the output current generated which depends on the PV module voltage, solar irradiance on PV module, wind speed, and ambient temperature. [4 -5] Fig 1: Solar cell model using single diode with RS 2.
MATHEMATICAL MODELLING
IPV = NPISC - NSIO{ exp (q(VPV + IPV RS)/ NSAKT) - 1} - VPV + (IPV RS / RP) Where k is the Boltzmann constant (1.38 x 10 ^ -23 J K-1), q is the electronic charge (1.602 x 10 ^ -19 C), T is the cell temperature (K), A is ISBN-978-81-932091-2-7
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)” December 22-23, 2017 at GEC Banswara, www.apgres.in
the diode ideality factor, the series resistance R S (Ω) and is the shunt resistance RP (Ω). NS is the number of cells connected in series = 36. Np is the number of cells connected in parallel and VOC = V PV. Theoretically observations were recorded using MATLAB and practically characteristics were plotted using “Solar PV Training and Research Kit” shown in fig 2. Circuit diagram to analyze V-I Characteristics is shown in figure3.
varying irradiance at 25° C panel)
( Monocrystalline
Fig 6:MATLAB P-I characteristics for Varying Irradiance at 25° C (Mono Panels) Fig 2: Circuit diagram to analyze V-I characteristics 3. RESULTS AND DISCUSSION 3.1 V-I CHARACTERISTICS V-I and P-I characteristics at 25˚C for both types of panel were observed so that power can be observed at any radiation using MATLAB as shown in below figure 3 and 4. Fig 7:MATLAB P-I characteristics for varying Irradiance at 25° C (Mono Panels) Irradiance at 25 ° C (Poly Panels)
Fig 3: MATLAB V-I characteristic for varying irradiance at 25° C ( polycrystalline panel)
Fig 3: MATLAB V-I characteristic forfor
As it can be seen from graphs, at constant module temperature, it can be observed that with increase of solar irradiance, the shortcircuit current and open circuit voltage increases. Therefore, higher the irradiation, greater is the current. Contrary to the influence of the solar irradiance, the increase in the temperature around the solar module has a negative impact on the power generation capability. Table 1 shows that as temperature increases power decreases but the decrement of power is more for monocrystalline panel as compared to polycrystalline panel. Another parameter that gets affected is open circuit voltage. As temperature increases open circuit voltage decreases while short circuit current does not very much. Table 1: Effect of variation of temperature on power (MATLAB results) Temper
Open Circuit voltage
Power(watt) ISBN-978-81-932091-2-7
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)” December 22-23, 2017 at GEC Banswara, www.apgres.in ature
(Volt) Polycryst alline Panel
Monocrys talline Panel
Polycryst alline Panel
Monocrys talline Panel
25° C
22
22
37
39
50° C
21
17
35
28
75° C
19
15
31
24
3.2 EXPERIMENTAL ANALYSIS (using “Solar PV Training and Research Kit”) 3.2.1 Effect of increase of temperature on PV module power Fig 7 is showing effect of increase of temperature on PV module power for monocrystalline and polycrystalline PV panel. Here temperature is operating temperature of solar panel which is always 25˚C greater than ambient temperature. As temperature increases power decreases but the decrement of power is slightly lower for polycrystalline panel as compared to monocrystalline panel.
Fig 9: Comparison Curve of temperature on PV panels 3.2.2 Effect of shading on PV Module power Readings were taken for 0 cell shading, 2 cell shading, 4 cell shading, 9 cell shading and power was observed at different shading. In case of shading power decrement of 23.9% was observed in polycrystalline while only 19.37% of power was reduced in monocrystalline panel. Monocrystalline panel is less affected by shading and works well in shady condition as compared to polycrystalline panel as power drop was more in case of polycrystalline panel during shading as shown fig 8. Efficiency: Power was observed for full day ( i.e. 7 a.m. to 5 p.m.) hence efficiency was calculated . Efficiency of monocrystalline varies between 3% to 14% whereas from polycrystalline panel it is 2.5% to 9.5%.
Fig 8: Curve showing effect of increase showing effect of shading for both panels
3.2.3 Space Efficiency: As two panels were considered while taking observations for different parameters and the area of monocrystalline panel was 0.18 m2 ISBN-978-81-932091-2-7
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while for that of polycrystalline panel was 0.20 m2 for 40 watts. Monocrystalline panel occupies small space as compared to polycrystalline panel for the same amount of power. Monocrystalline panels supply power about 222 Watt/m2 while polycrystalline supplies power about 200 watt/m2. 3.2.4 Cost: Now a days cost of both panels is decreasing. Monocrystalline solar panels are expensive because of its purity. Polycrystalline cells are made up of multiple crystals and are generally less expensive to manufacture than mono cells. 4.
CONCLUSIONS Power output from monocrystalline panel is more than polycrystalline so Monocrystalline panel tends to perform better than similarly rated polycrystalline at low light conditions. Theoretically and Practically “Effect of increase of temperature on PV module power was observed and it was concluded as temperature increases power decreases but the decrement of power is slightly lower for polycrystalline panel as compared to Monocrystalline panel. When temperature was increased from 25°C to 50°C power decreases by 5.40 % in case of polycrystalline while in case of monocrystalline power decrement of 28.20 % was observed. Effect of shading on PV Module power was done and it was observed that monocrystalline panel is less affected by shading and works better in shady condition as compared to polycrystalline panel. In case of shading power decrement of 23.9% was observed in polycrystalline while only 19.37% of power was reduced in monocrystalline panel Both monocrystalline and polycrystalline panels are good choices but polycrystalline panel tends to be less space efficient as Monocrystalline panel occupies small space as compared to polycrystalline panel for the same amount of power.
REFERENCES 1. Abdulkadir, M., Samosir, A.S. and Yatim, A.H. M. 2012. Modeling and Simulation Based Approach of Photovoltaic System in Simulink Model, ARPN Journal of Engineering and Applied Sciences, Vol. 7: 616-623. 2. Adamo,F., Attivissimo, F., Nisio,A.D., Lanzolla, A.M.L. and Spadavecchia, M. September 6−11, 2009. Parameters Estimation for A Model of Photovoltaic Panels, XIX I MEKO World Congress Fundamental and Applied Metrolog: 964-967. 3. Basim Alsayid . 2012. Modeling and Simulation of Photovoltaic Cell/Module/Array with TwoDiode Model, International Journal of Computer Technology and Electronics Engineering, Vol. 1, Issue 3: 6-11. 4. Bikaneria,J. Joshi,S.P. and Joshi, A.R. 2013. Modeling and Simulation of PV Cell Using One Diode Model, International Journal of Scientific and Research Publications, Vol. 3, Issue 10: 1-4. 5. Chouder, A ., Silvestre,S., Taghezouit ,B. and Engin Karatepe . 2012. Monitoring, modeling and simulation of PV systems using LabVIEW, Solar Energy ,1-12. 6. Das, D. and Pradhan, S.K. 2011. Modeling and simulation of PV array with boost converter: an open loop study, Unpublished B.Tech project report submitted to Department of Electrical Engineering, National institute of technology, Rourkela. 7. Dev, A. and Jeyaprabha, S.B. 2013. Modeling and Simulation of Photovoltaic Module in MATLAB, Proceedings of the International Conference on Applied Mathematics and Theoretical Computer Science: 268-273. 8. Dunford ,W.G., Xiao, W. and Capel, A. 2004. A Novel Modeling Method for Photovoltaic Cells, 35th Annual IEEE Power Electronics Specialists Conference: 1950-1956. 9. Hadjab, M., Berrah, S. and Abid, H. 2012. Neural network for modeling solar panel, International Journal of Energy, Vol. 6, Issue 1: 9-16.
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Voltage and frequency controller for three Phase Four Wire Hybrid System for Loads in Isolation Mukesh Sahi, B.P. Chouhan Government Polytechnic College Banswara, Rajasthan, India-327001 ABSTRACT: Wind driven Self Excited Induction generator (IG) and Permanent magnet synchronous generator (PMSG) along with Solar photovoltaic (SPV) power generating system are combined to feed the variety of loads like linear/non-linear balanced/unbalanced loads in isolated regions. Powers from all sources are combined at common coupling point with battery energy storage system (BESS). Nonlinear and unbalanced loading condition demands reactive power from the system. Whole system with load side controller is simulated in the MATLAB Simulink and the system performance is evaluated during nonlinear and unbalanced loading condition. Source side controller maintains the PMSG output maximum and also achieve a maximum torque for the maximum power tracking with minimum currents. KEYWORDS: Voltage Stability, Wind Turbine, Squirrel-Cage Induction Generator, PMSG, SPV, Common Coupling Point, BESS. synchronous generators (PMSG) are gaining I.INTRODUCTION popularity among the variable-speed wind To cope up with the future power demand and turbines [6]. A PMSG is a rotating electric increased environmental concern, nowadays machine, in which the field excitation is focus is laid on electrical power generation provided by permanent magnets. PMSGs have from renewable energy sources such as wind, a loss-free rotor and the power losses are solar. These sources are the world’s fastest confined to the stator windings and the stator growing energy resources. These are clean and core [7]. A multipole PMSG connected to a effective modern technology that provides a power converter can operate at low speeds and beacon of hope for future energy based on so gear can usually be omitted [8]. A gearless sustainable and pollution free technology. construction represents an efficient and robust These renewable energy sources are located in solution for a WECS. Thus, the efficiency of a remote regions, thereby causing some PMSG based WECS has been assessed to be problems in their development. One solution higher than other variable-speed wind turbine for this is that if local small-scale power systems. systems are developed employing these However, PMSGs have the disadvantage of distributed energy sources, thereby reducing high cost of permanent magnet material in the transmission of the electricity over long present time, which is expected to reduce in distances. The autonomous or distributed the near future. Full scale power converter is generation systems can be used when the grid used in the case of PMSG-based WECSs, connection is not possible. In starting, during which allows the full controllability of the the development of the wind generation for system [9]. The power converter decouples the grid connected systems, the fixed speed wind PMSG from the grid and results in an turbines with squirrel cage induction improved reliability. In the case of a gridgenerators were in use. For such systems the connected variable speed WECS; the total energy conversion efficiency was very low. active power can be fed to the grid. For standNow a day's variable speed wind energy alone systems [6] supplying local loads, if the conversion system (WECS) [1-4] uses the extracted power from the wind is more than maximum power tracker (MPT) [5], which the local loads (and losses), the excess power enables to adjust the rotational speed to is required to be diverted either to a dump load maximize the wind turbine output power. The or to be stored in the battery bank. So the study turbines driving permanent magnet for three-phase four-wire autonomous WECS ISBN-978-81-932091-2-7
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is important because most of the loads in isolated areas, such as islands or remote locations are single-phase distributed loads. Another important renewable energy system is solar photovoltaic (PV) generation system. Sun irradiations are directly converted into electric energy by the use of the PV array. As these irradiations are available in huge amount for a long period of time per day, so it must be harnessed. Keeping it in mind, a system is studied in MATLAB Simpower environment which utilizes the solar energy and the wind energy to supply an isolated area. WECS through the self-excited induction generator is also included in the proposed system. So, three sources PMSG, IG and SPV are supplying the power to the loads and these three sources are joined in parallel at the common DC link. II. SYSTEM For the widely varying wind speeds the energy conversion efficiency of fixed speed wind energy conversion system (WECS) is very low. In many of the modern-day variablespeed WECS, a maximum power tracker (MPT) adjusts the rotational speed to maximize the wind turbine output power. The variable-speed operation of WECS can be achieved in a number of ways. In the case of doubly fed induction generator (DFIG) the power converter needs to handle only the rotor power, which is only a fraction of the total power. Among the variable-speed wind turbines, the turbine driving permanent magnet synchronous generator (PMSG) is gaining popularity. In PMSG, the field excitation is provided by permanent magnets. PMSG have a loss-free rotor, and the power losses are confined to the stator windings and the stator core only [10]. At low speed a gear can usually be omitted if a multi-pole PMSG is used. This gearless construction represents an efficient and robust solution for a WECS. Thus, the efficiency of a PMSG-based WECS is higher than other variable-speed wind turbine systems [11]. In the case of PMSG based WECS, a full- s c a l e power converter is used, which allows the full controllability of the system. In such systems, the power converter decouples the PMSG from the grid, resulting in an improved reliability. For stand-alone systems supplying local loads, if the extracted
power from the wind is more than the local loads (and losses), the excess power is required to be diverted either to a dump load or to be stored in the battery bank. Moreover, when the extracted power is less than the load power, the deficit power needs to be supplied from a storage element like a flywheel, a super capacitor, compressed air, hydrogen storage, a secondary battery [12]. A number of attempts have been made to address the issues of voltage and frequency control (VFC) for stand-alone systems using asynchronous generators [13] [14] [15] [16]. Attempts are made to develop a battery-based controller for a wind-driven autonomous four-wire system using a PMSG and feeding local loads in stand-alone mode without mechanical position sensors. Further this autonomous WECS using PMSG is considered in a hybrid system with the Solar system using photovoltaic array. As solar power is an endless source of energy like wind energy, so developing a hybrid system based on these two freely available energies is a need of the present world. The Three energy sources PMSG, IG and SPV are connected in parallel to a common DC bus line as shown in fig. 1, through their individual converters. The load may be dc-connected to the dc bus line or may include an IGBT based pulse width modulated (PWM) voltage source inverter to convert the DC power into AC at 50 or 60 Hz. Each source has its individual control. The diodes, D1, D2 and D3, allow only unidirectional current flow from the source to the DC bus line, thus keeping each source from acting as a load on each other or on the battery. Therefore, in the event of malfunctioning of any of the energy sources, the respective diode will automatically disconnect that source from the system. The output of the hybrid generating system goes to the DC bus line to feed the isolating DC load or to the inverter, which converts the DC into AC. When the output of the system is not available, the battery powers the DC load or discharges to the inverter to power AC loads. III. PRINCIPLE The operating principle of the controller which controls the load-side converter is based on the control of the reactive power to regulate the ISBN-978-81-932091-2-7
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magnitude of the load voltage and control of active power to regulate the frequency of the voltage. The battery system absorbs the excess active power when the frequency of the load voltage is above the nominal frequency, and it supplies the active power when the frequency is below the nominal frequency. When the magnitude of the voltage falls below the reference value, the load-side converter provides the reactive power, and when the magnitude of the voltage rises above the reference value, the reactive power is absorbed by the load-side converter. For the control of the load-side converter, the reference three-phase phase-to-neutral voltages are compared with the sensed threephase, phase-to-neutral voltages at the load end, and the difference is fed to the voltage controller. The output of the voltage controller gives the reference three-phase load-side converter currents, which are compared with the sensed three-phase load-side converter currents to achieve control signals for the load side converter.
Fig. 1 Block Diagram for Proposed System A.
Machine Side Converter Control
The operating principle of the controller for the machine-side converter is based on the decoupled control of the d-axis and q-axis stator currents of the PMSG with the d-axis aligned to the permanent magnet flux or rotor electrical axis. In the proposed algorithm, the
wind speed is sensed for the MPT. The rotor position (θ ) is estimated using stator flux linkages. The equations and algorithm for the sensor less operation are illustrated through equation 1 to 6. The rotor speed (ω ) is determined from the rotor position (θ ). The reference rotor speed (ω∗ ) for the MPT is generated from the wind speed and the optimum tip speed ratio(TSR) and is compared with (ω ) to calculate the rotor speed error (ω ) at the nth sampling instant as: ω ( ) = ω∗( ) − ω ( ) … … … … … … … … … … … … … … … . (1) At the nth sampling instant, the output of the proportional-integral (PI) speed controller with proportional gain K ω and integral gain K ω gives reference for the q-axis stator current (I ) as: I∗ ( ) = I ( ) + K ω ω ( ) − ω ( ) + K ωω ( ) … … … … . … (2) To obtain maximum torque with minimum stator current, the reference d-axis stator current (I∗ ) is set to zero at the nth sampling instant as: I∗ ( ) = 0 … … … … … … … … … … … … … … … … … . (3) By dq to abc transformation, the reference d-q stator currents (I∗ and I∗ ) are converted to three-phase reference PMSG stator currents (i∗ , i∗ and i∗ ), which are then compared with sensed PMSG stator currents (isa,isb, and isc) to compute the PMSG stator current errors (isaerr,isberr, and iscerr) as: i = i∗ − i … … … … … … … … … … … … … … … . … . . (4) i = i∗ − i … … … … … … … … … … … … … … … … . (5) i = i∗ − i … … … … … … … … … … … … … … … … . . (6) These current errors are amplified with gain (K) and the amplified signals are compared with the fixed frequency (10 kHz) triangular wave to generate gating signals for IGBTs of the machine-side converter. B. LOAD SIDE CONVERTER CONTROL The purpose of the load-side converter is to maintain rated voltage and frequency, irrespective of connected load. The power balance of the load-side converter is ISBN-978-81-932091-2-7
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maintained by diverting excess power carrier wave of unity amplitude to generate generated to the battery in the DC link of backgating signals for IGBTs of the load-side to-back connected PWM converters or by converter. supplying active power from the battery in the IV. SIMULATION AND RESULTS case of a deficit between the generated power and load requirement. Similarly, the required MATLAB simulation of the proposed system, reactive power for the load is supplied by the “Autonomous WECS using PMSG” (Wind load-side converter to maintain a constant Energy Conversion System using Permanent value of the load voltage. The reference Magnet Synchronous Generator), Solar ∗ ∗ ∗ Photovoltaic (SP) and Induction Generator voltages (v , v and v ) for the control of (IG) is done in MATLAB using Simulink, the load voltages at time t are given as: ∗ SimPower System. The simulation is carried ( ) ( ) v = √2V sin 2πft … … … … … … . . 7 ∗ out on MATLAB version R2011a with v = √2V sin(2πft − ode23tb solver. Complete system for WECS 120° ) … … … … … … … … … … … . . … … … (8) using PMSG, SP and IG in isolation is v ∗ = √2V sin(2πft + simulated by combining the simulated models 120° ) … … … … … … … … … … … .. … . . (9) of the WECS, SP, IG, Machine Side Where, ‘f’ is the nominal frequency (50 Hz) Controller, Load Side Controller, and Battery and V is the RMS phase-to-neutral load Energy Storage System (BESS) is shown in voltage (240 V). The load voltages (v , v fig. 2 here two back-to-back connected and v ) are sensed as feedback signals and insulated gate bipolar transistor (IGBT) based error voltages (v ,v and v ) are voltage source converters (VSCs) are calculated from the reference voltages and load connected between the PMSG and the load voltages as: end. The VSCs are controlled through the v ( ) = pulse width modulation (PWM) based v∗ ( ) v ( ) … … … … … … … … … . (10) controllers. A battery bank is connected at ∗ the DC link of these VSCs. An LC filter and a v ( ) = v ( )− step-up-transformer are connected between the v ( ) … … … … … … … … … … … … … 11) load-side converter and the load. ∗ v ( ) = v ( )− v ( ) … … … … … … … … … … … … . (12) The reference three-phase load-side converter currents (i∗ ,i∗ and i∗ ) are generated by feeding the voltage error signals to the PI voltage controllers. The reference three phase load side converter currents are then compared with sensed load side converter currents (i , i and i ) to compute the load side converter current errors as: i = i∗ −i … … … … … … … … … … … … … … . . (13) i = i∗ − i … … … … … … … … … … … … … … . . (14) i = i∗ Figure 2: Simulation diagram for the system − i … … … … … … … … … … … … … … … (15) under consideration. These current errors are amplified with gain (K), and the amplified signals are compared A. SOURCE SIDE CONTROLLER with the fixed frequency (10 kHz) triangular Tm
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The objective of the source side controller is to achieve a maximum torque for the maximum power tracking with minimum currents. The graphs for the source side converter are shown in fig. 3. The output of the Wind turbine driven PMSG is maximized by using maximum power tracking technique and simulated as source side cont roller. Graphs are plotted between the time and the various observed quantities. The input and output of the system are shown through the graph placed in the fig 3. In fig.3 (a) graph shows Cos and Sin values created through PLL by using the three phase per unit voltages generated by PMSG. These Cos and Sin values are used to convert the ‘dq0’ values to three phase ‘abc’ values. Fig. 3(b) & fig. 3(c) represent the input and output values of the PI controller respectively, ‘dq0’ to three phase ‘abc’ conversion is shown in fig. 3(d). Three phase current generated through the PMSG is shown in fig. 3(e). Fig. 3(f) shows the result of subtraction of generated current shown in fig. 3(e) from the values shown in fig. 3(d). These values are given to the PWM generator unit to generate the switching pulses for the source side controller. These switching pulses are shown in fig. 3(g).
load-side converter to maintain a constant value of the load voltage. The graphs for the load side controller are shown in Fig. 7. In fig. 7(a) the graph shows the three phase reference voltage. Fig. 7(b) represents the sensed three phase load voltage. The sensed three phase load voltage is subtracted from the reference three phase voltages and outcome is shown in fig. 7(d), which is directly entered to the PI controller. Fig. 7(e) shows the output of the PI controller. Sensed three phase load current is shown in fig.7 (e) is subtracted from the output of the PI controller shown in fig. 7(d) and the result of subtraction is shown in fig. 7(f). Then these values of fig. 7(f) are given to the PWM generator unit to generate the switching pulses for the load side controller. These switching pulses are shown in fig. 7(g).
Fig. 7 Load Side Controller
Fig. 3 Source Side controller B. LOAD SIDE CONTROLLER The objectives of the load-side converter are to maintain rated voltage and frequency, irrespective of connected load. The required reactive power for the load is supplied by the
C. LINEAR LOAD At starting the system is running with balanced load. At 0.6 sec. an unbalance is created by disconnecting the phase ‘a’ from load, (by opening the connection between phase ‘a’ and its load. This will reduce the active power demanded by the load but cause supply imbalance which affects the source. Further at 0.7 sec. load form the phase ‘b’ is also removed, making the system more unbalanced. At 0.85 sec. both removed phases loads are connected again which ISBN-978-81-932091-2-7
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makes the system a balanced one again. Behavior of the WECS using PMSG, IG and SP is shown by a set of waveforms in fig. 8. Here in the system during the unbalanced to maintain the constant frequency on the load side the extra active power is diverted to the BESS. It is clearly seen from the graphs that the load voltages for all three phases are in balanced condition. The system frequency remains always close to the 50 Hz.
Further at 0.7 sec. load form the phase ‘b’ is also removed from its diode bridge rectifier load, making the system more unbalanced. At 0.85 sec. both removed phases loads are connected which places the system in the previous condition. It is clearly visible in fig. 9 that the voltage and frequency are almost constant even though during the disturbances. V. CONCLUSION Matlab/simulink based simulation of the proposed system shows that the voltage and frequency on load side remains balanced in all electrical loading conditions. The performance of the WECS using PMSG, IG, SPV system feeding balanced/unbalanced resistive, inductive, and non-linear load has been found satisfactory. REFERENCES 1.
Fig. 8 Graph for Linear Balanced/Unbalanced Load D. NON-LINEAR BALANCED/ UNBALANCED System is started with balanced three phase load. At 0.6 sec. an unbalance is created by disconnecting a diode bridge rectifier load from phase ‘a’ (by opening the connection between phase ‘a’ and its load).
2.
3.
4.
5. . Fig. 9 Graph for Non-linear Balanced /Unbalanced Load
T. F. Chan, and L. L. Lai, “Permanent magnet machines for distributed power generation: A review,” IEEE Proceedings of the Power Engineering Society General Meeting, pp. 1–6, June 2007.Rolan, A. Luna, G. Vazquez, “Modeling of variable speed wind turbine with a perman ent magnet synchronous generator”, IEEE International Conference on Electric Machines and Drives, pp. 734-739, July 2009. P. K. Goel, B. Singh, S. S. Murthy, N. Kishore, “Isolated wind-hydro hybride system using cage generators and battery storage,” IEEE Transactions on Industrial Electronics, Vol. 58, No. 4, pp. 11411153, April 2011. M. Abdel-Salam, A. Ahmed, M. AbdelSater, “Harmonic mitigation, maximum power point tracking, and dynamic performance of variable-speed gridconnected wind turbine,” Electric Power Components and System, Vol. 39, No. 2, pp. 176-190, 02 Feb. 2011. X. Yang, X. Gong, and W. Qiao, “Mechanical sensorless maximum power tracking control for direct drive PMSG wind turbine”, IEEE Energy Conversion Congress and Exposition, pp. 4091-4098, sep. 2010. ISBN-978-81-932091-2-7
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6.
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P. K. Goel, B. Singh, S. S. Murthy, and N. Kishore, “Autonomous hybrid system using SCIG for hydro power generation and variable speed PMSG for wind power generation”, IEEE Conference on Power Electronics and Drive Systems, pp. 55-60, nov. 2009. J. Faiz, B. M. Ebrahimi, M. rajabisebdani and A. Khan, “Optimal design of permanent magnet synchronous generator for wind energy conversion considering annual energy input and magnet volume”, IEEE Conference on Sustainable Power Generation and Supply, pp. 1-6, april 2009. S. Miyabukuro, M. Takiguchi,and R. Takhashi, “Modeling and simulation of wind turbine –fed interior permanent magnet synchronous generator”, IEEE Conference on Electrical Machines, pp. 16, sept. 2008. M. Chinchilla, S. Annaltes, and J. C. Burgos,, “Control of permanent-magnet generators applied to variable-speed wind energy systems connected to the grid,” IEEE Transactions on Energy Conversion, Vol. 21, No. 1, pp. 130–135, March 2006. E. Spooner, A.C. Williamson, G. Catto, "Modular design of permanent magnet generators for wind turbines," IEE Proceedings, Electric Power Applications, Vol.143, No. 5, pp. 388-395, Sep. 1996. J. Chen, C.V. Nayar, and L. Xu, "Design and finite-element analysis of an outer rotor permanent-magnet generator for directly coupled wind turbines," IEEE Transactions on Magnetics, Vol. 36, No.5, pp. 3802-3809, Sep 2000. K. Stunz, and J. Nedrud, “Multilevel energy storage for intermittent wind power conversion: Computer system analogies,” IEEE Power Engineering Society General Meeting, pp. 1950–1951, San Francisco, CA, 12–16 June 2005. E. Mulzadi, and T. A. Lipo, “Series compensated PWM inverter with battery supply applied to an isolated induction generator,” IEEE Transactions Industry Applications, Vol. 30, No. 4, pp. 1073– 1082, July/August 1994.
14. R.S Bhatia., D.K Jain., Bhim Singh and S.P. Jain, “Battery energy storage system for power conditioning of renewable energy sources”, in Proc. of IEEE Conference on Power Electronics and Drive Systems, Dec. 2005, pp.501-506. 15. V. Valtchev, A. V. D. Bossche, J. Ghijselen, and J. Melkebeek, “Autonomous renewable energy conversion system,” Renewable Energy,Vol. 19, No. 1/2, pp. 259– 275, January 2000. 16. C. H. Lee and L. Wang, “A novel analysis of parallel operated self-excited induction enerators”, IEEE Transactions on Energy Conversion, vol. 13, No.2, pp. 117123, June 1998.
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Effect of Heat Transfer Fluids on the Techno-Economic Performance of Parabolic Trough based Solar Thermal Power Generation in India Tarun K. Aseria, Chandan Sharmaa, Ashish K. Sharmab, Rahul Rawatc a
Mechanical Engineering Department, Govt. Engineering College, Ajmer, Raj., India. b International Finance Corporation (IFC), World Bank Group, New Delhi, India c Ministry of New and Renewable Energy, New Delhi, India
Abstract The share of renewable energy based electricity generation in total energy mix in India is increasing day by day owing to climatic concerns and resource scarcity associated with fossil fuels. Solar thermal is a prominent option for renewable energy based power generation. The solar thermal technologies like parabolic trough, central tower receiver and linear Fresnel reflector are being used to generate electricity in the different part of the world. In the present study, the effect of heat transfer fluids (Solar salt, Hitec XL, Therminol VP-1, Hitec) on techno-economic performance of a 50MW parabolic trough based solar thermal power plant (without thermal energy storage) has been analyzed. The location of Jaisalmer in the state of Rajasthan, India has been considered for the analysis. Annual energy output has been obtained using System Advisor Model (SAM) simulation tool. Levelized cost of electricity (LCOE) has been computed. The results obtained reveals that Hitec–XL heat transfer fluid provides highest annual electricity output and correspondingly lowest LCOE in comparison to other heat transfer fluids considered in the study. Keywords: Solar thermal power generation; parabolic trough; heat transfer fluid; levelized cost of electricity. (Sharma et al., 2015). Kumar and Reddy (Reddy and Kumar, 2012) have assessed 1. INTRODUCTION feasibility of solar thermal power plant at 58 High rate of GHG emissions and resource potential locations using synthetic oil and scarcity concerns associated with fossil fuel water as working fluids in solar parabolic based electricity generation has renewed the trough field. The study observed that PTC interest of researchers to explore renewable based solar thermal power plants are energy sources for electricity generation (Pitzeconomically viable in India. Feldhof et al. Paal et al., 2003). Solar energy based power (Feldhoff et al., 2012, 2010) have carried out generation is one of the promising noncomparative studies for PTC based solar conventional energy source. Two routes are thermal power plant using water/steam and available to harness solar energy and convert synthetic oil as HTF with and without TES into electrical energy. These are: Solar PV and system. As reported, using direct steam solar thermal (IRENA and ETSAP, 2013; generation (DSG) could lead to reduction in REN21, 2016). The concentrating solar power cost of energy delivered by 11% without TES. (CSP) can play a significant role in shifting Further, recent research is focused on carbon rich energy sector to green energy enhancing thermodynamic performance of sector. Moreover, the option of incorporating solar thermal power plant using different kind relatively inexpensive thermal storage with of heat transfer fluid using nano particles solar thermal power plant is expected to (Cingarapu et al., 2013; Fernández et al., 2014; improve it’s dispatch ability (Sargent & Tiznobaik and Shin, 2013). Lundy, 2003). Several studies have analysed Though numerous studies have envisaged and assessed the effect of various design significant potential of solar thermal power parameters such as collector field, design generation in India (Purohit et al., 2013; direct normal irradiance (DNI), solar multiple Ramachandra et al., 2011; Sharma et al., (SM), thermal energy storage (TES), type of 2014), very few studies have been reported that heat transfer fluid (HFT) on techno-economic deals with study of effect of design parameters performance of solar thermal power plant ISBN-978-81-932091-2-7
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on the techno-economics of solar thermal power generation. In the present study, an attempt has been made to investigate the effect of heat transfer fluids (Solar salt, Hitec XL, Therminol VP-1, Hitec) on techno-economic performance of a 50MW parabolic trough based solar thermal power plant in India. The plant without thermal energy storage has been chosen for the study.
2.
Site selection for the study
The analysis of the techno-economic performance of solar thermal power plants in India is primarily based on available annual direct normal irradiance (DNI) in the region. As reported, the locations with annual DNI more than 1800 kWh/m2 are technically and economically viable for deployment of solar thermal power plants (Purohit and Purohit, 2017). Figure 1 shows the distribution map of the daily average DNI for India. It is observed that most of the northern-western region is having high DNI and hence significant potential for solar thermal power generation exist. . The site selected for the present analysis is falling in the same region. The geographic and environmental characteristics of the potential location i.e. Jaisalmer in the state of Rajasthan is summarized in Table 1. The monthly variation of ambient temperature and DNI for the location of Jaisalmer is presented in Figure 2.
3.
PTC based solar power plant
Majority of operational solar thermal power plants across the globe are parabolic trough based as the technology is relatively more mature than central tower receiver and linear Fresnel reflector. Further most of the operational plants are of 50 MW nominal capacity. Hence, a 50 MW parabolic trough based solar thermal plant has been considered in the study. A schematic flow diagram of the 50MW Rankine cycle based solar thermal power plant is shown in Figure 3. In this cycle, the cold heat transfer fluid (HTF) gets heated in the solar collector field by incident solar radiation. This heated heat transfer fluid exchanges its heat and convert water into superheated steam in the steam generator. This high pressure (100 bar) and high temperature (375°C) steam is expanded in various stages of various turbines i.e. high pressure (H.P.),
intermediate pressure (I.P.) and low pressure (L.P.) turbine. The outlet steam from the L.P. turbine is condensed back into water in the condenser and recycled to steam generator using feed water pumps and heaters. In the present study, the technical data pertaining to one of the operational 50 MW PTC based solar thermal plant (Megha solar power plant located in Anantpur, Andhra Pradesh) has been taken for evaluation of electricity output and same are presented in Table 2.
4.
Heat transfer fluids
The selection of optimum heat transfer fluid (HTF) is important aspect for overall technoeconomic performance and efficiency of CSP plant over its entire useful life. Besides exchanging heat in steam generator, the HTF can also be used as thermal storage media to generate electricity in hours of no or intermittent sunshine. The selection of appropriate HTF depends on several desired physical characteristics including higher thermal stability at higher temperature, high thermal conductivity and boiling point, low viscosity and melting point, low corrosive nature and low cost (Batuecas et al., 2017). High heat capacity for storage is essential characteristic of HTF (González-Roubaud et al., 2017a). Based on material used, the heat transfer fluids can be : (a) water/steam, (b) thermal oils, (c) organic fluids, (d) molten salts, (e) liquid metals and (f) air/other gases (Vignarooban et al., 2015). In the present study, the performance CSP plant with commonly used thermal oil (Therminol VP-1) as HTF has been compared with three different molten salts. Table 3 presents characteristics of heat transfer fluids selected for the analysis.
5.
Economic analysis
As mentioned earlier, the Megha Solar Plant has been chosen as reference plant and capital cost (US $2690/kW) of same has been considered for the analysis (SolarPACES, 2016). The capital cost used in the study is adjusted for the present year (i.e. 2017) (Decelerates and Flatten, 2017). The levelized cost of electricity (LCOE) has been estimated from the following expression (Kandpal and Garg, 2003): ISBN-978-81-932091-2-7
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(Capitalcost capitalrecoveryfactor) annualO & M cost Annualelectricity output
(2) Capital recovery factor (CRF) is given by: d (1 d ) n CRF (1 d ) n 1 (3) where d is discount rate and n is useful life of the plant. In the present study, a discount rate of 10%, useful life of 25 years has been assumed. Annual operation and maintenance (O&M) cost has been assumed as 2% of the capital cost.
Table 1 Details of location selected for the analysis Latitude
oE
Longitude
o
Wasteland
26.91
N
70.95 2
km
16762 2
DNI
kWh/m
1883
Dry bulb Temperature Wind speed
(ºC) m/s
28.65 4.89
Rainfall
mm
181.2
Figure 3: Schematic of solar thermal power plant
Figure 1: Daily average direct normal irradiance map for India Ambient temperature
40
240
35
220
30
180
20 160
15
140
10
Dec
Oct
Nov
Sep
Jul
Aug
Jun
Apr
100 May
0 Mar
120 Jan
5
Figure 2: Monthly variation of ambient temperature and direct normal irradiance
DNI (W/m²)
200
25
Feb
Ambient temperature (ºC)
DNI
Table 2 Design parameters used in simulation for 50MW PTC based solar thermal power plants(SolarPACES, 2016) Parameter Value Collector AlbiasaTrough AT150 Receiver Siemens UVAC 2010 Heat Transfer fluid Therminol VP-1 Irradiation at Design (W/m2) 700 Solar multiple 1.20 Reflected area (m2) 366,240 Land Area (km2) 1.3 Year to year decline in Nil output Table 3 Characteristics of heat transfer fluids (González-Roubaud et al., 2017b; Jung et al., 2015) Heat Thermin Solar Hitec transfer Hitec ol VP-1 salt XL fluid NaNO3 NaNO3 C12H10 NaNO3 (7), (7), Compositio (73.5), (60), KNO3 KNO3 n (wt%) C12H10O KNO3 (45), (53), (26.5) (40) Ca(NO3) NaNO2 (40) 2 (48) Minimum operating 12 238 120 142 temperature o ( C) Maximum 400 593 500 538 operating ISBN-978-81-932091-2-7
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6.
764.3
1871.8
1956.5
1828.6
2.457
1.502
1.432
1.56
0.00059
0.0032 6
0.00637
0.0031 6
Results and discussion
The annual electricity output for the proposed solar thermal plants has been obtained using system advisor model (SAM). SAM is freeware renewable energy technology simulation tool and is developed by the National Renewable Energy Laboratory (NREL), USA (SAM, n.d.). The National Solar Radiation Database (NSRDB) source has been used for weather data (NREL - NSRDB, n.d.). The monthly energy output obtained for a 50MW PTC based solar thermal power plant using different heat transfer fluids is presented in Figure 4. It is observed that the variation in energy output follows the variation in monthly DNI values. Table 4 summarizes annual energy output, capacity utilization factor (CUF) and levelized cost of electricity (LCOE) for plant with different HTFs. As shown in the Table 4, the plant with Hitec – XL HTF generate relatively higher annual electricity output and hence minimum LCOE amongst the other HTF (Figure 5). The primary reason for the same can be attributed to relatively superior thermodynamics properties. Therminol VP-1
Solar Salt
Hitec
Hitec XL
Energy output (GWh)
14.00 12.00 10.00 8.00 6.00 4.00 2.00 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
0.00 Months of the year
Figure 4 Monthly variation in energy output
Table 4 Annual energy output, capacity utilization and cost of energy delivered with different HTFs Annual Heat Electricity CUF LCOE transfer output (%) (₹/kWh) fluid (GWh) Therminol 105.5 24.1 10.8 VP-1 Solar Salt 107.0 24.4 10.6 Hitec 103.3 23.6 11.0 Hitec XL 110.8 25.3 10.3 11.2 11.0 LCOE (₹/kWh)
temperature (oC) Density (kg/m3) Specific heat (kJ/kgK) Kinematic viscosity (at 300 oC) (Pa-s)
10.8 10.6 10.4 10.2 10.0 9.8 Therminol Solar Salt VP-1
Hitec
Hitec XL
Figure 5 Variation in levelized cost of electricity for different HTFs
7.
Concluding remarks
An attempt has been made to analyze the effect of various heat transfer fluids on the technoeconomics of a 50 MW solar thermal power plant in India. The location of Jaisalmer in Rajasthan has been selected for the same. Technical data pertaining to an operational plant in India has been used. Four different heat transfer fluids were used, and it was found that annual electricity output with the use of Hitec XL is maximum (Rs. 110.8 GWh) and LCOE is minimum (Rs. 10.3 per kWh). Further, annual electricity output with the use of Hitec heat transfer fluid is minimum (103.3 GWh) and LCOE is maximum (Rs. 11.0 per kWh). This reveals that among other parameters, the selection of proper heat transfer fluid has considerable impact on annual electricity output and cost of electricity delivery.
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Batuecas, E., Mayo, C., Díaz, R., Pérez, F.J., 2017. Solar Energy Materials and ISBN-978-81-932091-2-7
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https://sam.nrel.gov/download (accessed 3.3.17). 20. Sargent & Lundy, 2003. Assessment of Parabolic Trough and Power Tower Solar Technology Cost and Performance Forecasts:NREL/SR-550-34440, National Renewable Energy Laboratory (NREL). 21. Sharma, C., Sharma, A.K., Mullick, S.C., Kandpal, T.C., 2015. Identifying Optimal Combinations of Design for DNI, Solar Multiple and Storage Hours for Parabolic Trough Power Plants for Niche Locations in India, in: Energy Procedia. pp. 61–66. doi:10.1016/j.egypro.2015.11.478 22. Sharma, C., Sharma, A.K., Mullick, S.C., Kandpal, T.C., 2014. Assessment of solar thermal power generation potential in India. Renew. Sustain. Energy Rev. 41.
23. SolarPACES, 2016. NREL: Concentrating Solar Power Projects [WWW Document]. URL http://www.solarpaces.org/csptechnology/csp-projects-around-theworld (accessed 10.12.16). 24. Tiznobaik, H., Shin, D., 2013. Enhanced specific heat capacity of high-temperature molten salt-based nanofluids. Int. J. Heat Mass Transf. 57, 542–548. doi:10.1016/j.ijheatmasstransfer.2012.10. 062 25. Vignarooban, K., Xu, X., Arvay, a., Hsu, K., Kannan, a. M., 2015. Heat transfer fluids for concentrating solar power systems – A review. Appl. Energy 146, 383–396. doi:10.1016/j.apenergy.2015.01.125
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Determination of optimum heat rejection pressure in transcritical N 2O refrigeration cycle with vortex tube 1
Gaurav Jain, 2Akhilesh Arora, 3S. N. Gupta 1 Department of Mechanical Engg., JSS Academy of Technical Education, Noida, UP 201301, 2 Department of Mechanical Engineering, Delhi Technological University, Delhi 110042, 3 Department of Mechanical Engineering, IIT, BHU, Varanasi, UP 221005, India Corresponding author E-mail: gauravjain@jssaten.ac.in
Abstract In a transcritical vapour compression cycle heat rejection pressure plays an important role and it has an optimum value corresponding to the maximum coefficient of performance (COP) of the cycle. In the present paper, with a thermodynamic simulation model, the optimum heat rejection pressure has been studied for the transcritical cycle with vortex tube (TCVT) having refrigerant N 2O. The effects of various parameters (compressor efficiency, vortex tube nozzle efficiency, gas cooler outlet temperature, evaporator temperature, cold mass fraction and water inlet temperature to desuperheater) on the optimum heat rejection pressure are analyzed. Based on the cycle simulations, correlation of the optimum heat rejection pressure in terms of appropriate parameters have been developed for considered operating conditions. The correlation offers significant help in the design and control of the transcritical N 2O refrigeration cycle with vortex tube. Keywords: Refrigeration cycle, Nitrous oxide, Vortex tube, expansion valve, Optimum heat rejection pressure. List of symbols COP Coefficient of performance â&#x201E;&#x17D; Specific enthalpy (kJ kg-1) đ?&#x2018;&#x192; Pressure (MPa) đ?&#x2018;&#x17E; Cooling effect (kJ kg-1) đ?&#x2018;Ą Temperature (0C) TCEV Transcritical cycle with expansion valve TCVT Transcritical cycle with vortex tube đ?&#x2018;Ľ Dryness fraction Greek letters Âľ Cold mass fraction đ?&#x153;&#x201A; Compressor isentropic efficiency đ?&#x153;&#x201A; Vortex tube nozzle efficiency đ?&#x153;&#x20AC; Effectiveness of desuperheater Subscripts đ?&#x2018;? Cycle with expansion valve đ?&#x2018;? Gas cooler outlet e Evaporator đ?&#x2018;&#x161; Cycle with vortex tube opt Optimum đ?&#x2018;&#x; Improvement (%) đ?&#x2018;¤đ?&#x2018;&#x2018; Water inlet to desuperheater 1-9 State points of refrigerant
1. Introduction The applications of natural refrigerants such as carbon dioxide, nitrous oxide, propane, isobutene, ammonia is gaining their importance due to their zero-ozone depletion potential (ODP) and low global warming potential (GWP). In transcritical refrigeration cycles carbon dioxide (CO2) has already gained large acceptance, whereas its counterpart nitrous oxide (N2O) is still not fully explored. N2O and CO2 have similar properties in terms of critical pressure, temperature and molecular weight (Kruse et al. 2006). The N2O exhibits five times lower toxicity than CO2, however its GWP (240) is higher than CO2 (1) but it falls under the low GWP category (Agrawal et al. 2011). Some studies have been reported on use of N2O in transcritical refrigeration systems (Sarkar and Bhattacharyya, 2010; Agrawal et al., 2011). In the mentioned studies, it is shown that transcritical N2O cycle performs higher cooling COP, lower discharge pressure and temperature ISBN-978-81-932091-2-7
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with higher exergetic efficiency compared to equivalent transcritical CO2 cycle. The transcritical vapour compression cycle has heat rejection process in supercritical region and evaporation process in subcritical region. Therefore, the expansion loss in the throttle valve from the high pressure transcritical region into the two-phase region is not so small. The loss of this useful energy can be overcome by using the vortex tube in place of expansion valve in transcritical refrigeration cycle. The studies on vortex tube expansion transcritical cycles shows that vortex tube instead of expansion valve in transcritical cycle improves the maximum COP and reduces the optimum heat rejection pressure (Li et al., 2000; Christensen, 2001; Sarkar, 2009; Xie et al. 2011; Liu and Jin, 2012; Jain et al. 2017). Heat rejection pressure is an important parameter in transcritical refrigeration cycle, and it has an optimum value corresponding to maximum COP. The optimum heat rejection pressure in transcritical cycle with expansion valve (TCEV) has been investigated by many researchers (Kauf, 1999; chen et al. 2005; Aprea et al. 2009; Cecchinato et al. 2010). Sarkar (2009) also developed expressions for optimum heat rejection pressure for vortex tube expansion transcritical CO2 refrigeration cycles based on maurer and keller models. However, the correlation for optimum heat rejection pressure for transcritical cycle with vortex tube (TCVT) using N2O as refrigerant is scarce in open literature. In the present study, the analyses have been done on the optimum heat rejection pressure based on the maximum COP for the vortex tube expansion transcritical N2O cycle with layout based on maurer model (1999). A correlation for the optimal heat rejection pressure has been developed in terms of system operating parameters. The correlation can provide a guideline to the system design and optimization of a transcritical N2O cycle with vortex tube. 2. Transcritical N2O refrigeration cycle with vortex tube
A transcritical N2O refrigeration system consists of a compressor, a gas cooler, an evaporator, and an expansion device. The expansion device can be either a throttle valve or vortex tube. The schematic diagram of transcritical cycle with vortex tube (TCVT) for Maurer model (1999) is shown in Fig.1 and the corresponding P − h (pressure-enthalpy) diagram is shown in Fig. 2.
Fig. 1 Schematic diagram of transcritical cycle with vortex tube for Maurer Model
Fig. 2 P-h diagram of transcritical cycle with vortex tube for Maurer Model As shown in Fig. 1, the superheated refrigerant N2O enters the compressor at state 1 and compressed adiabatically to state 2. The superheated gas is then cooled to state 3 in a gas cooler. The refrigerant coming out from the gas cooler expands through the vortex tube nozzle (state3a) and separates into three parts i.e. saturated vapour (state 5), superheated vapour (state 6) and saturated liquid (state 4). The saturated liquid collects in a ring inside the vortex tube. The saturated vapour and liquid are ISBN-978-81-932091-2-7
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mixed again (state 8) at the inlet of evaporator. In the evaporator the refrigerant N2O absorbs the heat and converts into saturated vapour (State 9). The superheated vapour (state 6) is sensibly cooled in the desuperheater to state 7 and mixed with the saturated vapour leaving the evaporator (state 9) before entering the compressor (state 1). In the transcritical cycle with expansion valve (TCEV) the refrigerant enters the compressor as saturated vapour (state 9) and exits at state 2b, which is shown by a dotted line in Fig. 2. The expansion in the throttle valve (expansion valve) is isenthalpic (process 3-y is not shown in P-h diagram). 3. Thermodynamic modeling and Simulation The thermodynamic model based on conservation of mass and energy as proposed by Sarkar (2009) is considered for the analysis. Following assumptions are made for analysis: (i) The refrigerant leaving the vortex tube separates into three parts; saturated vapour (state 5), saturated liquid (state 4) and superheated vapour (state 6). (ii) The pressure drops in various components and connecting pipes of the system are neglected. (iii) The mixing and separation processes in the cycle are isobaric. (iv) The process inside the compressor is irreversible adiabatic. (v) The refrigerant at the exit of evaporator is dry saturated vapour. (vi)The hot fluid leaving the vortex tube absorbs all the kinetic energies. The mass of the refrigerant (N2O) coming out from the gas cooler has been taken as one kg for analysis. Suppose dryness fraction of refrigerant at state 3a is â&#x20AC;&#x2DC;đ?&#x2018;Ľâ&#x20AC;&#x2122; and the cold mass fraction is â&#x20AC;&#x2DC;Âľâ&#x20AC;&#x2122;. Then fraction [đ?&#x2018;Ľ â&#x2C6;&#x2014; Âľ] is separated as saturated vapour, liquid [1 â&#x2C6;&#x2019; đ?&#x2018;Ľ] is separated as saturated liquid and rest [đ?&#x2018;Ľ â&#x2C6;&#x2014; (1 â&#x2C6;&#x2019; Âľ)] absorbs all the kinetic energies and separated as superheated vapour.
The actual enthalpy at exit of vortex tube nozzle can be calculated using equation (1). â&#x201E;&#x17D; = â&#x201E;&#x17D; â&#x2C6;&#x2019; đ?&#x153;&#x201A; (â&#x201E;&#x17D; â&#x2C6;&#x2019; â&#x201E;&#x17D; ) (1) Where đ?&#x153;&#x201A; is the nozzle efficiency of vortex tube, Energy conservation equation for vortex tube is given by equation (2). â&#x201E;&#x17D; = (1 â&#x2C6;&#x2019; đ?&#x2018;Ľ)â&#x201E;&#x17D; + Âľđ?&#x2018;Ľâ&#x201E;&#x17D; + (1 â&#x2C6;&#x2019; đ?&#x153;&#x2021;)đ?&#x2018;Ľâ&#x201E;&#x17D; (2) Energy conservation at the inlet of Evaporator (1 â&#x2C6;&#x2019; đ?&#x2018;Ľ + đ?&#x153;&#x2021;đ?&#x2018;Ľ)â&#x201E;&#x17D; = (1 â&#x2C6;&#x2019; đ?&#x2018;Ľ)â&#x201E;&#x17D; + đ?&#x153;&#x2021;đ?&#x2018;Ľâ&#x201E;&#x17D; (3) Using the effectiveness of desuperheater đ?&#x2018;Ą can be calculated by equation (4) đ?&#x2018;Ą = đ?&#x2018;Ą â&#x2C6;&#x2019; đ?&#x153;&#x20AC; (đ?&#x2018;Ą â&#x2C6;&#x2019; đ?&#x2018;Ą ) (4) Where đ?&#x153;&#x20AC; is the effectiveness of superheater and đ?&#x2018;Ą is the temperature of water at inlet to desuperheater, Energy conservation at the inlet of compressor â&#x201E;&#x17D; = (1 â&#x2C6;&#x2019; đ?&#x2018;Ľ + đ?&#x153;&#x2021;đ?&#x2018;Ľ)â&#x201E;&#x17D; + (1 â&#x2C6;&#x2019; đ?&#x153;&#x2021;)đ?&#x2018;Ľâ&#x201E;&#x17D; (5) Cooling capacity of the system is given by equation (6) đ?&#x2018;&#x17E; = (1 â&#x2C6;&#x2019; đ?&#x2018;Ľ + đ?&#x153;&#x2021;đ?&#x2018;Ľ)(â&#x201E;&#x17D; â&#x2C6;&#x2019; â&#x201E;&#x17D; ) (6) Compressor work đ?&#x2018;¤ = â&#x201E;&#x17D; â&#x2C6;&#x2019; â&#x201E;&#x17D; = (â&#x201E;&#x17D; â&#x2C6;&#x2019; â&#x201E;&#x17D; )/đ?&#x153;&#x201A; (7) Where đ?&#x153;&#x201A; is the isentropic efficiency of the compressor The COP of the transcritical cycle with vortex tube can be evaluated using equation (8) ( )( )Ă&#x2014; đ??śđ?&#x2018;&#x201A;đ?&#x2018;&#x192; = = (8) The COP of the basic cycle i.e. transcritical cycle with expansion valve (TCEV) is computed using equation (9) đ??śđ?&#x2018;&#x201A;đ?&#x2018;&#x192; = (â&#x201E;&#x17D; â&#x2C6;&#x2019; â&#x201E;&#x17D; )/(â&#x201E;&#x17D; â&#x2C6;&#x2019; â&#x201E;&#x17D; ) (9) The percentage COP improvement with vortex tube over expansion valve is given by đ??śđ?&#x2018;&#x201A;đ?&#x2018;&#x192; = (đ??śđ?&#x2018;&#x201A;đ?&#x2018;&#x192; â&#x2C6;&#x2019; đ??śđ?&#x2018;&#x201A;đ?&#x2018;&#x192; ) â&#x2C6;&#x2014; 100/đ??śđ?&#x2018;&#x201A;đ?&#x2018;&#x192; (10)
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From equation (8), the COP of the transcritical cycle with vortex tube has maximum value when the partial derivative of the COP with respect to the heat rejection pressure (đ?&#x2018;&#x192;) is equal to zero
Water temperature at inlet to desuperheater (đ?&#x2018;Ą ) = 50 C to 350 C Cold Mass Fraction (Âľ) = 0.3 to 0.8
i.e.
4.1 Effect of evaporator temperature on optimum heat rejection pressure and maximum cooling COP
(11)
The heat rejection pressure resulting in a maximum đ??śđ?&#x2018;&#x201A;đ?&#x2018;&#x192; is called as the optimum heat rejection Pressure đ?&#x2018;&#x192; , which can be determined with đ?&#x2018;&#x192; = đ?&#x2018;&#x192; (đ?&#x2018;Ą , đ?&#x2018;Ą , đ?&#x153;&#x201A; , đ?&#x153;&#x201A; , đ?&#x153;&#x20AC; , đ?&#x153;&#x2021;, đ?&#x2018;Ą ) (12) From equation (12), it is clear that optimum heat rejection pressure in a transcritical N2O cycle with vortex tube mainly depends on gas cooler outlet temperature, evaporation temperature, compressor and vortex tube nozzle efficiency, desuperheater effectiveness as well as on cold mass fraction and water temperature inlet to the desuperheater. Based on the above analysis, a simulation model for transcritical N2O cycle with vortex tube using EES software (Klein and Alvarado 2012) is developed and optimum value of the heat rejection pressure is calculated. 4. Results and Discussion The following input parameters have been considered for the analysis of transcritical cycle with vortex tube based on maurer mode. Refrigerant N2O has been used in the TCVT as well as in TCEV for analysis. Vortex tube nozzle efficiency (đ?&#x153;&#x201A; ) = 0.75 Desuperheater effectiveness (đ?&#x153;&#x20AC; ) = 0.85 Gas cooler outlet temperature (đ?&#x2018;Ą ) = 350 C to 600 C Evaporator temperature (đ?&#x2018;Ą ) = -550 C to 50 C Compressor isentropic efficiency (đ?&#x153;&#x201A; ) = 0.80
Fig. 3 shows the variations of optimum heat rejection pressure (đ?&#x2018;&#x192; ) of TCVT and TCEV with evaporation temperature (đ?&#x2018;Ą ) for đ?&#x2018;Ą =450 C, Âľ = 0.5 and đ?&#x2018;Ą = 250 C. The optimum pressure for both the cycles increases with decrease of evaporator temperature for refrigerant N2O. It is clear from the figure that the đ?&#x2018;&#x192; is higher for TCEV compared to TCVT for all considered values of evaporator temperature. The value of optimum gas cooler pressures for TCVT and TCEV varies from 10.93 to 9.78 MPa and from 11.85 to 9.86 MPa respectively, for the considered evaporator temperatures. It shows that evaporator temperature has significant effect on the optimum heat rejection pressure of both the cycles. 12 Optimum heat rejection pressure(MPa)
=0
TCE V
11.5 11 10.5 10 9.5 -55
-45
-35
-25
-15
-5
5
Evaporator temperature (â ° C)
Fig. 3. Variation of optimum discharge pressure for TCVT and TCEV at different evaporator temperatures Fig. 4 shows the variation of COP values of the two cycles with the evaporator temperature (đ?&#x2018;Ą ) for the đ?&#x2018;Ą =450 C, Âľ = 0.5, đ?&#x2018;Ą = 250 C and at the optimum heat rejection pressure (đ?&#x2018;&#x192; ).The maximum cooling COP for both the cycles increases on increasing the values of evaporator ISBN-978-81-932091-2-7
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2.5 2.3 2.1 1.9 1.7 1.5 1.3 1.1 0.9 0.7 0.5
Maximum COP
co pb
temperature, the TCVT tends to show the advantage in lowering the system pressure. The value of gas cooler pressures for TCVT and TCEV varies from 7.42 to 14.97 MPa and from 7.49 to 15.81 MPa respectively, for considered gas cooler exit temperatures. It shows that gas cooler exit temperature has great influence on the optimum heat rejection pressure of both the cycles.
Optimum heat rejection pressure(MPa)
temperatures. It is also observed that maximum cooling COP of TCVT is higher compared to TCEV for all the values of evaporator temperatures. The maximum cooling COP for the TCVT and TCEV varies from 0.70 to 2.37 and from 0.61 to 2.27 respectively for considered evaporator temperatures, whereas the maximum cooling COP for TCVT is 14.41 % and 4.36 % higher than TCEV corresponding to evaporator temperatures of -550 C and 50 C respectively. It can be concluded that the application of vortex tube instead of expansion valve is more beneficial at lower values of evaporator temperature to reduce the optimum heat rejection pressure and increase the maximum cooling COP.
16.5 15.5 14.5 13.5 12.5 11.5 10.5 9.5 8.5 7.5 6.5
TC EV
35
40
45
50
55
60
Gas cooler outlet temperature ( â °C)
-55
-45
-35
-25
-15
-5
5
Evaporator temperature (â ° C)
Fig. 4. Variation of maximum cooling COP for TCVT and TCEV at different evaporator temperatures 4.2 Effect of gas cooler exit temperature on optimum heat rejection pressure and maximum cooling COP Fig. 5 shows the variations of đ?&#x2018;&#x192; for TCVT and TCEV with gas cooler exit temperature (đ?&#x2018;Ą ) for đ?&#x2018;Ą = -200 C, Âľ = 0.5 and đ?&#x2018;Ą = 250 C. The optimum pressure increases with the gas cooler exit temperature for both TCVT and TCEV. The value of đ?&#x2018;&#x192; for TCVT is lower compared to TCEV at all the considered values of gas cooler exit temperatures. It is observed that at low value of gas cooler outlet temperature, both the cycles have very close optimum heat rejection pressure, whereas on increasing the gas cooler
Fig. 5. Variation of optimum heat rejection pressure for TCVT and TCEV at different gas cooler outlet temperatures Fig. 6 shows the variation of COP values of the two cycles with the gas cooler exit temperature (đ?&#x2018;Ą ) for the đ?&#x2018;Ą = -200 C, Âľ = 0.5, đ?&#x2018;Ą = 250 C and at the optimum heat rejection pressure (P ). It is observed that the cooling COP for both the cycles decreases rapidly with the increase of gas cooler outlet temperatures. The maximum cooling COP of TCVT is higher compared to TCEV for all the gas cooler outlet temperatures. The maximum cooling COP for the TCVT and TCEV varies from 1.84 to 0.94 and from 1.78 to 0.82 respectively for the considered gas cooler outlet temperatures, whereas the maximum cooling COP for TCVT is 2.97 % and 14.96 % higher than TCEV corresponding to gas cooler temperatures of 350 C and 600 C respectively. It is concluded from the figures 3, 4, 5 & 6 that lower values of gas cooler exit temperatures and higher evaporator temperatures are the necessary ISBN-978-81-932091-2-7
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conditions not only for the maximum COP but also for lower values of P . 12.5
Maximum COP
1.8
co pb
1.6 1.4 1.2 1 0.8 0.6 35
40
45
50
55
60
Optimum heat rejection Pressure (MPa)
2 11.5 10.5 9.5
đ?&#x2018;Ą = -200 C, đ?&#x2018;Ą = 450 C, Îź = 0.5, đ?&#x2018;Ą = 250C, đ?&#x153;&#x20AC; =0.85, đ?&#x153;&#x201A;đ?&#x2018;Ł =0.75
8.5 7.5
Gas cooler outlet temperature ( â °C) 6.5
Fig. 6. Variation of maximum cooling COP for TCVT and TCEV at different gas cooler outlet temperatures 4.3 Effect of đ?&#x203A;&#x2C6;đ??Ż , đ?&#x203A;&#x2C6;đ??&#x153; , đ?&#x203A;&#x2020;đ???đ??&#x17E; , đ?&#x203A;?, đ?? đ??°đ??? on optimum heat rejection pressure Figs. 7 and 8 shows the variation of optimum heat rejection pressure (P ) with the vortex tube nozzle efficiency ( đ?&#x153;&#x201A; ) and compressor isentropic efficiency (đ?&#x153;&#x201A; ) respectively for TCVT at đ?&#x2018;Ą = -200 C, đ?&#x2018;Ą = 450 C.
0.6
0.65
0.7
0.75
0.8
0.85
0.9
0.95
Compressor isentropic efficiency
Fig. 8. Optimum heat rejection pressure versus the compressor isentropic efficiency Figs. 9 and 10 shows the variation of optimum heat rejection pressure (P ) with the desuperheater effectiveness (đ?&#x153;&#x20AC; ) and cold mass fraction (đ?&#x153;&#x2021; ) respectively for TCVT at đ?&#x2018;Ą = -200 C, đ?&#x2018;Ą = 450 C.
Optimum heat rejection pressure (MPa)
Optimum heat rejection Pressure (MPa)
12.5 12.5
11.5
11.5
10.5
10.5 9.5
đ?&#x2018;Ą = -200 C, đ?&#x2018;Ą = 450 C, Îź = 0.5, đ?&#x2018;Ą = 250C, đ?&#x153;&#x201A; =0.80, đ?&#x153;&#x201A; =0.75
9.5
đ?&#x2018;Ą = -200 C, đ?&#x2018;Ą = 450 C, Îź = 0.5, đ?&#x2018;Ą = 250C, đ?&#x153;&#x201A; =0.80, đ?&#x153;&#x20AC; =0.85 =0.85
8.5 7.5
8.5 7.5
6.5 0.6
0.65
0.7
0.75
0.8
0.85
0.9
0.95
Vortex tube nozzle efficiency
6.5 0.6
0.65
0.7
0.75
0.8
0.85
0.9
0.95
Desuperheater effectiveness
Fig. 7. Optimum heat rejection pressure versus the vortex tube nozzle efficiency
Fig. 9. Optimum heat rejection pressure versus the Desuperheater effectiveness ISBN-978-81-932091-2-7
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From the Figs. 7, 8,9,10 and 11, it is concluded that the effect of various parameters (Ρ , Ρ , ξ , Ο, t ) are negligible on the optimum heat rejection pressure of TCVT.
Optimum heat rejection pressure (MPa)
12.5 11.5
4.4 Correlation for optimal heat rejection pressure
10.5 9.5
đ?&#x2018;Ą = -200 C, đ?&#x2018;Ą = 450 C, đ?&#x153;&#x201A; =0.80, đ?&#x2018;Ą = 250C, đ?&#x153;&#x20AC; =0.85, đ?&#x153;&#x201A;đ?&#x2018;Ł =0.75
8.5 7.5 6.5 0.3
0.4
0.5
0.6
0.7
0.8
Cold mass fraction
Fig. 10. Optimum heat rejection pressure versus the cold mass fraction Fig. 11 shows the variation of optimum heat rejection pressure (P ) with the water inlet temperature to desuperheater (đ?&#x2018;Ą ) for TCVT at đ?&#x2018;Ą = -200 C, đ?&#x2018;Ą = 450 C. Optimum heat rejection pressure (MPa)
12.5 11.5 10.5 9.5
đ?&#x2018;Ą = -200 C, đ?&#x2018;Ą = 450 C, Îź = 0.5, đ?&#x153;&#x201A; =0.80, đ?&#x153;&#x20AC; =0.85, đ?&#x153;&#x201A;đ?&#x2018;Ł =0.75
8.5
In engineering systems correlations are widely employed to provide a quick guideline and reasonable accurate results. As described from Equation (12), the optimal heat rejection pressure for TCVT can be correlated with gas cooler outlet temperature, evaporation temperature, compressor and vortex tube nozzle efficiency, desuperheater effectiveness, cold mass fraction and water temperature inlet to the desuperheater, whereas the results show that optimum heat rejection pressure only depends on evaporator and gas cooler exit temperatures. The effect of other parameters (Ρ , Ρ , Îľ , Îź, t ) are negligible on optimum gas cooler pressure. Therefore, the optimum heat rejection pressure can be considered as a function of the evaporator temperature and the gas cooler outlet temperature. The simulation results of the optimum heat rejection pressure are shown at different evaporator and gas cooler exit temperatures in Table 1. It is clear from the table that the effect of gas cooler exit temperature is significant on the đ?&#x2018;&#x192; compared to evaporator temperature. Table 1. Variation of P (MPa) for TCVT with gas cooler temperature (t ) and evaporator temperature (t ) tc
tâ&#x201A;&#x2018;=5â ° C
Optimum heat rejection pressures (MPa) tâ&#x201A;&#x2018;= -5â ° tâ&#x201A;&#x2018;=tâ&#x201A;&#x2018;=tâ&#x201A;&#x2018;=tâ&#x201A;&#x2018;=15â ° C 25â ° C 35â ° C 45â ° C C
tâ&#x201A;&#x2018;= 55â ° C
35
7.209
7.293
7.38
7.754
40
8.488
8.624
8.762
8.9
9.04
9.18
9.32
45
9.787
9.979
10.17
10.362
10.554
10.745
10.934
50
11.139
11.385
11.632
11.879
12.126
12.371
12.612
55
12.57
12.864
13.165
13.469
13.772
14.072
14.366
60
14.1
14.436
14.787
15.145
15.504
15.859
16.206
7.5 6.5 5
10
15
20
25
30
35
Inlet water temperature to desuperheater (â ° C)
Fig. 11. Optimum heat rejection pressure versus the inlet water temperature to desuperheater
7.471
7.563
7.658
From the simulation results, a correlation has been obtained to predict the optimal heat ISBN-978-81-932091-2-7
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rejection pressure (in MPa) for transcritical N2O refrigeration cycle with vortex tube (R2=99.54%), as given in equation (13) đ?&#x2018;&#x192; = â&#x2C6;&#x2019;1.0951 â&#x2C6;&#x2019; 0.022đ?&#x2018;Ą + 0.1847đ?&#x2018;Ą + 0.00128đ?&#x2018;Ą (13) Where, R2 signifies the perfectness of data fitting. This correlation is valid for evaporator temperature (đ?&#x2018;Ą ) of -550 C to 50 C and gas cooler exit temperature (đ?&#x2018;Ą ) of 350 C to 600 C. Conclusions In the present study, thermodynamic model of TCVT and TCEV are analyzed for the effect of heat rejection pressure on COP. Based on the simulation results of the cycles, following conclusions can be drawn. (1) For a transcritical N2O refrigeration cycle with expansion valve or vortex tube, there exists an optimal heat rejection pressure that gives a maximum COP. (2) The TCVT has high COP and low optimum pressure compared to TCEV at all the considered evaporator and gas cooler temperatures. (3) The analysis of TCVT reveals that the values of the optimum heat rejection pressure mainly depend on the evaporator and gas cooler exit temperatures. The effects of other parameters (compressor efficiency, vortex tube nozzle efficiency, gas cooler outlet temperature, evaporator temperature, cold mass fraction and water inlet temperature to desuperheater) are negligible. (4) A correlation has been obtained for the optimum heat rejection pressure in terms of evaporator and gas cooler temperatures. This correlation offer useful guidelines for system development and performance optimization of a transcritical N2O refrigeration cycle with vortex tube. References 1. Agrawal, N., Sarkar, J., Bhattacharyya, S. (2011).â&#x20AC;&#x153;Thermodynamic analysis and
optimization of a novel two stage transcritical N2O cycleâ&#x20AC;? International Journal of Refrigeration 34:991â&#x20AC;&#x201C;999. 2. Aprea, C., Maiorino, A.,(2009) â&#x20AC;&#x153;Heat rejection pressure optimization for a carbon dioxide split system: an experimental studyâ&#x20AC;? Appl. Energy 86 : 2373-2380. 3. Cecchinato, L., Corradi, M., Minetto, S.(2010) â&#x20AC;&#x153;A critical approach to the determination of optimal heat rejection pressure in transcritical systemsâ&#x20AC;?Appl. Therm. Eng.30 : 1812-1823. 4. Chen, Y., Gu, J.,(2005) â&#x20AC;&#x153;The optimum high pressure for CO2 transcritical refrigeration systems with internal heat exchangersâ&#x20AC;? Int. J. Refrig. 28 :1238-1249. 5. Christensen, K.G., Heiredal, M., Kauffeld, M., Schneider, P. (2001).â&#x20AC;&#x153;Energy savings in refrigeration by means of a new expansion device.â&#x20AC;? Report of Energy researchprogramme, Journal no. 1223/99â&#x20AC;&#x201C; 0006. 6. Jain, G., Arora, A.,Gupta, S., (2017). â&#x20AC;&#x153;Performance analysis of a transcritical N2O refrigeration cycle with vortex tubeâ&#x20AC;?International journal of ambient energyâ&#x20AC;?. http://dx.doi.org/ 10.1080/ 01430750.2017.1399449 7. Kauf, F.,(1999) â&#x20AC;&#x153; Determination of the optimum high pressure for transcritical CO2 refrigeration cyclesâ&#x20AC;? Int. J. Therm. Sci. 38: 325-330 8. Klein, S.A., Alvarado, F. (2012). Engineering Equation Solver, Version 9.224, F-chart Software, Middleton,WI. 9. Kruse, H., RĂźssmann, H. (2006).â&#x20AC;&#x153;The natural fluid nitrous oxideâ&#x20AC;&#x201D;an Option as substitute for low temperature synthetic refrigerants.â&#x20AC;?International Journal of Refrigeration 29: 799-806. 10. Li, D., Baek, J.S., Groll, E.A. and Lawless, P.B. (2000) â&#x20AC;&#x2DC;Thermodynamic analysis of vortex 11. tube and work output expansion devices for the transcritical carbon dioxide cycleâ&#x20AC;&#x2122;, Fourth
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12. IIR-Gustav Lorentzen Conference on Natural Working Fluids at Purdue, Purdue University, 13. USA, pp.433–440. 14. Liu, Y., Jin, G. (2012).“Vortex tube expansion two-stage transcritical CO2 refrigeration cycle”. Advanced Materials Research 516-517: 1219-1223. 15. Maurer, T. (1999). Patent DE 197 48 083 A1, Entspannungseinrichtung. 16. Sarkar, J. (2009).“Cycle parameter optimization of vortex tube expansion transcritical CO2 system”. International Journal of Thermal Sciences 48: 1823-1828. 17. Sarkar, J., Bhattacharyya, S. (2010).“Thermodynamic analyses and
optimization of a transcritical N2O refrigeration cycle.”International Journal of Refrigeration 33:33–40. 18. Xie, Y.B., Cui, K.K. , Wang, Z.C. , Liu, J.L. (2011).“CO2 trans-critical two stage compression refrigeration cycle with vortex tube.” Applied Mechanics and Materials 5254: 255-260. 19. Zhang, X. , Wang, F., Fan, X., Wei, X., Wang, F. (2013) “Determination of the optimum heat rejection pressure in transcritical cycles working with R744/R290 mixture” Appl. Therm. Eng. 54 : 176-184.
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Impact of Renewable Energy Generation on Bidding Strategy a
Md Irfan Ahmed a, Deepti Bhatia b and Aditya Sharma c Career Point University, Electrical Engineering Department, Kota, Rajasthan, India Corresponding Author: irfannitp.ahmed@gmail.com , deeptib442@gmail.com
Abstract Renewable energy resources (RER) are the fastest growing energy resources in the world. RER exist over wide geographical areas, in contrast to other energy sources, which are concentrated in a limited number of countries. National renewable energy markets (REM) are projected to continue to grow strongly in the coming decade and beyond. Due to need of such a source we need a well- managed alternative which is abundant and easy to access. Most of the renewable energy resources had been installed in the distribution systems as distributed generation. The change in the generation mix from conventional electricity sources to renewables has important implications for bidding behaviour and may have an impact on prices. The principle objective of this paper is to determine the role played by expected renewable energy production, together with other relevant factors, in explaining the dayahead market price. It is suggested that the solar and wind power forecasts are a new key determinant for supply market participants when bidding in the day-ahead market. We also provide a conservative quantification of the effect of such trading strategies on marginal prices at an hourly level for a specific year in the sample. Keywords: - Renewable energy resources (RER), Renewable energy markets (REM), Competitive electricity market (CEM), Bidding strategy (BS) 1. INTRODUCTION fight climate change has been the creation of Nowadays Electricity Price forecasting has carbon emission markets [1]. been a vital and essential issue in every nation. 1.1 Indian Installed Capacity in 2017 Because of deregulation, the price for electricity has come to be determined by competitive bidding by producers and consumers in the wholesale day-ahead market, where an auction system is generally followed. The electricity supply function is discontinuous and increases with the level of demand [4]. The resulting price from the auction, the so-called marginal price, corresponds to the highest price offered by the supply side from those accepted to satisfy demand. The offered prices to sell electricity will, in turn, depend on production costs and these significantly differ among the generation technologies. Therefore, the generation mix of a specific market area, among other factors, will likely condition the resulting marginal prices and the success of a given market design. Due to greater climate awareness, the inclusion of renewable production in the electricity system is a goal in Table 1: All India Installed Capacity (In MW) most countries. Apart from the promotion of 2017 renewable generation, another measure taken to ISBN-978-81-932091-2-7
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In the Indian case, the development and integration of renewable electricity production in the electricity market has been a target for the regulator over the last decade. Tables 1 show the annual figures for installed power capacity and electrical energy in India per generation technology in 2017. 2. BIDDING STRATEGY In most of the country’s Electricity market is planned as a day-ahead market where, the electricity energy transactions are cleared for each hour of the next day. In day-ahead market, demand is estimated for each trading interval, example one-hour period, twenty-four hours ahead and offers and bids are received from the market participants.
The changes from regulation to competition in Electrical industries around the world have led to the improvement of markets for Electricity. Day-ahead electricity markets are emerging as an important medium through which power is allocated in many de-regulated environments. A day-ahead electricity market is a short-term hedge market that operates a day in advance of
the actual physical delivery of power. In these environments, the generation decisions for the next day are in most cases the result of a double (two-sided) auction where producing (selling) and consuming (buying) agents submit a set of price-quantity curves (bids). The bids must be submitted by a deadline on the day before actual delivery of power. A clearing price based on the submitted bids is determined by the ISO (Independent System Operator) or market making agent and all subsequent trades are settled at this price [2]. 2.1 Factors Affecting the Price of Electricity 1. Climate conditions 2. Constraints 3. Communication traffic 4. Fuel costs 5. Unit cost productions 6. Bidding strategies 7. Demand and supply Management 8. Power shortage 9. Outages of generation power plants 10. Market Policy 3. REM IN BIDDING STRATEGY One advantage of the Indian auction format is that it is more technology-neutral and thus provides another way to promote robust competition in REM. The electricity market is structured to guarantee matching between the offers from generators and the bids from consumers at each node of the power network according to an economic merit order [1]. To perform this task, the exchanges starts one day ahead on the basis of daily energy demand forecasting and then successive market sections refine the offers with the aim of both satisfying the balancing conditions and of preserving the power quality and the security of energy supply. 4. RENEWABLE ENERGY IMPACT ON BS The auction provides a unique opportunity to participate in the new competitive wholesale ISBN-978-81-932091-2-7
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electricity market and retain the traditional opportunity of selling to the utility under a long-term purchase power contract [3]. Increase in consumer choice and their participation in short and long-term demand management, as well as growing responsibility to secure their own energy.
Models for Power Producers, Springer-Verlag Berlin Heidelberg, 41-59, Doi 10.1007/978-3642-23193-3_2 [4] Cristina Ballester and Dolores Furió, 2017. Impact of Wind Electricity Forecasts on Bidding Strategies, International Journal of Sustainable Energy, 1-17, doi:10.3390/ su9081318
6. CONCLUSION The use of renewable energy sources is creating a new energy market where it is of the utmost importance to be in condition to anticipate trends and needs from users and producers to reduce inefficiencies in energy management and optimize production. In the CEM every participant wants to enhance its profit by using information announced by market operator. The participation of RES in the Indian electricity market not only led to a decrease in equilibrium prices, but also caused a change in combined cycle bidding strategy in the spot market. Such a decrease in prices forced combined cycle producers to change their bids, so that they could afford their production costs when they are matched in the pool. We observe that (i) combined cycle plants bid now at lower prices and that (ii) their participation in adjustment markets has increased. The question now is if the market price reductions entailed by RES are enough to pay for the increasing costs of the adjustment markets. REFERENCES [1] I.L.R. Gomes, H.M.I. Pousinho, R. Melíco, V.M.F. Mendes, 2016. Bidding and Optimization Strategies for Wind-PV Systems in Electricity Markets Assisted by CPS. Energy Procedia, 106, 111-121. doi: 10.1016/j.egypro.2016.12.109. [2] M. Begović, A. Pregelj, A. Rohatgi and D. Novosel, 2001. Impact of Renewable Distributed Generation on Power Systems, Proceedings of the 34th Hawaii International Conference on System Sciences, 1-10. [3] Roy H. Kwon and Daniel Frances, 2012. Optimization-Based Bidding in Day-Ahead Electricity Auction Markets: A Review of ISBN-978-81-932091-2-7
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Review of Different Energy Resources Sandeep Kumara and Emarti Kumarib a
Department of Computer Engineering, St. Wilfred’s Institute of Engineering & Technology, Ajmer, Rajasthan b Department of Mechanical Engineering, M.B.M. Engineering College, Jodhpur, Rajasthan
Abstract The demand of Electricity is increasing day by day on the earth, because the global population is increasing continuously. At present, approximately the global population is nearly eight billion people, but one third of the population do not have electricity. Thus, we are looking for alternative energy resources for example renewable energy, fossil fuel energy, nuclear energy, hydro energy, etc. The objective of this research paper is to study the various aspects for instance power consumption rate and power production rate of energy. Keywords: Renewable Energy; Fossil Fuel Energy; Nuclear Energy. 1. Introduction In now a day the electricity consumption is growing faster than energy production. It is expected that during the period 2000 to 2040 in all fields and regions the annual demand will increase by 2.3 % per year was reviewed by researchers [1 – 3]. Hence, further research and review is necessary to estimate the exact demand and production of energy through various energy resources. There are many forms of energy resources available for example fossil energy, nuclear energy, renewable energy sources. Mostly countries are using fossil energy as their primary energy sources and nuclear energy as secondary to meet their requirement from day by day, but these sources are not satisfactory and appropriate source of energy and not better for environment. Because fossil and nuclear energy resources are limited. Therefore, for securing the future of coming generations we have to switch on environmental friendly energy resources. This leads to the usage of renewable sources in many parts of the world. Renewable energy is easily available in abundance in most parts of the world and is the most readily available free source of energy. Renewable energy is to be the most appropriate green energy and is environmental friendly. The amount of solar energy incident on the earth's surface is approximately 1.53 × 1018
kW/year, which is about 10,000 times the current annual energy consumption of the entire earth. 2. Energy Energy is the extensive property that can be transferred from one form to another form for example heat to chemical reactions and chemical reactions to thermal energy similarly thermal energy to mechanical energy and mechanical energy to electrical energy or vice versa. An energy resource can produce heat, move objects and produce electricity. The Common forms of energy are kinetic energy of a moving object and the potential energy stored by an object's position in a force field gravitational, electric or magnetic, the elastic energy stored by stretching solid objects, the chemical energy released when a fuel burns, the radiant energy carried by light, and the thermal energy due to an object's temperature. The people are using several energy’s for: residential, commercial, transportation, and industries. Human energy consumption has grown regularly throughout human and earth history. Living organisms require available energy to stay alive, such as the energy from food. Early humans had modest energy requirements, mostly food and fuel for fires to cook and keep warm. In today society humans ISBN-978-81-932091-2-7
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consume as much as 200 times as much energy per person as early humans. Most of the energy we use today come from fossil fuels. But fossils fuels have a disadvantage in that they are non-renewable on a human time scale, and also causes other potentially harmful effects on the environment. Human civilization requires energy to function, which it gets from energy resources such as fossil fuels, nuclear fuel and renewable energy. The processes of Earth climate and ecosystem are driven by the radiant energy Earth receives from the sun and the geothermal energy contained within the earth. Between 2015 and 2040, world energy consumption increases by 30% in the IEO (international energy organization) 2017. 2.1 Energy Resources
Figure 1. Various available energy resources’ 2.1.1 Fossil fuel production and consumption Fossil fuels continuously have a dominant role in global energy systems. Fossil energy was a fundamental driver of the industrial revolution, and the technological, social, economic and development progress which has followed. Energy has played a strongly positive role in global development.
However, fossil fuels also have negative impacts, being the dominant source of local air pollution and emitter of CO2, CO, NO2 and other greenhouse gases. The world must therefore balance the role of energy in social and economic development with the need to decarbonise, reduce our reliance on fossil fuels, and transition towards lower-carbon energy sources. Fossil energy sources available in the form of Coal, Natural Gas, Oil, Sustainability, are expressed in Figure 1. Fossil energy resources are presented by yellow colour because it is reducing continuously due to extraction of resources day by day. The 20th century saw a large diversification of fossil energy consumption, with coal declining from 96% of total production in 1900 to less than 30% in 2000 and 20% in 2040. Today, crude oil is the largest energy source, accounting around 40% of fossil energy, followed by coal and natural gas at 33% and 28% respectively. 2.1.2 Nuclear energy Nuclear energy is energy in the core of an atom. Everything around you are made up of tiny objects called atoms. Atoms are tiny particles that make up every object in the universe. Most of the mass of each atom is concentrated in the centre and the rest of the mass is in the cloud of electrons surrounding the nucleus. Protons and neutrons are subatomic particles that comprise the nucleus. Under certain circumstances, the nucleus of a very large atom can split in two. In this process, a certain amount of the large atom’s mass is converted to pure energy following Einstein’s famous formula E = MV2, where M is the small amount of mass and C is the speed of light. Nuclear energy can be used to make electricity. It can be released from atom in two ways as shown in Figure 1. Nuclear fusion and nuclear fission, in nuclear fission atoms are split apart to form smaller atoms releasing energy and in nuclear ISBN-978-81-932091-2-7
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2.1.3 Renewable energy resources Renewable energy is energy that is collected from natural resources which are naturally replenished on a human timescale such as sun, wind, rain, tide, waves, hydropower, biomass and geothermal heat. Typically, renewable energy resources have much lower greenhouse gas and other emissions associated with use. The renewable energy resources are cleaner and offer a sustainable supply of energy and nature friendly. As of 2015 worldwide, more than half of all new electricity capacity installed was renewable. Renewable energy resources have much lower greenhouse gas and other emissions associated with use. Thus, world is switching to renewable energy resources frequently comparatively primary, secondary energy resources. Various (3.1 Solar energy. 3.2 Wind power. 3.3 Wave and tidal power. 3.4 Geothermal. 3.5 Biomass. 3.6 Hydropower) available renewable energy resources are shown in Figure 1. With green
colour because these resources are healthy for human’s, animals and surrounding’s. 2.2 Energy Consumption Continent wise energy consumption is given in the Table 1. from 2006 to 2016. In the Table also elaborated growth rate per annum of energy consumption. It is observed from Table that due to increasing the use of renewable energy fossil energy consumption is decreases in Europe & Eurasia and South & Cent. America by 0.4 % and 1 % respectively. Here, also observed the average growth rate per annum reduction in year 2016 as compared to year 2006 to 2015 as shown in Figure 2. Table 1. Different continent energy consumption Year
Africa
North America
Europe & Eurasia
Asia Pacific
3924.3
South & Cent. Middle America East Energy consumption (million tonne oil equivalent) 2006
334.8
567.8
592.2
2824.1
3023.5
2007
347.9
593.9
625.6
2866.5
3017.7
4175
2008
369.5
613.2
667.6
2819.2
3022.2
4292.1
2009
373.4
606
690.3
2689.7
2839.8
4402.2
2010
388.9
641.7
734.2
2777.8
2952.6
4674.7
2011
388
665.4
750.3
2778.6
2937.9
4935.1
2012
402.9
680.9
780.8
2724.3
2936.3
5095.5
2013
415.4
696.7
812.4
2795.9
2900.6
5245
2014
427.9
704.1
840
2821.2
2838.3
5357.2
2015
433.5
710.4
874.6
2792.4
2846.6
5447.4
2016
440.1
705.3
895.1
2788.9
2867.1
5579.7
Growth rate per annum 2016 20062015
1.20%
-1.00%
2.10%
-0.40%
0.40%
2.10%
2.80%
2.80%
4.50%
-0.20%
-0.40%
3.90%
7000 Consumption (Mil. tonne oil equ.)
fusion energy is released when atoms are combined or fused together to form a larger atom. Nuclear energy is represented by red colour, because the emission rays due to nuclear fusion and nuclear fission is very dangerous for humans, animals and surrounding. Thus nuclear energy is not environmental friendly. But, nuclear energy is great resources of energy as given here: The first commercial nuclear power stations started in the 1950s. There are over 450 commercial nuclear power reactors operable in 32 countries, with over 396,000 MW of total capacity and 70 more reactors are under construction. Nuclear plant provides over 16% of the world's electricity as continuous reliable power to meet base-load demand without CO2 emissions. 55 countries operate a total of about 250 research reactors, and a further 180 nuclear reactors.
6000
Africa S. & Cent. America Middle East North America Europe & Eurasia Asia Pacific
5000 4000 3000 2000 1000 0 2006
2008
2010
2012
2014
2016
Year ISBN-978-81-932091-2-7
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Consumption (Mil. tonne oil equ.)
7000 6000
Africa S. & Cent. America Middle East North America Europe & Eurasia Asia Pacific
5000 4000 3000 2000 1000 0 2006
2008
2010
2012
2014
2016
Year
Figure 2. Energy consumption per annum 3. Summary In this communication authors have reviewed the consumption of various energy resources for example fossil energy, nuclear energy and renewable energies in last twelve years by world wise. Here, also noticed the value of renewable energy for instance: solar energy, biomass, wave and tidal energy, wind energy and hydro energy, etc. from environment point of view as well as future perspective wise. References 1. Sumit, W. & Walke, P.V. (2017). Review on wind- solar hybrid system, International Journal of Research in Science & Engineering, 3 (2), 71-76. 2. Anwarul, H.M. & Dubey, R.R. (2014). Solar Energy – An Eternal Renewable Power Resource, International Journal of Advanced Research in Electrical, Electronics and Instrumentation Engineering, 3 (2), 7344 – 7351. 3. Christenseen, E. (2015). Electricity Generation, 173. 4. Schiffer, H.W. (2016). World Energy Resources. World Energy Concil. 5. Dudley, B. (2017). BP Statistical Review of World Energy.
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A Review of CFD Methodology used for Solar Devices Himanshu Pandya Dept. of Mechanical Engg, Techno India NJR Institute of Technology, Udaipur, Rajasthan, India Corresponding Author Email: erhimanshupandya@gmail.com Abstract Tremendous need of renewable energy development is very much felt in every part of the globe and sun energy is a prime source of renewable energy, many different techniques and devices are created to harness this vast amount of clean energy source as an alternative to the fossil fuels. Experiments on the physical models and prototypes has been done to create a higher efficiency device but they are time-consuming and costly processes and with the development in the field of computer, scientist and inventors are equipped with the powerful technique of numerical or computational fluid dynamics (CFD) simulation. With the help of numerical or CFD simulation various parameters and effects are check prior to building a physical system with a good accuracy. This article discusses the computational approach used by various researchers in developing various solar systems such as solar water heater, solar air heater and solar still. And also, about the advantages and limitations of the computational approach. In this review it is found out that CFD results are validates with the experimental results and various parametric study can be done more efficiently.CFD is a powerful tool of the analysis of the physical problem. Keywords: Solar energy, solar water heater, solar air heater, solar still, CFD.
1. Introduction The sun is a major source of renewable free energy (i.e. solar energy) for our planet Earth. With the modernization new technologies are being employed to generate energy from harvested solar energy. These approaches have already been proven and are widely practiced throughout the globe as renewable alternatives to conventional nonrenewable energy sources [1]. Also use of solar energy for domestic and industrial heating purposes has also increased. With the increase in demand in solar energy due to the following reasons: 1. Solar energy is free and available for most of the year for the major part of the globe. 2. It is pollution free and also helps in carbon reduction in the world [2]. 3. It is Available in abundance such that it can full fill all the world demand if its harvesting and supplying technologies are readily available [3].
Itâ&#x20AC;&#x2122;s now a great challenge for engineers, researchers, scientist and inventors to create such devices which can easily and efficiently harness, store, and utilize this immense source of pollution free energy. This required great amount to research has to be done, which is also happing in more advance ways then it was before. The analysis of solar devices was carried out in the literature using three approaches as stated below 1. Experimental 2. Theoretical (mathematical) 3. Computational approach. In this paper, main objective is to highlight the latest work done in Computational approach for solar devices with brief introduction and comparison with Experimental approach. 2. Methods or approaches for solar devices analysis A solar device involves the physics of fluid and heat flow. For analyzing the solar devices its thermal and hydraulic performance has to be ISBN-978-81-932091-2-7
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predicted. To evaluate its thermal and hydraulic performance, solar devices can be analyzed using experimental, theoretical or analytical and numerical or computational approach (i.e. CFD). 2.1 Experimental approach In experimental approach, a prototype (actual dimensions or scaled model) of a solar device is manufactured and on it experiments are performed. Thermal and hydraulic parameters like temperature, pressure, flow etc are measured to evaluate the performance of the device. Various factors like cost of manufacturing the device, time required for research, experimental facility and measurement devices, apart from these human error, measurement error and atmospheric condition play a critical role in the accuracy of the research data from the experimental method [4]. 2.2 Analytical approach In theoretical or analytical approach, mathematical equations which are generally partial differential equations represent the governing equation of the physics are used. These are solved using various mathematical analytical approach but the solving a higher order complex equation is a difficult task. To solve these complex equations researcher, use various assumption such that equation becomes easy to solve and the results obtained from it matches with the experimental results [5]. 2.3 Computational approach Computational approach is the latest approaches for analysis, it uses numerical solutions to the mathematical governing equations with the help of powerful computational software like ANSYS FLUENT, ANSYS CFX, CFD ++, Open FOAM, GASP CFL 3D, TYPHON etc. In CFD governing equations which are in the form of integrals or the partial derivatives are converted into discretized algebraic which gives the solutions at discrete points. The main
three elements of every CFD codes are (i) a pre- processor, (ii) a solver and (iii) a postprocessor 2.3.1. Pre-processing In Pre-processing a 3D model of the object of interest is created, and then this domain is divided into number of smaller domain which is known as grid generation or meshing. Smaller element thus formed from meshing is also known as cell and solution to the governing equation are defined at nodes inside each cell. As the number of cell increases accuracy and cost of computational also increases. Fluid properties and boundary conditions are also stated in this step. 2.3.2 Solver Governing equations are converted into discrete system of algebraic equation using suitable discretization procedure such as finite difference method (FDM), finite element method (FEM) or finite volume method (FVM). In CFD codes FVM is mostly preferred. Now these algebraic equations are solved by an iterative method. 2.3.3 Post-processing Post processing is use to examine the results, it includes the visualization tools like contour plots, vector plots, line and shaded plots, 2D and 3D surface plots etc. and also numerical reporting tools to examine various properties like pressure, temperature, heat transfer coefficient etc. of the system. 2.3.4 Validation Table 1 Difference between experimental and computational approach [6] Experimental
Computational
Experiments are expensive to setup These are time consuming Modification in setup is difficult Large number of measuring instruments required
Except initial software cost, it is less costly Less time consuming as compare to experimental Modification can be done easily Various tools are available for calculating
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)” December 2223, 2017 at GEC Banswara, www.apgres.in
Not limited to complexity of problem
the the
Limited number of experimental data and at limited time period But gives real solution to the problem
Availability of mathematical model sets limit to the complex problem No such limitation of time and space Solution accuracy depends upon approximation taken during simulations
CFD solution of physical problem must be validated with the experimental data to ensure sufficient accurate description of the reality. In many conditions no experimental data is available; simulation process is carried out with scale model for which experimental results are available and then it is extended for full scale model. Table 1 shows the difference between experimental and computational 3. CFD methodology for solar devices Bouhal et al. [7] have simulate two different configuration of solar water heater’s storage tank, one with the charge inlet and outlet in horizontal direction (Configuration A) and other having charge inlet and outlet in vertical direction (Configuration B). In both the configurations effect of flat plate inside the tank as an obstacle to flow has been studied. The flat plate is located horizontally in different position in Configuration A and tilted in various angle in Configuration B has been simulated. The following conclusions were drawn from their analysis: (1) CFD framework has been done to evaluate thermal stratification in vertical solar storage. (2) CFD codes are validated with the experimental work done before and a good agreement between them has been found out. (3) The optimum case for configuration A is when two horizontal plates located at the Middle and Top in the tank. (4) The optimum case for configuration B is when plate is tilted 30°.
D.G. Gunjo et al. [8] have carried out experiment and CFD analysis on the novel type solar collector.CFD analysis of a single bent riser tube attached to an absorber plate has been done. Their results reveal that: (1) CFD results are validated with the experimental setup with low deviation in the results. (2) For the investigated solar collector with 60°C outlet water temperature maximum thermal efficiency of 71% was obtained. (3) The simulation model of the collector gives the outlet water temperature, energy efficiency, absorber plate temperature, and overall heat loss coefficient with maximum error of 9%. Both experiment and CFD analysis have been carried out by Facao [9] to analyze the flow distribution in solar collectors which is done first time on the varying diameter solar collector which are generally of constant diameter. The main outcomes were: (1) There is good agreement between CFD and experimental results. (2) The header manifold dimension of the outlet must be greater than that of the inlet for better results. ANSYS CFX was used by H.N. Panchal et al. [10] to simulate the solar still model and validate with the experimental setup. Their results show that: (1) the average deviations from CFD and experimental values for production rate and water temperature are 6.0% and 10.25% respectively. (2) ANSYS CFX is very powerful tool for design, difficulty removal in solar still construction and parameter analysis. A computational analysis using ANSYS FLUENT has been carried out by Khare et al. [11] on simple solar still The main observations from their study were: (1) Simulation results were found to be in good agreement with the experimental data within the scope of their study. (2) Thermal efficiency of the Solar Still is higher from 16:00 to 17:00 hrs. (3) Rubber is found to be one of the best basin materials to improve absorption, storage, ISBN-978-81-932091-2-7
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and evaporation effects. (4) The Solar Still for low water depth has more productivity. Panchal et al. [12 ] performed a CFD simulation and experimental analysis of hemispherical solar still. The conclusions drawn from their analysis were: (1) Distillate water errors of 12 % while comparing with actual experimental results. (2) Also, good agreement with experimental data and average error of water temperature is 8 %. Jin et al. [13] Conducted 3D numerical investigation of solar air heater having multi V-shaped ribs on the absorber plate to study the effect of heat transfer and fluid flow characteristics. The major findings of theirs tudies are listed here – (1) Multi V-shaped ribs promote the fluid mixing between the colder upper channel fluid and the warmer nearbottom-wall fluid by generating the stream wise helical vortex flows. (2) Heat transfer was greatly improved when compared to a smooth wall channel. (3) The maximum values of both the thermo hydraulic performance parameter and average Nusselt number was for Angle of attack of 45°, and an angle of attack of 60° gave the highest value of the friction factor. Yadav et al. [14] simulated a 3D computational domain of roughened solar air heater with nonuniform mesh using V-shaped perforated blocks as artificial roughness on the absorber plate. Their study revealed following conclusions: (1) for perforated V-shaped blockages average enchantment in the Nusselt number was found to be 33% higher than solid blockages. (2) Friction factor blockages were decreased by 32% of the value as observed in solid blockages. Singh et al. [15] investigates a CFD using 3D computational domain of solar air heater to study effect of non-uniform and uniform cross section transverse rib on the friction factor and Nusselt number of roughened solar air heater. The major findings of the study were: (1) For Reynolds number above 7000 the Nusselt number for non-uniform cross-section saw-
tooth rib was more than uniform cross-section ribs. (2) For the range of Reynolds number investigated the Nusselt number for trapezoidal rib was found to be highest followed by square rib and circular rib. (3) CFD results also found in good agreement with the experimental data. 4.Conclusion The conclusions which can be derived from this article are presented here: (1)CFD is a powerful tool for the analysis of the physical problems (2)With the advance in technology and research more number of analysis with CFD are happing all around the world (3)With number of advantages over experimental approach many researchers are performing CFD analysis (4)With growing need of free and clean energy CFD analysis in the field of solar energy is a vast field and lot many work has to be done. (5)Still there is limited number of research available on CFD analysis on solar devices (6) For obtaining results with greater accuracy in CFD; mathematical model, boundary conditions, and assumption made during simulation play a great role (7)But for the final validation of the CFD results experimental data are required. References 1.Solar energy: Potential and future prospects Ehsanul Kabira, Pawan Kumarb, Sandeep Kumarc, Adedeji A. Adelodund, Ki-Hyun Kime, Renewable and Sustainable EnergyReviews 82 (2018) 894–900 2. International Energy Agency. 2D S-hiRen Scenario, Energy Technology Perspectives; 2012. 3. Blaschke T, Biberacher M, Gadocha S, Schardinger I. Energy landscapes: meetingenergy demands and human aspirations. Biomass- Bioenergy 2013;55:3– 16. ISBN-978-81-932091-2-7
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4. Gawande V B, Dhoble A S ,Zodpe D B. Effect of roughness geometries on heat transfer enhancement in solar thermal systems—a review .Renew Sustain Energy Rev2014;32:347–78. 5. Shamardan M M,Norouzi M,Kayhani M H,Delouei A A. An exact analytical solution for convective heat transfer in rectangular ducts .Zhejiang Univ-SciA 2012; 13(10):768– 81 6. A review of CFD methodology used in literature for predicting thermo-hydraulic performance of a roughened solar air heater Vipin B.Gawande , A.S.Dhoble , D.B.Zodpe , Sunil Chamoli Renewable and Sustainable Energy Reviews 54 (2016) 550–605. 7. Numerical modeling and optimization of thermal stratification in solar hot water storage tanks for domestic applications: CFD study T. Bouhala, S. Fertahib, Y. Agrouaza,, T. El Rhafiki, T. Kousksou, A. Jamil ,Solar Energy 157 (2017) 441–455. 8. Exergy and energy analysis of a novel type solar collector under steady state condition: Experimental and CFD analysis Dawit Gudeta Gunjo, Pinakeswar Mahanta, Puthuveettil Sreedharan Robi* Renewable Energy 114 (2017) 655-669. 9. J. Facao, Optimization of flow distribution in flat plate solar thermal collectors with riser and header arrangements, Sol. Energy 120 (2015) 104-112. 10. Hitesh N Panchal, P. K. (2011). Modelling and verification of single slope solar still using ANSYS CFX. International Journal of Energy and Environment, 2(6), 985-998. 11. Modeling and Performance Enhancement of Single Slope Solar Still using CFD Vaibhav Rai Kharea, Abhay Pratap Singhb*, Hemant Kumarc, Rahul Khatrib Energy Procedia 109 (2017) 447 – 455. 12. Experimental and ANSYS CFD simulation analysis of hemispherical solar still, Hitesh N Panchal, P.K. Shah. International Journal of
Renewable Energy, Vol. 8, No. 1, January – June 2013 13.Dongxu Jin, Manman Zhang, Ping Wang, Shasha Xu. Numerical investigation of heat transfer and fluid flow in a solar air heater duct with multi V-shaped ribs on the absorber plate. Energy 2015;89:178–90. 14.Yadav A S, Samant T S, Varshney L. A CFD based analysis of solar air heater having V-shaped perforated blocks on absorber plate. Int Res J Eng Technol 2015;2(2):822–9. 15.Singh S, Singh B, Hans V S, Gill R S.CFD (computational fluid dynamics) investigation on Nusselt number and friction factor of solar air heater duct roughened with non-uniform cross-section transverse rib. Energy 2015; 84:509–17.
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Impact of RES in Distribution Systems Shubham Verma, Devendra Goyal and Pallavi Soni Career Point University, Electrical Engineering Department, Kota, Rajasthan, India Corresponding Author: vermashubham669@gmail.com, devagoyal87@gmail.com Abstract Renewable energy sources (RES) is defined as energy that comes from resources which are naturally replenished on a human time scale such as Wind, sunlight, rain, tides, wave and etc. The high penetration of renewable generations in the distribution system (DS) has introduced more uncertainties and technical challenges in the operation of the grid-like voltage variation, degraded protection, altered transient stability, two-way power flow, and increased fault level. The reverse power flow due to high penetration of renewable generation may result to voltage rise which distribution network operators may not be able to control effectively. This paper impacts the renewable generations such as solar photovoltaic (PV) and wind energy on distribution system with voltage control strategies. The work shows that the application of smart grid technologies such as demand side integration and energy storage mitigate voltage variation problems with minimum network reinforcement. Keywords: - Renewable Energy Sources (RES), Distribution system (DS), photovoltaic (PV), Renewable Generation (RG) 1. INTRODUCTION DS are undergoing a radical transformation, due to several factors which contribute to the evolution of distribution networks into the new concept of smart grid but also greatly influence the grid planning and operation. More specifically, the new distribution grid will be characterized by (i) A massive penetration of dispersed generation units, (ii) The adoption of energy storage technologies for providing services to the grid, (iii) The active participation of end users to grid operation, and (iv) The use of information/communication technologies which enables the information exchange between all the grid resources. [1]. In recent years, the number of renewable generation units connected to distribution networks has continued to grow, and projections are that this process will continue in the future. The reason for this trend is to be found in the increased interest in energy saving and reduction of environmental impact. However, these renewable generation units pose many challenges to grid operators due not only to the
variability of their energy sources but also to their integration into the distribution network. 2. BENEFITS OF DISTRIBUTED ENERGY STORAGE SYSTEM Storage of off-peak PV/wind energy Power smoothing for large solar arrays Peak-load deduction (peak shaving) at substation Distribution and transmission feeder reliability improvement Customer feeder load management Ancillary services (frequent regulation, black start capability). 2.1 Energy Scenario in India
Figure 1: India Energy Scenario 5th largest power generation portfolio. ISBN-978-81-932091-2-7
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5th largest wind energy producer. 20,000 MW of solar power by 2022. 3. ADVANTAGES OF RES One major advantage with the use of renewable energy is that as it is renewable it is therefore sustainable and so will never run out. Renewable energy facilities generally require less maintenance than traditional generators. Even more importantly, renewable energy produces no waste products such as carbon dioxide or other chemical pollutants, so has minimum impact on the environment. Renewable energy projects can also bring economic benefits to many regional areas, as most projects are located away from large urban centers. 4. IMPACT OF RENEWABLE ENERGY IN DS Renewable generation (RG) that comes with distribution system may exhibit a new set of technical problems which often includes problem of voltage rise instead of fall at certain end points with RG integration into the network and sometime the reversal of power flow. Other effect is that, wind turbine is designed to shut down as a safety precaution in very high winds, which means a wind turbine supplying power into the grid might be liable to stop without warning, leading to a sudden drop in production which the network might struggle to compensate for. If the proportion of distributed energy is low, there will not be any problem but when it is getting to 20%, a level proposed by EU countries, then, a risk of global outage is very high. iency, reliability and power quality are very important factors to be considered in the integration of RG with Distributed system others are cost of energy conversion, appropriate load management, security and safety.
Figure 2: Impact of RG on Feeder Voltage Profile 6. CONCLUSION The objective of this paper is to study the effect of RES penetration on voltage stability at the time of connecting and disconnecting wind, solar or both with RES system. It shows the impact of Renewable generation on DS with voltage control strategies and presents the aspect of smart grid technologies in voltage control as the most appropriate voltage control at varying wind speed and PV irradiance. The combination of electrical energy storage and demand side measures one operating from the supply side (Energy Storage), the other from the demand side (DSI), will potentially allow generation plant, both traditional and renewable, to operate in a more cost-effective manner. Coordination of voltage control devices and RG for voltage profile improvement can further be investigated. REFERENCES [1] J.O. Petinrin, and Mohamed Shaaban, 2016. Impact of renewable generation on voltage control in distribution systems. Renewable and Sustainable Energy Reviews, 770-783. http://dx.doi.org/10.1016/j.rser.2016.06.073. [2] M. Begović, A. Pregelj, A. Rohatgi and D. Novosel, 2001. Impact of Renewable Distributed Generation on Power Systems, Proceedings of the 34th Hawaii International Conference on System Sciences, 1-10. [3] Tareq Aziz, Sudarshan Dahal, and N. Mithulananthan and Daniel Frances, 2010. Impact of ISBN-978-81-932091-2-7
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widespread penetrations of renewable generation on distribution system stability, Electrical and Computer Engineering (ICECE), doi: 10.1109/ICELCE.2010.5700697 [4] Dariush Shirmohammadi, 2010. Impacts of high penetration of distributed and renewable resources on transmission and distribution systems, IEEE, Doi: 10.1109/ISGT.2010.5434736
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Microbial pretreated Water hyacinth as an Energy Source Diksha Srivastava Yashwant Raj Verma and Dr. Nafisa Ali Department of Renewable Energy Engineering, College of Technology and Engineering, Maharana Pratap University of Agriculture and Technology, Udaipur -313001, Rajasthan, India. Abstract: The present research work was undertaken to study the potential of water hyacinth in generation of biogas; after a microbial pre-treatment. Water hyacinth, an aquatic weed is often associated with uncontrolled growth and eutrophication. Culture of Phanerochaete chrysosporium, a lingocellulytic fungus was used for microbial pre-treatment. Performance evaluation, in terms of biogas production was checked in 2m3 Modified Deenbandhu biogas plant, which is fitted with a stirrer on its side to remove scum formation in digester. The biogas production from the water hyacinth was only 1.92% more than that of cattle dung but the methane content of the biogas from the water hyacinth was 10.71% higher than that of cattle dung. The average NPK content of the digested slurry of the water hyacinth was 38.55%, 10.52% and 137.14% more than that of digested slurry of cattle dung respectively. This will help to sort out the problems of cooking fuel, lightening, aquatic weed disposal, waste management and sanitation etc. Keywords: Water hyacinth, Modified Deenbandhu biogas plant, phanerochaete chrysosporium, Biomethanation 1. Introduction Water hyacinth (Eichhornia Crassipes) has been identified by the IUCN as one of the 100 most aggressive invasive species (Tellez et al., 2008) and recognized as one of the top 10 worst weeds in the world (Patel 2012). It is characterized by rapid growth rates, extensive dispersal capabilities, large and rapid reproductive output and broad environmental tolerance (Zhang et al., 2010). Among all the control methods such as; physical process, chemical process or biological process, physical process is the best as it provides both rid of water hyacinth which is a major problem for hydrosphere and also provides proper waste disposal of the taken out weed from lakes. Biogas technology in comparison to all other renewable sources of energy is well developed and easy to adopt for any person, as its technological infrastructure is easily available at large scale in Indian market for generating biogas. Biogas is a product of biomethanation process when fermentable organic material such as cattle dung, kitchen waste, poultry droppings, night soil wastes, agricultural wastes etc. are
subjected to anaerobic digestion in the presence of methanogenic bacteria. This process is better as the digested slurry from biogas plants is available for its utilization as organic manure in agriculture and horticulture as a substitute of chemical fertilizers, and in pisciculture as a nutritional feed for fish. 2.
Materials and Methods
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Figure 1: Collection and preparation of water hyacinth for pre-treatment The study was conducted at the Department of Renewable Energy Engineering, College of Technology and Engineering, Udaipur (Rajasthan). Water Hyacinth was collected from the pond of the nearby village named Kanpur, Udaipur (Rajasthan), and was chopped using crusher machine under green house shed, as shown in Figure1. For the microbial treatment of Water Hyacinth, a wood-rot fungus that is capable of degrading lignin via its lignolytic enzymes; Phanerochaete chrysosporium (NCIM 1197) was used. This organism is termed as “white rot fungus” because of its ability to degrade lignin. The cellulosic portion of wood is attacked to a lesser extent, resulting in the characteristic white color of the degraded wood. Degradation of material involves important extracellular enzymes such as lignin peroxidase, manganese dependent peroxidase, glyoxal oxidase and pyranose oxidase (located in the interplasmic space of the fungal cell wall) (Urek and Pazarlioglu, 2007). The vials received from NCIM were kept as parental cultures from which sub-cultures were prepared in malt extract agar medium using slants of test tubes and secondary sub-culture in petri plates as shown in Figure 2.
Figure 2: Sub-cultures of Fungus Further these subcultures were used for preparing mother spawns. For this, one kg of wheat grains was soaked in 1 liter water for overnight. Next day the grains were boiled for 15-20 minutes, after boiling the grains, it was soaked in the same water for 10-15 minutes and then excess water was drained off using a wire mesh sieve. The grains were surface dried on white paper sheet and 12 gm gypsum (CaSO4 2H2O) and 3 gm calcium carbonate (CaCO3) were mixed with these boiled grains, where the gypsum was added to prevent the grains from sticking to each other and calcium carbonate was used to bring the pH to 6.5. The grains were then filled in 500 ml conical flask up to three fourth of the capacity, plugged with non-absorbent cotton and sterilized in autoclave at 120°C + 2°C and 15 lb psi for 1 to 1½ hours. Flasks were ISBN-978-81-932091-2-7
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cooled at room temperature and then were inoculated with colonized mycelium of Phanerochaete chrysosporium by putting the two bits of agar (from petri plates) just opposite to each other in the inner side in the middle of flasks and then incubated at 25 ± 1°C for 2 weeks. The flasks were shaken every day to obtain homogenous growth of fungi. After 2 weeks of inoculation the flasks were ready as spawn culture (Pant et al., 2006). A comparative view of grain filled flasks, before and after sub culturing is shown in Figure 3.
In field level the methodology adopted for treatment of water hyacinth is as under-100 kg of crushed Water Hyacinth was soaked (overnight) in 70-80 lt. of water containing 0.05 percent bavastine and 0.25 percent formaldehyde. This is done to sterilize the organic waste (Deshmukh and Deshmukh, 2013). For fungal treatment, mother spawn of Phanerochaete chrysosporium (prepared previously) was spread on substrate layer by layer in 3 canisters. These canisters were marked and kept at ambient temperature for growth of fungus for 3 days, as shown in Figure 4 (Ali, 2014). Further respectively first, second and third canister was used for feeding biogas plant so as to obtain sufficient growth of microbes for three days and simultaneously filled with fresh material and layer of microbes. This process was repeated till the end of the experiment.
Figure 4: Preparation of mixture of pretreated water hyacinth and cattle dung
Figure 3: Before and after spawn growth
Figure 5: Deenbandhu Biogas Plant with Mixing Unit ISBN-978-81-932091-2-7
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3. Results and Discussion To check the feasibility of water hyacinth as a substrate and adduct for biomethanation, biochemical analysis of water hyacinth and cattle dung was done. All the analysis was done using standard methods as shown in Table No.1. Table 1: Physico chemical analysis of water hyacinth and cattle dung Constitue pH TS VS N P K nts % % % % % Water 6.0 9.6 82. 2.1 0.5 1.6 Hyacinth 8 1 65 6 8 3 Cattle 6.8 10. 81. 1.3 0.5 0.5 dung 2 72 54 8 2 5 The biochemical analysis of the feed material before and after digestion, with respect to pH, total solid content and volatile solid content were done by standard methods and are shown in table 2. Table 2: Characteristics of feed material before and after digestion Days of Observation 10 15 20 25
pH BD AD 6.08 6.83 6.06 6.83 6.05 6.85 6.05 6.92
TS BD 9.60 9.54 9.58 9.62
VS AD 9.10 8.70 8.50 8.10
BD 82.90 82.50 82.60 81.85
AD 82.78 81.25 80.40 78.40
30 35 40 45 50 55 60 65 70 Average
6.07 6.09 6.08 6.09 6.10 6.09 6.10 6.10 6.09 6.08
6.92 6.95 6.96 6.92 6.91 6.87 6.90 6.89 6.87 6.89
9.61 9.59 9.62 9.64 9.64 9.63 9.64 9.62 9.60 9.61
8.00 7.80 7.50 7.46 7.10 7.30 7.40 7.12 7.18 7.78
82.68 82.73 83.18 82.56 82.60 82.87 82.50 82.89 82.63 82.65
77.10 75.80 74.52 74.00 73.72 73.56 72.83 72.75 72.80 76.14
WH: Water Hyacinth, BD: Before Digestion, AD: After Digestion pH value of the water hyacinth before digestion was nearly constant during the whole process. The average value of total solid content of water hyacinth was found to be 7.78% and of cattle dung was found to be 8.10%. Degradation in VS content of water hyacinth was found to be 12.11%, while that in case of cattle dung was found to be 11.10% which indicated the lower biogas production from cattle as compare to water hyacinth. The maximum and minimum temperature of the environment near biogas plant during digestion was found to be 45.70°C and 12.50°C respectively. Production of biogas depends on the degradation of volatile solid matter and here degradation is higher in water hyacinth as compare to cattle dung which clearly indicates the reason of higher biogas production from water hyacinth as compare to cattle dung. Figure 6 shows the biogas produced from water hyacinth and cattle dung graphically, calculated using biogas flow meter during the digestion process.
Biogas (m3)
Initially plant was fed with 100% cattle dung as seeding material to enhance the rate of reaction and then was replaced by pretreated water hyacinth (Ali, 2010) with reduction ratio of 20% (i.e. ratio between cattle dung and water hyacinth was maintained as 50:0, 40:10, 30:20, 20:30, 10:40, 0:50 respectively after every one week). A simple mechanical hand driven mixing unit was developed and installed in the Modified Deenbandhu biogas plant to solve the problems of choking experienced when using lignocellulosic material. It has an axle with four vertical and two horizontal baffles on both side of the centre. The whole unit was installed inside the biogas plant perpendicular to the flow of feed material in the plant having bearings on both sides for ease in rotation. Handle for operating the mixing unit was kept outside the plant. The speed of rotation was 4 rpm as shown in figure 5.
2 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0
WH CD
10 15 20 25 30 35 40 45 50 55 60 65 70 Days
Figure 6: Biogas production in m3 from the water hyacinth and cattle dung ISBN-978-81-932091-2-7
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Methane (%)
80 60 WH
40
CD
20 0
The biogas spent slurry was analyzed for nutrients like nitrogen, phosphate and potash at every 10 day’s interval. Results are presented in figure 9,10and 11 respectively. 2.5 2 Nitrogen (%)
Figure 7 and 8 shows the amount of methane and carbon dioxide content in biogas produced from water hyacinth and cattle dung graphically during digestion process. The maximum and minimum amount of methane content of the biogas produced from the water hyacinth was 68.70% and 45.80% respectively. The average methane content was found to be 63.33%. The maximum and minimum amount of methane content of the biogas produced from the cattle dung was 59.80% and 45.90% respectively. The average methane content was found to be 57.20%. Higher the amount of methane percentage in biogas clearly denotes the quality of biogas, which in turn increases the calorific value of biogas. The maximum and minimum amount of CO2 content of the biogas produced from the water hyacinth was 51.80% and 28.80% respectively. The average CO2 content was found to be 34.19%. Amount of CO2 in biogas reduce the calorific value of biogas. Lower amount of CO2 in biogas produced from water hyacinth indicates the higher calorific value as compare to that of cattle dung.
30
WH
20
CD
0.5
0 10 15 20 25 30 35 40 45 50 55 60 65 70 Days
Figure 8: CO2 percentage in the biogas
30
0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0
40 Days
50
60
70
WH CD
10
10
20
Figure 9: Nitrogen percentage in digested material Nitrogen content of the fresh water hyacinth was found to be 2.16% and after digestion, an increase of 10.18% was observed. Range of the nitrogen content in the digested slurry of water hyacinth was found to be 2.16% to 2.38% and the average nitrogen content was found to be 2.30%. Nitrogen content of the fresh cattle dung was found to be 1.38% and after digestion, an increase of 36.95% was observed. Range of the nitrogen content in the digested slurry of cattle dung was found to be 1.38% to 1.89% and the average nitrogen content was found to be 1.66%. Due to higher value of nitrogen content in fresh water hyacinth than that of cattle dung, it is higher in digested slurry.
Phosphate (%)
CO2 (%)
40
WH CD
10
Figure 7: Methane percentage in the biogas 50
1
0
10 15 20 25 30 35 40 45 50 55 60 65 70 Days 60
1.5
20
30
40 Days
50
60
70
Figure 10: Phosphate percentage in digested material ISBN-978-81-932091-2-7
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1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0
WH CD 10
20
30
40 50 Days
60
70
Figure 11: Potash percentage in digested material Phosphate content of the fresh water hyacinth was found to be 0.58% and after digestion, an increase of 15.51% was observed. Range of the phosphate content in the digested slurry of water hyacinth was found to be 0.58% to 0.67%, the average phosphate content was found to be 0.63%. Phosphate content of the fresh cattle dung was found to be 0.52% and after digestion, an increase of 19.23% was observed. Range of the phosphate content in the digested slurry of cattle dung was found to be 0.52% to 0.62% and the average phosphate content was found to be 0.57%. Potash content of the fresh water hyacinth was found to be 1.63% and after digestion, an increase of 4.29% was observed. Range of the potash content in the digested slurry of water hyacinth was found to be 1.63% to 1.70%, the average potash content was found to be 1.66%. Potash content of the fresh cattle dung was found to be 0.55% and after digestion, an increase of 47.27% was observed. Range of the potash content in the digested slurry of cattle dung was found to be 0.55% to 0.81%, the average potash content was found to be 0.70%. 4.
Conclusion In this study, an attempt has been made to utilize an obnoxious aquatic weed, water hyacinth. It is a serious hazard to various lakes, ponds or any other stagnant water body. This study has determined the potential of generation of biogas after a microbial pre-treatment, which
will help to sort out the problems of aquatic weed disposal, waste management, sanitation, cooking fuel, fuel for lightening, organic manure production etc. The biogas production from the water hyacinth was 1.92% more than that of cattle dung but the methane content of the biogas from the water hyacinth was 10.71% higher than that of cattle dung. After biogas production, biochemical analysis of the digested slurry was done which concludes that the average NPK content of the digested slurry of water hyacinth was 38.55%, 10.52% and 137.14% more than that of digested slurry of cattle dung respectively. References 1. Ali, N., Chaudhary, B.L. and Khandelwal, S.K. 2004. Better use of water hyacinth for fuel, manure and pollution free environment. Indian Journal of Environmental Protection 24 : 297-303. 2. Ali, N., Chaudhary, B.L. and Panwar, N.L. 2014. The fungal pre-treatment of maize cob heart and water hyacinth for enhanced biomethanation. International Journal of Green Energy 11 : 40-49. 3. Bak, J.S., Ko, J.K., Choi, I.G., Park, Y.C., Seo, J.H. and Kim, K.H. 2009. Fungal pretreatment of lignocellulose by Phanerochaete chrysosporium to produce ethanol from rice straw. Biotechnology and Bioengineering 104 : 471-82. 4. Biogas Technology Development Division. Ministry of New and Renewable Energy. (http://mnre.gov.in/schemes/decentralizedsystems/schemes-2/). 5. Deshmukh, S. and V.R. Deshmukh, V.R. 2013. Bio-efficiency of mushroom on different agro-waste. PKV Research Journal 37 : 50-52. 6. Fadairo, A.A. and Fagbenle, R.O. 2014. Biogas production from water hyacinth blends. In : 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics held at Orlando, Florida, U.S.A. during July 14-16, 2014, pp. 792799. ISBN-978-81-932091-2-7
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7.
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Frezina, N.C.A. 2013. Water hyacinth as a substrate for plant-microbial fuel cell to clean water and produce electricity in marshes. International Journal of Scientific & Engineering Research 4 : 1297-1312. Harley, L.S., Julien, M.H., and Wright, A.D. 1997. Water Hyacinth: A tropical worldwide problem and methods for its Control. In : Proceedings of the First Meeting of the International Water Hyacinth Consortium held at World Bank, Washington during March 18-19, 1997. Jayaweera, M.W., Dilhani, J.A., Kularatne, R.K. and Wijeyekoon, S.L. 2007. Biogas production from water hyacinth (Eichhornia crassipes) grown under different nitrogen concentrations. Journal of Environmental Science and Health. Part A, Toxic/Hazardous Substances and Environmental Engineering 42 : 925-932. Lancer, L. and Krake, K. 2002. Aquatic weeds and their management. International Commission on Irrigation and Drainage 1 : 22-57. Njogu, P., Kinyua, R., Muthoni P. and Nemoto Y. 2016. Biogas production using water hyacinth (Eicchornia crassipes) for electricity generation in Kenya. Energy and Power Engineering 7 : 209-216. Patel, S. 2012. Threats, management and envisaged utilizations of aquatic weed Eichhornia crassipes: An overview. Reviews in Environmental Science and Biotechnology 11 : 249–259. Sawatdeenarunat, C., Surendra, K.C., Takara, D., Oechsner, H. and Khanal, S.K. 2015. Anaerobic digestion of lignocellulosic biomass: Challenges and opportunities. Bioresource Technology 178 : 178-186. Singh, D. and Chen, S. 2008. The white-rot fungus Phanerochaete chrysosporium: conditions for the production of lignindegrading enzymes. Applied Microbiology and Biotechnology 81 : 399-417. Tellez, T., Lopez, E., Granado, G., Perez, E., Lopez, R., and Guzman, J. 2008. The
water hyacinth, Eichhornia crassipes: An invasive plant in the Guadiana River Basin (Spain). Aquatic Invasions 3 : 42-53. 16. Xing, J., Criddle, C. and Hickey, R. 1997. Effects of a long-term periodic substrate perturbation on an anaerobic community. Water Research 31 : 2195-2204. 17. Zhang, Y., Zhang, D., Barrett, S., 2010. Genetic uniformity characterizes the invasive spread of water hyacinth (Eichhornia crassipes), a clonal aquatic plant. Molecular Ecology 19 : 1774-1786.
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Effect of Viscosity in Biomechanics for the Fluid: A Review Vinod Kumar Bais1 and Ankur Kulshreshtha2 1 Manav Bharti Universty, Solan, HP, India. 2 GEC, Banswara, Rajasthan, India. Corresponding Author: Ankur_kulshreshtha@yahoo.in Abstract: The viscosity of a liquid is the correlation of shear stress and velocity gradient. It is the quantity of force need to obtain that substance moving in circular tube. Mathematical techniques are used to find various types of viscosity for fluid and obtain the result with the numerical example to discuss the feature for multiple applications in biomechanics. Key Terms: Shear stress, Mathematical Model, Fluid Dynamics, Viscosity. 1. Introduction: Biomechanics focuses on the application of mechanics in the field of living organism for human development. The biomechanics of human beings is a main part of kinesiology. In this regard, construction of mathematical model to solve the problems of the biomechanics of the human skeleton and its various body parts and other biomaterials like artificial blood vessel and so on. The viscosity of a fluid is a measure of its resistance to gradual deformation by shear stress. It is the force per unit area, therefore the viscosity is equal to force divided by the area. In medical field, the viscosity is a direct measurement of the blood to flow through the blood vessels. Also, the study the stress, we focus on the length and diameter of the vessels. Bessonov N. et. al. 2016 discussed methods of blood flow modeling that blood assumed as a heterogeneous fluid and analysis rheology and non-Newtonian properties. The constructive model for incompressible viscous fluids based on the assumption that the extra stress tensor is proportional to the symmetric part of the velocity gradient, đ?&#x153;? = 2đ?&#x153;&#x2021;đ??ˇ. Where Îź is the viscosity and đ??ˇ = â&#x2C6;&#x2021;đ?&#x2018;˘ + â&#x2C6;&#x2021;đ?&#x2018;˘ /2 is the rate of the deformation tensor. Also, analyze an equilibrium stage of blood vessel and internal blood pressure by the Newton method. Alexander R. McN. Has worked on modeling approaches in biomechanics in 2003. In this work, conceptual models, physical models and
mathematical models has been provided for the study of folding mechanism of insect wings and study the pattern and behavior of the wings and leg muscles. Boda M.A. et. al. 2015 has provided the analysis of kinematic viscosity for high and low sticky liquids at different level of temperature. Nithiarasu P. published his book â&#x20AC;&#x153;Biofluid Dynamicsâ&#x20AC;?, in which there are sufficient theoretically information about the biofluids and many other solving techniques to find Stress and strain and other terms. Kim B. H. et. al 2013 has worked on effect of the fluid viscosity on the liquid- feeding flow phenomena of a female mosquito. The study is focused on the feeding mechanism and viscosity of the fluids in food canal. Sanjeev Kumar et. al. 2009 discussed the effect of porous parameter for the blood flow in a time dependent stenotic artery and to find the stress and pressure on wall, used the Navier-Stokes and the continuity equations. 2. Mathematical Models: Model 1: Kinematic Viscosity It is the measure of the inherent resistance of a fluid to flow when no external force is exerted, except gravity. Mathematically, it can be calculated by dividing the absolute viscosity of a liquid with the liquid mass density. It is denoted by ν and defined as đ?&#x153;&#x201A; đ?&#x153;&#x2C6;= đ?&#x153;&#x152; ISBN-978-81-932091-2-7
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Where đ?&#x153;&#x2C6; = đ??žđ?&#x2018;&#x2013;đ?&#x2018;&#x203A;đ?&#x2018;&#x2019;đ?&#x2018;&#x161;đ?&#x2018;&#x17D;đ?&#x2018;Ąđ?&#x2018;&#x2013;đ?&#x2018;? đ?&#x2018;&#x2030;đ?&#x2018;&#x2013;đ?&#x2018; đ?&#x2018;?đ?&#x2018;&#x153;đ?&#x2018; đ?&#x2018;&#x2013;đ?&#x2018;Ąđ?&#x2018;Ś đ?&#x153;&#x201A;= đ??ˇđ?&#x2018;Śđ?&#x2018;&#x203A;đ?&#x2018;&#x17D;đ?&#x2018;&#x161;đ?&#x2018;&#x2013;đ?&#x2018;?đ?&#x2018; đ?&#x2018;&#x2030;đ?&#x2018;&#x2013;đ?&#x2018; đ?&#x2018;?đ?&#x2018;&#x153;đ?&#x2018; đ?&#x2018;&#x2013;đ?&#x2018;Ąđ?&#x2018;Ś and đ?&#x153;&#x152; = đ??šđ?&#x2018;&#x2122;đ?&#x2018;˘đ?&#x2018;&#x2013;đ?&#x2018;&#x2018; đ??ˇđ?&#x2018;&#x2019;đ?&#x2018;&#x203A;đ?&#x2018; đ?&#x2018;&#x2013;đ?&#x2018;Ąđ?&#x2018;Ś. For example: Obtain the kinematic viscosity, for a liter of mercury with weight 1.95 Kg. Solution: Here, first find the density mass of mercury. . Density of mercury (đ?&#x153;&#x152;) = = = .
= 1950 Since the dynamic viscosity of the mercury (đ?&#x153;&#x201A;) = 1.526 Pa*s. Now the kinematic viscosity is calculated by the formula: đ?&#x153;&#x2C6;= .
đ?&#x153;&#x201A; 1.526 Pa â&#x2C6;&#x2014; s 1.526 N â&#x2C6;&#x2014; s/đ?&#x2018;&#x161; = = đ??žđ?&#x2018;&#x201D; đ??žđ?&#x2018;&#x201D; đ?&#x153;&#x152; 1950 1950 đ?&#x2018;&#x161; đ?&#x2018;&#x161; = 0.00078256 đ?&#x2018;&#x161; /đ?&#x2018; Model 2: Dynamic Viscosity with Tangential Force It is the tangential force required to move one horizontal plane of a fluid with respect to another plane. It is denoted by đ?&#x153;&#x201A; and defined as đ?&#x153;? đ?&#x153;&#x201A;= đ?&#x203A;ž Where đ?&#x153;&#x201A; = đ??ˇđ?&#x2018;Śđ?&#x2018;&#x203A;đ?&#x2018;&#x17D;đ?&#x2018;&#x161;đ?&#x2018;&#x2013;đ?&#x2018;?đ?&#x2018; đ?&#x2018;&#x2030;đ?&#x2018;&#x2013;đ?&#x2018; đ?&#x2018;?đ?&#x2018;&#x153;đ?&#x2018; đ?&#x2018;&#x2013;đ?&#x2018;Ąđ?&#x2018;Ś , đ?&#x153;?= đ?&#x2018;&#x2020;â&#x201E;&#x17D;đ?&#x2018;&#x2019;đ?&#x2018;&#x17D;đ?&#x2018;&#x;đ?&#x2018;&#x2013;đ?&#x2018;&#x203A;đ?&#x2018;&#x201D; đ?&#x2018;&#x2020;đ?&#x2018;Ąđ?&#x2018;&#x;đ?&#x2018;&#x2019;đ?&#x2018; đ?&#x2018; and đ?&#x203A;ž = đ?&#x2018;&#x2020;â&#x201E;&#x17D;đ?&#x2018;&#x2019;đ?&#x2018;&#x17D;đ?&#x2018;&#x; đ?&#x2018;&#x2026;đ?&#x2018;&#x17D;đ?&#x2018;Ąđ?&#x2018;&#x2019;. For example: Calculate the pressure necessary to move a system of liquid with a shear rate of 0.33 per second and the value of dynamics viscosity is 0.019 Pa*s. Solution: To find the pressure (stress), use dynamics viscosity formula đ?&#x153;&#x201A; = => đ?&#x153;? = đ?&#x153;&#x201A; â&#x2C6;&#x2014; đ?&#x203A;žâ&#x20AC;Śâ&#x20AC;Śâ&#x20AC;Ś.(1) đ?&#x153;&#x2C6;=
Where đ?&#x203A;ž = 0.33 đ?&#x2018;?đ?&#x2018;&#x2019;đ?&#x2018;&#x; đ?&#x2018; đ?&#x2018;&#x2019;đ?&#x2018;?đ?&#x2018;&#x153;đ?&#x2018;&#x203A;đ?&#x2018;&#x2018; đ?&#x2018;&#x17D;đ?&#x2018;&#x203A;đ?&#x2018;&#x2018; đ?&#x153;&#x201A; = 0.019 đ?&#x2018;&#x192;đ?&#x2018;&#x17D; â&#x2C6;&#x2014; đ?&#x2018; . Then from equation (1) we get đ?&#x153;? = đ?&#x153;&#x201A; â&#x2C6;&#x2014; đ?&#x203A;ž = (0.019 đ?&#x2018;&#x192;đ?&#x2018;&#x17D; â&#x2C6;&#x2014; đ?&#x2018; ) â&#x2C6;&#x2014; (0.33 đ?&#x2018;?đ?&#x2018;&#x2019;đ?&#x2018;&#x; đ?&#x2018; đ?&#x2018;&#x2019;đ?&#x2018;?đ?&#x2018;&#x153;đ?&#x2018;&#x203A;đ?&#x2018;&#x2018;) đ?&#x153;? = 0.00627 đ?&#x2018;&#x192;đ?&#x2018;&#x17D; = 0.00627 đ?&#x2018; /đ?&#x2018;&#x161; Model 3: Viscosity, Shear Stress and Shear Rate Fluid mechanics of polymers are modeled as steady flow in shear flow. Shear flow can be measured with pressures in the fluid and a resulting shear stress.
Shear flow is defined as flow caused by tangential movement. This imparts a shear stress on the fluid. Shear rate is a ratio of velocity and distance and has units per second. It is defined as đ?&#x203A;žĚ&#x2021; = .đ?&#x2018;&#x161; = = (đ?&#x2018; ) Where h is the distance between two layer of tube and đ?&#x2018;Ł is the velocity of upper layer. Shear stress is proportional to shear rate with a viscosity constant or viscosity function. Shear Stress is defined as đ?&#x153;? = (đ?&#x2018; /đ?&#x2018;&#x161; ) Where F is force applied on the area (A) of the tube. 3. Result and Conclusion: Biomechanics is used to explanations of the mechanical behavior of living organisms. Also, there is an important to understand the basic relationship between stress and strain. It has many mathematical techniques to construct the model for the study of mechanical behavior like pressure and stress of vessel of human body as shown in the figure.
Source: Book Bio fluid Dynamics Biomechanics has advantage of engineering principles and requires understanding of mathematical modeling, mechanics and biology. We have discussed some model with numerical examples to find various factors as shear stress, shear rate, and viscosity. It has play an important ISBN-978-81-932091-2-7
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role in the field of medical sciences specially in orthopedics and obtains a good joint implication, it is also optimizing the different shape of implants so they may better resist extreme a long time mechanical demands in medical field. In this field shear stress, shear rate, viscosity is the important tools for designing the new shapes of various fluid tube and various parts of skeleton and so on and provide a new way to researchers, mechanical manufactures and software designer to develop existing and new shapes. References: 1 N. Bessonov (et. al.) “Methods of blood flow modeling”, Math. Model. Nat. Phenom. Vol. 11, No. 1, 2016, pp. 1-25 2 R. McN. Alexander, “Modelling approaches in biomechanics”, The Royal Society, UK, 6 August, 2003. 3 P. Nithiarasu, published his book Bio fluid Dynamics, UK. 4 M A Boda (et. al.) “Analysis of Kinematic Viscosity for Liquids by Varying Temperature”, IJIRSET, Vol. 4, Issue 4, April 2015 5 Bo Heum Kim (et. al.) “Effect of fluid viscosity on the liquid-feeding flow phenomena of a female mosquito”, The Journal of Experimental Biology 216, 952-959, 2013. 6 Sanjeev Kumar, Archana Dixit, “Effect of Porous Parameter for the Blood Flow in a time Dependent Stenotic Artery”, Indian Journal of Biomechanics: Special Issue (NCBM 7-8 March 2009).
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Thermodynamic investigation on biomass derived syngas fueled combined cycle power plant Mohd Parvez, Abdul Khaliq Department of Mechanical Engineering, Al-Falah University, Faridabad (Haryana) India Mechanical Engg. Dept., King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia Corresponding Author: mparvezalig@rediffmail.com
Abstract This article reports the results of syngas fueled combined power cycle which was analyzed from both energy and exergy point of views. A parametric investigation was carried out to ascertain the effects of change in biomass material, gas turbine inlet temperature, and steam turbine inlet pressure on performance of the biomass gasifier integrated combined cycle plant. The results obtained clearly reveal that first law efficiency and second law efficiency of the combined cycle significantly vary with the change in gas turbine inlet temperature and steam turbine inlet pressure but the change in biomass material shows small variation in these parameters. Keywords: combined cycle, thermo-chemical equilibrium, gasification, syngas, power generation Corresponding author:
1. Introduction The energy and environment norms regarding the ozone layer depletion and the global warming are becoming more and more stringent in almost all over the world. In this challenging scenario, biomass gasification energy for producing electricity gaining popularity, because they use zero global warming and ozone depletion. However, these systems have lower efficiency than the conventional power plants and need optimization from thermodynamic point of view. Direct combustion of biomass is worsened by heterogeneous composition of waste biomass leading to unacceptable consequences because it has low efficiency and a high environmental impact, due to the unburned hydrocarbons and the release of particulates matter. Gasification of biomass is an attractive technology for power generation. The use of biomass gasification process is a key element in an advanced gas turbine combined cycle system. Various investigations based on conventional first – law of thermodynamic method have been carried out in the past on biomass integrated gasification combined cycle. These investigations laid a foundation for the proper utilization of biomass using gasification
technology effectively. Marcio [1] proposed a thermodynamic methodology for the viability of a power generating system based on atmospheric gasification of sugarcane bagasse using fluidized- bed gasifier. In this study various configurations of the power unit were tried until the most efficient was found. Ciferno and Marano [2] reported benchmarking biomass gasification technology for fuels, chemicals and hydrogen production. Larson et al. [3] carried out the cost benefit assessment of biomass gasification power generation in the pulp and paper industry. De Souza Santos [4] described a theory of solid fuels combustion and gasification. The material reported has been found of much use for the analysis of solid fueled power generation system simultaneously involved in the processes of gasification and combustion. Most of the studies reported in the literature as discussed above are based on first law analysis or energy balance approach. First – law of thermodynamics simply deals with the conversion of energy from one form to another. It fails to identify and quantify the sources of thermodynamic losses which are responsible to deteriorate the performance of thermal energy systems and cannot answer why the actual operational performance of energy system differ ISBN-978-81-932091-2-7
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from the design one. In order to overcome with these limitations of the first law, second law of thermodynamics has been adopted by many investigators for the last decade and it is observed that combined application of first and second laws of thermodynamics results to provide credible information about the real performance of thermal power generation systems [5]. Wu et al. [6] carried out first law simulation for 450 kW gas engine using fluidized bed gasifier and reported that its overall efficiency can be achieved 26-28%. For rice husk and agricultural waste plant they found gasifier as the major source of exergy losses. Brown et al. [7] addresses the issues of thermo economic assessment of wood gasification for electricity generation. They identified the operating conditions for maximum exergy efficiency of the plant with minimal investment cost. Bhattacharya et al. [8] conducted a thermodynamic analysis of biomass integrated gasification combined cycle considering the combustion of supplementary biomass fuel using the oxygen available in gas turbine exhaust. There results show the plant efficiencies increase with the increase in both pressure and temperature ratios: however, the latter has a stronger influence than the former. Srinivas et al. [9] predicted the thermal performance of a biomass based IGCC plant and examined the effects of gasifier conditions on the efficiency and power generation capacity of the plant as well as their effect on NOX and CO2 emissions. Most recently theoretical investigations on different biomass material gasification at ambient conditions for gas turbine power generation have also been presented for various operating conditions [10-12]. In this context the current study has been carried out to evaluate the thermodynamic performance of various biomass fueled combined gas - steam cycle for power generation. The effect of change in biomass material and some influenced thermodynamic parameters have been observed on the first law and second law performance of the proposed cycle.
2. Problem formulation Figure 1 shows a thermo â&#x20AC;&#x201C; chemical model of biomass gasification combined power cycle power plant. The biomass fed to the gasifier. The compressed air at state 2 and saturated steam at state 4 enter the gasifer where syngas is produced and goes to the combustion chamber after passing through a gas cleanup unit where tar and char removed. In combustion chamber the chemical reaction are taking place. The products of combustion go to the gas turbine where they expand and produce power. The exhaust gasses of gas turbine enter the heat recovery steam generator (HRSG) where superheated steam is produced. This superheated steam is used to run the steam turbine and produce electric power and exhaust steam from steam turbine routed to the condenser where its phase changes from vapor to liquid and then pumped back to the HRSG. The waste gases available at the exit of HRSG discharge to the atmosphere at ambient pressure. The analysis was carried out as per the assumptions taken by Wu et al. (2008) [6]
3. First and second law analyses of a combined power cycle The gasification reactions in the gasifier are explain as C H O N +wH O + a (O + 3.76N ) +a H O = b CH + b CO + b CO + b H + b H O + b N (1) The syngas obtained after gasification was used in combustion chamber as a fuel reported as
đ?&#x2018;? đ??śđ??ť + đ?&#x2018;? đ??śđ?&#x2018;&#x201A; + đ?&#x2018;? đ??śđ?&#x2018;&#x201A; + đ?&#x2018;? đ??ť + đ?&#x2018;? đ??ť đ?&#x2018;&#x201A; + đ?&#x2018;? đ?&#x2018; + đ?&#x2018;&#x17D; (đ?&#x2018;&#x201A; + 3.76đ?&#x2018; ) = đ?&#x2018;? đ??śđ?&#x2018;&#x201A; + đ?&#x2018;? đ??ť đ?&#x2018;&#x201A; + đ?&#x2018;? đ?&#x2018; (2) The composition of syngas formed after gasification of biomass was computed after following the model developed by Bhattacharya et al. [8]. The thermodynamic performance parameters for the first and second law efficiency of the proposed combined cycle were calculated after using ISBN-978-81-932091-2-7
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đ?&#x153;&#x201A; = Ě&#x2021;
Ě&#x2021;
Ě&#x2021;
Ě&#x2021;
(3)
Ě&#x2021;
đ?&#x153;&#x201A; = Ě&#x2021;
Ě&#x2021;
Ě&#x2021; Ě&#x2021;
Ě&#x2021;
,
(4)
4. Results and discussion The present study is carried out to identify the effect of various influenced parameters on the performance of the integrated gasification combustion chamber in the range of operation, gas turbine inlet temperature (1273 â&#x20AC;&#x201C;1473K), turbine inlet pressure (30 bar to 70 bar) and approach temperature (288 K). The proposed model developed in this paper for solid waste, rice husk and sugarcane bagasse are tested by comparing the result with the published papers of relevant researchers [12]. Figs. 2-3 shows the variation of first and second law efficiencies of biomass gasification of combined power cycle with the change in gas turbine inlet temperature. In general, second law efficiencies of combined are slightly lower than their first law efficiencies. This is due to the fact that the chemical exergy of biomass fuel which is considered as the input in second law analysis is higher than the calorific value of the fuel which is considered as the input in the first law analysis. Figs. 2-3 reveal that both first law and second law efficiencies increase linearly as gas turbine inlet temperature for all three cases of biomass considered. It is further noticed that both first and second law efficiencies of combined power cycle are higher for solid waste and lower for sugarcane bagasse. This is due to the fact that gasifier temperature and lower heating value of syngas is higher in case of solid waste and lower in case of sugarcane bagasse. Figs. 4-5 shows the variation of first and second law efficiencies of combined power cycle with the change in steam turbine inlet pressure. It is found that both first and second law efficiencies decrease with the increase in steam turbine inlet pressure. The reason for this kind of trend is that increase in steam turbine inlet pressure results in lower mass flow rate of steam produced in the HRSG which in turn reduces the steam output
and hence decreases the overall efficiency of the cycle. Since the contribution of gas turbine towards the overall power generation is much higher and is three times larger than the contribution of the steam turbine, and change in steam turbine pressure only effects the steam turbine output not the gas turbine output, therefore, first law efficiency of combined power cycle slightly drops with the increase in steam turbine inlet pressure. For the similar reasons, second law efficiency also drops slightly with the same. 5. Conclusions The proposed biomass derived syngas fueled combined power cycle was analyzed by using first and second law of thermodynamics. The performance of the system was examined under the variation of gas turbine and steam turbine. The main conclusions drawn from this study can be summarized as follows: ď&#x201A;ˇ Both first and second law efficiencies increases considerably with the rise of gas turbine inlet temperature. First law efficiency has been found maximum for solid waste and minimum for sugarcane bagasse. ď&#x201A;ˇ Second law efficiency also increases significantly with the increase in gas turbine inlet temperature and it was maximum for solid waste and minimum for sugarcane bagasse fueled cycle. ď&#x201A;ˇ Both first and second law efficiencies decrease significantly with the increase in steam turbine inlet pressure.
Nomenclature đ?&#x2018;&#x160;Ě&#x2021; ΡI ΡII Ď&#x2020; 1-8 a-e
power (KW) first law efficiency second law efficiency exergy ratio state points of Brayton cycle state points of the steam cycle
References [1] Marcio L.de Souza â&#x20AC;&#x201C; Santos. A feasibility study of an alternative power generation system based on biomass gasification / gas turbine conceptâ&#x20AC;?. Fuel 1999; 78: 529-538. ISBN-978-81-932091-2-7
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[2] Ciferno J.P, Marano J.J. Benchmarking biomass gasification technologies for fuels, chemicals and hydrogen production. U.S Department of Energy National Energy Technology Laboratory 2002. [3] Larson E.D, Consonni S, Katofsky R.E. A cost-benefit assessment of biomass gasification power generation in the pulp and paper industry. Energy Group Publications, Princeton University, Princeton, NJ 2003. [4] Marcio L. de Souza-Santos. Solid fuels combustion and gasification: modeling, simulation and equipment operations”. CRS Press, Taylor & Francis Group 2010. [5] Dincer I, Rosen M.A. Exergy. 2nd edition, Elsevier; New York 2012. [6] Wu C, Yin X, Ma L, Zhou Z and Chen H. Design and operation of a 5.5 MWe biomass integrated gasification combined cycle demonstration plant”. Energy & Fuels 2008; 22: 4259-4264. [7] Brown D, Gassner M, Fuchino T, Marechal F. Thermo-economic analysis for the optimal conceptual design of biomass gasification energy conversion systems. Applied Thermal Engineering 2009; 29: 2137-2152. [8] Bhattacharya A, Manna D, Paul B, Datta A. Biomass integrated gasification combined cycle power generation with supplementary biomass firing: Energy and exergy based performance analysis. Energy 2011; 36 (5), pp 2599-2610. [9] Srinivas T, Reddy B.V and Gupta A.V.S.S.K.S. Thermal performance prediction of a biomass based integrated gasification combined cycle plant. Journal of Energy Resources Technology 2012; Vol. 134/ 0210021-021002-9. [10] Saeidi S, Mahmoudi SMS, Nami H, Yari M. Energy and exergy analyses of a novel near zero emission plant: Combination of MATIANT cycle with gasification unit. Applied Thermal Engineering 2016; 108: 893-904. [11] Athari H, Soltani S, Rosen M, Mahmoudi SMS, Morosuk T. A comparative exergoeconomic evaluation of biomass post-
firing and co-firing combined power plants. Biofuels 2017; 8 (1): 1-15. [12] Parvez M. Investigation on thermodynamic behavior of apple juice waste and sugarcane bagasse gasified fuelled combined cycle power generation system”. Biofuels 2017; http://dx.doi.org/10.1080/17597269.2017.1374 768. 4 5
Gas Cleaner Unit
Com Comb busti ustion
Gasif Gasifi ier er 2
3
e St Ste ea am Tu
7
H H R R S S G G
G Ga sas
Bioma ss
b 3
a
6
Comp 1 ressor
2 Cond c enser d Feed
8 A i
To Stack Gases to Atmosphere
Figure 1 Schematic diagram of biomass fueled combined power cycle plant 41
First law efficiency of Solid waste
40
First law efficiency for Rice husk
39 38 37 36 35 34 33 32 1250
1300
1350
1400
1450
1500
Figure 2 Variation of first law efficiency with turbine inlet temperature of combined power cycle ISBN-978-81-932091-2-7
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40
Second law efficiency of Solid waste Second law efficiency of Rice husk
38 36 34 32 30 28 1250
1300
1350
1400
1450
1500
Figure 3 Variation of second law efficiency with turbine inlet temperature of combined power cycle
39
First law efficiency of Solid waste
38 37 36 35 34 33 32 30
40
50
60
70
80
Figure 4 Variation of first law efficiency with pressure ratio of combined cycle power cycle Second law efficiency of Solid waste Second law efficiency of Rice husk
39 38 37 36 35 34 33 32 31 30 30
40
50
60
70
80
Figure 5 Variation of second law efficiency with pressure ratio of combined cycle power cycle ISBN-978-81-932091-2-7
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Bio Fuel: Need for the sustainable Generation Sunil Sharma, Vishnu Inani Department of Electronics & Communication Engg, Pacific University, Udaipur Corresponding Author: ersharma.sunil@gmail.co, vishnuinani77@gmail.com INTRODUCTION Bioenergy is energy derived from biofuels. Biofuels are fuels produced directly or indirectly from organic material – biomass – including plant materials and animal waste. Overall, bioenergy covers approximately 10% of the total world energy demand. Traditional unprocessed biomass such as fuelwood, charcoal and animal dung accounts for most of this and represents the main source of energy for a large number of people in developing countries who use it mainly for cooking and heating. More advanced and efficient conversion technologies now allow the extraction of biofuels from materials such as wood, crops and waste material. Biofuels can be solid, gaseous or liquid, even though the term is often used in the literature in a narrow sense to refer only to liquid biofuels for transport. Biofuels may be derived from agricultural crops, including conventional food plants or from special energy crops. Biofuels may also be derived from forestry, agricultural or fishery products or municipal wastes, as well as from agro-industry, food industry and food service by-products and wastes. A distinction is made between primary and secondary biofuels. In the case of primary biofuels, such as fuelwood, wood chips and pellets, organic materials are used in an unprocessed form, primarily for heating, cooking or electricity production. Secondary biofuels result from processing of biomass and include liquid biofuels such as ethanol and biodiesel that can be used in vehicles and industrial processes. Bioenergy is mainly used in homes (80%), to a lesser extent in industry (18%), while liquid biofuels for transport still play a limited role (2%) TYPES OF LIQUID BIOFUELS The most widely used liquid biofuels are ethanol and biodiesel. Ethanol is a type of alcohol that can be produced using any feedstock containing significant amounts of sugar, such as sugar cane or sugar beet, or starch, such as maize and wheat. Sugar can be directly fermented to alcohol, while starch first needs to be converted to sugar. The fermentation process is similar to that used to make wine or beer, and pure ethanol is obtained by distillation. The main producers are Brazil and the USA. Ethanol can be blended with petrol or burned in nearly pure form in slightly modified spark-ignition engines. A liter of ethanol contains approximately two thirds of the energy provided by a liter of petrol. However, when mixed with petrol, it improves the
combustion performance and lowers the emissions of carbon monoxide and sulphur oxide. Biodiesel is produced, mainly in the European Union, by combining vegetable oil or animal fat with an alcohol. Biodiesel can be blended with traditional diesel fuel or burned in its pure form in compression ignition engines. Its energy content is somewhat less than that of diesel (88 to 95%). Biodiesel can be derived from a wide range of oils, including rapeseed, soybean, palm, coconut or jatropha oils and therefore the resulting fuels can display a greater variety of physical properties than ethanol. SECOND-GENERATION BIOFUELS Currently used liquid biofuels, which include ethanol produced from crops which is
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containing sugar and starch and biodiesel from oilseeds, are referred to as first-generation biofuels. These fuels only use a portion of the energy potentially available in the biomass. Most plant matter is composed of cellulose, hemicellulose and lignin, and “secondgeneration biofuel” technologies refer to processes able to convert these components to liquid fuels. Once commercially viable, these could significantly expand the volume and variety of sources that could be used for biofuel production. Potential cellulosic sources include municipal waste and waste products from agriculture, forestry, processing industry as well as new energy crops such as fast-growing trees and grasses. As a result second generation biofuel production could present major advantages in terms of environmental sustainability and reduced competition for land with food and feed production. It could also offer advantages in terms of greenhouse gas emissions. Various techniques are currently being developed to produce second generation biofuels. However, it is uncertain when such technologies will enter production on a significant commercial scale. The conversion
from
cellulose to ethanol involves
two steps.
The cellulosic and
cellulosic
hemi
components of the plant material are first broken down into sugars, which are then fermented to obtain ethanol. The first step is technically difficult, although research continues on developing efficient and cost-effective ways of carrying out the process. Lignin cannot be converted to ethanol, but it can provide the necessary energy for the conversion process. Current world oil demand amounts to about 4000 Million tonnes of oil equivalent (Mtoe) While the productionof liquid biofuels amounts to 36 More representing less than 1% of this world demand.
Around 85% of the liquid biofuels are currently produced in the form of bioethanol with the main producers being Brazil and the USA. Biodiesel production is essentially concentrated in the European Union. Large-scale production of biofuels from crops requires large land areas to grow them, which generates increasing competition for natural resources, notably land and water. Crop yields per hectare vary widely depending on the type of crop, the country and the production system. Currently, ethanol production from sugar cane and sugar beet produces the highest yields per hectare. DRIVERS OF BIOFUEL POLICIES The main drivers behind government support for biofuels in OECD countries are concerns about climate change and energy security, and the political will to support the farm sector through increased demand for agricultural products. Energy Security Secure access to energy is a longstanding concern in many countries. The recent increases in oil and other energy prices have increased the incentive to promote alternative sources of energy. Strong demand from rapidly developing countries, especially China and India, is adding to concerns over future energy prices and supplies. The transport sector depends mainly on oil. Liquid biofuels represent the main alternative source that can supply fuels suitable for use in current vehicles, without radical changes to transport technologies. Climate change There is increasing concern about human-induced climate change, and the effects of greenhouse gas emissions on rising global temperatures. Bioenergy is often seen as a way to reduce greenhouse gas emissions.
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policy measures are influencing biofuel development? Policies on agriculture, energy, transport, environment and trade all have an influence on biofuel production. Schemes to promote and support biofuels have been introduced both in OECD and developing countries. Without these incentives, widespread biofuel production would in most cases not have been commercially viable.
prices of biofuels and provide an incentive for domestic
The policies used by governments to promote and support biofuel development include various instruments. They can support the biofuel supply chain at different stages.
sources.
o Agricultural policies existed well before the introduction of biofuels. They include agricultural subsidies and price support mechanisms
which
directly
production. Tax incentives or penalties are among the most widely used instruments for stimulating demand for biofuels and can drastically affect the competitiveness of biofuels compared to other energy o
o Research and development is generally aimed at improving the efficiency and costeffectiveness of biofuel production, and identifying sustainable feedstocks. In developed countries an increasing proportion of public research and development funding is directed towards
affect
production levels and prices of biofuel crops as well as production systems and methods. These policies also have implications at international level for agricultural trade and geographical pattern of agricultural production. Blending mandates defining the overall amount or proportion of biofuel that must be blended with petrol and diesel are o
increasingly being imposed. Subsidies and support for the distribution and use of biofuels are key policy components in most countries that promote the use of biofuels. Several countries are subsidizing or mandating investments in infrastructure for biofuel storage, transportation and use, especially towards bioethanol which requires major investments in equipment. o
Tariffs or import barriers are duties usually imposed on imported goods. They are widely used on biofuels to protect the national agriculture and biofuel sectors, support domestic o
second-generation biofuel technologies, in particular cellulosic ethanol andbiomass-derived alternatives to petroleum-based diesel. Impacts of biofuel policies on international markets and trade? o assesses the net effect on greenhouse gas emissions of replacing fossil fuels by biofuels, we need to analyse emissions throughout the whole process of producing, transporting and using the ISBN-978-81-932091-2-7
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fuel. Life-Cycle Analysis is the main tool used to do this. It compares a specific biofuel system with a reference system – in most cases petrol. Greenhouse gas balances differ widely depending on the type of crop, on the location, on how feedstock production and fuel processing is carried out. Biofuels from some sources can even generate more greenhouse gas emissions than fossil fuels. A significant factor contributing to greenhouse gas emissions is the amount of fossil energy used for feedstock production and transport, including for fertilizer and pesticide manufacture, for cultivation and harvesting of the crops, and or in the biofuel production plant itself. Emissions of nitrous oxide are another important factor. It is released when nitrogen fertilizers are used and its greenhouse gas effect is about 300 times stronger than that of carbon dioxide. By-products from biofuel production such as proteins for animal feed make a positive contribution to climate change mitigation because they save energy and greenhouse gas emissions that would otherwise have been needed to produce the feed by other means. ENVIRONMENTAL IMPACTS BIOFUEL PRODUCTION
OF
To assess the net effect on greenhouse gas emissions of replacing fossil fuels by biofuels, we need to analyse emissions throughout the whole process of producing, transporting and using the fuel. Life-Cycle Analysis is the main tool used to do this. It compares a specific biofuel system with a reference system – in most cases petrol. Greenhouse gas balances differ widely depending on the type of crop, on the location, and on how feedstock production and fuel processing are carried out. Biofuels from some
sources can even generate more greenhouse gas emissions than fossil fuels. A significant factor contributing to greenhouse gas emissions is the amount of fossil energy used for feedstock production and transport, including for fertilizer and pesticide manufacture, for cultivation and harvesting of the crops, and or in the biofuel production plant itself. Emissions of nitrous oxide are another important factor. It is released when nitrogen fertilizers are used and its greenhouse gas effect is about 300 times stronger than that of carbon dioxide. By-products from biofuel production such as proteins for animal feed make a positive contribution to climate change mitigation because they save energy and greenhouse gas emissions that would otherwise have been needed to produce the feed by other means. Most studies have found that producing first generation biofuels usually yields reductions in greenhouse gas emissions of 20 to 60% when fossil fuels are replaced provided the most efficient systems are used and carbon dioxide emissions from changes in land-use are excluded. CHALLENGES
OF
BIOFUEL
POLICIES Government incentives and support for biofuel production and use have been largely guided by national or regional interests rather than a more global perspective. The desire to support farmers and rural communities has been one of the strongest drivers. There is a need for a more consistent set of policies and approaches, based on a clearer understanding of the economic, environmental and social implications, in order to balance the potential and risks.
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These policies must be formulated in a situation of considerable uncertainty.
fluctuating fossil fuel prices and on policy developments.
o The exact role of biofuels in future global energy o supplies is unknown. Yet even if the contribution of biofuels to global energy supply remains small, it may still imply a considerable impact on agriculture and food security.
Technological developments may also influence their profitability on the medium and long term. For instance, commercial competitiveness of second
o
The future economic viability of biofuels is uncertain, because it depends on REFERENCES 1. Evans, G. "International Biofuels Strategy Project. Liquid Transport Biofuels Technology Status Report, NNFCC 08017", National Non-Food Crops Centre, 2008-04-14. Retrieved on 2011-02-16. 2. "ADEME" (PDF). ADEME. Retrieved 22 September 2015. 3. Oliver R. Inderwildi, David A. King (2009). "Quo Vadis Biofuels". Energy & Environmental Science. 2: 343. doi:10.1039/b822951c 4. Peterson, Andrew (9 July 2008). "Thermochemical biofuel production in hydrothermal media: A review of sub- and supercritical water technologies". Energy & Environmental Science. 1 (1): 32– 65. doi:10.1039/b810100k. 5. Ramirez, Jerome; Brown, Richard; Rainey, Thomas (1 July 2015). "A Review of Hydrothermal Liquefaction Bio-Crude Properties and Prospects for Upgrading to Transportation Fuels". Energies. 8: 6765– 6794. doi:10.3390/en8076765. 6. National Non-Food Crops Centre. "NNFCC Newsletter – Issue 19. Advanced Biofuels", Retrieved on 2011-06-27 7. National Non-Food Crops Centre. "Review of Technologies for Gasification of Biomass and Wastes, NNFCC 09-008", Retrieved on 2011-06-24 8. R. Inderwildi; David A. King (2009). "Quo vadis biofuels?". Energy Environ. Sci. 2: 343346. doi:10.1039/B822951C. "Refuel.c om biomethanol". refuel.eu.
generation biofuel technologies may significantly improve the prospects for biofuel development. 9.
10.
11.
12.
13.
14. 15.
16.
Knight, R. "Green Gasoline from Wood Using Carbona Gasification and Topsoe TIGAS Processes." DOE Biotechnology Office (BETO) 2015 Project Peer Review (24 Mar 2015). Lu, Yongwu, Fei Yu, Jin Hu, and Jian Liu. "Catalytic conversion of syngas to mixed alcohols over Zn-Mn promoted Cu-Fe based catalyst." Applied Catalysis A: General (2012). Quarderer, George J., Rex R. Stevens, Gene A. Cochran, and Craig B. Murchison. "Preparation of ethanol and higher alcohols from lower carbon number alcohols." U.S. Patent 4,825,013, issued April 25, 1989. Subramani, Velu; Gangwal, Santosh K.; "A Review of Recent Literature to Search for an Efficient Catalytic Process for the Conversion of Syngas to Ethanol", Energy and Fuels, 31 January 2008, web publication. Larry Rother (2006-04-10). "With Big Boost From Sugar Cane, Brazil Is Satisfying Its Fuel Needs". The New York Times. Retrieved 2008-04-28. "Biofuels in Brazil: Lean, green and not mean". The Economist. 2008-06-26. Retrieved 2008-11-28. "Greenhouse Gas Reduction Thresholds". U.S. Environmental Protection Agency. Archived from the original on 2011-11-14. Retrieved 2015-0614. "EPA designates sugarcane ethanol as advanced biofuel". Green Momentum. ISBN-978-81-932091-2-7
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Archived from the original on 2011-07-11. Retrieved 2015-06-14. 17. Garten Rothkopf (2007). "A Blueprint for Green Energy in the Americas". InterAmerican Development Bank. Retrieved 2008-08-22. See chapters
Introduction (pp. 339-444) and Pillar I: Innovation (pp. 445-482)
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Parametric study of Pump as Turbine-1: variation of speed Doshi A. V.; Bade M. H. Mechanical Engineering Department, SVNIT, Surat, Gujarat, India-395007 Corresponding Author: avdoshi2001@gmail.com Abstract Pump operated in reverse mode (PAT) are popular for remote energy source where energy is required mainly for lighting during night hours and may used for local industry during day. However, in Indian situation, flow rate of available water streams are higher in rainy season and reducing toward summer. If speed of PAT is constant then there is significant loss in efficiency due to reduction in flow rate. However, operating the PAT at variable speed, efficiency loss may be significantly reduced. In this paper, simple approach based on characteristics of pump operated in reverse mode and affinity law is used to evaluate the best efficiency point at variable speed conditions. Keywords: Pump as turbine, reverse mode operation of pump, affinity law
1.
Introduction Energy is necessary for holistic development of society and need to be provided to everyone irrespective of paying capacity. Considering challenges of use of fossil fuels such as pollution mainly due to emission of flue gases, climate change due to global warming, etc., renewable energy sources are only the potential source for sustainable development (Derakhshan and Nourbakhsh 2008). Among various renewable energy sources, microhydro power plants are gaining special attention if natural streams are available due to its continuous and reliable feature. Additionally, remote areas which are far away from gridlines, isolated power systems such as micro-hydro power plants are popular, which may take local industrial load during day time and provide electricity for lighting at night hours (Williams 2003). For implementation of micro-hydro power plants major cost is for water turbine, as it need to be designed and developed in meagre quantity. To overcome this issue pump as turbine (PAT) is in use since pumps are mass manufactured and are robust in design as well as construction. Being pump is not manufactured as turbine, it lacks governing mechanism resulting in lower efficiency at part load and over load conditions except best efficiency point (Yang et al. 2012). However, it is always difficult to match best efficiency conditions at field operations due to various influencing factors for efficient operation of PAT. For Indian continent, during monsoon availability of water flow rate and head is very high, but it decreases towards the summer and becomes minimum at start of
monsoon. So designing the PAT for variable flow conditions so that it will give maximum efficiency is essential. Fernandez et al. (Fernández et al. 2004) presented parametric study on a centrifugal pump used as a turbine at various rotational speeds. However, they felt that in order to predict the turbine characteristics accurately it is necessary to analyze statistically more test data to arrive good relations. Yang et al. (2012) carried out experimental work on single stage centrifugal pump operated as a turbine at different rotational speeds (1000, 1200, 1500 and 1800 rpm). Additionally, experimental results are validated with computational work showing agreement and they have concluded that it is more suitable to select a small PAT at large capacity, so that its efficiency will not drop rapidly or become energy-consuming device as flow rate fluctuates. Caravetta et al. (Carravetta et al. 2014) studied the affinity law for the evaluation of the behaviour of a single machine under variable speed. They selected a large database of experimental curves of several PATs (17 PATs) operated at different speeds and compared the experimental data with the results of the application of the affinity law. Further it is concluded that the error in the evaluation of efficiency was less than 15 % for velocities varies from −40 % to +50 %. Jain et al. (2015) carried out experimental investigations on centrifugal pump running in turbine mode to optimize its operational parameter by varying from 900 to 1500 rpm. The performance of PAT was found better at the lower speeds than that at the rated speed. Ismail et al. (2016) conducted study of ISBN-978-81-932091-2-7
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PAT to simulation analysis of the effect of rotational speed on PAT’s performance curve over a range of flow rates using numerical tool. Wang et al. (2016) compared the results obtained by the experiment and by theoretical calculation and observed deviation between them at of best efficiency point for different rotational speed. 1.1 Objectives of the Current Study Based on the above-mentioned literature review and available experimental facility in the laboratory, the following objectives have been planned: i. To operate a selected pump in reverse mode (PAT) and to obtain it’s performance characteristic at various speeds. ii. To find out the optimal operating point (best efficiency point) based on experimental work at various speeds for recommendation of applicability of PAT under various flow conditions. iii. To compare the obtained experimental results of PAT with that of the results deduced by affinity law 2. Means of solutions: The methodology applied for achieving above objectives are experimental investigations and theoretical analysis. 2.1 Experimental Investigation A radial flow type centrifugal pump with the specifications shown in Table 1 is selected to operate as turbine in the test rig (shown in Figure 1). The main components in the PAT test rig are feed pump, piping system, test bed, draft tube, eddy current dynamometer, etc. The high end measuring devices such as pressure transmitters, magnetic flow meter, speed sensors, and torque sensor are employed. Detailed description of this PAT test rig is given by Doshi (2017). The PAT is tested for three different speeds (800 rpm, 900 rpm, and 1000 rpm) and appropriate data is recorded using PLC and SCADA system. This data is processed to plot various characteristic curves such as head Vs. flow rate, power Vs. flow rate and efficiency Vs. flow rate 2.2 Theoretical Analysis of PAT To evaluate PAT parameters at BEP for different speeds, affinity laws are applied. The affinity laws express the mathematical relationship between the variables of PAT at
BEP for different speeds when its diameter is kept constant. These relations are applicable to all class of turbomachines. For small variation of speed of PAT (with constant diameter), variation in different efficiencies such as volumetric, hydraulic and mechanical efficiencies are very small. In addition, velocity triangles at inlet and outlet are assumed to be similar. Therefore, the simplified affinity laws for PAT variables at BEP are: Q1 n1 Q2 n2
(1)
2
H1 n1 H2 n2
(2)
3
P1 n1 P2 n2
(3)
Figure 2 shows velocity triangles at the inlet and exit of the runner blade of a PAT. The relationship between theoretical parameters of PAT can be expressed in terms of different components of velocity triangles. Using momentum theorem and turbine inlet and outlet velocity triangles, Euler head in turbine mode is represented as: (4)
H =
Additionally, for steady state, theoretical flow rate through PAT is given by following equation: Q = πD B C
= πD B C
(5)
Furthermore, shaft power is expressed as: P = ρgQH ∗ η ∗ η ∗ η
(6)
3 Results and Discussions: The data generated by running the same PAT at speed of 800 rpm, 900 rpm and 1000 rpm with help of experimental test rig and evaluated various parameters such as flow rate, head, power, and efficiency. These parameters are shown in the form of characteristic curves as head, power and efficiency Vs. flow rate in Figures 3, 4, and 5. ISBN-978-81-932091-2-7
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In the plot of head Vs. discharge (Figure 3), higher speed curve is above that of lower throughout part load to overload region. The plots are diverged at part region and converging towards overload region. This indicates that higher head is required to operate the PAT at high speed in part load region and for over load region, it is almost converged. The second characteristic curve (Figure 4) indicates that output power at part load is close and diverging towards overload region for given speeds. At higher operating speed of PAT, power output in overload region is also higher. The efficiency curve shown in Figure 5 for speeds 800 rpm, 900 rpm and 1000 rpm indicate that at duty point efficiency of PAT is maximum, in part load, and overload region is dropping. In part load region, the efficiency curve is steep whereas in overload region slop of drop in efficiency curve is comparatively small. With increasing in the speed of PAT, it is observed from Figure 5 that the peak efficiency (BEP) is shifting towards higher flow rate. Further, this helps in operation of PAT where flow rate is reduced. If flow rate is dropped down, then it is always advantageous to operate PAT at lower speed than the speed at which it is running such that it’s operating point for new condition will match with the duty point. Table 2 presents the performance parameters at BEP determined by experiment and by affinity law. The difference between them is negligible as speed range is also comparative small indicating that for small speed range, affinity law held good at BEP. Further, in the given speed range, peak efficiencies are also close as all losses are nearly same and there is similarity in velocity triangles. 4 Conclusions: In the paper, the state of art facility is developed for testing the PATs with high-end instrumentation and automatic control systems. Based on PAT characteristic curves obtained at various speed, PAT can be operated optimally (without much compromise of reduction in efficiency) to meet with variable flow conditions. For low range of speed variations, the affinity law held good and can be used to predict the PAT performance parameters mainly at BEP. Testing of affinity law at high-speed range with large data can be
future scope of work. This will increase the applicability of PAT for variable speed operation. Nomenclatures: B C D g acceleration, m/s2 h H n P Q u velocity, m/s w Greek Symbols α β η ρ ω
Impeller width, m Absolute velocity, m/s Impeller diameter, m Gravitational Head, m Net head, m Rotational Speed in rpm Power, kW Discharge, m3/s Tangential blade Relative velocity, m/s Absolute flow angle, ° Blade angle, ° Efficiency, % Mass density, kg/m3 Angular velocity, rad/s
Abbreviations PLC Programmable Logic Controller rpm revolution per minute SCADA Supervisory Control And Data Acquisition Subscripts 1 mode) 2 mode) h m v u
Impeller inlet (Turbine Impeller exit (Turbine Hydraulic Mechanical volumetric Tangential component
References: 1. Carravetta, A., Conte, M.C., Fecarotta, O., and Ramos, H.M., 2014. Evaluation of PAT performances by modified affinity law. Procedia Engineering, 89, 581–587. 2. Derakhshan, S. and Nourbakhsh, A., 2008. Experimental study of characteristic curves of centrifugal pumps working as turbines in different specific speeds. ISBN-978-81-932091-2-7
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3.
4.
5.
Experimental Thermal and Fluid Science, 32 (3), 800–807. Doshi, A., 2017. Influence of Inlet Impeller Rounding and the Shape of NonFlow Zones on the Performance of Centrifugal Pump As Turbine. Sardar vallabhbhai National Institute of Technology, Surat, India. Fernández, J., Blanco, E., Parrondo, J., Stickland, M.T., and Scanlon, T.J., 2004. Performance of a centrifugal pump running in inverse mode. Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 218 (4), 265–271. Ismail, M.A., Othman, A.K., and Zen, H., 2016. Numerical Investigation of Rotational Speed on Pump as Turbine for Microhydro Applications. Applied Mechanics and Materials, 833, 11–18.
6.
7.
8. 9.
Jain, S. V., Swarnkar, A., Motwani, K.H., and Patel, R.N., 2015. Effects of impeller diameter and rotational speed on performance of pump running in turbine mode. Energy Conversion and Management, 89, 808–824. Wang, T., Kong, F., Chen, K., Duan, X., and Gou, Q., 2016. Experiment and analysis of effects of rotational speed on performance of pump as turbine. Transactions of the Chinese Society of Agricultural Engineering, 32 (15), 67–74. Williams, A.A., 2003. Pumps as Turbines A user’s guide. 2nd Ed. Warwickshire, UK: Practical Action publishing. Yang, S.S., Kong, F.Y., Jiang, W.M., and Qu, X.Y., 2012. Research on rotational speed to the influence of pump as turbine. IOP Conference Series: Earth and Environmental Science, 15 (4), 42023.
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List of Figures: Figure 1: Schematic Layout of PAT Test Rig (Doshi 2017) Figure 2: Velocity triangles at inlet and outlet of PAT Figure 3: Head Vs. Flow Rate characteristic curves for PAT at different speeds Figure 4: Power Vs. Flow Rate characteristic curves for PAT at different speeds Figure 5: Efficiency Vs. Flow Rate characteristic curves for PAT at different speeds
25 800 RPM
20 Head (metre)
15 10 5 0 0
5
10 15 Flow rate (lpm)
20
25
Figure 3: Head Vs. Flow Rate characteristic curves for PAT at different speeds 3 800 RPM
2.5
ElectroMagneticFlowM eter ControlValve
Power (kW)
2 1.5
Pressure Guages
VFD Panel
FeedPump
EddyCurrent Dynamometer
Conrtol Panel G.L.
TorqueSensor
Pressure Guages
0.5
PAT
0 0
M otor
Ground level
1
TestBed
Draft Tube
Comm onSump
Ground level
10 15 Flow rate (lps)
20
25
Figure 4: Power Vs. Flow Rate characteristic curves for PAT at different speeds 70 800 RPM
60 50 Efficiency (%)
Figure 2: Schematic Layout of PAT Test Rig (Doshi 2017)
5
40 30 20 10 0 0
5
10
15 20 Flow rate (lpm)
25
Figure 5: Efficiency Vs. Flow Rate characteristic curves for PAT at different speeds
Figure 2: Velocity triangles at inlet and outlet of PAT ISBN-978-81-932091-2-7
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List of Tables: Table 1: Pump specifications selected for reverse mode operation Table 2: Comparison of experimental and analytical parameters at BEP Table 1: Pump specifications selected for reverse mode operation Property of centrifugal Value pump Head (bep)
20.4 m
Flow rate (bep)
17.5 lps
speed
1450 rpm
Efficiency (bep)
64 %
Impeller diameter
0.260 m
Number of blades
6
Table 2: Comparison of experimental and analytical parameters at BEP Speed rpm
Flow Rate lps
800 900 1000
13.51 14.95 16.77
Head, (m) Efficiency (η) % Experiment Affinity 62.75 62.71 63.35
10.73 13.36 16.67
13.58 16.76
Power, (kW) Experiment
Affinity
0.892 1.228 1.737
1.27 1.742
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Performance Analysis of a Low Price Thermoelectric Cooler: An Experimental Approach Shiv Lal1, Emarti Kumari2 of Mechanical Engineering, Rajasthan Technical University Kota 324010, India 2Department of Mechanical Engineering, Poornima Groups of Institutions, Jaipur, 302022, India Corresponding Author: shivlal1@gmail.com , +91-9636855553 1Department
Abstract In this communication, performance analysis of thermoelectric refrigerator is carried out. The thermoelectric refrigerator is developed in the laboratory and onsite experimental work has been done. The complete system cost is very low approximately 49.66 USD. The COP is varying from 0.17 to 0.26 at different cooling load condition and the lowest temperature can be achieved 2.3 C to 10.5°C without load and full load within 28 minutes, respectively. The material research and cascading of the modules are required to increase the cooling effect as well as capacity of the refrigerator. Key word: Refrigerator; Peltier-Seebeck effect; Thermo-Electric Refrigerator (TER)
1.
Introduction
In present era a new technology is required to meet the refrigeration load of the world, to minimize the utilization of CFC and HFC’s for eco-friendly concern. Peltier effect and Seebeck effect were first discovered to present in metals as early as 1820s–1830s [1]. Beitner [2-3] proposed a simple design of thermoelectric module which can produce heating effect at one side and cooling effect at another side. Reed and Hatcher [4] introduced a fan to enhance the heat dissipation at hot side of TER. The super insulation material and phase change material were introduced by Park [4-5], these materials improved the energy efficiency of the system and extended the time period. Guler and Ahiska [7] experimentally investigated the performance of a portable TER medical cooling kit. Chen [8] analysed the heat transfer rate and efficiency of TE (thermoelectric) cooling systems, and observed a low efficiency. The purpose of a TER is to maintain the junction temperature of an electronic device below a certain temperature by removing heat from the device [9]. Peltier cooling appliances can provide rapid cooling. For example, a solar Peltier refrigerator is capable for reducing the temperature from 27 °C to 5 °C in about 44 minute. TER is a light, rugged, reliable and noiseless medical cooling kit. Dai et al. [10] proposed the merits of the TER as follows: light, reliable, noiseless,
rugged and low cost in mass production, uses electron rather than refrigerant as heat carrier, low starting point and it is feasible to be used solar cells. Astrain et al. [11] developed a computational model based on finite difference method to simulate the thermal and electric performance of thermoelectric refrigerator. Author was observed that thermoelectric refrigerator is more ecological, silent and robust as compare to vapour compression cycle-based refrigerator. Sabah et al. [12] built an affordable solar thermoelectric refrigerator for the desert people of remote area of Oman. That was designed to store and transport the biological material and medications. Author was stated that TER can reduce the temperature of water from 27 C to 5 °C within 44 minute, evaluated the COP of that TER was 0.16. Putra [13] designed, manufactured and tested a portable vaccine carrier box employing thermoelectric module and heat pipe. The heat pipe is working as a heat sink when it fixed at hot side of the TER, it was reported that by heat pipe cooling performance found better than without heat pipe. The temperature in the vaccine carrier has reached up to -10 °C within a hour. It shows that the vaccine carrier can store medicine at any desired temperature. Adeyanju et al. [14] theoretically and experimentally compared the chilling time of water between freezer space of conventional house hold refrigerator and beverages TER and observed ISBN-978-81-932091-2-7
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that the TER reduces temperature exponentially to time as compared to conventional VCR varies linearly. TER gives the fastest cooling as compared to conventional refrigerator. Gillott et al. [15] experimentally investigated a thermoelectric cooling (TEC) devices built in laboratory for small-scale space conditioning applications in buildings. They were find out an optimum solution for operating the TEC. The COP of the TEC was observed by 0.45 for cooling effect of 200 W for which the input current supplied by 4.8A for each module. Thermoelectric refrigerators applications are concerned with environment friendly refrigeration in electronic industry, medical services, space applications, milk industry, transportation tools, and military devices [16]. TER refrigeration devices are a low cost in mass production if charge carriers in the thermoelectric material are used rather than refrigerant as the heat dissipation carrier. Zhou and Yu [2012] presented a generalized theoretical model for the optimization of a thermoelectric cooling system. Their analysis showed that the maximal COP and the maximal cooling capacity can be obtained when the finite thermal conductance is optimally allocated. Ranjana et al. [17] experimentally studied the thermoelectric cooler driven by photovoltaic system. They determined that the unit can maintain 10-15 degree Celsius temperature and revealed COP was 0.34. Authors also stated that the performance of the system is function of solar insolation rate and temperature difference of hot and cold sides of TE modules. Researchers also designed it for personal cooling like for electronic cooling [18]. Twaha et al. [19] reviewed the TER / TEG technology for application, modelling and performance improvement. Hence, to reduce the power consumption rate in urban area; to improve the leaving life of rural area and to save the deteriorating environment due to various refrigerants (CFC and HFC) more research work is required for thermo electric refrigerators / coolers. In this paper, authors have developed a thermo electric refrigerator / cooler that is
operated by solar cells. It is also determined the cooling capacity and coefficient of performance of the developed refrigerator. This system is suitable in rural areas for storage of food and vaccines. So, more experimental and numerical analysis are required for acceptance of this technology. 2.
Materials and Methods: The experimental set-up is developed in Laboratory of Department of Mechanical Engineering, Poornima Groups of Institutions, Jaipur [Latitude and Longitude 26° 55' 19" N, 75° 46' 43" E]. The various parts like Peltier principle base TER, Ice box, fan, heat sink is used and observations have been taken for one hour. 2.1 Experimental Set-up: Thermoelectric cooling uses the Peltier effect to create a heat flux between the junctions of two different types of materials. A Peltier cooler / heater / thermoelectric heat pump is a solid-state active heat pump as shown in Figure 1, which transfers heat from one side of the device to the other, with consumption of electrical energy, depending on the direction of the current. Thermoelectric Peltier Modules are used in various applications where electricity is not reached at now, and it runs by solar panel: Water Machines, Medical Equipment, Cooling boxes and small fridges, Massagers, Electronic Parts cooling (Processors, Integrated circuits) and many more.
Fig. 1 Principle of Thermoelectric Refrigerator ISBN-978-81-932091-2-7
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The experimental set-up was built in the Laboratory of college; it consists with a Peltier module TEC1-12706, Battery, Cooling fan, heat sink and a cooling box. The construction detail of module is shown in Figure 2. and specifications are shown in Table 1.
Fig. 3: Nomenclature of Thermoelectric Cooler Module The Cooling box / freezing box is made by thermocol, and the box outer size 200 ď&#x201A;´ 200 ď&#x201A;´ 200 mm and inner size is 170 ď&#x201A;´ 170 ď&#x201A;´ 170mm. The Properties of thermocol are: Table 2: Properties of thermocol Fig. 2: Schematic diagram of Thermoelectric Cooler Module (TEC1-12706), Solder Construction: 138°C, Bismuth Tin (BiSn) Table 1: Specification of TER module Mode l No.
TEC1 1270 6
Th=30°C
Imax, Am p
Tmax , °C
6.0
â&#x2030;Ľ67
Measurements W, L, T in mm
Vma x, Volt
x,
15.0
51.4
S. No. 1
Types of Properties
Properties
Thermal conductivity at 10°C mean temperature
2 3 4 5 6
Compressive strength Cross breaking strength Tensile strength Application range Water absorption by % volume for 7 days in water Self-ignition point Melting point
0.028-0.031 Kcal-m/hr. m2 .°c 0.8-1.6 Kg/cm2 1.4-2.0 Kg/cm2 3-6 kg/cm2 -200 +80 °C 0.5%
Qma W 40
40
3.6
The following safety features have been used for using TEC module: Heating or cooling with the same module is possible simply by reversing polarity. Lettered side of modules are the â&#x20AC;&#x153;hot sideâ&#x20AC;?. Do not attempt to use TEC1 Peltier Modules without a fan or liquid cooled heat sink. Due to extreme â&#x2C6;&#x2020;đ?&#x2018;&#x2021; temperature differentials, module damage, fire, or operator injury can occur when sufficient thermal resistance is not present. The nomenclature of the module is clearly indicating system configuration as shown in Figure 3.
7 8
300 °C 100 - 200 °C
A complete assembly of TER is shown in Figure 4 with module, fan and heat sink. All the specifications of TER module is presented above, whereas the ADDA make cooling fan operating at 20A and 0.20A DC power. The 40 ď&#x201A;´ 40 mm aluminium heat sink is used to dissipate the hot side heat into atmosphere. The Complete assembly is fastened with the help of steel screws. A luminous make battery is used to supply the DC power to the TER unit, which shown in Figure 5. A charger is also used before the battery for continuously charging the battery, whereas AC power is supplied to the system through charger. The parts of the TER system are purchased from market by 49.66 USD. ISBN-978-81-932091-2-7
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(d)TER pannel assembly. (a)TEC1-12706 module
Figure 4.. TER Pannel assembly with module, fan, and heat sink
Fig. 4 Photo of Experimental Thermoelectric Refrigerator
(b)Cooling Fan
(c)Heat Sink with Fins
2.2 Mathematical Modelling: The proposed methodology for performance analysis by Riffat and Ma [1] is used to evaluate the COP of the thermoelectric cooler. The thermoelectric cooler is working on Peltier effect, where the thermoelectric cooling effect is given by, Q = αIT (1) Where, α is the average Seebeck coefficient of the thermoelectric material, I is current supplied to the couple, and Tc is the cold junction temperature in °C. The current flow is producing resistive or Joule heating in the thermoelectric material. The Joule heating is given by, Q =I R (2) Where, R is the resistivity of the couple. The heat is conducted for hot end to the cold end through the thermoelectric material during ISBN-978-81-932091-2-7
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Where k is the thermal conductivity of thermocouple, and h & c indicates the hot and cold ends. The above equation (3) indicates that Q increases with increases the temperature difference across the couple. For the energy balance equation, combining equation (1), (2) and (3) as given by Q = Q â&#x2C6;&#x2019; 0.5Q â&#x2C6;&#x2019; Q Q = ÎąIT â&#x2C6;&#x2019; 0.5I R â&#x2C6;&#x2019; kâ&#x2C6;&#x2020;T
(4a) (4b)
Above equation (4) is the standard equation for evaluating the cooling effect. The electrical energy consumed by the TER can be estimated by Q = I R + ÎąIâ&#x2C6;&#x2020;T (5) Where, I is the current. The Coefficient of Performance (COP) of the TER can be calculated by dividing the equation (4) and (5), and we get COP =
.
=
â&#x2C6;&#x2020; â&#x2C6;&#x2020;
(6)
By solving above equation for condition = 0, Current can be optimised and for optimum current optimum COP can be estimated. The final equations for Optimum current and optimum COP is given by,
observed for without load condition such as 2.3 °C and maximum temperature for 600 ml loading is found to be 10.5 °C. 35 30 Room Temperatu re
25 Temperature, °C
operation; this rate of conductive heat can be evaluated by Q = k (T â&#x2C6;&#x2019; T ) = kâ&#x2C6;&#x2020;T (3)
200 ml water load
20 15 10 5 0
0 2 3 4 5 6 7 8 9 11121314151617192021222324252728 Time, Minute
Fig. 5. Performance of TER on April 3, 2017 (Operating on conventional energy)
Where, đ?&#x2018;? =â&#x2C6;? /đ?&#x2018;&#x2DC;đ?&#x2018;&#x2026;, Z is the figure of merits and it depends on the properties of the material. It should be higher for maximum COP of TER.
The cooling rate is very high and capacity of the module is low. For increasing the cooling capacity, number of panel can be fitted in the cooling box / refrigerator. The COP of the TER system is very low and it observed by 0.26, 0.22, 0.18 and 0.17 for without cooling load and with 200, 400, 500 ml water cooling load, respectively. TER run by conventional electricity is not feasible at now but for small cooling like for electronic cooling it is acceptable and found suitable option. TER can be run on solar cell. The solar energy is available freely and in abundant quantity. The cost of the complete system is estimated by 49.66 USD (1 USD = 64.44 Rs as dated on June 2, 2017).
3.
4.
đ??ź
=
â&#x2C6;&#x2020; /
(7)
By outing the value of I in equation (6) and we get, đ?&#x2018;?đ?&#x2018;&#x153;đ?&#x2018;? = (
)
(8)
Results and Discussions The experimental work for TER was carried out for operating on conventional energy on April 3, 2017. The Figure 6 shows the variation of temperature with respect to time at different-different conditions such as without cooling load, with 200, 400, 600 ml water cooling load. Initial condition for all loading conditions is same as at 30.9 °C and the minimum temperature after 28 minute is
Conclusions Thermoelectric refrigerator is new and renewable technology for the scientific community; so many researchers are doing their work on improving the performance of TER. It can be possible only due to increasing the value of figure of merit of thermoelectric material. The performance analysis has been carried out with the experimental observations at Jaipur India. It is concluded that lowest ISBN-978-81-932091-2-7
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temperature for without cooling load to 600ml cooling load have been achieved by 2.3°C and 10.5°C for the interval of 28-minute time. The COP of the system is estimated by 0.22, 0.18 and 0.17 for without cooling load and with 200, 400, 500ml water cooling load respectively. The system cooling effect can be increased by cascading of the module and by putting the number of module at different places on the sides of the Refrigerator. It can be run by solar energy, means its application can be widely increases up to interior areas of the country, where no conventional electricity till now. Nomenclature: COP Coefficient of Performance Current (A) I thermal conductivity of k thermocouple (W m-K_1) electrical resistivity of the R thermocouple (VA_1) Cold side Temperature ( °C) T Hot side Temperature ( °C) T DT temperature difference between hot and cold end (8C) heat flow at cold side (W) Q heat conduction from the hot end to Q cold end (W) electrical energy consumption by Q the module, W heat flow at hot side (W) Q joule heat generation rate (W) Q Peltier heat pumping rate (W) Q Seebeck coefficient of α thermoelectric material (W/A-K) References: 1. Riffat S. B. and Ma X., “Thermoelectrics: a review of present and potential applications,” Applied Thermal Engineering, vol. 23, no. 8, pp. 913–935, 2003, DOI: 10.1002/er.991 2. Beitner S, Hand case, Patent No. US 4089184A, Publication date May 16, 1978.http://www.google.com/patents/US 4089184. 3. Beitner S, Thermoelectric cooler, patent no. US 4627242A, Publication date Dec 9, 1986,
http://www.google.com/patents/US46272 42. 4. Reed K L H, Hatcher, I Compact thermoelectric refrigerator, patent no. US 4326383A, publication date April 27, 1982, http://www.google.com/patents/ US4326383 5. Brian V. Park, Austin; Malcolm C. Smith, Jr., La Porte, both of Tex.; Ralph D. McGrath, Granville, Ohio; Michael D. Gilley, Rowlett, Tex.; Lance Criscuolo, Dallas, Tex.; John L. Nelson, Garland, Tex. Patent no. 5,522,216, Publication date June, 4, 1996. 6. Barako M T; Park W; Marconnet A M; Asheghi M; Goodson K E, Thermal Cycling, Mechanical Degradation, and the Effective Figure of Merit of a Thermoelectric Module. Journal of Electronic Materials; Warrendale 42 (3 ) (Mar 2013): 372-381. DOI: 10.1007/s11664-012-2366-1. 7. Guler N F, Ahiska R, Design and testing of a microprocessor-controlled portable thermoelectric medical cooling kit. Applied Thermal Engineering 22 (2002) 1271–1276, DOI: 10.1016/S13594311(02)00039-X. 8. Chen, K. and Gwilliam, S. B. (1996), An analysis of the heat transfer rate and efficiency of TE (thermoelectric) cooling systems. Int. J. Energy Res., 20: 399–417. doi:10.1002/(SICI)1099114X(199605)20:5. 9. Chein R, Huang G. Thermoelectric cooler application in electronic cooling. Applied Thermal Engineering 2004; 24(14– 15):2207–17. DOI: 10.1016/j.applthermaleng.2004.03.001 10. Dai Y. J., Wang R. Z., and Ni L., “Experimental investigation and analysis on a thermoelectric refrigerator driven by solar cells,” Solar Energy Materials & Solar Cells, vol. 77, no. 4, pp. 377–391, 2003. DOI:10.1016/S09270248(02)00357-4. 11. Astrain D., Vian J.G., and Albizua J. (2005), Computational model for refrigerators based on Peltier effect application. Applied Thermal ISBN-978-81-932091-2-7
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12.
13.
14.
15.
Engineering. 25, 3149-3162. DOI: 10.1016/j.applthermaleng.2005.04.003. Sabah A. Abdul-Wahab, Sabah A. AbdulWahab, Ali Elkamel, Ali M. Al-Damkhi, Is’haq A. Al-Habsi, Hilal S. Al-Rubai’ey, Abdulaziz K. Al-Battashi, Ali R. AlTamimi, Khamis H. Al-Mamari, Muhammad U. Chutani . Design and experimental investigation of portable solar thermoelectric Refrigerator. Renewable Energy 2009; 30; 30–34. DOI: 10.1016/j.renene.2008.04.026. Putra N., 2009, “Design, manufacturing and testing of a portable vaccine carrier box employing thermoelectric module and heat pipe”, Journal of Medical Engineering & Technology, 33 (3): 232237, DOI: 10.1080/03091900802454517. Adeyanju A.A., E. Ekwue and W. Compton, 2010, “Experimental and Theoretical Analysis of a Beverage Chiller”, Research Journal of Applied Science, 5 (3): 195-203, DOI: 10.3923/rjasci.2010.195.203. Gillott Mark, Liben Jiang and Saffa Riffat, 2010, “An investigation of thermoelectric cooling devices for small-scale space conditioning applications in buildings”, International Journal of Energy Research, 34, (9): 776–786, DOI: 10.1002/er.1591.
16. Zheng XF, Yan YY, Simpson K. A potential candidate for the sustainable and reliable domestic energy generationthermoelectric cogeneration system. Applied Thermal Engineering 2013; 53(2): 305–11, DOI: 10.1016/j.applthermaleng.2012.03.020. 17. Ranjana H., Kaushik S C, Manikandan S. Experimental Study and Analysis on Novel Thermo-Electric Cooler Driven by Solar Photovoltaic System. Applied Solar Energy, 2016, Vol. 52, No. 3, pp. 205– 210. DOI: 10.3103/S0003701X16030063. 18. Zhou Y, and Yu J., “Design optimization of thermoelectric cooling systems for applications in electronic devices,” International Journal of Refrigeration, vol. 35, no. 4, pp. 1139–1144, 2012. DOI: 10.1016/j.ijrefrig.2011.12.003. 19. Twaha S, Zhu J, Yan Y, Li B. A comprehensive review of thermoelectric technology: Materials, applications, modelling and performance improvement. Renewable and Sustainable Energy Reviews 65 (2016) 698–726, DOI: 10.1016/j.rser.2016.07.034.
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Transcritical CO2 Based Dedicated Mechanial Sub Cooling VCR System: A Review Neetu Kumari, Amit Sharma Department of Mechanical Engineering Deenbandhu Chhotu Ram University of Science and Technology Corresponding Author: kneetu50@gmail.com , amitsharma.me@dcrustm.org
ABSTRACT Use of synthetic refrigerants is restricted under several agreements because of their detrimental effect on our environment. Owing to the fact, that they have high global warming potential (GWP) and ozone depletion potential (ODP). So again, carbon dioxide is gaining popularity in the areas of refrigeration and air conditioning because of its eminent properties as a refrigerant. In this paper we are presenting the investigation of the performance of transcritical CO2 in the Indian conditions so that further scope of using carbon dioxide as a refrigerant increase in the future. India has a vast assortment of climates ranging from tremendously hot desert regions to high altitude sites with extremely cold conditions. And it is also proved by researchers that after some modifications transcritical CO 2 may provide better results as compared to the synthetic refrigerants. However, there is a very wide gap in using CO 2 in applications due to less research was done in this area, especially in Indian context. Keywords: - Natural Refrigerants, CO2, Transcritical, Dedicated Mechanical Subcooling . Looking at it, we are again turning towards INTRODUCTION: natural refrigerants and CO2 being a natural Carbon dioxide (CO2) was the first refrigerant refrigerant is a best supplement because of its ever used in refrigeration systems and till the excellent properties as a refrigerant. It can be 1930; almost 80% of marine applications were extracted from environment economically as using CO2 as a refrigerant. With introduction of well as it is safe (zero ODP and low GWP), CFCs (nontoxic, nonflammable and operated nontoxic, non-flammable and environmentefficiently over a range of temperatures) [1] in friendly, high volumetric capacity lower 1950, there is a sharp decline in uses of CO2, compressor ratio and exonerated thermo because of its high operating pressure. From physical properties [2]. It is an inert gas, perfect 1950 onwards, CO2 has been completely for every normal material experienced in a replaced by CFCs. CFCs were restricted under refrigerating circuit, both metals and plastics. Montreal protocol because of their high ozone And its credit goes to professor Gustove, who depletion potential (ODP). Consequently, CFCs was the first to draw the attention towards the replaced by HCFCs which have an ozone use of CO2 and he also eliminates the problem depletion potential to a less extent. But HCFCs that was occurred with the transcritical CO2 also banned during under Montreal Protocol, subcritical system operating with heat rejection which results introduction HFCs, which do not temperature in the vicinity of critical point in his have ODP but having high global warming patent [3] application for a CO2 transcritical potential(GWP). Therefore, they are restricted cycle for automotive air conditioning system. under the Kyoto Protocol. In 2015, European CO2 has low critical temperature (30.98°C), Union (EU) made a new regulation by which all which causes it to operate in transcritical the Fluorinated greenhouse gases will be phased conditions. However, in transcritical out by 2030 with GWP greater than 150 from refrigeration system heat rejection takes place mobile air conditioning systems. above the critical point of CO2. That’s why in the ISBN-978-81-932091-2-7
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transcritical carbon dioxide cycle we make use of gas cooler instead of condenser. Because at high temperatures carbon dioxide becomes dense and it is not possible to reject heat in the condenser, so we use gas cooler instead of condenser. And it operates at very high pressure that’s major problem with this cycle. Many efforts have been done to enhance the transcritical carbon dioxide cycle so that it can give equal or more efficiency than synthetic refrigerants give. Transcritical CO2 cycle gives appreciable performance in the cold regions. But the performance of gas cooler is highly sensitive to operating temperature and pressure for tropical or Indian climatic conditions (where the ambient temperature is higher) [4], so modification is necessary to improve the coefficient of performance (COP) of the transcritical cycle. And various techniques were applied by many researchers to modify the performance of transcritical CO2 refrigeration cycle. An experiment was performed using internal heat exchanger in a transcritical CO2 refrigerator to improve the efficiency of the single stage system [5]. Sarkar et al [6] and Bell et al [7] shows that COP of transcritical cycle for warm climates can be enhanced by employing parallel compression. Sarkar [6] employed a parallel compression economization, is a process of improving the performance of transcritical CO2 refrigeration cycle. in which refrigerant vapor is compressed up to supercritical discharge pressure in two different non-mixing streams. As shown in fig.1 ,one stream coming from economizer (at point 8) , another stream from evaporator (at point 2) and goes to gas cooler. COP of transcritical CO2 cycle will be optimum at combination of specific operating parameters purposed by Kim et al. [2]. Winkler et al. [8] proposed that by incorporating thermoelectric subcooler as a dedicated subcooler at the exit of a gas cooler of a transcritical CO2, which increases the COP by 16% and cooling capacity by 20%, even after external power consumption taken into account. Sarkar [9] showed the increase in COP, volumetric cooling capacity and decrease in high side pressure, compressor pressure ratio and
compressor discharge temperature with the use of thermoelectric subcooler in the transcritical CO2 refrigeration system. Aklilu Tesfamichael et al.[10] studied transcritical CO2 refrigeration cycle by making a model and simulated at different operating parameters. And found that the cycle pressure (corresponds to maximum COP) is depends on gas cooler exit temperature and evaporator temperature and cycle was more suitable for air conditioning than refrigeration. Dubey et al. [11] studied the transcritical CO2/propylene (R744–R1270) cascade system for cooling and heating applications and found that transcritical CO2-propylene is better than N2O-CO2, CO2-propane and subcritical cascade cycles in terms of COP. The maximum COP increases with the increase in evaporator exit temperature, but decreases as gas cooler exit temperature. Rawat et al. [12] demonstrated that COP of transcritical carbon dioxide system increases with a decrease in gas cooler inlet temperature of external fluid and increase in evaporator temperature and not affected by the effectiveness of internal heat exchanger. Exergy Study : Yang et al. [13] found that transcritical CO2 cycle with expander has 33% more COP and 30% more exergy efficiency than the throttling valve cycle. And largest exergy loss occurs at throttle valve (38%) in case of throttling valve cycle and in expander it occurs from gas cooler (38%) and compressor (35%). Exergy analysis of transcritical CO2 cycle is performed with throttling valve and ejector by Ma Yi-Tai et al. [14] and It is found that ejector reduces 70% more exergy loses and increases COP up to 36% in comparison to throttling valve. Goodarzi et al. [15] Studied the modified transcritical CO2 refrigeration cycle. Modification was made by extracting a line of saturated vapor flow from separator and feeding to the intercooler and concluded that COP of the modified cycle was improved by 26.89% as comparison to original cycle operating at a particular set of parameters. And it is also repoted that as compare to original cycle this modification averagely decreased the exergy destruction rate by 18.6%. ISBN-978-81-932091-2-7
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Study of transcritical CO2 cycle with dedicated mechanical subcooling:J.W.Thornton et al. [16] compared an optimum value of subcooling evaporator temperature of an ideal dedicated mechanical subcooling cycle and of a property dependent computer model. Results exhibit that the optimum temperature of subcooler evaporator greatly depends on the extreme temperatures of the cycle, but less rely on the subcooler heat exchanger parameters. Rodrigo llopis et al [17] evaluate a transcritical CO2 refrigeration system with dedicated mechanical subcooling at two evaporating temperatures (0 & 10°C) and three heat rejection temperatures (24, 30 &40°C). And obtain a increment of 55.7% in cooling capacity and 30.3% in COP for proposed system. Residential building of 1.5 ton was taken and experiment was conducted with and without using dedicated subcooler at room temperature of 18 to 22°C by Qureshi et al. [18] . Increase in efficiency was found by 21% with the use of dedicated subcooler. Fig. 2 explains the working of dedicated mechanical subcooling cycle. Subcooling is done in the vapor compression refrigeration cycle to improve the coefficient of performance of the system. Subcooling of the refrigerant is done at the exit of condenser, to allow the refrigerant to enter into the main refrigeration cycle with lower quality so that it can absorb more heat from the refrigerated space in the evaporator. In dedicated mechanical Subcooling vapor compression refrigeration system, a small vapor compression refrigeration cycle is employed to perform Subcooling. As shown in figure 2, there are two cycles one is main refrigeration cycle (situated below) and other is dedicated subcooling cycle. Both the cycles are coupled at the exit of condenser with the help of subcooler. “In practice, the components of the subcooling cycle are a fraction of the size of the main cycle components and perform through much smaller temperature extremes. For this reason, the COP of the subcooling cycle is appreciably higher than that of the main refrigeration cycle. This high subcooling cycle COP can result in an increase in the overall cycle COP” [16].
Fig. 3, clearly shows that dedicated mechanical subcooling cycle allows the refrigerant to enter into the evaporator of main cycle with a lower quality. Consequently, an increase in refrigeration capacity per unit mass of refrigerant circulated occurs. Study of CO2 based transcritical cycle in Indian context: Nilesh Purohit et al. [19] demonstrate that, parallel compression is more effective with transcritical CO2 cycle than inter-cooling in high ambient temperatures like India. Maximum improvement noticed in COP was about 25% for parallel compression configuration. And for parallel compression configuration the operating gas cooler pressure was found lower. Figure 4 shows the basic transcritical carbon dioxide refrigeration cycle and its P-h diagram as given by Nilesh purohit et al. [19]. Refrigerant flows from compressor to gas cooler where it gives off its heat to another fluid and then through the expansion device goes into the evaporator and takes heat from the refrigerated space. As shown in P-h diagram, at the exit of compressor it is above critical point and heat rejection takes place above critical point in the gas where no saturation point exists. So at gas cooler exit the gas cooler pressure is independent of the refrigerant temperature. And evaporation takes place below critical point. Dasgupta et al. [20] reported that performance of transcritical CO2booster system for supermarket with expander is higher as compared to that without expander, the mass flow rate and gas cooler operating pressure is lower for cycle with expander, gas cooler inlet temperature is higher for cycle with expander beyond the operating limit (12 MPa) in warm climates. Nilesh et al. [21] analysed five CO2 booster refrigeration cycles on the basis of energy and economic aspects by taking temperatures from the four cities of world (warm climates). New Delhi found to be having higher annual energy savings, the recovery time is longer and the total money savings are lower owing to lower electricity tariff. Gupta [22] demonstrate that COP of a transcritical cycle can be improved by ISBN-978-81-932091-2-7
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employing a recovery turbine. This study was done for design and operating parameters based on local environmental conditions for the best possible performance (in Indian context).
Conclusion: CO2 having GWP (=1) is a very promising incumbent for refrigeration and air conditioning industry. CO2 based systems have been giving promising results in cold climates and now researchers taking this CO2 based system and studying it theoretically and experimentally for the various refrigeration applications. In Indian context, also it is being studied for the supermarkets based on energetic performance and more exergetic performance study should be performed. Figure contents: Fig: l : layout and p-h diagram of CO2 cycle with parallel compression economization[6] Fig 2. : Schematic of a vapor compression cycle with dedicated mechanical sub-cooling[18] Fig 3. : Pressure-enthalpy diagram of a refrigeration cycle with dedicated subcooling [18]. Fig.4 : Basic transcritical CO2 refrigeration cycle [19]
References: [01] Brian T. Austin, K. Sumathy, 2011. Transcritical Carbon Dioxide Heat Pump Systems: A Review. Renewable and Sustainable Energy Reviews 15; 4013– 4029. [02] M.-H. Kim, J. Pettersen, And C. W. Bullard, 2004. Fundamental Process and System Design Issues in CO2 Vapor Compression Systems. Progress in Energy and Combustion Science, Vol. 30, Pp. 119-174. [03] Lorentzen, G., 1990. Trans-Critical Vapour Compression Cycle Device. Patent WO/07683. [04] D. K. Gupta And M. Dasgupta, 2010. Gas Cooler Design Issues for Trans-Critical Carbon Dioxide Refrigeration System in Indian Context. In: Proceedings of the 3rd International Conference on Advances in Mechanical Engineering, SVNT, Surat, India, Pp. 229-233.
[05] Aprea, C., Maiorino, A., 2008. An experimental evaluation of the transcritical CO2 refrigerator performances using an internal heat exchanger. International Journal of Refrigeration 31, 1006–1011. [06] J. Sarkar, N. Agrawal, 2010. Performance Optimization Of Transcritical CO2 Cycle with Parallel
Compression Economization. International Journal of Thermal Sciences, Vol. 49, Pp. 838-843.
[07] I. Bell, 2004. Performance Increase of Carbon Dioxide Refrigeration Cycle with the Addition of Parallel Compression Economization. In: Proceedings of 6th IIR Gustav Lorenzen Natural Working Fluids. [08] Winkler, J., V. Aute, B. Yang, And R. Radermacher, 2006. Potential Benefits of Thermoelectric Elements used with AirCooled Heat Exchangers. In: Proceedings of the International Refrigeration and Air Conditioning Conference At Purdue, Purdue University, West Lafayette, IN, July 17–20, Paper R091. [09] Jahar Sarkar, 2011. Performance Optimization of Transcritical CO2 Refrigeration Cycle with Thermoelectric Subcooler. International Journal of Energy Research. [10] Aklilu Tesfamichael Baheta, Suhaimi Hassan, Allya Radzihan B Reduan, and Abraham D. Woldeyohannes, 2015. Performance Investigation of Transcritical Carbon Dioxide Refrigeration Cycle. 12th Global Conference on Sustainable Manufacturing. Procedia CIRP 26, 482 – 485. [11] Alok Manas Dubey, Suresh Kumar, Ghanshyam Das Agrawal, 2014. Thermodynamic Analysis of a Transcritical CO2/Propylene (R744–R1270) Cascade System for Cooling and Heating Applications. Energy Conversion and Management 86; 774–783. [12] K.S. Rawat, V.S. Bisht, A.K. Pratihar, 2015. Thermodynamic Analysis and Optimization of CO2 Based Transcritical Cycle. International Journal for Research in ISBN-978-81-932091-2-7
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Applied Science and Engineering Technology, Volume 3 Issue III. [13] Jun Lan Yang, Yi Tai Ma, Min Xia Li, Hai Qing Guan, 2005. Exergy Analysis of Transcritical Carbon Dioxide Refrigeration Cycle with an Expander, Energy 30, 1162– 1175. [14] Ma Yi-Tai, Wei Yun Xia, Li De-Ying, Sun Fang-Tian, 2011. Exergy Analysis of Transcritical Carbon Dioxide Refrigeration Cycle with an Ejector. International Conference on Computer Distributed Control and Intelligent Environmental Monitoring. [15] Goodarzi M, Gheibi A., 2015. Performance Analysis of a Modified Trans-Critical CO2 Refrigeration Cycle. Applied Thermal Engineering; 75:1118–25. [16] J.W.Thornton, S. A. Klein, J. W. Mitchell, 1992. Dedicated Mechanical Subcooling Design Strategies for Supermarket Applications. International Refrigeration and Air Conditioning Conference. [17] Rodrigo Llopis , Laura Nebot-Andrés, Ramón Cabello, 2016. Experimental Evaluation of a CO2 Transcritical Refrigeration Plant with Dedicated Mechanical Subcooling. International Journal of Refrigeration 69,361–368.
Fig: l : layout and p-h diagram of CO2 cycle with parallel compression economization[6]
[18] Bilal A. Qureshi, Muhammad Inam, Mohamed A. Antar, Syed M. Zubair, 2013. Experimental Energetic Analysis of a Vapor Compression Refrigeration System with Dedicated Mechanical Sub-Cooling. Applied Energy 102, 1035–1041. [19] Nilesh Purohit, Dileep Kumar Gupta, M.S. Dasgupta, 2015. Thermodynamic Analysis of Trans-Critical CO2 Refrigeration Cycle in Indian Context. International Journal of Scientific and Technical Advancements. [20] Mani Sankar Dasgupta, Nilesh Purohit, Dileep Kumar Gupta, 2016. Thermodynamic Analysis of CO2 TransCritical Booster System for Supermarket Refrigeration in Warm Climatic Conditions. 4th IIR Conference on Sustainability. [21] Nilesh Purohit, Dileep Kumar Gupta, Mani Sankar Dasgupta, 2017. Energetic and Economic Analysis of Trans-Critical CO2 Booster System for Refrigeration in Warm Climatic Condition. International Journal of Refrigeration; Volume 80, Pages 182-196. [22] Dileep Kumar Gupta, 2017. Performance of CO2 Transcritical Refrigeration System with Work Recovery Turbine in Indian Context. Energy Procedia 109, 102 – 112.
Fig 2. : Schematic of a vapor compression cycle with dedicated mechanical sub-cooling[18] ISBN-978-81-932091-2-7
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Fig 3. : Pressure-enthalpy diagram of a refrigeration cycle with dedicated subcooling [18].
Fig.4 : Basic transcritical CO2 refrigeration cycle [19]
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Pump as Turbine: Review of Simple Modifications for Performance Improvement Doshi A. V.*; Bade M. H, Mechanical Engineering Department, Sardar Vallabhbhai National Institute of Technology, Ichchhanath, Surat-395007, Gujarat, India Corresponding Author: avdoshi2001@gmail.com
Abstract Energy to everybody is necessary for holistic development of society. Renewable energy sources are gaining importance and their share in total energy is increasing as compared to fossil fuels in India. For standalone energy generation, among various renewable energy conversion systems, pump as turbine (PAT) are one of the potential device for micro hydro and energy recovery applications. Being PATs are not designed for turbine operations, there is a scope for optimization of their performance after selection for a field application. In this paper, literature related to performance enhancement techniques is reviewed. However, main focus of this paper is to highlight the simple and cost-effective modifications in PAT, which justifies the basic philosophy of low cost solution for micro hydro applications. Keywords: Pump as turbine, reverse mode operation of pump, simple modifications in PAT, performance enhancement of PAT
1.
Introduction The development of nation as whole is considered in two major areas one is economic and other is social. For both, energy is playing a pivotal role. One of the important challenges for government is to provide reliable, secure, and affordable energy to everybody. There are several energy sources mainly categorized as non-renewable and renewable energy sources. Due to climate change and limited resources of non-renewable energy sources, renewable energy sources are gaining importance and their contribution in total energy generation is increasing. Among various renewable energy sources, micro-hydro power can be one of the most important alternatives to isolated rural communities due to the advantages of electrification and the associated progress, as well as to improve the quality of life. However, due to higher cost of conventional turbines, pump operation in reverse mode as turbine is proved more cost effective. This is due to mass manufacturing of pumps in different sizes and designs, which can be matched with that of available conditions of natural streams. Pump as turbine (PAT) is one of the feasible solutions to the energy problems in rural and hilly areas. PAT is a pump operating in turbine mode by changing the direction of flow and hence direction of rotation of an impeller. PAT
is also finding its application in the area of energy recovery systems for the existing process industries. Use of PATs in large hydropower plant as pump storage plant is very well known and established method. All of these applications of PAT are still attractive as pumps are relatively simple machines with no special design and are readily available in most of the developing countries. In addition, their installation commissioning and maintenance are easy and cheap and from the economical point of view, their payback period for small hydropower application is approximately two years. Even though use of PAT as micro hydro or Pico hydro application seems to be very attractive due to all points which are discussed above, it has always demanded for detail investigations and careful research before they are used for such purposes. The most important and difficult area of PAT research is about their selection to run them in turbine mode as per the site requirements. As pumps are design for the development of pressure head, so for in energy recovery where they are used in turbine mode operations, their performance may not be optimal, hence researchers are also finding another area of PAT research, which is to modify the geometry of the selected PAT to ISBN-978-81-932091-2-7
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improve the performance. Also, from the field application point of view, further area of research which are evolving now a days is to get solution to the poor part load performance, overcoming the problem of runaway condition, overall system design and finding out the use of PAT as energy recovery unit. In general, out of various areas of PAT research, simple modifications in PAT for performance improvement is one of the important area, where researchers have shown keen interest, as it keeps cost benefits of PAT intact. In this paper, review of simple modifications and future scope of research is discussed. Additionally, potential modifications are highlighted. Furthermore, radical modifications are summarized at the end. 2 Modification to improve PAT performance To enhance the PAT performance, various modifications performed are mainly categorized in two parts: simple and radical modifications. The modifications carried out on PATs by various researchers are summarized Figure 1. Several researchers have worked in the area of understating the internal hydraulics of PATs by proposing the theoretical model, which is useful to analyze performance improvement by simple modifications. 2.1 Research on theoretical model for simple modifications in PAT Singh (2005) has made extensive work in this area. In his work, a flow zone approach is followed, in which PAT control volume is divided into total seven flow zones with detailed analysis of energy transfer and losses in each of the zones. In the work, to evaluate the PAT performance external and internal parameters are identified. External parameters are classified as input parameters like total head (H), Discharge (Q) and output parameters like hydraulic shaft power (Phyd.shaft) and rotational speed (N). Internal parameters are like whirl velocity (Vu) and flow velocity (vm) of the fluid at the impeller inlet and outlet. Also, to see any variation in the external parameters an interlink between two dependent hydraulic variable total head (H) and hydraulic shaft power (Phyd.shaft) for PAT control volume is established in terms of hydraulic losses and net rotational momentum (Eulerâ&#x20AC;&#x2122;s head which is a function of internal
parameters). Further analytical model proposed by Singh (Singh 2005) is appropriately modified to account the influence of non-flow zone (a region available in the side room of PAT control volume) and transition zone on PAT performance by Doshi et al. (2017). 2.2 Simple Modifications in PAT 2.2.1 Inlet impeller rounding Lueneburg and Nellson (1992) had performed the modification on PAT of inlet blade rounding, and rise in the efficiency of PAT stated between 1 and 2.5 %. Singh (Singh 2005) based on flow zone approach and internal hydraulics study, identified the area at the inlet blade and shrouds of an impeller as critical and feasible area for implementing the modification in PATs. So, rounding operation is performed at the inlet of the blades and shrouds (see Figure 2) of an impeller to reduce the flow separation and shock loss component. In his study work, total 8 PATs of different specific speeds (between 24.5 rpm and 94.4 rpm) were selected, for all the PATs, performance improvement is analyzed at three operating conditions viz. (i) part load (ii) BEP and (iii) the overload. It is noted that overall rise in the efficiency of PAT due to this modification is in the range of 1.5 % to 2.5 %. Suarda et al. (2006) has performed the experiment on 18 rpm PAT by rounding of the inlet ends of the impeller tips like a bullet-nose shape to preclude excessive turbulence for efficiency consideration, which is shown in the Figure 3. The pump as turbine was operated at the maximum head of 13 meter, and observes change in the power and efficiency of the pump as turbine after modification is slightly higher than before the modification at BEP point. Derakhshan et al. (2009) has modified the optimized impeller of specific speed (Nq = 18.33 rpm) by rounding of leading edges and hub/shroud inlet edges of PAT. Rounding of an impeller has shown improvement in the values of discharge, head, power and efficiency to 7.7 %, 9.5 %, 18.6 % and 2.5% respectively. Doshi et al. (Doshi et al. 2017) had analyzed impeller inlet blade rounding individually, i.e. in three stages as impeller blade tip rounding, inner shroud rounding (see Figure 4) and outer shroud rounding with four selected PATs of specific speed between 19 rpm to 54 rpm covering low to medium range. From work, it ISBN-978-81-932091-2-7
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is found that contribution in the performance improvement of PAT from inlet blade rounding is comparatively higher than shroud rounding. Comparing similar modification carried out by the various researchers, further, it is noted that the rise in the efficiency due to rounding of impeller at the inlet is maximum up to 2.5 %. For further enhancement, it is suggested to go for redesigning of blade profile. 2.2.2 Insertion of inlet casing ring Singh (Singh 2005) has discussed about various turbulent and shock losses available in the region between casing mouth and impeller periphery of PAT. These losses are mainly due to clearance (between casing mouth and tip of the blade) and sharp edges of the fixed blades at the inlet. In order to reduce such losses, an external stationary ring is fixed at the casing mouth to reduce the clearance between the casing mouth and impeller periphery. Two pumps (specific speeds 39.7 rpm and 79.1 rpm respectively) were selected for performance analysis by this modification; one (79.1 rpm) for flat ring and other (39.7 rpm) for the tapered ring insertion. The PAT with flat ring has shown the positive change in efficiency of maximum up to 1.4 %. 2.2.3 Suction eye enlargement In most of centrifugal pumps, suction eye area is contracting from the exit of impeller plane towards the casing eye flange. However, in PAT mode operation this area should be of diffuser type with enlarging from exit of impeller plane to the casing eye. This would help in deceleration of the flow resulting in pressure recovery, hence overall improvement in the performance of PAT. Singh (Singh 2005) has taken two pumps (specific speeds 24.5rpm and 35.3 rpm respectively) for testing performance enhancement of this modification. Mixed results were obtained showing no improvement in efficiency for 24.5 rpm PAT and the reduction in efficiency for 35.3 rpm PAT at BEP. However, both the PATs have shown rise in the efficiency at part load condition. 2.2.4 Casing eye rib removal In many pumps, manufacturers add the rib in the casing eye region to break the pre-swirl at the pump entry. In turbine mode operation this rib will run axially along the casing eye length
and helps in reducing the swirl flow component at the exit of PAT, on the other side they will add to the friction losses due to obstructions. Singh (Singh 2005) has shown interesting results about the influence of casing eye rib on the performance of PAT. For this work, four pumps of different specific speeds (36.4 rpm, 39.7rpm, 46.4 rpm and 79.1 rpm) were selected. Out of these four test PATs only one PAT having specific speed of 39.7 rpm has given a positive performance with rise in efficiency of about 1 % at BEP and up to 1.6 % in part load region. 2.3 Radical modifications in PAT Few researchers also tried for performance improvement of PATs by changing the overall geometry of PAT, though it may leverage cost benefit of simple modifications. Further, researchers have tried to improve the performance of PAT by adopting impeller with splitter blades (Yang et al. 2012). Giosio et al. (2015) had tried to improve the performance of PAT at part load conditions by regulating the flow rate with insertion of guide vanes, which are generally used in conventional turbines. Recently impeller with special type are design for PAT operation and performance improvement in PAT is analysed theoretically, experimentally and numerically (Wang, Kong, et al. 2017, Wang, Wang, et al. 2017). 4 Conclusions: There are simple as well as radical modification experimented by various researchers for performance improvement of PAT. In simple modifications, inlet blade rounding is found as the most reliable and effective modification giving performance enhancement up to 2.5 %. Therefore, it is strongly suggested. To get performance improvement above 2.5 %, one may try for radical changes in PAT. In this, one of the modifications suggested is changing design of impeller to match the flow condition to reduce hydraulic losses. References: 1. Derakhshan, S., Mohammadi, B., and Nourbakhsh, A., 2009. Efficiency Improvement of Centrifugal Reverse Pumps. ASME Journal of Fluids Engineering, 131 (2), 21103. ISBN-978-81-932091-2-7
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Doshi, A., Channiwala, S., and Singh, P., 2017. Inlet impeller rounding in pumps as turbines: An experimental study to investigate the relative effects of blade and shroud rounding. Experimental Thermal and Fluid Science, 82, 333–348. Giosio, D.R., Henderson, A.D., Walker, J.M., Brandner, P.A., Sargison, J.E., and Gautam, P., 2015. Design and performance evaluation of a pump-asturbine micro-hydro test facility with incorporated inlet flow control. Renewable Energy, 78, 1–6. R.Lueneburg and R.M.Nellson, 1992. Hydraulic power revcovery turbines, in: V.S.Lobanoff et al. (eds.), Centrifugal Pumps- Design and Application. Second ed. Boston, US: Second Edition, Gulf Professional Publishing. Singh, P., 2005. Optimization of Internal Hydraulics and of System Design for PUMPS AS TURBINES with Field Implementation and Evaluation. Ph.D thesis University of Karlsruhe,Germany. Suarda, M., Suarnadwipa, N., and Adnyana, W.B., 2006. Experimental Work on Modification of Impeller Tips of a Centrifugal Pump as a Turbine. The 2nd Joint International Conference on ‘Sustainable Energy and Environment (SEE 2006)’, 8 (November), 21–25. Wang, T., Kong, F., Xia, B., Bai, Y., and Wang, C., 2017. The method for determining blade inlet angle of special impeller using in turbine mode of centrifugal pump as turbine. Renewable Energy, 109, 518–528. Wang, T., Wang, C., Kong, F., Gou, Q., and Yang, S., 2017. Theoretical, experimental, and numerical study of special impeller used in turbine mode of centrifugal pump as turbine. Energy, 130, 473–485. Yang, S.S., Kong, F.-Y., Fu, J.-H., and Xue, L., 2012. Numerical Research on Effects of Splitter Blades to the Influence of Pump as Turbine. International Journal of Rotating Machinery, 2012, 1– 9.
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PAT MODIFICATIONS
SIMPLE
RADICAL
INSERTION OF GUIDE VANES
ROUNDING OF IMPELLER AT INLET
REMOVAL OF CASING EYE RIB
IMPELLER WITH SPLITTER BLADES
SUCTION EYE ENLARGEMENT • INSERTION CASING RING
IMPELLER WITH NEW DESIGN
OF
Figure 1: Summary of modifications in PATs Blade with rounding
Blade without rounding
(a) section of the impeller front view Shroud without rounding
Back shroud
Shroud with rounding
Front shroud
(b) section of the impeller side view Figure 2: Impeller Blade Rounding at inlet (Singh 2005)
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Figure 3: Inlet impeller rounding (Suarda et al. 2006)
Flow zone Transition flow zone
Flow zone
Non-flow zone
Non-modified inner shrouds
Sharp eddies
Decreased wakes and changed meridional velocity profile
Inner shroud rounding
Figure 4: Hydraulic Effects due to Inner Shroud Rounding (Doshi et al. 2017)
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GROWTH, DESIGN ASPECTS AND APPLICATIONS OF PHOTOVOLTAIC SYSTEMS Jayesh Nehiwal 1Vineet Gehlot2, 1 Jodhpur Institute of Engineering &Technology 2MBM Engineering College, Jodhpur Corresponding Author: jayeshnehiwal@gmail.com , vineet.gehlot@jietjodhpur.ac.in
ABSTRACT Solar energy is resource which cannot be used or exhausted completely. The temperature is 15 million 0 C at the center of Sun core and at its surface it is approximately reaching 6000 0C. Being an effective black body it has temperature of 57770C and so the sun effectively acts as a continuous fusion reactor, many such fusion reactions takes place and hence there is production of solar energy, one of the important reaction of hydrogen with four protons which combines to give helium nucleus. The reaction is here, 4(1H1) 2He4 + 26.7 Me V This highly exothermic reaction gives us energy in order of MeV which is collected and converted in the form of heat and further in electricity. This is really an important source of renewable energy and the technologies characterizing is as either passively solar or actively solar. The use of photovoltaic systems is in active solar power systems. In Passive solar system the techniques used are, that they orientate a building towards the Sun in such a way that maximum sunlight falls on PV systems, selection of material with favourable thermal, mass or light-dispersing applicative properties, and designing spaces so that can naturally circulate air. This paper is made to focus on photovoltaic solar cells, their designing aspects and their applications. This ability of producing electricity directly with the help of the sunlight in the most abundant natural resources, is the heart of this Photovoltaic research, and is explained as becoming one of the major sources of power for our better “greener” future. Keywords: Worldwide Scenario of Solar Energy, growth of solar PV system, designing of solar PV system and applications of solar PV system.
INTRODUCTION Contribution of Sun’s energy: It merely contributes 94% of energy to Planet, it also warms the surface of our earth and so the atmosphere so that huge forms of life can live. Without the solar energy, our earth will become completely as a rock moving in infinity space with temperature situations extremely low. We humans, consume lot of energy in our day to day life that within couple of years all of our existing fossil fuels which are coal, gas, petroleum, etc will get exhausted. Hence, solar energy has a major responsibility to ensure itself as best sustainable energy for our future generations and also it can minimize the problems of carbon emissions, global warming etc.
Photovoltaic collectors: These photovoltaic collectors are the collectors which convert solar radiation coming from sun directly into electricity, without any kind of use of heat engine in its configurations and with increase in demand and requirement of public integration and their purposes of using energy, the small scale utilization of solar energy for desalination, destination and detoxification of purposes with water has also increased. With the help of these solar collectors which are settled on the rooftops of buildings and with the help of photovoltaic cells of solar panels, the system is made to synchronized with the active as well passive energy systems. ISBN-978-81-932091-2-7
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Photovoltaic effect: A basic theory of solar cell is that, a wide area of semiconductor diode which is having PN junction due to fabrication of pentavalent element (Ph) or trivalent element(B) with tetravalent element (Si, commonly used for solar cells) to provide us charge carriers, either minority or majority depending upon holes or electrons concentration. When light or sun radiation is made to fall on this grouped semiconductor being PN in nature, this generates the electron hole pair giving a force or a kind of tension between the contacts of provided n- side and pside of semiconductor and when we apply the load, the current flows within this, making it as completion of circuit as flow of charge is flow of electric current and electric power is dissipated in it.
Fig.1: Complete solar PV system (source: www.solardirect.com)
GROWTH Humans are capable enough to capture the solar energy from sun directly, and with the help of passive and active solar energy systems intuitively in body. Ancient people in earlier times made their minds so as used to build their shelters and houses of stone or with clay so that the heat absorbed in it can easily be used in night time. Nowadays what builders use to do is somewhat similar to methods for
passively capturing the Solar Energy, with the help of photovoltaic cells. For example, the construction of houses done by them is planned with large double or triple paned types of windows so that can get a direction to capture the efficient sunlight and can magnify the warmness of sun. Active solar energy systems work on somehow the same principles as the passive systems used to do. But the Active solar systems also using the fluid like water to absorb heat or to store heat. Solar collectors which are oriented at the rooftops pumps the heat to the whole system of pipes and then further to the whole building, it is passed on. The best part of solar energy is, it is renewable energy resource and present in abundant amount in free in nature and the bad part of this is, that the cost of system for the use of consumer is expensive enough at initial stage of while installations. The technology of solar PV was known to us from the last decades and its utilization was a task to finish, its minimal cost of bills and efficiency in various other fields of industries can develop the whole system of integration in regards to this PV system. In India, the geographical location is favorable as Tropic of Cancer passes from middle of India hence for solar energy implementation in India can be done in worth, various companies are taking interest to develop their scope and earn in this field. Considering the socio-economic scenario, India's present situation is fair with it, but many other initiatives are planned and in a queue for their implementations. And on considering the historical scenario, the first commercial use of new solar cells was done in a spacecraft in the beginning of 1958. So from Small beginning to a Terrestrial, solar cell industry is putting their roots to grow rapidly to fight over Non Renewable sources in the coming years. These companies will increase the International resolves, reduce the CO2 emissions and produce effective energy for commercial purposes as well as industrial purposes. Some statistical figure shows the growth done in solar PV ISBN-978-81-932091-2-7
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systems in last decade over the coal and wind power plants in India. The report made by Central Electricity Authority (CEA) of India for the cost effectiveness for various Gol policy instruments for 1MW solar PV installed in 201617 in rural and urban areas of India have successful saving in energy and reduced the average electrical cost for nation. Table.1: Financial cost effectiveness for various Gol policy instruments for 1MWsolar PV installed in 2016-17(source: nitiaayog.com; CEA report on 175 GW RE by 2022)
PV Module: It is having PV cells which are wired in parallel so that it can increase the current and in series so that to achieve a higher voltage. Its basic function is to convert sunlight into DC electricity. The module is layered with protective covering of glass material. PV Inverters: The batteries used in PV systems can store direct current power which is used for many applications. These inverter are for the purpose to convert the low voltage DC into a higher voltage AC and hence can be used for other various applications. PV Controllers: Controller word defines its property that the battery life of PV system is in regards with these controllers. If battery is charged beyond its limitations then it will not function and if such happens then the battery life reduces. PV controller system basically helpful in opening the circuit between the PV battery and PV array when voltage rises beyond set . PV Batteries: Batteries are for purpose of storing charge and excess energy which is created by PV system and to use in night when there is no sunlight input is applied. These kinds of batteries have ability to discharge and are able to yield more current when applied to load appliances. Load: These are the electrical appliances which will consume the electricity produced or stored and are connected to the solar PV system such as tube lights, refrigerator, fan etc.
Sizing a solar PV system: 1. Determination of power consumption By the addition of each watt hour required for all the appliances and get the total watt hours required per day for all of the appliances(load).
DESIGNING A SOLAR PV SYSTEM The major components of solar PV system are:
Multiply it by the total watt hours per day by a factor of 1.3(for the total energy loss in our system, it is assumption) to get the total watt ISBN-978-81-932091-2-7
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hours per day which we will give to the PV panels of our PV system.
35 % bigger than the total watt requirement of the load. 4. Determination of sizing of battery The type of battery which is recommended for the solar PV system is ‘deep cycle battery’. In this type of battery, it gets discharge slowly and get charged comparatively faster. The battery is taken large enough so that it can store the enough amount of power to operate even in cloudy days. Calculation done for the total watt per day is taken and then divided by the factor of 0.85 (for the loss of battery), 0.6 (for the depth of discharge made by battery) and by the nominal battery voltage which is 12 volts in our case. Multiplying the above factor by the number of days of autonomy which is usually from 2 to 3, we consider 3 in our case.
Fig.2: Major components of PV system (source: www.solardirect.com) 2. Determination of sizing of PV panel PV modules of different size will produce different amount of power. And to find the actual size of PV module, the total peak watt (Wp) is to be calculated. And Wp is dependent on the size of PV panel as well as on the climatic conditions of that particular location. For India, ‘panel generation factor’ is 4.32. The total watt per day required from the module which is calculated, is then divided by the panel generation factor (4.32) and hence get the total watt peak rating which is required for PV panels to operate the appliances. To find the number of PV panels, we have the total watt peak rating for PV panel and that is to be divided by the rated output watt peak PV of the given module. In our case it is 110 Wp. 3. Determination of sizing of inverter The total watt of the load is not to be equal to the input rating of the inverter. For our considerations of the standalone system, the inverter must be large enough so that it can handle the amount of watt power used at a one time. This is why we keep the inverter size 30-
5. Solar charge controller size The solar charge controller is used for matching the voltage of the PV array and the battery identification is done so that the type of the solar charge controller can also be expected that the which one is correct for our use. There are two types of controllers. One is series charge controller and other is parallel charge controller. The sizing which has to be done for controller that completely depends on the total PV input of current which is delivered to the controller and that too depends on the configuration of the panel (either it is in series or in parallel). According to standard practice in India, for expecting the size of controller is done by the taking the short circuit (Isc) of the PV array and again a multiplication factor of 1.3 is multiplied (to incorporate the loss caused by system). 6. Cost Estimation The total cost of installation of PV system which will reflect the ' pay back calculations ' of solar power PV system. Example of a household is taken 40-Watt two tube lights, used 4 hours per day ISBN-978-81-932091-2-7
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60 -Watt fan, used 8 hours per day One refrigerator, which runs 24 hours per day with compressor or run 12 hours and off 12 hours. The system is assumed to be having power of 12 volts dc, 110 Wp PV module, averagely the sunlight available in a day is 8 to 10 hours per day for equivalent in peak radiation. , factor of 1.3 is taken for incorporation of system loss and losses due to dust and climatic changes , installation of PV system is done in India hence panel generation factor is 4.32. 1. Determination of power consumption = (2 tube lights×40 watt × 4hours per day) + (60 watt × 8 hours per day) + (75 watt ×24×0.5 hours per day) =1700 watts hour per day Required PV panel =1700× 1.3 = 2210 watt hour per day 2. Determination of sizing of PV panel Total peak watt of PV panel as per its capacity= 2210/4.3 = 513.95 Wp =550 Wp (on rounding off) Number of PV panels required=550/110 Required number of modules =5 modules This system if have at least 5 modules of 110 Wp PV module then work properly. 3. Determination of sizing of Inverter Total watt power of appliances is =2×40+60+75 =215 watt Due to safety purposes, considering size of inverter to be 30-35%bigger Hence inverter should be at least of 290 watt. 4. Determination of sizing of battery Appliance use of watt is =1700-watt hour per day Nominal voltage of the battery is =12 volts Days of autonomy considered is =3days Battery capacity will be
= (1700×3) ÷ (0.85×0.6×12) The total ampere hours required for our module is =833.33Ah Hence the battery should be rated, 12 volts 900Ah of for 3 days autonomy. 5. Determination of Solar charge controller The specifications of PV module at nominal operating cell temperature (NOCT) are as follows: P=110 Wp V =16.7 V I=6.6A Voc=21.3 V (Voc is open circuit voltage) Isc=7.5A (Isc is short circuit current) Rating of solar is given by = (5 strings×7.5A) × 1.3 =48.75A Hence the solar charge controller on making it round off should be of at least 50 ampere. 6.
Cost estimation Cost of arrays is =number of PV modules× cost per module =5×12000=Rs.60000 Cost of batteries is =number of batteries× cost per battery =1×15000=Rs.15000 Cost of inverter is =number of inverters× cost per inverter =1×10000 =Rs.10000 The total cost of system is 60000+15000+10000=Rs 85000 (Additional cost of wiring may also be taken consideration) Payback calculations of solar PV system In normal electricity bills Rs per unit or kWh is 6.5 is assumed and on monthly basis if average rupees 1000 bill comes then per year Rs is 12000 required to pay bill which includes some ISBN-978-81-932091-2-7
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fix money which also has to be paid to power grid companies. In 7.08 years the amount of Rs 85000 will be paid in normal electricity bills. Benefits of solar PV system are Solar PV panels can give us clean, green energy. As there are no harmful emission of gases from solar PV system. Solar energy is free in nature and in abundant amount and can be utilized at great extent. PV panels give us the direct electricity generated with the help of photoelectric phenomenon. Residential solar panels are of not so large size and are easy to install PV modules does not contain any moving parts so they degrade very slowly and average life of PV is boosted. Limitations of solar PV system Efficiency of solar panels are comparably low from other electric power systems. These solar panels are less reliable as many persons are unaware of its benefits. Installation of such PV system is quite costly. When a continuous supply of electric power is required, these solar panels are less efficient in storing and giving energy.
APPLICATIONS OF SOLAR PV SYSTEM Thermoelectric refrigeration driven by solar.
Solar nanowires working with infrared spectrum. Microcomputer based control of a residential photovoltaic power system Imagine a future in which we are having solar cells all around us, on windows, walls, laptops. Such transparent photovoltaic cells are already being developed by MIT scientists, giving us advance solar technologies. CONCLUSION
The geographical location of India country can stand for the tremendous scope in generation of solar energy and its utilization so as to achieve its maximum benefits and to provide nationwide development in power and reducing costs of power expenditure of India. With the advancement and development of India, implementations of several new plans will establish solar grids. And in that, this renewable energy is playing promising role not only in India but in world. As the example coated of household where solar PV panel system gives us the idea of money saving when compared to normal bills paid in power grid systems of nonrenewable sources. We saw 85000 rupees were required to install a solar panel and it will become our own power generation system in 7.08 years whereas in other case family is expected to pay bill for lifetime. If such huge step of using solar energy is taken for world then this will be the actual advancement in the field of power systems in respect to generation, transmission, and distribution. Table 1: Financial cost effectiveness for various Gol policy instruments for 1MWsolar PV installed in 2016-17 Fig.1: Complete PV system Fig.2: Major components of PV system References 1. www.dummies.com 2. www.leonics.com 3. www.solardirect.com 4. www.solartown.com 5. www.wikipedia.com 6. M. Tripathi ,S.Yadav ,P.K.sadhu,S.K panda -Renewable Energy 7. Chetan Singh Solanki-Renewable energy technologies: a practical guide for beginners 8. Renewable Energy Systems: Advanced Conversion Technologies and Applications 9. Real Goods Solar Living Sourcebook Your Complete Guide to Living beyond the Grid with Renewable Energy Technologies and Sustainable Living (14th edition) ISBN-978-81-932091-2-7
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10. Renewable energy technologies (Energyefficient house) 11. IEEE Press series on power grid engineering by Digambar M. Tagare 12. Renewable energy technologies by Jean Claude sabonnadriere
13. Solar Electric Power Generation Photovoltaic Energy Systems: Modeling of Optical and Thermal Performance, Electrical Yield, Energy Balance, Effect on Reduction of Greenhouse Gas Emissions
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An Assessment of Wind Power Potential in Astana: A Wind Power Plant Feasibility Study for Akmola Region, Kazakhstan
Abduvakhit Junussov, Ainur Rakhymbay, Dhawal Shah2, Prashant K. Jamwal1, * 1 Department of Electrical and Electronic Engineering, and 2Deparment of Chemical Engineering, Nazarbayev University, Astana, Kazakhstan Corresponding Author: prashant.jamwal@nu.edu.kz Abstract Kazakhstan has a huge capacity of natural resources such as coal, oil, natural gas, uranium and great renewable energy potential from solar, wind, hydro-power and biomass. However, the country is still dependent upon fossil fuel for energy generation and 75% of total produced energy comes from coalfired power plants, which contributes to greenhouse gas emission and environmental problems [1]. The development of power plants based on renewable energy is still on small scale since the upfront investment is very high, while the internal rate of return is low. While dynamic growth of Astana city has driven increased demand for energy supply, the existing power plants in Central and Northern Kazakhstan have been already overused and are old. Therefore, construction of new wind farms near Astana is an attractive solution, which can boost energy capacity of region and gradually decrease CO2 emissions. The aim of this research is to assess the wind energy potential of Akmola region along with the investigation on the development of energy and cost-efficient wind power plant. In particular, the wind energy potential of this region with the specific site characteristics has been analyzed. The design of wind farm is presented with appropriate layout and power conditioning and utilization schemes. Simulations in MatLab/SIMULINK software are conducted to reveal energy efficiency of the proposed wind farm. Finally, a financial analysis with environmental impacts is discussed. In conclusion, the feasibleness analysis of wind farm construction is revealed as a model procedure. I. INTRODUCTION Kazakhstan is the world’s ninth largest country, which was founded after the dissolution of the Soviet Union in 1991, with more than 2.7 million km2 land area and 17.4 million unevenly spread population, where 47% of people living in rural terrains [2]. The Republic of Kazakhstan is a Central Asian country with continental land mass, where a steppe grassland and pastureland dominates in the North regions, desert and semidesert are characteristic to the Central regions, the Southern part of country are covered by mountains such as Tien Shan and Pamir, and Western regions consists of catchments of Caspian and Aral Seas. The total land for agricultural sector is 76.5 million hectares, where the share of permanent pastures is 64%, while the 32% are arable lands for various
grain production [3]. This country is characterized by the continental climate, where the winters are cold with average temperature of 18.5°C in North regions and -1.8°C in South regions in January, and summers are hot with average temperature of 28.4°C in south and 19.4°C in north in July [4]. The continental type of climate requires space heating in cold winter periods and air conditioning in hot summer times, which contributes to the increasing demand on energy supply. The largest contribution to the economy of Kazakhstan comes from its natural resources such as oil & gas and uranium, heavy industry such as production of ferrous and non-ferrous metals and agricultural segment. The mining and petroleum ISBN-978-81-932091-2-7
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industries accounted for 42% of GDP in 2016 and 85% of country exports [5]. Generally, GDP of Kazakhstan increased from 19.5 billion USD in 1991 to about 184.39 billion USD in 2017 with the highest 236.6 billion USD rate in 2001. The annual GDP rate has varied between -11.1% to 16.9% since the foundation of Republic of Kazakhstan as illustrated in Fig.1. The positive and significant increase in GDP and per capita income has resulted to the reduction of poverty in the country from 47% in 2001 to approximately 5% in 2014. However, the rapid economic growth has led to the huge increase in energy demand, particularly in winters. According to UNDP [6], the energy consumption of Kazakhstan (in metric tons of oil equivalent) has increased from 25.93 mtoe in 2000 to 92.3 mtoe in 2016, whereas the total power production has raised from 46 TWh in 2000 to about 94 TWh in 2016. Currently, the total capacity of energy production is 20.1 GW where only about 16 GW is usable and losses occur due to poor maintenance, grid connection and equipment aging [7]. The 78.44% of produced power generated from thermal power plants, 7.86% comes from gas power stations and 7.86% produced from hydropower stations. Unfortunately, the percentage of power generation from renewable energy sources such as solar, wind, biomass accounts for only 0.4% of total energy production [8]. However, Kazakhstan has a huge potential to generate electricity from the renewable resources and government expects to increase renewable energy production by 11% in 2020.
Figure 1. Kazakhstan’s GDP annual growth rate [5]
Mainly, the total production of carbon dioxide emissions in Kazakhstan is 235 MtCO2 in 2016 and 80% of it has resulted from the heat and electricity generation plants [9]. Therefore, it is crucial to increase the total share of energy production from environmentally friendly and efficient renewable energy sources in order to achieve sustainable development and meet the rising energy demand of the country. In addition, Kazakhstan has signed the United Nations Framework Convention on Climate Change and is going to accept Kyoto Protocol, which states improving energy quality for the environment protection along with the sustainable economic development [4]. Global Environmental Facility along with United Nations Development Program (UNDP) and government of Kazakhstan are investigating on the discovery and development of wind power implementation opportunities in Kazakhstan [10]. In fact, the attraction of investors from several international companies and organizations to the development of wind power generation is not only due to the intention to decrease greenhouse gas (GHG) emissions but also there is an excellent chance to develop a profitable business in this sector. According to GEF-UNDP wind resource assessments, Kazakhstan has an exceptional potential of wind resources. Particularly, observations have revealed that almost a half of Kazakhstan’s territory has a wind with 4-5 m/s average speed at a height of 35m [11]. The windiest sites of country are western regions near the Caspian and Aral seas, central regions as well as some south regions. It is estimated that the annual production of power from wind turbines could reach an 8-10 TWh. Hence, the construction of wind farms will fulfill the expanding energy shortages of the country as well as contribute to less environmental pollution and impact on population health. This feasibility report investigates on the assessment of wind farm implementation in Astana city. In section II, a case study of Astana city with detailed description of climatic conditions is reported. Moreover, this section includes the recent trends on energy production ISBN-978-81-932091-2-7
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and energy demand of Astana city along with the grid connection possibilities. Then, section III proposes the layout of wind farm by describing and selecting the most efficient wind turbines and energy storage system. Section IV provides economic analysis as well as assess possible impacts caused by wind farm. At the end, conclusion is given by suggesting whether it is feasible to build a wind farm in Astana city or not. II. SITE DESCRIPTION The proposed location for wind farm construction is situated within of 5 km of the edge of the city with 51°08’ latitude and 71°28’ longitude. The area of selected site is about 8x10 km2 with the capacity for further wind farm expansion. It is estimated that this land is capable to produce up to 50 MW power.
Figure 2. The wind farm location in Astana city The selected site lies in south part of Astana city and 1.5 km apart from the southward residential villages, as shown in Fig.2. The proposed area for wind farm construction is in close proximity to highway road line, which is beneficial for the transportation of wind turbines to the site and fast response to maintenance works. Moreover, the city’s airport station is located 16 km apart from the proposed site, and the flight path is in SW-NE direction which will not disturb the function of wind farm. In addition, the 110-kV high voltage transmission line is adjacent to the wind farm location and also there is a large power substation within 1 km distance apart. A. Climate features of Astana
As mentioned above, Astana is characterized by sharp continental climate with extremely cold winters and dry warm summers. The main feature of continental climate is the significant changes of air temperature, dry air and a small amount of precipitation. The annual average temperature is 3.2°C and the average rainfall is 307 mm [5]. The duration of cold time is on average 165-170 days with a daily air temperature below 0°C. The hottest period is in July with an average air temperature of 20.9°C, whereas the coldest period in January with an average air temperature of 15.2°C. Figure 3 illustrates the average air temperature and the average rainfall in each month of Astana.
Figure 3. The average air temperature and rainfall of Astana [5] B. Assessment of wind resource The lack of protection from the penetration of various air masses and relatively flat terrain results to the favorable wind speed. The strong wind speeds are typical for spring and summer periods. The average monthly wind speed for Astana varies between 4.0 m/sec to 6.3 m/sec [11]. The days with strong winds up to 15 m/sec ranges from 10 to 50 days per year, while the windless days varies between 50 to 70 annually. The direction of wind in winter periods are to the south and in summer periods to the north. The table 1 lists the average monthly wind speeds of Astana. ISBN-978-81-932091-2-7
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TABLE I. Average monthly wind speeds in Astana [11] Month January February March April May June July
Wind Speed (m/sec) 5.2 5.1 5.4 5.2 5.0 4.4 4.1
Month July August September October November December Annual
Wind Speed (m/sec) 4.1 4.0 4.1 5.1 5.3 5.1 5.8
In 2013 the UNDP [6] have conducted a research toward the identification of wind power potential in Astana city. The average wind speeds at heights of 80 m, 51 m, 49 m and 22 m above the ground level were monitored by using a tubular tower with installed anemometers. In this research, the data taken from these measurements have been used for the feasibility analysis of wind farm in Astana. Table 2 provides the results of measurements conducted by UNDP. TABLE II. Wind speed measurements at height of 80 m, 51 m, 49 m and 22 m [6] Measurements Minimum wind speed (m/s) Maximum wind speed (m/s) Average wind speed (m/s)
Level 1 (80 m)
Level 2 (51 m)
Level 3 (49 m)
Level 4 (22 m)
0.2
0.2
0.2
0.2
27.5
26.6
26.7
24.3
7.25
6.51
6.48
5.39
Astana is characterized by the repeatability of high wind speeds and in cold periods of year the wind is caused by western spur of the Asian anticyclone [4]. Therefore, the direction of wind in Astana predominantly is south-west, as demonstrated in energy rose map (Fig. 4). As a result, the majority of wind power initiated from the south-west direction.
Figure 4. The wind direction and wind energy distribution for Astana [4] Moreover, the efficiency of generated wind power is also influenced by the number of atmospheric phenomena such as thunderstorms, hails, blizzards, snowstorms and dust storms. The storms are more frequent in summer and less frequent in fall and spring. The annual average number of days with thunderstorm is 23, the average frequency of snow storms is about 38 days per year. The occurrence of days with blizzard varies between 20 to 50 on average per year, whereas the days with dust storms meet 60 times on average per year. C. Energy production and consumption Currently, the total power production from the installed plants in Kazakhstan is 18.992 TW. The percentage of electricity production from thermal power plant is 87.7% and the rest 12.2% comes from the hydroelectric power plant. About 70% of energy is produced by burning a coal, 14.6% energy generation from hydro resources, 10.6 % from gas, 4.9% from oil, whereas only 0.4% comes from the solar and wind resources [1]. The huge percent of generated power is consumed by the industry, which is about 68.7%. The domestic energy consumption is 9.3%, the agricultural sector consumes 1.2%, the transportation system uses 5.6% from total production. The leaders of energy production are Pavlodar and Karaganda cities, which are located near the coal mines [14]. Figure 5 demonstrates the distribution of electricity production level among all regions and cities of Kazakhstan.
Figure 5. The total generation of electricity by regions [14] ISBN-978-81-932091-2-7
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The energy consumption differs among cities of Kazakhstan. As Karaganda, Pavlodar, East Kazakhstan cities have industrial factories, they consume the most part of produced power. Akmola region along with Astana city consumes approximately 5 200 000 MWh energy. There are two working combined heat and power plants in Astana (CHP-1 and CHP-2), which produce 22 MW and 360 MW of power respectively. However, this produced amount of energy is insufficient for the total demand of fastest growing capital of Kazakhstan. Therefore, the huge amount of electricity comes from Pavlodar and Karaganda in order to fulfill the energy requirements of Astana. The seasonal energy consumption of Astana is shown in figure 7, where the most electricity is consumed during winter periods [12].
Figure 6. The energy consumption by regions [15] Jan Feb March Apr May June July Aug Sept Oct Nov Dec
Figure 7. The monthly power consumption of Astana [12] The electricity tariffs in Kazakhstan varies in different cities depending on the transmission distance, the percentage of occurred losses,
operation and maintenance cost of region. The electricity price in Astana is 12.99 KZT/kWh for the domestic consumption and 18.1 KZT/kWh for other purposes [15]. The total length of high voltage electrical lines is more than 5500 km for 500 kV, more than 20 200 km for 220 kV, 44 500 km for 110 kV, 62 000 km for 35 kV and approximately 204 000 km for small 6-10 kV lines [13]. The power loss during the transmission and distribution accounts for 21.5 %, which is significantly. Particularly, the Akmola region has 4300 km total length of high voltage grid lines, 10 substations with the total grid capacity of 7800 MVA. III. DESIGN OF WIND FARM Wind turbines A wind turbine is a mechanical machine that converts the kinetic energy of the wind into mechanical by induced rotation of rotors blade [16]. After that, generators convert produced mechanical energy into desired electrical energy for further consumption [16]. As the wind turbines form the basis of wind farm, the proper selection of them is a major concern. Generally, there are two types of wind turbines used for power production based on axis of the turbine rotation: Horizontal Axis Wind Turbine (HAWT) and Vertical Axis Wind Turbine (VAWT) (see Fig. 8). A.
1. Horizontal axis wind turbine The horizontal axis wind turbine uses axis parallel to the ground for a rotation. The structure of horizontal axis turbine consists of a rotor, blades, gearbox, generator located at the top of a turbine tower, and the blades faced towards the wind [16]. The shaft of a turbine starts rotating when wind hits the blades, and then gearbox attached to the end of the shaft turns a slow rotation of blades into faster rotation to drive generator [16]. Horizontal axis wind turbines are more popular compared to vertical axis wind turbines. Table III provides advantages and disadvantages of HAWT. ISBN-978-81-932091-2-7
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TABLE III. Advantages/Disadvantages of HAWT [16] Advantages High efficiency Installation is self-starting High stability Rotor blades can be pitched Variable blade pitch
Disadvantages Hazards for low height crafts Difficult maintenance Difficult transportation Turbulence may cause fatigue Bad aesthetic view
2. Vertical axis wind turbine The vertical wind turbines use axis perpendicular to the ground for rotation. The main difference of this type is that this type of wind turbine does not need to be faced towards the wind, and its efficiency does not been affected by change of the wind flow direction [16]. Moreover, all components, such as gearbox, generator, and transformer are placed near the ground. However, due to low efficiency, VAWT is mostly applied in small wind projects, while HAWT is mainly implemented in large wind farms [16]. The following table (Table IV) provides the advantages and disadvantages of VAWT. TABLE IV. Advantages/Disadvantages of VAWT [16] Advantages Ease of maintenance Better aerodynamics Ease of transp. and install. The efficiency is stable No need of yaw device
Disadvantages Only low heights Low efficiency Additional energy to start rotation Causes drag Flat surface is required
So, from tables (Table III & IV), it can be seen that HAWT is more suitable and preferable than VAWT, for producing large amount of energy. HAWT has higher efficiency, it is more stable, and provides more warranty. B. Choosing wind turbine type It was stated above, that chosen location has potential of producing about 50 MW of energy. So, in order to achieve that, it is necessary to choose the wind turbine which will fulfill requirements of location, such as wind speed, air density, and so on. Average wind speed is given in Table I, it is important to choose the wind turbine, which will be able to operate at low wind speed, and which will have low cut-out speed to prevent damage of turbine during the strong winds. After some evaluations, Vestas V112 â&#x20AC;&#x201C; 3.3 MW horizontal axis wind turbine was chosen. Its specifications are provided in Table V.
TABLE V. V112-3.3 MW description [17] Operating Data Rated power Cut-in wind speed Cut-out wind speed
3.3 MW 3 m/s 25 m/s
Table V shows that Vestas V112 is able to operate at minimum wind speed 3 m/s, and if wind speed will be higher than 25 m/s, it will stop operate. Since one wind turbine is going to produce about 3.3 MW of energy, it is required to use 15 of them to generate 50 MW of energy. C. Wind farm layout In order to get higher profitability from the wind system, it is important to adequately design wind farm layout. The careful and detailed optimization of layout contributes to maximum wind power capture. Here is the cost of energy calculation equation: â&#x2C6;&#x2014; đ??śđ?&#x2018;&#x153;đ??¸ = +đ??ś & (1) Where, C1 is initial capital cost of wind farm, FCR is fixed charge rate, Cr is replacement cost, Cq&m is cost of maintenance and operation, AEP is annual energy production. From the equation 1, it can be seen, if the annual energy production is increased, the total cost of energy will be minimized. â&#x20AC;&#x153;One of the main problems that cause the wind power capture reduction is a phenomenon known as a wake loss. When incoming wind encounters a wind turbine, a linearly expanding wake occurs behind the turbine [16]. Thus, the speed of free stream wind is lowered. The phenomenon is illustrated in Figure 8. The effect of wake loss on several turbines is illustrated in Figure 9. Therefore, it is apparent that the problem of design optimization is mainly concerned with locating wind turbines so that they are not affected by wake loss.â&#x20AC;? So, there are different computer software which provide an algorithm for the layout design. The algorithm uses different parameters, such as number of turbines, planned area, height of the turbine, average wind speed, temperature of the air, grid connections, loads, and etc., to get maximum annual energy production from the wind farm. ISBN-978-81-932091-2-7
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Figure 8. Wake loss [16] Figure 10. Astana wind farm design
Figure 9. The effect of wake loss on wind turbines [16] By using Homer PRO software, the optimal wind farm layout was found (see Fig. 10). D. Grid connection It is important to connect each wind generator to the grid. Therefore, availability of the grid close to the wind power plant site has to be considered during selection of the location for power plant. However, it is not enough to build a wind farm, and just connect to the grid. The power plant has to fully comply with grid requirements. As the wind power is not stable during the year and occurrences of power loss, it may bring a risk to the reliability and stability of the entire power system. Therefore, before implementation of wind farm set of rules must be met and accomplished such as frequency, reactive power, power factor controls, voltage, and transient fault behaviors. Moreover, people responsible for developing wind farm should contact local Transmission System Operators. In case of meeting all set of requirements Electricity Grid Company (TSO) will provide with necessary documents for Power Purchase [18]. E. Matlab/Simulink Simulation
Figure 11. The Simulink model for wind turbine
Figure 12. Wind farm simulation results
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Here is the Simulink model for wind turbine simulation (see Fig. 11). The simulation provides the turbine output power, and wind speed.
calculated to be approximately 7 years (see Fig. 12).
For simulation, the wind speed was taken as sinusoidal wave, with peak values equal to 30, which is maximum possible wind speed in the region. So, Fig. 12 provides two graphs: one for wind speed and another one for power output. It can be seen that, when wind speed reaches to 3 m/s, wind turbines start to produce energy, and when wind speed reaches to 25 m/s (cut-out speed) then wind turbines stop to generate energy. There is a point on figure, when turbines start to generate constant amount of energy. This wind speed is known as rated output speed. At that speed turbines reach to their maximum point, and operate in stable condition. IV. FINANCIAL ANALYSIS Every project requires detailed financial analysis, in order to estimate how much it will cost, and how long it will take to pay-off it. TABLE VI. Capital cost Turbines + Installation & Transportation Storage blocks Maintenance Inflation Total cost
48 250 000$ 1 173 000$ 4 630 000$ 12% 54 053 000$
TABLE VII. Operational revenue Electricity cost Average electricity growth cost Required energy Average growth of electricity cons Corporate income tax Cost for electricity
0.0565$ 8% 180 000 MWh/year 4.5% 12% 10 170 000
Tables above (Table VI and VII) provide the capital cost and operational revenue of the project, respectively. The financial expenses for the first year of the project include cost of land, storage blocks, installation & maintenance of all 15 turbines, and transportation. Also, it was estimated that due to inflation, each year capital cost of the project will increase by 12%. It can be seen from Table VII, that cost for electricity is not high, but with increase of electricity consumption and average electricity cost, pay-off period was
Figure 12. Total cost vs Total income V. ENVIRONMENTAL IMPACTS It is known that wind energy is one of the cleanest and safest of the renewable energies. However, it still has negative effect on the environment. Of course, the effects are considered to be minor, but they still have to be analyzed to provide reasonable evaluation for the project. The environmental impact can be divided into three main categories: 1) Land pollution: According to [19], during the construction and operation about 14164 m2 of land per 1 MW is affected. Moreover, about 4047m2 of land is always in use, and it can spoil the soil. However, the spoiled soil still can be used for pasture or agriculture [19]. 2) Wildlife: It is known that the wildlife on Kazakhstan is very wide and diverse. To be precise, there are about 150 species of birds and 9 species of bats in the North part of KZ, which periodically fly close to Astana [20]. As it is stated in [21], it was scientifically proven that turbines cause deaths and injuries to those species. The damage can be explained by changes in landscape and pressure drop near wind farms [21]. However, those studies state that the casualties are low, if the wind farm doesn’t stay on the route of migration of birds. According to [22], there no migration roads in Astana, so wild plant has to be safe for wildlife. 3) Water and air pollution: Water is mainly used only during construction process, so the water is not polluted much. In case of the air, it also has ISBN-978-81-932091-2-7
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effect only during construction period. Moreover, during the operation of wind farm, there is heat emission, which is also has to be taken into account. However, this emission is much lower compared to other sources of emission, such as natural gas and coal [23]. VI. CONCLUSION During this feasibility analysis, it was necessary to analyze potential of wind power in Astana, Kazakhstan. Site for construction was chosen close to the edge of the city (5 km), and at the same time close to high voltage transmission lines. The detailed analysis of construction site was conducted. All important factors, such as wind speed, wind turbine type, annual energy consumption of city, meteorological factors, were considered during this research. It was proposed to use 15 Vestas V112 horizontal axis wind turbine with rated power 3.3MW, in order to produce 50 MW of energy. This type of turbines provides efficient, reliable, and stable amount of energy even during the low speed of wind. In order to get maximum profitability from the research, layout of the farm was also analyzed by using Homer Pro software. Moreover, during this research economical side of the project was discussed, and it was found that it will take approximately 7 years to get payback from the project. Finally, environmental impact of the wind farm was analyzed, and it was found that on chosen location, farm will not cause side effects on environment. So, for the future the wind power plant can be improved to make it more echo and society friendly. First of all, noise of the turbines could be reduced by using more advanced prototypes of blades. Also, to improve security of the farm, internet of things can be applied, which will allow to control the wind farm 24/7, even if being on another side of the planet. Finally, with increase of the annual energy consumption, it will be necessary to expand the farm to fulfill energy needs of the city. REFERENCES [1] M. Karatayev, M.L. Clarke, 2016, ‘A review of current energy systems and green energy
potential in Kazakhstan,’ in Renewable and Sustainable Energy Reviews, Vol. 55, pp. 491–504. Available at http://www.sciencedirect.com/science/articl e/pii/S1364032115011570 [2] Agency of statistics of the Republic of Kazakhstan. Demography and migration: an outlook for 1991–2016.Available at www.stat.gov.kz [3] USDA. Kazakhstan: agriculture overview. U.S. Department of Agriculture. Available at: www.pecad.fas.usda.gov [4] E. Danayev. (2008). Feasibility of Wind Energy Development in Kazakhstan. Available at http://www.esru.strath.ac.uk/Documents/M Sc_2008/Danayev.pdf [5] Kazakhstan GDP Annual Growth Rate. [Online]. Available at http://www.tradingeconomics.com/kazakhs tan/gdp-growth-annual [6] Prospective of Wind Power Development in Kazakhstan. (2006). UNDP/GEF and Government of Kazakhstan wind power project, available at http://windenergy.kz/files/1214226182_file .pdf [7] International Energy Statistics. [Online] available at https://knoema.com/EIAIES2015Jun/intern ational-energy-statistics-january2016?location=1001060-kazakhstan [8] L. Parchomchik. (2017). Electricity Generation in Kazakhstan: Current Trends and Prospects. Available at http://eurasianresearch.org/en/research/comments/energy/ electricity-generation-kazakhstan-currenttrends-and-prospects [9] Global Carbon Atlas. [Online]. Available at http://www.globalcarbonatlas.org/en/CO2emissions [10] Wind Atlas of Kazakhstan. (2013). UNDPGEF project, available at https://globalatlas.irena.org/UserFiles/cases tudies/IRENA_Case_Kazakhstan.pdf [11] J. Cochran. (2008). Kazakhstan’s Potential for Wind and Concentrated Solar Power. ISBN-978-81-932091-2-7
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[12]
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Available at https://www.kimep.kz/css/files/2014/07/Co chran_Wind_and_Concentrated_Solar.pdf Atakhanova Z., Howie P. (2007) ELECTRICITY DEMAND IN KAZAKHSTAN. Energy Policy, 35, p. 3729-3743. Available at http://www.sciencedirect.com/science/articl e/pii/S030142150700016X KEGOC. (2016). Annual Report 2015. Astana. Available at http://www.kegoc.kz/en/shareholders-andinvestors/information-disclosure/generalmeetings/2015 KOREM. (2016). Report on the results of monitoring electric energy market and centralized bidding for 9 months of 2016. Astana. Electricity tariffs in Astana. (2017). Available at http://www.astanaenergosbyt.kz/tarif Patnaik, I. (2009). Wind as a renewable source of energy. Retrieved March 20, 2015 from: http://ethesis.nitrkl.ac.in/1420/1/thesis_of_i shan_ patnaik(10502038).pdf Vestas Wind Systems A/S. (2014). V1123.3 MW™ at a Glance. Retrieved February 15, 2015 from http://www.vestas.com/en/products _and_services/turbines/v1123_3_mw#!at-aglance Teodorescu, R., Liserre, M. and Rodriguez, P. (2011). Grid converters for Photovoltaic and Wind Power Systems. John Wiley & Sons, Ltd: United Kingdom. Denholm, P., Hand, M., Jackson, M., and Ong, S. (2009). Land-use requirements of modern wind power plants in the United States. Retrieved March 15, 2015 from http://www.nrel.gov/docs/fy09osti/45834.p df Kuznetsov, B. (1975). Key to vertebrates fauna in USSR. Prosveshenie. Retrieved March 15, 2015 from http://zoomet.ru/kyz/kyznesov_
2_2.htmlhttp://zoomet.ru/kyz/kyznesov_2_ 2.html [21] National Wind Coordinating Committee (NWCC). (2010). Wind turbine interactions with birds, bats, and their habitats: A summary of research results and priority questions. Retrieved March 15, 2015 from https://nationalwind.org/research/publicatio ns/birds-and-bats-fact-sheet/ [22] Advantour (2015). Unique natural scenery of Northern Kazakhstan. Retrieved March 5, 2015 from http://www.advantour.com /rus/kazakhstan/northern.htm [23] Edenhofer, O., Madruga, R. and Sokona. Y. (2012). Renewable Energy Sources and Climate Change Mitigation. Retrieved March 9, 2015 from http://srren.ipccwg3.de/report/IPCC_SRRE N_Full_Report.pdf
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Energy efficiency of PV panels under real outdoor conditions – An experimental assessment in Kazakhstan Ali Mubarakov1, Sanzhar Sultan1, Nurzhan Arkabayev1, Dhawal Shah2, Prashant K. Jamwal1,* 1 Department of Electrical and Electronic Engineering, and 2Deparment of Chemical Engineering, Nazarbayev University, Astana, Kazakhstan.*prashant.jamwal@nu.edu.kz
Abstract This paper provides an analysis of temperature effect on the performance of solar panels. Specifically, wider temperature range which prevails in Astana, Kazakhstan is considered. Previous work related with PV cell performance under extreme weather conditions had been carried out on a single PV panel in different temperature ranges. However, in the present research the performance, conversion efficiency and maintenance of different PV panels in Astana weather conditions are investigated. MATLAB simulation using existing PV panel models have been performed with various climate conditions and compared with the real data which is collected from Alfa-solar PV panels situated in techno-park of Nazarbayev University, Astana. Homer software® is used to assess financial aspects of PV system. The results from this research can help significantly in the evaluation of solar panels application in extreme conditions. INTRODUCTION Direct utilization of solar energy as power source have already experiencing massive worldwide commissioning and installation of PV plants, from 5W panels to supply rural lighting to large systems for modern towns. Massive adoption of new technologies, on the other hand, leads to additional issues formerly unaddressed and invisible. The current research in this area remains focused on mono and poly Si cells, because most of the PV systems nowadays are based on this technology. Further, PV panels works with higher efficiencies in direct sun irradiation with less obstacles and if cells are maintained at low temperatures. The location of installation (longitude, altitude and latitude) foremost defines the solar power accessible for a fixed PV panel. The terrain, exposure, and common environmental conditions also sufficiently impact the performance of the PV panels. Particularly, the dust has the strong obvious effect on PV panel efficiency [1]. The size of the PV system and the prevalent wind circulations would also define whether wind alleviates or aggravates dust settlement, in addition to heat exchange process.
I.
II.
LITERATURE REVIEW
Influence of dust The influence of dust on the performance of Si PV panel is studied in [2]. Depending of amount, density and composition of dust, it can have different impact on the output panel. In particular, small amount of dust could actually benefit overall performance due to fact that it adsorbs part of unwanted wavelength of solar irradiation. This in turn results lower temperature of solar cells, and thus higher efficiency of the system (Fig. 1). In addition, this small particle of dust only catches undesirable light wavelength, while other ranges can participate in electricity generation. In fact, Si based panels generates electricity only with visible spectrum, whereas the rest converted to heat the system which can be stored by dust particles on the surface. As a result, utilizing this feature could also decrease the frequency of cleaning process of PV panels as well, through analysis of data from monitoring system. On the contrary, larger amount of dust on the top glass of the PV panel does not allow the light to reach the cell, resulting lower efficiency of the system.
A.
B.
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In [3] mathematical model of mono-crystalline Si PV cell is devised using classical single diode model. There solar cell is considered as a current source which produces current proportional to the irradiation capacity. In the suggested model, series Rs and shunt Rsh are responsible for ohmic losses in panel.
Fig. 1. Temperature difference between dusty and clean PV panels Further this model is implemented in LabVIEW, which allows to study major PV panel parameters under different values of solar irradiance and cell temperature. In particular, designed simulation project calculates and plots power-voltage, current voltage curves, as well as system efficiency, fill factors (FF), open-circuit voltage, etc. The simulations are carried out under constant irradiance of 1 kW/m2 and varying temperatures. In terms of results, well consistency with datasheet approves model accuracy. In addition, proposed design is flexible, and can be utilized for PV cells from different manufacturers. The effects of solar irradiance and temperature on the performance of different types Si solar panels are discussed in [4]. Particularly, solar intensity had been changed from 0.2 to 1.0 Sun, and have significant impact on current behavior. All of the following parameters including short circuit, photo current and maximum current increase linearly as solar irradiance goes higher. Therefore, the significance of concentrating system is noted which allows increase the output capacity. However, as it is revealed, without cooling option output power of the system also declines. Owing t o concentrated light a n d more heat, temperature of PV cells goes up. This decreases
open circuit voltage and maximum voltage. The maximum output power falls by 14 to 25 per cent for poly and mono crystalline Si, under module temperature range of 10◦C500◦C. A solar panel is a device, which consists of PV cells that are connected in series and parallel. Partial shading is a condition, when part of PV cells is covered by clouds or by the shadows of nearest buildings. Under this condition, received solar irradiance of different PV cells varies. For each value of solar irradiance, a PV cell is able to produce current, that it less than its short circuit. Hence, if two parallel connected PV cells obtain different irradiances, reverse bias operation of several PV cells occurs. This condition brings hot spot formation in PV panel. Utilization of bypass diodes is one of the solutions of this problem. Operation of bypass diodes leads to appearance of multiple peaks in power curve. Therefore, partial shading condition leads to transformation of electrical characteristics of PV panel, comparing it to same of PV panels under normal conditions [5]. C. Effect of air velocity and humidity The work of Mekhlief and Saidur has also considered such factors as air velocity and humidity that has a minor effect on PV performance [6]. The originality of their paper is in study of their effects in parallel and how they interact with each other. The air velocity was related to the temperature of the cells. As wind velocity increases cell temperature will decrease, as a result PV cell efficiency will increase. In addition, it was mentioned that performance is heavily dependent on cell type. Effect of humidity was considered in two different ways; first one affected irradiance level, while second one is ingression of humidity to cell enclosure. Also, two module failure types and their impact on short circuit current and open circuit voltage were reported [6]. The effect of varying climates was described by Hermann and Bogdanski. Climatic impacts were considered in terms of three parameters, ISBN-978-81-932091-2-7
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as irradiation, ambient temperature and relative humidity. The test sites were Germany (moderate climate), Indonesia(tropical climate), German Alps (high mountain cli- mate) and Neged Desert of Israel (arid climate). The main objective of paper was to develop accelerated laboratory testing, to predict cell performance after 25 years of performance. The results from testing show that same cells have different degradation types [7]. PV field performance under different environmental conditions and atmospheric parameters was considered by Micheli, Muller and Kurtz. The main focus was made on soiling losses with complex mechanisms and interactions. PV cells were located in different locations to identify the most influencing factors that result in accumulation of dust. The calculations included such parameters as airquality indexes, amount of rainfall, climate zone and recurrence [8]. III. METHODOLOGY A. Data collection In order to make an assessment of PV panels under real outdoor conditions in Astana, data from real existing PV panels have been collected and processed. Two PV plants that have been observed are located in Technopark at the Nazarbayev University, Astana. Their capacities are 10 and 15 kw. Current in phases A, B, and C of these 10 and 15 kW solar plants have been recorded within the month of January and March. Recording was conducted for every 30 seconds from 9 AM to 7 PM, due to the fact, that current during night is close to zero. After that, from all the numbers collected, average value for each day was received by using MS Excel. By using received data, graphs that are provided were plotted.
Fig. 2. Change of current in 10 kW and 15 kW
PV plants within January. Fig. 2 illustrates the change of current of 10 kW and 15 kW plants within a January. Current that was generated by 15 kW plant is bigger, than current that was generated by 10 kW plant. 10 kW plant produces relatively stable current, with average value around 4 A, with only fall on the 25th and 26th of January. At the same time, current of 15 kW plant is fluctuating during observed period, from less than 2 A to more than 11 A, which may be caused by several conditions, such as dust on the PV panel. On the 25th and 26th of March both PV plants showed poor performance, which was dictated by extremely cloudy weather in Astana.
Fig. 3. Change of current in 10 kW and 15 kW PV plants within March. As it is clear from Fig. 3, currents in phases A, B, and C are almost equal, and cannot be distinguished. Obviously, 15 kW solar power plants have higher current values, than 10 kW solar power plants. A 15 kW plant has values of current nearly 10 A during observed period, whereas average value of 10 kW plant is around 7 A. But, on the 2nd, 4th, 8th, and from 22nd to 31st of March, values are lower than average. This may be explained by cloudy weather, with big amount of snow that was present during these days. Table I and Table II illustrate daytime and evening temperatures
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during January and March. Also, drop in generation of current can be caused by dust, which gathered on the PV panel. TABLE I TEMPERATURE IN JANUARY [9] Date 11.01.2017 12.01.2017 13.01.2017 14.01.2017 15.01.2017 16.01.2017 17.01.2017 18.01.2017 19.01.2017 20.01.2017 21.01.2017 22.01.2017 23.01.2017 24.01.2017 25.01.2017 26.01.2017 27.01.2017 28.01.2017 29.01.2017 30.01.2017 31.01.2017
Daytime T(◦C) -12 -12 -18 -14 -13 -13 -12 -7 -8 -13 -11 -11 -11 -14 -6 -4 -5 -6 -10 -7 -8
Evening T(◦C) -16 -17 -18 -16 -17 -19 -16 -12 -10 -14 -13 -17 -14 -14 -6 -6 -6 -12 -12 -13 -8
Description Cloudy, snow Cloudy, snow Cloudy Cloudy Cloudy, snow
Cloudy, snow Cloudy, snow Partly cloudy Cloudy, snow Cloudy, snow Cloudy Cloudy, snow
Fig. 4. Change of temperature within January
Cloudy, snow
TABLE II TEMPERATURE IN MARCH [9] 01.03.2017 02.03.2017 03.03.2017 04.03.2017 05.03.2017 06.03.2017 07.03.2017
Daytime T(◦C) -9 -6 -3 -5 -4 +1 -6
Evening T(◦C) -9 -6 -5 -7 -6 -6 -11
08.03.2017 09.03.2017 10.03.2017 11.03.2017 12.03.2017 13.03.2017 14.03.2017 15.03.2017 16.03.2017 17.03.2017 18.03.2017 19.03.2017 20.03.2017 21.03.2017 22.03.2017 23.03.2017 24.03.2017 25.03.2017 26.03.2017 27.03.2017 28.03.2017 29.03.2017 30.03.2017 31.03.2017
-6 -11 -9 -5 -5 -7 -6 -4 -5 -5 -4 -3 -1 -1 +2 +4 +2 0 +1 +3 +3 +2 0 +4
-7 -12 -12 -10 -10 -10 -19 -6 -11 -11 -10 -8 -7 -8 -5 +1 +1 -2 0 +2 +3 +1 -2 +5
Date
Description Partly cloudy Cloudy, snow Cloudy, snow Cloudy Cloudy
Cloudy, snow Cloudy
Cloudy
Fig. 5. Change of temperature within March.
Cloudy
Fig. 4 shows the weather conditions in Astana in January. It was plotted by using data obtained from weather diary [9]. Temperature grows from -16 to -8, with slight difference between daytime and evening temperatures. More than a half of the month was cloudy and snowy.
Cloudy Cloudy Cloudy, snow Cloudy, snow Cloudy, rain Cloudy Cloudy Cloudy Partly cloudy
According to Fig. 5, temperature in March grows from -10 to +5 at the end of the month. To sum up, primary weather factors that affect generation of current are cloudiness of the sky, and snowfall that covers PV panel. ISBN-978-81-932091-2-7
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Simulation As it said earlier, the power generated by PV modules depends on various conditions. A set of these conditions is called Standard Test Conditions (STC) and specified on Table III: TABLE III STANDARD TEST CONDITIONS B.
Parameter Irradiance at normal incidence Cell temperature Solar Spectrum
Symbol G
T AM
Value Unit 1000 W/m2
◦C -
25 1.5
The STC is related to the IEC 60904 standards, for PV modules following parameters are defined with 10% tolerance: open-circuit voltage Voc, short-circuit current Isc and maximum-point power (Pmpp). In reality, standard conditions occur seldom. Common I-V curves and P-V curves are tested for different cell temperatures and irradiances by Simulink. Simulation settings are taken from Pyramid 60-240Wp solar cells’ specifications which are installed on PV panels of Technopark. Table IV displays the solar cells’ characteristics. TABLE IV SPECIFICATIONS OF PYRAMID 60240WP PV MODULE ALFASOLAR Specification Short circuit current Open circuit voltage Maximum power current Maximum power voltage Maximum system voltage (IEC) Maximum power rating
Symbol Isc Voc Impp Vmpp -
Value 8.84A 37.37V 8.11A 30.19V 1000V
Wp
240W
Fig. 6. A structure of PV module model [10].
The Voltage input PV model is taken from [10], utilizing two inputs and two outputs in addition to PV panel specification settlement for initialization of module. Using this model, various cell characteristics are generated under changing irradiance with constant temperature and vice versa. The general form of the model is shown in Fig. 6. The module’s I-V curves at constant temperature and with different irradiances are depicted in Fig. 7. The solar irradiance was changed from 200W/m2 to 1000W/m2 whereas temperature remained at 25 ◦C. Clearly, when the irradiance increases the IV curve moved higher. Short circuit current ± open is also affected greatly. In contrast, circuit voltage experienced small changes in value throughout the irradiance variation. In terms of P-V curves, similar relation to current is observed for Maximum Power of PV cell under similar simulation (Fig. 8). Similarly, Fig. 9 displays I-V curves for different temperatures and 400W/m2 constant irradiance. In particular, temperature are chosen 0◦C and +40◦C. Also the P-V curves for these module temperatures at constant I=400W/m2 are illustrated in Fig. 12. According to Fig. 9 and 12, it is obvious that at lower temperature, the values of maximum power and open circuit voltage get higher. In sharp contrast to that, short circuit current decreased slightly as the cell temperature declined. Evaluation with Homer The economy is important function in designing solar power systems. The main elements in cost system are solar panels, inverters and construction expenditures. The economic aspects of PV system were analyzed by HOMER Pro software. Net present value (NPV), payback period and leveled cost of energy were assessed in this section. The electric load in this research was set to residential type with peak month of July. Numerical value of load was found by
C.
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considering each appliance in average house as shown in Table V. Daily and seasonal profiles for Astana are illustrated in Fig. 11. Electrical components for each solar power plant must be designed accurately.
Fig. 10. P-V curves for various irradiances at T=25◦C.
Fig. 7. I-V curves for various irradiances at T=25◦C.
Fig. 11. Load profiles
Fig. 8. P-V curves for various irradiances at T=25◦C.
§
Fig. 9. I-V curves for various temperature and constant I=400W/m2.
For safety reasons inverter size must be 2530% larger than total Watts of domestic appliances. In this case inverter size should be not less than 3.5kW. Therefore, for simulation purposes Leonics S-219Cp 5kW inverter with 48Vdc nominal voltage was chosen. Battery size (Ah) was calculated by the formula below: 7182W ∗ Autonomy = Size (Ah) = 880Ah 0.85 ∗ 0.6 ∗ Voltage Autonomy value was set to 3 days and voltage to 48Vdc, which must have identical value with inverter nominal voltage. For simulation CELLCUBE R FB 20-40 with nominal capacity of 833Ah and with 48Vdc nominal voltage was selected. The total cost of the system is illustrated in the Table VI. The PV panels cost include the installation, connections and panels cost itself. ISBN-978-81-932091-2-7
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Results are discussed in Table VII. TABLE V POWER CONSUMPTION OF ONE HOUSE Device
Power (W)
Lamp Fan Refrigerato r Oven TV Others Total
18 60 180
Hours used per day 4 2 24
Energy (Wh) 72 120 4320
1 5 6
2400 150 120 7182
2400 30 20 2708
DISCUSSION In data analysis section graphs that were obtained, show that although temperature influences the power generation in PV panels, its effect is cannot be compared to the effect of
IV.
TABLE VI TOTAL COST OF THE SYSTEM Unit
Size
Capital cost
O&M cost
PV panels
2.5kW
5000$
4.09$/year
Inverters
3.5kW
600$
0
Batteries
833Ah
500$
20$/year
cloudiness of the sky and snowfall. For instance, generation of current by 15 kW PV plant in January, fall from 11 A to less than 2 A, due to cloudy weather. Also, average generation of current in March is bigger than in January. This is the result of larger number of clear days. Fig. 12 illustrates I-V curves of Pyramid 60P for different irradiance at temperature 25◦C. Simulated curves, particularly in Fig. 7, revealed that they are consistent with characteristics of Pyramid 60P from datasheet. In economical part payback period was calculated by considering net present cost and savings of the entire project. Savings are total amount of money saved, because of autonomous energy generation, being independent from electrical grids of Astana with tariff of 0.067USD/kWh[11]. Economical result in terms of payback period is not attractive for investors or home owners. The reasons are aging of equipment and maintenance in Astana snowy conditions. TABLE VII ECONOMIC RESULTS System PV
Fig. 12. I-V curves of Pyramid 60P solar module (reference: Alfasolar datasheet). Temperature data obtained from Technopark was used in simulations for one home condition. Payback period and NPV were later obtained.
Savings($ ) 2977
NPV($) 43372
Payback
CoE
13.1 years
0.399
V. CONCLUSION Mathematical model of PV panel was studied and model of voltage input PV module was devised. According to the results, temperature decrease had a positive impact on output power of the system. It was shown that irradiance at cold temperatures resulted in an increase in output power. General I-V and PV curves were obtained using SIMULINK. Data was collected from Nazarbayev University Technopark. The data was processed and graphs of current change were developed for March and January. Economic aspects were simulated in HOMER software.
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studied. The developed model can be improved in order to observe effect of extreme environmental conditions to accurately assess the performance of PV panels in central Kazakhstan. In addition, data from Technopark for full year can be further analyzed to observe system Behaviour under other extreme weather conditions. REFERENCES 1. Rao, R. Pillai, M. Mani, and P. Ramamurthy, “Influence of dust de- position on photovoltaic panel performance,” Energy Procedia, vol. 54, pp. 690–700, 2014. 2. K. K. Khanum, A. Rao, N. Balaji, M. Mani, and P. C. Ramamurthy, “Performance evaluation for pv systems to synergistic influences of dust, wind and panel temperatures: Spectral insight,” in Photovoltaic Specialists Conference (PVSC), 2016 IEEE 43rd. IEEE, 2016, pp. 1715–1718. 3. Nanjannavar, P. Gandhi, and N. Patel, “Labview based pv cell characterization and mppt under varying temperature and irradiance conditions,” in Engineering (NUiCONE), 2013 Nirma University Inter- national Conference on. IEEE, 2013, pp. 1–6. 4. El-Shaer, M. Tadros, and M. Khalifa, “Effect of light intensity and temperature on crystalline silicon solar modules parameters,” Interna- tional Journal of Emerging Technology and Advanced Engineering, vol. 4, no. 8, pp. 311–326, 2014. 5. M. Hasan and S. Parida, “Temperature dependency of partial shading effect and corresponding electrical characterization of pv panel,” in Power & Energy Society General Meeting, 2015 IEEE. IEEE, 2015, pp. 1–3. 6. S. Mekhilef, R. Saidur, and M. Kamalisarvestani, “Effect of dust, humidity and air velocity on efficiency of photovoltaic cells,” Renewable and Sustainable Energy Reviews, vol. 16, no. 5, pp. 2920–2925, 2012. 7. W. Herrmann and N. Bogdanski, “Outdoor weathering of pv mod- ules—effects of various climates and comparison with accelerated laboratory testing,” in Photovoltaic Specialists
Conference (PVSC), 2011 37th IEEE. IEEE, 2011, pp. 002 305–002 311. 8. L. Micheli, M. Muller, and S. Kurtz, “Determining the effects of environment and atmospheric parameters on pv field performance,” in Photovoltaic Specialists Conference (PVSC), 2016 IEEE 43rd. IEEE, 2016, pp. 1724–1729. 9. https://www.gismeteo.kz/. 10. “Pv module. simulink models,” in ECEN 2060. Colorado University, 2008, pp. 1–11. 11. http://www.astanaenergosbyt.kz/tarif/.
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Design and Performance Evaluation of Improved Biogas Stove (IBS) by Preheating of Biogas V. K. Sukhwani, Nitesh Patidar, Abhishek Nagar Govt. Ujjain Engineering College, Indore Road, Ujjain (Madhya Pradesh) 456010, India. Corresponding Author: v_sukhwani@rediffmail.com, erniteshpatidar@gmail.com Abstract Biogas stoves generally do not fully utilize biogas due to high content of CO2 & moisture, which also causes flame lifting. These stoves take more time in cooking as compare to LPG stoves. Main objective of this work was to design an improved biogas stove for a small family base biogas plant user. A biogas stove was modified by installing an arrangement for preheating of raw biogas. Performance of Improved Biogas Stove (IBS) was evaluated on the basis of two factors i.e. (i) Variation in diameter of burner ports and (ii) Preheating of biogas. In experimental procedure, a fixed amount of water was heated in a specific utensil and temperature difference (ΔT) was measured after time ‘t’. This process was repeated with and without modifications in stove. The maximum performance improvement (43%) was evaluated with preheating of biogas on burner port of hole diameter 0.30cm. Key Words: Improved Design, IBS, DGS, Preheating. Ti NOMENCLATURE ΔT ΔT
Burner Port
ɸ
Diameter of burner port hole Burner Port
BP
1.
LP G IBS T
Liquefied Petroleum Gas Improved Biogas Stove Temperature (00C=273.2K)
Introduction Biogas is a renewable energy resource, which is easily available and utilization of biogas is helpful to decrease global warming effect. In a biogas stove combustion of Methane (CH4) takes place and it is converted into CO2 and H2O. Methane is 21 times effective than carbon Dioxide (CO2) in increasing global warming. Designs of general biogas stoves have some drawbacks like Low heating rate, Time consumption more than LPG, Loss of heat, Flame-lift, Content of CO2 and water vapor etc. Due to long heating time in biogas stove, variable production rate of digester and other problems of stove demotivates biogas users. Water vapors present in biogas has a small but noticeable impact on flame temperature, Inflammability limits, lower heating value and air-fuel ratio of biogas. In India, a patent was
1
ΔT ’
Initial Temperature Temperature difference without preheating Difference in ΔT or (ΔT2ΔT1)
Tf ΔT2
Final Temperature Temperature difference with preheating
granted to Ucchrangraj Navalshannkar Dhehar [2] on 17th April, 1969 for his initial design of a biogas stove. A report on “Popular Summary of the Test Reports on Biogas Stoves and Lamps” was summarized by Dr. K. C. Khandelwal and Dr. Vibha K. Gupta [7]. In this research work, the specifications, testing methodology for stoves and lamps, suited to variable and high gas pressures of fixed dome plants has been suggested. 1.1 Objectives of work: Two main objectives of this work were as follows (a) To design an Improved Biogas Stove with an arrangement of preheating of biogas to increase its efficiency. (b) To evaluate performance of Improved Biogas Stove on three burner ports of different diameter of holes by measuring temperature ISBN-978-81-932091-2-7
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difference of two cases i.e. with and without preheating of biogas.
2.
Biogas plant Experiments were carried out at a family based biogas digester, which was installed in year 1996 at Mr. B.K. Patidar’s house located at Chamble Chauraha, Bhanpura, Mandsaur, Madhya Pradesh-458775, India. Contact: +919424097177. General information of biogas digester is followingType of digester: Floating doam type. Material: Dunk from two buffalos only. Quantity of dunk: 20 kg per day. Quantity of water added: 25 kg per 20 kg of dunk Maximum Average temperature of surrounding: In summer= 45 0C, In winter= 250C, In Rainy= 300C Composition: Methane=67%, CO2=32%, other=1-2% (Measured by Syringe Method)
3.
Design and manufacturing of improved biogas stove 4. IBS was manufactured in welding shop on the basis of Engineering Design prepared by project team (Figure-1). The main parts of Improved Biogas Stove and key features are as follows. Upper Frame: It has been made of cylindrical rods, in square shape of 30x30 cm2, Diameter of rod= 1.2cm, Weight= 1.1kg. Prongs: 4 cantilever type Utensil stand arms have been fitted at the midpoints of all 4 frame rods. Length=8cm, Width=2cm, Thickness=0.4cm, Weight=0.3kg. Stand legs: Two strips have been joined perpendicularly to make a stand. Each strip Height=12cm cm, Width=2 cm, Thickness=0.2cm, No. of legs= 4, Total weight= 0.6 kg, Total weight of frame = 2kg. Burner unit: It consists of burner manifold, mixing tube and burner ports. In mixing tube, the mixture of gas and air is prepared.
Key feature: Burner unit is adjustable by a nut-bolt arrangement at the opposite side of gas entry. It can be moved up and down to set up a suitable distance between utensil’s bottom and flame to confirm the full utilization of heat even at low supply of gas. Nuts: Diameter=0.4cm, Type: Hexagonal, Bolts: Nos. 2, Diameter= 0.4cm, Height=4cm Manifold: (Fig. 3.3) Inner diameter=3.4 cm Outer diameter=7.5 cm Thickness=0.25cm, Height= 1cm to 5cm Key feature: At the end of mixing tube the inner part of manifold is in curved shape; it reduces the velocity of the air-gas mixture. Slow entry of charge reduces the chances of Flame Lifting and gives better flame stabilization. Mixing tube: Length= 10.5cm, 2 holes of size 1.5x2.5 cm2 at the beginning of tube for the entry of air, Inner diameter=1.9cm, Outer diameter=2.4cm(Fig 3.2) Burner Ports: The total area of the burner port is limited by the need to prevent flame lift. Requirements of a good burner port are: Port No.1: weight= 140 gm, Diameter of hole = 0.18cm Port No. 2: weight= 120 gm, Diameter of hole= 0.30cm Port No. 3; weight= 150 gm, Diameter of hole= 0.50cm Supply Tube: It is a single valve consisting tube of length 30cm. At one end, preheating tube has been connected and other end remains closed. At midpoint, it has a hole of 1 cm diameter to attach a valve. Key feature: This tube can also be used to connect an LPG or biogas supply tube. Valve: A simple LPG stove valve was used. A switch was attached to turn the valve (ATC Gold). Type: LPG Valve. Valve consists of - Excluded brass forging, 12mm Taper plug, 34mm Spindle Brass Screw & Steel Spring. Key features: It is easily available in market and can also be used for both of the gases i.e. biogas and LPG. Pre-Heating Tube: Length=87cm, Inner diameter=0.3cm, Helical ring: No. ISBN-978-81-932091-2-7
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of turns=2, Height of turns= 1-2 cm, Length of turns=55 cm Key features: It helps in utilization of radiant heat from burner ports to pre-heat biogas. Moisture content in biogas is heated by this method, which leads to convert it into low pressure steam and hence heat efficiency is increased. Thus, the chances of corrosion of valve, supply tube and mixing tube gets minimized. Preheating also minimize ignition temperature of biogas.
5.
Performance evaluation of improved biogas stove IBS was mainly designed for cooking purpose, so the performance measurement was carried out by heating a fixed amount of water in a specific utensil of stainless steel and measuring temperature difference after time ‘t’ on a constant discharge flow and pressure of biogas. This process has been repeated before and after a modification in stove. 4.1 Required items for experiments: a) Stainless Steel Jar: Cylindrical jar of Height=15cm, Diameter=12.5cm, Thickness=0.03cm b) Thermometer: Mercury thermometer of maximum capacity of 110oC (Manufactured by Vertex Deluxe). c) Electronic watch. 4.2 Experimental Set Up: Temperature of biogas was measured before entering preheating tube. After preheating of biogas, temperature was measured. Flow of preheated 5.1 Comparison of performance of the Improved Biogas Stove on BP-1, BP-2 and BP-3 without any modification (Figure-2 & 3 and Table-1): This experiment was conducted on 29/04/2014 at 09:00 PM and conditions were as follows-
biogas is controlled by valve. A jar of steel filled up with water was kept on stove. Initial temperature (Ti) of water was measured by thermometer. After time‘t’, final temperature (Tf) of water was measured (Figure-1). 4.3 Experimental Procedure for Performance Evaluation of Improved biogas Stove (IBS): Preheated biogas was used to evaluate the performance of IBS by heating water. Different cases and measurements have been mentioned in section 4.4 and also shown in tables 1-5. These steps were followed to perform evaluation experiments. a) A steel jar was filled with 1 liter of water and the initial temperature of water i.e. Ti was measured by thermometer. b) The temperature, pressure and flow of biogas and surrounding temperature were measured. c) Water was heated for time ‘t’ i.e. 1min, 3min, 5 min, 10min etc. d) Final temperature of water after heating i.e. Tf was measured. e) Steps 2 to 5 were repeated with and without modifications, so that observations could be compared. Observations and readings have been shown in table 1 to 5.
6.
Experiments performed on improved biogas stove in different cases Experiments were conducted for four different cases. Observations have been mentioned in Section 5.1 to 5.4. Surrounding temperature: 320C Temperature of untreated biogas: 310C Pressure of biogas: 1 atm
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5.2 Comparison of performance of Improved Biogas Stove (IBS) with and without preheating of biogas on BP-1 Surrounding temperature: 31 0C Temperature of biogas: 32 0C Temperature of biogas: 35 0C Pressure of biogas: 1 atm Flow of biogas through supply tube: 4Ltr/min
(Figure-2 & 3 and Table-2): This experiment was conducted on 28/04/2014 at 8:00 PM and conditions were as follows -
5.3 Comparison of performance of IBS with and without preheating of biogas on BP- 2 : 5.4 (Figure-2 & 3 and Table-3): This experiment was conducted on 28/04/2014 at 9:00 PM and conditions were as follows Surrounding temperature: 31 0C Temperature of biogas: 32 0C Temperature of biogas: 35 0C Pressure of biogas: 1 atm Flow of biogas through supply tube: 4Ltr/min
5.5 Comparison of performance of IBS with and without preheating of biogas on BP-3 (Figure-2 & 3 and Table-4): This experiment was conducted on 29/04/2014 at 8:00PM. Surrounding temperature: 31 0C
6.
achieved on performance evaluation of Improved Biogas Stove in different cases as mentioned in Section 5.
Results and discussion Section 6.1 to 6.3 depicts graphical representation and observations of results
Temperature of biogas: 32 0C Temperature of biogas: 35 0C Pressure of biogas: 1 atm Flow of biogas through supply tube: 4Ltr/min
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6.1 Performance evaluation of IBS with variation in diameter of burner ports without preheating of biogas: Also refer Section-5.1, Table-5 and Figure-4.
Biogas Stove. A better flame stability with less sound and less flame lifting were observed in BP-2. Graphical representation in Figure-5 and Figure-7 indicate that preheating of biogas on BP-1 and BP-3 should not be recommended for household use. Figure-6 shows that BP-2 can be recommended for household use of IBS with preheating of biogas and also, preheating of biogas, less flame-lifting and limited noise of combustion were observed. The results also indicate that there is always an improvement in performance of IBS due to preheating only, but there is not a directly proportional relation between the diameter of burner port and the performance improvement of IBS with preheating only. (Figure-8)
As shown in Figure-5, Observations of graph depicts that there is no directly proportional relation between the diameter of burner port and the performance improvement of IBS in case of “without any modification”. BP-2 (ϕ=0.3cm) can be suggested for household use without any modification in ordinary biogas stove or without preheating in Improved
6.2 Performance evaluation of IBS with preheating of biogas: Also refer Section 5.2 to 5.4, Table-6 and Figure-5, 6 & 7.
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8.3 Heat efficiency of utensil may differ per type of material. 5ml syringe
7. Precautions during experiments for performance evaluation of improved biogas stove 7.1 Temperature and pressure of surroundings were almost constant in each case of experiments and observations. 7.2 Quantity and initial temperature of water, steel jar and heat up time were almost same for two cases which are compared to measure the effect of each specific modification. 7.3 Flow rate, temperature and pressure of supplied biogas were maintained almost constant in each of two cases, which were compared to measure the effect under specific conditions and type of modification. 7.4 Gap between the bottom of steel jar and the burner port was fixed (in experiments it was approx. 3.5cm). 8. Limitations of experimental procedure of performance evaluation of IBS During the experiments, reasonably good precautions were adopted, but limitations are mentioned below 8.1 Biogas production rate of digester is not constant throughout the day and the year as well. 8.2 Biogas production rate and quantity of CO2 and CH4 in biogas depends on the type of raw material used in digester.
9.
CONCLUSION: Following major points can be concluded from this research work on Design and Performance Evaluation of Improved Biogas Stove (IBS).
9.1 Burner port of larger diameter (0.50cm in our case) is recommended for the better performance of Improved Biogas Stove without preheating or without any modification in an ordinary biogas stove. 9.2 Burner port of medium range diameter (0.3 cm in our case) is recommended for better performance of Improved Biogas Stove with preheating of biogas. It also provides better flame stability and sound control of gas combustion. 9.3 Total Cost of IBS was ₹614 and fabrication time was 1 hour. Time and cost can be reduced by manufacturing this Improved Biogas Stove on a large scale. 9.4 Future recommendation for the work is evaluation of Improved Biogas Stove with preheating of biogas can be carried out with some other burner ports of different diameter of hole and content of CO2, H2S and moisture can be reduced by further modifications in this biogas stove. References 1. National Biomass Cook stoves programme (NBCS) of Government of India, Ministry of New and Renewable Energy. Website: http://www.mnre.gov.in/schemes/dece ntralized-systems/national-biomassISBN-978-81-932091-2-7
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2.
3.
4.
5. 6.
cookstoves-initiative/, (accessed 15 Apr 2014). Uchhrangraj Navalshankar Dhebar (1969), Chairman, Khadi and Village Industries Commission, Bombay, India, “Burners Particularly for Biogas and Lamps using such Burners”, Specification No. ***688, Application accepted on 17th April, 1969. An Indian Patent granted by The Patent Office, Calcutta, India. Dr. D. Fulford (1988), “A Handbook on Running a Biogas Programme”, ©Intermediate Technology Publications, 103-105 Southampton Row, London WC1B 4HH, UK, 60-67 Dr. D. Fulford (1996), “A short Course on Biogas Stove Design”, Kingdom Bioenergy Limited, University of Reading, U.K. WORGAS®, Energy Transformation Technology, “Gas Burner Technology & Gas Burner Design for Application” J.N. Shrestha (2004), “A Final Report on Efficiency Measurement of Biogas Stoves”, submitted to Biogas Support Partnership Nepal submitted by Center for Energy Studies, Institute of
Engineering Tribhuvan University, Pulchowok, Lalitpur. 7. Dr. K. C. Khandelwal and Dr. Vibha K. Gupta (2009), “Test Reports on Biogas Stoves and Lamps prepared by testing institutes in China, India and the Netherlands”, SNV Netherlands Development Organization, The Hague, The Netherlands. 8. BIS.2002. IS 8749:2002 (Reaffirmed 2008) Biogas stove-specification (Second Revision).ICS 97.040.20, BIS 2002. Bureau of Indian Standards, Manak Bhavan, 9 Bahadur Shah JafarMarg, New Delhi 110002, India. 9. AutoCAD 2014: Student Version, An Autodesk Product, website: www.autodesk.com, (accessed 5 Apr 2014). 10. Wikipedia, the Free Encyclopedia. Website: www.en.wikipedia.org, (accessed 15 Apr 2014). 11. The University of Adelaide, South Australia 5005, Australia, 12. Tel: +61883134455 and Website: www.adelaide.edu.au/biogas/, (accessed 20 Apr 2014).
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Empowering Rural Women through Renewable Energy Technologies Diksha Srivastava1, Deepak Sharma2 and Kapil K Samar3 1,2
Department of Renewable Energy Engineering, Udaipur 3 Biogas Development and Training Centre, Udaipur Email: dkshme@gmail.com; Phone No.: +91-7597130060
Abstract There is no denying the fact that women in India have made a considerable progress in decades of Independence, but they still have to struggle against many issues for leading a sustainable life. This is mainly because they are not only the producers but also managers of food, water, fuel and fodder, etc. Women empowerment is the most critical issue of the present time. If women, particularly the rural and tribal women are encouraged and educated about the appropriate and judicious use of energy resources, problems such as food security, energy crises and environmental degradation could be minimized. The focus of this research paper therefore, is on the women empowerment through the adaptation of various renewable energy technologies developed in the recent times to lead an easy, healthy and independent life. In India, about 40% of the total energy consumed is in rural areas, either in the form of wood, agrowaste or cattle dung used for cooking or lightening. These domestic activities are mainly considered as women’s task in Indian context. By educating and making women adopt Renewable Energy Technologies, they can be spared from the problems such as fuel wood collection, walking kilometers in search of water; preparing cattle dung cakes, etc. The time which she devotes in all such works can be utilized to reduce drudgery and in gaining occupations; empowering women not only economically but also socially. Keywords: Women empowerment, Renewable energy technologies, Sustainable life, energy security
1.
Introduction
The most famous saying said by the Pandit Jawaharlal Nehru is “To awaken the people, it is the women who must be awakened. Once she is on the move, the family moves, the village moves, the nation moves”. In India, to empower the women, she should be made strong not only physically but also mentally and socially. For this, the education should be started at home from childhood, because the upliftment of women needs healthy family; resulting in the holistic development of the nation. Since Independence, women in India have made a considerable progress, but they still have to struggle against many issues for leading a sustainable life such as struggle against potable water, for which they have to walk miles;
struggle against fuel wood, for which they have been denied education and have to go to forest or lonely shrubby places; etc. Energy availability, both in adequate quantity and quality, is a pre-requisite to sustain targeted economic growth and the desired levels and speed of social development. There are number of unit operations in domestic, agriculture, transportation and industrial sector consuming bulk of conventional energy sources. In India, about 40% of the total energy consumed is in rural areas, either in the form of wood, agrowaste or cattle dung. At domestic level the energy is consumed for cooking, lightning, drying & dehydration and other thermal heat applications where renewable energy sources can easily be integrated for energy conservation. ISBN-978-81-932091-2-7
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There is significant potential for application of Renewable Energy Technologies in Rural India. If women, particularly the rural and tribal women are encouraged and educated about the appropriate and judicious use of energy resources, problems such as food security, energy crises and environmental degradation could be minimized. Women are not only the producers but also managers of food, water, fuel and fodder, etc. By educating and making women adapt these technologies, drudgery will be reduced and women will be gaining occupations; empowering them not only economically but also socially. Few of these Renewable Energy Technologies, available commercially, which will help women in their day to day activities are:
2.
Solar Energy
Solar energy is a clean and unlimited source of energy. Capturing the sun's energy for light, heat, hot water and electricity can be a convenient way to save money, increase selfreliance, and reduce pollution. Solar technologies can be used to produce electrical or thermal energy. It is estimated that solar energy equivalent to over 15,000 times the world's annual commercial energy consumption reaches the earth every year. India receives solar energy in the region of 5 to 7 kWh/m2 for 300 to 330 days in a year. This energy is sufficient to set up 20 MW solar power plants per square kilometre land area. The solar thermal energy for cooling, heating, steaming and drying and solar PV for power generation can economically provide energy where the distance is too great to justify new system. Solar electric systems are used to provide electricity for lighting, battery charging, small motors, water pumping, and electric fences etc.
2.1 Solar Cookers Box type solar cookers are capable of cooking different types of food including rice, vegetables, chicken, fish, and for steaming, roasting, boiling etc. It works as an airtight box with double glass covers. A reflector is placed over it for boosting the solar radiation and thus its temperature increases. Because of its simplicity and ease of handling, the box type solar cooker has found wider acceptance especially in rural areas. Whereas, Dish or Parabolic solar cookers, have an aperture diameter of 1.4 m and focal length 0.28 m. The reflecting material used for their fabrication is anodized aluminium sheet which has a reflectivity of over 75 per cent. The tracking of the cooker is manual and thus has to be adjusted after every 15 to 20 minutes during cooking time. It has a delivering power of about 0.6 kW which can boil 2 to 3 L of water in half an hour.
Solar Box Cooker Concentrated Cooker
Solar
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day. IREDA provides the loan to the commercial agencies for the promotion of installation of the solar hot water systems. Besides this, many state governments have been giving special subsidies to domestic users of the solar water heaters of the capacity of 100 litres per day capacity.
2.2 Solar Water Heating System These systems are equipped with flat plate collectors (FPC) with built in channels or riser tubes attached (ETC) to the absorber sheet. With a black paint coated on the absorber plate, the water can be heated up to a temperature of 60° to 90°C, while in selectively coated system the temperature of water can be raised from 85° to 100° C. Presently, the solar water heating systems are used for domestic, commercial and industrial applications.
2.3 Solar Dryers
FPC type Solar Water Heater ETC type Solar Water Heater A temperature of 60° C is sufficient for domestic use and as such black paint coated absorbers are normally used in such domestic solar water heating systems. Solar water heating systems have capacity ranging from 100 litres per day to over 200,000 litters per
The solar drying systems have many applications; both at domestic and industrial level. The various designs of direct as well indirect type solar dryers for drying vegetables, fruits, grains, fish, timber, chemicals and other industrial products etc. are available. .
Solar tunnel dryer for industrial purpose Solar domestic dryers These dryers not only save energy but also save lot of time, occupy less area, improve quality of ISBN-978-81-932091-2-7
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the dried product, make the process more efficient and protects environment also. Solar dryers circumvent some of the major disadvantages of classical drying. Solar drying can be used for the entire drying process or for supplementing artificial drying systems, thus reducing the total amount of fuel energy required. Solar dryer is a very useful device for: Dairy industries for production of milk powder, casein etc. Seasoning of wood and timber. Textile industries for drying of textile materials. Agriculture crop drying Food processing industries for dehydration of fruits, potatoes, onions and other vegetables
2.4 Solar Lantern and Street Lighting System A typical solar lantern consists of a small photovoltaic module, a light source, a high frequency inverter/ballast, battery, charge controller and appropriate unit. During the day hours, the module facing south is placed in the sun and it converts the solar radiation into electricity and charges the battery which is connected to the lantern through a cable. In the evening, the lantern with the charged battery is disconnected from the module and is available for indoor or outdoor use. Whereas; the solar PV based street lighting system has a pole, a battery enclosure, a battery, a LED or CFL based light and Photo voltaic module. During the day hours, the module facing south is charges the battery. In the evening, when voltage through module gets down, the controller automatically starts the light for lighting the street or roads. In the morning, when module starts to produce power, the controller automatically power off the light.
Solar Lantern and Street Lighting System
3.
Unnat Chulahs
In rural households, food is generally cooked on clay stoves called ‘Chulhas’. Chulhas use biomass in the form of fuel wood as fuel. A family of 5 to 6 persons requires about 8 kg fuel woods every day. Surveys show that, on an average, the domestic fuel consists mainly of agricultural residues and cattle dung, supplemented by fuel wood to the extent of about 40%. However, these traditional chulhas are very wasteful as they use only 10% of the total heating potential of the fuel burnt in them. A more serious disadvantage of the traditional chulhas is that they produce a lot of smoke, soot and unburnt volatile organic matter, which not only blacken the pots and the walls of the kitchen, but also lead to Indoor Air Pollution (IAP). It adversely affects the health of the rural ISBN-978-81-932091-2-7
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householders by slow health degradation and setting the onset of killer respiratory diseases. In present, two models of Unnat Chulhas namely, Udairaj and Chetak have been developed by Department of Renewable Energy Engineering, CTAE, Udaipur. Chetak is a onepot model whereas Udairaj is two- pot model of Unnat Chulhas. These models can also be called as modified traditional chulhas, in which energy loss due to radiation and convection are minimized; resulting in saving of fuels. Like traditional chulhas; these Unnat Chulhas are also made from bricks and cement or clay. Smoke can be exhausted out of the house with the use of an outlet. Due to this, the harmful effects due to smoke are greatly reduced. Their life span is estimated to be of approximately 5 years. Environmental changes such as rainfall, etc. didn’t exert much change on their structure. The efficiency of Unnat Chulhas was also measured in actual operation which indicates about 22 percent thermal efficiency. It is also observed that on an average 950 kg of fuel wood can be saved by using one Unnat Chulhas in a year.
Udairaj Unnat Chulha
4.
Biogas Technology
The main energy source for generating Biogas is organic matter. Generally, biogas is prepared by the anaerobic digestion of cattle dung and water mixed in equal quantities. Biogas comprises of
60-65 percent methane (CH4), 35- 40 percent carbon dioxide (CO2), 0.5-1.0 per cent hydrogen sulphide (H2S) and traces of water vapours. It is almost 20 percent lighter than air. Biogas cannot be converted into liquid like liquefied petroleum gas (LPG) under normal temperature and pressure. The slurry coming from digester is rich in nitrogen which is an essential nutrient for plant growth. Biogas is an easy and healthy cooking fuel since methane emissions from untreated cattle dung and biomass wastes can also be avoided. Since there is no pollution from biogas plants, these are one of the most potent tools for mitigating climatic change and being earth saviors.
Biogas Lamp being used Biogas Plant used for domestic purpose The energy liberated by Biogas is not only used for cooking but can also be used for lightning lamps and for power generation. Biogas lamps ISBN-978-81-932091-2-7
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are commercially available for lightning purpose. Power could be generated using biogas, using Biogas Genset. Subsidy is also provided by Government of India for setting up biogas plant for domestic purposes.
Biogas being used for cooking Properties of Biogas which make it an excellent fuel are: Biogas is a non-toxic, colourless and flammable gas. It has an ignition temperature of 650 – 750 °C. Its density is 1.214 kg/ m3 About 60 percent methane and 40 percent CO2 content Calorific value is 20 MJ/m3 (4700 kcal). Almost 20 percent lighter than air It liquefies at a pressure of about 47.4 kg/cm2 at a critical temperature of - 82.1°C. Purified biogas (bio-methane) has a higher calorific value in comparison to raw biogas. There are two designs of biogas plant popular in India: (a) Floating Gas holder type. (b) Fixed dome type
(a) In floating drum type design, the digester is an underground tank constructed in brick masonry, stone masonry, RCC or ferrocement. It has an inverted metallic drum which acts as gas holder. The gas produced in digester is collected in gas holder at a constant pressure depends on the weight of gas holder. The merits of this design are: Gas is supplied at constant pressure It has a provision for breaking scum. Any local mason can construct the plant. At high water table area, horizontal plant can be constructed. Different models comes in category are KVIC vertical and horizontal, Pragati Model, Ganesh Model and Ferrocement digester. (b) The fixed dome type biogas plant is a dome shaped underground construction. The masonry gas holder is an integral part of the digester called dome. The gas produced in the digester is collected in dome at variable pressure by displacement of slurry to inlet and outlet. The merits of these designs are: The construction is made entirely of bricks and cement which are locally available. Steel gas holder is not required. . As there is no moving part, the maintenance cost is minimised. Less effected by low temperature. The space above the plant is usable as the plant is under ground. Other materials along with dung slurry can be charged. The scope of biogas has been enlarged by coupling all type of organic waste along with dung recycling including fruits & vegetables ISBN-978-81-932091-2-7
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waste. Presently biogas is not only recognized as gas production from dung recycling but also it is also known as all organic waste recycling for resource recovery system in terms of biogas & enriched manure. In fact there is no waste; all waste can be used as source for wealth. In India there is good potential of waste material, which can easily be converted in biogas.
3
Water Solar water heating, Heating biogas, Unnat Chulhas 4 Drying Solar dryers 5 Electricity Solar photovoltaic production system, biogas genset To conclude, introducing women to the renewable energy technologies can mitigate drudgery, reduce environmental damage, support meeting of their basic energy needs and foster productive activities for their economic and social upliftment.
References:
Mode of Operation of Biogas Plants and their Uses
5.
Summary
In contrast to conventional energy sources, the potential supply from renewable is essentially infinite and largely free of external costs. Some Renewable Energy Technologies are already competitive with conventional energy sources, for example biomass or biogas applications. Renewable energy provides greater flexibility. Various daily household applications that can be used by women in their day to day activities are as mention underS.N. Application Renewable Energy Technology 1 Cooking Biogas, Solar Cooker, Unnat Chulhas 2 Lighting Solar Home lighting, Solar lantern, Solar Street Light, Biogas Lamps
1. Bansal, N.K., Hake, J., 2000. Energy needs and supply options for developing countries. Proceedings of the World Engineer's Convocation (Energy section), Hanover, pp. 6596. 2. Bernow, S., Dougherty, W., Duckworth, M., Brower, M., 1998. An integrated approach to climate change policy in the US electric power sector. Journal of Energy Policy 26 (5), 375-393. 3. Grover P D (2004) Characterization of biomass for energy generation. Biomass Management for energy purposes – issues and strategies, Proceedings of the national seminar, SPRERI, Anand, Gujarat: 134-174. 4. Hall D O, Rosillo-Calle F, Woods J (1991). Biomass, its importance in balancing CO2 budgets. In: Grassi G, Collina A, Zibetta H, editors. Biomass for energy, industry and environment, 6th E.C. Conference Elsevier Science, London, : 89-96 5. https://www.iaspaper.net/womenempowerment-in-india/
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AN EXPERT SYSTEM FOR THE ESTIMATION OF DIRECT SOLAR RADIATION IN INDIAN REGION 1
R. K. Tomar, 2N. D.Kaushik
Department of Civil Engineering, Amity University Uttar Pradesh, Noida -201313, India. 1
Centre for Energy Studies, Indian Institute of Technology, Hauz Khas, New Delhi-110016, India.
E-mail address: rktomar67@gmail.com
Abstract In this paper an expert system is developed for the estimation of direct solar radiation in Indian region. The basic premise is to have a software tool that shall provide comprehensive support to general users working in assorted fields like climatology, solar energy utilization and environmental impact assessment. The approach involves artificial neural network model and is envisioned to provide general users the power of an expert. It can also be adapted easily to change of climatic conditions. Keywords: Solar radiation, Expert system, Artificial Neural Network. 1. Introduction consideration of parameters related to climate Radiant energy from sun is vital for life on our and weather phenomena. In recent years, the planet. It determines the surface temperature of models of estimation of solar radiation using earth as well as supplies all energy for natural fuzzy random variables have been developed processes both on earth’s surface and its (Gautam & Kaushika 2002) which has defined atmosphere. The solar radiation estimation is the Clearness Index(CI) of extra-terrestrial required in many disciplines such as radiation that reaches the earth’s surface when Climatology, Solar energy utilization & the sky above the location of interest is Environmental impact assessment. All the users obscured by the cloud cover or otherwise. More of solar resource do not have expertise and/or recently, Tomar et al. 2012, have used the ideas easy access to the solar resource data of the of neural nets, parallel distributed processing location of their requirement. Furthermore, the and connectionist network to determine solar radiation is generally variable and Clearness Index. This approach is often termed enormously inconsistent and in practice the as Artificial Neural Network (ANN) modeling. models of estimation of solar radiation are often These models owing to their rigor are useful for used. the expert system approach. In this paper we have made an effort to widen 3. The Algorithm the usability of the models for a larger crossSolar energy is in the form of radiant energy section of the users. This approach may be and the radiation has nearly fixed intensity referred to as the expert system approach. The outside the earth’s atmosphere. It is referred to expert system is a software tool that is as Extra-terrestrial radiation. It is characterized envisioned to provide general user the power of by the solar constant Isc. It is defined as the an expert. energy received from the sun per unit area 2. Model Approach placed perpendicular to the sun rays outside the Several models have been developed for the earth’s atmosphere at sun-earth mean distance. estimation of solar radiation at different Its value in the present software is taken to be geographical and meteorological conditions 1364 W/m2 (Mishra et al. 2008 and Tomar et al. (Reddy 1971; Hottel 1976; Sabbagh et al. 1977; 2012). Owing to the variation in the sun-earth Barbaro et al.1978; Goh 1979; El-Nashar 1981; distance, Isc varies during the year round cycle. Ogeman et al. 1984; Supi & Van Kappel 1998: The value of Isc on the nth day of the year (n = Mishra et al. 2008,). These models lack detailed 1 for Jan 1), Io may be calculated as follows ISBN-978-81-932091-2-7
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360n Io=Isc 1+0.034cos 365.25
The solar radiation is received at earth’s surface after being subjected to the mechanisms of attenuation, reflection and scattering in the atmosphere which in turn are the functions of solar zenith angle or the solar incident angle on the horizontal plane, the declination angle and the hour angle(time of the day). The radiation received without change in the direction is referred to as beam radiation or direct solar radiation. As a first approximation, the solar beam radiation intensity can be obtained from a simple clear day model by Hottel 1976. The model is based on atmospheric transmittance calculation using the 1962 US standard atmosphere and has been subsequently corrected for climate conditions. So we have:
al. 2012 we have investigated the variation of Clearness Index as a function of latitude, longitude, time of the day and day of the year. The mean monthly variation of Clearness Index as a function of latitude is shown in fig. 1. So the grey day radiation may be determined by multiplying the solar radiation values with the Clearness index defined as follows:
Clearness Index (CI) =
Sbnm Sbnc
Sbnc=Io ao+a1e-ksecθz
Fig. 1: Clearness Index graph where the parameters ao, a1 and k are the functions of height above sea level in kilometers and the climate of the location (Duffie & Beckman 1991). The climate corrected calculated clear day values (Sbnc) are often higher than the observations (Sbnm). The deviations exhibit variability with time of the day, day of the year and meteorological parameters such as rainfall, relative humidity, mean duration of sunshine. A parameter characteristic of the weather phenomenon was referred to as Clearness index (Tomar et al. 2012). Following the neural network analysis procedure of Mishra et al. 2008 and Tomar et
Fig. 2: Flowchart of the program execution 4. Computational Flowchart From the above algorithm it is clear that the solar radiation value at a particular location is the function of the height above sea level in kilometers, the latitude of the location, day of the year, time of the day and the Clearness index. Using these input parameters, computational process is illustrated in the flowchart depicted in Fig: 2. 5. Structure of the Expert System The graphical user interface (GUI) of the expert system is illustrated in Fig. 3. Upon providing the values in the input boxes, the press of calculate button shows the results in the output box which can either be printed or saved in a text file.
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Fig. 3: GUI of Expert System 6. Validation of results With a view to examine the compatibility of the predictions of the expert system approach, we have investigated the RMSE (%) values for the stations spread all over India. The RMSE (%) ranges for most of the stations used in the analysis were in the range of 13.36 - 24.64 for direct solar radiation. The range is of the right order of magnitude in view of the prediction errors reported by earlier researchers, for example 22.73% reported by NASA SSE data sets. However, it was noticed that the RMSE (%) values of costal locations are relatively higher owing to intensive monsoon activities and their effect on observed data. 7. Summary and conclusion The estimation and prediction of direct solar radiation is useful for a wide spectrum of users such as energy planner, engineers, architects, solar scientists and researchers. In this paper an artificial neural network based computational models for the estimation and prediction of solar radiation in Indian zone is presented. The analysis is based on the data of the stations cover by far the widest range of latitudes (8.480N to 34.080N) and longitudes (72.180E to 92.720E) spread over the entire Indian continent. The contour maps of atmospheric clearness index as a function of latitude, month of the year and time of the day are drawn. Finally the methodology for the prediction of
direct solar radiation at an arbitrary location using these maps is developed. The computational scheme is embedded in a graphical user interface designed to be usable, as an easy to understand expert system, by a wider cross section of investigators. The computational results obtained from GUI exhibit good compatibility with earlier models and recent measurements carried out at arbitrary locations in Indian region. References 1. Barbaro S., Coolino S., Leone C., & Sinagra E. (1978). Global solar radiation in Italy. Solar Energy, 200, 431. 2. Duffie J. A. & Beckman W. A. (1991). Solar engineering of thermal processes. (New York: John Willey & Sons). 3. El-Nashar A. M. (1981). Solar radiation characteristics in Abu Dhabi. Solar Energy, 47(1), 49. 4. Gautam N. K. & Kaushika N. D. (2002). A Model for the Estimation of Global Solar Radiation Using Fuzzy Random Variable. Journal of Applied Meteorology, Vol. 41 No. 12, 1267-1276. 5. Goh T. N. (1979). Statistical study of solar radiation in formation in an equatorial region (Singapore). Solar Energy, 22, 105. 6. Hottel H. C. (1976). A sample model for estimating the transmittance of direct solar radiation through clear atmosphere. Solar Energy, 18, 129. 7. Internet World Stats – http://www.internetworldstats.com/stats.htm (last accessed on 19th May 2010) 8. Kaushika N.D., Tomar R.K. and Kaushik S.C., 2014. Artificial neural network model based on Interrelationship of direct, diffuse and global solar radiations. Solar Energy 103,327-342. 9. Mishra Anuradha, Kaushika N. D., Zhang Guoqiang, & Zhou Jin (2008). Artificial neural network model for the estimation of direct solar radiation in the Indian zone. International Journal of Sustainable Energy, 27:3, 95-103. 10. NASA SSE web portal <http://eosweb.larc.nasa.gov/sse/>. ISBN-978-81-932091-2-7
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11. Ogeman H., Ecevit A., & Tasdemiroglu E. (1984). A new method for estimating solar radiation from bright sunshine data. Solar Energy, 71, 307-319. 12. Reddy S. J. (1971). An empirical method for the estimation of the total solar radiation. Solar Energy, 14, 289. 13. Sabbagh J. A., Sayigh A. A. M., & ElSalam E. M. A. (1977). Estimation of the
total solar radiation from meteorological data. Solar Energy, 19, 307. 14. Supi I. & Van Kappel R. R. (1998). A simple method to estimate global radiation. Solar Energy, 63, 147. 15. Tomar, R.K., Kaushika, N.D., Kaushik, S.C., 2012. Artificial neural network based computational model for the prediction of direct solar radiation in Indian zone. J. Renew. Sustain. Energy 4, 063146.
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Parametric study of Pump as Turbine-2: Variation of Diameter of Impeller
Doshi A. V.1; Bade M. H, Sahu Rohit2 Mechanical Engineering Department, Sardar Vallabhbhai National Institute of Technology, Ichchhanath, Surat-395007, Gujarat, India 2 Alpha College of Engineering and Technology, Beside Lincon Polymers, At Khatraj, Kalol Taluk, Gandhinagar, Gujarat 382721 1
Abstract Among renewable energy sources, for isolated power production, pump as turbine (PAT) are potential energy source where energy is required mainly for lighting during night hours and may use for local industry during day. However, in Indian situation, flow rate is always fluctuating over the years such as water flow rate of streams are higher in rainy season and reducing toward summer. If impeller diameter and speed of PAT are constant then there is significant loss in efficiency due to reduction in flow rate. However, operating the PAT with different impeller diameters or speed, PAT can be operated without significant drop in efficiency even at reduced flow conditions. In this paper, simple approach based on characteristics of pump operated in reverse mode and affinity law is used to evaluate the best efficiency point with different impeller diameters. For lower difference of impeller diameters, affinity law held good and predict the PAT performance parameters with very small deviation. Keywords: Pump as turbine, reverse mode operation of pump, affinity law, variable impeller diameter conditions. Therefore, influence of impeller diameter on the performance of PAT should be 1. Introduction
Micro-hydro power can be one of the most important alternatives to isolated rural communities due to the advantages of electrification and the associated progress, as well as to improve the quality of life. It is one of the most commercial hydroelectric power technologies for rural electrification in world. When the centrifugal pump works in reverse mode it simply reduces the equipment cost and can be used as substitute to conventional turbine. Pump manufactures do not generally provide the characteristic curves of their pumps in reverse mode. Therefore, it is difficult to select appropriate pump to run as turbine (Yang et al. 2012). Additionally, throughout the year, flow rate of available water streams generally reduces as rainy season gets over in case of small hydro plants. On the other side, the maximum efficiency band for PAT is very small, results in loss of efficiency due to reduction in flow rate or load on the PAT, if appropriate selection is not done. The impeller diameter is one of the important parameter in the selection of PAT for the specific site
studied in detail to avail the benefits of PAT for variable operating conditions. Yang et al. (2012) had performed experimental and numerical investigation on impeller trimming for pump as turbine. Experimental research was carried out on a single stage centrifugal PAT, performance curves of original impeller, impeller after once and twice trims were acquired. In another paper, Yang et al. (2013) had carried out experimental work on three different sizes of impeller, 215, 235 and 255 mm. The PAT efficiency, pressurehead, shaft-power, and flow rate at the BEP are increased by 10.26%, 36.16%, 89.39%, and 26.14%, respectively, due to increase in impeller diameter ( from 215 to 255 mm). Jain et al. (2015) had performed experimental investigations for various impeller diameters. The experiments were performed at constant rotational speed of 1100 rpm with original diameter (250 mm), 10% trimmed impellers diameter (225 mm) and 20% trimmed diameter ISBN-978-81-932091-2-7
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(200 mm). According to Gulich (2010) the economical limitation of the trim ratio of large pumps operational behavior should be considered, since it may deteriorate if blade shortening through trimming is excessive. 1.1
Objectives of the Current Study
Based on the above literature review and available experimental facility in the laboratory, the following objectives has been planned: i. To perform the trials on a selected pump in reverse mode (PAT) with impellers of different diameters. ii. To compare the performance of pump in reverse mode at best efficiency point (BEP) for different diameters. iii. To verify the experimental parameters of PAT for different diameters at BEP by affinity law.
2.
Methodology:
The experimental and theoretical means are applied to accomplish above Objectives.
2.1 Experimental analysis A radial flow end suction type centrifugal pump with impeller diameter 214 mm is selected for reverse mode operation. The Pump parameters at BEP are specified as: flow rate 15.28 lps, head 14.28 m, power input 2.9 kW, and efficiency 74 % (shown in Figure 1). The experiment on selected PAT with different impeller diameters are conducted on an open loop type test setup. The test setup consists of a feed pump to supply water at high pressure to get necessary head and flow. Feed pump is driven by an electric motor, which is connected to variable frequency drive (VFD). High pressure water is supplied to centrifugal pump running as turbine through piping arrangement. After imparting energy to the impeller, this water is discharged into the sump through a draft tube. Head across the feed pump and PAT is measured using pressure transducers. Inductive proximity switches are used to measure feed pump as well as PAT speed. An electromagnetic flow meter installed in line is used to measure the flow rate. Detailed description of this PAT test rig is given by Doshi (2017). In order
to avoid over cutting the impeller, it is recommended that the trimming be done in steps with careful measurements of the results. At each stage, available experimental data can be used to predict the performance parameter for the next step and accordingly trimming diameter would be decided. Therefore, the PAT is tested for three different diameters viz. original impeller (ϕ 214 mm), 5% trimmed impeller (ϕ 205 mm), and 10% trimmed impeller (ϕ 195 mm). The data generated through experiments are processed for plotting of the characteristic curves such as head, power, and efficiency Vs. flow rate.
2.2 Theoretical Analysis of PAT The affinity laws are derived from a dimensionless analysis of three important parameters that describe pump performance: flow, total head, and power. The analysis is based on reduced impeller being geometrically similar and it is operated at dynamically similar conditions or equal specific speed. If that is the case then the affinity laws can be used to predict the performance of the pump at different diameters for the same speed or different speed for the same diameter. Current work is analyzing effect of different impeller diameters on the performance of PAT. Since in practice impellers of different diameters are not geometrically identical, the performance parameters in the pump recommend to limit the use of this technique to a change of impeller diameter. The simplified affinity laws with assumptions of similarity in the velocity triangles at inlet and outlet of PAT at BEP for different impeller diameter conditions used are: Q2 D2 Q1 D1
3
H 2 D2 H1 D1 P2 D2 P1 D1 Where,
(1) 2
(2)
5
(3)
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D is Impeller diameter, m; P is Power, kW; H is Net head, m; Q is Discharge, m3/s; subscript 1 is Impeller inlet (Turbine mode); subscript 2 is Impeller exit (Turbine mode)
3 Results and Discussions: The experiments were performed on PAT with three impellers of diameters viz. original impeller (ϕ 214 mm), 5% trimmed impeller (ϕ 205 mm), and 10% trimmed impeller (ϕ 195 mm) at rotational speed of 1000 rpm. To study the effects of impeller trimming on head, power and efficiency at different discharge the performance curves are plotted as shown in Figures 3, 4, and 5. All three results are superimposed in one single graph that will give the clear information about performance variation with trimmed impeller on PAT. In the plots of head and output power Vs. discharge (Figures 2 and 3), larger diameter impeller curve is above that of lower from part load to best efficiency point (BEP) and vase versa in overload region. This indicates that higher head is required to operate the PAT for larger diameter PAT in part load region, on the other hand, in over load region, higher head is required to operate the PAT for lower diameter PAT. Similar observation is equally valid for output power Vs. discharge plot as shown in Figure 3. The efficiency curve shown in Figure 4 for impeller diameters of original impeller (ϕ 214 mm), 5% trimmed impeller (ϕ 205 mm), and 10% trimmed impeller (ϕ 195 mm) indicates that at duty point efficiency of PAT is maximum, in part load, and overload region is dropping. In part load region, the efficiency curve is steep whereas in overload region slop of drop in efficiency curve is comparatively small. With increasing in the impeller diameter of PAT, it is observed from Figure 4 that the peak efficiency (BEP) is shifting towards higher flow rate. Further, this helps in operation of PAT where flow rate is reduced. If flow rate is dropped down, then it is always
advantageous to operate PAT at lower diameter than the diameter at which it is running such that it’s operating point for new condition will match with the duty point. From Figure 4 it is also devised that during selection pump for turbine operation it is better to select a pump of lower capacity and to operate it in the overload region so during operation of PAT due to drop in flow reduction in the efficiency is comparatively very small. Various parameters at BEP for different impellers are summarized in Table1. It may be noted that, the discharge, power output, efficiency, and Head decreased by 12.5%, 27%, 1.22% and 12% respectively with 205 mm diameter impeller. Further trimming result in decrease of all the parameters but not in greater extent. The decrease in parameter is causes due to the large separations inside the impeller passages with larger trimmed impellers. Table 2 presents the performance parameters at BEP determined by experiment and by affinity law. From Table 2 it is seen that at lower impeller diameter (ϕ195 mm) deviation in the flow rate prediction is 9.7 %, head prediction is 3.5 % and power prediction is 2 %. For impeller diameter, (ϕ205 mm) deviation in the flow rate prediction is 0.5 %, head prediction is 9.3 % and power prediction is 11.2 %.
4 Conclusions: In the paper, the state of art facility is developed for testing the PATs with sophisticated instrumentation and automatic control systems. Based on PAT characteristic curves obtained at various impeller diameter, PAT can be operated optimally (without much compromise of reduction in efficiency) to meet with variable flow conditions. For lager difference in diameter of impeller (small size compared to original impeller diameter), remarkable decrease in parameter is generally observed, which is because of large separations inside the impeller passages as the gap between mouth of the casing and tip of the impeller ISBN-978-81-932091-2-7
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2. 3.
4. 5.
Doshi, A., 2017. Influence of Inlet Impeller Rounding and the Shape of Non-Flow Zones on the Performance of Centrifugal Pump As Turbine. Sardar vallabhbhai National Institute of Technology, Surat, India. Gülich, J.F., 2010. Centrifugal Pumps. 2nd Ed. Springer-Verlag Berlin Heidelberg. 2nd Edition, Springer-Verlag Berlin Heidelberg, Berlin. Jain, S. V., Swarnkar, A., Motwani, K.H., and Patel, R.N., 2015. Effects of impeller diameter and rotational speed on performance of pump running in turbine mode. Energy Conversion and Management, 89, 808–824. Yang, S.-S., Kong, F.-Y., Jiang, W.-M., and Qu, X.-Y., 2012. Effects of impeller trimming influencing pump as turbine. Computers & Fluids, 67, 72–78. Yang, S.-S., Liu, H.-L., Kong, F.-Y., Dai, C., and Dong, L., 2013. Experimental, Numerical, and Theoretical Research on Impeller Diameter Influencing Centrifugal Pump-as-Turbine. ASCE Journal of Energy Engineering, 139 (4), 299–307.
12 8 4 0 0
2.5
Pressure Guages
VFD Panel
FeedPump
Control Valve
EddyCurrent Dynamometer
Conrtol Panel G.L.
TorqueSensor
Pressure Guages
2
Ground level
Test Bed
25
1.5 1
0.5 0 0
5
10 15 Flow rate (lps)
20
25
Figure 3: Power Vs. Flow Rate characteristic curves for PAT at different diameters 80 214 mm 205 mm 195 mm
40 20 0 0
5
PAT Motor
10 15 20 Flow rate (lpm)
214 mm 205 mm 195 mm
60
ElectroMagneticFlowMeter
5
Figure 2: Head Vs. Flow Rate characteristic curves for PAT at different diameters
Efficiency (%)
1.
214 mm
16 Head (metre)
References:
20
Power (kW)
becoming large. Testing of affinity law at diameter variation with large data can be future scope of work. This will increase the applicability of PAT operating at different diameters.
Draft Tube Ground level
CommonSump
Figure 1: Schematic Layout of PAT Test Rig (Doshi 2017)
10 15 Flow rate (lpm)
20
25
Figure 4: Efficiency Vs. Flow Rate characteristic curves for PAT at different diameters Table 1: Comparison of BEP parameters of different impellers Impeller
Q (lps)
H (m)
P (w)
Ƞ (%)
214 mm 16.716 205 mm 14.623 195 mm 14.074
11.561 9.704 9.276
1.309 0.944 0.838
69.090 67.862 65.505
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Table 2: Comparison of experimental and analytical parameters at BEP Efficiency Flow Rate Head, (m) Power, (kW) Diameter lps (η) mm % Experiment AffinityExperimentAffinity Experiment Affinity 214 205 195
69.09 67.86 65.50
16.716 14.623 14.69 14.074 12.64
11.56 9.70 9.27
10.60 9.59
1.309 0.944 0.838
1.05 0.822
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Renew your Inner Energy through Human Internal Energy Sources: A Practitioner and Theoretical Approach Shulbha Kothari, Shiv lal Government Engineering College Banswara, India-327001 Corresponding Author: shulbha1986@gmail.com Abstract This work deals with the human being renewals, which are most important for the good health and spiritual life. The global exergy phenomena can be utilized for human being is proved in this study. It applies to performance indicators for individuals under physical activity based on the concept of exergy destroyed and exergy efficiency. 1.
Introduction You can renew your lease when it runs out at the end of the year, you can renew your driver’s license and license plate on your birthday, you can also renew a library book when you allotted them with it has expired. All sorts of things get renewed in our everyday lives when they run out or expire. They are easy to renew because you don’t have to create new one, you just renew the ability to use whatever it is you are using. You can apply the same principle to natural resources. We use all kinds of natural resources minerals, wood, coal, natural gas, wind, water, plants, animals and many more, some of these are renewable and some are nonrenewable. The difference is that some renew at faster rates than others, making them more sustainable than those that do not renew very fast. Renewable resources are resources that are replenished by the environment over relatively short period of time. This type of resources is much more desirable to use because often a resource renew so fast that it will have regenerated by the time you have used it up. Think of this like ice cube maker in your refrigerator, as you take some ice out, more ice gets made, if you take a lot of ice out, it takes little more time to refill the bin but not a very long time at all. Even if you completely emptied the entire ice cube bin, it would probably only take a few hours to ‘renew’ and refill that ice bin for you. Renewable sources in the natural environment work the same way. Energy resources and their utilization intimately relate to sustainable development. In attaining sustainable development, increasing the energy efficiencies of processes
utilizing sustainable energy resources plays an important role. The utilization of renewable energy offers a wide range of exceptional benefits. There is also a link between exergy and sustainable development. A sustainable energy system may be regarded as a costefficient, reliable, and environmentally friendly energy system that effectively utilizes local resources and networks. Exergy analysis has been widely used in the design, simulation and performance evaluation of energy systems. 1.1 What Is Exergy? Exergy is a thermodynamic concept, used for many years within engineering analyses of chemical and mechanical processes and systems. Officially, exergy is defined as: “The maximum useful work which can be extracted from a system as it reversibly comes into equilibrium with its environment.” (1) The cardiopulmonary exercise test is one of the most used tests to assess the functional capacity of individuals with varying degrees of physical training. To perform the exergy analysis during the test, it is necessary to calculate heat and mass flow rates, associated with radiation, convection, vaporization and respiration, determined from the measurements and some relations found in the literature. The energy balance allowed the determination of the internal temperature over time and the exergy variation of the body along the experiment. Eventually, it was possible to calculate the destroyed exergy and the exergy efficiency from the exergy analysis. The exergy rates and flow rates are dependent of the exercise level and the body metabolism. The results show that the relation between the destroyed exergy and the metabolism is almost constant during the test, furthermore its value ISBN-978-81-932091-2-7
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has a great dependence of the subject age. From the exergy analysis it was possible to divide the subjects according to their training level, for the same destroyed exergy, subjects with higher lactate threshold can perform more work. Exergy analysis is applied to assess the energy conversion processes that take place in the human body, aiming at developing indicators of health and performance based on the concepts of exergy destroyed rate and exergy efficiency. The thermal behavior of the human body is simulated by a model composed of 15 cylinders with elliptical cross section representing: head, neck, trunk, arms, forearms, hands, thighs, legs, and feet. For each, a combination of tissues is considered. The energy equation is solved for each cylinder, being possible to obtain transitory response from the body due to a variation in environmental conditions. With this model, it is possible to obtain heat and mass flow rates to the environment due to radiation, convection, evaporation and respiration. The exergy balances provide the exergy variation due to heat and mass exchange over the body, and the exergy variation over time for each compartments tissue and blood, the sum of which leads to the total variation of the body. Results indicate that exergy destroyed and exergy efficiency decrease over lifespan and the human body is more efficient and destroys less exergy in lower relative humidity and higher temperatures. Among our most valuable resources is our energy- physical, mental, emotional and spiritual energy. Each of these is necessary for optimal health and wellness. We know that positive emotions can increase our energy and negative emotions can drain our energy. 1.1.1 Exergy is a measure of energy quality Energy comes in many different forms, all of a different inherent quality. ‘Quality’ can refer to a number of attributes – ease of transport, energy density, environmental impact, etc. – but we refer here to its most fundamental form, which encapsulates the ability to perform physical work, i.e. to overcome a resistance to make an object move. This is important when considering thermal energy (heat), which is
intrinsically of a lower quality than other forms of energy (such as electricity or mechanical motion) (2). This is because for a given amount of heat, a portion – depending upon its temperature – will constitute the low-grade waste heat which cannot then be recovered and made to do physical work (for example, in a heat engine).Exergy analysis is applied to assess the quality of the energy conversion processes that take place in the human body, aiming at developing indicators of thermal comfort based on the concepts of destroyed exergy rate, exergy transfer rate to the environment and exergy efficiency. In literature only destroyed exergy has been used to evaluate thermal sensation. To perform the exergy balance, it is necessary to calculate the exergy variation of the body over time which is a composition of metabolic exergy and the exergy variation due to transient environmental conditions. The exergy transfer to the environment is calculated as the sum of the terms associated with radiation, convection, evaporation and respiration. The thermal behavior of the human body is simulated by a model composed of 15 cylinders, naked and dressed for winter seasons, as a function of the air temperature, mean radiant temperature and relative humidity. The energy equation is solved to obtain transitory response of the body due to a variation in environmental conditions and the energy transfer to the environment. For relative humidity between 40% and 60%, results indicate that the destroyed exergy is minimal for thermal comfort conditions. Nevertheless, for low relative humidity and high temperatures the destroyed exergy is also minimal, indicating the necessity of another physical quantity to evaluate thermal comfort conditions. At this point the exergy transfer to environment is high, showing that the body may not be at thermal comfort condition. This article proposes is to use two terms of the exergy analysis to evaluate the thermal comfort condition: destroyed exergy and exergy transfer to environment. 2. Material & Methods Renewing our minds, transforming our heart-sound fait 2.1 Emotional Renewals 144
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2.1.1 Reduce Denial and “Clean House” Emotionally Everyone has defenses. We learn to cope with our emotional trials and issues by developing coping strategies. Some are positive, such as using relaxation, meditation, exercise, or participating in an enjoyable Denial is often difficult to recognize and change, because it involves a tendency to ignore or pretend that an issue does not actually exist. -Rita Milios recreational activity. Others are negative, such as worrying, denying, or withdrawing. Denial is often difficult to recognize and change, because it involves a tendency to ignore or pretend that an issue does not actually exist. Yet denial costs us emotionally. It takes a lot of energy to “keep the lid on” uncomfortable or unwelcome emotions. But if we actively deal with such issues, we not only enhance our lives emotionally, we also recover vital energy that can be used for other positive purposes in our lives. (3) Since denial is often maintained by distraction (use of substances, overspending, working excessively, etc.) and self-blame (internalizing an issue and automatically blaming one’s self without validating the need for blame), it is important to look for “the truth that can set you free” from distorted beliefs and see reality for what it actually is, not what you fear or worry that it is. Old, self-defeating beliefs from the past often direct our behavior, causing unwelcome consequences, whether we overtly recognize it or not. So, it behooves each of us to clear up the negative beliefs about ourselves that may be supporting our self-destructive behavior. 2.1.2 Write a Letter for Emotional Release One good way to dispel negative beliefs is to write a letter to yourself, detailing exactly why you feel emotions such as shame, guilt, worry, etc. Try to get all the negative emotions out of your body and mind, and transfer them to the written page. Do not judge what you are writing. When finished, set the pages aside for a day or so. Then, when you are ready, read them aloud. Consciously and logically determine if you should make amends and what these might be, taking into account how
any other persons affected may respond. (Do not re-offend by tearing open old wounds. If the others involved would feel more distress than closure, simply ask forgiveness of them mentally, and do not make actual contact.) Then, once you have processed the emotions, re-frame any negative beliefs about yourself and tear up or burn the letter. Affirm that the guilt, shame or worry has been released, and make a conscious intention to act as if this has occurred. 2.1.3 Be Aware of Your Feelings Throughout the Day Periodically, throughout the day, do an “emotional check-in” to see how you are feeling. Every hour or so, simply take a moment to evaluate: are you happy, sad, angry, frustrated, or feeling something else? Once you determine what you are feeling, if it is not a positive, helpful feeling, decide to change it. Do this by first desiring and intending to change your mood. Then visualize something that will produce the desired mood change in you. For instance, picture yourself doing something that makes you happy and proud of yourself. Then affirm, this is the feeling that I am encouraging in my mind. If you regularly “change the channel” of your mental and emotional state, you will create a habit of this mental and emotional re-adjusting process. Then your positive mood will be more likely to maintain itself without regular monitoring. If you regularly ‘change the channel’ of your mental and emotional state, you will create a habit of this mental and emotional re-adjusting process. -Rita Milios (3) 2.2 Spiritual Renewals 2.2.1 Connect with Nature Many of us find nature to be very renewing to our mind and spirit. Ironically, our busy lives often keep us from utilizing this valuable–and free–resource. But by making a conscious commitment, you can increase your exposure to the natural world and experience the recovery and renewal that being in nature provides. Simply taking a walk outdoors and noticing the environment – trees, water, sun, wind – brings your attention out of your own head, allowing you to relax mentally, and 145
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instead, note what you are experiencing from a higher, spiritual level. If you have access to a lake or ocean view, spending some time just watching waves roll in is very relaxing and renewing for most people. Even if you do not have this option available, you can listen to the sounds of waves via a sound machine or CD. Today, there are even some television programs that offer meditative music and visuals for relaxation and renewal. 2.2.2 Read Spiritual Literature Reading some inspirational or spiritual literature daily is a great form of spiritual practice. With such reading, you can temporarily remove yourself from the day’s pressures, concerns and challenges and allow your mind and body to rejoin with your higher spiritual nature. Even a few minutes of this kind of transcendent experience can dispel negativity from your mind and emotions and allow you to feel rejuvenated and re-energized on all levels. ‘Let me today respond to each person I meet with kind words, appreciation and patience.’Rita Milios You might also consider ways to bring this positive feeling into the rest of your day. One such option is to reflect on something that you are grateful for or something that you would like to set as an intention for the day. For example, you might affirm: “Let me today respond to each person I meet with kind words, appreciation and patience.” (4) 2.2.3 Attend a Spiritual Group Activity Being with others when we are involved in a spiritual activity often enhances the experience. For many people, attending church or a support group is uplifting and enjoyable. With like-minded people to share your spiritual experience with, you are also more likely to stay committed to a regular practice and therefore gain more of the positive benefits. It is worth taking the time to visit as many gatherings as necessary in order to find the group that fits you best. Finding a spiritual “home” can be one of the best things you do to renew and re-energize yourself.
2.3 Renewable Energy: How to Renew Your Physical and Mental Energy Energy a little low? Like many people, you may be experiencing a bit of seasonal letdown. Now that the excitement of the holidays has died down, January and February seem to loom ahead with nothing to offer but short, cold and often dreary days. The transition from a hectic but fun schedule to your regular, everyday routine can seem boring and somewhat depressing at first. Not only that, like many others, you may have expended so much energy over the past couple of months that you need rejuvenating – not only in body, but in mind, emotion and spirit as well. Fortunately, there are ways to do just that. This two-part article shares some rejuvenation and renewal techniques for all aspects of your being. So, take the next few weeks to explore, experiment and experience new ways to promote within yourself a more vibrant, energetic and renewed state. 2.3 Physical Renewals 2.4.1 Exercise It’s not a coincidence that many people embark on an exercise regime in January. Not only do many of us need to shed a few pounds that we gained by celebrating a bit too heartily, we also recognize that exercise, both literally and figuratively, can get you going. A 2008 study from the journal Psychotherapy and Psychosomatic (4) found that study participants achieved increases of energy of approximately 20 percent and decreases in feelings of fatigue of up to 65 percent, simply by participating in regular, low-intensity exercise. But calm energy, which combines high mental energy with low physical tension (such as Pilates, TaiChi, walking…), allows the body to avoid fatigue and actually increases your energy level. -Rita Milios(3) But not all exercise is created equal. According to Robert E Thayer, Ph.D., author of Calm Energy: How People Regulate Mood with Food (2001, Oxford University Press, NY) (5), there are actually two different types of energy–what he calls “tense energy” and “calm energy”–and they each have different effects on the body. Thayer says many of us typically utilize tense energy, working or exercising our 146
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bodies at a high, intense physical level, like when we work out at the gym. This kind of energy expenditure often makes you feel tired afterwards. But calm energy, which combines high mental energy with low physical tension (such as Pilates, TaiChi, walking and strengthtraining, if movements are done slowly and deliberately) (6), allows the body to avoid fatigue and actually increases your energy level. 2.4.2 Proper Sleep Deep sleep, which happens in cycles about every 90 minutes throughout the night, is crucial for physical renewal, hormonal regulation, and growth. Without deep sleep, we are more likely to get sick, feel depressed, and gain weight. But according to the National Sleep Foundation, only about 28 percent of us get enough sleep each night. We need 3 to 4 deep sleep cycles (about 7 to 8 hours of sleep) to allow our bodies to renew and repair themselves. Sleeping in a cool, dark room enhances the sleep experience, and allows for the most restorative sleep, experts say. 2.4.3 Deep Breathing One reason you may be feeling low on energy is that your cells may be starving for oxygen. Too many of us have gotten into the habit of breathing shallowly, which prevents air and oxygen from fully penetrating the lowest portions of our lungs. This kind of breathing can suck your energy and make you feel anxious, says Pam Grout, the Alternative & Complementary Medicine correspondent at the Dr. Oz health website. To help you breathe better, practice taking full diaphragmatic breaths for several minutes a few times a day. The Harvard Mental Health Letter offers these suggestions: You’ll notice that shallow breathing often feels tense and constricted, while deep breathing encourages relaxation. -Harvard Mental Health Letter (7) Start by observing your breath. First take a normal breath. Then take a slow, deep breath. The air coming in through your nose should move downward into your lower belly. Let your abdomen expand fully. Now breathe out through your mouth (or your nose, if that feels more natural). Alternate normal and deep breaths several times. Pay attention to how you feel when you inhale and exhale normally and
when you breathe deeply. You’ll notice that shallow breathing often feels tense and constricted, while deep breathing encourages relaxation. 2.5. Mental Renewals 2.5.1 Meditation: Give Your Left-Brain a Break Most of us are left-brain heavy. We use our thinking, processing left-brain more than our creative, intuitive right-brain. You can refresh and renew your whole mind by giving your left-brain some down time. Meditation slows brain waves and “re-sets” your brain, increasing mental clarity and improving your problem-solving ability while relaxing you. An easy way to meditate is to simply notice your breath and put your full attention there, noticing how it feels for your lungs to expand and your diaphragm to recoil. You can also repeat a word or mantra, such as “peace” or “relax” with each breath. Even a short 5 to 10minute meditation, practiced regularly, can provide significant benefits. 2.5.2 Balance Your Brain You can achieve even more left-right brain balance and mental renewal by doing a brain balancing exercise: Close your eyes and visualize your brain inside your head. Picture the left and right sides, with the corpus callosum, or centerline, between. Imagine that each side is filled with an energy-filled fluid, and that on the left side the fluid level is higher than on the right. Imagine “poking holes” in the corpus callosum that separates the two sides of your brain, so that the energy-fluid can flow from the left side to the right side, until the two sides are leveled out. Affirm to yourself, “My brain’s energy is now balanced and I am centered.” 2.5.3 Power Nap Do you regularly nap for 10 to 30 minutes between the hours of 1 p.m. and 4 p.m. most days? If so, you are a “power napper” and according to Sara Mednick, researcher and author of Take a Nap! Change Your Life (Workman Publishing; 2006), you are boosting your alertness and possibly improving your memory as well. Apparently, the publishers of Mednick’s book were so impressed with her research regarding the benefits of power napping that they created “napping rooms” so 147
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that their employees could refresh themselves during the work day. More companies are also approving power napping for their employees, and seeing improvements in their productivity as a result. 2.6 How to Manage and Revitalize Your Personal Energy 2.6.1 Energy, Health, and Conscious Living One of the major health issues affecting people today is lack of energy. The energy crisis we are currently facing is not limited to our environment and the planet we live on. The crisis extends to each one of us, and the bodies we live in. More and more people suffer from stress related illnesses. In fact, research suggests that as many as 80-85% of all disease and illness is caused by stress.1 The technological age that promised extended free time and increased leisure is draining us energetically. Work pressures, relationship issues, parenting, financial worries and fears for the future, all drain energy and create stress. Stress leaves us feeling tired, wound up and low in energy. In our fast paced, I need it yesterday world the only constant is change. And when everything changes we must adopt new coping mechanisms. How we manage personal energy is the new key to creating a high quality of life. 2.6.2 Managing Personal Energy Most of us want enough energy and vitality to live life to the fullest. We don’t want to feel drained, exhausted and stressed out all the time. And why should we when being full of energy is our birthright. Energy is the fuel humans are designed to function on. We need regularly topped up, good quality energy for optimum health and wellbeing. Everyone is familiar with energy and describes it in different ways. How many times have you said or heard others say ‘I feel full of energy’ or ‘I am low on energy’? You may have heard people speak of ‘having no energy left at all’? (8)We speak of liking and disliking someone’s energy or vibration. Energy is very much part of our experience and common language. [ AMA Business Week 2003] 2.6.3 How One’s Energy Gets Drained Energy has been the focus of my work for over the last twenty-five years. As a Health and
Success Coach I have had the privilege of working with thousands of people all over the world. From my experience I have observed five main ways people allow their personal energy resources to get drained. 1. Overwork is the number one energy zapper. The culture of working long hours in the office or working from home without clear boundaries causes tiredness, poor concentration and eventually leads to exhaustion. 2. Reluctance to exercise takes the number two spot. We all know the benefits of exercise yet travelling by car and sitting down all day creates insufficient movement, which is a major energy zapper and cause of stress. 3. Poor diet is another issue, with people eating foods lacking in vitality and nutritional value. Eating on the move and yo-yo dieting prevent nutrients being adequately absorbed. We need to consume foods that provide energy and sustain life. Most of us know the theory of what to eat, yet still fall prey to all manner of poor eating habits. 4. Constant worrying is another way energy gets depleted. People often entertain fears and play out dramas, in the mind, that never happen in real life. Not to mention carry the weight of the world on their shoulders. Can you imagine how much energy that takes? 5. And on top of all that there never seems to be enough me-time to refuel. Think about it, even cars get an oil change and a regular service. No one expects a vehicle to run on empty and I am sure you always give your car the best fuel you can afford. So how about your body? Surely you deserve the best. What is the key to good health, optimum function and living life to the full? 3. Conclusion 3.1 Energy is the Fundamental Building Block of Life We have seen that energy is the fundamental building block of life. We know that modern living encourages the use and abuse of our personal energy resources. What then is the way forward? My research over twenty-five years has involved the study of energy, holistic healthcare, psychology, spirituality and new 148
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paradigm medicine. I traveled worldwide and experienced how people maintain health and achieve success in different cultures. This led me to develop a powerful energy-based approach to balanced living. I literally took the most potent, quick acting, easy to use techniques for energy management and created a new approach to health and conscious living. Having uncovered the five main energy zappers, I looked at ways energy could be restored and revitalized. I knew from my work in holistic health care that there is absolutely no need to wait to get ill before making life changes that positively impact your health and wellbeing. Therefore, we explore four main ingredients that are guaranteed to get energy flowing and not only to restore energy levels but also to prevent illness; creating healthy, happy and successful lives in the midst of a changing world. The four main ingredients are: Energy Exercises to re-energize your body Energy Psychology to release stress and free your mind Energy Foods that re-vitalize your system Energy Balance to relax and calm you Creating abundant energy is not as difficult as it seems. The magic of this formula is that it can be used to revitalize energy anytime and anywhere. A few minutes every day can make an enormous difference to your energy levels and quality of life. 3.2 How to Revitalize Your Personal Energy I strongly believe in the dictum, less is more. Don’t sweat the small stuff and Pareto’s 80-20 law definitely works for me. The Italian economist Pareto said that 20% of your energy creates 80% of your results. That means most of what you do creates very little. For example, 20% of your wardrobe accounts for 80% of what you wear. 20% of the world’s population uses 80% of its resources. Does that make sense? It’s all about learning to master energy. So don’t underestimate the power and simplicity of the following exercises. The secret of this lies in the simple things you can add into your day to create maximum impact. Didn’t Duke Ellington once say, “I merely took the energy it takes to pout and wrote some blues”.(9) That is energy mastery and the
simple exercises below can help you achieve it. 3.2.1 Breathe and Relax. For just two minutes stop what you are doing, slow down and be completely mindful of your breath. This re-oxygenates, rejuvenates and relaxes your body-mind, which in turn creates calm and greater clarity. If you doubt two minutes can make a difference, try it. Regularly incorporate mini vacations into your day. I recommend two minutes in every hour. 3.2.2 Get out of your head and into your body. Especially if you usually sit at a desk all day. Take a moment to stretch with awareness. Rotate your neck, arms and shoulders to release any tightness. Walk upstairs, stretch your ankles and feet to improve circulation, release blockages and elevate energy. 3.2.3 Inner smile Great for releasing negative energy. Close your eyes and visualize your lungs smiling, then see your heart smiling and your liver, your intestines and all your internal organs one after another. This is hard to do without bringing a smile to your face and releasing negativity. Negative emotions create disease, so let go of any stored negativity and give yourself a big inner smile. 3.2.4 Make use of nature’s perfect health drink H2O. There is no better way to lift energy than by drinking water. Fatigue, headaches, digestive problems and low energy levels are often removed simply by drinking more water. 75% of the population are dehydrated. So next time you feel low, reach for the H2O. The energy crisis we are experiencing can be alleviated with more awareness of how we go through each day. It’s important to remember that the flow of energy in the human body, mind and spirit is the foundation of health and success. Human power used to be all the rage. 150 years ago, products that relied on human energy such as the bicycle, pedal-powered lathe or sewing machine could be found in most households. But as electro-mechanical motors developed, reliance on human-powered products gradually diminished. 149
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Today, human power is not appropriately recognized for its potential as an alternative solution to our growing energy needs. Indeed, as we search for more renewable energy sources, is it possible to abandon using traditional electricity for certain tasks and return to human power? The way that more and more products are becoming digital and even internet-connected makes this a challenge. But humans emit energy that can easily be harnessed from our everyday behavior. The bicycle is a great way of using human power in a way that allows us to exercise, transport ourselves and save on the consumption of conventional energy at same time. If, for example, we can design bicycles to become more entertaining for people to use, they could encourage more people to adopt human power in this way. For example, London-based company Electric Pedals is using the pedal-powered technology to generate electricity for events such as outdoor cinemas, educational workshops and music stages. Human-powered products also have the potential to encourage us to become more physically active. According to the British Heart Foundation, around 32% of adults spend six hours a day during the week being sedentary, which means too much sitting and not enough exercise. According to my calculations, if these individuals spent half of their sedentary time exercising on a pedalpowered television, approximately £49 million worth of electricity could be generated per year, with a lot of calories burned on top. Using human-powered products as a countermeasure to our increasingly sedentary lifestyles could create a credible new perspective towards exercise as an alternative energy source. In some respects, human-power can be seen as the cleanest renewable energy source available, with great potential for helping people stay healthy and have fun. The human body contains enormous quantities of energy. In fact, the average adult has as much energy stored in fat as a one-ton battery. That energy fuels our everyday activities, but what if those actions could in turn run the electronic devices we rely on? Today,
innovators around the world are banking on our potential to do just that. Movement produces kinetic energy, which can be converted into power. In the past, devices that turned human kinetic energy into electricity, such as hand-cranked radios, computers and flashlights, involved a person's full participation. But a growing field is tapping into our energy without our even noticing it. References 1. Ibrahim Dincer, Marc A. Rosen, “Exergy: Energy, Environment and Sustainable Development” 2nd edition Elsevier 2. SciIll Staff , “Credit: Adam Boesel” January 29, 2009. 3. Rita Milios, ”Health and Wellness, Living in Recovery, Living with Addiction” January 2, 2015 4. Stephen R. Covey, “7- Habits of Highly Effective People”, Free Press, 1988 5. Robert E Thayer, Ph.D., “Calm Energy: How People Regulate Mood with Food”. 2001, Oxford University Press, NY, 6. Tony Schwartz, Catherine McCarthy Manage “Your Energy, Not Your Time” 7. “A spiritual and physical renewal Review of The Empower Yourself Project”, https://www.tripadvisor.in/ShowUserRev iews-g309253-d7307148-r361558185The_ Empower_ Yourself_ ProjectTamarindo_Province_of_Guanacaste.htm l, retrieved on December 08, 2017 8. Kathleen Barton, Renewal for Your Mind, Body and Spirit, Tuesday, 15 May 2012 19:21 9. Daniel Henderson, “Emotional Equilibrium” Reviewed 4 April 2016, 10. Rita Milios, “Health and Wellness, Recoveries” December 29, 2014 11. AMA Business Week 2003
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Renewable Energy Management for Smart Cities of India Daljeet Singh, Surya Prakash Meena Department of Mechanical Engineering, Govt. Engineering collage, Banswara 2015pie5168@mnit.ac.in, suryaprakashmn@gmail.com Abstract: In the previous couple of years numerous ground-breaking promises have been made about the prospective of the Smart City. A smart city is a sensible and resourceful urban center that gives a high value of life to its population through most favourable organization of its resources. Electricity management is one of the most traumatic problems within such urban centres attributable to the complexity of the energy systems and their critical function. The potential of cities is predicated perceivably on improved electricity environment and provides reliable24X7 electricity to consumers. In the last years India has actively promoted the smart grid, renewable energies for residential and tertiary buildings and focus should be on green buildings and green transport to reduce the need for electricity. This paper investigates the term of smart city, classified Renewable energy source for smart city of India. The benefit of application of Renewable energy management is that it will lessen entire cost of electricity, develop sustainability, and increase customer fulfillment. Key Word: Smart city, Renewable Energy.
1.
INTRODUCTON The current trend in our utilization of the earth’s resources is unsustainable and is making major surroundings issues. Temperature change resource depletion, loss of diversity, and pollution has a serious impact on many voters and therefore the earth, and that we ought to modification our current behaviour. Our gift use of the earth’s finite resources cannot be maintained. We want to makeover to property development, that ’meets the requirements of this while not compromising the power of future generations to satisfy their own needs [1]. The environmental burden could be operating of population, wealth, and technology and dominant the primary two factors are very difficult. The larger the population, the lot of impact it's upon the planet. Additionally, the overwhelming majority of individuals aim to affluent lifestyles, and wealthier folks consume way more resources than less affluent folks. Technology is each an explanation for the environmental burden and additionally a possible resolution. Technology like coal-fired power stations provides the electricity we want to support Associate in nursing affluent fashion,
however at constant time it creates carbon emissions that contribute to heating. instead, renewable energy technologies supported wind and solar, as an example, square measure doable solutions for property, although every has negative consequences in addition (e.g., the energy and materials needed to construct wind turbines or solar panels) [2]. A Smart town is associate in nursing urban Development to enhance the standard of life exploitation varied varieties of technologies and to enhance the potency of services. Smart town applications square measure developed with the goal of up the management of urban flows and letting real time responses to challenges. The Smart city's assets embrace native department’s data systems, schools, libraries, transportation systems, hospitals. For creating a town sensible, Renewable Energy is best to use in cities [3]. Renewable energy plays a very important role within the long-run energy provides security, diversification of energy combines, energy access, environmental security and property. Renewable energy is absolute to play Associate in nursing increasing role in future energy systems.
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2.LITERATURE : A lot of existing literature review articles is accessible on the standalone ways that of Renewable energy and sensible town; still some endeavours are created by the researchers within the past to rearrange and recreate the present state of affairs of Renewable energy in smart city. Joshi, S. and Joshi, F. (2016) appearance at problems, challenges for alternative energy plants and solutions to beat challenges. The solar smart cities will be with efficiency developed with utilization of solar power. ample solar radiation is obtainable in states like Rajasthan, Gujarat, Maharashtra, Tamilnadu and few others states as mentioned higher than. solar systems put in on rooftops of residential, commercial, institutional &amp; industrial buildings premises will solve the energy crisis also will become a supply of financial gain because it will be -fed into the grid at regulated feed-in tariffs or -used for self-consumption with net-metering approach. Optimum utilization of solar power is going to be welltried to be a boon to the society by its sustainable development. India will become a developed nation by creating sensible cities and sensible villages. Calvillo et al. (2016) this paper has two main objectives. The primary is to develop in view in to the quality of the energy-related activities during a smart-city context by reviewing advances and trends and by analyzing the synergies among totally different intervention areas. Moreover, a number of them typical applications commencement the literature for the assorted energy areas, also as operation and designing tools area unit reviewed. The second objective is to help stakeholders and policy manufacturers in the design of energy solutions for smart cities by providing ways for the effective modelling and management of energy systems and by reviewing existing comes and computer code tools. These ways embody the foremost relevant parts and customary sources of data needed for his or her mathematical modelling. Albino et al. (2015) this paper makes an attempt to clarify the means of a plan that's obtaining progressively popular—that of the smart town. Associate degree in-depth analysis of the literature disclosed that the means of a
smart town is multi-faceted. Descriptions of smart cities are currently as well as qualities of individuals and communities also as ICTs. Several parts and dimensions characterizing a smart town emerged from the analysis of the present literature. Results show however difficult the measure of a wise town is. Some attempts to form blanket indexes are reviewed. However, this paper wasn't meant to outline a brand new framework for the assessment of the smartness of a town, since the authors believe that such associate degree assessment ought to be tailored to a selected city’s vision. A universal fastened system is also tough to outline with the variability of characteristics of cities worldwide. However, it's been created clear that the definitions exhibit by explicit cities occupation themselves “smart cities” lack catholicity. Brenna et al. (2012) looks at Challenges in Energy Systems for the Smart- Cities of the long run. The study reportable during this paper takes place in accordance with the European policy and national ways for environmental property and energy security, per the Horizon 2020 objectives that include: promoting distributed generation systems; promoting cogeneration (combined heat and power systems, CHP) additionally for residential, tertiary and commercial buildings; the preparation of property quality through the employment of electrical vehicles; Promoting the rational use of electricity through actions geared toward edge energy expenditure and therefore the development of near-zero energy buildings. to the current purpose, several analysis studies area unit geared toward learning intelligent network (smart grid), that will enhance the management of the distribution network. Sinha et al. (2011)This paper discusses concerning the smart grid initiatives in India, implementation methodology, challenges and edges. The paper discusses the requirement for smart grid technology to attenuate the AT &amp; C losses that could be a burning issue across all power distribution utilities in India. The authors have highlighted some aspects of varied key areas connected on smart grid initiative for Indian Power distribution utility like AMI, GIS, CRM, EAM, DMS etc. ISBN-978-81-932091-2-7
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Additionally, elaborates the methodology to implement the smart grid project in Indian power situation. Morvaj et al. (2011) this paper aim was to develop a system that is operable for additional development towards as well as alternative . 3. RENAWBLE ENERGY IN SMART CITIES OF INDIA
The Ministry of new and Renewable Energy later has Collaborated with the Ministry of Urban Development in providing renewable energy from sources like daylight, wind and electricity for the good city’s electrical grid. a complete of 37288 MW of power were with success made for the smart cities, out of that 4345 MW of power were made from solar power, 4419 MW of power made from biomass and 24377 MW of power made from Wind Energy. The Ministry of latest and renewable energy aims to supply a complete of one hundred seventy-five GW of electrical power,100 GW from solar,60 GW from Wind energy,10 GW from electricity plants, and five GW from Biomass. As for the solar energy, The MNRE aims to supply twenty GW from solar Parks, ten GW from jobless Youth/Farmers, thirty GW from Govt./Private corporations like
4.
CONCEPT AND DEFINATIONS
A. smart city: We outline a smart city as a town that frequently will increase its performance in satisfying all desires of its citizens. This is aligned with definitions in literature, wherever a smart city may be a town that mixes ICT with its physical infrastructure to enhance conveniences, facilitate quality, add efficiencies, conserve energy, improve the standard of air and water, establish any issues within the operation of town systems and fix them quickly, recover apace from disasters, collect knowledge to form higher choices and deploy resources effectively and expeditiously. It can't be viewed as a add of components however holistically as a network of interconnected infrastructures obsessed on one another. It usually debated whose infrastructures and systems are those that create the core of the smart town however typically they're often narrowed all the way down to the following:
important infrastructures and ultimately a bigger scale between totally different systems very important to a wise town. At this stage electricity was investigated through a little scale smart grid consisting of five smart buildings. Essel, Sun-Edison, Lamp; T, etc., and forty GW from solar rooftop. The Honourable Prime Minister Shri Narendra Modi’s vision of creating a hundred smart cities were with stress to good Energy which has Renewable energy generation, smart grid and guaranteed electricity provide, and sustainable development. The good Cities pointers insist that 100% of the full electricity be made from solar power. Therefore, MNRE has set to supply electricity from solar power in homes and offices by victimization solar panels within the top side, Solar water heaters for warm water, solar PV top side for electricity, solar Street Lighting, solar Pumps for water lifting, solar concentrators for steam primarily based change of state and solar traffic signals. The MNRE additionally needs to market energy economical buildings on solar passive style.
1. Citizens, 2. Water and energy. 3. Communication, 4. Business, 5. Transport, 6. Town services, B. Smart grid: Incorporation of the smart grid technology within the smart cities project can supply a novel chance to leap into associate improved electricity setting and supply reliable 24X7electricity to customers. Through smart grids it'll be doable to integrate the coal and fossil fuel generated electricity with the solar and wind. this can cut back fuel use and encourage worth drops in renewable technology. Further, current smart grids also are building the technology to integrate consumerowned energy systems which is able to profit customers any – they're going to not have to be compelled to get the electricity generated by themselves. The sensible grid (Refer Fig1) delivers electricity to shopper’s exploitation ISBN-978-81-932091-2-7
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two-way digital technology to alter the for growth of its high technical school and additional economical management of telecommunications sectors. consumers’ finish uses of electricity still because the additional economical use of the C. Smart meter grid to spot and proper provide demandTraditional meters will solely offer imbalances in a flash and observe faults in an unidirectional info and should be browse in the exceedingly “self-healing” method that flesh by a meter reader. Smart meters are digital improves service quality, enhances meters that provide two-way communication responsibility, and reduces prices. The rising permitting additional interactivity between the vision of the smart grid encompasses a broad patron and utility. a smart meter are often water, set of applications, as well as computer code, gas, electricity and warmth meter. During this hardware, and technologies that alter utilities to paper it refers to a smart electricity meter. integrate, interface with, and showing Characteristics of a smart meter are: intelligence management innovations. Close to or period activity of a consumption of Key objective of smart Grid the Electricity usage and also the quantity of the Self-healing: The grid apace detects, electricity Generated locally; analyzes, Responds, and restores Are often browsing each remotely and locally; Empowers and incorporates the client: Utilities may use the sensible meter limit the Ability to include consumer instrumentation number of electricity progressing to or from the and behaviour in grid style and operation sensible building or even utterly disconnect the Tolerant of attack: The grid mitigates and is customer. resilient to physical/cyber-attacks The smart meter acts sort of a entry for the smart building to speak with the remainder of Provides power quality required by 21stthe grid. GSM, Broadband over transmission century users: The grid provides quality line (BPL), WiMAX, net and alternative power per shopper and business desires wireless communication standards are often Accommodates a good style of provide and used as a customary for the communication. demand: The grid accommodates a spread of This communication is bidirectional. Utilities resources, as well as demand response, will browse the meters remotely in real time combined heat and power, wind, and that they will send worth signals to the tip photovoltaic’s, and end-use potency customers. Customers have an summary of their Totally permits and is supported by consumption and worth of the electricity in real competitive electricity markets. time. By that approach customers will reply to Need for smart Grid in India: the occurrences within the grid that is that the With such monumental deficiencies in basic idea of the demand response. infrastructure, why would India| need to think D. Smart Building about investment in smart grid technologies? The term smart buildings are used for over a Ultimately for India to continue on its path of twenty year to introduce the idea of networking aggressive economic process, it has to build a devices and instrumentation within the building, contemporary, intelligent grid. it's solely with a and energy potency. In last half of Seventies, it reliable, financially secure sensible Grid that had been a building that was designed India will offer a stable setting for investments employing a idea of energy potency and in in electrical infrastructure, a necessity to fixing Eighties it had been a building that would be the basic issues with the grid. While not this, controlled from a house computer. Today, smart India won't be able to keep step with the buildings use the Seventies and Eighties idea growing electricity desires of its cornerstone with extra subsystems for managing and industries, and can fail to form associate setting dominant renewable energy sources, house appliances and energy consumption exploitation ISBN-978-81-932091-2-7
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most frequently a wireless communication technology. ICT permits sensible buildings to speak each with its within devices and appliances, that they'll additionally management, and with its surroundings. What is more, they'll adapt to grid’s conditions and communicate with alternative buildings, therefore making active small grids or virtual power plants. Sensors - watching and submitting messages just in case of changes; Actuators - playing a physical action; Controllers – dominant units and devices supported programmed rules set by user; Central unit – enabling programming of units within the system; Interface - the user communication with the system; Network - permits communication between the units Smart meter - offers two-way, close to or period communication between client and utility company Sensors, actuators, controllers, central unit, interface with network customary create a building automation. The smart energy building has additionally to mentioned elements additionally energy storage and little renewable energy supply.
5.
CONCLUSION
Smart town construct may be used for reworking any town into a sensible town. Smart town have numerous overwhelming advantages &amp; it a win – win scenario for each, government &amp; the citizens. So as to realize best energy management in a very complicated system sort of a good town, not solely do most of its energy components have to be compelled to be known and studied, however the implicit relations among them even have to be thoughtabout. Supported this study, some clear trend scan be known altogether intervention areas, taking advantage of advance sin technologies and reduced costs.
References [1]. Naphade, M., Banavar, G., Harrison, C., Paraszczak, J., & Morris, R. (2011). Smarter cities and their innovation challenges. Computer, 44(6), 32-39. [2]. Mathiesen, B. V., Lund, H., Connolly, D., Wenzel, H., Østergaard, P. A., Möller, B., ... & Hvelplund, F. K. (2015). Smart Energy Systems for coherent 100% renewable energy and transport solutions. Applied Energy, 145, 139-154. [3]. Lombardi, P., Giordano, S., Farouh, H., & Yousef, W. (2012). Modelling the smart city performance. Innovation: The European Journal of Social Science Research, 25(2), 137-149. [4]. Joshi, S. B., & Joshi, F. M. Role of Solar Energy Applications in Developing Smart Cities of India. Proceedings of national conferencece on Recent Advances in Computer Science and Technology (RACST-16), Oct, 16. [5]. Calvillo, C. F., Sánchez-Miralles, A., & Villar, J. (2016). Energy management and planning in smart cities. Renewable and Sustainable Energy Reviews, 55, 273-287. [6]. Albino, V., Berardi, U., & Dangelico, R. M. (2015). Smart cities: Definitions, dimensions, performance, and initiatives. Journal of Urban Technology, 22(1), 3-21. [7]. Brenna, M., M. C. Falvo, F. Foiadelli, L. Martirano, F. Massaro, D. Poli, and A. Vaccaro. "Challenges in energy systems for the smart-cities of the future." In Energy Conference and Exhibition (ENERGYCON), 2012 IEEE International, pp. 755-762. IEEE, 2012. [8]. Sinha, A., Neogi, S., Lahiri, R. N., Chowdhury, S., Chowdhury, S. P., & Chakraborty, N. (2011, July). Smart grid initiative for power distribution utility in India. In Power and Energy Society General Meeting, 2011 IEEE (pp. 1-8). IEEE. [9]. Morvaj, B., Lugaric, L., & Krajcar, S. (2011, July). Demonstrating smart buildings and smart grid features in a smart energy city. In Energetics (IYCE), Proceedings of the 2011 3rd International Youth Conference on (pp. 18). IEEE
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Design Aspects of Small Scale Wind Turbines: A Review Ankush Jain, K. B. Rana, B. Tripathi Department of Mechanical Engineering, Rajasthan Technical University, Kota-324010, India Corresponding Author E-mail: ankushjain03@gmail.com
Abstract The limited nature of fossil fuels is an important incentive for global transition towards renewable energies. One of the viable sustainable energy sources is wind. The large-scale wind farms are not a good option due to their undesirable effects on environment; hence installation of small scale wind turbines (decentralized grid system) is a sustainable option. This paper presents review on design of different types (i.e., horizontal axis and vertical axis) of small scale wind turbines. The blade design, control, aerofoil and aero-acoustic aspects of small scale wind turbines were reviewed. Keywords: Small scale wind turbines, Blade design, Aeroacoustics, Aerofoil 1. Introduction: Nowadays the world is facing problem due to energy crises, energy production rate is lagging the energy demand. The power generation is mainly dependent on fossil fuels, which is nevertheless having its negative impact on climate. Renewable energy is one of alternative options for eliminating fossil fuelbased power production. Wind energy is a promising technology which can contribute to reduce of carbon credit and reducing the polluting factors accumulated due to use of fossil fuels. In wind turbines the kinetic energy of wind is used to develop rotational power over the shaft. According to world wind energy association, the worldwide wind energy capacity extended to 486661 MW by the year of 2016, out of which 54846 MW were installed in 2016. This represents the growth rate of 11.8 % whereas in 2015 it was 17.2%. Approx 5% of total world electricity demand is full filled by the wind power. Latin America and China has increased their share of new wind power project installations to 6.5 % and 5.3 % respectively. The general technique in the field of wind energy harnessing is the use of unitary big capacity utility scale wind turbine. The utility scale wind turbines are deployed to supply power to large number of consumers by a single unit. The utility scale wind turbine is a centralized large sized wind turbine which requires a huge amount of financial investment and organizational set up. In contrast regarding the case of utility scale wind turbines some
researchers have found the negative outcomes over climate. Wang et al. (2010) found by his exhaustive review that deploying large scale wind turbine to get 15-25% power demand of world it can lead to increment of 10C of ambient temperature. Similarly, Fiedler et-al (2011) did a survey for 62 warm seasons, on a particular climatic model and found that it can lead to 1% increase in precipitation rate and occurrence of larger precipitation for the places where large scale wind farms exist. Small scale wind turbines which are with capacity ranges of 1 kW or even less have their own advantages. The chief advantages are; small scale wind turbine can be brought and set up by an individual with a small monetary investment and no organizational set up is required. Small scale wind turbine can be implanted over the roof top of building and the supervision required for that purpose is not of that much degree as compared to utility scale wind turbine. In 2015, a cumulative total of at least 990000 small wind turbines were installed all over the world. This is an increase of 5% compared with the previous year, when 945000 units were registered. It means that worldwide several million families are getting power from small scale wind turbine. However only in Italy the number of new installations increased during 2015. The recorded small-scale wind capacity installed worldwide has reached more than 945 MW as of the end of 2015. This is a ISBN-978-81-932091-2-7
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growth of 14 % compared with 2014, when 830 MW were registered. According to World wind energy association, China accounts for 43 %, the USA for 25 %, UK for 15 %, and Italy for 6.3% of the global capacity. Small scale wind turbines are gaining their importance around the globe. In July 2012, a new kind of feed-in tariff was approved by Japan in order to boost the country's production of wind and solar energy production. Small scale wind power turbines soon will be subsidized at least 57.75 JPY (about 0.74 USD /kWh). In UK, the people in rural or suburban parts of the UK can select for a wind turbine accompanied with an inverter to supplement local grid power. The UK's Micro-Generation Certification Scheme (MCS) has a provision of feed-in tariffs to owners of qualified small wind turbines. The owners can now install a micro renewable energy system and shall be getting paid for that (Bahaj et al., 2006). Small scale wind turbines are also handy in some autonomous applications which require a very high level of reliability. Some units are designed very light weight in their structure, e.g. 16 kilograms, allowing sensitiveness to minor wind motions and a rapid response to wind squalls typically found in urban settings. Some are easily mountable such like a television antenna. These wind turbines can be used as are liable source of energy when they are sized properly and are used at their optimum conditions. This paper presents a literature review on general classification and design aspects (blade design, control, aerofoil and aero-acoustic) of small scale wind turbines. 2. Small Scale Wind Turbines: There is no fix threshold limit in regards of any feature of wind turbine to separate the utility scale wind turbine from a small-scale wind turbine. However, the small wind turbines rotor is usually of 1.5 to 3.5 meters in diameter which can produce 1-10 kW of electricity at their optimal wind speed (Tummala et al., 2016). Fig. 3 shows the classification of wind turbines based on rotor diameter. Table 1 demonstrates the classification of wind
turbines based applications.
on
power
rating
and
Small scale wind turbines mainly can be classified based on the axis of rotation i.e., vertical and horizontal. Vertical Axis Wind Turbines (VAWT): Vertical axis wind turbines are those whose rotor axis is in vertical direction. These turbines do not have any yawing mechanism or self-starting capability. The generator location for these turbines is on ground and their height of operation is very low, hence making them easier for maintenance. The ideal efficiency for these turbines is more than 70%. The vertical axis wind turbines are classified into two major types: (i) Darrieus Wind Turbine: The Darrieus wind turbine is a type of vertical axis wind turbine which consists of a number of straight or curved blades mounted on a vertical framework. These turbines work from the lift forces produced during rotation. (ii) Savonius Wind Turbine: Savonius wind turbines are drag based wind turbines consisting of two to three scoops. These turbines have an ‘S’ shaped cross section when looked from above. As they move along the wind, they experience lesser drag and this difference in drag helps these turbines to spin. Due to the drag, the efficiency of these turbines is less when compared to other types of turbines.
Fig. 1: Classification of wind turbine according to capacity (Tummala et al., 2016) ISBN-978-81-932091-2-7
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Table 1: Wind turbine classification based on power rating and applications. Scale
Power rating
Micro
50W to 2 kW
Small
2 kW to 40 kW 40 kW to 999 kW More than 1 MW
Medium Large
Rotor diameter Less than 3 m
Application
3 m to 12 m
Homes and farms
12 m to 45 m 46 m and larger
Village power, Hybrid system Central station wind farms
Remote
Horizontal Axis Wind Turbines (HAWT): Turbines whose rotor axis is in the horizontal direction are called as horizontal axis wind turbines. Unlike vertical axis wind turbines, horizontal axis wind turbines have the ability to self-start and yaw. These turbines are highly dependent on wind direction and hence they are generally operated at higher heights than the VAWT. The ideal efficiency for these turbines is between 50% and 60%. Today most of small wind turbines are found to be traditional horizontal axis wind turbine, however vertical axis wind turbines are also a growing type of wind turbine in the small scale wind market. Nevertheless, some small wind turbines are designed to work at low wind speeds, but in general small wind turbines require a minimum wind speed of 4m/s for better performance. 3. Effects of Design Parameters on Performance of Small Scale Wind Turbines: In Small scale HAWT, much emphasis was given on the factors such as tip speed ratio, rotor speed and pitch angle for a specific aerofoil which affect the performance of wind turbine. There is a big research potential of wind direction effect, wind turbulence intensity and wind gust. It was also reported that variable pitch with VAWT would result with higher power coefficient. A 3-bladed turbine of rotor diameter 2.1 m was tested in a wind tunnel up to a wind speed of 13m/s. At various wind speeds, the values of tip speed ratio (TSR) varied from 2 to 8 and the maximum Coefficient of performance (Cp) of 0.2 occurred at TSR 6. It was also observed that at a particular wind speed, the maximum
power value decreased with the increase in yaw angle (Freere et al., 2010). Singh et al. (2013) observed that the rotor touched the Cp values up to 0.l, 0.217 and 0.255 with the wind speeds of 4, 5 and 6 m/s respectively whereas the baseline 3-bladed rotor targeted 0.052, 0.112 and 0.15 at these wind speeds as shown in Fig. 2. This shows that the two bladed rotors have a better Cp in the low wind speed range of 3 to 7 m/s. At the optimum pitch (β=18°), the two-bladed rotor produced more than double power than the base line rotor. Only at the pitch angle of 15° and at a wind speed of 4 m/s, the power output of the base line rotor coincided with that of the two-bladed rotor.
Fig. 2: Minimum power coefficient of the turbine as a function of wind velocity at different pitch angle (Singh et al., 2013) Design and characterization were studied of a small-scale wind energy portable turbine (SWEPT), of 39.4 cm rotor diameter operating below the wind speed of 5 m/s by Kishore et al, (2013). Maximum coefficient of performance of 14% was obtained at optimal tip speed of 2.9m/s. It had low cut in wind speed of 2.7m/s and which gave 0.83 W of electric power at the rated wind speed of 5m/s. It was also observed that the diffuseraugmented SWEPT of length approximately the same as the turbine's diameter could produce 1.4–1.6 times higher power output than a SWEPT without diffuser. A very small scale, 4-bladed wind turbine have a rotor diameter is 500mm, and having NACA2404 airfoil profile was studied by Hirahara et al. (2005). The results showed that the turbine has a good efficiency in wind speed range of 8–12 m/s with net efficiency and ISBN-978-81-932091-2-7
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power coefficient as 0.25 and 0.36 respectively. It also shows good performance at lower tip speed ratios. The maximum power coefficient was about 0.40 when the tip speed ratio was 2.7. Duquette et al. (2003) had conducted a numerical study and found that increase in power coefficients at lower tip speed ratios was observed with increase in the solidity. Also, the power coefficients increased with the increase in the blade number at a given solidity as shown in Fig. 3. An increase in the solidity from the conventional 5–7% to a range of 15– 25% yielded higher Cp values while lowering tip speed ratio at maximum Cp to 2–4. Due to lower tip speed ratios reduce structural requirements, blade erosion and noise levels.
max. The tunnel blockage effect was small for small TSR, and BF approaches a constant value at a certain TSR, at which point the blades act like a solid wall. It was observed that the tunnel blockage effect and the decay rate of BF are larger for the 12-blade turbine than the 6-blade for the same TSR. It was also determined that no blockage correction is necessary for β=25°, and the blockage correction is less than 5% for BR less than 10% and for TSR less than 1.5.
Fig. 3: Optimum design maximum Cp versus tip-speed ratio for various blade numbers (By Blade element momentum theory analysis) (Duquette et al., 2003)
Fig. 4: Relationships between Cp and TSR under six different β for 12 blades, at U=8 m/s and BR=28.3 % (Chen and Liou, 2011)
A study on small scale HAWT having NACA4415 profile blades was carried out in order to investigate the effects of tunnel blockage on the power coefficient in wind tunnel tests by Chen and Liou (2011). The blockage factor (BF) was determined by measuring the velocities at different points in the wind tunnel and the studies were carried out on a 6-bladed turbine. It was observed that the blockage effects increase as TSR and BF increase, and β decreases. A Relationships between Cp and TSR under six different β for 12 blades, were plotted as shown in Fig. 4 found that smaller the β value, larger the Cp
A small HAWT studied by Mayer et al. (2001) and reported that for a pitch angle of 0°, there is a longer idling period due to the very high angle of attack and the idling period decreased with the increase in blade pitch angle. It was seen that at the pitch angle of 20°, shortest start was obtained.
The AF 300 airfoil was associated with 8 other airfoils designed for low Reynolds application for small horizontal axis wind turbines was studied by Singh et al. (2012). They plotted L/D ratio, CL values at different angles of attack for those 8 airfoils with AF300 as shown in Fig. 5.
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Fig.5: L/D ratio, CL values at different angles of attack plotted for 8 different blades (Singh et al., 2012) For different angles of attack, the forces of lift and drag were calculated and pressure distributions over the surface of the airfoil were obtained. The maximum lift coefficients were obtained at the stall angle of 14°. Flow visualization showed that flow stayed fully attached to the airfoil surface from Re as low as 56,000 at an angle of attack 8° and maintained a fully attached flow up to 14° angle of attack for Re as low as 75,000. A small wind turbine blade using the blade element momentum (BEM) method for a three bladed, Bergey XL 1.0 turbine, with 2.5 m diameter rotor, up wind orientation, rated power of 1000 W at 11m/s wind speed and tip speed ratio of 5.85 and SD 7062 airfoil was made by Song et al. (2014). Blade was tested at the original designed pitch angle and also at 5° and 9° pitch angles. The new blades showed better aero dynamic performance in high speed wind conditions but under low wind speeds, the original blades showed better performance. The original blade was predicted to have higher Cp than the new blades at designed pitch (0°) and tip speed ratio λ less than 4.5, whereas at higher λ the new blades were predicted to have higher Cp values as shown in Fig. 6. The new blades at 5° pitch produced the highest power at wind speeds over 9 m/s, while the new blades at 9° pitch produced less power over all, but performed best at low wind speeds.
Fig. 6: BEM predictions of power coefficient for the new blades at different overall pitch angles, compared to the original Bergey blades (Song et al., 2014) 4. Conclusions: Nevertheless, utility scale wind turbines are serving to harness the wind energy but Smallscale wind turbines can serve a better option for harnessing wind energy due to they are cost effective, easy to manufacture, portable safe and environmental friendly. World is in gesture of switching toward the green energy resources for fulfilling its power needs and research in the field of SWT is one of the milestone in wind energy generation. After going through the reported literature, following substantial conclusions can be drawn: It is observed that unitary scale wind turbine has its impact on the climate of world but it is not clear that the impact on environment due to large scale wind turbine is directly connected or just a correlation. The blade characteristic is a function of wind speed, yaw angle, with and without a nose cone. It also observed that at a particular wind speed, the maximum power value decreases with the increase in yaw angle. At various wind speeds, the values of TSR vary from 2 to 8 and the maximum Cp is 0.2 at a TSR 6. The BEM theory prediction is more accurate for large scale wind turbines than small scale due to Reynolds number and three dimensionality effects (Separation ISBN-978-81-932091-2-7
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delay at the in-board sections radial flow and down wash effect). The two bladed rotors have a better Cp in the low wind speed range of 3 to 7 m/s. At the optimum pitch (β=18°), the two-bladed rotor produces more than double power than the base line rotor. Only at the pitch angle of 15° and at a wind speed of 4m/s, the power output of the base line rotor coincides with that of the two-bladed rotor. Maximum coefficient of performance is 14% obtained at optimal tip speed of 2.9m/s for wind tunnel. The turbine (rotor diameter is 500 mm and 4 bladed) has a good efficiency in wind speed range of 8–12 m/s with net efficiency and power coefficient as 0.25 and 0.36 respectively. It also shows good performance at lower tip speed ratios. The maximum power coefficient was about 0.40 at tip speed ratio 2.7. An increase in the solidity from the conventional 5–7% to a range of 15–25% yielded higher maximum Cp values while lowering tip speed ratio at maximum Cp to 2–4. References: [1]. Chen TY, Liou LR. (2011) Blockage corrections in wind tunnel tests of small horizontal-axis wind turbines. ExpTherm Fluid Sc; 35(3):565–9. [2]. Duquette M.M and Visser KD (2003) , ‘Numerical Implications of solidity and blade number on rotor performance of horizontal scale wind turbines’, Transactions of the ASME , Vol. 125 [3]. Fiedler BH and Bukovsky MS (2011), ‘The effect of a giant wind farm on precipitation in a regional climate model’,
Environmental Research Letters, Vol.6, No.4. [4]. Freere P, Sacher M, Derricott J, Hanson B. A low cost wind turbine and blade performance. Wind Eng2010; 34(3):289– 302. [5]. Hirahara. H, Hossain MZ, Kawahashi M, Nonomura Y (2005), ‘Testing and performance of very small wind turbine’, Renewable energy, Vol.30 pp. 1279-1297 [6]. Kishore R.A, Coudron T, Priya S (2013), ‘Small Scale Wind Energy Portable turbine (SWEPT)’, Journal of wind energy and industrial aerodynamics, Vol.116, pp 23-31. [7]. Mayer C, Bechly ME, Hampsey M, Wood DH. (2001) The starting behavior of a small horizontal-axis wind turbine. RenewEnergy; 22(1):411–7. [8]. Singh RK, Ahmed MR (2013) , ‘Blade design and performance testing of a small wind turbine rotor for low wind speed applications’, Renewable Energy, Vol.50 pp 812-819. [9]. Singh RK, Ahmed MR, Zullah MA, Lee Y-H. (2012) Design of alow Reynolds number airfoil for small horizontal axis wind turbines. RenewEnergy; 42:66–76. [10] Song Qiyue, Lubitz William David. (2014) Design and testing of a new small wind turbine blade. J Sol Energy Eng; 136(3):034502. [11] Tummala A, Velamati R.K, Sinha D.K, Indraja V, HariKrishna V (2016), ‘A review on small scale wind turbines’, Renewable and Sustainable Energy Reviews, Vol.56 pp. 1351-1371. [12] Wang C and Prinn RG (2010), ‘Potential climatic impacts and reliability of very large-scale wind farms’, ‘Atmospheric Chemistry and physics’Vol.10, No.4.
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On-Off Control Based Maximum Power Point Tracking of Wind Turbine Equipped by DFIG Connected To the Grid Rahul Gangwani1*, Om Prakash Bharti2, R. K. Saket3, Shiv Lal4 1,,4 Department of Electrical Engineering, GEC Banswara, Rajasthan, (327001), India 2,3 Indian Institute of Technology (Banaras Hindu University) Varanasi, U.P., (221005), India Corresponding Author: Email: *rahulg.eee15@itbhu.ac.in, +91-7891288020
Abstract: This paper presents An on-off Control method which is based on maximum power point tracking and anticipated to control the rotor side converter of DFIG based wind turbine connected to the grid. The Grid Side Converter is controlled in such a way to assure a smooth DC voltage as well as ensure sinusoidal current on the network. The performance analysis to the new developed DFIG based WT Matlab Simulink model with MPPT based on-off control is assessed with the conventional Matlab Simulink model, which demonstrate the enhanced performance output of newly developed model as compared to the traditional model. Keywords: DFIG; Wind turbine; MATLAB SIMULINK models. Abbreviations: DFIG: Doubly Fed Induction Generator, VSC: Voltage Source Converter, WEC: Wind Energy Conversion. I.
INTRODUCTION The study of increasingly alternate energy sources, requirements for electric energy is growing very fast. Amongst the available alternative energy sources, wind energy, solar energy, plus fuel cells have strained considerable attention. Supplementary, all of these alternate energy sources are also of renewable nature. Among the mentioned alternate energy sources, wind power generation systems have been the most cost competitive alternative. For the first decade of the 21st century, India emerged as the 2nd leading wind power market in Asia. More than 2,100 MW wind capacity projects were added in the financial year 2010–11. The installed capacity increased from a modest base of 41.3 MW in 1992 to reach 28,700 MW by December 2016. Because the route, as well as the speed of winds, may differ from position to position as well as occasionally, the variable speed wind turbine technology offers inherent advantages over the fixed rate one [1].The DFIG is worn in cycle with the wind turbine to produce electric energy. The DFIG through the use of the two back to Back converters, rotor side and grid side converters can deal with a wide variety of wind speeds by injecting a compensating variable frequency current component in the rotor circuit. Its facilitates both super and subsynchronous operations of DFIG. It is well known that the Induction machine is widely used in industrial application due to its low cost, the simplicity of construction and low maintenance cost. Such type of mechanisms can be used for an electric
production wherever the momentum of the prime mover is steady, i.e., just above the synchronous speed. On the other hand, it is a fact that the wind speed varies drastically depending upon the environmental conditions and time of operation. Thus, there is a significant margin of speed variation. Such large margins of speed variation make wound rotor induction machines suitable for generation of wind energy [2]. In addition to its significant speed variation, the wound rotor induction machine offers the additional benefit of bidirectional move of the rotor power which depends on the rotor speed and field speed [3]. The DFIG is fundamentally a wound rotor induction machine capable of operating in super synchronous as well as subsynchronous mode. The compensation of DFIG more than the permanent speed induction generators is enhanced power excellence, concentrated mechanical stress as well as fluctuation and advanced energy capture [4].The operations of DFIG associated with the grid are helped with the help of rotor side and grid side converter. It is the accountability of the inverter connected to the rotor side to provide the necessary complementary frequency to uphold the stator frequency at a constant level, in spite of variations in the mechanical power. The control of DFIG presents a twofold crisis to compensate the speed variations and reactive power. The stability and presentation of the overall setup are to be preserved in the face of model uncertainties, external noise, a variety of the internal machine parameters and speed. The primary question for the research to carry forward is the ways by which ISBN-978-81-932091-2-7
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the available energy at a given wind velocity can be harnessed to its maximum.
II.AN OVERVIEW OF WIND TURBINES A wind turbine is a mechanism that converts kinetic energy as of the wind into mechanical energy. If the mechanical energy is used to create electrical energy, the machine may be named a wind generator or wind changer. If the mechanical energy is wont to drive machines, for example to grinding grain or pumping water, the device is predicted a windmill or wind pump. Today's wind turbines are manufactured in a range of vertical and horizontal axis types. Wind turbine system can be categorized by the nature of their operation, i.e., either fixed speed or different speed. For fixed-speed wind turbines, induction generator is straight linked to the grid. For the reason that the speed is approximately set to the grid frequency and most probably not controllable. It is not probable to store the turbulence of the wind in the form of energy rotational. In favor of a variable-speed wind turbine, the generator is controlled by power electronic apparatus, which makes it probable to control the rotor speed. The power variations caused by wind variations can be more or less engrossed through changing the rotor speed, and thus power variation originating from the wind conversion and the drive train can be reduced. Hence, the power quality impact caused by the wind turbine can be improved compared to a fixed-speed turbine.
the wound rotor induction machine, which is shown in Figure 1(b). This type of generator can be defined as a fraction (~30%) of the rated power. But the system ensures competent power conversion appropriate to variable rotor speed, which adjusts automatically by prevailing wind speeds [5]. The primary benefit of doubly-fed induction generators, while used in wind turbines, is that they permit the amplitude as well as the frequency of their output voltages to be maintained at a constant value, despite what the speed of the wind blowing on the wind turbine rotor is. As doubly-fed induction generators frankly associated with the AC power network and stay at the back coordinated at all times with AC power network. Further compensation includes the capability to control the power factor (e.g., to uphold the power factor at unity) while keeping the power electronics devices in the wind turbine at a moderate size. In the subsynchronous operating mode, the stator of the DFIG supplies power to the grid. In the super-synchronous operating mode, both stator output power and the rotor slip power are fed into the grid. A variable speed wind turbine with full-size converter along with doubly fed induction generator is exposed in Figure 1. However, the converter has to be intended for the rated power of the turbine. This problem can be taken care of by using the DFIG, which has a converter connected to the rotor winding of the wound rotor induction machine (Figure 1(b)). Rated power has been reduced to (25% - 35%) in the case of DFIG. The main components of the wind turbine are given as follows.
A. Primary observation of the DFIG Based Wind Turbine The mechanical power which is produced by a wind turbine is proportional to the cube of the wind speed, i.e., Pm â&#x2C6;&#x17E; v3. Here Pm is the mechanical power of the wind, as well as v, is the velocity of the wind speed. The maximum power which is received through the revolving speed of the wind turbine defer from different wind speeds. For this reason, the operation of variable speed is necessary to maximize the energy. Two fundamental concepts exist for variable speed turbines. The first ideas are an electric generator with a converter connected to the stator windings along with the grid network which is shown in Figure 1(a). For the rated power of the wind turbine, the converter is to be designed. A generator is a synchronous machine which is frequently a permanent magnet. On behalf of the direct drive concept, a wind turbine using a DFIG has a converter associated to the rotor windings of
(a)
(b) Fig. 1. Variable speed wind turbines (a) with full-size converter (b) with a DFIG[3] (i) Drive Train along with Aerodynamics: The drivetrain has a turbine, gearbox, shafts and other mechanical components of the wind turbine; a multi-mass (in general two mass) model to be used for dynamic studies of wind turbines through DFIG [6]. A simplify aerodynamic model is sufficient when the speed and pitch angle changes ISBN-978-81-932091-2-7
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on the aerodynamic power during the grid faults. For stability investigation, the drive train system has to be approximated by the at least a two massspring as well as damper model while the system response to massive disturbance [7]. There is a flexible shaft during the turbine, and generator masses are associated. (ii)Pitch Angle Control System: The “Pitch Control” is a technique to mechanically regulate the blade pitch angle to change the curve of the power coefficient to the turbine [8]. PI control is used to realize the pitch angle, in servomechanism model using time control Tservo, accounts for the realistic response in the pitch angle control System. For the period of the grid faults how quick the aerodynamic power can be reduced to stop more speed is determined by the velocity of altering limit. B.Modeling of the Wind Turbine Here wind turbine model is discussed for optimal operations of the wind turbine at different wind speeds [9,18]. It has to operate at its maximum power coefficient (CPoptimum=0.3-0.5), i.e., at a constant tip speed ratio, proposed for operation approximately it's maximum power coefficient. The aerodynamic power generated by a wind turbine is given as follows.
Pwindturbine Pair 1 Pm Ar v3C p , 2
Cp
A=Swept area of the blades (=πR2), Tip ratio speed, v = wind velocity T rotating speed of the rotor, = Pitch angle, R= Radius of the area covered through the blades Cp = wind turbine energy coefficient.
III. AN GENERAL IDEA OF THE DFIG OPERATING PRINCIPLE The overview and operating principle of DFIG discussed in this section is also mentioned in [10, 18]. The structural diagram of DFIG with converters is shown in Figure 2. The AC/DC/AC converter comprises two components: the rotor side converter Crotor as well as network area converter Cgrid. These converters are voltage source converters that utilize forced commutation power electronic devices (IGBTS) to synthesize
AC voltage from DC voltage source. A capacitor connected to DC side acts as a DC voltage source. The generator slip rings are linked to the rotor side converter, which shares a DC link with the grid side converter in a so-called back-to-back configuration. The wind power captured by the turbine is converted into electric power by the IG and is transferred to the network using stator as well as rotor windings. The control system affords the pitch angle command, along with the voltage commands for Crotor as well as Cgrid to control the power of the wind turbine, DC bus voltage plus reactive power or voltage at grid terminals. [11]. When the rotor speed is higher than the rotating magnetic field from the stator, the stator induces a high current in the rotor. The quicker the rotor rotates, the extra power will be transfer as an electromagnetic force to the stator, furthermore, in turn, converted to electricity that is feed to the electric network. The velocity of the asynchronous generator will differ with rotating force functional to it. Its dissimilarity from synchronous speed in percent is called generator’s slip. With rotor winding short-circuited, the generator at full load is only a small percentage. Using the DFIG, slip control provides the rotor plus grid side converters. At high rotor speeds, the slip power is recovered and delivered to the network, resultant in high overall system efficiency. If the rotor speed range is determined, the ratings of the frequency converters will be small equated with the generator rating, which helps in reducing converter losses and the system cost [12].Because the mechanical torque functional to the rotor is constructive for power production and since the rotation speed of the magnetic flux in the air gap of the generator is definite in addition to constant for an invariable frequency network voltage, the sign of the rotor electric power output is a function of the slip sign. Crotor, as well as Cgrid, have the capability of generating or absorbing reactive power can be employed intended for controlling the reactive power or the grid terminal voltage. The pitch angle is controlled to limit the generator output power to its standard value in support of high wind speeds. The grid provides the necessary reactive power to the generator.
IV.MPPT CONTROLLER Maximum power point tracking is an efficient method of extracting generated power from the generating systems used by grid-connected ISBN-978-81-932091-2-7
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inverters, solar battery chargers, and wind energy conversion system. Wind energy is dependent on weather, topology, and environment. It is essential to choose the best place where the quality of air can produce more electricity. Then it is difficult to wind turbine to provide 60% of power wind speed. Wind energy conversion system also has other losses like mechanical friction as well as low generator`s efficiency. So the amount of power output from WECS depends on the tracked wind power. Therefore, a maximum power point tracking control is required [13].
ratio error) with guaranteed properties of attractiveness and stability. An on-off Control method based maximum power point tracking is planned to manage the rotor side converter of wind turbine equipped with doubly fed induction generator connected to the grid. A. Controller Design This approach supposes that the WECS reacts sufficiently fast to the variation of the lowfrequency wind speed; this happens in the case of low-power WECS. Thus, for ensuring the optimal energy conversion, it is sufficient to feed the electrical generator with the torque control value corresponding to the steady-state operating point placed on the ORC. To this end, an on-offcontroller-based structure can be used to zero the difference opt , where is given by the low-frequency component of the wind speed, v: [17]
r R v
B. Rotor side converter based On-Off control: Fig. 2.Basic diagram of Doubly Fed Induction generator with converters [18]
V. ON-OFF CONTROL Several research works have been presented with different power/voltage control of the DFIG based wind energy conversion system associated to the grid with battery storage. These control diagrams are usually based on vector control notion with conventional PI controllers due to their simplicity and easy implementation [14] [15]. Fuzzy logic and adaptive fuzzy controllers have also been used in the power/voltage control loop [16]. The Classical controllers for wind energy conversion systems (WECS) can be developed for more effective strategies based on intelligent control technique. On-Off control is a robust control scheme aiming at captured power maximization of DFIG-based WECS connected to the grid with battery storage. This technique superposes the tracking of the optimal torque value [17].The control objective can be formulated as an optimization problem, in which an objective function is maximized or minimized, to extract the maximum power from the wind energy. There is a specific complexity concerning the On-Off control, concerning the description of a switched constituent (following the sign of the tip speed
For ensuring the maximum power point tracking an On-Off supposes that the WECS reacts sufficiently fast to the variation of wind speed (see Fig. 3). An On-Off controller can be used to zero the difference between the optimal tip speed ratio and the actual tip speed ratio [19]:
opt
The on-off objective is to make the difference between the optimal tip speed ration and the exact tip speed ratio as small as possible with regulating the rotor speed according to the wind speed. The control law u has two components: Temref = ueq + un Where the equivalents control ueq as defined: ueq = 0.5π R 3
C p (opt ) iopt
With: A = 0.5π R 3
vs2 = Avs2
C p (opt ) iopt
and i is the
gearbox ratio, un is an alternate, high-frequency component, which switches between two values, α and +α, α>0: un = α sign ( ) Component ueq makes the system operated at the optimal point, whereas un has the role of stabilizing the system behavior around this point, once reached. The control law associated with the ISBN-978-81-932091-2-7
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diagram in Fig.3 provides the steady state torque reference. The control input has, in this case, a large spectrum; the zero-order sample-and-hold (S&H in Fig.3) has been introduced to limit the loop switching frequency. If this frequency is too large, the control loop becomes inefficient. The zero order S&H element is approximated as a first order low-pass filter with a time constant TS&H = Ts/2, where Ts is the sampling period of the S&H. In Fig.3 the nonlinear part consists of an On-Off relay (“sign” block).The control of the rotor side converter is illustrated in Fig.3; the reference i qref is derived from the high-speed shaft Ωh and measured wind speed v by tuning the On-Off controller based maximum power point tracking (MPPT). Thus, by adding a PI regulator in the loop control of the d-axis and q-axis rotor currents is realized, as shown inFig.3 [19].
voltage of the DC bus capacitor. For the grid-side controller, the d-axis of the rotating reference frame used for d-q transformation is aligned with the positive sequence of the grid voltage. This controller consists of measuring the d-q components of AC currents to be controlled as well as the DC voltage. Elsewhere the DC/DC buck-boost bidirectional converter controlled voltage source. This converter maintains constant dc-link voltage as a reference value during discharge/charge current from/to batteries bank. [19]
Fig. 4: Direct bus control scheme [19] The output of the DC voltage regulator is the current reference Idgc_ref for the current regulator. The current corrector controls the magnitude and phase of the voltage generated by the converter Cgrid (Vgc). The grid side controller is presented in Fig. 5.
Fig.3.Rotor side converter based on-off control scheme [19] C: Inverter and direct bus voltage control: The direct bus voltage is given by the following equation [19].
1 Vdc I c dt c With: Ic = Idc – In With Vdc and Idc are the direct bus voltage and current respectively and In is the three-phase currents supplied to the grid. The control scheme of the direct bus voltage is presented in Fig. 4. The grid-side converter is wont to regulate the
Fig. 5: Grid side control scheme [19]
VI. SIMULATION AND RESPONSE OF THE DFIG SYSTEM Figure 6 represents the detailed doubly fed induction generator Matlab diagram and voltage (Pu) at DFIG terminals presented in Figure 7. Furthermore, Figure 8 shows the active power delivered. The reactive power requirement of the DFIG is presented in Figure 9. DC link voltage (Pu) at the conventional link capacitor of DFIG is presented in Figure 10. ISBN-978-81-932091-2-7
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Fig. 9(b): Reactive Power Q v/s time from conventional model Fig. 6.Detailed DFIG wind turbine diagram
Fig.10 (a). DC link voltage Fig. 7.Voltages at the DFIG terminals
Fig.10 (b). DC bus link voltage Vs. time from conventional model ACKNOWLEDGMENT Fig. 8(a).Active power delivered
Fig.8 (b). Active Power P Vs. time from Conventional model
The authors acknowledge the partial financial support from the Indian Institute of Technology (Banaras Hindu University), Varanasi (U.P.) India for carrying out this work. Appendix: Simulation Data Table 1: DFIG parameters Parameters Power Stator resistance Rs Rotor resistance Rr Stator phase inductance Ls Rotor phase inductance Lr Generator inertia J Friction factor f
Values 1.5 MW 0.023 Ω 0.016 Ω 0.18 H 0.16 H 0.0685 kg m2 0.01 N ms
VII.CONCLUSION
Fig. 9(a).Reactive power requirement of the DFIG
The concept of MPPT has been proposed here to achieve the goal of tracking maximum power at a given wind velocity. To accomplish the MPPT from the wind system, the MPPT block in coordination with the rotor control block acts to maintain the torque to the value that is optimum for extracting the maximum power output from it. The energy conversion device which is used in ISBN-978-81-932091-2-7
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wind turbine systems is Doubly Fed Induction Generator. Therefore, a doubly fed induction generator was modeled as an energy conversion device. The modeling included the verification of developed model with that of the generator present in the library of the MATLAB/ Simulink. The results were better than of the model in the MATLAB library. Further to achieve a double-fed induction generator the modeled generator was incorporated with rotor side converters and controllers. The results obtained showed that the system could perform well at average wind speeds while the results were inconsistent with that of expected values at lower and higher wind speeds.
REFERENCES: [1] “Global Wind Statistics 2016”, Global Wind Energy Council, February 2017. [2] “Indian wind energy outlook 2012”, Global wind Energy council, November 2012. [3] Om Prakash Bharti, R.K. Saket, S.K. Nagar,”Controller design for DFIG driven by Variable speed Wind turbine using static output feedback technique,” Engineering, Technology & Applied Science Research, Vol. 6, No. 4, 2016. [4] Lee, C, “Fuzzy-logic in control-systems: Fuzzy logic controller, Part I,” IEEE Trans Syst Man Cybern, 1990. [5] Shabani, A. Deihimi, “A New Method of Maximum Power Point Tracking for DFIG Based Wind Turbine,” 25th International Power System Conference, 2010. [6] Abram, Perdana, “Dynamic Models of Wind Turbines,” Chalmers University of Technology/Ph.D. Thesis, Goteborg, Sweden, 2008. [7] Andreas, Petersson, Stefan Lundberg, “Energy Efficiency Comparison of Electrical Systems for Wind Turbines,” Chalmers University of Technology. [8] Ake Larsson, “The Power Quality of Wind Turbines,” Chalmers University of Technology/Ph.D. Thesis, Goteborg, Sweden, 2000. [9] S. Masoud Barakati, “Modeling and Controller Design of a Wind Energy Conversion System Including a Matrix Converter,” University of Waterloo/Ph.D. Thesis, 2008. [10] O. P Bharti, R.K Saket, S. K Nagar, “Reliability Analysis of DFIG Based Wind Energy Conversion System,” ‘ICCAE 17’, February 18-21, 2017, Sydney, Australia. [11] Hsing Chen Chiung, Hong Chih-Ming, Cheng FuSheng. Intelligent speed sensorless maximum power point tracking control for wind generation system. Int J Electr Power Energy Syst 2012.
[12] Munteanu I, Bratcu AI, Cutululis NA, Ceang E. “Optimal control of wind energy systems: towards a global approach,” Springer; 2008. [13] Ackerman T. “Wind power in power systems,” Chichester, UK: John Wiley & Sons; 2005. [14] Blaabjerg F, Teodorescu R, Liserre M, Timbus AV. “Overview of control and grid synchronization for distributed power generation systems.” IEEE Trans Ind Electron 2006. [15] Munteanu I, “Contributions to the optimal control of wind energy conversion systems,” Ph.D. Thesis. Galati, Romania: “Dunarea de Jos” University of Galati; 2006. [16] Om Prakash Bharti, R. K. Saket, S.K. Nagar, “Controller Design of DFIG Based Wind Turbine by Using Evolutionary Soft Computational Techniques,” Engineering, Technology & Applied Science Research, Vol. 7, No. 3, 2017, 1732-1736. [17] Z. Wang, Y. Sun, G. Li, and B.T. Ooi, “Magnitude and frequency control of grid-connected doubly fed induction generator based on a synchronized model for wind power generation,” IET Renewable Power Generation, 2010. [18] Om Prakash Bharti, R. K. Saket, S.K. Nagar, “Controller Design for Doubly Fed Induction Generator Using Particle Swarm Optimization Technique,” Renewable Energy, Science Direct, Elsevier 114 (Part B), 2017, 13941406. [19] Sami Kahla, Youcef Soufi, Moussa Sedraoui, Mohcene Bechouat, “On-Off control based particle swarm optimization for maximum power point tracking of wind turbine equipped by DFIG connected to the grid with energy storage,” International Journal of Hydrogen Energy, Volume 40, Issue 39, 2015.
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Advances in Green Composites: A Review Ranjan Kumar Singh, Moti Lal Rinawa, Manoj Mittal Engineering College Jhalawar, Rajasthan, India Corresponding author: ranjankumar@live.com
1Government
Abstract: The inevitable decrease in the supply of petroleum-based resources significantly restricts the sustainable development of wood adhesive industry. Thus, more and more attention has been focused on the utilization of renewable materials. This paper reviews the properties of various natural and the modification of technical fibers and resins for improving the performance of the natural-based wood adhesives. 1. Introduction Green composites can be defined as a biocomposite reinforced by natural fibers with biodegradable matrices. The green composites are degradable and have sustainable properties, which can simply dispose without harming the environment. Weathering causes degradation of polymer composite through photo-radiation, thermal degradation, photo-oxidation and hydrolysis. These processes result in changes in their chemical, physical and mechanical properties. The development of green composites promotes the use of environmentally friendly materials. The use of green materials provides alternative way to solve the problems associated with agriculture residues. Currently numerous research groups are dedicated to minimising the environmental impact of polymer composite production, where the polymer matrices are derived from renewable resources such as polylactide (PLA), thermoplastic starch (TPS) or thermoset matrices. Their high renewable content derives from vegetable oils and, combined with natural reinforced fibers (NF) to form environmentfriendly and fully degradable composite laminates, they represent a potential substitute for petroleum-based resins. 1.1 Ecobased Matrices The wood-based polymer matrices availability is nowadays very poor, but it rapidly grows as more studies are done and more useful informationâ&#x20AC;&#x2122;s are given. The different kinds of bio based natural polymer matrices used are listed below: Thermoset matrices: polyols are compounds with multiple hydroxyl functional groups available for organic reactions, and they react with a large
number of chemical species, called curatives or hardeners, to produce cross-linked thermoset matrices. The most important oil used in polyols production is soy bean oil, but also cashew nut oil could give the same results. In order to decrease the impact of its activity on global warming, polyols can be also combined with petroleum-based chemicals. Thermoplastic matrices: the most commercially available plastic matrix is the cellulose one, which is properly toughened thus it is considered a 100% bio-based matrix. Starch based polymers and Poly (lactic acid) PLA are both available: the employment of the first ones depends on the ability to reduce their moisture absorption, while the second one has similar properties to polystyrene. Summing up, the employment of these bio-based polymers depends on the possibility to modify their properties in order to obtain an easier processing and improve toughness in the final green composites. 1.2 Natural Fibers
Natural fibers can be defined as bio-based fibers or fibers from vegetable and animal origin. This definition includes all natural cellulosic fibers (cotton, jute, sisal, coir, flax, hemp, abaca, ramie, etc.) and protein based fibers such as wool and silk. Excluded here are mineral fibers such as asbestos that occur naturally but are not biobased. Asbestos containing products are not considered sustainable due to the well-known health risk that resulted in prohibition of its use in many countries. On the other hand, there are manmade cellulose fibers (e.g. viscose-rayon and cellulose acetate) that are produced with chemical procedures from pulped wood or other sources (cotton, bamboo). Similarly, regenerated (soybean) protein, polymer fiber (bio-polyester, ISBN-978-81-932091-2-7
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PHA, PLA) and chitosan fiber are examples of semi-synthetic products that are based on renewable resources. In this paper also, the use of fiber in food industries is excluded, where in recent years these are frequently promoted as dietary fibers or as supplements for health products. 1.3 Hybridization
The hybrid systems for improved material or structural performances is a well-known concept in engineering design. A recent work has shown that the properties of hybrid natural/glass composite loading have been found to be an effective way to improve composite's mechanical properties and dimensional stability (moisture, temperature, etc.). The stiffness or mechanical properties of green composites can thus be overcome by structural alignments that replace material in specific positions for higher structural performances. 2. Tables In the table below, Table.1, a physical and mechanical properties comparison between natural and synthetic fibers is shown. As noted, natural fibers have lower density values and they fit perfectly for non-structural uses. In these terms, natural fibers can replace synthetic ones [1] obtaining even more efficient results. Table 1. Fibres’ mechanical properties PROPERTI ES FIBERS
DENSITY (g/cm^3) TENSILE STRENGTH (MPa)
TENSIL E MODUL US (GPa)
JUTE
1.3-1.45
393-773
13-26.5
1.16-1.5
FLAX
1.50
345-1100
27.6-80.0
2.7-3.2
HEMP
-
690
-
0.6
BASALT
2.65-2.80
4000-4700
84-87
3.15
SISAL
1.45
468-640
9.4-22.0
3-7
E-GLASS
2.5
2000-3500
70
2.5
ARAMID
1.4
3000-3150
63-67
3.3-3.7
CARBON
1.7
4000
230-240
1.4-1.8
STRAIN (%)
3. Processing and processability Literature data on green composites show a clear prevalence of wood end natural fibers in combination with eco matrices like bio based natural oils: this influences the information available on processing and processability. Typical processing techniques include extrusion followed by injection or compression molding. During the processing, temperature must not exceed 200°C and the retention time of the material exposed to high temperatures should not be too long in order to avoid fibers' enervation. Very common technologies for NF composite materials are resin transfer molding, vacuum injection molding, structural reacting injection molding, injection molding and compression molding.
4.
Future Research Directions
New environmental regulations and changing governmental attitudes have stimulated the research of new products and processes environmental friendly. Natural fiber reinforced wood based biodegradable polymer composites appear to have a bright future for a wide range of applications. These green composite materials with various interesting properties may soon compete with the existing fossil plastic materials.
References
Natural fiber reinforced biodegradable polymer composites, J. Sahari, S.M. Sapuan, Rev.Adv.Mater.Sci. 30 (2011) 166-174 [2] Natural Fiber Eco-Composites G. BogoevaGaceva, M. Avella, et alt., M.E. Errico, POLYM. COMPOS., 28:98–107, 2007. [3] Use of Eco-Friendly Epoxy Resins From Renewable Resources as Potential Substitutes of Petrochemical Epoxy Resins for Ambient Cured Composites With Flax Reinforcements. D. Bertomeu, D. GarciaSanoguera, O. Fenollar, T. Boronat, R. Balart. POLYM. COMPOS., 33:683–692, 2012.
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Nonlinear coupling of Inertial Alfvén waves and cavity formation in low beta plasmas Moti Lal Rinawa Govt. Engineering College Jhalawar-326023 (India) Corresponding Author : motilal.rinawa@gmail.com ABSTRACT In the present paper, we have investigated nonlinear interaction of 3D- inertial Alfvén wave (3DIAW) and perpendicularly propagating magnetosonic wave for low -plasma = me / mi like auroral regions. We have developed the set of dimensionless equations in presence of ponderomotive nonlinearity due to 3D-IAW in the dynamics of perpendicular magnetosonic wave. Stability analysis and numerical simulation has been carried out to study the effect of nonlinear coupling between waves which results in formation of localized structure and density cavity, applicable to low beta plasmas like auroral region. The result reveals that localized structure and density cavity becomes more and more complex with time. From the obtained result, we observed the density fluctuations of ∼0.1n0, consistent with the FAST spacecraft observation of inertial Alfven waves in the dayside aurora reported by Chaston et al. [2000]. Keywords – Auroral region, cavitation, Inertial Alfvén wave
1.
Introduction
Alfvén waves (AWs) are ubiquitous in space plasmas1. These were discovered for the first time theoretically by Hannes Alfvén in 1942, experimentally by Lundquist3 and observed by Chaston et al. [2000]. Nonlinear waves and chaos (NWC) are assumed to play vital roles in the heating and acceleration of charged particles [Goertz ,1984; Shukla et al.,1998; Seyler and Liu, 2007], wave-wave / waveparticle interactions [ Hasegawa and Chen, 1976; Shukla et al, 2007]. The main objective of this paper is to evaluate nonlinear coupling of 3D-IAW with PMSW to study the density cavities and formation of localized structure applicable to solar corona and auroral region (Earth’s ionosphere). For this purpose, using bi-fluid approach the coupled dynamics of 3D-IAW and PMSW in the presence of ponderomotive force has been developed. The linear growth rate of the modulational instability (M.I.) has been obtained and then numerical simulation results have been carried out to study the nonlinear stage of this instability. The paper is further organized as follows: dynamics of PMSW and 3D-IAW is presented in section-2 and 3 respectively. Stability analysis and numerical
simulation results are presented in section-4 and 5 respectively. Results are discussed in section-6 and finally, the last section comprises of the conclusion. 1. Dynamics of Inertial Alfvén Wave Let us consider the dynamics of 3D-IAW. The ambient magnetic field is along the z axis. r i.e. B0 B0 zˆ , where B0 is the background magnetic field. The wave is assumed to be propagating in the x y z plane i.e. r k k0 r rˆ k z zˆ . Therefore, the dynamical equation for 3D-IAW can be obtained as follows, The perpendicular components of electron and ion fluid velocities for low - plasma = me / mi are given as
e
n c c e k B Te zˆ e1 zˆ B0 B0 e n0
(1) 2 2 2 ci i t
cci0 cci2 Ti Ti zˆ ni1 i ni1 B0 en0 B0 en0
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The parallel component of electron fluid velocity is e z
eE z i 0 m e
(3) Furthermore, the (insignificant) Parallel ion fluid velocity in the 3D-IAW field is iz ieEz / mi .Taking parallel component of Ampere’s law, Jz
is the pe electron inertial length. Equation (8) gives the dispersion relation as follows,
02 2
VA k0z
e z t c
Where
2
n%e A%z 1 n0 t 2
2 2
(5) Where n0 is the unperturbed plasma number density and n% e is the number density change due to the presence of magnetosonic wave, pe is the electron plasma frequency and c is the velocity of light. Making use of current density r r .J 0 and substituting the value of z from
equation (5) leads to V 2 n% A%z 2 A 2 ci 2 1 e 2 t c ci t n0 z (6) Taking a time derivative of Faraday’s law, 2 Az 2 z 2 t 2
c
2
t
c
tz
(7) Taking a derivative of equation (5) with respect to ' r ' and derivative of equation (6) with respect to z and substituting in equation (7), one can get the dynamical equation for 3DIA 2 A%z 2 2 A%z V 2 2 n 2 A%z e2 A 2 ci 2 1 2 2 2 t t ci t n0 z 2
1
1
2 e
k0r 2 i2 k0 z2
(9)
c 2 Az 4
(4) Taking a time derivative of equation (4) and substituting the value of current density, J z using equation (3) and taking a perturbation in density as ne n0 n%, one can get the e equation of electric field along the magnetic field, z as below,
c
e
n n%e n%and i
Where
i
c
pi
is an ion inertial
length. The term i k 0 z 2
appears due to the finite
2
in equation (9)
0 . ci
Considering plane wave solution of equation (8) as follows,
A%z
A z ( x , y, z , , t ) e
i ( k 0 r rˆ k 0 z zˆ 0 t )
(10) Using equation (10) in equation (8), following equation has been obtained for the case, when z Az = k 0 z Az , i
201e2k0r2 Az VA2k0z21 t
i2k0r
02e2 Az 02e2 2Az 2 Az n i Az 0 VA2k0z21 r VA2k0z21 r2 k0z z n0
(11) 2 2 0 2 VA k0 z , k0r ( k0z ) is the , 2 2 ci ci component of the wave vector perpendicular (parallel) to B0 zˆ and 0 is the frequency of the 3D-IAW.
Where
2. Dynamics of Magnetosonic Wave Assuming the dynamics of low frequency PMSW propagating along the x axis and r polarized in ‘y’ direction i.e. k k x xˆ and r E Eyˆ .The background magnetic field is r along the z axis i.e. B0 B0 zˆ , where B0 is the ambient magnetic field. The dynamical equation for PMSW is as follows (i) The equation of motion :
(8)
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And
r v j
r qj r qj r j kT j r n j r E ( v j B0 ) Fj t mj cm j mj n0 , (11) (ii) The continuity equation: n r r .( nv ) 0 , t (12) (iii) Faraday’s law: r r r 1 B ( E ) , c t (13) r where v j is the velocity of species j = i, e (i =
ions, e = electrons), mj and Tj are the masses and temperature of ions and electrons respectively, c is speed of light in vacuum and r r r r qj r r F j [ m j ( j .) j ( j B0 )] is the c ponderomotive force due to 3D-IAW. Putting r the values of v j in wave equation and taking ' y ' component of that, one can have 2 Ey x 2
2 2 1 E y 1 E y 4 n0Te 2 ne c 2 t 2 VA2 t 2 cB0 xt n0
4 n0e F jx 2 F jy 2 c icj m j icj2 m j
(14) The electron continuity equation yields ne cE y . t n0 x B0 (15) Components of ponderomotive force are given as Fex o B0
2
me (1 ) 2 kr20 mi (1 ) kr20 Az 2k z20 8 (1 )k z20 x 4
2
Fiy
mi o (1 )2 kr20 2i 0 Az 1 4 B0 2(1 ) 2 k z20 1 ci x
(17) Substituting Eqs. (15), (16) and (17) into Eq. (14), one obtains 2 1 2 ne 1 2 2 2 x VA t n0
1 2 k 2 0r 4VA 2 B0 2 2k02z
02
1 m k 2 1
2
2
02 2 2 , k0r e 2 ci
, Equation (18) represents the dynamical equation of PMSW ( = ci ) whose righthand side represents ponderomotive force due to 3D-IAW. Equation (18), after normalization, and equation (8) can be written in dimensionless form as Az Az 2 Az Az i 1 2 i n Az 0 t r r 2 z
(19) and
2
2 2 n 2 t 2 x
2
2
(1 )2 (1 )kr20 2 Az , 2 2 (1 ) k x z0
2
2
A
x
z
2
(20)
2
02
V A 2 k 0 r 2 e 2 k 0 z 2 1
. The normalising
are xn e , zn
parameters tn
20 2 , VA 2 k0 z 2 k0 r e 1
1
And
2
2 0r 2 0z
Cs , and 0 , Az are 2 VA the frequency and perpendicular magnetic field of the 3D-IAW, respectively. VA ( B02 4 n0 mi )1 2 is the Alfvén speed,
where n ne ni ,
Where
m Fix i o 4 B0
mi
(18)
i
, m (1 )2 kr20 Fey e 0 Az 4 B0 2 k z20 x (16)
2 Az k x 2
e
2 0 1 e 2 k 0 r 2 2
V A k0z
2
1
,
1 2k0 r e 2 k0 z 2
,
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For k0 r e 0.035 and 0 / ci 0.75 , one can
nn k 0 r 2 e 2 n0 and B
n
2 0
1
4 k 0 r 2 e 2V 2
2 k 02 z
k 02 r
2 A
1
1 2 1
me mi
k 2 02 r k0z
k0r 4.66 106 cm1 , k0 z 3.52 106 cm1 and 0 2.16 103 sec1
calculate
1 2
B0
By considering adiabatic response of equation (20), we get 2 n Az (22) Combining equation (22) into equation (20), we get the following equation A A 2 Az A 2 i z i1 z 2 i z Az Az 0 2 t r r z (23) 3. Numerical Simulation We have performed the numerical simulation of equations (23) using 2D pseudo-spectral method in a 2 r 2 z periodic spatial domain with wave numbers of perturbation, r , z =0.2 (normalized by xn1 and zn1 respectively) and (256 256) grid points. The initial conditions of simulation are Az r, z,0 Az 0 1 0.1cos r r 1 0.1cos z z (26) Where Az 0 = 0.5 is the amplitude of the homogenous pump 3D-IAW. A finite difference with predictor-corrector method was utilized for the evolution in time with step size of dt 5 10 5 . To solve system of dimensionless equation (23), we have studied the algorithm for the well-known modified nonlinear Schrödinger (NLS) equation. The accuracy was determined by consistency of the 2 number N Azk in the case of NLS
. The normalising parameter values are
xn 2.74108 cmz , n 1.16108 cmt , n 0.296sec,nn 24.5cm3 and Bn 0.037 G . 4. Results and Discussion In Sec. 4, we have presented the stability analysis of dimensionless equation (23) and obtained equation (25). Next, figure (3) represents 3D evolution of density profile in the r– z plane at the same time as in case of localized structures for auroral region. From the figures (3), one can observe that density dips are form x = 2.43, z = 2.57 (figure (3(a))), but as time increases, density dips becomes intense and more complex in nature. The magnetic field is trapped in the regions of low density due to the ponderomotive nonlinearity. Small-scale length density cavities have been observed in the auroral zone by Viking and Freja spacecraft [Wahlund et. al, 1994; Chaston et. al., 1999]. For the auroral region, we observed the density fluctuations of ∼0.1n0, consistent with the FAST observation reported by Chaston et al. [2000].
References 1. Alfvén, H. (1942), Existence of electromagnetic hydromagnetic waves, Nature (London), 150, 405. 2. Benson, R. F. (1985), Auroral kilometric radiation:Wave modes, harmonics, and source region electron density structures, J. Geophys. Res., 90(A3), 2753– 2784. k 3. Benson, R. F., W. Calvert, and D. M. equation. Klumpar (1980), Simultaneous wave The values of 1 and 2 can be estimated from and particle observations in the auroral kilometric radiation source region, the low- plasma parameters. For application Geophys. Res. Lett., 7(11), 959– 962. purpose in low- plasma , the typical 4. Brodin, G. and L. Stenflo (1990), parameters for auroral altitude of 1700 km Coupling coefficients for ion-158 [Wu, Huang and Wang, 1996] are as follows: cyclotron Alfvén waves, Contrib. 3 3 B0 0.3G, n0 5 10 cm , Te 1.16 104 K . Plasma Phys., 30, 413-419. Using these parameters, one can find: 5. Champeaux, S., A. Gazol, T. Passot, and 8 VA 9.25 10 cm / s, P. L. Sulem, (1999), in proceedings of 7 3 3 1 5 workshop 9.810 cm/s. on nonlinear MHD Waves Vte 4.210 cm/s,e 7.5210 cm,ci 2.8710 sec , S 341.45cm,Cs the and Turbulence, Nice, France, 1-4 Dec. ISBN-978-81-932091-2-7
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6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
1998, edited by T. Passot and P. L. Sulem (Springer, Heidelberg), pp. 55-82. Dastgeer, D. and P. K. Shukla (2009), 3D simulations of fluctuation spectra of the Hall-MHD plasma, Phys. Rev. Lett., 102, 045004. Ergun, R. E., et al. (1998), FAST satellite observations of electric field structures in the auroral zone, Geophys. Res. Lett., 25(12), 2025–2028, doi: 10.1029/98GL00635. Hasegawa, A. and L. Chen (1976), Parametric decay of “Kinetic Alfvén Wave” and its applications, Phys. Rev. Lett., 36, 1362-1365. Hollweg, J. V. (1999), Kinetic Alfvén wave revisited, J. Geophys. Res. 104, 14811, doi: 10.1029/1998JA900132 (1999). Jess, D. B., M. Mathioudakis, R. Erd´elyi, P. J. Crockett, F. P. Keenan, and D. J. Christian (2009), Alfvén waves in the lower solar atmosphere, Science, 323, 1582-1585. Modi, K.V. and R. P. Sharma (2013), Nonlinear interaction of kinetic Alfven wave with fast magnetosonic wave and turbulent spectrum, Phys. Plasmas, 20, 032303; doi: 10.1063/1.4794834 Roux, A., A. Hilgers, H. de Feraudy, D. le Queau, P. Louarn, S. Perraut, A. Bahnsen, M. Jespersen, E. Ungstrup, and M. Andre (1993), Auroral kilometric radiation sources: In situ and remote observations from Viking, J. Geophys. Res., 98(A7), 11,657–11,670, Seyler, C. E., and K. Liu (2007), Particle energization by oblique inertial Alfvén waves in the auroral region, J. Geophys. Res., 112, A09302. Sharma, R. P., Kumar, S., and H. D. Singh (2008), Nonlinear evolution of kinetic Alfvén waves and the turbulent spectra Phys. Plasmas 15, 082902. Sharma, R. P. and H.D.Singh (2009), Density cavities associated with inertial Alfvén waves in the auroral plasma, J. Geophysical Res., 114, A03109. Shen, M. M and D. R. Nicholson (1987), Numerical comparison of strong
Lagmuir turbulence models, Phys. Fluids, 30, 1096. 16. Shukla, P. K., B. Eliasson, L. Stenflo, and R. Bingham (2007), in Recent Research Developments in Plasma Physics, Ed. J.Weiland, Transworld Research Network, Trivendrum,Kerala, India, pp. 51-74. 17. Shukla, P. K., B. Eliasson, and L. Stenflo (2012), Alfvénic solitary and shock waves in plasmas, in multi-scale Dynamical Processes in Space and Astrophysical Plasmas, Eds.M. P. Leubner and Z. Vörös, Astrophys. And Space Sci. Proceedings (Springer, Berlin), 33, 129-141. 18. Shukla, P. K., L. Stenflo and R. Bingham (1999), Nonlinear propagation of inertial Alfvén waves in auroral plasmas, Phys. Plasmas, 6, 1677 19. Shukla, P. K., R. Bingham, J. F. McKenzie, and I. Axford (1998), Solar coronal heating by high-frequency dispersive Alfv´en waves, Solar Phys., 186, 61-66. 20. Stasiewicz, K., P. K. Shukla, G. Gustafsson, S. Buchert, B. Lavraud, B. Thide, and Z. KLo (2003), Slow magnetosonic solitons detection by the Cluster spacecraft, Phys. Rev. Lett., 90, 085002. 21. Stefant, R. J. (1970), Alfvén wave damping from finite gyroradius coupling to the ion 22. Wu, D. J., G. L. Huang, and D. Y. Wang (1996), Dipole density solitons and solitary dipole vortices in an inhomogeneous space plasma, Phys. Rev. Lett., 77, 4346– 4349. Figure Caption Figure 1 - The propagation dynamics of 3DIAW (auroral region) at time t=33.
Figure 1 - The propagation dynamics of 3DIAW (auroral region) at time t=33. ISBN-978-81-932091-2-7
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Thermodynamic analysis of Factors affecting the Performance of Solar Collectors Arvind Kumara, Shiv Lalb and Harenderc* a Mechanical Engineering, Shiv Nadar University, Greater Noida-201314 b Govt. Engineering College, Banswara, Rajasthan, India-327001 Corresponding Author: ak774@snu.edu.in , harender@snu.edu.in
Abstract Thermodynamic analysis has been carried out to understand the performance of flat plate collector and evacuated tube collector and to compare the same in the present study. Major parameters that affect the performance of solar collector are absorptivity and emissivity of absorber, emissivity of glass cover, temperature of absorber plate, collector tilt angle and number of glass covers. All the affecting factors are analyzed numerically and graphs are plotted. It is analyzed that absorber plate temperature has maximum impact over the heat loss from the solar collector. Absorber plate temperature can be maintained at atmosphere temperature for the minimization of heat loss by increasing the mass flow rate of the flowing fluid or by increasing the specific heat capacity of the fluid using nanoparticles. Keywords: Solar-thermal energy, solar collector, Evacuated Tube, flat plate collector 1. Introduction Conventional sources of energy (coal, petroleum etc.) are decreasing day by day and causing global warming [1]. Since last 3 decades, nonconventional sources of energy (Solar Energy, Wind energy, Tidal energy etc.) are being investigated extensively [2-3]. Sun is the only and vast source of solar energy that emits electromagnetic radiation of 0.1-100 µm wavelength at 5800K. Solar-thermal collectors are the devices that absorb the solar irradiation and transfer that heat energy to the fluid for different applications. The main component of a solar collector is absorber having maximum absorptivity i.e. almost equal to unity. Depending upon the type of absorber and thermal losses from the absorber, there are many types of solar collectors (Flat plate collector, evacuated tube collector, concentrating collector etc.) [4]. Absorber plate or tube temperature increases as it absorbs the solar irradiation and some of absorbed heat is radiated back to environment due to emissivity of absorber plate. Radiative heat energy is directly proportional to 4th power of absolute temperature of absorber plate
therefore radiosity increases as the temperature of absorber plate or tube increases. Efficiency of the collector will be maximum when the total absorbed heat energy is transferred to flowing fluid inside the tube with minimum heat losses to atmosphere. In the present paper, every factor affecting the performance of solar collector is analyzed numerically. The performance of solar collector depends mainly on solar intensity G (W/m2), absorptivity of absorber tube (α), emissivity of absorber tube (ε), tilt angle, and mean temperature of absorber tube (Tpm) [5]. The losses from the solar collector are optical losses and thermal losses. Optical losses are due to optical properties (transmissivity, reflectivity) of glass cover [6]. Thermal losses are convective heat loss and radiation heat loss. Convective heat losses are minimized by using glass cover over the absorber plate or tube and radiation losses can be decreased by the maintaining the mean plate temperature equal to ambient temperature. Evacuation between absorber and glass cover minimizes the thermal convective losses. ISBN-978-81-932091-2-7
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2. Mathematical Modelling Useful heat gain of a solar collector can be calculated as follows [7]: đ?&#x2018;&#x201E; = (đ?&#x153;?đ?&#x203A;ź)đ??ş â&#x2C6;&#x2019; đ?&#x2018;&#x2C6; (đ?&#x2018;&#x2021; â&#x2C6;&#x2019; đ?&#x2018;&#x2021; ) Where Q is useful heat gain, Ď&#x201E;Îą is transmittanceabsorptance product of absorber, G is solar intensity (W/m2), and UL is overall heat loss coefficient for the solar collector. 2.1 Flat plate collector Overall heat loss coefficient of flat plate collector UL is calculated as follows [8]: đ?&#x2018;&#x2C6; â&#x17D;Ą â&#x17D;˘ =â&#x17D;˘ â&#x17D;˘ â&#x17D;Ł
đ?&#x2018; đ??ś đ?&#x2018;&#x2021;
â&#x17D;Ą â&#x17D;˘ + â&#x17D;˘đ?&#x153;&#x17D; â&#x2C6;&#x2014; đ?&#x2018;&#x2021; â&#x17D;˘ â&#x17D;Ł â&#x2C6;&#x2014;
đ?&#x2018;&#x2021;
â&#x2C6;&#x2019;đ?&#x2018;&#x2021; đ?&#x2018; +đ?&#x2018;&#x201C;
.
+â&#x201E;&#x17D;
â&#x17D;¤ â&#x17D;Ľ â&#x17D;Ľ â&#x17D;Ľ â&#x17D;Ś
+đ?&#x2018;&#x2021;
â&#x17D;¤ â&#x17D;Ľ â&#x17D;Ľ [2đ?&#x2018; + đ?&#x2018;&#x201C; â&#x2C6;&#x2019; 1] 1 + â&#x2C6;&#x2019;đ?&#x2018; â&#x17D;Ľ đ?&#x153;&#x20AC; đ?&#x153;&#x20AC; + .005đ?&#x2018; (1 â&#x2C6;&#x2019; đ?&#x153;&#x20AC; ) â&#x17D;Ś đ?&#x2018;&#x2021;
+đ?&#x2018;&#x2021;
f = (1- 0.04 hw + 0.0005 hw2) (1 + 0.091N), C = 365.9(1- 0.00883 β +0.0001298 β2) β=Collector Tilt angle (Degree), Îľp =absorber plate emissivity (0.08), Îľg= glass emissivity (0.9), hw = wind heat transfer coefficient (W/m2 o K) = 8.55+2.56Vwind (m/s), Tpm =Absorber plate mean temperature (K) 2.2 Evacuated Tube Solar Collector Total heat loss from an evacuated tube solar collector is due to radiation mainly and heat loss by convection is negligible due to evacuation between tube and glass cover. Heat loss by radiation between absorber tube and glass cover as follows [9]:â&#x201E;&#x17D; =
đ?&#x153;&#x17D;đ?&#x153;&#x20AC; (đ?&#x2018;&#x2021; đ?&#x153;&#x20AC; đ??ˇ(1 â&#x2C6;&#x2019; đ?&#x153;&#x20AC; ) 1+ đ?&#x153;&#x20AC; đ??ˇ
+ đ?&#x2018;&#x2021; )(đ?&#x2018;&#x2021; + đ?&#x2018;&#x2021; )
Where Îľp = absorber tube emissivity (0.08), Îľg = glass emissivity (0.92), D=Absorber tube outer diameter (37 mm), Dg = Glass cover diameter (47 mm), Tp = tube temperature (Kelvin), Tg = glass temperature (Kelvin)
Useful heat gain of ISO 9459-2 evacuated tube solar collector [10], Qu=a1+a2 G+a3 (Twi-Ta) The correlation coefficients for the ISO 9459-2 evacuated tube model are a1= 0.597, a2= 1.066, a3= -0.208 and Twi is Tank Temperature and G is solar irradiation for a day. Instantaneous efficiency of evacuated tube solar collector is written by [11]: (đ?&#x2018;&#x2021; â&#x2C6;&#x2019; đ?&#x2018;&#x2021; ) (đ?&#x2018;&#x2021; â&#x2C6;&#x2019; đ?&#x2018;&#x2021; ) đ?&#x153;&#x201A; =đ?&#x153;&#x201A; â&#x2C6;&#x2019;đ?&#x2018;&#x17D; â&#x2C6;&#x2019;đ?&#x2018;? đ??ş đ??ş đ?&#x2018;&#x2021;= average of Inlet and outlet temperature in the tube, đ?&#x153;&#x201A; =optical efficiency, Ta= ambient temperature, a & b= heat loss constant of evacuated tube collector Maximum amount of absorbed heat energy can be transferred by increasing the mass flow rate (m) of flowing fluid inside the absorber or increasing the specific heat capacity of fluid (cp) [12]. Q= mcp(Tp-Tw) Specific heat capacity of the flowing fluid can be increased by using metal nanoparticles or carbon nanoparticles in the flowing fluid [13]. đ?&#x2018;? , = đ?&#x153;&#x2122;đ?&#x2018;? , + (1 â&#x2C6;&#x2019; đ?&#x153;&#x2122;)đ?&#x2018;? , Where nf, n and f refer to nanofluid, nanoparticle and base fluid, respectively. Specific heat of nanofluid will be optimum at optimum volume fraction of nanoparticles. As the specific heat capacity cp increases, maximum amount of heat can be transferred by the same mass flow rate. 3. Results and Discussion 3.1 Effect of number of glass cover over heat transfer coefficient for FPC Losses of convective heat energy from a flat plate collector have been minimized by increasing the number of glass cover as shown in figure [1]. By increasing the number of glass cover, solar energy reflected by glass cover is increased. Thus, the useful heat gain by the solar collector decreases. By increasing number of glass cover, maximum amount of solar energy is reflected by glass cover. Therefore maximum 2 glass cover should ISBN-978-81-932091-2-7
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n=1, V=1 n=2, V=0
3.5 3 2.5 2 1.5 1
3
n=1
n=2
2.5
n=3
n=4
298
318 338 358 378 ABSORBER TEMPERATURE (K)
398
Figure 2. Effect of wind speed over heat transfer coefficient for FPC
2 1.5 1 0.5 298
318
338
358
378
Absorber Temperature (K)
398
Figure 1. Effect of number of glass cover over heat transfer coefficient for FPC 3.2 Effect of wind speed over overall heat loss of flat plate collector As the wind speed increases, Reynold’s number increases. Therefore, natural convection is turned to forced convection. Heat transfer coefficient for forced convection is greater than that for natural convection. As heat transfer coefficient increases, heat loss from the flat plate collector increases. Heat loss coefficient of flat plate solar collector increases with increasing wind speed as shown in figure [2]. Flat plate collector having one glass cover is much affected by wind speed and flat plate collector having two glass over, overall heat transfer coefficient is not much affected by increasing the wind speed as shown in figure [2].
3.3 Heat loss by radiation between absorber tube and glass cover of ETC Evacuated tube solar collector is the best collector among all the collectors due to minimum heat loss to atmosphere. There is radiation heat loss from evacuated tube solar collector and heat losses due to convection between absorber tube and glass cover is neglected. As there is vacuum between absorber tube and glass cover, there is no fluid to transport thermal energy from absorber tube. But there will be heat losses too due to convection from glass cover to ambient. Thus overall heat loss confident of evacuated tube solar collector is increased. Overall heat loss coefficient (W/m2K)
Heat Loss Coefficient (W/m2K)
3.5
n=1, V=0 n=1, V=4
4 HEAT LOSS COEFFICIENT (W/M2K)
be used for optimization of solar energy. More the glass cover, greater will be the reflected energy. After 2 glass covers, there is minute change in heat losses as shown in figure [1] and the heat losses due to convection and radiation are increasing as mean plate temperature increases. Heat losses from the absorber can be decreased by maintaining the absorber temperature almost equal to ambient temperature. In the figure [1], n denotes the number of glass cover.
1
Ta=288K
0.95
Ta=298K
0.9
Ta=308K
0.85 0.8 0.75 0.7 0.65 0.6 0
20
40
Tp-Ta
60
80
100
Figure 3. Effect of ambient temperature over heat loss coefficient for ETC ISBN-978-81-932091-2-7
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Difference between absorber tube temperature and ambient temperature affects the performance of evacuated tube solar collector. Higher the difference of temperature between absorber tube and ambient, higher will be losses as shown in figure [3]. Heat transfer coefficient due to convection from glass cover to ambient is taken as 12.7 W/m2 for calculation of overall heat transfer coefficient. 3.4 Effect of absorber tube emissivity over heat transfer coefficient for ETC There are mainly three component of an evacuated tube solar collector affecting the performance of that evacuated tube solar collector i.e. absorber tube, fluid to transfer the absorbed heat and glass cover. Solar irradiation is absorbed by absorber tube. Absorber tube should have higher absorptivity. Higher the absorptivity, greater will be the absorbed heat. But by Kirchhoff’s law, the emissivity of a body which is in thermal equilibrium with its surrounding is equal to its absorptivity of the body. For the higher value of absorptivity, a surface coating is used over the absorber tube. Ep=0.08 Ep=0.1 Ep=0.2 Ep=0.5
4 3.5 3
3.5 Heat gain by Evacuated Tube Solar Collector vs Tank Temperature Evacuated tube solar collector is the best collector due to evacuation between absorber tube and glass cover. There is no fluid transporting thermal energy between absorber tube and glass cover. Hence there will be no heat losses due to convection. There will be only radiation losses from the absorber tube. Radiative energy from a body is directly proportional to 4th power of absolute temperature of that body. Heat losses due to radiation from absorber tube depends on the absorber tube temperature and emissivity of absorber tube. Radiation losses can be minimized by minimizing the absorber tube temperature equal to ambient temperature by increasing mass flow rate of fluid flowing inside the absorber tube or by increasing the specific heat capacity of the fluid using nanofluid. Lower the tank temperature, Higher will be the useful heat gain by evacuated tube solar collector as shown in [figure 5]. 30
Useful Heat gain (MJ/day)
Heat transfer coefficient (W/m2K)
4.5
absorptivity almost equal to unity, and lower the value of emissivity.
2.5 2 1.5 1 0.5
25 20 15 10 5
0 298
318 338 358 378 Absorber Temperature (K)
398
Figure 4. Effect of absorber tube emissivity over heat transfer coefficient Emissivity of absorber tube affects the performance of evacuated tube solar collector as shown in figure [4]. Higher the value of emissivity, greater the heat loss coefficient is. Absorber tube should have higher the value of
298
318
338
358
tank Temperature (K)
378
398
Figure 5. Effect of tank temperature over useful heat gain by ETC The slope of useful heat gain by evacuated tube solar collector to the tank temperature is negative as shown in figure [5]. Useful heat gain by evacuated tube solar collector is decreasing as tank temperature is increasing. Higher the tank temperature, greater will be the heat losses. ISBN-978-81-932091-2-7
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Useful Heat gain (MJ/day)
Average temperature in the tube should be as low as ambient for maximum heat gain. Difference between tank temperature and ambient temperature is taken as (dT) in the figure [6]. As the temperature difference between absorber tube and atmosphere increases, useful het gain decreases and losses increases. As the Absorber tube absorbs the solar irradiation, temperature of absorber tube increases. As the temperature of absorber tube increases, loss due to radiation increases as shown in figure [6]. More the difference of temperature between tube and ambient, higher will be the radiation losses and lesser will be useful heat gain. 30 25 20 15 dT=20 dT=10 dT=0
10 5 0 0
5
10
15
20
Irradiation (MJ/m2)
25
Figure 6. Effect of ambient temperature over Useful heat gain by ETC 3.6 Overall heat loss by ETC and FPC FPC, n=1
Heat Loss coefficient (W/m2K)
4
FPC, n=2
3.5
ETSC
3 2.5 2 1.5 1 0.5 0 298
318
338
358
378
398
Absorber Temperature (K)
Figure 7. Comparison of Heat loss coefficient for FPC and ETC
Heat loss coefficient for an evacuated tube solar collector and flat plate collector are compared as shown in figure [7]. Heat loss coefficient for flat plate collector is higher than that for evacuated tube solar collector. Therefore, heat loss from flat plate collector is higher than that of evacuated tube solar collector. Heat loss by flat plate solar collector having (n = 1) glass cover is maximum and heat loss by FPC having two glass cover is less than that of one glass cover and greater than that of ETC. Heat loss by ETC is minimum as there are radiation heat loss only as shown in figure [7]. 4. Conclusion By using selective coating or nano-coating on absorber tube, absorptivity is maximized (= 0.92) so maximum amount of irradiation is absorbed and temperature of the tube increases. As the tank temperature increases, heat losses by radiation as well as convection also increases. Heat loss by convection is minimized by using evacuation between absorber tube and glass cover but heat loss by radiation does not need a medium to propagate. Therefore heat loss by radiation is not affected by evacuation. As the temperature of absorber increases, heat loss by radiation also increases. By maintaining the absorber temperature almost equal to atmosphere temperature, heat loss by radiation can also be minimized. Absorber temperature can be maintained almost equal to atmosphere temperature by increasing the mass low rate of the flowing fluid inside the absorber or by increasing the specific heat capacity of flowing fluid using carbon nanoparticles. Evacuated tube solar collector is the more efficient than flat plate collector having minimum heat losses. For flat plate collector, number of glass cover over absorber plate should be 2 for optimization of absorbed solar energy. More the number of glass covers, higher will be losses due to reflection by glass cover. Heat losses are not affected much by wind speed having 2 glass cover over absorber. ISBN-978-81-932091-2-7
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References [1] D. Mills, Advances in solar thermal electricity technology, Solar Energy 76 (2004) 19–31. [2] D.Y. Goswami, S. Vijayaraghavan, S. Lu, G. Tamm, New and emerging developments in solar energy, Solar Energy 76 (2004) 33– 43. [3] D.Y. Goswami, Solar thermal power technology: present status and ideas for the future, Energy Sources 20 (1998) 137–145. [4] M.A. Sabiha, R. Saidur, Saad Mekhilef , Omid Mahian, Progress and latest developments of evacuated tube solar collectors, Renewable and Sustainable Energy Reviews, Volume 51, November 2015, Pages 1038-1054. [5] E. Zambolin, D. Del Col, Experimental analysis of thermal performance of flat plate and evacuated tube solar collectors in stationary standard and daily conditions, Solar Energy 84 (2010) 1382–1396. [6] E. Zambolin, D. Del Col, An improved procedure for the experimental characterization of optical efficiency in evacuated tube solar collectors, Renewable Energy, Volume 43, July 2012, Pages 3746. [7] L.M. Ayompe, A. Duffy, Thermal performance analysis of a solar water heating system with heat pipe evacuated
tube collector using data from a field trial, Volume 90, April 2013, Pages 17-28. [8] Solar Energy, Principles of Thermal Collection and Storage, S. P. Sukhatme, J. K. Nayak (Page-124) [9] Liangdong Ma, Zhen Lu, Jili Zhang, Ruobing Liang, Thermal performance analysis of the glass evacuated tube solar collector with U-tube, Building and Environment 45 (2010) 1959-1967 [10] G.L. Morrison, I. Budihardjo, M. Behnia, Water-in-glass evacuated tube solar water heaters, Solar Energy 76 (2004) 135–140. [11] Tin-Tai Chow, Zhaoting Dong, Lok-Shun Chan, Kwong-Fai Fong, Yu Bai, Performance evaluation of evacuated tube solar domestic hot water systems in Hong Kong, Energy and Buildings 43(2011) 3467-3474. [12] Indra Budihardjo, Graham L. Morrison , Masud Behnia, Natural circulation flow through water-in-glass evacuated tube solar collectors, Solar Energy 81 (2007) 1460– 1472. [13] A.H. Elsheikh, S.W. Sharshir, Mohamed E. Mostafa, F.A. Essac, Mohamed Kamal Ahmed Alif, Applications of nanofluids in solar energy: A review of recent advances, Renewable and Sustainable Energy Reviews, November 2017, In Press, Corrected Proof.
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Reactive power control in distribution line by using D-STATCOM Dharaben B Ghamawala, Bhupendra R. Parekh Department of Electrical Engineering, BVM Engineering College Vallabh Vidyanagar Corresponding Author: dharabenghamawala@gmail.com
ABSTRACT This paper discusses about the application of distribution static compensator (D-STATCOM) in distribution line to control reactive power flow. In order to reduce the reactive power burden and to mitigate other undesirable effects caused by inductive load, reactive power flow should be controlled in distribution line. There is four different control strategies to control the power flow. Here a voltage source converter type D-STATCOM based on instantaneous symmetrical component theory is connected with distribution line to control power flow and Hysteresis current control is used to generate the gate pulse for switching device of D-STATCOM. The distribution line and DSTATCOM are modeled using MATLAB-SIMULINK software. Finally, after the design, it provides the effective full/partial reactive power compensation for variable load and also improve the power factor. Keywords: D-STATCOM, Distribution line, Variable inductive load, Reactive power control, Instantaneous symmetrical component theory reference current components. For this 1. INTRODUCTION purpose, many control schemes are mentioned Nowadays in distribution systems, major in literature and some of these control power consumption has been in reactive loads, strategies are instantaneous reactive power such as fans, pumps, electric motors, nonlinear (IRP) theory, instantaneous symmetrical loads etc. These loads draw lagging powercomponents, synchronous reference frame factor currents and therefore increase reactive (SRF) theory and Current compensation using power burden in the distribution system. dc bus regulation. Moreover, In the presence of unbalanced In this paper, a voltage source converter type nonlinear loads, situation become worsen. D-STATCOM is used to control the reactive Excessive reactive power demand increases power flow in the distribution line. For feeder losses and reduces active power flow generation of reference current, instantaneous capability of the distribution system, whereas symmetrical component theory has been used unbalancing affects the operation of and hysteresis current control strategy has been transformers and generators. The reactive used for generating the gate pulses for power flow affects many parameters of switching device of vsc type D-STATCOM. distribution line, which introduced many The D-STATCOM based on this control technical issues in line. As these issues are very scheme can provide reactive power control important, reactive power compensation under varying load condition should be provided in the distribution line. The 2. D-STATCOM conventional compensating devices fail to D-STATCOM is a shunt connected compensation under varying load condition compensating power electronic device and also suffer from many drawbacks. So, A consisting of the Distribution STATic COMpensator VSC, DC energy storage, output filter and (DSTATCOM) is one of most advanced, coupling transformer/ interface reactor. VSC versatile and suitable device for compensation converts the DC voltage of capacitor storage of reactive power and unbalance loading in the device into the balanced set of three phase AC distribution system. output voltages. The generated voltages are in The performance of DSTATCOM depends on phase and interconnected with the utility grid the control algorithm used for extraction of through interface reactor/ coupling ISBN-978-81-932091-2-7
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transformer. Fig 1 represents the generalized connection of D-STATCOM to distribution line. Proper adjustment of the magnitude and phase angle of the D-STATCOM output voltages allow effective control of reactive and real power flow between the D-STATCOM and distribution line.
Fig. 1. A generalized connection of DSTATCOM to Distribution Line. If VI is equal to Vpcc, Zero reactive power flow from D-STATCOM to distribution line and the D-STATCOM does not absorb or generate any reactive power. When V1 is greater than Vpcc, the D-STATCOM performs a capacitive reactance connected at its terminal. The compensating current flows from the D-STATCOM to the distribution line and the device provide reactive power to distribution line. If phase angle of voltage of D-STATCOM is kept leading Vpcc, it can supply real power to distribution line. By real power flow exchange, it is used for mitigating the internal losses of the inverter for maintaining the voltage across capacitor constant. Different controllers and control strategies are used for DSTATCOM to provide the control of power flow in distribution line under dynamic load varying condition .Here in this paper, Instantaneous symmetrical component theory based control strategy has been used to control the functioning of D-STATCOM. The other controllers having been used here are Hysteresis Current controller (for Gate Pulse Generation) & PI Controller (for maintaining
the voltage of Capacitor of VSC i.e. D.C. Link Voltage constant). 3. CONTROL SCHEME Instantaneous symmetrical component theory is basically the symmetrical component theory being applied to instantaneous voltages and currents. The unbalanced voltages & currents can be converted into 3-set of balanced voltages & currents i.e. Positive sequence, negative sequence & zero sequence components by using this instantaneous symmetrical component theory. Here, the control strategy is used to generate the reference currents. Two basic objective of this proposed control scheme are : The source should supply positive sequence component of power only To make supply currents balanced such that: isa + isb + isc = 0 (1) As we assuming that the source current lag by voltage by angle φ, then positive sequence component of voltage also lag the positive sequence current and we would obtained equation (2) (Vsb –Vsc-3βVsa) isa + (Vsc –Vsa-3βVsb)isb + (Vsa –Vsb-3βVsc)isc = 0 (2) Where, β = 1/√6 tan φ Now, if D-STATCOM is used to provide reactive power compensation & source should supply only average component of load power P1 and the power losses occurring in switches of VSI i.e Ploss would be supplied by source itself , so equation (3) is obtained Vsaisa +Vsbisb +Vscisc = Pl + Ploss (3) The equation for calculating reference value of source currents are obtained in following equation (4) , (5) and (6)by using equation (2) isar = Vsa + (Vsb – Vsc ) β (P1 + Ploss) / (Vsa^2 +Vsb^2 + Vsc^2) (4) isbr= Vsb + (Vsc – Vsca ) β (P1 + Ploss) / (Vsa^2 +Vsb^2 + Vsc^2) (5) iscr = Vsc + (Vsa – Vsb ) β (P1 + Ploss) / (Vsa^2 +Vsb^2 + Vsc^2) (6) The reference compensenting current equation to be provided by D-STATCOM would be as shown in following equation (7), (8) and (9) irca = ila – isar (7) ircb = ila – isbr (8) ISBN-978-81-932091-2-7
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ircc = ila – iscr (9) These compensating reference current irca , ircb , ircc are then compared with actual currents ica, icb & icc respectively and then hysteresis current controller is used to generate the gate pulses of three legs of Inverter unit of D-SATACOM. 4. SIMULATIONS AND RESULTS The design of D-STATCOM with instantaneous symmetrical component theory based control strategy is developed to control reactive power flow in distribution line in MATLAB SIMULINK software. The system is employed with three phase programmable voltage source with configuration of 415V, 50 Hz. The Main simulation circuit is shown in Fig. 3, while the sub-circuits for control scheme and D-STATCOM used in the simulation are shown in Fig. 4 & Fig. 5.The values of various parameters of Base system and D-STATCOM considered are shown are listed in Table I and II .
TABLE III. EFFECT OF LOAD VARIOUS PARAMETERS DISTRIBUTION LINE S r n o
So ur se vo lta ge
Powe r Dema nd
P ( K W ) 1
41 5
1 0
Q ( K V A R ) 2 0
2
41 5
2 0
2 0
3
41 5
2 0
3 0
4
41 5
3 0
5 0
TABLE I.PARAMETER OF BASE SYSTEM Source voltage & frequency
415 V (Line to Line ) , 50Hz
Total line resistance
0.1234Ω
Total line reactance
0.045mH
Load connected
Variable parallel resistive & inductive (R-L)load
Powe r Supp lied By Sour ce P Q ( ( K K W V ) A R ) 1 1 0 9 . . 1 7 4 1 1 1 9 9 . . 9 4 3 8 2 2 0 9 . . 2 1 8 3 4 0 7 . . 7 9 5 3
Power Receive d By Load
ON OF
Lo ad Vo lta ge (V )
Cu rre nt (A)
Power factor
P (K W )
Q (K V A R)
9. 8
19 .6 8
41 1. 1
27. 1
0.457
19 .4 2
19 .4 2
40 7. 5
34. 41
0.511
19 .4
29 .0 9
40 7. 7
43. 29
0.569
28 .6 1
47 .6 3
40 3. 6
69. 39
0.540
TABLE II: PARAMETER OF D-STATCOM Reference D.C. Link Voltage
800 V
D.C. link capacitor
1000µF
Coupling Inductance
0.025H
Pi Controller Constant
Kp = 0.85 , Ki = 5
Fig 2 Base System
Fig 3 Main Simulation Circuit With DSTATCOM ISBN-978-81-932091-2-7
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Fig 5 Results of Real & Reactive Power Flow of Source, D-STATCOM & Load TABLE IV. SIMULATION RESULTS POWER SUPPLIED BY SOURCE S r n o
Fig 4 Sub circuit of D-SATACOM POWER RECEIVED BY LOAD : POWER SUPPLIED BY D-STATCOM:
S o u r s e v o lt a g e
Power Dema nd
Power Suppli ed By Source
Power Supplied By DSTAT COM
Power Receive d By Load
P ( K W )
P ( K W )
P (K W)
P ( K W )
Q (K V A R)
1 . 1 7
3.2
1 0 . 3 4 1 9 . 8 7 2 0 . 3
19. 85
1 9 . 4 9 1 9 . 6 1 2 9 . 2 2
Q ( K V A R ) 0 . 5 0 2 0 . 5 4
2 . 3 2
6.8
3 0 . 9
48. 63
1
4 1 5
1 0
Q ( K V A R ) 2 0
2
4 1 5
2 0
2 0
3
4 1 5
2 0
3 0
4
4 1 5
3 0
5 0
9 . 6 5
1.1 7
1.6
Q ( K V A R ) 1 9 . 4 1 9 . 0 2 2 8 . 2 7 4 6 . 6 7
19. 46
29. 24
L o a d V o lt a g e ( V )
Curre nt (A)
Po we r fac tor
4 1 2 . 6 4 0 9 . 9 4 0 9 . 9 4 0 7 . 3
13.35
0.9 98
26.86
0.9 95
27.03
0.9 97
40.26
0.9 96
: 5. CONCLUSION D-SATACOM based on instantaneous symmetrical component control strategy is proposed to control the reactive power flow in distribution line. Hysteresis current controller is used in this proposed structure for providing gate pulses to switching device. The simulation results show that D-STATCOM based on the proposed strategy provides reactive power compensation to distribution line with variable load condition & the source supplies almost negligible reactive power. therefore, source power factor improves to 0.99. REFERENCES 1. Arindam Ghosh, Gerard Ledwich, “Power Quality Enhancement using Custom Power Devices”, Kluwer Academic Publisher, 2002. 2. N.G.Hingorani & L.Gyugyi, “Understanding FACTS”, Standard Publishers, Delhi, 2001. ISBN-978-81-932091-2-7
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3. 4.
5.
6.
7.
8.
Vinay M. Awasthi , Mrs. V. A. Huchche “Reactive Power Compensation using DSTATCOM” , IEEE 2016 U. Koteswara Rao, Mahesh K. Mishra & Arindam Ghosh, “Control Strategies for Load Compensation Using Instantaneous Symmetrical Component Theory Under Different Supply Voltages”, IEEE Transactions on Power Delivery, 2008. Sreejith S, Upama Bose, K. Muni Divya Sree Vachana, Vallathur Jyothi, “Application of D-STATCOM as Load Compensator for Power Factor Correction”, IEEE International Conference on Control, Instrumentation, Communication and Computational Technologies (ICCICCT), 2014 Bhim Singh, Alka Adya, A.P.Mittal, & J.R.P. Gupta, “Modeling, Design and Analysis of Different Controllers for DSTATCOM”. IEEE transactions, 2008. Pradeep Kumar, “Simulation of Custom Power Electronic Device D-STATCOM – A Case Study”, IEEE, India International Conference on Power Electronics (IICPE), 2010. Hirak K. Shah, P.N. Kapil & M.T.Shah, “Simulation & Analysis of Distribution Static Compensator (D-STATCOM)”, IEEE, 2011.
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State of Health Assessment of Lead Acid Cells as a Function of Conductance
Gauri1*, Manish Singh Bisht2, P.C Pant2, Rajesh Kumar3, R.P. Gairola4 1” Dept. of Physics, Birla Campus, HNB Garhwal University Srinagar Garhwal, Uttarakhand, India 2 Ministry of New and Renewable Energy, Govt. of India, New-Delhi, India 3 National Institute of Solar Energy, Gurgaon, India 4 Dept. of Physics, HNB Garhwal University Srinagar Garhwal, Uttarakhand, India * Corresponding Author. E-mail: g.negi10@gmail.com Abstract: Low performing batteries/cells reduce the efficiency of whole battery bank. Sometimes the condition becomes so severe that it results in malfunction of the whole bank. The state of health analysis of even a single cell/battery through conventional load testing requires a lot of time and wastage of power. It is required to discover and test a method of battery/cell testing which is quick, reliable and can be performed on operational batteries. The aim was to investigate whether the conductance of the flooded and VRLA lead-acid cell indicates real state of health of operational cells and if yes, could there be a reference value of conductance for the cells of a particular capacity or not. Key Words: Lead acid, conductance, Battery bank, State of health. 1. Introduction: Batteries form a very essential part of solar photovoltaic applications. Being a very costly device, it needs to be properly examined in terms of capacity before being deployed in the field. When a number of cells are connected in series to form a battery bank, it becomes very essential that all the cells have equal capacities and each one is performing well. A low-performing cell can lead to enhanced degradation of the whole bank resulting in loss of both money and valuable power generated by the solar modules. In some cases it can even lead to breakdown of the whole plant. But examining the state of health of a battery is no easy task. For capacity test on a battery it is required that the sample is subjected to a number of cycles of charge and discharge under controlled conditions at C10 rate. As per IEC and or BIS* standards a typical capacity test would require about 40 hours per cycle and to perform minimum 10 cycles is mandatory for capacity test. It consumes a lot of time as well as valuable power is wasted in charging and discharging and when a complete bank has to be tested it can take months to finish the testing. The foremost problem isthat you cannot examine the battery once being installed
as a bank. For capacity test on each cell you have to dismantle the whole bank resulting in interruption of whole SPV plant. And if the plant is supplying crucial loads you do not have liberty to do that. Normal field procedure of SOC examination is to collect specific gravity readings of the battery/cells, but these will only serve as a superficial prediction of the level of charge of the battery, but not provide information on the storage capacity of the battery. And in case it is a VRLA cell you have to think of some other options. As batteries degrade through field use, their capacity goes down. The battery bank operator or owner is in dark how to find the state of health of his bank or the faulty battery of the bank which is not performing well. The aim of this article is to present and discuss results for a relatively new method of examining operational field batteries, under actual conditions, which is quick, reliable and does not involve any waste of power. This method is based on assessment of state of health of a battery though its conductance. Conductance describes the ability of a battery to conduct current. In scientific terms, it is the real part of the complex admittance. Various test data ISBN-978-81-932091-2-7
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have shown that at low frequencies, the conductance of a battery is an indicator of battery state-of-health showing a linear correlation to a batteryâ&#x20AC;&#x2122;s timed-discharge capacity test result and trending this measurement can be used as a reliable predictor of battery end-of-life (H. Giess, 1999). This paper also presents a reference value of conductance for the flooded and VRLA lead acid cells of a particular capacity so that they may be used as reference to examine batteries of the same capacity. The use of conductance measurements to evaluate automotive battery performance was first reported in 1975 by Champlin [1]. It demonstrated a strong positive linear correlation between load tests and measured conductance for automotive batteries. Since then impedance and more recently conductance has been attracting both users and manufacturers to determine battery state-of-health [2-4]. Initially, the conductance testing was limited to VRLA cells only but later the interest expanded to flooded cells and nickel-cadmium cells as well[5]. Now a number of studies have been published on this topic [6-12]. This research work was carried out on two operational battery banks of 240V, 1000Ah each, consisting of 120 cells of 2V, 1000Ah at National Institute of Solar Energy, Gurgaon, Haryana (INDIA). One of these banks was of flooded type while the other one was of VRLA technology. These banks, installed 2 years before, are connected to two different inverters of 10KVA and 50KVA respectively and are being used to power the loads of the campus. Both inverters are hybrid inverters and operate on grid as well as solar power. Both the inverters are also connected to the generator so that battery banks are not consumed to higher DOD. These banks are also provided equalizing charge once in a month to ensure proper health. Regular maintenance and topping up with water is also carried out as per schedule. 2. Measurement Technique:
For measurement 5 new samples of same type and capacity as existing ones were purchased from same manufacturer. These new batteries were subjected to capacity test for 10 cycles each at C10 rate and room temperature to have normal filed conditions. The capacity test was performed with the help of a Life Cycle Network (LCN) Machine make Bitrode Corporation, USA. It is a programmable power supply and inbuilt load having automatic data collection feature. It records voltage, current, Amperehour, Watt-hour and temperature at preset intervals. At full charged conditions these batteries were examined with the help of a Battery Analyzer make Midtronics, USA. The battery analyzer is a digital meter which when attached to the sample provides voltage and corresponding conductance values. Battery conductance is measured by evaluating the voltage response to a small, select frequency AC current signal briefly impressed on the battery. The resultant conductance measurement provides pertinent battery information without the need of bringing the battery to full discharge. As a battery discharges, its conductance and capacity are reduced with a simultaneous drop in power in a predictable manner due to the depletion of conductive active materials. The value in conductance or any other Ohmic measurement can be more directly described asAn increased internal resistance or reduced measured conductanceof a cell results in a reduction of the expected capacity or discharge performance of the cell (W. Cantor et.al., 1998.). Thus, conductance is an indication of battery state of health as well as a function of the charge state of a battery. The battery analyzer is powered by a battery source installed inside and does not draw any power from the bank. The conductance values and corresponding value of voltages were recorded. A battery analyzer was now used to individually examine in total 240 cells of both the banks and conductance of the cells along with the corresponding voltage was noted. The battery bank was maintained at full charge during the ISBN-978-81-932091-2-7
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testing and the specific gravity values denoting charged conditions were also recorded. The conductance values of the cells at a particular voltage level were sorted to get maximum inputs for same voltage and conductance.The conductance values of the cells of battery banks were compared with those of new ones. The cells which showed significantly lower conductance values than new batteries were tested for capacity on Bitrode tester. Capacity test was performed on such cells as per the standards and the data was recorded. 10 random samples from the remaining batteries which showed relatively good conductance values were also examined for capacity. Data Analysis: 1094 1092
Capacity vs. Conductance
1090 1088 1086 1084 y = 0.0128x + 709.08 R² = 0.988
1082 1080 1078
1076 28600 28800 29000 29200 29400 29600 29800 30000
Fig. 1 Capacity vs. conductance of new flooded cells
Capacity vs conductance 1180 1160 1140
1100 1080 31200 31400 31600 31800 32000 32200 32400 32600
Fig. 3 Capacity vs. conductance of unused VRLA cells Fig. 1 show the capacity vs. conductance values of new and unused cells or reference cell of flooded type. Each cell is having a capacity greater than their rated capacity. The graph clearly reflects that higher the capacity higher is conductance. The correlation factor for the above values comes out to be 0.988 which denotes a linear relationship between the capacity and conductance. Similarly Fig. 2 shows capacity vs. conductance plot for comparatively healthy used flooded cells.The capacity of these cells had degraded over time and the same was reflected by their reduced conductance and capacity values as compared to the new cells.These are the cells which showed good capacity and conductance values as compared to the reference cells. It also supports the claim that the capacity and conductance bear a linear relationship with respect to each other.
Capacity Vs. Conductance
Capacity vs conductance
1000 800 600
y = 0.078x - 1112.4 R² = 0.9693
400 200 0 21000
22000
23000
24000
25000
y = 0.0651x - 949.07 R² = 0.9253
1120
26000
Fig. 2 Capacity vs. conductance of healthy used flooded cells
900 800 700 600 500 400 300 200 100 0 22600
y = 0.231x - 4627.6 R² = 0.9693
22800
23000
23200
23400
Fig. 4 Capacity vs. conductance of healthy used VRLA cells ISBN-978-81-932091-2-7
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Fig. 3 Reflects the capacity vs. conductance plot of reference VRLA cells denoting a linear relationship between the two. Fig. 4 also confirms the linear relationship between capacity and conductance of used and comparatively healthy VRLA cells. During conductance testing some of the cells in both type of banks were found to be having very low conductance values as compared with other batteries in the same bank. These cells were identified and capacity tests were performed on these. Fig.5 and fig. 6 represent capacity vs. conductance plots of flooded and VRLA technology respectively. Capacity vs conductance 70
The above figures depict that even at very low state-of-charge conductance bears a linear relationship with the capacity. Reference Value of Conductance: Conductance of unused VRLA cells 32800 32600 32400 32200 32000 31800 31600 31400 31200 31000 30800 1
60 50
30
10 0 50
100
150
200
Fig. 5 Capacity vs. conductance plot of very weak flooded cells Capacity vs conductance 140
y = 0.8015x - 88.607 R² = 0.9386
60 40 20 0 50
100
2
3
4
5
Fig. 8 Conductance of unused flooded cells of 1000Ah
100
0
5
30000 29800 29600 29400 29200 29000 28800 28600 28400 28200 1
120
80
4
Conductance of unused flooded cells
20
0
3
Fig. 7 Conductance of unused VRLA cells of 1000Ah
y = 0.7301x - 59.557 R² = 0.9561
40
2
150
200
250
300
Fig. 6 Capacity vs. conductance plot of very weak VRLA cells
Both the above figures depict that the conductance values for 2V, 1000Ah cells of both the technologies are above a certain mark in new and unused cells. Considering Fig. 2 and Fig. 4 for used and comparatively healthy cells it is confirmed that the conductance values lie in a specific range. Though the results are not highly accurate but they do specify a range in which the conductance values should lie for a specific capacity of batteries. ISBN-978-81-932091-2-7
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3. Conclusion: The conductance value of a battery reflects the integrity of inter-cell connections, ionic conductivity of the electrolyte, specific gravity of the cells and the actual battery state of charge. The test results are the product of the internal electrical resistance of the cells and reflect the combined influences of the mechanical state of health in the cells and the electrochemical condition or efficiency of the grid/plate structures. As a battery ages, the positive plate will deteriorate and change chemically adversely affecting the ability of the battery to perform. This normal aging process begins when the battery is activated during the formation process at the end of the battery production lineand will continue for life of the battery. For power provisions, this means that conductance can be used to track changes and detect battery defects, shorts, open circuits and prolonged undercharging, which will reduce the ability of the battery to perform. Conductance test measurements become a valuable tool to identify the point at which the battery is approaching its end of service life. The test results reflect that the conductance technology may be a useful tool to examine new or field batteries for their state-of-health. Conductance bears a linear relationship with the battery capacity which is a direct indication of battery health. This linear relationship is maintained even at low state-of-health of the batteries. Using conventional load testing methods to determine battery capacity requires time and power whereas conductance testing method is quick and reliable. Though exact capacity cannot be predicted but it can provide a tentative idea of battery health. It could prove useful for examining batteries in large quantities such as tenders or inspections where load testing seems impossible for each sample. References: *BIS- www.bis.org
1. 2. 3. 4.
5. 6. 7. 8. 9. 10. 11. 12. 13.
14.
15. 16.
K.S. Champlin, Talk presented to 1975SAE Off-Highway Vehicle Meet, Milwaukee, WI, USA, Sept. 1975. F.J. Vaccaro and P. Casson, Proc. 1987 INTELLEC Conf., pp. 128-135. S. L. DEBardelaben, Proc. 1988 INTELLEC Conf., pp. 394-397. D.O. Feder, Talk presented to 103rd Convention of Battery Council International, Apr. 1991, Washington, DC, USA. M.J. Hlavac and S.J. McShane, Proc, 1993 Association American Railroads, Eastern Region Meet, Orlando, FL, USA. D.O. Feder, T.G. Croda, K.S. Champ& S.J. McShane and M.J. Hlavac, J. Power Sources, 40 (1992) 235. D.O. Feder, T.G. Croda, K.S. Champlin and M.J. Hlavac, Proc. 1992 INTELEC Cone:, pp. 218-233. G.J. Markle, Ptwc. 1992 INTELEC Co& pp. 212-217. S.S. Misra, T.M. Noveiske, L.S. Holden and S.L. Mraz, Pnx. 8th Annual Battery Cant Applications and Advances, 1993. M.J. Hlavac, D.O. Feder and D. Ogden, Proc. American Power Con&, 1993, Vol. 1, pp. 44-57. B. Jones, From. Ilth Int. Lead Con& Venice, Itab, I993. D.O. Feder, M.J. Hlavac and W. Koster, J. Power Sources, 46 (1993) 391. H. Giess "Operation of VRLA Batteries in Parallel Strings of Dissimilar Capacities", Proceedings of 21st Intelec, 1999 W. Cantor , E. Davis , D. Feder and M. Hlavac "Performance Measurements and Reliability of VRLA Batteries â ” Part II: The Second Generation", Proceedings of 20th Intelec, 1998 D. Funk and E. Davis Battery Performance Monitoring by Internal Ohmic Measurements, 1997 W. Ross and P. Budney "Development of a Battery Run Time Algorithm and a Method ISBN-978-81-932091-2-7
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for Determining its Accuracy", Proceedings of 17th Intelec, pp.277 -283 1995 17. M. Troy , D. Feder , M. Hlavac , D. Cox , J. Dunn and W. Popp Midpoint Conductance Technology Used in Telecommunication Stationary Battery Applications, 1997 18. M. Hlavac and D. Feder "VRLA Battery Monitoring Using Conductance Technology", Proceedings of 17th Intelec, pp.285 -291 1995
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CONTROL OF CURRENT AND VOLTAGE FOR MICRO GRID Dhaval Subhashchandra Vyas, Bhupendra R. Parekh Department of Electrical Engineering, BVM Engineering College Vallabh Vidyanagar
Corresponding Author: dhavalvyasrang@gmail.com ABSTRACT Utilization of Renewable Resources as a main stream sources of full fill the power requirements in urban and rural areas of India and the world creates the challenge for electrical engineer to develop effective control strategies for current and voltage control for micro grid operations which is presented in this paper. This paper describes use of dq theory for control micro grid at different mode of operation points which helps to achieve effective closed loop control in standalone operation of Renewable resources and also in synchronism with grid. Keywords—Distributed generation, Constant Current Control, Voltage control, PLL, PI Controller. I. INTRODUCTION An increasing development and reduce energy crisis, in electric power with the use of renewable energy sources which plays a main role for continuous power supply. Power electronics are the enabling technology to convert classical power systems into smart grids, since they allow controlling the power flows and bus voltages in the milliseconds range. AC-DC converters with bidirectional power capability are the key elements in micro grids and distributed generation systems. The different configurations of variable speed wind turbines need power converter Structures based on two AC-DC converters. Each converter needs active and reactive power control capability in order to extract the optimum power from the wind turbine while exchanging the appropriate reactive power with the power grid. Similarly, photovoltaic systems need an AC-DC inverter to inject the generated power into the grid.
Fig.1.Schematic diagram of the Micro grid with Utility Grid
II.SYSTEM BLOCK DIAGRAM A.Introduction: Fig.1 shows the system diagram which micro grid with utility grid. This system block diagram consists of a micro grid and utility grid with different storage system. Under normal operation, each distributed power generation inverter system in the Micro grid usually works in constant current control mode in order to provide a preset power to the main grid. When the Micro grid is cut off from the main grid, each distributed power generation inverter system must detect this islanding situation and must switch to a voltage control mode. A controller was designed with two interface controls: 1) 2)
For grid-connected operation For intentional islanding operation
Fig.2. Schematic Diagram Of Grid-Connected form Of Operation B. Grid-connected Form Of Operation: In grid-connected Mode Of operation, ISBN-978-81-932091-2-7
193
Connected through point of common coupling. Bi-directional flow. Economic benefit by supplying excess power to main grid. Reduce fuel cost using the power from main grid during low (night) load. During grid connected operation providing a constant current output. In this mode of operation inverter is worked as a source and supplying constant active and reactive power to the load using constant current control. Figure 3 shows the current control topology. Using the current control strategy the inverter equation is as follows,
consist a PI Controller to obtain v´d and v´q as shown in figure 3.The controller output used to inverted d-q voltages as shown in equation 3.
V 2 / 3 1/ 3 Vab V 0 1/ 3 Vbc (5)
VD cos sin V VQ sin cos V (6)
Transforming equation 1 into d-q reference frame is,
The above equations defined coupled by d and q current .the current controller now de coupled so we got,
Fig.4. PLL Structure D.Islanding Form Of Operation: In this mode of operation when grid is removed from the system and only inverter is fed to supply and balanced the load. In this mode of operation constant voltage control strategy is used which as shown in Fig.5. The voltage closed loop control work as a voltage regulation by current compensation. The result of the compensator are compared with the load current and it’s fed in the PI regulator. The error is accepted to a PI controller to find out the modulation index value. The output of this is considered as a reference signal for the system.
Fig. 3.Constant Current Control Technique
C.Switch over between grid and islanded mode of Operation: The point at which the grid is disconnected and without changing in standard parameters its switch over to islanding mode. This is done by synchronous reference frame PLL which
Fig.5.Constant Voltage Control Technique III.SIMULATION ANALYSIS A. Simulation Parameters: a) Grid Parameters a. Voltage – 440 Volts RMS ISBN-978-81-932091-2-7
194
b. Frequency – 50 Hz b) Inverter Parameters a. DC Voltage – 1550 Volts DC b. Smoothening Reactor – R: 2Ω, L: 100 mH c. 3 leg inverter with 6 IGBT’s c) Load Parameters a. 3-Ph RLC Parallel Load with Y point Grounded b. Voltage – 440 Volts RMS c. Frequency – 50 Hz d. Active Power – 10,000 watt, Reactive Power – 100 VAR inductive d) LCL Filter Parameters a. L: 0.5 mH, C: 62 mF, L: 0.25mH The system is simulated in mat lab 2013. It is consisting of micro grid and utility grid both are connected parallely. Three mode of operation is here defined for this system. B. Simulation Model:
Fig.7. Voltage & Current Waveform while Inverter Supply to load 2) 0.1 to 0.2 sec - inverter synchronized with Grid and both supplying to Load:
Fig.8. Voltage & Current Waveforms while inverter + Grid supply to Load Fig. 9. 0.2 to 0.3 sec -Only Grid supplying to load(Figure-9):
Fig. 10. Voltage and Current waveform of Load Bus(Figure-10):
Fig.6. System Simulation Model C. Simulation Results: Operation Time: 1) 0 to 0.1 sec - only inverter supplying to Load 2) 0.1 to 0.2 sec - inverter synchronized with Grid and both supplying to Load 3) 0.2 to 0.3 sec - only grid supplying to Load 1) 0 to 0.1 sec -Only Inverter supplying to load:
Fig. 11. Voltage and Current waveform of Inverter Bus(Figure-11):
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Fig. 12. Voltage and Current waveform of Grid Bus(Figure-12):
d) P - watt and Q – var Balanced while power supplying by Grid to Load e) Voltage and Current Balanced while power supplying by inverter + Grid to Load f) P - watt and Q – var mismatch while power supplying by inverter + Grid to Load
Fig. 13. Active Power Measurement(Figure13
Fig. 14. Reactive Power easurement(Figure14):
D. Result Analysis: a) Voltage and Current Balanced while power supplying by inverter to Load b) P - watt and Q – var Balanced while power supplying by inverter to Load c) Voltage and Current Balanced while power supplying by Grid to Load
IV.CONCLUSION As per describe control strategy, voltage and current remains constant for 440v,50Hz system for varying load condition and three different mode of operation for micro grid system model. Moreover active and reactive power supply and demand also matches in two out of three modes of operation and in future control logic for balancing of P & Q for third mode of operation will be develop. List of Figures 1. Figure-1 : Schematic diagram of the Micro grid with Utility Grid 2. Figure-2 : Schematic Diagram Of GridConnected form Of Operation 3. Figure-3 : Constant Current Control Technique 4. Figure-4 : PLL Structure 5. Figure-5 : Constant Voltage Control Technique 6. Figure-6: Fig.6. System Simulation Model 7. Figure-7 : Voltage & Current Waveform while only Inverter Supply to load 8. Figure-8 : Voltage & Current Waveforms while inverter + Grid supply to Load 9. Figure-9 : Voltage & Current Waveforms while only Grid supply to Load 10. Figure-10 : Voltage & Current waveforms of Load Bus 11. Figure-11 : Voltage & Current waveforms of Inverter Bus 12. Figure-12 : Voltage & Current Waveform of Grid Bus 13. Figure-13 : Active Power Waveform for Grid, Inverter & Load Bus 14. Figure-14 : Reactive Power Waveform for Grid, Inverter & Load Bus REFERANCES ISBN-978-81-932091-2-7
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1. Irvin J. Balaguer, Student Member, IEEE, Qin Lei, Shuitao Yang, Uthane Supatti, Student Member, IEEE, and Fang Zheng Peng, Fellow, “Control for Grid-Connected and Intentional Islanding Operations of Distributed Power Generation” IEEEI INDUSTRIAL ELECTRONICS, VOL. 58, NO. 1, JANUARY 2011 2. Agust Egea-Alvarez, Adri_a JunyentFerr_e and Oriol Gomis-Bellmunt “Active and reactive power control of grid connected distributed generation systems”. 3. Mr. Juan C. Vasquez, Mr. Joseph M. Guerrero, Senior Member, IEEE “Adaptive Droop Control Applied to Voltage-Source Inverters Operating in Grid-Connected and Islanded Modes”; IEEE transactions on industrial electronics, vol. 56, no. 10, October 2009 4. Sreelekshmi R S & Sunitha R “Analysis of Inverter Fed Micro-grids For Different Modes of Operation in Matlab/Simulink,” , Journal of Power System Operation and
Energy Management ISSN (PRINT): 2231– 4407, Volume-2, Issue-1, 2 5. G. Adamidis1, G. Tsengenes1 and K. Kelesidis1, “Three Phase Grid Connected Photovoltaic System with Active and Reactive Power Control Using “Instantaneous Reactive Power Theory”, International Conference on Renewable Energies and Power Quality (ICREPQ’10)
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Reactive Power Compensation using Static Synchronous Series Compensator (SSSC) [A Review Paper] Ruchirkumar Mehta, N. G. Mishra Department of Electrical Engineering, Birla Vishvakarma Mahavidyalaya Corresponding Authoor: ruchirsmehta@gmail.com ABSTRACT The power system has now a day become very complex and the load on the system is increasing rapidly resulting in a major increase in reactive power absorption. Flexible Alternating Current Transmission System (FACTS) devices are very useful in providing reactive power compensation to the system. One such device is Static Synchronous Series Compensator (SSSC). The SSSC provides series compensation to the power system through series voltage injection. This paper represents the reactive power compensation and voltage regulation obtained by SSSC in the power system. Simulation of the SSSC is carried out in MATLAB software. The control circuit comprises of d-q transformation and PI controllers. The simulated converter circuit of SSSC has a six-pulse Voltage Source Inverter (VSI) whose output AC voltage is fed into the system. The injected voltage is independent from the line current. The injected voltage (compensating voltage) can lead or lag the line current by 90° i.e. it can operate in both the inductive and capacitive region. The SSSC not only provides reactive power compensation but also voltage regulation. Key words- SSSC, Active power, Reactive power compensation, FACTS device, Voltage Source Inverter. is used instead of the DC capacitor and thus I. INTRODUCTION resistive compensation in the transmission line Today, there is need for fast and flexible power is also obtained. The SSSC controls power flow control in transmission system because flow in steady state as well as improves increase in utility deregulation and power transient stability of the power system. The wheeling requirement is expected in the future. parameters of the power system are controlled The power transmission system needs to be by PI controllers. The reactive power effectively operated and their utilization compensation of the power system will reduce degree needs to be increased by the utilities. voltage drop and provide voltage regulation in The FACTS devices like SSSC are used to the power system. The injecting voltage can prove their performance in terms of stability emulate as inductive or capacitive reactance as and reactive power compensation [1]. the injecting voltage is in quadrature with line The SSSC can control both the active and current. This paper presents mainly reactive reactive power flow in the line. The power compensation using SSSC [4]. compensating voltage is independent of the II. PRINCIPLE OF OPERATION OF line current. The SSSC can produce threeSSSC phase AC voltage at the desired fundamental Transmission line inductance is compensated frequency with controllable variable amplitude by a series capacitor by presenting a lagging and phase angle. Therefore, SSSC is having quadrature voltage with respect to the analogy with synchronous voltage source. The transmission line current. The lagging SSSC does not have sub synchronous quadrature voltage works in opposition to the resonance oscillations because it does not leading quadrature voltage across the resonate with inductive line impedance [6]. transmission line inductance. The inductive The SSSC is also analogous to synchronous reactance of the line is reduced due to the net compensator as it can both generate or absorb effect. The schematic diagram of SSSC is reactive power from the system. It can also shown in fig.1. The operation of SSSC is provide real power compensation if DC battery similar as it also injects quadrature voltage VC ISBN-978-81-932091-2-7
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which is independent of the line current but lagging in phase [5].
Where Vs and Vr are magnitudes of voltage sources and đ?&#x203A;żs and đ?&#x203A;żr are the phase angles of voltage sources Vs and Vr respectively. Assume Vs = Vr. đ?&#x203A;ż= đ?&#x203A;żs â&#x20AC;&#x201C;đ?&#x203A;żr (3) Thus, the real and reactive power equations are represented this way: P= đ??&#x2022;đ?&#x;? đ?&#x;?
đ??&#x2014;đ??Ş đ??&#x2014;đ??&#x2039;
đ??&#x2014;đ??&#x2039; đ?&#x2018;˝đ?&#x;?
Q= đ?&#x2018;ż
đ?&#x2019;&#x2020;đ?&#x2019;&#x2021;đ?&#x2019;&#x2021;
Fig. 1: Static Synchronous Series Compensator
Fig. 2: Two machine system with SSSC and the phasor diagram of SSSC Fig.2 shows Static Synchronous Series Compensator (SSSC) for a two-machine system and the associated phasor diagram. The insertion of AC output voltage of the inverter in the transmission line is performed by a voltage source inverter (VSI) and a coupling transformer. The SSSC controls the magnitude and phase angle of this inserted ac compensating voltage effectively. The transmitted power Pq is a parametric function of injected voltage. The real and reactive power (P and Q) without SSSC at the receiving end voltage are given respectively by expressions (1) and (2). đ?&#x203A;ż is the transmission angle between the two machines. P= Q=
đ?&#x2018;˝đ?&#x2019;&#x201D; đ?&#x2018;˝đ?&#x2019;&#x201C; đ?&#x2018;żđ?&#x2018;ł
đ?&#x2018;˝đ?&#x2019;&#x201D; đ?&#x2018;˝đ?&#x2019;&#x201C; đ?&#x2018;żđ?&#x2018;ł
đ??Źđ??˘đ??§(đ?&#x153;šđ?&#x2019;&#x201D; â&#x2C6;&#x2019; đ?&#x153;šđ?&#x2019;&#x201C;) = (1)
đ?&#x2018;˝đ?&#x;? đ?&#x2018;żđ?&#x2018;ł
(đ?&#x;? â&#x2C6;&#x2019; đ??&#x153;đ??¨đ??Ź(đ?&#x153;šđ?&#x2019;&#x201D; â&#x2C6;&#x2019; đ?&#x153;šđ?&#x2019;&#x201C;)) = đ??&#x153;đ??¨đ??Ź đ?&#x153;š)
(2)
(đ?&#x;? â&#x2C6;&#x2019; đ??&#x153;đ??¨đ??Ź đ?&#x153;š) =
(đ?&#x;? â&#x2C6;&#x2019;
đ??Źđ??˘đ??§ đ?&#x153;š = (4) đ?&#x2018;˝đ?&#x;?
đ?&#x;?
đ?&#x2018;żđ?&#x2019;&#x2019; đ?&#x2018;żđ?&#x2018;ł
đ?&#x2018;żđ?&#x2018;ł
(đ?&#x;? â&#x2C6;&#x2019; đ??&#x153;đ??¨đ??Ź đ?&#x153;š)
(5) When the SSSC is operated in the inductive mode the compensating reactance Xq is defined to be negative and in the capacitive mode compensating reactance Xq is defined to be positive. Xeff is the effective reactance of the transmission line including the variable compensating reactance inserted by the injected voltage source of the SSSC [3]. III. CONTROL STRATEGY The specifications and model parameters are given below in table 1. There are four buses in the given power system B1, B2, B3 and B4 connected in the ring mode. Two power plants supplies phase-to-phase voltage 13.8 kV to the power system. The transmission line voltage is of 500 kV. The lengths of the transmission lines Line1, line2, line3 and line4 are 150 km, 280 km, 150 km and 50 km respectively. Table 1: Specification and parameters of model Specifications System parameters Generator G1 or Machine M1 Generator G2 or Machine M2 Transformer TR1 Transformer TR2
đ?&#x2018;żđ?&#x2018;ł
đ?&#x2018;żđ?&#x2019;&#x2020;đ?&#x2019;&#x2021;đ?&#x2019;&#x2021;
đ??Źđ??˘đ??§ đ?&#x153;š
đ??Źđ??˘đ??§ đ?&#x153;š đ?&#x2018;˝đ?&#x;?
đ?&#x2018;˝đ?&#x;?
System phase to phase voltage
2100 MVA, 13.8 kV 1400 MVA, 13.8 kV 2100 MVA, 13.8 kV/ 500 kV 1400 MVA, 13.8 kV /500 kV 13.8 kV
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Transmission line voltage Load Base parameters
Line length
500 kV 2000 MVA Base voltage= 500 kV Base power= 500 MVA Line1= 150 km, Line2=280 km, Line3= 150km, Line4= 50 km
Fig. 3: Control system of SSSC The above fig. 3 shows the control system of the SSSC. First, line voltage V and line current I both from the bus are measured for controlling the power flow in transmission line. Active power Pact along with reactive power Qact is calculated using values of line voltage V1 and line current I1. Feedback signals of the control loop utilizes these calculated active and reactive power. Pref and Qref are the ideal reference values provided for the system. Pact and Qact are compared with the reference values Pref and Qref. The error signals obtained from this comparison are then forwarded to PI controller. The PI controller reduces the steady state error and eliminates inaccuracy of the signals. The error is reduced to its least possible values of signals and it is made sure that actual calculated values Pact and Qact match with the reference values Pref and Qref. Thus power flow control is attained. These controller results are then converted to abc reference and forwarded to the pulse width modulator (PWM).
Fig. 4: Simulated converter circuit of SSSC The expressions of the calculated actual values of real and reactive powers Pact and Qact are given below: Pact = Vd*Id + Vq*Iq (6) Qact = Vq*Id + Vd*Iq (7) Six high frequency signals are produced by PWM. Control to the switches of Voltage Source Inverter is provided by these signals. The voltage source inverter (VSI) produce three phase voltages using these signals. These three phase voltages are injected into the transmission line through series transformer. Transmission line current is in quadrature to this injected voltage. As shown in above fig.5, active and reactive power can be fed or absorbed using the compensator provided with a DC voltage source in the converter circuit. The SSSC converter circuit works along with the control circuit [2,3]. IV. SIMULATION OF SSSC The two machine power system without SSSC and with SSSC both are represented in fig.5 and fig.6 respectively.
Fig. 5: Two machine power system without SSSC ISBN-978-81-932091-2-7
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Fig. 6: Two machine power system with SSSC
Fig. 7: Active and reactive power at bus 3 for system without SSSC (in p.u. value) The results of the without SSSC power system and with SSSC power sytem are shown in fig.7 and fig.8.
Fig. 8: Active and reactive power at bus 3 for system with SSSC (in p.u. value) From fig.8 and fig.9, it is observed that SSSC increases the active power and does reactive power compensation. The active power is increased to 0.78 p.u. and reactive power is compensated from 0.42 p.u. to 0.40 p.u. at bus 3 of the power system. V.
The SSSC can effectively compensate the reactive power of the power system. The reactive power absorption at The active power flow is also increased from 0.55 p.u. to 0.78 p.u. The SSSC can also be used for multimachine power systems. Active power and reactive power both can be controlled by SSSC. The SSSC can also provide improvement in the voltage profile of the power system. The SSSC also provides stability to the power system. REFERENCES 1. Mohammed abdul khader aziz biabani, Mohd akram, Ikram ahmed shareef, “Power System Stability Enhancement using Static Synchronous Series Compensator”, International conference on Signal Processing, Communication, Power and Embedded System (SCOPES)2016, IEEE. 2. Pooja Nagar, S. C. Mittal, “Reactive power compensation by Static Synchronous Series Compensator”, 2016 International Conference on MicroElectronics and Telecommunication Engineering. 3. H. Taheri , S. Shahabi , Sh. Taheri , A. Gholami , “Application of Synchronous Static Series Compensator (SSSC) on Enhancement of Voltage Stability and Power Oscillation Damping”, IEEE 2009. 4. M. Faridi, H. Maeiiat, M. Karimi ,P. Farhadi, H. Mosleh,”Power System Stability Enhancement Using Static Synchronous Series Compensator (SSSC)”, Islamic Azad University-Ahar Branch, Ahar, Iran, IEEE 2011. 5. Narain G. Hingorani, Laszlo Gyugyi, “Understanding FACTS: Concepts and Technology of Flexible AC Transmission Systems”, IEEE Press, A John Wiley & Sons, Inc., Publication. 6. Abdul Haleem, Ravireddy Malgireddy, “Power Flow Control with Static Synchronous Series Compensator (SSSC)”, Proc. of the International Conference on Science and Engineering (ICSE 2011).
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Induction Motor Protection System Using Fuzzy Logic Nirav M. Dudhat, Akshay A. Pandya Department of Electrical Engineering, BVM Engineering College, Vallabh Vidhyanagar, Gujarat. Corresponding Author: niravdudhat999@gmail.com AbstractIn this paper the protection of three phase induction motor is simulated using fuzzy logic. Mainly in system there are two types of faults which are electrical and mechanical fault. In mechanical faults broken rotor bar, mass unbalance, air gap eccentricity, bearing damage, rotor winding failure, and stator winding failure are there, where as in electrical faults unbalance supply voltage or current, single phasing, under or over voltage or current, reverse phase sequence, earth fault, overload is there. From that six faults are taken in this paper, which are over voltage, over current, voltage and current unbalance, low voltage and temperature rise. When any of the fault is detected then the delay time is computed by fuzzy logic. If the fault is not cleared after this time delay the system will send stop signal to motor. In the conventional protection system, the time delay is predefined for various faults without considering the fault level. If any temporary failure is detected in the system, motor should not stop. Similarly, if the system waits too long to stop motor in critical faulty condition then it will lead to the serious defect. So, it is necessary to set time delay optimally. By fuzzy logic the time delay is computed on the basis of fault level which was not considered in the conventional protection system. In this paper different time delays are computed for various faulty parameters. The time delay is obtained according to rule base. This proposed system is effective and more reliable. Keywords: Fuzzy logic, induction motor, motor protection, Simulink model. I. INTRODUCTION In the modern era of industrialization, the most essential part of the industries is electrical motor. Mainly electrical motors types are AC and DC. In AC motor fractional hp motors are used in different home appliances and giant synchronous and induction motor are used widely in industrial applications which are up to 10,000 hp. It should be protected against different electrical and mechanical faults for serving their purposes smoothly. So it is necessary to select the proper protection by using the motor characteristic curve. Induction motor is widely used in industrial application because they are rugged, low cost, low maintenance, reasonably small sized reasonably high efficient, and operating with an easily available power supply. They are more reliable in operation but they are more subjected to different types of undesirable faults. Mainly Over voltage, over current, temperature rise, low voltage, voltage unbalance and current unbalance this type of fault occurs normally in induction motor. This fault can be detected by
mechanical or electrical failures, signal processing and artificial intelligence techniques. In the conventional methods that detects mechanical failures of induction motor by means of mathematical models used one or more of the stator current, speed, vibration level or winding temperature values however, these methods may be insufficient for complex and nonlinear error conditions that cannot be modeled mathematically Artificial intelligence methods are useful in this type of problems. Artificial neural networks, fuzzy logic, genetic algorithms and their hybrids are known as soft techniques. In conventional protection techniques relays are provided with some time delay time without considering the fault level while in case of fuzzy logic the time is calculated as per the fault type and required step will be taken in between 0 to 4.5 sec time span. If fault persist after that that motor will stop.
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The human decision-making process can often be implemented in complex systems with more success than conventional control techniques with use of this intelligence method like fuzzy logic. In fuzzy logic the fuzzy rule base is created on the bases of experience, observation and mathematical equation. If the created rule base is well and comprehensive then results will be accurate and precise. In this paper, the delay time is achieved which is used for stopping motor if the fault is not cleared after this delay time. The characteristics of motor which is used for the proposed system are listed in Table 1. The values in Table 2 are used for preparing fuzzy rule base. Limit values are selected in accordance with NEMA standards and TS-3205 EN 60034-1 numbered standard of TSI (Turkish Standards Institution). Table I. Motor Parameters Voltage : 230/380 V Speed : 1500 rpm 2.2kW induction Current : 5.3A motor Torque : 16 Nm Efficiency : 81% Table II. Limiting Values Parameters Min Set Max Value Set Value
Unit
Over Voltage
240
>270
V
Over Current
5.5
>8.4
A
Temperature
135
>155
˚c
Voltage Unbalance
20
>50
V
Current Unbalance
0.5
>2
A
Low Voltage
200
<160
V
Time (Output)
0
4.5
Sec
Figure1. Fuzzy Control System The two separate rule base are created by dividing six different input values to reduce the processing time and size of fuzzy system as shown in figure 1. Here the fuzzy expressions have three membership levels which are lowmedium-high. If six inputs are not divided in two groups then the number of rules will be 36= 729. By dividing the inputs, rules are reduced to 126. Some samples of the rule base used in protection system model are shown in the following Table 3 and Table 4. Where NA shows that this particular error did not occurred in induction motor. TABLE-3.1ST Rule Base Sample Rule Over Over Temperature Time No. voltage current delay
1 2 3 4 5 6 7 8 9 10
OVL OVL OVL OVL OVM OVH OVL OVL NA OVL
OCL OCL OCM OCH OCH OCL OCM NA OCL NA
TL TM TH TL TH TL NA TL TL NA
VL VL N LN VS LN LN VL VL LN
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11
NA
OCM
NA
N
Table-4 2ND Rule Base Sample
Rul e No.
Voltage Unbalan ce
Current Unbalan ce
Low Voltag e
1 2 3 4 5 6 7 8 9 10 11
VUL VUL VUL VUL VUL VUL VUL VUM VUL NA VUL
CUL CUL CUL CUM CUM CUM CUH CUM NA CUL NA
LVL LVM LVH LVL LVM LVH LVL NA LVL LVL NA
Tim e Dela y VL VL LN VL LN N LN N VL VL LN
II. Simulink model Simulink model used in the paper is shown in the figure 2. In the Simulink model of system block function consists, Min–Max: Simulink blocks for to get Minimum and maximum of input values Mux: Simulink blocks to multiplex input
nodes of blocks that have one input (Multiplexer) Fuzzy logic controller 1,2: Simulink block includes fuzzy logic design. This block calculates the time values and transfers it to next block.
Figure 2. Simulink Model of the System Display: shows the minimum one of the calculated time periods. Voltage-Current Unbalance: Compares input values and give the biggest one of the differences as result. To do this, three inputs are subtracted from one another and the biggest absolute result considered as the final value. Internal structure of this block is given in figure3 Voltage 1-2-3: 3 phase supply voltage. Current 1-2-3: Input current of three phases Temperature: Input for winding temperature of motor. Here, the figure 4 and 5 shows the membership functions of the over voltage and output delay time accordingly. For over voltage there are three membership functions which are Over Voltage Low (OVL), Over Voltage Medium (OVM) and Over Voltage High (OVH). Similarly, for the delay time 5 membership ISBN-978-81-932091-2-7
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functions are Very Long (VL), Long (LN), Normal (N), Short (s) and Very Short (VS).
Figure 3. Voltage Unbalance Block
Figure 4. Membership Function for Over Voltage
Figure 5. Membership Function for Delay Time III. SIMULATION RESULT In this study, the fuzzy logic based flexible protection system was implemented for induction motor. The Simulink model was
developed for simulating the delay time for different operating conditions. The input clusters and fuzzy rule bases have been entered in to FIS GUI, fuzzy logic toolbox of MATLAB. The results are produced by using two rule base which is given in Table 5 and 6. TABLE5. Some Results for Rule Base 1. Rul Over Over Temperatu Dela e Voltag Curre re y No. e nt (˚c) Tim (V) (A) e (s) 1 260.9 8.5 155.2 1.33 2 256.8 8.8 NA 2.26 3 246.6 NA 138.2 3.58 4 NA 8.6 155.5 1.27 5 278.4 NA NA 2.25 6 NA NA 153.8 1.65 TABLE6. Some Results for Rule Base 2. Rul Voltage Current Low Dela e Unbalan Unbalan Voltag y No. ce ce e Tim (V) (A) (V) e (s) 1 23.8 0.9 192.5 3.58 2 30.9 1.6 186.2 2.92 3 37.6 1.5 NA 2.45 4 NA 2.6 168.8 1.5 5 NA NA 182.1 2.71 III. CONCLUSION In this paper, a fuzzy logic-based protection system is used for detecting the faulty operations of three phase induction motor. A Simulink model was implemented for protecting the motor from over voltage, over current, low voltage, current and voltage unbalance and temperature rise. When any error is detected, the system waits for certain time and then stops induction motor if fault is not recovered. In mechanical protection relays, this delay time was adjusted manually but this proposed protection system produces delay time according to fuzzy logic for different degree of various error combinations. So the flexible and optimal delay time is ISBN-978-81-932091-2-7
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obtained and this methodology is accurate and easy to implement. REFERENCES [1] O. Uyar and M. Çunkaş, 16-18 May 2011. “Design of Fuzzy Logic Based Motor Protection System”, In: 6th International Advanced Technologies Symposium (IATS’11), Elazığ, Turkey. [2] Weidman Qi, a, Jie Xiao, and Youhan Deng, 2015.“Induction Motor Protection System Based On Fuzzy Logic”, In: Applied Mechanics and Materials Vols 719-720 (2015) pp 584589.Trans Tech Publications, Switzerland. [3] Pedro Vicente Jove Rodríguez, 2008. “Detection of Stator Winding Fault In Induction Motor Using Fuzzy Logic”, Elsevier Science. [4] Priyanka Nath, Jamini Das, Abdur Rohman, Tapan Das, April 6-8, 2016. “A Fuzzy Logic Based Overcurrent Protection System for Induction Motor”,In: International Conference on Communication and Signal Processing, India. [5] Okan Uyar, Mehmet C¸ unkas, 2012. “Fuzzy logic-based induction motor protection system”, Springer-Verlag London. [6] Mr. Chavan Mayur D, Mr. Swami P.S, Dr. Thosar A.G, Mr. Gharase Rajendra B., Dec 2013. “Fault Detection of Induction Motor Using Fuzzy Logic”, In: International Journal of Engineering Research & Technology (IJERT). ISSN: 2278-0181.
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A Review Paper on Fuzzy Logic Based Speed Control of Induction Motor Vishal R. Patel, Akshay A. Pandya Department of electrical engineering, BVM Vallabh Vidhyanagar Gujarat, India Corresponding Author: vrp1694@gmail.com Abstract: Induction motors are designed to work for constant speed application, many industrial applications require wide range of speed control of induction motor. Fuzzy logic-based speed controller for induction motor provides large range of speed control compared to conventional controllers. This paper presents the study of Fuzzy logic-based speed controller for induction motor. Error signal and change of error signals are the two inputs to Fuzzy logic controller, which performs 49 if-then rules inference on that signals and generates control signals which are fed to inverters. The control signals obtained from fuzzy logic controller (FLC) drives the GATE pulses of inverter which indeed changes the output voltage of the inverter according to change in speed. The results obtained from this approach are compared with conventional controller like PI controllers. Keywords: Induction motor, Fuzzy logic controller, Inverter 1. Introduction Induction motors have gained popularity in industrial applications due to their low maintenance, robust construction, high starting torque and cost effectiveness. Induction motors are designed to have constant speed. But in some cases their speed needs to be controlled. Such cases are (1) when the induction motor is started with no-load; at the time of starting it draws more current from supply which is 6-7 times higher than the rated current. Since no load is connected to motor it runs at very dangerous speed which may damage the motor. (2) In some situation the motor needs to drive the load whose speed may be greater than or less than the rated speed of induction motor. So, in these situations instead of installing a new machine it is better to control the speed of existing machine. The speed of induction motor can be controlled from stator side as well as from rotor side. Most common methods used for speed control are V/F control and vector control method. These methods are implemented using controllers in industries. The most popular controller among all industries is PI controller, because they are easy to design and their low cost. The only
problem associated with PI controller is that the design complexity increases with non-linearity of Induction motor. Hence non-conventional controller like Fuzzy logic controller can be used to overcome this problem. 2. Fuzzy logic control After the discovery of fuzzy set theory by L. Zadeh in 1965, it has gained popularity in last 3 decades. In first few years, it was just a theoretical concept but in recent years engineers have started to use this approach in real word application. Fuzzy logic controllers follow the fuzzy set theory and it has three basic functions which are as follows… (1) Fuzzification: The fuzzification module converts the crisp values of the control inputs into fuzzy values, so that they are compatible with the fuzzy set representation in the rule base. (2) Rule base: The rule base is essentially the control strategy of the system. It is usually obtained from expert knowledge or heuristics and expressed as a set of IF-THEN rules. The rules are based on the fuzzy inference concept and the antecedents and consequents are associated with linguistic variables. ISBN-978-81-932091-2-7
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(3)
Defuzzification: The mathematical procedure of converting fuzzy values into crisp values is known as ‘Defuzzification’. There are four methods are available for defuzzification. However, the choice of defuzzification depends upon the application and available processing power. 3. Fuzzy logic controller in MATLAB MATLAB provides users with built in function of Fuzzy logic controller. It can be accessed by using the command “fuzzy” in command window. The fuzzy logic controller window consists of input block, output block and controller block as shown in the following figure 1. Designer may choose more than one input and more than one output at the same time. The input and output blocks consist of membership functions of the given system. The designer may choose from various membership functions depending upon his needs, however most commonly used membership functions are Triangular and Trapezoidal membership function. The rule base of the controller consists of number of IF-THEN rules, which are designed according to inputs and outputs of the system. The rules designed in controller are in linguistic form; hence, it is easy for any operator to understand.
Figure 1: Fuzzy logic controller editing window 4. Simulation for the proposed scheme The speed control of induction motor using fuzzy logic controller can be simulated using MATLAB software. Whole simulation process can be divided into following blocks.
(1) Fuzzy logic controller: Basic function of the fuzzy logic controller in this particular scheme is to generate current reference signals, which drives the inverter, and hence the input voltage to the motor can be changed according to speed of the motor. There are two inputs to the fuzzy logic controller. One is error in speed, Table 1: output table of fuzzy logic controller
which can be obtained by comparing the actual rotor speed with that of reference speed; another input is change in error. There are 7 membership functions for both speed error and change in speed error, hence total of 49 IF-THEN rules needs to be designed in controller block. The output table for the FLC is shown in figure. (2) Driver circuit for inverter: The current reference generated by the fuzzy logic controller are converted from d-q to α-β quantities using inverse Park transformation. This driver circuit generates the GATE pulses, which drives the inverter switches. (3) Inverter circuit: It consist of six power electronic switches such as IGBT, MOSFET etc. connected in bridge form. The driver circuit governs the sequential switching of the power electronic switches. The output voltage of the inverter is fed to induction motor. (4) Induction motor: For the means of simplicity, the induction motor is modeled in mathematical form. The dynamic (mathematical) model of induction motor consist of electrical sub model and mechanical sub model. The dynamic model of induction motor is shown in following fig.2.
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Rotor leakage inductance 0.002 Mutual inductance 0.041 Inertia 0.089 Number of poles 4 Table 2: induction motor parameter A 3-phase, squirrel cage, 5hp, 1500 rpm induction motor is used for the simulation.
Whole control strategy for the speed control of induction motor can be simulated as shown in the block diagram. The simulation results obtained by the fuzzy logic controller can be compared with conventional PI controller. Research says that overshoot problem arising in using PI controller for speed control of induction motor can be overcome by using Fuzzy logic controller.
The dynamic (mathematical) model of induction motor is designed with following parameters. Parameter Value Stator resistance (Rs) 0.435 Rotor resistance (Rr) 0.816 Stator inductance 0.0424 Rotor inductance 0.0417 Stator leakage inductance 0.002
5. Conclusion Fuzzy logic approach can be used to implement human thought process in real world application. Fuzzy logic controllers are easy to design and they provide wide range of control for linear and non-linear systems. The fuzzy logic controller used for speed control of induction motor removes the overshoot problems and gives better results compared to PI controller for the same system. In early years the fuzzy logic was just a theoretical concept, but now it is possible to implement these controllers to work in real word applications. References (1) Neural and Fuzzy Logic Control of Drives and Power Systems (2) P.Tripura and Y.Srinivasa Kishore Babu 2011. Fuzzy Logic Speed Control of Three Phase Induction Motor Drive (3) Dr T.govindaraj, G.divya 2014. Speed Control of Induction Motor Using Fuzzy Logic Control (4) V.Vengatesan, M.Chindamani 2014. Speed Control of Three Phase Induction Motor Using Fuzzy Logic Controller by Space Vector Modulation Technique (5) K. L. SHI, T. F. CHAN, Y. K. WONG and S. L. HO 1999. Modelling and simulation of the three-phase induction motor using Simulink (6) S. Senthilkumar and S. Vijayan 2013. Simulation of High Performance PID Controller for Induction Motor Speed Control with Mathematical Modeling
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(7) V. Chitra, and R. S. Prabhakar 2006. Induction Motor Speed Control using Fuzzy Logic Controller (8) Atul M. Gajare, Nitin R. Bhasme 2012. A Review on Speed Control Techniques of Single Phase Induction Motor (9) Divya Asija 2010. Speed Control of Induction Motor Using Fuzzy-PI Controller
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Renewable Energy Resources with Internet of Things Himanshu Swarnkar, Shiv Lal Government Engineering College Banswara, India 327001 Corrrespondig Author: himanshu.swarnkar23@gmail.com Abstract: This paper introduces the new way of using the internet of Things in renewable energy resources in smart city like smart buildings, smart hospital, smart traffic, smart factories and transportations. All of above smart services are expected to run without any interruptions by using help of smart energy and electrical power grid. To maintain the services of smart cities run without interruption Internet of Things and cloud computing are very important in such transfers. The paper presents the role of Internet of Things (IoT) in renewable energy resources association in electricity grid. Key words: Internet of Things, Smart Grid, Cloud Computing HAN, BAN, IAN. I.
INTRODUCTION
The traditional host of World Wide Web text, pictures, audio, and video are incorporating to the physical host that providing user to control physical objects. Home Things, remote CCTV cameras floors of factory are monitors and controlled suing the Internet of Things (IoT) as media of communication. The physical web is concept is adapting nowadays. For example, to control energy in buildings an internet of Things are use [1]. This paper in introduce the IoT based experimental prototype which save the energy and provide the positive impact. For communication between consumers and utility command points to exchanges energy and electrical consumption, smart meters are use [2]. This paper extended to smart gas meters and smart water meters. In this paper we provide the guideline for utilization of smart meters in smart energy monitoring and control systems. Figure 1 shows the wide image of how power and energy from an essential part of smart cities [3]. . As illustrates in [3] real time operation data from different objects like smart electricity, water and gas meters, smart surveillance, smart transportation, smart waste management and smart environment systems are collected. After it the data is provided to a smart cluster Head (SCH) and then transmits this data to local smart fusion nodes (SFN). As a result, IoT based smart
decision is taken and control enabler center collects and interchange the data for monitoring and controlling this architecture [3]. A smart grid having mainly three layers, which are system of systems, communication networks and applications, layers [4-8]. Many literatures illustrate the popular renewable energy resources are solar energy, wind energy and hydroelectric energy [6-9]. II.
Mechanism of Internet of Things
Nowadays this world is moving to more interconnectivity and more conductivity. It has become an integrated global community using multiple technologies and various area of applications and services. IoT concepts are moving to a word where real, digital and imaginary thing are converging to makes our cities smarter and more intelligent. Traditional web technology is empowered by IoT to connect physical objects (Things) such as home appliances and smart grid Things with a unique address form each device [10-11]. This has been possible by using the IPV6 protocol which has 2128 IP address as compared to IPv4 protocol which contains 232 IP addresses. By using IPV6 ISBN-978-81-932091-2-7
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billions of Things are connected, monitored and controlled at the same time [12-14]. Due to popularity of IoT nowadays, professional of industrial and academics are divided it into two part or categories one is Consumer Internet of Things (CIoT, also IoT) and Industrial Internet of Things (IIoT) [15-16]. The most popular application are smart phones, wearable, TVs and appliances and most popular IIoT applications are smart factories, grids, machines, cities and cars. Following figure shows IoT and IIoT popular application.
III.
Propose Protocol
Consumption Domain is one of the domains of National Institute of Standard and Technology (NIST) smart gird conceptual model. Consumption domain is essential and primary candidate for agglomeration and installation of renewable energy resources. As illustrate in figure 3, mainly three types of consumers, which are residential, commercial and industrial. For all type of consumer renewable energy resources such solar, wind and hydro are installed. The consumption domain is divided into three different type of networks: Home Area Network (HAN), Business Area Network (BAN) and Industrial area network (IAN) [18-19].
Fig.1. The implementation concept of architecture in smart cities [3] Fig.3. Consumers with multiple network protocol [18]
Fig.2. Categories of Internet of Things [14]
In this network so many communication protocols are utilizing such as ZigBee, PLC, ZWave, WiFi, WiMax, 3G/GSM and LET. The figure number 3 represent the protocols of communication networks which use at the same time within one gird [19]. As we already mention in section II, there are two categories IoT and IIoT. This paper proposes the way of using the single network protocol to utilization of both to integrate three different consumer communication networks to the smart grid networks. ISBN-978-81-932091-2-7
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The resources of renewable energy is considered as an object and each object is the smart grid network unique IP is assigned. To monitor each object, bidirectional communication is use as control is done via its unique IP address. This proposes protocol eliminates the need multiple communication protocol in the same grid.
This paper proposes an IoT/IIoT conceptual model to integrate renewable energy resources with one common network protocol instead of using the multiple protocol. Different from the use of multiple communication protocol in the consumer communication network this paper introduce the use of single communication protocol by assigning the unique IP address to each electric grid devices as an object based on IoT. Using of single protocol is providing more reliable and scalable network which can control and manage remotely with the help of Internet. V.FUTURE WORK The propose prototype is work on consumption domain but it is also extends on distribution and generations domains of energy. REFERENCES
Fig.4. Propose Consumers Network with one network protocol utilizing Based on IoT concept.
Communication protocol 6LowPAN is use to utilize IP protocol, which is based on IPv6. This communication protocol has 127 bytes frame size which proved more space for a payload of 65-75 bytes [14]. The use of 6LowPAN communication protocol, make the network faster and scalable. Scalable feature enable the networks to add more devices and appliances such as local batteries, smart meters and home appliance, in the existing network as an object and each object have unique IP address. With this unique IP address of each object we control and monitor remotely using the internet. Furthermore, same can be extended to adding more other devices such as circuit breaker, capacitor banks, relays and phase measurements units of electricity grid. IV.
CONCLUSIONS
[1] Jianli Pan, Rajjain Sudharthi paul; Tam Vu; Abusaueed Saifullah;, Mo Sha, an Internet of Things Framework for Smart Energy in Building: Designs, Prototype and experiments, IEEE Internet of Things Journal,2015 :vol. 2, no. 6 p. 527-538. [2] Qie Sun: Hailong Li; Zhanyu Ma; Chao Wang; Javier Campillo; Qi Zhang; Fredril Wallin; Jun Guo, A Comprehensive Review of Smart Energy Meters in Intelligent Energy Network, IEEE Internet of Things Journal 2015: Vol. 3 No. 4, p. 4464-479 [3] Satyanarayana V. Nandury; Begum, Smart WSN-based ubiquitous architecture for smart cities, 2015 International Conference on Advances In Computing, Communications and Informatics, 2015: p. 2366-2373. [4] T. Adefarati; R. C. Bansal, Integration of renewable distributed generators into the distribution system: a review, IET Renewable Power Generation, 2016, Vol. 10, No. 7, p. 873- 884. [5] Ma Yiwei; Yang Ping; Guo Hongxia; Zeng Jun, Development of distributed generation ISBN-978-81-932091-2-7
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system based on various renewable energy resources, 4th International Conference on Power Electronics System and Application(PES), 2011, p. 1-5. [6] Wencong Si; Jianhui wang; Jaehyung Roh, Stochastic Energy Scheduling in Microgrids with Intermittent Renewable Energy Resources IEEE Transactions on Smart Grid 2014; Vol. 5 No. 4 p. 1876-1883. [7] S. Surender Reddy, P.R. Bijwe, Day-Ahead and Real Time Optimal Power Flow considering Renewable Energy Resources, International Journal of Electrical Power and Energy Systems, 2016; Vol. 82, No 11., p. 400-408. [8] Abraham Debebe woldeyohannnes, Dereje Engida woldemichael, Aklilu Tesfamichael Baheta, Sustainable renewable energy resources utilization in rural areas, Renewable and Sustainable Energy Reviews, 2016: Vol. 66, No. 12. P. 1-9. [9] Aras Ahmadi, Ligia Tiruta-Barna, Enrico Benetto, Florin Capitanescu, Antonino Marvuglia, On the importance of intergratomg alttternative renewable energy reeesources and their life sycle networks in the eco design of conventional drinking water plants, Journal of Cleaner Production 2016: Vol. 135, No 11, p. 872-883. [10] Mohsen Hallaj Asghar; Atul Negi; Nasibeh Mohammandzadeh, Principla application and vision in Internet of Things(IoT), International Conference on Computing, Communication and Automation, 2015: p. 427-431. [11] Steven E. Collier, the Emerging Internet: Convergence of the Smart Grid with the Internet of Things, IEEE Rural Electric Power Conference, 2015: p. 65-68. [12] John Pickard; Annie Y. Partick; Andrew Robinson, Analysis of enterprise IPv6 readiness, southeast Conference 2015, year 2015 Pages 1-7.
[13] Jonghwan Hyun; Jian Li; Hwankuk Kin; Jae Hyoung Yoo; James won-ki Hong, IPv4 and IPv6 performance comparison in IPv6 LTE network, the Asia-Pacigic Network Operations and Management Symposium, 2015, p. 45-150. [14] Gonnot, T. and Saniie, J., User Defined Interaction between Devices on 6LowPAN Network for Home Automation. IEEE International of Technology Management Conference, 2014: P. 1-4. [15] Designing the Industrial Internet of Things, http:// electronicdesign.com/industrial/designinginsustrial-internet-things, Accessed 30 July, 2016. [16] Hisashi Sasajima; Toru Ishikuma; Hisanori Hayashi, Future IIOT in process automationLatest trends of standardization in industrial automation , IEC/TC65, 54th Annual Conference of the society of Instument and Control EnGineers of Japa (SICE), 2015: p. 963-967. [17] National Institute of Standard and Technology. NIST framework and roadmap for smart grid interoperability standard, release 1.0, http:// www.nist.gov/public_affairs/releases/upload /smartgird_interoperability_final.pdf. January 2010. [18] B. Al-Omar, AR Al-Ali, R Ajmed, T Landosli, Role of information and communication technologies in the smart dtid, Journal of Emerging Trends in Computing and Information Science, 2012, Vol. 3, No. 5,p. 707-716. [19] Ye Yan; Yi Qian; Hamid Sharif; David Tipper, A Survey on Smart Grid Communication Infrastructures: Motivations, Requirements and challenges, IEEE Communications Survey and Tutorials, 2013: Vol. 15, No. 1, p. 5-20.
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Renewable Energy Options and Possibilities to develop Banswara as Energy Hub: A theoretical approach Shiv Lal, Shulbha Kothari Government Engineering College Banswara Corresponding Author: shivlal1@gmail.com
Abstract Energy production from renewable energy option is a sustainable approach. The manuscript is presenting the Banswara can become a renewable Energy Hub for India. Therefore, research in the field of solar, wind, biodiesel, micro-hydel and algae area can be done as resource area and for implementing the all renewables in Banswara division. the most efficient PV cell today has less than 50% electricity conversion efficiency. [3]. The 1. Introduction working efficiency of PV cell is depending The energy is the primary need of human being and the high-grade energy (Electrical Energy) is upon the weather quality, number of clear sky being utilized for many household and days, atmospheric temperature, humidity and industrial applications. Conventional and nonwind speed also. conventional methods are two methods by India is ready for biodiesel revolution. As per which energy can produced. The coal based the [4] government of India is working on thermal power plants are the major contributers nationalized biodiesel mission. India shall be of conventional energy (approximately 68% of produced biodiesel at commercial stage on or total energy production). The conventional before the end of 2006; one biodiesel plant is energy resources like coal, diesel, petrol etc. are ready for production situated at Nalgonda in limited and will be vanished in next few years. Andhra Pradesh state. The renewable energy is the sustainable option The aim of the above given mission is that the for electrical energy production and whole use of 20% blended biodiesel (B20 means 20% world is continuously working on to increasing biodiesel and 80%diesel) will be started on the production percentage though RES. The commercial stage till 2011-12. The government sustainable development of the human society will be saved the sum of Rs20, 000 crores and is directly linked with the renewable energy gives the employment to atleast 2 crore peoples. options. [1] A minimum wind which required for the power Table 1: Acquiring land for agriculture of generation is available in the region of Jatrofa [4] Banswara.), 750kW and 1 MW wind mills are S.NO. STATE AREA (in situated in wind farms of India. The wind Hectare) energy power generation mills are available in 1 Rajasthan 275 various design features according to the number of blades, power generation capacity, implant 2 Madhya Pradesh 260 according to the wind flow available, shaft 3 Gujarat 240 alignment and design of blades. [2] 4 Utter Pradesh 200 A photovoltaic cell is use to convert solar irradiance in to electricity. The best temperature 5 Chhattisgarh 190 for generation of electricity is 15-35 degree 6 Maharastra 150 Celsius. Temperature more than 40 degree Celsius is not utilized for power generation, 7 Harayana 140 causing a decrease in their efficiencies. Even ISBN-978-81-932091-2-7
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Today the action plan of India is targeted on Jatrofa because its research is likely to be completed. So many oils can be used for manufacturing (blending) biodiesel, Thumba oil is one of the oil which found in western Rajasthan (India) and which is very familiar to use in soap manufacturing. Another important seed oil produced in abundant quantity in India are Soya oil, Sunflower oil, Mustered oil, Rice oil, Jatropha oil, Ratanjot oil, Thumba oil, Rapeseed oil, etc. The biodiesel can also be produced from algae and so many researchers have worked on algae. [5-11] There are 112 lakes in this area and the area is hilly so the possibility of micro-hydel power plants. Almost the whole area is irrigated by canals. The mahi dam is Third Biggest Dam in India. Various designs of hydro-power generation plants are accessible in the market. So the selection of the micro-hydel power plant. [12-16] This manuscript is presented the scope and feasibility of renewable energy sources in Banswara. Because Banswara is a lush green region and abundant of water is found in the same area. Banswara is known as cherapunji of Rajasthan.
2. 2.1
Fig. 1. Geographical map of India Fig. 2 Geographical map of Banswara [google earth] It has more than 112lakes and so many small islands are situated between the lakes, thatswhy it is called as city of hundred islands. One of the example of bunch of islands is called “Chachakota” It is sited at backside of Mahi Dam which is shown in different views in Fig. 3[17]
Material and Methods About Banswara
Banswara is a district is situated between 23.11° N to 23.56° N latitudes and 73.58° E to 74.49° E. longitudes in Rajasthan state of India. Fig. 1-2shows the geographical view of Banwara on the google earth map. The state of Banswara was founded by Maharawal Jagmal Singh. And It is named for the "bans" or bamboo forests in the area. [17]
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Banswara city is governed by City Council (Nagar Parishad) which comes under Banswara Urban Agglomeration. The city has population of 100,128, its urban / metropolitan population is 101,177 of which 51,941 are males and 49,236 are females. [www.wikipedia.org] . The Banswara is situated at southern region of Rajasthan and its area is 5037 square kilometers and located between 23.11° N to 23.56° N latitudes and 73.58° E to 74.49° E. longitudes. The climate of Banswara is milder than the desert regions in further north and north-west. Maximum temperature is 45 degrees Celsius to 46 degrees Celsius. Minimum temperature is 10 degrees Celsius to 20 degrees Celsius Normal annual rainfall is 922.4 mm The main tourist places in Banswara are as follows: Andheswar Parshwanathji, Anekant Bahubali Temple, Abdullah Pir, Anand Sagar Lake, Arthuna Temples, Dailab Lake, Madareshwar Temple, Mahi Dam, Mangarh Hill, Parheada Temple, Bhim kund, Talwada, Mata Tripura Sundari Tample, Kagdi Pick-up weirs. The total transformer capacity in the district is 63.1 MV·A. of the 1,431 villages 1,219 villages were electrified up to 31 March 2000.
2.2 Power generation from Renewable Resources in Banswara Region 2.2.1 Wind Power Generation The India is producing thousands of MW energy from wind. The table 2 shows the global wind power generation and 18,212.6 MW power is generated or project under construction in India and the official capacity as on 2016 is 28,279.0 MW. [18]. According to the below table, India is in the third number for wind power generation (operational and under construction plants) Table 2. List of countries included for wind power generation [18] Fig. 3. Chachakota at Banswara[17]
Country
Database capacity Official capacity (MW) (MW) ISBN-978-81-932091-2-7
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Operational or WWEA values under construction Albania 150.0 42.0 (2016) Algeria 10.2 10.2 (2016) Argentina 1,121.5 279.0 (2016) Armenia 2.6 2.6 (2016) Australia 6,363.0 4,326.0 (2016) Austria 2,551.5 2,632.0 (2016) Azerbaijan 54.9 2.2 (2016) Bangladesh 0.9 1.9 (2016) Belarus 3.4 3.4 (2016) Belgium 2,927.8 2,386.0 (2016) Bolivia 27.0 27.0 (2016) Brazil 12,769.9 10,800.0 (2016) Bulgaria 637.5 691.0 (2016) Canada 12,782.7 11,898.0 (2016) Cape Verde 27.9 25.5 (2016) Chad 1.1 0.0 (2016) Chile 1,998.1 1,424.0 (2016) China 120,560.1 168,730.0 (2016) Colombia 19.5 19.5 (2016) Costa Rica 347.4 297.0 (2016) Croatia 466.0 467.0 (2016) Cuba 11.7 11.7 (2016) Curaçao 32.3 15.0 (2016) Cyprus 126.7 158.0 (2016) Czech Republic 347.9 282.0 (2016) Denmark 5,841.4 5,227.0 (2016) Dominican 280.3 135.0 (2016) Republic Ecuador 76.9 19.0 (2016) Egypt 744.8 810.0 (2016) Eritrea 0.8 0.8 (2016) Estonia 409.9 310.0 (2016) Ethiopia 324.2 324.0 (2016) Faroe Islands 18.6 18.3 (2016) Fiji 10.2 10.0 (2016) Finland 2,051.9 1,539.0 (2016) France 13,019.9 12,065.0 (2016) Gambia 0.2 0.2 (2016) Georgia 20.7 20.7 (2016)
Germany Greece Grenada Guam Guatemala Guyana Honduras Hungary Iceland India Indonesia Iran Ireland Israel Italy Jamaica Japan Jordan Kazakhstan Kenya Latvia Libya Lithuania Luxembourg Macedonia Mauritania Mauritius Mexico Mongolia Montenegro Morocco Mozambique Namibia Netherlands New-Zealand Nicaragua Nigeria Norway Pakistan Panama Peru
49,213.2 2,648.0 1.3 0.3 73.8 0.0 179.9 536.6 4.2 18,212.6 75.0 146.8 3,206.0 27.3 9,671.5 102.2 2,730.0 322.2 45.1 335.8 53.1 20.0 379.9 127.4 36.9 136.8 10.5 5,090.1 100.1 72.0 1,308.6 0.3 5.2 4,748.0 691.1 186.2 10.2 2,291.6 487.2 495.0 372.4
50,019.0 (2016) 2,374.0 (2016) 0.7 (2016) 0.3 (2016) 76.0 (2016) 13.5 (2016) 176.0 (2016) 329.0 (2016) 3.0 (2016) 28,279.0 (2016) 1.4 (2016) 118.0 (2016) 2,830.0 (2016) 6.0 (2016) 9,257.0 (2016) 72.0 (2016) 3,234.0 (2016) 119.0 (2016) 2.0 (2016) 25.5 (2016) 68.0 (2016) 20.0 (2016) 493.0 (2016) 99.0 (2016) 37.0 (2016) 34.4 (2016) 10.5 (2016) 3,709.0 (2016) 50.9 (2016) 0.0 (2016) 795.0 (2016) 0.3 (2016) 0.2 (2016) 4,328.0 (2016) 623.0 (2016) 186.0 (2016) 13.4 (2016) 873.0 (2015) 591.0 (2016) 270.0 (2016) 245.0 (2016) ISBN-978-81-932091-2-7
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Philippines Poland Portugal Puerto Rico Romania Russia Saint Kitts and Nevis Saudi Arabia Serbia Seychelles Slovakia Slovenia South Africa South Korea Spain Sri Lanka Sweden Switzerland Taiwan Tanzania Thailand Tunisia Turkey Ukraine United Arab Emirates UnitedKingdom Uruguay USA Vanuatu Venezuela
372.9 5,709.0 5,372.0 125.9 3,651.0 99.3
216.0 (2016) 5,782.0 (2016) 5,316.0 (2016) 125.0 (2016) 3,028.0 (2016) 16.8 (2016)
2.2
2.2 (2016)
2.8 9.9 6.0 3.1 5.5 2,322.2 874.2 23,348.9 129.9 6,113.9 75.1 641.0 50.0 596.3 242.4 7,303.6 939.4
0.0 (2016) 10.0 (2016) 6.0 (2016) 3.0 (2016) 3.0 (2016) 1,471.0 (2016) 1,031.0 (2016) 23,020.0 (2016) 130.0 (2016) 6,493.0 (2016) 75.1 (2016) 682.0 (2016) 0.0 (2016) 223.0 (2016) 245.0 (2016) 6,081.0 (2016) 559.0 (2016)
0.9
0.9 (2016)
22,119.0
14,512.0 (2016)
1,502.8 98,431.0 3.9 175.9
1,210.0 (2016) 82,033.0 (2016) 3.0 (2016) 30.0 (2016)
The Deogarh, Pratapgarh wind energy project of 126 MW is commissioned by Welspun renewables. generate 290 million units of clean energy and help mitigate 2,11,922 tonnes of carbon emissions annually. The company claims that 7,25,760 homes will get access to clean green energy, replacing the need to source carbon based energy generation. [19]
It was established jointly by the Rajasthan Energy Development Agency (REDA) and the Rajasthan State Power Corporation. The Rajasthan State Electricity Board (RSEB) has signed a power purchase agreement with the State Power Corporation to buy power at the rate of Rs. 3.03 per unit. [20]. The Mahi basin is most suitable region for wind power generation which includes Pratapgarh, Ghatol, Kushalgarh and Ratlam Road in Banswara Division. Fig. 4 (b) Shows the typical wind mill of three blades situated in Pratagarh.
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(f) Fig. 4. Renewable Energy Options for Banswara (a) Solar, (b) Wind, (c) Micro-hydel, (d) Biomass, (e) Algae, (f) Bio-diesel from different resources
2.2.2 Biomass and Biodiesel Power Plant Among the different renewable energy sources, biomass is a versatile energy source. Rajasthan is fast catching up for tapping biomass energy. 'Policy for Promoting Generation of Electricity from Biomass 2010' had been issued for encouraging investments in the sector. Biomass based power projects with capacity of 106.3MW have been commissioned as on 31.12.2011. [21]. A 6 MW biomass power plant is also under execution in Banswara. [22]. The largest production of algae and biodiesel seeds in this area and we can increase the production of biodiesel plants in Banswara by plantation in the area where barren lands available.
2.2.3 Power from solar Energy A typical solar cell is shown in fig. 4. (a), It can be utilized to generate the electricity from solar energy and that produced energy can be utilized in both off-grid and grid connected applications. Banswara is a clean weather
region having lush green forest. It has approximately 300 clear sky days. There is no pollution means the maintenance cost related to cleaning of cells is minimum, and the temperature range between 10 to 45°C which is most suitable for PV cells. The depth of underground water is varying between 10 feet to 100 feet. Solar PV pumps can be utilized for agriculture for this region. The area is tribal area and conventional electricity is far from many villages so decentralized off-grid PV system can be utilized for many applications in this area. Thousand of MW electricity can be produced by solar PV farms implementation in this area because many thousands of areas is converted to barren lands in the Kushalgarh area.
2.2.4 Micro-hydel power plants The possibility of micro-hydel power plant is very high in Banswara. [23]. Table 3. Shows the Mahi hydel power station. It is a major hydel generating station under Rajasthan Vidhut Utpadan Nigam (RVUN’s). The generation capacity of Mahi Hydro-power generation station is 140 MW. Mahi Power House-I (2x25MW) FRL 281.5M(923ft.) Live storage capacity 65.45TMCuft
Mahi Power House II (2 x 45MW) Up Stream reservoir level 220.5M(723.5ft) Live storage capacity 1.53Million cubic(54.4MCft)
Table 3. Mahi Hydel Power Station is RVUN's major Hydel generating station situated on river Mahi near Banswara town, comprising of 2 phases of installed capacity 140MW. Unit Cost(Rs. Synchronising Stage Capacity(MW) No. Crore) Date I 1 25 22.1.1986 68 II 2 25 6.2.1986 1 45 15.2.1989 119 2 45 17.9.1989
Table 4. shows the unit-wise generation in MU from 2007-08 to 2012-13 session. The generation in 2012-13 was observed higher than ISBN-978-81-932091-2-7
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other session. Table 4. Generation Status of Majer Hydel Station Generation in MU Installe Name of d S.N 2012- 20112008- 2007Power Capacit 2010-11 2009-10 o 13 12 09 08 Plant y in MW i) Mahi-I Unit-I 25 60.773 58.083 33.427 34.759 44.984 93.451 50 25.4778 28.9011 Unit-II 25 96.398 74.016 33.293 95.095 83 17 Gross 157.17 132..09 58.9048 63.6601 188.54 Generati 78.277 1 9 83 17 6 on ii) Mahi-II 26.977 19.843 45.679 Unit-I 45 26.13 6.3258 10.7886 8 8 2 90 20.028 22.269 49.073 Unit-II 45 4.0248 10.7388 15.36 6 6 4 Gross 47.006 48.399 35.203 94.752 Generati 10.3506 21.5274 4 6 8 6 on
MC 1.5 -II MC 1.5 -III Annoopga MC ii) 1.5 rh PH-II -I MC 1.5 -II MC 1.5 -III Suratgarh MC iii) 2 MMH -I MC 2 -II Pugal PHMC iv) I P/S RD1.5 -I 620 Pugal PHMC v) II P/S 0.65 -I Dandi MC vi) Birsalpur 0.535 -I Charanwa MC vii) 1.2 la -I MC viii) Mangrol 2 -I MC 2 -II MC 2 -III Ghatol MC ix) RMC-I 0.4 -I Mahi MC 0.4 -II Ganora MC x) RMC0.165 -I II mahi Total
168228 986880 0 445440 0 0
0
279426 302940 0 0
0
110040 747850 0 0
0
0
0
409243 0 281578 135330 35100
0
141690 974250 0 123105 898050 0 947400 0 306304 449232
0.6237 0.2248 6 32
472784 690497
0.4085 0.7403 6 36
172704 114160
0.1793 0.2290 28 24
109624 567718 43 9
Table 6. Generation Status of Major Hydel Fig.5. Hydro power plant and main gate opening of Mahi Dam Fig.5 presented the photographic view of Mahi Hydro power generation station at the Dam. In regards of hydro-power generation, table 5 and 6 shows the power generation in the Rajasthan in the year of 2010-11, 2011-12 and 2012-13. Table. 5. Generation Status of MMH Power Station of RVUN
Name of S.N Power o Houses i)
20092011- 2012Rating(M 2010-11 10 12 13 W) (KWH) (KWH (KWH) (KWH) )
Annoopga MC 1.5 rh PH-I -I
0
450000
Station Generation in LU Installe Name of d S.N Power Capacit 2012-13 2011-12 2010-11 2009-10 o Plant y in MW i) RPS. Total Unit-I 43 698.406 558.090 173.808 157.680 1277.22 Unit-II 43 714.516 455.404 264.042 6 172 Unit-III 43 1111.448 974.526 693.276 483.954 Unit-IV 43 1135.956 825.756 421.872 533.058 Gross 3635.59 Generatio 3660.366 1743.996 1438.734 8 n ii) J.S. ISBN-978-81-932091-2-7
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33
Unit-II
33
99
Unit-III 33 Gross Generatio n iii) Mahi-I Unit-I 25 Unit-II
25
1114.350 889.500 536.600 342.300 0 0 1025.950 939.450 292.100 264.900 0 610.6000 946.050 634.550 565.100 2750.900 2775.00 1463.250 1172.300 0 0
50
Gross Generatio n iv) Mahi-II Unit-I 45 90 Unit-II 45 Gross Generatio n
3.
33.427 34.759 25.47788 28.90111 3 7 58.90488 63.66011 3 7 6.3258 4.0248
10.7886 10.7388
10.3506 21.5274
Conclusions
Banswara is situated at the south of Rajasthan state and it is a highest rainy area, approximately 300 clear sky days are observed in 2016-17 and pollution free environment are the major criteria for possibility of renewable energy sources. It is found that all types resources like solar, wind, water, bio-fuel are available and it is most suitable area and can be convert as power hub. Therefore, industrial area can be expanded and it increased the employment in present era. Reference: 1. Shiv Lal, S.C. Kaushik, Ranjana Hans. Experimental investigation and CFD simulation studies of a laboratory scale solar chimney for power generation. Sustainable Energy Technologies and Assessments 13 (2016) 13–22. DOI: 10.1016/j.seta.2015.11.005. 2. A. Al-Alili, Y. Hwang, R. Radermacher, I. Kubo. A high efficiency solar air conditioner using concentrating photovoltaic/thermal collectors. Applied Energy xxx (2011) xxx–xxx DOI: 10.1016/j.apenergy.2011.05.010
3.
Dainik Bhasker editor, 2005 “Biodiesel Rojgar Bhara Iendhan” Page 1&12 Dainik Bhaskar Newspaper October 23,
M. Faried, M. Samer, E. Abdelsalam, R. S. Yousef, Y.A. Attia, A. S. Ali, Biodiesel production from microalgae: Processes, technologies and recent advancements, Renewable and Sustainable Energy Reviews, Volume 79, November 2017, Pages 893-913, DOI: 10.1016/j.rser.2017.05.199. 5. Sinha, S.; Agarwal, A.K.; Garg, S. Biodiesel development from rice bran oil: Transesterification process optimization and fuel characterization. Energy Conversion and Management 2008, 49, 1248-1257. 6. Agarwal, A.K. Biofuels (alcohols and biodiesel) applications as fuels for internal combustion engines. Progress in Energy and Combustion Science 2007, 33, 233271. 7. Quaye, E.C. Energy demands in the 21st century: The Role of Biofuels in a Developing Country. Renewable Energy 1996, 9, 1029-1032. 8. Barnwal B. K.; Sharma, M.P. Prospects of Biodiesel production from vegetable oils in India. Renew. Sust. Energy Rev. 2005, 9, 363-378. 9. Freedman, B.; Pryde E.H.; Mounts, T.L. Variables affecting the yields of fatty esters from transesterified vegetable oils. Journal of the American Oil Chemists' Society (JAOCS) 1984, 61, 1638-1643. 10. Zhang, Y.; Dube, M.A.; McLean D.D.; Kates, M. Biodiesel production from waste cooking oil: 1. Process design and technological assessment. Bioresource Technol. 2003, 89, 1-16. 11. Berchmans H.J.; Hirata, S. Biodiesel production from crude Jatropha Curcas L. seed oil with a high content of free fatty acids. Bioresource Technology 2008, 99, 1716-1721. 12. Mohibullah, M. A. R. and MohdIqbal Abdul Hakim: "Basic design aspects of 4.
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13. 14.
15.
16.
17.
micro-hydro-power plant and its potential development in Malaysia", National Power and Energy Conference (PECon) Proceedings, Kuala Lumpur, Malaysia, 2004. http:// www.microhydropower.net/ Retrieved on 5 December 2017 http:// www.alternative-energy.info/microhydro-power-pros-and-cons/ Retrieved on 5 December 2017 CelsoPenche: "Layman's guidebook on how to develop a small hydro site", Published by the European Small Hydropower Association (ESHA), Second edition, Belgium, June, 1998. Dilip Singh: "Micro-hydro-power", Resource Assessment Handbook, An Initiative of the Asian and Pacific Center for Transfer of Technology, September, 2009. https://en.wikipedia.org/wiki/Banswara, Retrieved on 5 December 2017.
18. https://www.thewindpower.net/store_conti nent_en.php?id_zone=1000, Retrieved on 6 December 2017. 19. http://www.renewableenergyfocus.com/vie w/43408/welspun-renewablescommissions-126-mw-pratapgarh-windproject, Retrieved on 6 December 2017. 20. http://www.thehindu.com/2000/03/18/stori es/0418221g.htm, Retrieved on 6 December 2017 21. http://pratapgarh.rajasthan.gov.in/content/r aj/pratapgarh/en/business/infrastructure.ht ml#, Retrieved on 6 December 2017 22. http://aquathermindia.com/biomass-basedpower-plants/, Retrieved on 6 December 2017 23. http://energy.rajasthan.gov.in/content/raj/en ergy-department/rvunl/en/ourplant/hydel/mini-micro.html, Retrieved on 6 December 2017
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Design Analysis of Distribution Power Network in ETAP-A Case Study Urvi Shankar Marathe, Bhupendra R. Parekh Department of Electrical Engineering, BVM Vidyanagar, Gujrat, India Corresponding Author: urvi.s.marathe@gmail.com
ABSTRACT Electrical Power system provides essential service to consumer. This research paper deals with the simulation of One subdivision network of Baroda city is considered for simulation. Simulation is done in ETAP software & Result is observed for different loading.
Keywords: ETAP, Distribution Network, Power flow Analysis in ETAP. flow is given in this paper. Backward sweep I. INTRODUCTION gives the value of Voltage & Current at different busses by using number of iterations With rapid Urbanization, Population is & forward sweep gives composite system by increasing at urban areas; Due to this to which Imaginary part and Real part of the transfer of reliable Power supply to consumer voltages and currents can be decompose. [3] end becomes critical. This happens due to high This paper gives Monte Carlo simulation congestion of distribution lines at service ends. method; this paper gives algorithms to so, that for the reliability of power design of simulate unbalanced distribution system by distribution system in proper way becomes load flow. It considers random samples to important. POWER flow studies are used to compute results. By different system samples evaluate network steady-state characteristics. different simulation results come out. By The solution method chosen in the base of considering all results average results can be accuracy and convergence necessity. considers. For Monte Carlo simulations Distribution feeders supply unbalanced loads voltage stability index is also required this can and are not transposed. Furthermore, mutual be study by [4] Basics of ETAP simulations are impedances can be significant and aggravate studied from [5]. Some advanced technologies unbalance conditions. In addition to unbalance, which are using in present distribution system R/X ratios of distribution feeders are generally are studied from [6] & [7]. [6] explains Ring high as compared to those of transmission main unit for different ratings and with new lines. So, Distribution system requires advanced features. It includes safe ring and unbalanced load flow methods. A conventional safe plus concept of ring main units. [7] gives method for load flow analysis becomes basic parameters, which are using in single inaccurate. Power system load flow analysis is phase and three phase transformers of typical tool to check power system distribution power network. performance efficiently. In this Papers unbalanced load flow is done on II. CASE STUDY a subdivision of Baroda city distribution system. This load flow is identified by 11/0.415 KV distribution feeder of a considering similar network on distribution of subdivision of Baroda area distribution Nagpur, Maharastra[1].By considering some network, Gujarat is considered for analysis. assumptions and value of Impedances and Two supply system hosts with power Voltage ratings unbalanced load flow is done transformers to feed supply to that area and results are identified. Results differs from feeders. One supply get from Gotri to the given results are about 8%. unbalanced Subhanpura feeder and other is from Jambuva load flow methods are understood by [2], [3]. to Motibaug feeder. Load receives at voltage of 0.415KV. Below Fig 1 shows line diagram of [2] explains load flow by forward-sweep & substation under case study. This subdivision backward-sweep method, algorithms for load contains total 28 feeders in which 3 H.T ISBN-978-81-932091-2-7
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feeders and 25 L.T feeders. Distribution of feeders to both 11KV substations are assumed as per the required load which has to feed to each load. This network is divided in to three parts. First part contains primary & secondary feeders of 11/0.415KV Voltage ratings 1.
PRIMARY TRANSMISSION:-
Transmission System starts from Source voltage 220KV and end to Motibaug and subhanpura 11KV substations. This layout includes primary and secondary Transmission & Primary Distribution.
Fig 2 Secondary Distribution-1
Fig-1 Transmission and primary distribution System
2. DISTRIBUTION SYSTEM:Some feeders supply loads from source-1 that is Jambuva and other is from source-2 that is Gotri. Fig 2 and Fig 3 show the Secondary distribution system for Baroda subdivision feeder loads .Here, Transformer ratings of network is given in figure, Load is consider of 65% of Transformer KVA. As any subdivision takes Power from minimum two supplies. Some consumers will be feed by Subhanpura Substation through Motibaug 11KV feeder. This feeder will supply Power to 3- H.T consumers and 11- L.T consumers.
Fig 3 secondary Distribution-2
Some consumers will be feed by Gotri Substation through Subhanpura 11KV feeder. This feeder will supply Power to 11- L.T consumers. No H.T consumer is connected to this source. III.
ONE LINE DIAGRAM OF BARODA NETWORK:-
Fig 4, Fig5 & Fig 6 is basic layout for Power Transmission & Distribution. Fig shows the single line diagram network for Distribution system for both the sources. Frequency is considered as 50Hz & 65% load of all the supply is consider. Diagram is divided in three parts: ISBN-978-81-932091-2-7
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1. Transmission System 2. Distribution System-1 3. Distribution System-2 This part contains Primary & Secondary Transmission and Primary Distribution of Network.
consumers. No H.T consumer is connected to this source.
Fig 6 Secondary distribution system-2
IV. RESULT OF LOAD FLOW AT DIFFERENT LOADING CONDITIONS.
Fig 4 Transmission System of Network
As any subdivision takes Power from minimum two supplies. Some consumers will be feed by Subhanpura Substation through Motibaug 11KV feeder. This feeder will supply Power to 3- H.T consumers and 11L.T consumers.
Unbalanced load flow analysis has Done on 20%,50% &, 100,120% loading & PF%, Current%, load% that has fulfilled at 66KV & 11KV Buses are compared. Load flow studies are done by current injection method for unbalanced load flow method. Initially,100% load is taken. As only one subdivision is consider some supply lines at 11KV substation is not considered by open circuited circuit breaker.
Fig-5 Secondary distribution system-1
Some consumers will be feed by Gotri Substation through Subhanpura 11KV feeder. This feeder will supply Power to 11- L.T
Fig-7 Load flow at distributor-1
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higher than 50% loading and nearer to 100% load. This graph explains comparison of power factors for Subhanpura, Gotri, Motibaug & Subhanpura substations.
% Receiving Load comparison:2.
Fig 8- Load flow at distributor-2
1.
Power factor comparison :-
Fig 10 Bus load at different %loading
Fig 9 Power Factor Comparison
From Fig 9, with increase in loading Power factor improves, But it can be seen that at very less loading i.e. 20% loading. Power factor is
From Fig 5, with increase in loading receiving end buses Power improves, But it can be seen that at very less loading i.e. 20% loading. Receiving end load at bus is higher than 50% loading and nearer to 100% load. This graph explains comparison of Receiving end load for ISBN-978-81-932091-2-7
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Subhanpura, Gotri, Motibaug & Subhanpura substations
3.
Current comparison:-
.
V.
CONCLUSION
By using ETAP software load flow is done on Baroda subdivision distribution network for different loading conditions by using redial system condition and effect on power factor,receiving end Power & current is compared. We can observe that at 20% loading due to Ferranti effect effect on that loading its effect is different than other 100%,50% & 120% load conditions. REFERENCES
Fig 11 Current Comparison
From Fig 11, with increase in loading receiving end buses Current reduces, But it can be seen that at very less loading i.e. At 20% loading, Current is lower than 50% loading and nearer to 100% load. This graph explains comparison of Receiving end load for Subhanpura, Gotri, Motibaug & Subhanpura substations.
[1] Kishor Porate,K.L Thakre,G.L Bodhe,”Voltage stability Enhancement of Low Voltage Redial Distribution Network Using SVC :A case study”WSEAS TRANSACTIONS on POWER SYSTEMS. [2] G.W. Chang, H.L Wang,”A Simplified Forward & Backward sweep Approach for Distribution system Load flow analysis”,2006 International Conference on Power System Technology. [3] Mini Thomas, Rakeshranjan ,Roma Raina” Load Flow Solution for Unbalanced Radial Power Distribution using Monte-Carlo Simulation”, WSEAS TRANSACTIONS on POWER SYSTEMS [5] Kiran Natkar, Naveen Kumar” Design Analysis of 220/132 KV Substation Using ETAP” International Research Journal of Engineering and Technology (IRJET), 02 Issue: 03 | June-2015. [6] “SF6 insulated Compact Switchgear, type Safe Plus and SF6 insulated Ring Main Unit, type SafeRing 12 / 24 KV”ABB catalogue. [7] guideline for specifications of energy efficient Outdoor Type three phase and single phase Distribution Transformers”,Govt.of.India Ministry of power central authority new Delhi Aug 2008.
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Power system stability enhancement using fuzzy logic-based power system stabilizer Pargi Bhavinkumar Devjibhai, Akshay A. Pandya Department of Electrical Engineering, BVM Vallabh Vidhyanagar ABSTRACT Power system is dynamic in nature and it is constantly subjected to disturbances. It is necessary that these disturbances do not lead the system to unstable condition. Power system stabilizers(PSS) are used to enhance the damping during low frequency oscillation under these disturbances. PSS are designed using conventional and non-conventional controllers. Conventional controllers uses phase lead compensation techniques, but they provide poor performance under different loading condition. To cover wide range of conditions non-conventional controllers such as Fuzzy Logic controller can be used. This paper presents the study about PSS using Fuzzy Logic approach to enhance stability of single machine infinite bus system. Speed deviation and acceleration of synchronous machine are the two inputs to the fuzzy logic controller. The supplementary voltage signals obtained from fuzzy logic controller are given to excitation system of the synchronous machine. Results presented in this paper shows that fuzzy logic-based PSS design gives superior performance than conventional PSS. Keyword: SMIB, Power System Stabilizer(PSS), Fuzzy Logic Controller(FLC) 1.
INTRODUCTION Power systems are subjected to low frequency disturbance that might cause loss of synchronism or an sometime it’s the reason for whole system break down. The oscillations, which are in frequency range of 0.2 to 0.3hz, might be generate by the disturbance in system or sometime build up spontaneously. These low frequency oscillations are generator rotor angle oscillations which limit the power capability of the system and sometime they can break the entire system. For this reason, power system stabilizers are used to generate the supplementary control signal to damp out these low frequency oscillation(LFO). Now a days mostly conventional power system stabilizer is used to overcome these problems. The CPSS can be designed using classical methods such as eigen value, root locus, and phase compensation etc. In this paper CPSS use phase compensation where the gain setting is already fixed for some situations or some specific operations but the constant changing nature of power system makes more difficult task. So, it is more difficult to design a PSS that could give good performance in all operations. To overcome this problem fuzzy logic-based tech. suggested. Using fuzzy logic-based tech. mathematical model of system are not
necessary, easy to improve and computationally efficient. The fuzzy logicbased PSS are designed on single machine infinite bus system and compare the performance between the CPSS and FPSS. Result shows that the better performance of fuzzy logic-based power system stabilizer(FLPSS) in comparison to the conventional power system stabilizer(CPSS). 2. SYSCHRONOUS MACHINE MODEL The performance of synchronous machine connected to a large system through transmission lines. Fig 1 show the configuration of SMIB. Synchronous machine connected to infinite line can be represented as the thevenin’s equivalent circuit where Et is terminal voltage and Eb is bus voltage.
Fig. 1: General configuration of system ISBN-978-81-932091-2-7
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The above equation to describe small-signal performance is represented in schematic Fig. 1.3 From the block diagram we have
Fig. 2: Equivalent system Classical System Model: The generator is represented as the voltage E' behind Xd' as shown in Fig. 1.2. The magnitude of E' is assumed to remain constant at the pre-disturbance value. Let d be the angle by which E' leads the infinite bus voltage EB. The d changes with rotor oscillation. The line current is expressed as
Fig. 3: classical model of generator
Fig. 4: Block diagram of SMIB with classical model With stator resistance neglected, the air-gap power (Pe) is equal to the terminal power (P). In per unit, the air-gap torque is equal to the air gap power.
Solving block diagram we get char. Equation:
Compare with general form, the undamped natural frequency and damping ratio as
3. POWER SYSTEM STABILIZER The basic function of power system stabilizer is to add supplementary signal to the generator rotor oscillations by controlling its excitation using auxiliary stabilizing signals. Foe provide damping signal the must produce a component of electrical torque in phase with rotor speed deviations. The fig. shows the block diagram of PSS. The CPSS can use input as speed deviation of generator shaft, accelerating power or even the terminal bus frequency. In this paper the speed deviation is used as input and voltage signal as output of CPSS.
Fig. 5: block diagram of SMIB with PSS ISBN-978-81-932091-2-7
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4. FUZZY CONTROLLER Fuzzy logic control system are rule based system which a set of fuzzy rules present a control decision to adjust the effect of certain system simulation With the help of effective rule base we can improve our system more and control also increase. The fuzzy logic controller provide an algorithm which can convert the control strategy into automatic control strategy. Fig. shows the fuzzy logic controller which consists of a fuzzification interface, a knowledge base, control system, decision making logic. And a defuzzification interface.
5. SIMULATION AND RESULTS The performance of SMIB has been studied (1) With excitation system (2) With conventional PSS (3) With fuzzy logic-based power system stabilizer The data taken from:
Fig. 6: design of fuzzy logic controller
Fig. 7: SMIB with AVR only
(1) With excitation system The model used in the Simulink is shown in the fig. In this paper the term K is constant. And the value of K calculated by using above parameters: K1 0.7635, K 2 0.8643, K3 0.3230, K4 1.4188
Fig. 8: system response with K5 negative ISBN-978-81-932091-2-7
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(2) With conventional power system stabilizer(CPSS)
(3) With fuzzy logic based power system stabilizer
Fig. 9: SMIB with AVR and PSS Fig. 11: Simulink model with fuzzy logic based PSS
Fig. 10: variation of angular speed, angular position and torque when PSS is applied with K5 negative and positive
Fig. 12: results of variations of angular speed and angular position when system with fuzzy logic-based PSS ISBN-978-81-932091-2-7
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6. Conclusions In this paper work is carried out to dampout the oscillation of the power system using fuzzy logic based controller on a single machine infinite bus system. FLPSS shows that superior performance than the power system stabilizer in term of settling time and damping effect. So, we can conclude that the performance of FLPSS is more better than conventional power system stabilizer. 1.
2.
3. 4.
5. 6.
7. REFERENCE K.Gowrishankar, M.D.Masud khan 2012. Matlab Simulink Model Of Fuzzy logic controller with PSS and its performance anlaysis Kamalesh Chandra Rout And Dr.P.C.Panda 2010. Dynamic Stability Enhancement of Power System Using Fuzzy Logic Based Power System Stabilizer D. K. Sambariya, R. Gupta and A.K. Sharma 2005. Fuzzy Application To Single Machine Power System Stabilizer Neeraj Gupta And Sanjay K. Jain 2010. Comparative Analysis of Fuzzy Power System Stabilizer Using Different Membership Functions Jenica Ileana Corcua And EleonorStoenescun 2007. Fuzzy Logic Controller as a Powers System Stabilizer Manish kushwaha and Mrs. Ranjeeta khare 2013. Dynamic Stability Enhancement of Power System using Fuzzy Logic Based Power System Stabilizer
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Impact of Facts Device on Protective Distance Relay Taral Falgunibahen R., Rashesh P. Mehta Electrical Engineering Department, BVM Vidtanagar Gujrat, India Corresponding Author: falgunitaral@gmail.com
Abstract This paper presents simulation of protective distance relay with and without FACTS (Flexible AC Transmission System) device such as STATCOM (Static synchronous compensator). FACTS Device are widely used to improve long transmission line capacity and increases reliability of system. But when STATCOM is connected in transmission line and fault is after STATCOM, it has a great impact on distance relay tripping characteristics. Simulation result is used to discuss the impact of distance relay for different mode of STATCOM located on Transmission line. We verify the proposed model under different types of fault and fault locations. The simulation is carried out in PSCAD software. Keywords – FACTS devices, Distance relay, MHO relay, Modelling PSCAD/EMTDC
1.
Introduction
In recent years due to industrialization and urbanization life styles, there is tremendous increase in electric power demand. This makes existing system very complex. So to meet this electrical power demand new transmission lines can be added or some devices can be installed on existing transmission line without affecting efficiency and reliability of the system. Installing new transmission line in power system can increase technological complexities, economic and environmental problems. So, adding new devices such as FACTS (Flexible AC Transmission System) have supported the transmission system and increase the capacity of transmission line. With the help of FACTS devices bus voltage, line impedance and phase angle in the power system can easily be manipulated and rapidly regulated to increase the stability of the system. But installing FACTS devices in transmission not only change the impendence but also change the voltage and current signals due to addition of decaying DC component, sub synchronous frequency components and odd-harmonics component. [1] Distance protection is mainly used to protect the transmission line. Its principle depends on electrical measures like voltage and currents. Distance relay measure the impedance between relay location and fault point by measuring the voltage and current ratio computation. This impedance is directly proportional to the length of transmission line. The relay will operate when ratio of voltage
and current i.e. impedance is less than the line impendence. But the presence of FACTS devices in fault loop affects both transient and steady state components of voltage and current at the relay point. This causes distance relay in overreach or under reach problem, which results in unwanted tripping signal given to the circuit breaker in the presence of FACTS devices in transmission line. [2, 3] Therefore, it is very important to study the impact of FACTS devices on traditional protective relay scheme such as distance relay for transmission line. This paper will analyse impact of STATCOM on distance relay when STATCOM is connected in transmission line. A model of distance relay with STATCOM proposed in PSCAD. The simulation results obtained after installing FACTS devices in transmission line clearly show the impact of FACTS devices on distance relay.
2.
FACTS Devices
The IEEE defines FACTS as “Alternating current transmission systems incorporating power electronics-based and other static controller to enhance controllability and increase power transfer capability”. FACTS Controller can be divided into four categories: Series controller: In principle, all series controller inject voltage in series with the line. Variable impedance multiplied by current flow through it, represents an injected series voltage in the line. This series controller could be variable ISBN-978-81-932091-2-7
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impedance, such as capacitor and inductor. This only supply or consumes variable reactive power. Shunt controller: They represent current source connected in shunt with the line. Shunt Controllers only generate or absorb reactive power due to the injected current in phase quadrature with line voltage. Combined series-series controller: This could be a combination of separate series controllers, which are controlled in a coordinated manner in a multiline transmission line. They control active as well as reactive power. Combined series-shunt controller: This could be a combination of separate shunt and series controller, which are controlled in a coordinated or Unified Power Flow Controller with series and shunt elements.it also control active and reactive power. [4] STATCOM is one of the key FACTS controllers. It can be based on a voltage source converter or current-source converter. The voltage soured converter is most preferable. The STATCOM converts the input voltage (Vdc) into three phase output voltages with desired amplitude, frequency and phase or the output voltage of the inverter must be in synchronous operation with the system voltage under any condition. STATCOM also designed to act as an active filter to reduce harmonics in the system. STATCOM installed in transmission line for many applications such as: Increasing the power transmission capability Improving the transient and steady state stability Damping of power oscillation also improving Power factor correcting Current harmonics eliminating HVDC-link performance improving Based upon the system application STATCOM is connected in the system. The voltage sag is largest at the midpoint of transmission line, so best location of STATCOM is midpoint of transmission line. For a radially fed loads, the best location for STATCOM is at load end. STATCOM absorbs or generate the reactive power and maintain
them within an acceptable level. In this paper 12-pulse IGBT type STATCOM is used. [4, 5]
3.
Distance Relay
Distance relay are used for protection of long and extra high voltage transmission line, transmitting power at 132 KV, 220 KV, and 400 KV. The settings of distance relay can easily be carried out and they provide back-up protection as compared to other relay like over current relay. The over current relay principally dependant on only magnitude of fault current. There are some parameters in transmission line such as source impedance, line resistance, fault location, type of fault etc. These parameters affect the measurement of current by the relay, which causes unsatisfactory performance of overcurrent relay. [8] Distance relay able to detect a fault in transmission line which depends upon the impedance of transmission line which is function of length transmission line. There will be a change in determined impedance because the fact that current will increase and voltage decrease when fault occurs. Therefore impedance will decrease according to ohm’s law and distance relay compare this value with pre-set value, if measured value is smaller than pre-set value then fault is detected and tripping signal is issued to circuit breaker to isolate the healthy portion from faulty portion. Distance relay does not provide protection of 100% line because the error in current and voltage transformer. [5] The highest error in impedance measurement is occurs under a faulty condition that is located anywhere from 85% to 100% of protected line. To solve this error in impedance measurement, the zone-1 is set about 85% of the section to be protected. The distance relay operates instantaneously if the fault occurs in zone-1. The zone-2 covers the first line section plus approximately 50% of the next line section. And operate with sufficient time delay while zone-3 of this relay encompasses the full second line section and provide the back-up protection for transmission line. [8] In this case the mho relay is taken and zone wise fault is creates and compare result.
4.
Simulation Scheme
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To explain and simulate the power system using two sources including STATCOM and DISTANCE RELAY at the sending end, the PSCAD/EMTC software used. PSCAD is graphical user interface, provide vary flexible interface to the electromagnetic transient simulation software. [12] Connect FACTS device such as STATCOM with transmission line and effect of STATCOM on protective distance relay is observed by MHO characteristics of distance relay. Table 1 simulation data System Voltage
500 kv, 3 Phase
Supply Frequency
60 Hz
X’mission length(TL1+TL2+TL3)
line
300 km
Positive Seq. Impendence
0.0127+j0.3520 Ω/km
Zero Seq. Impendence
0.3864+j1.5556 Ω/km
STATCOM Rating
± 100 Mvar
Simulation:
Table 2 Settings of Zones of Protection Zone R X Zone 1 Zone 2 Zone 3
5.
1.082Ω
29.902Ω
1.5276Ω
42.218Ω
2.8006Ω
77.39Ω
Simulation Results
Fig.1 shows a typical 300km, 500KV transmission line. The Power system simulation includes three main parts… (1) Compile all the parts of distance relay: The inputs of distance relay are voltage and current at relay location and the output are resistance and reactance of transmission line. Fault types are stored in PSCAD to use it later to draw the impedance trajectory and tripping signal. (2) Second 12 pulses STATCOM is design in PSCAD environment and it has many applications like regulating voltage by setting the desired reference voltage, fix reactive current and fix the reactive power. (3) Other power system components required are transmission line, three phase source, loads, and circuit breaker. dist_relay1 : XY Plot X Coordinate Ra Rb Rc
Y Coordinate Xa Xb Xc +y
100 50 0
-x
+x
-50 -100 -100
-50
-y 0
Aperture
Figure 1 500kv, 300km transmission line with STATCOM simulation
50
100 Width 0.5
0.000s
0.500s
Position 0.000
Figure 2 Fault at 50km without STATCOM
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dist_relay1 : XY Plot X Coordinate Ra Rb Rc
X Coordinate Ra Rb Rc
Y Coordinate Xa Xb Xc
150
150
100
100
50
50
0
-x
0
+y
200
+y
200
Y Coordinate Xa Xb Xc
+x
-x
+x
-50 -100
-50
-150
-100
-200
-150
-200
-200 -200
-y 0
-100
100
100
200
Width 0.5 0.000s
200
0.500s
Position 0.000
Figure 5 with STATCOM (inductive mode)
Width 0.5 0.500s
-y 0
Aperture
Aperture 0.000s
-100
Position 0.000
dist_relay1 : XY Plot
Figure 3 with STATCOM at 100km fault at 5okm
In this case line to ground (AG) fault taken at 50km and STATCOM is at 100km. The measured impedance is all most same with and without STATCOM. But if fault at 205km and STATCOM is in capacitive mode and its location is at 100km, fault occurs in zone 3 but impedance trajectory show the fault is out of zone.
X Coordinate Ra Rb Rc
Y Coordinate Xa Xb Xc
150
+y
100 50 -x
0
+x
-50
dist_relay1 : XY Plot
-100
X Coordinate Ra Rb Rc
Y Coordinate Xa Xb Xc
150
-150 -150
-100
-50
-y 0
Aperture
100
150
Width 0.5 0.000s
+y
50
0.500s
Position 0.000
Figure 6 Fault at 205km without STATCOM
100 50 -x
0
+x
-50 -100 -150 -150
-100
-50
-y 0
Aperture
50
100
150
Width 0.5 0.000s
0.500s
Position 0.000
Figure 4 Fault at 205km without STATCOM
From the above simulation result the following conclusions can be drawn: The STATCOM is located within the fault loop affects the distance relay performance. During a fault, the apparent impedance will decrease if the STATCOM consumes reactive power from the system and the apparent impedance will increase if the STATCOM supply the reactive power. Distance relay will over reach when the STATCOM consumes the reactive power and
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it will under reach when supply the reactive power. Position of distance relay will also affects the distance relay performance.
Figure 7 with STATCOM (capacitive mode)
6.
Conclusion
This paper presents the 500kv, 300km long transmission line simulation with STATCOM and having three zones. STATCOM is installed for reactive power compensation. Fault is created in different zones and zone wise results taken with and without STATCOM connected. STATCOM in its capacitive mode results in under reach and its inductive mode results in over reach problem. There will be adverse effect on distance relay when STATCOM is in fault loop.
7.
References
1. N.G.Hingorani and L.Gyugyi 2000. Understanding FACTS concept and technology of flexible AC transmission system IEEE press. 2. Gerhard Ziegler, 2006 Numerical distance protection principle and Application, 2nd Ed, berlin and menschen Siemens Aktiengesellschaft, Ed. Erlangen, Germany: publics corprate publishing.
3. M.P.Thakre, V.S.Kale, Jan 2014 .Distance protection for long transmission line using PSCAD, International Journal of Advance in Engineering & Technology (IJAET), Vol.6, Issue 6, pp.2579-2586. 4. M.P.Thakre, Dr. V.S.Kale, 2014. “Impact of STATCOM on distance relay", International Conference on Circuit, Power and Computing Technology (ICCPCT-2014). 5. Ahmed Albehadili, Ikhlas AbdulQudar 2015, Analysis of Distance relay performance on Shunt FACTS – Compensated Transmission Line (IEEE-2015). 6. Dannana Hemasundar, M.P.Thakre, Dr. V.S.Kale 2014. Impact of STATCOM on Distance relay- Modeling and simulation Using PSCAD/EMTDC, Conference on Electrical, Electronics and Computer Science (IEEE-2014). 7. Mojtaba khederzadeh, 2002. Impact of FACTS devices on Digital multifunctional protective relay, (IEEE-2002). 8. Power system protection and switchgear by Bhuvanesh A Oza, Nirmalkumar C Nair, Rashesh P Mehta, and Vijay H Makwana. 9. Krishna T. Madreware, Vivek. R. Aranke, Gorakshnath B. Abande,2015.Effect analysis of shunt device on distance protection in PSCAD and MATLAB for L-G Fault, International Conference on Energy and Application (ICESA 2015). 10. Hadi H. Alyami, 2015.protective relay model for electromagnetic transient simulation International Journal of Innovative Research in Advanced Engineering (IJIRAE) volume 2 Issue 1(January 2015) 11. Cesar Rincon, Entergy, Jackson MS, 39215 Joe Perez, P.E., ERLPhase Power Technologies, Bryan, TX77802 Calculating load ability limit of distance relay. 12. EMTDC/PSCAD Simulation Software, Ver.4.5
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Study and Review of Design and Simulation of CCM Boost Converter for Power Factor Correction Using Variable Duty Cycle Control Bharat S. Suthar, Swapnil Arya Department of Electrical Engineering, BVM Vallabh Vidyanagar,Anand, Gujarat,India Corresponding Author: sutharbharat06@gmail.com
ABSTRACT In an electrical Power system, a load with a poor power factor draws more current than high power factor for the same amount of useful power transferred. With the vast development in the usage of Power electronic devices like Rectifiers (non-linear loads) the current drawn from the line is distorted resulting in a High Total Harmonic Distortion (THD) and Low Power Factor (PF). Hence there is a continuous need for Power factor correction and reduction of line current harmonics. The most popular topology for Active PFC is a boost converter as it draws continuous input current. The aim of this work is to develop an active PFC control circuit using CCM boost converter implementing variable duty cycle control. It also regulates the output DC voltage. Keywords: Power Factor Correction, CCM Boost converter, Total Harmonic Distortion Variable duty cycle
Ι. INTRODUCTION Extensive use of power electronic devices has given rise to the need of making power management flexible, smart and efficient. Nonlinear current drawn by power electronic devices affects the power quality. Most of the electrical and electronic appliances such as laptops, desktops, UPS (Uninterruptible power supply), and VFD work on D.C supply. Designing D.C power supplies for such applications is very necessary. AC to DC converter or rectifier is a device that converts ac to dc and this conversion is done by switching devices such as diodes, thyristors, power MOSFET’s, etc. AC to DC converter consisting of diode with a large output filter capacitor is cheap and robust but very inefficient. Due to the non-linear behaviour of the switches they tend to draw highly distorted input current relative to the line voltage. As a result, input power factor becomes very low and also produces a harmonic that may interfere with other equipment. Low power factor results in poor output voltage regulation, therefore increased current and losses. Moreover, utilities will charge a higher cost to industrial and
commercial clients having a low power factor. Thus, overall efficiency of the system is degraded.
Fig 1 : Input current waveform of the nonlinear load with and without power factor correction circuit. To improve the power quality of the distribution system two types of power factor correction topologies are used, (1) Passive power factor correction topology and (2) Active power factor correction topology. Passive PFC techniques incorporating L and C components are the best choice for linear loads because Passive power factor correction ISBN-978-81-932091-2-7
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technique has a poor dynamic response and lack of voltage regulation. For nonlinear loads active PFC techniques are preferred due to their superior performance more than passive PFC techniques. Active PFC can be implemented by using any one of the following topology: Buck, Boost and Buck-Boost Topology. Buck and Buck-boost converters produces pulsed input current requiring additional filtering. The fundamental property of the boost converter is to produce a smooth input current waveform, therefore reduce filtering action is require and also increases efficiency of the system. By reducing the inductor-current ripple, the boost converter decreases current stress and increases the current handling capability at heavy loads for these reasons, the boost PFC circuit operating in continuous conduction mode (CCM) is the popular choice for medium- and high-power applications. The general goal of the boost PFC converter is to turn the switch (S ) off and on rapidly and with a varying duty cycle in order to make the input current (i ) sinusoidal and in phase with the input voltage (v ).
Π IMPLEMENTATION OF ACTIVE PFC CONTROLLER USING BOOST CONVERTER IN CCM MODE
Fig 2 : Boost PFC topology Block diagram of the boost converter PFC is as shown in above Figure 2. It consists of boost inductor, switch (MOSFET, IGBT etc.), fast recovery diode, capacitor and control circuit. It has a smooth input current because
an inductor is connected in series with the power source as shown in fig 2. The boost converter controls two functions : first- shape of the source current and second- magnitude of the output voltage. To accomplish this, there are two necessary conditions: first - the output voltage should be higher than the peak of the rectified input voltage, and second- the power flow should be unidirectional. Current path for different time instants can be considered as shown in the Figure 3 and Figure 4.
Fig 3 : Current path for the ON state of the switch
Fig 4 : Current path for the OFF state of the switch. The boost PFC circuit consists two states. The first state occurs when S is closed, as shown in Figure 3. When in this state, the inductor is being energized by the AC side of the circuit via the rectifier, and thus the inductor current will be increasing. At the same time, diode D becomes reverse biased (because its anode is connected to ground through S ), and energy is provided to the load by the capacitor. Figure 4 shows the second state, which occurs when S is open. In this state, the inductor de-energizes (the current decreases) as it supplies energy to the load and for recharging the capacitor. The boost PFC converter implements two control loops-a voltage loop and a current loop. The objective of voltage loop is to regulate the output voltage of boost converter ISBN-978-81-932091-2-7
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and the objective of current loop is to make the supply current to follow the sinusoidal waveform of the supply voltage, providing high power factor (PF) and low total harmonic distortion (THD). Current control loop implements average, peak or hysteresis current control.
Ш BOOST PFC CONVERTER WITH VARIABLE DUTY CYCLE CONTROL For simplicity, the following assumptions are made: 1) All the devices and components are ideal; 2) The ripple of the output voltage is too small to be neglected; and 3) The switching frequency is much higher than the line frequency. Source voltage VS , VS VP sin t …………………….(1) Where, VP is the peak value of the source voltage and is the angular frequency of the source voltage. The rectified voltage, Vd V p | sin t | ……………………..(2)
V p Dy2 1 iLavg (t ) iLpk (t )( Dy Dr ) 2 2 Lf s
sin t Vp 1 | sin t | Vo
……………………………..(6) Thus the supply current is, V p Dy2 sin t is (t ) V 2 Lf s 1 p | sin t | Vo ……………………………….(7) Fig. 5 shows that the envelope of the peak value of inductor current is sinusoidal. However, the envelope of the average value of inductor current is not sinusoidal and contains distortion it. For analysis purpose the average inductor current is normalized with the base of (Vm Dy2 2 Lf s )(1 Vm V0 ) , so (7) is rewritten as,
sin t V 1 P | sin t | Vo …………………………………(8) is (1
Vp
Vo
)
The inductor peak current is, V | sin t | V iLpk (t ) d DyTs p DyTs L L ……………………….(3) where, Dy is the duty cycle corresponding to the ON time of the switch; Ts is switching period. In a switching cycle, the inductor has a voltsecond balance, Vd DyTs (VO Vd ) Dr Ts …………………………………..(4) Dr is the duty cycle corresponding to the OFF time of the switch; VO is the output voltage of the boost converter Equation (4) can be written as, V p | sin t | Vd Dr Dy Dy VO Vd Vo V p | sin t | ……………………………..(5) From (3) and (5) average inductor current is,
Fig 5 : Inductor waveform in a half line cycle Assume 100% efficiency for the converter, i.e. Pin Po the duty cycle is, Dy
1 Vm
2 Lf s Po sin 2 t d t 0 Vp 1 | sin wt | Vo
………………………………….(9)
IV. VARIABLE DUTY CYCLE CONTROL TO IMPROVE THE INPUT POWER FACTOR In (9) is assumed to be constant. In order to achieve power factor nearer to unity is assumed to be variable as follows, ISBN-978-81-932091-2-7
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Vp
| sin t | Vo ………………………………..(10) Substitution of equ. (10) in to equ.(7) leads to V p D02 | sin t | is (t ) 2 Lf s ……………………………..(11) Assuming 100% efficiency for the converter the average input power is derived as, 1 V D2 V 2 D2 Pin Vm m 0 m 0 po 2 2 Lf s 4 Lf s …………………………………(12) P Lf Do 2 o s Vm ……………………………………….(13) Substitution of equ. (13) in to equ. (10) 2 Lf P 2 Lf P Vp Vp s o s o Dy 1 | sin t | 1 Vp Vo Vp Vo ……………………………………(14) The Duty cycle expressed in (14) is complicated It can be simplified as follows Assuming a Vm Vo ; y | sin t | , (10) can be rewritten as, Dy Do 1 ay Dy Do 1
VI. CONCLUSION This paper presents variable duty cycle control for CCM Boost PFC converter. CCM mode of boost converter is chosen which features smaller inductor current ripple resulting in low RMS currents on inductor and switch thus leading to low electromagnetic interference. Using this technique input current is made to follow supply voltage effectively. Thus the input power factor for diode bridge rectifier is improved and harmonic content in the input current is reduced. It also regulates the output DC-bus voltage
……………………………(15) Based on Taylor’s series, 1 1 f ( x) f ( x0 ) f ' ( xo ) f " ( x0 )( x x0 ) 2 ... f ( n ) ( x0 )( x xo ) n ... 2! n! Fig 6 : CCM Boost converter …………………(16) Equation (15) can be expressed as REFERENCES 1 3 a 1 a2 Dy Do [ 1 ay (1 ay0 )] 2 ( y yo ) (1 ayo(1) ) 2 (Sujata y yo )2Powniker,Student ...] Member, IEEE 2 2! 4 and Sachin Shelar, Member, IEEE ………………….(17) “Development of Active Power Factor Reserving only first derivative term, (17) is Correction Controller Using Boost approximated as Converter” IEEE International WIE 1 a a Conference on Electrical and Computer Dy _ fit Do [ 1 ay (1 ay0 )] 2 ( y yo )] D1 (1 y) Engineering December 2016, AISSMS, 2 2 ayo Pune, India …………………………..(18) (2) M. Nirmala “Design and Simulation of Where D1 ( D0 (2 ay0 )) (2 1 ay0 ) CCM Boost Converter for Power Factor Correction Using Variable Duty Cycle V. SIMULATION Control” International Journal of Fig. 6 shows the MATLAB simulations of Electrical, Computer, Energetic, CCM boost PFC converter with variable duty Electronic and Communication cycle control. Engineering Vol:8, No:1, 2014 ISBN-978-81-932091-2-7
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(3) P. Suresh kumar, S. Sridhar, T. Ravi kumar “ Design and Simulation of Boost Converter for Power Factor Correction and THD Reduction” 2014 IJSETR Vol.03,Issue.42 (4) Saubhik Maulik, Prof. Pradip Kumar Saha, Prof. Goutam Kumar Panda “ Power Factor Correction By Interleaved Boost Converter Using PI Controller” Int. Journal of Engineering Research and Applications www.ijera.com ISSN : 22489622, Vol. 3, Issue 5, Sep-Oct 2013 (5) Hiten Pahilwani “Power factor correction using boost converter” International Journal of Application or Innovation in Engineering & Management Volume 4, Issue 8, August 2015 (6) P.V.R.K.B.A.N.Raju ,I.Sudhakar babu, Dr. G.V.Siva Krishna Rao “ Simulation of Active Power Factor Correction Using Boost Type Converter” International Journal of Science, Engineering and Technology Research (IJSETR), Volume 3, Issue 10, October 2014
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Dynamic Voltage Restorer for Power Quality Improvement Jain Shilpa Pavan, Bhupendra R. Parekh Department of Electrical Engineering, BVM Vallabh Vidyanagar, Anand, Gujarat, India Corresponding Author: jainshilpa137@gmail.com
Abstract Power quality is one of the chief concerns in distribution system in commercial and modern industrial application. The problem of power quality is manifested as nonstandard voltage, current or frequency which may result to the failure of end user equipment. Transients sags, swells and harmonic distortion contribute to the critical problems in power quality out of which the sags and swells are predominantly found and have severe effect on sophisticated device whose performance is very sensitive the power supply quality. Custom Power Device is used to overcome this problem. DVR is one of the most efficient and modern custom power device used in power distribution system. It includes the advantage of lowest cost, smaller size and fast dynamic response to the disturbance. This paper presents the modelling, analysis and simulation of DVR using MATLAB/SIMULINK based on PI controller. The simulation results show the effectiveness of DVR for voltage sag mitigation and a better voltage profile. Keywords: Dynamic Voltage Restorer, Power Quality, voltage sag, voltage source inverter
I.
Introduction
Power quality is the delivery of sufficiently high grade electrical services to the customer.The modern industrial devices used nowadays are typically based on the electronic devices such as programmable logic controllers, variable speed drives and other precision electronic equipments, which are extremely susceptible to disturbances such as voltage sags, swells and harmonics .Amongst all the problem of voltage sag is considered to be one of the most severe problems to the industrial equipments.. Sag, as defined by IEEE standard 1159-1995, IEEE Recommended Practice for Monitoring Electric Power Quality, is a “decrease in RMS voltage or current between 0.1 p.u and 0.9 p.u, at the power frequency for durations from 0.5 cycles to 1 minute”. The problem of power quality may arise due to a variety of events ranging from switching actions at the customer ends or faults on transmission lines. Voltage sag can cause an unacceptable function and eventual shut down of industrial machines and equipments, resulting loss of production and operation. Voltage compensation can be achieved by installing A custom power device is used to suppress out the disturbances at the customer end to achieve voltage compensation. The DVR is considered as a
competent custom power device for mitigating the impact of voltage disturbances on sensitive load. It also has added features like low cost, fast dynamic response, and compensation of harmonic and reactive power.
II.
Dynamic Voltage Restorer
A DVR is the most efficient and effective modern custom power device used in power distribution networks. The DVR as shown in figure 1 is a series connected solid state device that injects additional voltage required by load into the supply system in order to adjust the load voltage to the desired amplitude and waveform even when the source voltage is unbalanced or distorted. This process involves insertion of real/reactive power from DVR to distribution feeder for voltage compensation. A DVR prevents voltage sag and provide voltage regulation. It can also work as a harmonic isolator to prevent the harmonics in the source voltage reaching the load. The heart of the DVR is Control unit, whose main function is to detect the presence of voltage sags in the system and calculate the required compensating voltage for the DVR so that appropriate reference voltage is generated for PWM generator and accordingly gate pulses triggered on the PWM inverter.
III.
Operating modes of DVR ISBN-978-81-932091-2-7
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A.
Protection mode: If the over current on the load side exceeds a permissible limit due to
Fig. 1 Block diagram of DVR short circuit on the load or large inrush current, the DVR will be isolated from the systems by using the bypass switches (S2 and S3 will open) and supplying another path for current (S1 will be closed).
B.
Fig. 2 Mode of operation C. Standby mode: Under the normal conditions the DVR may either go into short circuit or inject very little voltage for compensation of voltage drops on transformer reactance and losses. D. Injection/boost mode: As soon as the sag is detected DVR goes into boost operating mode. For compensation, AC voltage is injected in series to the feeder with required magnitude and phase.
IV.
Power circuit
A. Injection/Booster transformer: The basic purpose of injection transformer is to connect the DVR to the distribution feeder through the HV-windings and adds DVR voltage which is generated by Voltage Source
Inverter (VSI) to the incoming supply voltage after the detection of any sag by the control unit. This transformer increases the DVR voltage to the desired level. B. DC-link and Energy Storage Devices: The DC-link and energy storage device provides the real power requirement of DVR during compensation period. Flywheels, batteries, superconducting magnetic energy storage (SMES) and super capacitors can be used as an energy storage device. C. Voltage Source Inverter (VSI): VSI is a power electronics system consists of à dc link/energy storage device, and it can produce a sinusoidal voltage. The function of the VSI is to convert the dc voltage supplied by the energy storage device/dc-link into an ac voltage. D. Harmonic filter: The main task of the filter is to keep the harmonics voltage content generated by the VSI to the permissible level. By locating the filter at the inverter side the higher order harmonics are prevented from penetrating into transformer, thereby it decrease the voltage stress on the injection transformer. But there can be a phase shift and voltage drop in the inverter output, which can upset the control algorithm. By locating the filter at the load side phase shift cannot be occur but harmonics can penetrate into the high voltage side of the transformer, a higher rating transformer is required. E. By-pass Switch: The DVR is a series connected device and one of the drawbacks with series connected device is the difficulties to protect the device during short circuits and avoid interference with the existing protection equipment. During faults, overload or at time of maintenance a bypass path for the load current has to be ensured.
V.
Control circuit
The aim of the control circuit is to keep constant voltage magnitude at the point where a sensitive load is connected, under voltage disturbance. The control system measures the rms voltage at the load point. No reactive power measurement is required. The VSI switching strategy is based on SPWM technique which offers simplicity and good ISBN-978-81-932091-2-7
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response. The PI controller method identifies the error signal and generates the required angle δ to drive the error to zero, i.e., the load rms voltage is brought back to the reference voltage V ref. In the PWM technique, the sinusoidal signal Vcontrol is compared against a triangular signal (carrier) in order to generate the switching pulses for the VSI switches. The block diagram of control is shown in figure 3.
Figure 4 shows the test system used to carry out the DVR simulations is presented in this section. The DVR coupling transformer is connected in delta in the VSI side. The DVR system is composed by a 13 kV, 50 Hz supply system, feeding two transmission lines through a 3-winding transformer connected in Yg/Δ/Δ: 13KV/115KV/115 kV. Such transmission lines feed two distribution systems through two transformer of 115KV/11 KV. This test system is analyzed under three phase short
Fig. 3 Block diagram of control system
VI.
Simulation and results
The following table shows the specifications used for the simulation of DVR model. DVR parameters Values Main supply 13 KV voltage Series Transformer 1:1 Turn ratio DC bus voltage 5KV Active Power 1000W Load Reactive power 500W Line resistance 0.001Ω Line inductance 0.005 H Source resistance 0.1Ω Fault resistance 0.66Ω Switching 1080 Hz frequency Line frequency 50 Hz Table. 1 System parameters and control values The performance of DVR with these designed parameters is evaluated by performing it’s simulation in MATLAB/SIMULINK.
circuit fault. Fig. 4 MATLAB/Simulink Model of DVR The first simulation contains no DVR and a three-phase short-circuit fault is applied at point before injection transformer, via a fault resistance of 0.66 Ω, during the period 0.4 to 0.6 sec. The R.M.S voltage at the load point is 0.32 p.u as shown in Figure 5.
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be very robust in that case. The DVR has been modeled and simulated in MATLAB/SIMULINK. The simulations carried out here showed that the DVR provides relatively better voltage regulation capabilities and successful mitigation of voltage sag
REFERENCES 1.
Figure. 5 Load voltage without DVR The second simulation is carried out using the same scenario as above, but now DVR is connected to the system, then the voltage sag is mitigated almost completely, and the rms voltage at the sensitive load point is maintained at 0.8 p.u.as shown in Figure 6.
2.
3.
4.
5. Figure. 6 Load voltage with DVR
VII. Conclusion The performance of DVR has been analyzed for linear load. The Voltage Source Inverter (VSI) was implemented with the help of Sinusoidal Pulse Width Modulation (SPWM). The control scheme was tested under three phase fault conditions, and it was observed to
6.
Rakeshwri Pal, Dr. Sushma Gupta,2 December 2016. Simulation of Dynamic Voltage Restorer (DVR) to mitigate voltage sag during three-phase fault. International conference on electrical power and energy systems (ICEPES), pp. 14-16. Priyanka Kumari, Vijay Kumar Garg, JulAug 2013. Simulation of Dynamic Voltage Restorer using Matlab to enhance power quality in distribution system. International Journal of Engineering Research and Applications (IJERA), Vol.3, Issue 4, pp. 1436-1441. . S.Ezhilarasan, G.Balasubramanian,2013. Dynamic Voltage Restorer For Voltage Sag Mitigation Using Pi With Fuzzy Logic Controller. International Journal of Engineering Research and Applications (IJERA) Vol. 3, Issue 1, pp. 1090-1095. Deepa Francis, Tomson Thomas,2014. Mitigation of voltage sag and swell using Dynamic Voltage Restorer. In: International Conference on Magnetics, Machines & Drives (AICERA-2014 Icmmd). Sanjay Haribhai Chaudhary, Gaurav Gangil, May-Jun-2014. Analysis, modeling and simulation of Dynamic Voltage Restorer (DVR) for compensation of voltage for sag-swell disturbances. IOSR Journal of Electrical and Electronics Engineering (IOSR JEEE), Vol. 9, Issue 3, pp. 36-41. Math H.J. Bollen. Understanding Power Quality Problems Voltage sags and interruptions. IEEE press.
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Design of Active Shunt Filter for Harmonics Reduction at Load Side for Power Quality Improvement Makawana Mukundkumar M., Swapnil Arya Department of Electrical Engineering, BVM Vallabh Vidyanagar, Anand, Gujarat, India Corresponding Author: makwanamukund424@gmail.com
ABSTRACT In the recent years the excessive use of power electronic devices and other non-linear loads in industries have evolved the problem of power quality deteriorating the power system voltage and current waveforms by injecting harmonics in the utility supply source. Active harmonic filter helps to overcome this problem and enhance the power quality. This paper represents the effective solution of power quality problem by utilizing the shunt active power filter for eliminating the harmonics with the help of Instantaneous real and reactive power (p-q) theory for generating reference current. The hysteresis controller is used to get required compensation current to be injected at point of common coupling (PCC). The simulation is carried out in MATLAB/SIMULINK for the Instantaneous real and reactive power (pq) theory and the results prove the effectiveness of Shunt active power filter for reduction of harmonics (THD) up to permissible limit and reactive power compensation to maintain power supply quality. Key words – Power quality, Active shunt filter, Instantaneous reactive power theory, Hysteresis current control.
I.
INTRODUCTION
The power quality improvement is a major task nowadays. About 20 years ago, mostly passive and linear load were used. The usage of nonlinear load was comparatively much lesser thus it was having negligible impact on power quality issues. Because of easier controllability of power electronics and semiconductor device, nonlinear loads like rectifier, choppers and SMPS etc. are used in every system. The power electronic devices are very suitable for domestic use. Due to the use of the power device, the reactive power disturbances and harmonics becomes notable in the power network. The harmonics and reactive power leads to various problems like distortion of feeder voltage, overheating of transformers and electric motors, low power factor, excessive neutral current, interference with communication systems. The growing concern of good power quality and awareness with the harms to power system due to harmonics along with the penalties imposed by utility companies and the standards to the limit of THD made by International standards concerning electrical power quality (IEEE- 519, IEC 61000, EN 50160, among
others) impose that electrical equipment and facilities should not produce harmonic contents greater than specified values, and also specify distortion limits to the supply voltage. And also make it mandatory to solve the harmonic problems caused by that equipment already installed. The purpose of the filter is to reduce the harmonics from the system and also providing the reactive power into the system and improve the power factor. [2] The classification of harmonic filter is given in Fig. 1.
Harmonic Filter Passive Filter
Active Filter
Hybrid Filter
Fig. 1 Classification of harmonic filter
II.SHUNT ACTIVE POWER FILTER Most of the connection of the active filter is done in shunt manner, which means that it will behave as the voltage source and injects the current into the system. ISBN-978-81-932091-2-7
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Fig. 1 shows the basic compensation principle of shunt active power filter. A voltage source inverter (VSI) is used as the shunt active power filter. ASPF injects a compensating current IF to the utility, such that it cancels current harmonics on the AC side i.e. this shunt active power filter (SAPF) generates the nonlinearities opposite to the load nonlinearities. Active shunt Filter is convenient Solutions for Power Quality Problems such as Current Harmonic Filtering, Reactive power compensation, Current unbalance, Voltage Flicker.
Fig. 2 Basic diagrams of ASPF A. INSTANTANEOUS PQ THEORY In this paper simulation carried out for SAPFs uses p-q theory. The p-q theory is one of several methods that can be used to generate reference current for active filters. The p-q theory is a very efficient and flexible for designing of control strategies and implementation. [5] So that this power theory has been largely used in the implementation of SAPFs over the years, and has provided good results with different types of electrical installations and loads. [7] For p-q theory the electrical grid voltages (Va, Vb, Vc) and the load currents (ia, Ib, ic) must be converted to α-β reference frame by applying the Clarke transformation, given by (1) and (2): 1 1 Va V 2 2 2 1 . Vb -----(1) V 3 0 3 3 2 2 Vc
1 1 ia i 2 2 2 1 . ib ----- (2) i 0 3 3 3 2 2 ic The p-q theory power components are calculated using the expressions (3), where p is the instantaneous real power, and q is the instantaneous imaginary power. p V V I q V V . I ----- (3) Each one of the instantaneous power components can be separated into an average value and an oscillating value. The physical meaning of each of the instantaneous powers is: P - Average value of the instantaneous real power p. P῀- Oscillating value of the instantaneous real power. q - The instantaneous imaginary power. The α-β current calculation is done as shown in equation (4). Then the inverse Clarke transformation is carried out to find out reference compensation currents in a-b-c coordinated as shown in equation (5) ic V V P Ploss 1 2 -----(4) 2 ic V V V V q ica icb icc
1 2 1 2 3 1 2
3 ic 2 ic 3 2 0
-----(5)
B. HYSTERESIS CONTROLLER Hysteresis current control method can be used to get required compensation current to be injected at point of common coupling (PCC). There are many current control methods, hysteresis current control method is easily employed and give quick control of current. The advantages of hysteresis method are its Robustness and with minimum hardware it has fastest control. Disadvantages of hysteresis method are variable switching frequency. Whenever the current error fed to it exceeds the fixed band then the switching operation starts. For better accuracy the band should be smaller. The switch presents inside the ISBN-978-81-932091-2-7
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upper inverter arm becomes turned off if limit of current is over reached and that of the switch inside the lower arm gets turned on if the current limit is below limit. Now there is a decrease in current. The working principle is shown below. [3]
Fig. 3 Hysteresis Controller C. PI CONTROLLER The PI Controller is used to regulate constant DC voltage across the capacitor side of VSI. The DC voltage remains constant, until the active power absorbed by the converter decreases to level where it unable to compensate its losses. Fig. 4 shows PI Controller. The value of Kp and Ki are tuned by Zicholar Nichols method such that it generates regulated voltage. Vdc_ref
P_loss Ʃ
PI Controller
Vdc
Fig. 4 PI Controller D. PARAMETERS OF SAPF There are two main parameters plays a vital role in active shunt harmonic filter operation, 1. Interfacing inductor 2. DC link capacitor 1. Interfacing inductor The range of the coupling-inductance of an APF is expressed as eq. (6). [9] Vdc _ bus vVdc _ bus L -----(6) 8 f s ( Level 1)I r r I c
When the final value of the inductor is determined, it is suggested to select a value close to the lower boundary. The value close to the lower boundary could provide better current tracking speed with acceptable current ripples. The cost of inductor depends on its size. A smaller inductor reduces the cost. However, it is suggested to still test the final value by estimating the upper boundary according to (4). Sometimes, the upper limit obtained of the inductor is smaller than the lower limit. It indicates conflicts exist in the requirement of current tracking speed and suppressing current ripple. Some approaches, such as increasing PWM frequency and adopting multi-level VSI, could be considered to reduce the lower boundary. 2. DC link capacitor DC side capacitor of voltage source inverter serves two main purposes [5]: I.It maintains the DC voltage with small ripples in steady state. II.It serves as an energy storage element to supply a real power difference between load and source during the transient period. The power for charging the capacitor is drawn from the source via antiparallel diode used in bridge section. [2] The voltage of capacitor is to maintain to its reference value which is given by following equation. 2 VLL Vdc 2 -----(7) 3 m The size determination of the DC-bus capacitor is based on the energy balance principle. The amount of energy is storing in Capacitor is supplied from the source. The capacitor’s capacitance can be found out from the energy storage equation (8). 1 2 2 C DC (VDCref VDC ) 3V ph aIt -----(8) 2
III. SIMULATION MODEL AND RESULTS A.
Simulation Parameters Table 1 Simulation Parameters Supply Voltage
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B.
Supply Frequency
50Hz
Non-linear Load
100 Ohm.
Coupling Inductor
0.001 H
Dc capacitance
10e-6 F
Simulation Model
shown in fig (7). In this waveform the ASPF is not connected up to 0.1 second. So during this period the effect of harmonics are clearly seen. But after 0.1 second the ASPF is entered in to the circuit and it makes the waveform very much sinusoidal. During 0.1 to 0.2 seconds only nonlinear load is connected and after that from 0.2 to 0.3 seconds both linear as well as non-linear loads are connected to the three phase power supply.
Fig. 5 MATLAB simulation diagram of ASPF for p-q Theory Fig. 7 supply side V and I waveform
Fig. 6 sub circuit for Shunt active power filter C. Results The simulation is carried out using above parameters and the results are obtained as per
Fig.8 Load side V and I waveform
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Fig. 9 Compensated currents through ASPF for phase a
IV.
CONCLUSION
The VSI based shunt active power filter is simulated in MATLAB/Simulink using the Instantaneous real and reactive power (p-q) theory. The FFT analysis proves the effectiveness of shunt active power filter. Without SAPF the THD in current waveform is 28.98% and after connecting ASPF the THD is reduced up to 2.27%.
REFERENCES 1.
2.
3.
4.
Hirofumi Akagi, Edson Hirokazu watanabe, Mauricio Aredes. Instantaneous power Theory and Application to Power Conditioning,A John Wiley & Sons, INC., Publication. Dhaval P. Patel, Prof. Swati N. Purohit, Khoda N. Odedra, Ankit B. Patel,2017.Performance of Shunt Active Power Filter Controlled by Constant Power Control Technique.In: 3rd International Conference on Advances in Electrical, Electronics, Information, Communication and Bio-Informatics (AEEICB17), IEEE. Md Javed,Abinash Agrawal, 2015.Simulation and Experiments On One Phase and Three Phase Shunt Active Power Filters. PublishedB.Tech. thesis,Department of Electrical Engineering, National Institute of Technology, Rourkela. Wajahat Ullah Khan Tareen, Member, IEEE, and Saad Mekhielf, Senior Member, IEEE, 2017.Three-Phase Transformerless Shunt
Active Power Filter with Reduced Switch Count for Harmonic Compensation in Grid-
Connected Applications. IEEE Transactions on Power Electronics. 5. S. Parthasarathy, S. Rahini, S.A. Karthick kuma, 2015.Performance Evaluation of Shunt Active Harmonic Filter Under Different Control Techniques, International Conference on Circuit, Power and Computing Technologies [ICCPCT] 6. S. Shamshul Haq, D. Lenine and S.V.N.L. Lalitha,2015. Performance Analysis of Shunt and Hybrid Active Power Filter Using Different Control Strategies for Power Quality Improvement, springer Proceedings of ICECIT. 7. J. G. Pintol, Bruno Expostol, Vi tor Monteirol, L. F. C. Monteiro, Carlos Coutol, Joao L. Afonsol,2012.Comparison of Current-Source and Voltage-Source Shunt Active Power Filters for Harmonic Compensation and Reactive Power Control. In:IECON - 38th Annual Conference on IEEE Industrial Electronics Society, pp 5161 – 5166. 8. Balaga UdayaSri, P.A.Mohan Rao, Dasumanta Kumar Mohanta, M. Pradeep Chandra Varma,2016.Improvement of power quality using PQ-theoryshunt-active power filter.International conference on Signal Processing, Communication, Power and Embedded System (SCOPES). 9. Ning-Yi Dai, Man-Chung Wong,2011.Design Considerations of Coupling Inductance forActive Power Filters.In: 6th IEEE Conference on Industrial Electronics and Applications. 10. Hirofumi Akagi, Akira Nabae. Control Strategy of Active Power Filters Using Multiple Voltage-Source PWM Converters, IEEE. 11. J. G. Pintol, Bruno Exposto, Vi tor Monteiro, L. F. C. Monteiro, Carlos Coutol, Joao L. Afonsol, 2012.Comparison of Current-Source and Voltage-Source Shunt Active Power Filters for Harmonic Compensation and Reactive Power Control, IEEE. ISBN-978-81-932091-2-7
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A Study on Speed Control of BLDC Motor Using Fuzzy Logic Kerulkumar R Chaudhari, Akshay A. Pandya Department of. Electrical Engineering, BVM Engg College, Vallabh Vidhyanagar, Gujarat Corresponding Author: kerulchaudhari11@gmail.com ABSTRACT Due to the properties like high efficiency, reliability, high starting torque, less electrical noise and high weight to torque, Brushless DC Motor (BLDCM) has been used widely in industries. Importance of the speed controls of BLDCM is highly required because it indirectly controls efficiency by the mechanical output required. Controllers such as PWM, PI, Fuzzy and Neural Networks (NN) are used to control the parameter related to speed. This paper work deals with FLC design by using a simple analogy within the control surfaces of the FLC and a PI controller for the same. MATLAB / SIMULINK package program has been used for the simulation and analysis of model. Also, various study shows that the FLC offers better adaptability than conventional PI controller and due to this the BLDCM drive offers better steady state and dynamic performances. Keywords: BLDC Motor, Speed Control, PI Controller, FLC structure and ease of implementation; PI I. INTRODUCTION controllers are widely used in the industrial sector. These controllers at the same time pose Nowadays the use of BLDC motor instead of some difficulties such as control complexity brushed DC motor has increased in number of nonlinearity, load disturbances and parametric power electric drive applications. BLDC motor variations. comprise of sinusoidal (PMSM) or trapezoidal The use of faster dynamic response controller in (PM BLDC) motor, depending u1pon the motion control like Artificial Intelligence (AI), rotational voltage (back EMF) induced. Due to Adaptive Neuro Fuzzy Inference Systems the fact of recent advancements in technology, (ANFIS); is the substitution of a standard (PI) these motors which are categorized as special controller. FLC speed controller is one the electrical motors are much more suitable for frequently accessed controller used for the speed efficient drive operation. These motors are control of an electric drive. Fuzzy logic speed characterized by a much higher efficiency, control can sometime be seen as the ultimate greater reliability, and more power density solution for high-performance electrical drives. requiring less maintenance. Due to the fact that PI controller when compared with these recent PM BLDC has higher torque delivered to motor emerging controllers, found to be comparatively size ratio, high efficiency and long life; these inefficient. The reason for low efficiency in the motors find their application in various electrical PI controller is the high overshoot from the systems depending upon the requirements. In reference point, which leads to transients and this context it can also be noticed that from last large delay time to get into steady state. The slow few years, research in this area have experienced response on the sudden change of load torque an expansion. and the sensitivity to controller gains (Kp and The desired level of performance from BLDC Kc) are the other reasons for the obsoleteness of motor could be achieved by the use of suitable PI controllers. This has resulted in the increased speed controllers in the overall electric drivedemand of modern nonlinear control structures system. Many controllers like PI, FLC and NN like Fuzzy logic controller. These controllers are are available for the speed control of such inherently robust to load disturbances. BLDC electric drives. The Proportional plus Integral motors being non-linear in nature can easily be (PI) controller; is the most commonly used affected by the parameter variations and load standard controller applicable for speed control disturbances. of electrical drives. Due to the simple control ISBN-978-81-932091-2-7
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II. CONSTRUCTION AND PRINCIPLE OF OPERATION Brushless motor is considered to be an electronically commutated motor. It requires electrical switches for realizing commutation of current and hence motor is rotated continuously. These switches are connected in H-bridge structure. Figure 1 shows BLDC connected to driver circuit.
Figure 1: BLDC motor with driver circuit Three hall sensors are required for a three phase BLDC motor which is used to detect the position of rotor. Three sensors are placed on stator at 120-degree intervals. These windings are placed in a star formation. Each hall sensors changes its state for every 60-degree rotation and completes the whole cycle by taking six steps. Rotor pole pairs are used to determine number of cycles required to complete a mechanical rotation. Hence, number of cycles is same as rotor pole pairs.
III. BLDC CONTROLLERS
SPEED
There are several controllers available nowadays like proportional integral (PI), proportional integral derivative (PID) Fuzzy Logic Controller (FLC) or the combination between them: FuzzyNeural Networks, Fuzzy Genetic Algorithm, Fuzzy-Ants Colony, Fuzzy-Swarm. But as within the scope of this paper the discussion on
the PI and Fuzzy Logic Controller will be discussed as below. A.
PI Speed Controller A Proportional Integral (PI) is a feedback control loop mechanism used in electrical control system. PI Controller finds its applications in many industrial processes where a controller attempts to correct the error between a measured process variable and reference set point. The algorithm involves a calculation and outputting of a corrective action which is done in order to adjust the process accordingly. The PI controller, as the name indicates, involves two separate modes that are: the proportional mode and integral mode. The proportional mode determines the reaction to the current error whereas the integral mode determines the reaction based recent error. Due to its simple structure and ease of use; PI controller is widely used in industry. The speed of the motor is compared with its reference value and the speed error is processed in proportional integral (PI) speed controller. B.
Fuzzy Logic based Speed Controller Non-Linear Systems can be very easily modeled by Fuzzy Logic Controller (FLC). The conventional control system design is usually based on the mathematical model of plant which is generally complex mathematical equations. On the other hand, FLC expresses operational laws in terms of linguistics terms instead of mathematical equations. Sometimes it has been experienced that there are many systems which are too complex to model accurately, even with complex mathematical equations; therefore, conventional methods become infeasible in these systems. Henceforth, fuzzy logics linguistic terms provide a feasible and easy method for defining the operational characteristics of such system to design and implement. The generalized block diagram of a BLDC Motor with a controller as shown in Fig. 2, can be replaced by any other controller as required. ISBN-978-81-932091-2-7
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Any control mechanism can be adopted in the system such as PI, PID or Fuzzy Logic Controller which will be suitable to maintain and control the speed of the BLDC Motor.
Inputs are error (e) and change in error (ce). Difference of reference speed (ωref) and the original speed (ω) gives the speed error. Output voltage is the controller output. Membership function chosen is the triangular shaped function because of its simplicity and good controlling operation. Error, change in error and output voltage is the membership function used here. Seven level of membership function are applied for all the variables.
IV. Figure 2: Block Diagram of a BLDC Motor with Controller Scheme The section ahead explains the Simulink model of a BLDC Motor with a PI and a Fuzzy Logic Controller along with the simulations results which is discussed. FLC is an algorithm which is dependent on lingual strategy of control. It acquires human thinking about controlling the systems without mathematical modeling. Fuzzy logic’s lingual terminology is often exhibited using some of the logical insinuation like IfThen rules. These logical rules describe a scale of values which is known as fuzzy membership function. Block diagram of fuzzy logic controller is given below,
Figure 3: Fuzzy controller block diagram There are two types of fuzzy logic controller. They are Sugeno Takagi architecture and Mamdani architecture. For controlling speed, Mamdani architecture of fuzzy logic is used.
SIMULATION
Simulink model of a Permanent magnet BLDC Motor with the FLC is designed in a MATLAB Simulink tool. The Simulink model consists of a 3phase supply via inverter and a BLDC motor. The model is coupled with a FLC for the speed control of the motor. The model has been designed using the following parameters as shown in Table I. Table 1: PARAMETERS CHART Speed (N in RPM)
1500
Voltage (Vin volts) Poles of the Motor (P)
160
Motor phases (ф) Stator Phase Resistance (Rs in ohm)
3 0.7
Torque Constant (k)
0.84
Load Torque Back EMF area (degree) Rotor Initial Position (Ө in degrees ) Kp=Proportional Constant
2 N-m
Ki=Integral Constant
5
4
120 0 0.002
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order to keep the current within a certain range for a specific speed, could be a work for future. The proposed future work would thereby enhance the motor start-up current, reduce the motor current ripples and overall enhance the motor torque characteristics performance. Current control methodology will also reduce the speed and torque variations caused due to any sudden changes in the motor current value.
REFERENCE 1. 2. 3. 4. Figure 4: Simulation Model of the Speed Control of BLDC using FLC Fig. 4 shows the PM BLDC Simulink model with a FLC and the simulation results for the same have been shown ahead. The simulations results comprise of speed, torque and current characteristic curve of a BLDC motor with FLC.
V.
CONCLUSIONS
The speed control of a Permanent Magnet BLDC Motor is studied in this paper, using both PI controller, and Fuzzy Logic Controller. The paper explains about the performance analysis of a BLDC Motor in brief Further a comparative study has been discussed between the PI controller and Fuzzy Logic controller used on the MATLAB Simulink tool for the speed control of a BLDC motor. The inference which can be concluded after comparison is that speed control of BLDC using Fuzzy Logic Controller has better performance. To add current control function to the proposed speed controller in
5. 6.
7.
Tan Chee Siong, Baharuddin Ismail 2010. Study of fuzzy and pi controller for permanent-magnet brushless dc motor drive Adil Usman and Bharat Singh Rajpurohit 2016. Speed Control of a BLDC Motor using Fuzzy Logic Controller Shruti 2016. Speed Control of BLDC using Fuzzy Logic W. Hong, W. Lee and B. K. Lee 2007. Dynamic Simulation of Brushless DC Motor Drives Considering Phase Commutation for Automotive Applications S. Rambabu 2007. Modeling and control of a brushless DC motor M.Harith, K. P. Remya, Kalady ASIET, and S. Gomathy 2015. Speed Control of Brush less DC Motor Using Fuzzy Based Controllers Muhammad Firdaus Zainal Abidin, Dahaman Ishak, and Anwar Hasni Abu Hassan 2011. International Conference on Computer Applications and Industrial Electronics
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Hybrid Energy Management System design with Renewable Energy Sources (Fuel Cells, PV Cells and Wind Energy): A Review Seema Agrawal, Seemant Chourasiya, D.K. Palwalia Corresponding Author: Seema10dec@gmail.com Abstract This paper presents a novel adaptive scheme for energy management in stand-alone hybrid power systems. The proposed management system is designed to manage the power flow between the hybrid power system and energy storage elements in order to satisfy the load requirements based on artificial neural network (ANN) and fuzzy logic controllers. The neural network controller is employed to achieve the maximum power point (MPP) for different types of photovoltaic (PV) panels, based on Levenberg Marquardt learning algorithm. The statistical analysis of the results indicates that the R2 value for the testing set was 0.99.The advance fuzzy logic controller is developed to distribute the power among the hybrid system and to manage the charge and discharge current flow for performance optimization. The developed management system performance was assessed using a hybrid system comprises PV panels, wind turbine, battery storage, and proton exchange membrane fuel cell (PEMFC). To improve the generating performance of the PEMFC and prolong its life, stack temperature is controlled by a fuzzy logic controller. Moreover, perturb and observe (P&O) algorithm with two different controller techniques the linear PI and the nonlinear passivity based controller (PBC) are provided for a comparison with the proposed MPPT controller system. The comparison revealed the robustness of the proposed PV control system for solar irradiance and load resistance changes. Real time measured parameters and practical load profiles are used as inputs for the developed management system. The proposed model and its control strategy offer a proper tool for optimizing the hybrid power system performance, such as the one used in smart house applications. The research work also led to a new approach in monitoring PV power stations. The monitoring system enables system degradation early detection by calculating the residual difference between the model predicted and the actual measured power parameters. Measurements were taken over 21 monthâ&#x20AC;&#x2122;s periods; using hourly average irradiance and cell temperature. Good agreement was achieved between the theoretical simulation and the real time measurement taken the online grid connected solar power plant. I. INTRODUCTION Therefore, a solar-wind hybrid power system model will be presented [1-3]. The system will consist of a) PV panels, to convert the sunlight into direct current, b) wind turbine, to convert the kinetic energy from the wind into mechanical energy, c) DC generator, to convert the mechanical energy from the turbine into electrical energy, d) MPPT, to operate the PV at the maximum power point (MPP), e) fuel cells, which performs as a backup power source,
f) battery bank, to supply energy to the system when is needed and store it when is not needed, g) DC/DC converters, to steps-up the voltage to a higher DC voltage, h) DC/AC inverters, to generate AC waveform from the DC signal, (i) main controller, to ensure the continuous power supply for the load demand. A schematic diagram of a basic hybrid system is shown in Figure 1. II. Hybrid Power System: Modeling & Simulation In power applications and system design, modeling and simulation are essential to optimize control and enhance system operations. ISBN-978-81-932091-2-7
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The dynamic simulation model is described for a hybrid power system comprises PV panels, wind turbine, fuel cells, battery bank, converters and controllers.
Fig.1- Block diagram of a hybrid power generation system The main controller will have developed to ensure the continuous power supply for the load demand [4-5]. The following subsections present the implementation of the PV/wind turbine/ PEMFC/Li-Ion battery system model [6]. Modeling and simulation are implemented using MATLAB/ Simulink and Sim Power System software packages. The block diagram of the developed hybrid power system is shown in Figure 2.
A. The photovoltaic model A model of PV panel with moderate complexity which includes the series resistance, the saturation current of the diode, and the temperature independence of the photocurrent source is considered based on the Shockley diode equation. The PV model is built and implemented using Simulink to verify the nonlinear Iâ&#x20AC;&#x201C;V and Pâ&#x20AC;&#x201C;V output characteristics [7]. Each function uses a notation with a meaningful lettering to make it readable and maintainable; e.g. reverse saturation current function stands for the implementation of Equation (1). đ??ź = (1) Where IoÎą is the cellâ&#x20AC;&#x2122;s reverse saturation current at a solar radiation and reference temperature; voc is the cells open circuit voltage. The cell ideal factor (F) is dependent on the cell technology. The inputs for the proposed PV model are solar irradiation, cell temperature and PV manufacturing data sheet information. In this chapter, ADT 12AS PV module is taken as an example. The proposed PV model was simulated using MATLAB/Simulink, [8] as shown in Figure 3.
Fig.3 - Implementation of the PV model
Fig. 2 - Block diagram of the developed hybrid power system
B. The wind turbine model The amount of power that a wind turbine can extract from the wind depends on the turbine ISBN-978-81-932091-2-7
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design. Factors such as the wind speed and the rotor diameter affect the amount of power that a turbine can extract from the wind. The wind turbine was modelled using the mathematical equations [2]. đ?&#x2018;&#x192; = đ?&#x153;&#x152;đ??´ đ?&#x2018;&#x2030; (2) Where Ď is the air density in (kg/m3), AS is the swept area of blades (m²), v is the wind speed (m/s). As illustrated, there are three inputs and one output. The three inputs are the generator speed, the pitch angle, and the wind speed. The output is the torque applied to the generator shaft. The built-in Sim Power System block model of a DC machine is used as a power generator driven by the wind turbine (Math Works 2012). As shown in Figure 6, the rotor shaft is driven by the wind turbine which produces the mechanical torque according to the generator and wind speed values [10].
Fig. 6 â&#x20AC;&#x201C; Implementation of the wind turbine DC generator model A Proportional Integral (PI) controller is used to control the blade pitch angle in order to limit the electric output power to the nominal mechanical power [11]. C. The Li-Ion battery model The model of the Li-Ion battery is implemented in MATLAB/Simulink based on the mathematical
đ?&#x2018;&#x201E; đ?&#x2018;&#x201E; đ?&#x2018;&#x2013;đ?&#x2018;Ą â&#x2C6;&#x2019; đ?&#x2018;&#x2026; â&#x2C6;&#x2019; đ??ž đ?&#x2018;&#x2013;â&#x2C6;&#x2014; đ?&#x2018;&#x201E; â&#x2C6;&#x2019; đ?&#x2018;&#x2013;đ?&#x2018;Ą đ?&#x2018;&#x2013;đ?&#x2018;Ą + 0.1đ?&#x2018;&#x201E; + đ??´đ?&#x2018;&#x2019;đ?&#x2018;Ľđ?&#x2018;?(â&#x2C6;&#x2019;đ??ľ đ?&#x2018;&#x2013;đ?&#x2018;Ą) Where EO is the battery constant voltage (V), K is the polarization constant (Ah-1), Q is the maximum battery capacity (Ah), it (â&#x2C6;Ť i dt) is the actual battery charge (Ah), R is the internal resistance (Ί), i is the battery current (A), i* is the low frequency current dynamics (A), A is the exponential zone amplitude (voltage drop during the exponential zone) (V), and B is the exponential zone time constant inverse (Ah) â&#x2C6;&#x2019;1. It is implemented using several standard Simulink blocks as well as some of the Sim Power System blocks as shown in Figure 7. The output of this model is a vector containing three signals: state-of-charge (SOC), battery current and battery voltage [12]. đ?&#x2018;&#x2030;
= đ??¸ â&#x2C6;&#x2019;đ??ž
Fig. 7 - Subsystem implementation of the LiIon battery model The main feature of this battery model is that the parameters can easily be deduced from a manufacturerâ&#x20AC;&#x2122;s discharge curve. D. The PEMFC stack model The fuel cell stack voltage (Vfc) is described as đ?&#x2018;&#x2030; = đ??¸
â&#x2C6;&#x2019; đ?&#x2018; đ??´đ?&#x2018;&#x2122;đ?&#x2018;&#x203A;
Ă&#x2014;
â&#x2C6;&#x2019;đ?&#x2018;&#x2026;
đ??ź
Where Eoc is the open circuit voltage (V), N is the number of cells, A is the Tafel slope (V), Io is the exchange current (A), Ifc is the fuel cell current (A), Td is the response time (sec), and Rohm is the internal resistance (Ί). The dynamic model of PEMFC is built and implemented using ISBN-978-81-932091-2-7
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MATLAB/Simulink. The modified fuel cell model combines the features of chemical [13] and electrical models [14]. Hence, itâ&#x20AC;&#x2122;s suitable for electrical simulation programs and can represent the effect of operating parameters on the stack. The model is implemented as shown in Figure 8. Fuel cell manufacturers provide specifications of their stacks which include the peak power, polarization curve, number of cell, etc. The PEMFC stack model is modified to include a fuzzy logic temperature controller are used to obtain the models parameters.
III.
Fig. 8 - Subsystem implementation of the PEMFC stack model Hybrid Systems Energy Controller Based on Artificial Intelligence A novel adaptive scheme for energy management in stand-alone hybrid power systems, the proposed management system is designed to manage the power flow between the hybrid power system and energy storage elements in order to satisfy the load requirements based on artificial neural network (ANN) and fuzzy logic controllers [15]. The method offers an on-line energy management by a hierarchical controller between four energy sources comprises photovoltaic panels, wind turbine, battery storage, and proton exchange membrane fuel cell [16]. The proposed method includes a MPPT controller in the first layer, to achieve the maximum power point (MPP) for different types of PV panels; two different
techniques will be presented (P&O and neural network). In the second layer, an advance fuzzy logic controller will be developed to distribute the power among the hybrid system [17] and to manage the charge and discharge current flow for performance optimization. Finally in the third layer, smart controllers are developed to maintain the stability of the PEMFC temperature and to regulate the fuel cell/battery set points to reach best performance [18]. Figure 9 shows the proposed control structure for the hybrid generation system.
Fig. 9 - Block diagram of the proposed system IV. Simulation Discussion The dynamics simulation models for each of the: PV array, wind turbine, PEM fuel cell, and LiIon battery were explained and shown. Afterward, an optimized energy management [19-22] based on a hierarchical controller has been implemented to satisfy important objectives such as: optimal operation of PV panel, battery charge balance, optimal operation of FC, and load. Here, P&O algorithm with linear and non-linear controllers are provided for a comparison with the proposed MPPT controller system [23-29]. ISBN-978-81-932091-2-7
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V. Conclusion [9] The analysis of simulation results has shown that the adaptive algorithm developed is suitable for stand-alone hybrid power systems. This control [10] algorithm is capable of: Extracting maximum power from the PV panels with tracking efficiency exceed 94.5%. Splitting the power between the power sources [11] to sustain the efficiency of the system. Regulating the PEMFC on/off status according to external environmental changes and to load [12] demand expectation Optimizing the generating performance of the PEMFC by maintaining the temperature stable and equal to the stack operating temperature (e.g. 65%). [13]
References [1]
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N. Shaheen, N. Javaid, Z. Iqbal, K. Muhammad, K. Azad and F. A. Chaudhry, "A Hybrid Algorithm for Energy Management in Smart Grid," Network-Based Information Systems (NBiS), 2015 IEEE 18th International Conference on, Taipei, 2015, pp. 58-63. Ahmed, N.A., Al-Othman, A.K., & Al-Rashidi, M.R. (2011) Development of an Efficient Utility Interactive Combined Wind/Photovoltaic/Fuel Cell Power System with MPPT and DC Bus Voltage Regulation, Electric Power Systems Research, 81, (5), pp. 1096–1106 Ahmed, N.A., Miyatake, M., & Al-Othman, A.K. (2008) Power Fluctuations Suppression of Standalone Hybrid Generation Combining Solar PV/Wind Turbine and Fuel Cell Systems, Energy Conversion and Management, 49, (10), pp. 2711-2719. Hau, E. (2006). Wind Turbines: Fundamentals, Technologies, Application, Economics, 2nd edn. Springer, Berlin, Germany. Hwas, A., & Katebi, R. (2012) Wind Turbine Control using PI Pitch Angle Controller, IFAC Conference on Advances in PID Control, Brescia, Italy. Muljadi. E., & Butterfield, C.P. (2001) Pitch-Controlled Variable Speed Wind Turbine Generation, IEEE Trans. Industry Applications, 37, (1), pp. 240– 246. Borowy, B.S., & Salameh, Z.M. (1996) Methodology for Optimally Sizing the Combination of a Battery Bank and PV Array in a Wind/PV Hybrid System, IEEE Trans. Energy Conversion, 11, (2), pp. 367–373. Qiuli, Y., Srivastava, A.K., Choe, S.-Y., Gao, W. (2006) Improved Modeling and Control of a PEM Fuel Cell
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Power System for Vehicles, Southeast Con, 2006. Proceedings of the IEEE, pp. 331 – 336 Souleman, N.M., Tremblay, O., & Dessaint, L.-A. (2009) A Generic Fuel Cell Model for the Simulation of Fuel Cell Power Systems, IEEE Power & Energy Society General Meeting, pp. 1-8. Natsheh, E.M., & Albarbar, A. (2013) Hybrid Power Systems Energy Controller Based on Neural Network and Fuzzy Logic, Smart Grid and Renewable Energy, 4, (2), pp. 187-197. Wang, C., & Nehrir, M.H. (2008) Power Management of a Stand-alone Wind/PV/Fuel Cell Energy System. IEEE Trans. Energy Conversion, 23, (3), pp. 957-967. Esram, T., Urbana, I.L., Chapman, P.L. (2007) Comparison of Photovoltaic Array Maximum Power Point Tracking Techniques, IEEE Trans. Energy Conversion, 22, (2), pp. 439 – 449. Celik, A.N. (2003) TechnoEconomic Analysis of Autonomous PV–Wind Hybrid Energy Systems using Different Sizing Methods, Energy Conversion and Management, 44, (12), pp. 1951-1968. Das, D., Esmaili, R., Longya, X., & Nichols, D. (2005) An Optimal Design of a Grid Connected Hybrid Wind/Photovoltaic/Fuel Cell System for Distributed Energy Production, 31st Annual Conference of IEEE, Industrial Electronics Society, Raleigh, NC. Dursun, E., & Kilic, O. (2012) Comparative Evaluation of Different Power Management Strategies of a Standalone PV/Wind/PEMFC Hybrid Power System, Electrical Power and Energy Systems, 34, (1), pp. 81-89. Kim, S.K., Jeon, J.H., Cho, C.H., Kim, E.S., & Ahn, J.B. (2009) Modeling and Simulation of a Grid-Connected PV Generation System for Electromagnetic Transient Analysis, Solar Energy, 83, (5), pp. 664- 678. Villalva, M.G., Gazoli, J.R., & Filho, E.R. (2009) Comprehensive Approach to Modeling and Simulation of Photovoltaic Arrays, IEEE Trans. Power Electronics, 24, (5). pp 1198–1208. Hajizadeh, A., & Golkar, M.A. (2007) Intelligent Power Management Strategy of Hybrid Distributed Generation System. International Journal of Electrical Power & Energy Systems, 29, (10), pp. 783–795. Kim, M., Sohn, Y.-J., Lee, W.-Y., & Kim, C.-S. (2008) Fuzzy Control Based Engine Sizing Optimization for a Fuel Cell/Battery Hybrid Mini-Bus. Journal of Power Sources, 178, (2), pp. 706-710. C. H. Cai, D. Du and Z. Y. Liu, "Battery state-of-charge (SOC) estimation using adaptive neuro-fuzzy inference system (ANFIS)," Fuzzy Systems, 2003. FUZZ '03. The 12th IEEE International Conference on, 2003, pp. 10681073 vol.2.
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Comparative study of ATSMC and PTMC for a Single Phase SAPF Seema Agarwal*1, Seemant Chourasiya*2 , D. K. Palwalia*3, Department of Electrical Engineering, Rajasthan Technical University, Kota, INDIA Corresponding Author: seema10dec@gmail.com Abstract This paper describes the analysis, design, simulation and comparison of the Precise Total Multivariable Control (PTMC) theory and Adaptive Total Sliding Mode Controller (ATSMC) to a single phase shunt dynamic power filter(SPSDPF) to enhance the power quality by reducing harmonic distortions of electrical system. The aim of this paper is to show the comparison of the PTMC and ATSMC theory and find out which theory is better for the reduction of harmonics. These controllers are implemented and designed in MATLAB 2012a. MATLAB/SIMULINK Results are provided in MATLAB 2012a. Keywords:- Precise Total Multivariable Control, Adaptive Total Sliding Mode Controller, Shunt dynamic power filter, Harmonic Elimination. INTRODUCTION Nowadays the use of non-linear load is increased rapidly in industry and in electronic equipment. All the power electronic devices are considered as nonlinear load. Television, Refrigerator, Air Conditioner, Inverters, Printers, Fax machines are some example of non-linear load [1]. Increased use of non-linear load has increased the amount of distorted currents on electrical system. Therefore, interest has been shown as to the effect of power factor and the extent of harmonics currents being generated and injected in power lines. Traditionally, passive filters have been used to compensate voltage and current harmonics generated by constant non-linear loads. Passive power filters provide low impedance path for distorting harmonics in voltage and current, resulting in improvement of power quality. Passive filters can be easily designed and have low cost. However, there are some drawbacks of passive filters such as mistuning, resonance, bulky implementation, no possibility of using same power filter for different load. [2]-[3]. These drawbacks of passive filters can be overcome by use of active power filters. Several control topologies functioning with power semiconductor switches have been developed for high-quality requirement. These topologies are designed to call off the original voltage and current harmonics deformation by injecting the same detected deformation, but with reverse polarity, thereby recuperating the power quality. Active power filters are connected between source and load. Depending
I.
upon the type of connection it can be classified as series dynamic power filter, shunt dynamic power filter and hybrid dynamic power filter. Shunt active power filters are most widely used solution to reduce current harmonics, while series active power filters are used to reduce voltage harmonics. Universal active power filters are used current harmonics as well as voltage harmonics. Shunt active power filters are usually applied to three phase systems whereas single phase active filters can be applied in adjustable speed motor drive. Different control methods have been reported to control shunt active power filters. These can be classified as: 1. Time-Domain Control Techniques 2. Frequency-Domain Control Techniques Both time-domain and frequency-domain control techniques have well-known disadvantages as these provide non-linear dynamics of the closed loop system. Also, some advance control methods have been reported, such as sliding mode control, artificial neural networks, and optimization [4]- [9]. Of the above-mentioned control methods, the sliding mode control have been extensively applied to the power converters because it has natural tendency to control time varying topologies. Sliding mode control is the nonlinear control strategy. The principle for applying sliding mode control strategy is to propose a sliding surface or switching function. Sliding mode control has inherent characteristics such as insensitivity to ISBN-978-81-932091-2-7
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system parameters variation, robustness and simple control implementation. In this study, sliding mode control (SMC) is proposed which leads to sliding surface which is linear combination of system state variables and the generated references. This control design results in sliding mode controller, which makes the system robust, insensitive to system parameter variation and simple implementation. Further, PTMC is proposed using sliding mode controller which simplifies the procedure to convert non-linear system to normal system. The comparison of ATSMC with PTMC is shown in this work. II. STUDY OF ADAPTIVE TOTAL SLIDING MODE CONTROLLER The main aim of this part of paper is to present an efficient design, mathematical analysis of shunt dynamic power filter and design of Adaptive Total Sliding Mode Controller A. Active Mathematical Modelling of shunt dynamic power filter To analyze the operational mode of shunt dynamic power filter, we define a switching function represented as: 1 if T is ON 0 if T is OFF Here â&#x20AC;&#x2DC;iâ&#x20AC;&#x2122; can be given values from (1 to 4) each representing the switch number. The two switches from the similar segment of the dynamic power filter must operate harmonizing. Therefore, we can write: U + U = 1 and U + U = 1 (1)
v = (U + U â&#x2C6;&#x2019; 1)V (3) The current curving through filter capacitor (IC) can be written as: I = (U + U â&#x2C6;&#x2019; 1) Ă&#x2014; I (4) From expressions of vx (3) and IC (4), the dynamic state equations for the inductor current and capacitor voltage are as given below: L = đ?&#x2018;&#x2030; â&#x2C6;&#x2019; đ??ź đ?&#x2018;&#x2026; â&#x2C6;&#x2019; (đ?&#x2018;&#x2C6; + đ?&#x2018;&#x2C6; â&#x2C6;&#x2019; 1)đ?&#x2018;&#x2030; (5) C = (U + U â&#x2C6;&#x2019; 1)I (6) Here VS is the source voltage. Let U + U â&#x2C6;&#x2019; 1 = U, the dynamic state model of shunt active power filter becomes: = (V â&#x2C6;&#x2019; I R â&#x2C6;&#x2019; UV ) (7) = UI (8)
U =
Fig.1. Shunt dynamic power filter v = (U U â&#x2C6;&#x2019; U U )V (2) From equation (1) and (2) we get
Fig.2. Block Diagram of Shunt dynamic power filter
Fig.3. Sliding surface (a) Stable system (b) Unstable system B. Adaptive Total Sliding Mode Control Strategy The controller consists of two control loops. Outer voltage loop regulates the capacitor voltage and inner current loop tracks the reference current signal. To control the DC capacitor voltage PI controller is used and ISBN-978-81-932091-2-7
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inductor current is controlled by the use of Sliding Mode control strategy. The performance of the controller is improved by proposing a control algorithm based on sliding surface which depends on source current (IS). Assume (VDC, IS) be the reference values of filter capacitor voltage and source current. The reference values assumed above are also known as equilibrium points of the control system. Now we calculate the error signal or error function đ?&#x2018;&#x2019; = đ??ź â&#x2C6;&#x2019; đ??ź â&#x2C6;&#x2014; = 0 which represents the sliding surface. Also, it is found that system has steady state current error. So as to minimize the steady state error an integral term is introduced given by đ?&#x2018;&#x2019; = â&#x2C6;Ť đ?&#x2018;&#x2019; . đ?&#x2018;&#x2018;đ?&#x2018;Ą. The proposed sliding surface or sliding function is given by: S = e + Îťe Or S = e + Îť â&#x2C6;Ť e (9) Where đ?&#x153;&#x2020; is a control parameter also known as sliding coefficient? Positive values of sliding surface coefficient (đ?&#x153;&#x2020;) ensures stability of active power filter. After deriving the sliding mode surface, now our aim is to define the control law based on three conditions. These conditions are as follows Reaching Condition, Existing Condition, Stability Condition. The inequality which satisfies the existing and reaching condition of the system is given by: dS lim S. <0 â&#x2020;&#x2019; dt C. Controller Design and Reference Current Calculation In SM controller in order to satisfy the existence condition we usually determine as following: 1 if S>0 U = 0 if S=0 â&#x2C6;&#x2019;1 if S < 0
applying the control law given in equation 4. Switches of one leg of APF (T3,T4) operates at source voltage frequency and that of other leg(T1,T2)operate at high frequency. The control algorithm U makes the state trajectory to reach the sliding surface in finite time and then slides along the surface towards equilibrium point exponentially. The complete analogy SM controller for single phase shunt APF is shown in fig. 4. Fundamental component of the gate pulses to switch is in same phase to that of source voltage (Vs). So a band pass filter can be used to generate the fundamental component of gate pulse by filtering its harmonics. The characteristics of band pass filter have a significant effect on the active power filter performance. The bandwidth should be small enough to sufficiently attenuate the harmonic components of the reference current. The capacitor voltage is put through a RC low pass filter which yields the average capacitor voltage. This quantity is compared to the reference capacitor voltage, with the difference driving the PI controller. The output of the PI controller is a slow varying variable which is the peak value of reference source current. This implies that the output of PI controller gives sum of peak value of fundamental load current and the peak value of source current required to compensate the real power loss in filter capacitor. As a result, this slow varying variable is multiplied with the output of band pass filter to generate the desired reference source current. As band pass filter is used to calculate reference current, small variation in amplitude of source voltage does not affect reference source current. This is why this active filter is applicable for both distorted and nominal source. III. STUDY OF PRECISE TOTAL MULTIVARAIBLE CONTROL THEORY VIA SLIDING MODE CONTROL The main motive of this segment is to present an efficient design procedure of precise total multivariable control law by combining it with sliding mode control theory to get better results. Fig. 4. Adaptive total sliding mode controller for A. Multivariable linearization: shunt apf In multivariable linearization non-linear The sign of should be controlled to satisfy the characteristics of the electrical system is transformed into a linear characteristics and then existence condition. This can be done by ISBN-978-81-932091-2-7
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linear control techniques are used to control the B. Control Design: whole non-linear electrical system. The stability of the electrical system is Taking into consideration a non-linear singleconformed if the coefficients K1 and K2 of the input single-output (SISO) electrical system sliding surface are always positive and greater . than zero. The system has following dynamics: x ď&#x20AC;˝ f ( x ) g ( x ).U đ?&#x2018;&#x2019;Ě&#x2C6; + đ??ž . đ?&#x2018;&#x2019;Ě&#x2021; + đ??ž . đ?&#x2018;&#x2019; = 0 ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC; ď&#x20AC;¨ď&#x20AC;ąď&#x20AC;°ď&#x20AC;Šď&#x20AC; (16) đ?&#x2018;&#x152; = â&#x201E;&#x17D;(đ?&#x2018;Ľ) This is exponentially stable if the requirements Where f(x) and g(x) defines smooth vector fields đ??ž , đ??ž â&#x2030;Ľ 0 are accomplished. on Rn, h(x) defines smooth function, Y is system Considering the main function of the shunt output and U is the control input variable. active power filter is to shape the line current to Relative degree is a very important theoretical be in same phase as the line voltage. Desired concept in input-output linearization which is behaviour of the line current can be derived as interrelated to the numeral of epoch the system follows output Y to be differentiated, for the đ?&#x2018;&#x2013; = đ?&#x2018;&#x2DC;. đ?&#x2018;Ł input to be appear in the output equation (17) đ?&#x2018;&#x152;Ě&#x2021; = â&#x2C6;&#x2021;â&#x201E;&#x17D;(đ?&#x2018;&#x201C; + đ?&#x2018;&#x201D;. đ?&#x2018;&#x2C6;) = đ??ż â&#x201E;&#x17D;(đ?&#x2018;Ľ ) + đ??ż â&#x201E;&#x17D;(đ?&#x2018;Ľ ). đ?&#x2018;&#x2C6; where k is output of PI controller and sluggish (11) time varying factor based on power demand. Where L h(x) and L h(x) are the Lie algebra By the correlation between line current, filter current and load currents, we can derive the derivatives of h(x) with reverence to current reference expression as f(x) and g(x) . If the virtual degree r of the đ?&#x2018;&#x2013; â&#x2C6;&#x2014; = đ?&#x2018;&#x2DC;. đ?&#x2018;Ł â&#x2C6;&#x2019; đ?&#x2018;&#x2013; electrical system coincides with the system order (18) (r=n), we must differentiate r times the system Hence, we can write the expression of error output, i.e. function as: đ?&#x2018;&#x152; = đ??ż â&#x201E;&#x17D;(đ?&#x2018;Ľ ) đ?&#x2018;&#x201C;đ?&#x2018;&#x153;đ?&#x2018;&#x; đ?&#x2018;&#x17D;đ?&#x2018;&#x2122;đ?&#x2018;&#x2122; đ?&#x2018;&#x2DC; < đ?&#x2018;&#x; â&#x2C6;&#x2019; 1 đ?&#x2018;&#x2019; = â&#x2C6;Ť đ?&#x2018;Ł (đ?&#x2018;&#x2013; â&#x2C6;&#x2019; đ?&#x2018;&#x2DC;đ?&#x2018;Ł )đ?&#x153;&#x2022;đ?&#x2018;&#x; (12) (19) and from the above equation the sliding surface đ?&#x2018;&#x152; = đ??ż â&#x201E;&#x17D; (đ?&#x2018;Ľ ) + đ??ż đ??ż â&#x201E;&#x17D;(đ?&#x2018;Ľ ). đ?&#x2018;&#x2C6; can be derived as: (13) Which shows that đ??ż đ??ż â&#x201E;&#x17D; (đ?&#x2018;Ľ ) = 0 for all (k < r-1) đ?&#x2018; = đ?&#x2018;Ł (đ?&#x2018;&#x2013; â&#x2C6;&#x2019; đ?&#x2018;&#x2DC;đ?&#x2018;Ł ) + đ??ž đ?&#x2018;Ł (đ?&#x2018;&#x2013; â&#x2C6;&#x2019; đ?&#x2018;&#x2DC;đ?&#x2018;Ł )đ?&#x153;&#x2022;đ?&#x153;? and đ??ż đ??ż â&#x201E;&#x17D;(đ?&#x2018;Ľ ) â&#x2030; 0 đ?&#x2018;&#x201C;đ?&#x2018;&#x153;đ?&#x2018;&#x; (đ?&#x2018;&#x; = đ?&#x2018;&#x203A;). Hence the + đ??ž đ?&#x2018;Ł (đ?&#x2018;&#x2013; system linearization can be done by means of the subsequent input conversion. â&#x2C6;&#x2019; đ?&#x2018;&#x2DC;đ?&#x2018;Ł )đ?&#x153;&#x2022;đ?&#x153;? (20) đ?&#x2018;&#x2C6;= [đ?&#x2018;Ł â&#x2C6;&#x2019; đ??ż â&#x201E;&#x17D;(đ?&#x2018;Ľ)] ( ) The key aim in derivation of sliding mode (14) controller is to fulfil the reaching surface which provides a linear bond linking the condition which ensures the existence of the electrical system output Y and the control input sliding regime on a sliding surface. The reaching đ?&#x2018;Ł: surface condition can be given by: đ?&#x2018;Ś = đ?&#x2018;Ł đ?&#x2018; . đ?&#x2018; Ě&#x2021; < 0 (15) The control law is obtained as Still, the electrical system cannot be liberalized 1, for đ?&#x2018; > 0 đ?&#x2018;&#x2C6;= when the virtual degree of an electrical system is 0, for đ?&#x2018; < 0 not more than the order of the electrical system. In this case, system is partially liberalized and the part of the system which is set aside of the linearization process should be confirmed [10]. This is the case for reflection of steadiness of internal dynamics of electrical system. ISBN-978-81-932091-2-7
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VS IS
I S*
Low pass fliter
Sin wt Unit vector generation
Sliding Surface eqn. (19)
Sin wt
S
clock
VS
Vc
LOGIC CIRCUIT
PI Controller
T1 T2
T3
Vcref T4
Fig.5 Multivariable Controller Design IV. SIMULATION RESULTS To check the robustness and efficiency of the proposed analog SM controller, the complete shunt APF system is simulated using MATLAB/SIMULINK. The diode bridge rectifier having 500-ΟF capacitor is the nonlinear load used in parallel with a 45-Ί resistor at its output side. The system parameters used in the simulation are given in Table 1. Cut-off frequency of RC low pass filter has been set as 80 Hz. Cut-off frequency and bandwidth of band pass filter have been set as 50 Hz and 6 Hz respectively. Table 1. SYSTEM PARAMETERS L= 5mH Vref = 200V C = 1100¾F
đ?&#x2018;&#x2030;
= 110 đ?&#x2018;&#x2030; đ?&#x2018;&#x201C; = 50đ??ťđ?&#x2018;§ đ?&#x2018;&#x201C; = 40đ?&#x2018;&#x2DC;đ??ťđ?&#x2018;§
đ?&#x153;&#x2020; = 2000đ?&#x2018;&#x2020; đ??ž = 0.5 đ??ž = 10
The THD of the source voltage under ideal condition is found to be 0.11%. Similarly, the THD of the load current considering up to 30th harmonics is calculated as 68.77%. Simulated load current and source voltage waveforms are shown in Fig. 6. It is cleared by application of proposed controller, the source current THD is reduced to 4.6%. Fig. 7 shows source current and source voltage waveforms of the proposed analog SM controller.
Figure 6. load Current and Source Voltage
Fig- 7. Source current, Source voltage and Filter current with proposed adaptive sliding mode control
Fig. 8.Dc link capacitor voltage Finally, this part of paper provides simulation results to validate the proposed multivariable control theory. All the results are validated using MATLAB/SIMULINK 2012a.The various parameters used in designing of shunt dynamic power filter are shown in Table II given below: Table II PARAMETERS OF THE DYNAMIC POWER FILTER Parameter VS fS L C RO CO RS K1 K2 KP KI VC* fsampling
Value 110 VRMS 50Hz 6mH 1500ÂľF 50â&#x201E;Ś 500 ÂľF 5â&#x201E;Ś 5000 16650 0.50 10 200 40KHz
The cut-off frequency used in low pass filter is 78 Hz. The proposed multivariable controller reduces the harmonics by less than 5%. The total harmonic distortion in source current after use of this controller is 2.78%.These results are verified for time period from 0.12seconds and up to 4 cycles. The simulation results of proposed controller are verified in MATLAB/SIMULINK 2012a. These are given below: ISBN-978-81-932091-2-7
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[3] Fig.9. Load current and Source voltage
[4]
Fig.10.Simulation results of proposed controller (a) Source Current, (b) Source voltage (c) filter current
[5]
[6] Fig.11 Dc link Voltage The table given below shows the comparison of the proposed control scheme: Harmonic (A rms) THD% iL 67% Is(proposed 2.78% controller) CONCLUSION This paper investigates the ATSMC and PTMC to a single-phase shunt dynamic filter by implementing the sliding mode control theory. The comparison shows that PTMC is better in comparison with ATSMC. Its ability to reduce harmonics is much better. References
V.
[1]
[2]
P. R. Stratford, “Harmonic pollution on power systems—A change in philosophy,” IEEE Trans. Ind. Appl., vol. IA–16, pp. 617–623, 1980. J. S. Subjak and J. S. McQuilkin, “Harmonics—Causes, effects,
[7]
[8]
[9]
measurements, and analysis: An update,” IEEE Trans. Ind. Appl., vol. 26, no. 6, pp. 1034–1042, Nov.–Dec. 1990. M. E. Amoli and T. Florence, “Voltage, current harmonic control of a utility system—A summary of 1120 test measurements,” IEEE Trans.Power. Del., vol. 5, no. 3, pp. 1552–1557, Jul. 1990. E. Emanual, J.A. Orr, D.Cybanki, and E.M Gulchenski., “A survey of harmonic voltages, currents at the customer’s bus,” IEEE Trans. Power. Del., vol. 8, no. 1, pp. 411–421, Jan. 1993. Mansoor, W. M. Grady, P. T. Staats, R. S. Thallam, M. T. Doyle, and M. J. Samotyj, “Predicting the net harmonic currents produced by large numbers of distributed single-phase computer loads,” IEEE Trans. Power. Del., vol. 10, no. 4, pp. 2001–2006, Oct. 1994. M. El-Habrouk, M. K. Darwish, and P. Mehta, “A survey of active filters and reactive power compensation techniques,” IEE Power Electron. Variable Speed Drives, pp. 7–12, 2000. S. Buso, L. Malesani, and P. Mattavelli, “Comparison of current control techniques for active filter applications,” IEEE Trans. Ind. Electron., vol. 45, no. 5, pp. 722–729, Oct. 1998. Seemant Chourasiya, Seema Agrawal, “A REVIEW: Control Techniques for Shunt Active Power Filter for Power Quality Improvement from Non-Linear Loads”, International Journal Electrical Engineering, 2015, Vol. 6, No.10, pp. 2028-2032. Seema Agrawal, Prakash Kumar, D.K Palwalia, “Artificial neural network based active power filter “, IEEE 7th international conference PIICON 2016, pp. 1-6 .
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Combined Vector and Direct Power Control of Doubly Fed Induction GeneratorBased Wind Turbines: A Review Paper Malek Mahammadrizwan M., N. G. Mishra Department of Electrical Engineering, BVM Vallabh Vidyanagar, Gujrat India Corresponding Author: rizwanmalek1995@gmail.com
ABSTRACT In this paper a new innovative combined vector and direct power control (CVDPC) strategy is proposed for the rotor side converter (RSC) of doubly fed induction generators (DFIGs)-based wind energy generation system. The direct control of stator active and reactive power based strategy is used by selection of appropriate voltage vectors on the rotor side. It is observed that the initial rotor flux has no effect on the changes of the stator active and reactive power. The proposed method only makes use of the estimated stator flux in order to overcome the difficulties associated with rotor flux estimation. The proposed DPC method requires only one machine parameter i.e. .the stator resistance which has negligible impact on the system performance. Simulation results on a 9-MW wind farm consisting of six 1.5-MW DFIG-based wind turbines shows that the effectiveness and robustness of the proposed control strategy during variations of active and reactive power, rotor speed, machine parameters, and converter dc link voltage. Keywords-Direct power control (DPC), doubly fed induction generator (DFIG), direct torque control, voltage source converter, voltage vector. will operate only a sub synchronous speed I.INTRODUCTION ranges, the GSC might be replaced with a threeDoubly fed induction generator (DFIG) is phase uncontrolled rectifier In the past many suitable choice for variable speed wind turbines. years, a great increase in electrical power Due to the fact that the DFIG is controlled by the demand and depletion of natural resources have rotor circuit and the rotor circuit power made environmental and energy crises. These approximately equal to 30% of the stator circuit have led to an increased need for production of power, DFIG need small-scale power electronic energy from renewable sources so that the world converter when compared with induction wind energy production has grown significantly generators or synchronous generators. Therefore due to cleanness and renewability. Wind power usage of the DFIG in variable speed wind turbine generation is estimated to be 10% of the world’s systems are more efficient [1]. total electricity by the year 2020 and is expected DFIGs stator windings directly connected to the to be double or more by the year 2040 [1]. Wind grid and rotor windings connected to the grid via turbines (WTs), which play a main role in wind a bi-directional backto- back converter as shown energy, are basically divided into fixed and in Fig. 1. The bi-directional back-to- back variable-speed technologies. converter consists of two converters called rotorside converter (RSC) and grid-side converter II.COMBINED VECTOR AND DIRECT (GSC). These two converters are connected to a common DC bus. The rotor side converter is POWER CONTROL used to control the active and reactive power of A. Vector Control the DFIG and controls the power factor of the Vector control is the most popular method used DFIG. On the other hand grid side converter in the Doubly Fed Induction Generator-based keeps the DC bus voltage constant. During the Wind Turbines. In this control method, the stator operations between sub synchronous and super active and reactive powers are controlled synchronous speed ranges, three phase voltage through the rotor current Vector Control. The source converter has to be used as GSC. If DFIG current vector is decomposed into the ISBN-978-81-932091-2-7
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components of the stator active and reactive power in synchronous reference frame. This decouples the active power control from the reactive power control. The stator active and reactive power references are determined by the maximum power point tracking (MPPT) strategy and the grid requirements, respectively. The phase angle of the stator flux space vector is usually used for the controller synchronization. Although, if the stator flux-oriented frame (SFOF) is used, the overall performance of VC will be highly dependent on the accurate estimation of the stator flux position. This can be a critical problem under the distorted supply voltage condition or varying machine parameters. Therefore, in this paper, the statorvoltage-oriented frame (SVOF) is used for the controller synchronization. In order to extract the synchronization signal from the stator voltage signal, a simple phase locked- loop (PLL) system is used. The stator active and reactive powers are as [3]. 3 3 PS ď&#x20AC;˝ Re(VS is *) ď&#x20AC;˝ (Vds ids ď&#x20AC;Ť Vqs iqs ) ----------(1) 2 2 3 3 QS ď&#x20AC;˝ Im(VS is *) ď&#x20AC;˝ (Vqs ids ď&#x20AC;Ť Vds iqs ) --------- (2) 2 2 As the SVOF is used for the controller synchronization, đ?&#x2018;&#x2030;đ?&#x2018;&#x17E;đ?&#x2018; disperse and the stator active and reactive power equations are simplified to 3 Ps ď&#x20AC;˝ Vds ids ---------- (3) 2 ď&#x20AC;3 Qs ď&#x20AC;˝ Vds ids ---------- (4) 2 According to the stator flux equations in the synchronous frame [3], in this condition, the stator currents can be written as ď&#x20AC;L ids ď&#x20AC;˝ m idr ---------- (5) Ls ď&#x20AC;L V iqs ď&#x20AC;˝ m (iqr ď&#x20AC;Ť ds ) ---------- (6) Ls ď ˇs Lm Substituting (5) and (6) into (3) and (4) yields ď&#x20AC;3Lm Ps ď&#x20AC;˝ Vds idr ---------- (7) 2 Ls
3Lm V Vds (iqr ď&#x20AC;Ť ds ) ---------- (8) 2 Ls ď ˇs Lm So, the stator active and reactive powers are controlled through đ?&#x2018;&#x2013;đ?&#x2018;&#x2018;đ?&#x2018;&#x; andđ?&#x2018;&#x2013;đ?&#x2018;&#x17E;đ?&#x2018;&#x;, respectively. The block diagram of the RSC-based Vector Control is shown in Fig. 1. As shown in Fig. 1 schematic block diagram for the rotor-side converter control of the DFIG. The references q-axis rotor current đ?&#x2018;&#x2013; â&#x2C6;&#x2014; can be obtained either from an outer speed control loop or from a torque imposed on the machine. These two options may be termed a speedcontrol mode or torque-control mode for the generator, instead of regulating the active power directly. For speed-control mode, one outer Pl controller is to control the speed error signal in terms of maximum power point tracking Furthermore, another PI controller is added to produce the reference signal of the d-axis rotor current component to control the reactive power required from the generator. Assuming that all reactive power to the machine is feed by the stator, the reference value đ?&#x2018;&#x2013; * may set to zero. Rotor excitation current control is realized by controlling rotor voltage. The đ??ź and đ??ź error signals are processed by associated PI controllers to give đ?&#x2018;&#x2030; and đ?&#x2018;&#x2030; respectively. Qs ď&#x20AC;˝
Figure 1. Block diagram of the vector control strategy of RSC. B.
Direct Power Control
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In the Direct Power Control method, the stator active and reactive powers are controlled directly and the current control loop is eliminated. The principles of DPC can be explained by the following stator active and reactive power equations [7] Ps =
3Lms s r sin ----------(9) 2 Ls Lr
3s L s s m r cos ----------(10) 2 Ls Lr By assuming constant magnitude for the stator and rotor flux, the derivative of (9) can be represented approximately as Qs =
dPs 3Lms s r cos ----------(11) dt 2 Ls Lr Equation (11) shows that the stator active power dynamics depends on the variation of δ. Therefore, the fast-active power control can be achieved by rapidly changing δ. By assuming constant magnitude for the stator flux and δ the derivative of (10) can be represented approximately as d r dQs 3Lms s cos ---------- (12) dt 2 Ls Lr dt
reactive power control can be achieved by rapidly changing the rotor flux magnitude. The variation in the rotor flux can be carried out by applying the appropriate inverter voltage vectors to the rotor windings to rotate the rotor flux linkage vector. The rotor voltage equation can be represented and approximated in a short interval of ⵠt as d r Vr Rr ir Vr r Vr gt ---------dt (13) The six inverter voltage vectors can be appropriately used to control the position and value of the rotor flux’s by knowing the sector in which 'r is located. The block diagram of the direct power-controlled RSC is shown in Fig. 2.
III.Simulation and results In this section simulation study, using MATLAB/Simulink, is simulated on a 9-MW wind farm consisting of six 1.5-MW DFIGbased WTs to compare the performance of the proposed CVDPC method with both Vector Control and Direct Power Control strategies. Fig. 5
Figure 3. Schematic diagram of the proposed simulated system.
Figure 2. Block diagram of the direct power control strategy of RSC. Equation (12) shows that the stator reactive power dynamics depend on the magnitude variation of the rotor flux. Therefore, the fast-
IV.Conclusion In this paper, considering the vector control and direct power control method a new approach to combined control scheme based on the common basis of vector control method and direct power control method has been presented for the rotor ISBN-978-81-932091-2-7
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side convertor of the doubly fed induction generator. In result, the proposed combined vector direct power control method gives a compromise of the advantages of these two methods.
the variation of the machine parameter. By implementing CVDPC control method gives lower power ripple and also high dynamic response.
Figure 4. Simulation results when the wind speed changes from 15 to 10 m/s.
In the FFT analysis results shows that VCDPC having less THD than the VC method. Also provides the decoupling and robustness against
Figure 5. Simulation results when Rr is changed. ISBN-978-81-932091-2-7
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V.REFERENCES 1. Sevki Demirbas, Sertac Bayhan, “Active and Reactive Power Control of Doubly Fed Induction Generator Using Direct Power Control Technique”, 4th International Conference on Power Engineering, Energy and Electrical Drives. 2. Iwanski G., Koczara W., “Sensorless Direct Voltage Control Method for Stand-Alone Slip-Ring Induction Generator”, IEEE Transactions on Industrial Electronics, 54(2): 1237-1239, 2007. 3. Demirba, Bayhan S., “Grid Synchronization of Doubly Fed Induction Generator in Wind Power Systems”, III. International Conference on Power Engineering Energy and Electrical Drives, POWERENG 2011, Malaga, Spain, 2011. 4. Jafar Mohammadi, Sadegh Vaez-Zadeh, Saeed Afsharnia, and Ehsan Daryabeigi, “A Combined Vector and Direct Power Control for DFIG-Based Wind Turbines”, IEEE TRANSACTIONS ON SUSTAINABLE ENERGY, VOL. 5, NO. 3, JULY 2014 5. G. Abad, J. Lopez, M. A. Rodriguez, L. Marroyo, and G. Iwanski, “Doubly Fed Induction Machine Modeling and Control for Wind Energy Generation Applications” Hoboken, NJ, USA: Wiley, 2011.
List of Figures: Figure 1. Block diagram of the vector control strategy of RSC. Figure 2. Block diagram of the direct power control strategy of RSC. Figure 3. Schematic diagram of the proposed simulated system. Figure 4. Simulation results when the wind speed changes from 15 to 10 m/s. Figure 5. Simulation results when Rr is changed.
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Biomass-Diesel based Hybrid Electrical Supply System for Small Network Praful Patidar, Chanakya B. Bhatt Government Engineering College Banswara, India-327001 Nirma University Ahmedabad, India Corresponding Author: prafulpap35@gmail.com
ABSTRACT In present time, distributed generation is very common concern to the researchers. Many researchers working related to micro grid and distributed generation. In rural areas, wastage is available in form of rice husks, sugarcane bagasse (for biomass), animal dung (for biogas) etc. It can be utilized in form of renewable bio energy to produce electrical energy. Main idea in this project is to use waste electrical energy and feed rural areas as well as vital loads. Biomass producer gas can be used in a hybrid system along with diesel to full the power need of rural area with less carbon emission. It can be standalone or grid connected system. Dual fuel generator with diesel and biogas/syngas is a favourable solution for emergency power backup and energy crisis. In this paper, diesel generator set operate in emergency condition and supply the vital load when grid/renewable source fault occurs and analyse the effect of DG set with stand-alone condition. This is done by developing numerical models for the simulation of the operating diesel generators as a back-up energy source in hybrid power systems. The dynamic analysis is completed by the help of Simulation tool.
1.
INTRODUCTION
The increasing demand for energy, the continuous reduction in existent resources of fossil fuels and the growing concern regarding environmental pollution have compelled mankind to explore new production technologies for electrical energy using clean renewable sources such as biogas and biomass energy, solar energy, wind energy, etc. Among the electric power technologies using renewable sources are clean, green, silent and reliable, with low maintenance costs. Along with these advantages, how-ever, electric power production systems using as primary sources exclusively solar and wind energy pose technical problems due to uncontrollable wind speed fluctuations and to the day night and summer winter alternations. As a consequence, in continuous region, the power supply continuity of a local grid should be backed-up by other reliable and non- fluctuate sources of primary energy, such as diesel generator sets. Such systems, designed for the decentralized production of electric power using combined sources of primary energy, are called hybrid systems. Diesel generator sets also used for emergency region in conventional sources energy like nuclear plant. Diesel generator set used for feed power in isolate region as well as an emergency region.
The increased interest in using of diesel generator sets as the main energy source in isolated areas or as an stand by source in the case of renewablebased power systems can be observed by the great number of papers and studies carried out in this area. The research conducted in this domain refers to aspects such as island operations of diesel generator sets [3], simulations of diesel/pv/wind hybrid power systems [4][5],etc.
Figure1: Biomass-Diesel based small Network
2. Utilization of Biomass as Engine Fuel As of 31 January 2014, India had an installed capacity of about 31.15 GW of non-conventional renewable technologies-based electricity, about 13.32 % of its total. Total Installed Capacity of Bio Energy as of 31, January 2014 is 4479.85 MW. Table 2.1: Overview of biomass energy Source
Type
Capacity ISBN-978-81-932091-2-7
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Biomass Power and Gasification
Gridconnected
1285.60 MW
GridBagasse Cogeneration connected
2512.88 MW
Non - Bagase Cogeneration
Off -grid
517.34 MW
Rural Biomass Gasifier
Off -grid
17.63 MW
Industrial Biomass Gasifier
Off -grid
146.40 MW
India produces about 600 million tonnes of agricultural residues (mainly rice husks, paddy straw, sugarcane waste, wheat residues and cotton stalks), of which 300 million tonnes are unutilized and are disposed of by burning in open fields thus creating environmental hazards. Diesel engine is capable of successful running in duel fuel mode of operation with suitable biomass in gasifier. This study presents engine performance using rice husk, rice straw, cotton stalks and bagasse as biomass fuel in downdraft gasifier in dual fuel mode. Power Generation application on 100 % producer gas based system Rs. 15 lacs per 100 KW.
2.1
Introduction
As the engine had to be fuelled with syngas or biogas, the unit was fed with laboratory blends contained in specific tanks for compressed gasses. In Table 2.2 and 2.3 the standard composition and lower heat content for a syngas and biogas (anaerobic process) are reported, both derived from standard biomass and with the percentage in volume of the different components[6].
CO
CH
2
4
7.0 2.2
H
CO
Others L.H.C MJ=NM 3
2
41.0 23.0 20.0 9.0 13.0 Experimental work on engine
In biomass gasifier (5 kW, Kirloskar, single cylinder, four stroke engine with 1500 rpm), biomass was fed through feed door and stored in hopper (Fig.2.1). Throat (or hearth) ensures relatively clean and good quality gas production. Grate holds charcoal for reduction of partial combustion products while gas outlet is connected with engine via venturi scrubber, separator box cum fine filter and check filter with an air control valve to facilitate running of engine in dual-fuel mode [7]. Table 2.4: Characterization of fuels [4] Calori c value,
Biomass
Ash %
C%
H% N%
Cotton stalks
6.68
43.64
5.81
Bagasse
4.27
44.80
6.20 0.20
44.40 0.01 18.11
Rice husk
17.60
38.30
4.80 0.34
35.45 0.03
14.4
Rice straw
10.70
42.30
5.60 0.90
40.50 0.02
11.7
Wood Chips
3.20
48.60
5.56 0.60
41.46 0.03
17.4
0
O % S % MJ/kg 43.87
0
17.4
Table 2.2: Standard composition for a biogas (Anaerobic) from Biomass CH
CO
4 62.0
Others 2
35.0
3.0
L.H.C MJ=NM3 23.0
Table 2.3: Standard composition for a syngas from biomass
Figure 2.1: Schematic arrangement of experimental set up [4] Dust particle of gas also removed by passing through gas filter. To control of gas valves were provided in passage of gas and air ow. A single cylinder naturally aspirated direct injection fourstroke diesel engine coupled with generator was used for power generation. Dual fuel mode of operation was carried out by supplying gas to ISBN-978-81-932091-2-7
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combustion chamber of engine through inlet manifold. Gas control valve is opened gradually to feed gas into engine. Also, engine governor control knob is closes to dual fuel position, to decrease amount of diesel when sound becomes normal. With rotation of gas valve, optimum adjustment of gas and diesel is made.
2.3
Result and analysis of energy cost
As producer gas is increased, there is a decrease in diesel consumption. Hence, higher diesel substitution in dual fuel mode of operation is achieved opening producer gas valve fully so that higher amount of producer gas ow will replace higher amount of diesel. Sugar cane bagasse fuel replaced maximum diesel (82 %) at 3 kW load followed by cotton stalks fuel (80 %). As gas ow is increased in cotton stalks fuel, diesel substitution varies from 60.58 - 79.79 %, maximum diesel substitution is obtained at full opening of gas ow valve. Wood also replaces a little more diesel (8085%) as both fuels have same characterization properties. Sugar cane bagasse for producer gas generation in gasi er showed maximum diesel substitution (82.1 %) in dual fuel mode. As compared to cotton stalks and sugar cane bagasse, diesel displacement in case of rice husk as fuel is very less (33.36-59.74%), because presence of small quantities of C (38.3 %) and H (4.5%) and also very high ash content, which creates hindrance in producer gas generation. Rice straw gave minimum diesel replacement (47%), due to nitrogen present in rice straw that dilutes producer gas quality and also ash content being very high creating hindrance in production of producer gas. Energy costs (Fig. 2) to produce 1 kWh energy (at 3 kW load), cost associated with drying, collection, storage and transportation of biomass fuels is given as[4] Energy cost (Rs/kWh) = (cost of diesel x diesel consumption) + (cost of biomass x producer gas consumption)
(2.1) Looking into energy costs, sugar cane bagasse is higher than cotton stalks but its
Figure 2.2: Energy cost of fuels [4]
diesel replacement is more than cotton stalks, because cost of bagasse is higher than cotton stalks. Diesel engine generator is capable of successful running in dual fuel mode of operation with suitable biomass in gasifier because of fuel is already available. To produce 1 kWh of energy, 630 ml diesel was used at Rs 19.55. Maximum diesel replacement in dual fuel mode of operation using cotton stalks in gasifier was 80 %. To produce 1 kWh of power energy, cost associated was Rs 4.46. Maximum diesel replacement in dual fuel mode of operation using sugar cane bagasse in gasifier was 82%. To produce 1 kWh of power energy, cost associated was Rs 4.82. Maximum diesel substitution in case of rice husk was 60% and to produce 1 kWh of power energy, cost associated was Rs 9.00. Maximum diesel replacement in case of rice straw was 47 % while to produce 1 kWh of power energy, cost associated was Rs 10.97. Hence, power generation cost while using biomass is cheaper than conventional power generation cost. 2.4 Energy cost analysis Electricity can be generated using gasifiers either using DG set or using suitably modified natural gas engines/ producer gas engines. The energy cost(Rs/kWh) analysis of two types of mode in generator set are discussed below2.4.1 Dual fuel mode In this the Gasifier is connected to a diesel generator and the generator is suitably modified. In this case up to 70 % diesel replacements are obtained. To generate 1 unit of electricity .08 -0.1 liter of diesel and 0.9 kg of wood or 1.4 kg of rice husk would be needed. Depending on the costs of these (wood chips, rice husk) the fuel cost of generation can be calculated. Savings obtained when a gasifier is coupled to a diesel genset is determined by this calculation. The cost of 1 liter of diesel is Rs 55.15 and assumed the cost of 1 kg of wood or rice husk is Rs 5. One liter of diesel gives 3.5 units of electricity. Thus, fuel cost of generation for 1 unit of electricity (with diesel alone) is around Rs 15.75. For generating a unit of power when the generator set is connected to the gasifier we need .08 -0.1 liter of diesel and 0.9 kg of wood or 1.4 kg of rice husk. If we considered the data (for rice husk) then using equation 2.1 ISBN-978-81-932091-2-7
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Energy cost(Rs/kWh)= (0.1 * 55.15) + (1.4 * 5) Energy cost(Rs/kWh)= 12.515 the fuel cost of generation for 1 unit of electricity is INR 12.515. 2.4.2 100% Producer gas mode Here the Gasifier gets connected to a gas engine generator set(modified). Biomass produced gas(producer gas) is directly given as fuel to generator(no diesel) known as 100% producer gas engine. To generate 1 unit of electricity it required 1.3 kgs of wood or 1.8 kgs of rice husk. Savings obtained when a gasifier is coupled to a gas genset is determined by this calculation, using equation 2.1 Energy cost (Rs/kWh)= (1.3 * 5) + (1.8 * 5) Energy cost(Rs/kWh) = 15.5 The cost of 1 kg of wood or rice husk is assumed around Rs 5. So, the cost of generate 1kWh energy is Rs 15.5. The cost of 1kWh energy of 100% Producer gas is high because of the cost of rice husk and wood is assumed equal to Rs 5. If the cost is less of rice husk and wood the cost of 1 kWh is also less. 2.5
Sustainability of modified gas engine
Where there is no possibility to connect to the grid (e.g. the electric energy supply of households, holiday houses, isolated objectives, equipment in industrial sites, electric installations for outdoor entertainment events, military equipment, telecommunications, etc.), or as emergency regime, as a reserve electric power source, in the event of electric power blackouts. In emergency regime the diesel generator sets usually supply only vital consumers, like re pumps, elevators, safety lighting installations, banks, hospitals, government buildings, offices, mobile towers, supermarkets and large restaurants, hotels, malls, stadiums, airports, fuel stations, private houses, and industrial sites where specific processes do not allow for blackouts, become uncontrollable or generate important losses without electric power, etc. Usually, in parallel with diesel generator sets, UPS systems are used, with a buffer, able to ensure for short periods the continuity of power supply for vital consumers, until the diesel generator sets are started-up. The minimum combined time necessary for the detection of a grid voltage drop, the start-up of internal combustion engine, reaching the stabilized regime of the generator (frequency and
voltage) and the load connection is typically at least in few seconds. In the case of power systems based on renewable energies, given the uctuate character of unconventional energy sources, diesel generator sets takes on particular importance, their role being to ensure the continuity of electric power for the local grid during periods when the renewable sources of energy become unavailable or insufficient. Advantages of this modified gas engine [9] compare to diesel generator isď&#x201A;ˇ Social well being ď&#x201A;ˇ Economic well being ď&#x201A;ˇ Environmental well being ď&#x201A;ˇ Technology well being 3. Diesel Generator Sets Diesel generator sets convert fuel energy (Diesel OR Gas) into mechanical energy by means of an internal combustion engine, and then into electrical energy by means of an electric machine working as generator[1]. The main characteristics of a diesel generator set are : rated power , rated voltage, rated frequency and number of phases, etc. The diesel generator sets are usually designed to run at synchronous speed 3000 rpm or 1500 rpm at a frequency of 50Hz (for two-pole and four pole) and 3600 rpm and 1800 rpm at a frequency of 60 Hz (for two-pole and four pole). Speed regulator and voltage regulator are the two component which help to give proper operation of diesel generator set is determined to a great extent. The performance of these components are vital for the operation and utilization of diesel generator sets, their purpose being to precisely maintain the imposed parameters of electrical power(voltage and frequency). The relation between speed and frequency(f/N) of an ac machine is given by this formulađ?&#x2018;&#x192;â&#x2C6;&#x2014;đ?&#x2018; 120 where f = frequency(Hz), P = number of poles of the generator rotor, N = synchronous speed (rpm) and Figure 3.1 shows the general diagram of diesel generator set. The equation of electrical power of three-phase machine are shows the relation between fuel flowrate and power produced by the generator. đ?&#x2018;&#x201C;=
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figure 3.2
Figure 3.1: General diagram of diesel generator set[4] The equation of three phase electrical power is
given byđ?&#x2018;&#x192; = â&#x2C6;&#x161;3 đ?&#x2018;&#x2030; đ??ź cos ɸ
The generator output power is increased or decreased it is dependent on torque provided by the machine. In mostly cases the voltage of synchronous machine is rated or desired so it is fixed and power factor for resistive load is 1, and if power factor is assumed that it is equal to 1 then only current in ampere required to increase, So stator current is increase while increasing the torque because stator current is directly proportional to torque. Input fuel is also directly related to torque produce by machine it means increase in amount of fuel, also increase torque and it is increased the stator current and produced more power and vice versa. Diesel generator set combined with Prime mover, excitation system and synchronous machine. 3.1 Prime mover The primary movers are internal combustion engines equipped with mechanical regulators or governor to keep the imposed speed, integrated in the injection pump and adjusted to obtain an output frequency of 50 Hz or 60 Hz for rated load. In diesel generator sets, there is speed governor equipped with prime mover. The purpose is ensuring that the diesel engine can be specified speed to stable operation. The combination of diesel engine and governor is used second-order to modelling and their transfer function also shown in
Figure 3.2: Controlled diagram of Prime Mover [4] The speed regulator is basically designed to keep constant speed of internal combustion engine by changing the quantity of fuel consumed by the motor. Actually, frequency is directly proportion to the generator speed so the direct result of this speed regulation is a stable frequency of voltage at the generator terminals. A constant frequency requires good precision and a short response time from the speed regulator. The speed regulator starts regulating when various electric loads are connected or disconnected at the generator terminals. There are a lot of speed regulating systems, starting from simpler spring-based ones up to complex hydraulic and electronic ones able to regulate dynamically the fuel admission valve to keep the speed constant in a given range with response times at load changes smaller than 1-4 seconds. In figure, đ?&#x153;&#x201D; (pu) is reference value of speed equal to 1 and đ?&#x153;&#x201D;(pu)is per unit value of actual speed of synchronous generator, đ?&#x2018;&#x192; (pu)is per unit mechanical output power of diesel engine used to drive generator.Speed of machine is maintain constant for e ciently using generator output power and same actuator tries to adjust the speed of machine. The simulation model of diesel engine governor is shown as figure 3.3
Figure 3.3: Simulation model of diesel engine governor ISBN-978-81-932091-2-7
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The Output speed of diesel engine is going through integral unit conversion for torque. Because diesel engine is a large time delay system, So the torque first go through delay unit then multiplied by the actual speed of machine and such result known as mechanical power. Here in DG set engine inertia is combined with the generator inertia. The torque or mechanical power drives generator and produce electricity and then it feed to different load. 3.2
Synchronous machine
A synchronous machine is a device for converting torque into amperes or it converts the mechanical power into the electrical power. The synchronous machine block operates in both generator and motor modes if torque or mechanical power is positive it works as synchronous generator and if mechanical power is negative it works in a motor mode. The numerical models that can be used in the study of the synchronous generator can be classified into circuit models and field models, with the ones most used in electric drive systems being the circuit models. Before starting the simulation there is required to initialize the machine for starting in steady state region. 3.3
excitation system are used because after transient it will get stable fast so time required very less compair to other excitation system. The modelling diagram of AC1A excitation system with its transfer function is given below in figure 3.4
Excitation system
Excitation system is the important segment to ensure the voltage accuracy of generation and improve the stable operation of power system. Reactive power generation also depend on excitation system it means if increasing the excitation being applied to the generator rotor reactive power will increasing acts as inductive region and also power factor decreasing that time while generator terminal voltage and the local grid voltage increased slightly so result is reactive power began to ow in the generator stator winding and real power decreased. The automatic voltage regulator is to control the voltage at the generator terminals and keep it constant by limiting as fast as possible the voltage peaks and over voltages that occurs due to load variations. The function of excitation control system mainly in the following aspectsď&#x201A;ˇ Maintain generator terminal voltage constant ď&#x201A;ˇ Control reactive power allocation of parallel operation generator ď&#x201A;ˇ Effectively improve system static stability ď&#x201A;ˇ Improve system transient stability In all the cases of diesel generator set AC1A
Figure 3.4: IEEE type AC1A excitation system model 3.4
Problem Identification
3.4.1 Frequency droop control The system is in stable condition if frequency deviation is in range of plus-or-minus 3 %. When system is synchronize with the other system or grid with same frequency and voltage level the frequency is not constant. It always try to maintain frequency about constant but during sudden load increasing or decreasing frequency variation is done. During sudden connection of high load system frequency will decrease as voltage decrease and speed of synchronous generator also decreased. So it will maintain the frequency nearer to base frequency. The problem like blackout were occurs only due to this frequency droop so the control is must require for stable operation of power system. In figure 4.5 shows how to measure the frequency of synchronous generator. 3.4.2
Voltage regulation
In most case the generator terminal voltage having rated or desired value. The range of plus-or-minus 5% are allow to terminal voltage swing but more than that system collapse. The terminal voltage is the magnitude of dqo component of stator voltage V and đ?&#x2018;&#x2030; i.e. đ?&#x2018;&#x2030; = đ?&#x2018;&#x2030; +đ?&#x2018;&#x2030; The generator terminal always maintain at 1 per unit but due to some cases like fault and rapid load change it will decrease or increase so system is in ISBN-978-81-932091-2-7
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unbalance condition. If generator terminal voltage is decrease it means the stator current is increase and vice versa. For stable operation to maintain the generator terminal voltage equal to 1 pu must require. In figure 4.5 also shows the measurement of generator terminal voltage is in Pu or actual value but in mostly cases it is desired.
Figure 3.5: Block diagram of diesel generator set 3.4.3 Rotor speed droop control The term fuel, torque, speed and also frequency are interrelated because speed is directly proportion to frequency (fâ&#x2C6;?N). The real power generation also decreased due to this issue of speed and frequency droop. For stable or reliable operation speed maintain by governor or other regulator function nearer about 1 pu. 3.4.4 Active and reactive power control The active power and reactive power is directly proportional to respectively governor(fuel) and excitation system. Reactive power is increased as excitation increases and real power is increase as input fuel increases with the constant power factor. If reactive power(VAr) increase so power factor is lagging at that time so it behaves as inductive region. Excitation is used to control reactive power in stator terminal of the generator. In figure 4.5 shows the measurement of active and reactive power generate in stator winding of generator. 3.5
Simulation parameter
ď&#x201A;ˇ
Power supply parameters are as follows
Input source rated three phase apparent power : P = 7:54 MW. Rated voltage: đ?&#x2018;&#x2030; = 25KV. Rated frequency= 60 HZ. Use a static load of 5MW to simulate the total power input system. The primary and secondary voltages of transformer are 25 KV-2400 V. Three phase switch set to close in the beginning, when the three-phase ground fault happened in 0.1 seconds, the system detects the failure by the detection system and disconnects the normal power grid at that time three-phase switch are to be off. System operating state is emergency diesel generators running. ď&#x201A;ˇ Emergency diesel generators synchronous generator parameters are as follows: Silent pole rotor type is used in the system, where rated capacity: P =3:125MVA. Rated voltage: đ?&#x2018;&#x2030; = 2400V. Rated frequency: 60 Hz. Xd = 1:56, Xq = 1:06, Xdâ&#x20AC;&#x2122;=0.296, Xd"=0.177,Td"=0.05, Td'= 3.7, stator resistance Rs = 0:816, Inertia coefficient is 1.07 and Pole pairs P=2. ď&#x201A;ˇ Induction motor parameters are as follows : rated capacity P = 1:492MV A(0:8889pu), Rated voltage Ve = 2400V , Rated frequency=60 Hz, Stator resistance Rs = 0:029ohm, Stator inductance Ls = 0:0005H, Rotor resistance Rr'=0.022 ohm, Rotor Inductance Lr'=0.0005 H, Mutual Inductance Lm = 0:0345H, Moment of inertia 63.87 and pole pair P=2. ď&#x201A;ˇ Three static non-dynamic loads are as follows: Load 1 =5 MW, Load 2 = 0.5 MW and load 3 = 0.5 MW.
4 Diesel Generator Set Operating in Standby Mode 5
In the case of important equipment or objectives, electric power consumers are usually grouped into vital consumers and non-vital ones. An electric power security solution for the vital consumers is to back-up their supply by means of a diesel generator set. The installation of the diesel generator set should be done so that during a blackout resulting from a grid fault, it is possible to keep connected only the vital consumers. In the case of wind and/or solar renewable power systems, a black out could occur in the event of insufficient solar or wind power. Diesel generator used mostly for isolated purpose such as in mobile towers, hospitals, petrol pumps, colleges etc. It is fact that diesel generator generate 1 kWh energy is costly than the other alternative sources but availability and fulfil all demand so diesel generator is mostly used in isolated load. In case of ISBN-978-81-932091-2-7
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Biogas or biomass gasifier plants, due to weather atmosphere generation may decreased suddenly so in such situation a three phase grid is connected in system which can be represented by a renewable power system. There are groups of resistive type consumers have the rated powers 5 MW (non-vital consumers) and other two each 0.5 MW and a motor 1.492 MW(vital consumers), and they are supplied from the grid. When a three-phase to ground fault occurs at the grid level ,the normally closed breakers B1 cut the energy supply for the non-vital consumers(5MW) and the vital load is supplied by diesel generator set. The three-phase short- circuit occurs in our case after 1.5 seconds from the simulation start. At time instant 1.6 second breakers open and diesel generator set are operated in emergency region. After 6.1 second of simulation start another single line to ground fault occurs in to the system and after 6.4 second it will be automatically cleared also the breaker B2 open at 6.1 second and auto reclose to 6.4 second Diesel generator operated in emergency region is shown in figure 4.1. Where we can identify the time evolutions of mechanical power, rotor speed and output power in per unit. When the short-circuit or fault occurs after 0.1 seconds from the simulation start, the mechanical power produced by the generator set increase from a small value because there is no load connected before 0.1 seconds to the diesel generator set and stabilizes at the value imposed by the regulation system, The output voltage period of time, after which it comes back very quickly at the rated value. Such a voltage drop can be prevented by means of a properly sized UPS system and it is simulated with the help of simulation package in Matlab.
Figure 4.1: Diesel generator set operated in standby mode 4.1 Simulation results
Figure 4.2: Mechanical Power of DG during standby mode
Figure 4.3: Excitation/ field voltage during DG in standby mode
Figure 4.4: Generator terminal voltage during DG in standby mode ISBN-978-81-932091-2-7
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Figure 4.8: Generator output current under three phase short circuit fault Figure 4.5: Rotor speed of machine during DG in standby mode
Figure 4.9: Generator output current under single phase to ground fault
Figure 4.6: Generator output voltage under three phase short circuit Figure 4.10: Rotor speed of motor during DG in standby mode
Figure 4.7: Generator output voltage under single phase to ground fault
Figure 4.11: Frequency of DG set during DG in ISBN-978-81-932091-2-7
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standby mode
voltage increases about 1.433 pu and it also stabilize with in few seconds also it shows in figure 4.3. The voltage (pu) at the stator of generator terminals also demonstrates a significant decrease for a short time, after which it stabilizes in few seconds due to the action of the voltage regulation system. The drop of stator terminal voltage is shown in figure 5.4. During the transient regime, due to the sudden coupling of the load, the machine rotor speed (pu) decreases abruptly, the rotor speed droop is equal to ((0.97-1)/1 * 100)= -3% but within few second or short period it stabilized at the imposed value as a result of the action of the speed regulating system. The curve of rotor speed deviation shows in figure 4.5.
Figure 4.12: Active and reactive power during DG in standby mode
5. Result discussion The swing equation of machine is also write as
J also
dĎ&#x2030; = T â&#x2C6;&#x2019;T dt
đ?&#x153;&#x201D; đ??˝
đ?&#x2018;&#x2018;đ?&#x153;&#x201D; = đ?&#x2018;&#x2021; â&#x2C6;&#x2019;đ?&#x2018;&#x2021; đ?&#x2018;&#x2018;đ?&#x2018;Ą
So, in stable or steady state operation speed always be constant to maintain the accelerating power. In case if load decreasing the torque start to accelerating and speed and frequency also increasing when load decreased and if load increasing the torque start to decelerating and also speed and frequency also decreasing while load increased. ď&#x201A;ˇ In figure 4.1 Three phase fault occurs at time between 1.5 to 2.0 seconds from the simulation start. At time instant 1.6 second B1 breaker opened it means renewable source is disconnected and vital resistive load connected to synchronous generator. The mechanical power initially developed by the combustion engine is very small because the synchronous generator coupled with the engine is running without load. After suddenly connecting the resistive load, the mechanical power developed by the engine increases rapidly and after few seconds, a new operation stabilized region is reached. In figure 4.2 shows the curve of mechanical power and it is cleared that within few seconds it is stabilised. Excitation voltage initially set at 1 per unit but at the time of sudden connection of resistive and motor load transient region occurs and excitation
ď&#x201A;ˇ In figure 4.6 and 4.8 the waveform of line voltage and line current shows that unbalance occurs due to the three-phase short circuit fault. In line voltage at time 1.5 second (During fault) current ow at low resistance path so voltage drop is reduced to some extant but in case of line current at time 1.5 seconds suddenly increased because load at that time is increased to some extent. The behaviour of line voltage and current are shows that how they increased and decreased during faulty time and then after opening of circuit breaker at time 1.6 second DG start to supplying the load and both are stabilized according their load at that time because after 1.6 second grid is disconnected. ď&#x201A;ˇ In figure 4.7 and 4.9 the waveform of line voltage and line current shows that the effects of single line to ground fault in the system. In line voltage and line current at time 6.1 second fault occurs and at time 6.12 second B2 circuit breaker opened so it disconnects that load. In between the unbalance of line voltage and current are shown in figure they suddenly increased to at some extant and after opening of circuit breaker both stabilized with in few seconds. ď&#x201A;ˇ In figure 4.10 shows that three phase short circuit occurs at time 1.5 second and that time rotor speed decreased and the speed droop is equal to ((1630-1690)/1690 *100)= -8.9%. After opening the circuit breaker B1 means grid is o and DG instantly supply to the vital load (Motor and resistive) and rotor speed of motor back in stabilized limit at 1690 rpm. At time 6.1 second another single line to ground fault occurs and that time also system unbalance and ISBN-978-81-932091-2-7
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at time 6.2 second load being disconnected and the results of rotor speed of motor shown in figure 4.10. In figure 4.11 shows that the frequency curve for Diesel generator set operated in emergency condition. At time 1.5 second fault occurs during this frequency and speed goes down because both are proportion to each other so frequency droop during three phase short circuit fault is equal to((58.25-60)/60*100=-2.1% so it is inacceptable limit and after that 1.6 second it is stabilized back to 60 Hz. At time 6.1 second another single line to ground fault occurs and at time 6.12 second the grid is disconnected and system supply by diesel generator set so during this fault frequency also deviate to some extent and it will stabilized back to 60 Hz. In figure 4.12 shows the generated active and reactive power in output of diesel generated set. DG start after opening of B1 circuit breaker when main grid is disconnected till DG no active power is generate but initially reactive power is generating it shown in figure about 0.3 MW. At time 1.6 DG set generate active power nearer about 0.8 MW and it is stabilized after faulty duration. Another fault come at time 6.1 and at time 6.12 load being disconnected so actual real power decreased to some extent so it is also shown in figure 4.12
6. Conclusion and Future scope Diesel generator set is combination of prime mover, excitation system and generator so speed and voltage are required to maintain to operate system in stable condition. Diesel generator set increases the reliability of the system with renewable sources in case of stand by operation and DG also used as primary source of supply electricity to vital load and it is reliable for continuous supply to vital load. Normally DG rating are small hence they offer better system performance while connected in distributed manner. This is especially suitable in remote areas and villages where power quality and reliability is a matter of concern. Diesel generator are used as backup supply system but Dual fuel type like diesel and gas (syngas) DG engine will impact less on environment and improves reliability of system. Use like bagasse, rice husk, wood chips, cotton
stalks etc different type of fuel to replacement of diesel in DG set so per kWh energy cost also reduced. Involving power electronics system to further improve the performance of the system.
8. References [1] Robert J. Best, D. John Morrow, David J. McGowan and Peter A.Crossley,\Synchronous Islanded Operation of a diesel Generator", IEEE TRANSACTION OF POWER SYSTEM, VOL.22,NO.4,NOVEMBER 2007. [2] S. Krishnamurthy, T.M. Jahns, and R.H. Lasseter,\The Operation of Diesel Gensets in a CERTS Microgrid", inConf. Proceed. of 2008 IEEE Power and Energy Society General Meeting - Conversion and Delivery of Electrical Energy in the 21st Centruy, pp. 1-8, July 2008. [3] Tiberiu Tudorache, Cristian Roman,\The Numerical Modeling of Transient Regimes of Diesel Generator Sets", Acta Polytechnica Hungarica.Vol.7,No.2,2010. [4] Ashish Malik, Lakhwinder Singh and Indraj Singh,\Utilization of biomass as engine fuel",Journal of Scientific and Industrial Research. Vol. 68, October 2009,pp. 887-890. [5] T. Theubou, R. Wamkeue and I. Kamwa. “Dynamic Model of Diesel Generator Set for Hybrid Wind-Diesel Small Grids Applications", IEEE Canadian Conference on Electrical and Computer Engineering(CCECE)2012: Montreal, QC, Canada. [6] Yao lian-fu, Liu Qian, Li Shi and Zhang Zhen-yu. “Simulation and Dynamic Pro-cess Analysis of Nuclear Emergency Diesel Generators". International Conference on Informatics, Cybernetics, and Computer Engineering (ICCE2011) November 1920, 2011, Melbourne, AISC 112,pp 107-115. [7] Aparna Pachori, Payal Suhane.\Design and Modelling of Standalone Hybrid Power System with Matlab/Simulink",International Journal of Scienti c Re-search and Management Studies(IJSRMS), ISSN:2349-3771. [8] Biomass Gasi cation Based Power Generation by Arashi Hi-Tech Bio- Power Private Limited. [9] MNES Annual Report 2002-2003 (Ministry of Non-Conventional Energy Sources, Govt of India, New Delhi.
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Energy Conservation Options to Transport Solids at Higher Concentration Navneet Kumar a,*, Sanjeev Kumar Sharmab, Desh Bandhu Singh a of Mechanical Engineering, Galgotias College of Engineering and Technology, Greater Noida, G.B. Nagar, Uttar Pradeshâ&#x20AC;&#x201C;201308, Email: navneet_mech48@yahoo.com bDepartment of Mechanical Engineering, Amity University, Noida, Uttar Pradesh
aDepartment
Abstract Conveying of granular solids in slurry form through pipeline systems is widely applied in industries due to its several inherent advantages, such as, continuous delivery, flexible routing, ease in automation and long-distance transport capability, etc. The present need of energy and water resources conservation, industrial requirement of transporting a large quantity of solids mass and improved understanding of the flow mechanism of low concentration solids slurry have given an impetus to the emergence of higher solids concentration slurry transport systems which adds a new dimension to the slurry transport arena. The present study aims to generate an extensive experimental dataset from the pilot plant test facility for better understanding the flow pattern in such pipelines. Pressure drop and solids concentration profiles are the most significant technical indicators need to be considered in designing the pipeline slurry transportation system. Therefore, a test loop system is employed to investigate the pressure drop and solids concentration profiles of iron slurry with different mix proportions which had 105 mm diameter pipe to facilitate investigation of the changes in the flow characteristics of commercial slurries and to correlate the efflux concentration and flow velocity with the various design parameters. KEY WORDS: iron ore, higher concentration, rheology. 1. INTRODUCTION As a viable alternative means of a large-scale solids transport through pipelines, a slurry pipeline system is commonly used across the world for conveying of several materials such as coal, fly ash, lime stone, zinc tailings, rock phosphate, gilsonite, copper concentrate, iron ore etc. In such systems, water is usually being used as a carrier fluid. Due to huge power consumption, the method is drawing attention in recent years. Iron ores through the slurry pipelines are currently transported from mines to the processing plants and coming up in large numbers not only in India but also across the world. The high concentration slurry pipeline system has emerged out as a preferred option of solid materials transportation since it deems to be an economical and environment friendly. Further, the present enhanced consciousness towards the imbalance in the eco-system and related stringent government policies are also forcing the industries to adopt environment friendly transportation systems. Studies carried out on solids material transport systems have shown that the slurry conveying at higher concentration reduces the skewness in solids
concentration profile (Kaushal et al., 2005), hence, it necessitates a relatively lower transport velocity as compared to that in low solids concentration transport systems. This way, higher concentration slurry conveying system require less quantity of carrier fluid with likely reduction of pipeline wear, which in turn, will eventually increase the life of pipelines. In order to optimize the performance of slurry pipeline, an experimental database is essential to design an optimal slurry pipeline system. It is, thus, desirable to have the concentration of commercial slurries high, to an extent possible, so as to make the system economical. Published data (Thomas, 1978; Soo, 1987; Slatter and Wasp, 2002) have shown that fine particles slurries at solids concentration above 50% by weight behave like pseudohomogeneous suspensions. Thus, the pipeline can be operated at significantly lower velocities since the critical deposition velocity for such slurries are observed to be very low. Increased solids concentration beyond 50% by weight makes it possible to convey the slurry ISBN-978-81-932091-2-7
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through pipeline in laminar regime since the slurry exhibits non-settling behaviour. Bunn & Chambers (1993) found that such slurries display non-Newtonian characteristics at higher solids concentration. Gopaliya and Kaushal (2016) performed the sand-water slurry flows through horizontal pipeline and highlighted the effect of grain sizes on various slurry flow parameters. Recently, Kumar et al. (2016) performed numerical simulation of horizontal slurry flow (water-glass beads) of coarse particles suspensions in a Newtonian carrier fluid. Glass-beads-water slurry having 440μm mean diameter particles is analyzed through 54.9 mm diameter pipe at efflux concentrations up to 50% flowing with different slurry velocities up to 5 m/s. A significant number of literatures on low concentration slurry transport systems have reasonably explained the transport flow characteristics of solids but the phenomenon is not yet fully understood for conveying of higher concentration slurry owing to complex interactions among the constituent phases. Therefore, the present study delves deep into the transport mechanism of higher concentration slurries by conducting experiment investigations. In order to address these concerns, experimental analysis of 12µm iron-ore slurry flows through 105 mm horizontal pipe having efflux concentration and mixture velocity ranges of 2.63 to 31% (by volume) and 1.35 m/s to 5.11 m/s respectively have been performed during present study. 2. MEASURED MATERIAL AND BENCH SCALE PROPERTIES The physical properties of iron ore are given in Table 1. The measured specific gravity and median particle size d50 of iron ore are 4.35 and 12µm respectively. Table 1 Physical properties of iron ore (a) Specific gravity of iron ore = 4.35 (b) Settling characteristics of the iron ore suspension (Initial concentration Cw = 30% by weight) Time 0 0. 1 5 2 50 80 14 (minu 5 5 40 tes)
Settle 3 32 3 42 6 79 83 83 d 0. .2 5. .3 5. .5 .0 .0 conce 0 0 0 0 0 0 9 9 ntrati on (% by weigh t) Final static settled concentration (Cw)ss = 83.09% by weight or (Cv)ss = 53.04% by volume. 2.1. RHEOLOGICAL SLURRY
TESTING
OF
Slurry rheology is the most important key parameter in the design of slurry pipeline transportation system for the flow of Newtonian and non-Newtonian fluids. The rheological property so obtained was used as input parameter to determine the pressure drop for the estimation of pumping power. The rheological experiments were conducted using RheolabQC (Anton Paar GmbH, Austria). In this study a RheolabQC with measuring cup CC27 and a sensor system ST22-4V-40 having 4-bladed vane geometry was used. The diameter and length of the vane rotor was 22 mm and 40 mm respectively. 2.2. EFFECT CONCENTRATION RHEOLOGY
OF ON
SOLID SLURRY
The rheological data in terms of shear stress (τ) and shear rate (γ), in slurry concentration range for iron ore of 18.69–56.57% (by vol.) has been collected. It is seen that the variation of the shear stress with shear rate at all follow straight line behaviour. The data of rheological characteristics analyzed by adopting the Bingham-plastic model. The rheological characteristics of slurries are strongly affected by the solid concentration in Fig. 1(a-c). With the solid concentration increases, it would become progressively more strongly nonNewtonian fluids, signifying a remarkable ISBN-978-81-932091-2-7
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shear-thinning characteristic over the entire shear rate range. The variation of apparent viscosity versus shear rate with concentration is presented in Fig. 1(d-f). It is observed that the apparent viscosity increased with the increase of solid concentrations and decreased with the increase of shear rate.
(a) (b) (c)
(d) (e)
(f)
Fig.1 Rheological Characteristics of iron ore slurry at different solid concentration 3. EXPERIMENTAL FACILITY Pilot plant test loops are suitable for studying the effect of flow rates, mixture velocity and concentration on flow behaviour, pressure drops and solid concentration profiles is laid horizontally in the Fluid Mechanics Laboratory at I.I.T. Delhi. Each test rig
consists of 50 and 105 mm diameter pipes approximately 60 m long (see Fig. 2). The mixing tank, measuring tank, slurry pumps, two pipe loops of different diameters and by pass line are the major components of pilot plant test loop. The slurry is prepared in a hopper shaped mixing tank. It is made from 4 mm thick mild steel sheets with height of 2 m. On other hand, this tank is also provided with a mixer arrangement by an electric motor mixes the water and the solid particles mechanically. The slurry is pumped from this tank into the 105 mm diameter pipe loop by a centrifugal slurry pump (WILFLEY Model, Ni-hard coupled with 50 HP motor) and flow in the 50 mm diameter pipe loop obtained by means of a rubber lined slurry pump (M/s. International Combustion Ltd.). Both the pumps are having sufficient capacity to cover the entire range of head and discharge needed at all concentrations in both different diameter pipe loops. The flow rate of the slurry in the two pipe loops is maintained over a wide range by AUDCO valves (plug types) provided near the delivery of the pump in each loop. A diverter is also provided at the main exit of the pipe loop which facilitates the diversion of the flow to the concerned measuring tank. The shape of measuring tank is hopper type with height of 1.5 m and total volume capacity (1.25 m3). The magnetic flow meter provided in the vertical section of the pipeline. To ensure the accurate flow rate of slurry, further, a calibrated electro-magnetic flow meter was also installed in the horizontal section of the pipeline for regular monitoring of flow. The slurry volumetric flow rates and velocities were measured using electro-magnetic flow meters. For the visualization of slurry flow to estimate the deposition velocity, a transparent (perspex pipes small length) observation chambers in straight reach of the pipelines were installed in both pipe loops. It gives the idea about deposition velocity to avoid the chocking of the slurry pipeline system. The minimum slurry flow velocity is usually kept more than the deposition velocity. Many pressure taps along with separation chambers ISBN-978-81-932091-2-7
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have been installed at different positions in the straight reach and pipe bends of pilot plant loop. Separation chambers were provided at each pressure tab so that slurry does not enter in manometric tubes or interface separation of the slurry and the manometric fluid (water) as intermediate fluid.
Fig.2 Schematic diagram of pilot plant test loop The pressure drop between any two pressure taps was measured in either of the pipe loops by using differential pressure transducers (with capacity of 100 KPa) and flow rate was controlled in each pipe of pipe loops by plug valves fitted in the individual loops. To ensure the fully developed flow, the pressure taps are provided more than 50D where D is the pipe inner diameter, the gets flow fully developed. To determine the local solid concentration distribution through the pipe cross-section, a sampling tube for drawing out samples is provided in each loop. Concentration distribution in the straight pipe and along the bend tangent length has been measured using a sampling tube having a 4 mm x 6 mm rectangular slot 2 mm above the end to collect representative samples in the pipe line. Samples are collected from different heights from bottom of the pipe in the vertical plane of the cross-section to a sieve analysis to measure the concentration profile at each elevation under near isokinetic conditions. During the collection of samples, it is ensured that the flow of the slurry through the sampling tube outlet is nonstop and uniform. At the end of the
pipe loop a sampling point is also provided in the vertical portions to collect an average efflux sample. The accuracy of the sampling tube is checked by integrating the measured concentration profile to obtain overall concentration and comparing it with the measured efflux concentration. During the collection of concentration samples at various locations, it was ensured that the flow of the slurry through the sampling tube outlet is continuous and uniform. The specific gravity of the slurry flowing through pipeline is determined by collecting samples through a sample point provided in the vertical section. 4. RESULT AND DISCUSSION In the present work, an effort has been made to generate the data for pressure drop and concentration distribution in 105 mm internal diameter of pipelines for the flow of iron ore commercial slurries at higher concentrations. During the pilot plant loop test facilities the settling of the slurry was not observed even at the minimum value of the flow velocity at any efflux concentration of slurry tested. 4.1. PRESSURE DROP Pressure drop for iron ore slurry of 12µm particles are presented in Fig. 3 at seven different efflux concentrations namely 0, 4.91, 7.83, 11.8, 16.6, 23.48 and 31% by volume. It is observed that the pressure drop at any given flow velocity increases with increase in concentration. This trend is seen for all concentrations at all velocities. The rate of increase in pressure drop with concentration is comparatively small at low velocities but it increases quickly at higher velocities, pressure drop is more at higher velocities, due to greater surface area causing extra frictional losses in suspension. 4.2. CONCENTRATION AND DISTRIBUTION
PROFILES
To calculate the energy dissipation in the pipe, knowledge of the concentration and size distribution of solids is also essential. Evidently the local chord concentration can ISBN-978-81-932091-2-7
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V=4 m/s V=5.11 m/s
0.3
y'
0.1 -0.1 -0.3 -0.5 0
0.5
0.5
y'
0.1
-0.3 -0.5 0
0.5
0.5
1 1.5 2 C(y')/C vf
2.5
3
V=1.35 m/s V=2.15 m/s V=4.92 m/s
0.3
y'
0.1 -0.1 -0.3 -0.5 0
0.5
1 1.5 2 C(y')/Cvf
2.5
3
(a) Cvf = 2.63% (b) Cvf = 4.91% (c) Cvf = 7.83% 0.5
V=1.72 m/s V=2.55 m/s V=3.3 m/s V=4.9 m/s
0.3
y'
0.1 -0.1 -0.3 -0.5 0
0.5
0.5
1 1.5 2 C(y')/Cvf
2.5
3
V=1.41 m/s V=1.87 m/s V=2.63 m/s V=3.11 m/s
0.3 0.1 -0.1 -0.3 -0.5 0
0.5
Cvf = 4.91% Cvf = 7.83%
0.5
Cvf = 11.8%
0.3
Cvf = 16.6%
1 1.5 2 C(y')/C vf
2.5
3
V=1.68 m/s V=2.21 m/s V=2.85 m/s
0.1
y'
Pressure Drop (kPa/m)
3
-0.1
Water data
2
2.5
V=1.61 m/s V=2.62 m/s V=3.65 m/s V=5.07 m/s
0.3
3
2.5
1 1.5 2 C(y')/Cvf
y'
show a clearer picture of the distribution of solid particles and their movement in the vertical axis of the pipe cross-section. The distribution of solids across the cross-section depends on various factors, such as flow velocity, the vertical depth of the pipe, the particle size, its density and solids concentration etc. Solid concentration distribution was measured using a traversing mechanism and isokinetic sampling probe at six levels in the vertical plane. Measured vertical Solid concentration distributions are shown in Fig. 4 (a-f) at different flow velocities. Fig. 4 (a-f) shows concentration distributions in the vertical plane for iron ore slurry of 12 µm, by C(y')/Cvf where C(y') is the volumetric concentration at y' = y/D, y being distance from the pipe centre and D the pipe diameter and Cvf, is used average efflux concentration in each experiment. It is observed that the degree of asymmetry in the solids concentration distributions for same concentration of slurry increases with decreasing velocity. From these figures, the skewness keeps reducing with increase in concentration. It is also observed that for a given velocity, increasing concentration reduces the asymmetry in the vertical solid concentration distributions because of enhanced interference effect between solid particles. The effect of this interference is so strong that the asymmetry even at lower velocities is very much reduced at higher concentrations.
Cvf = 23.48%
-0.1
Cvf = 31%
1.5
-0.3 -0.5 0
1
0.5
0.5
(d) Cvf = 11.8% (f) Cvf = 23.48%
0 0
1
2
3 Vm (m/s)
4
5
1 1.5 2 C(y')/C vf
2.5
3
(e) Cvf = 16.6%
6
Fig.3 Measured pressure drop variation with flow velocity at different solids concentration
Fig. 4 Measured solid concentration distributions in a horizontal pipe
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5. CONCLUSIONS Bench scale, rheological properties and pilot plant loop testing were determined experimentally. Pilot plant loop test involving conveying of iron ore slurries through straight horizontal pipeline at various solid concentrations revealed that the pressure drop increases with the increase in slurry concentration for a given flow velocity. It is also found that for all efflux concentrations, the extent of asymmetry in the concentration profile increases with decrease in the flow velocity. This is expected as a reduction in flow velocity there will be a decrease in turbulent energy which is responsible for keeping the solids in suspension. Asymmetry in the concentration profile at any given flow velocity tends to decrease with increasing slurry concentration because of enhanced interference effect between particle- particle. The cause of this interference is so strong that the asymmetry even at lower velocities is very much reduced at higher concentrations.
2.
3.
4.
5.
6. 7.
REFERENCES 1. Bunn, T.F., Chambers, A.J., (1993). Experiences with dense phase hydraulic conveying of vales point fly ash. Powder Handling and Processing, 5, 35-43.
Gopaliya, M. K., Kaushal, D. R., 2016. Modeling of sand-water slurry flow through horizontal pipe using CFD. Journal of Hydrology and Hydromechanics. 64 (3), 261–272. Kaushal, D.R., Sato K., Toyota T., Funatsu K., Tomita Y., 2005. Effect of particle size distribution on pressure drop and concentration profile in pipeline flow of highly concentrated slurry. International Journal of Multiphase Flow, 31, 809-823. Kumar, N., Gopaliya, M. K., Kaushal, D. R., 2016. Modeling for slurry pipeline flow having coarse particles. Multiphase Science and Technology, 28 (1): 1-33. Slatter, P. T., Wasp, E. J., 2002. The Bingham plastic rheological model: friend or foe? Proc. Hydrotransport 15, BHR Group, Cranfield, Bedford, England, pp. 315-343. Soo, S. L., 1987. Pipe flow of dense suspensions. Journal of Pipelines, Vol. 6, pp. 193-203. Thomas, A. D., 1978. Coarse particles in a heavy medium-turbulent pressure drop reduction and deposition under laminar flow. Proc. Hydrotransport 5, BHRA, Hannover, Germany, paper D5.
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Analysis of Process Characteristics for a Batch Production Unit and Controlling the Variation for Effective Performances Navneet Kumar a,*, Sanjeev Kumar Sharmab, Krishna Mohan Agrawalb aDepartment of Mechanical Engineering, Galgotias College of Engineering and Technology, Greater Noida, G.B. Nagar, Uttar Pradeshâ&#x20AC;&#x201C;201308, Email: navneet_mech48@yahoo.com bDepartment of Mechanical Engineering, Amity University, Noida, Uttar Pradesh Abstract Even after such advancement and evolution in the field of manufacturing unit, it is still lacking in delivery quality product as per customer requirement and this can be due to rigidity to change, uncertainties in the system and fluctuation in the desired value. Process is a pre-defined work in which the raw material is converting into a finished goods. Due to variation in the process input parameters, there is an effect on the output product which reduce its effectiveness and reliability. Therefore, it is very important to reduce or control the variation in the process characteristic to sustain the product in a such demanded market. The research is done to analyze each process of a capacitor manufacturing unit using Process flow chart, Failure Mode Effect Analysis and Process control plan to identify the various processes that are at risk, its effect on the output product and developing a control plan for an effective performance and maintaining the quality of work. Keywords: Process Flow Chart, Failure Mode Effect Analysis, Process Control Plan, Risk Priority Number. Introduction in the market. The aim of the research is to With wide range of applications, capacitor is analyze each process characteristics of capacitor coupled in many electronic equipment from manufacturing which is to identify the risk, small to large also called as power capacitor. The effect on the output product and developing a main aim of capacitor is to have standard control plan for reducing and controlling the capacitance value with which it can bear the high effect of variation of process parameters on the current and voltage frequency in the any final product. Hence, Control Plan is a method electrical equipment. Different processes play for documenting the functional elements of significant contribution in the production of quality control that are to be implemented in capacitors like winding, baking, spraying, order to assure that quality standards are met for welding and each process have individual a particular product or service. It can be utilized importance for acquiring a quality capacitor. for maintaining the working conditions and also Most of the manufacturers are implementing a scope for more improvements in the near various technologies to get the best quality future. Furthermore, a Quality Control Plan is a capacitor which leads to a high investment. critically important document for any Various regulations have to be considered while manufacturing unit. It is a description of the manufacturing capacitor as a safety for activities, tools and procedures, needed environment, spraying and coating is a valueto control process that delivers a service or added process which use zinc, zinc-tin and product. Finally, the overall objective is to powder for which the remaining waste goes to minimize and control variation that will be environment. Manufacturing a good capacitor is beneficial for the enhancement of the product. not that much important rather manufacturing it Literature review with healthy environment. Nowadays, Detailed study has been done on FMEA with continuous improvement tool is getting popular RPN to identify the risk or variation in the in many manufacturing units to analyze their process and its effect on the product but working conditions and to sustain their product integrated control plan study is rarely found for ISBN-978-81-932091-2-7
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a process industry. In 1990, B. G. Dale and P. Shaw did a questionnaire survey on the use of failure mode and effects analysis (FMEA) in the United Kingdom motor industry from 78 organization in which they concluded that in many organization are seeking to make more use of this technique to facilitate their process of quality improvement. In 1991, Bejamin C.Wei present a unified approach in performing FMECA applicable to a large plant design and has establish the steps necessary to perform a failure mode, effects and criticality analysis on any item at any level. Later in 1992 warren Gilchrist proposed that FMEA is a major tool for quality improvement, it seeks to prevent faults in product and processes at the design stage and it provides a structured approach to analysis. Later in 1995, Sheng-Hsien(Gray) Teng proposed that Failure mode effect analysis as an integrated approach for product design and process control. The aim of performing FMEA is to develop an effective quality control system, to improve the current production processes, and to ensure high quality and reliability of the products. The integration of FMEA process to product design and process control is absolutely critical to the success of FMEA. In 1998, S. A. Abbasi and Faisal I. Khan did a review on the risk analysis in a chemical process industry in which they address FMEA as technique for identify the failures and its effect. In 2006, Daniel Le Saux implemented the process control plans and FMEA in a semiconductor manufacturing environment in which they concluded that various significant improvement can be achieved in a controlled, proactive manner when process control plans and a dynamic FMEA are developed and maintained. Later in the same year J.Maiti did research on risk and proposed an effective use of resource can be achieved by using risk based maintenance decision to guide where and when to perform maintenance. According to Automotive Industry Action Group(AIAG), Process control are an automotive and aerospace quality tool and considered an output of the Advance Product
Quality Planning (APQP) process. In 2009, Benjamin Kemper did the modelling of process flow using various symbols and diagram and address that process diagram, originally used as a design tool in information technology, nowdays visualize process flow document process performance which display relevant process with process characteristics. In 2010, S.Q.(shane) Xie et al. explains that the process flow chart/diagram is able to effectively represent the type of process knowledge that carriers flow information and generates a visual view of each process of the system. Subsequently in 2104, T.sahoo et al did the implementation of FMEA approach which shows its contribution in reducing the maintenance cost, indeed it defines the requirements of dependability in precise manner. It also identifies critical functions for the system and several maintenance policies for the system and its components. More recent in 2015, N Rachieru et all did the risk analysis of a CNC lathe using FMEA to deal with the risk factors and identify the most serious failure modes for corrective actions. Most of the research is done using FMEA with RPN for process variation/risk assessment but, I have applied an integrated framework as shown in fig 1 as PFD, PFMEA and PCP to each components of a capacitor manufacturing unit to determine the critical process and its risk in the near future and has developed a control plan. Process Process Flow Chart Process
Process Control Plan Corrective Work
Fig .1 Integrated Framework ISBN-978-81-932091-2-7
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Case study This capacitor manufacturing unit is renowned for delivering the effective and safest capacitor in such high competition market to its customer. To continue their quality and substantiality in the market, they are approaching continuous improvement with Advance Product Quality Planning process in their manufacturing unit of capacitor. So, an in-depth analysis on process and product characteristics is performed to identify the failure cause and its effect on the output product and finally control factors are obtained. Methodology Process flow chart A process flow chat (PFC) is defined as a formal graphic representation of a process sequence, work or manufacturing process, organization structure (Lakin et al., 1996). It represents symbols which are used to represent each operation, data, flow direction, equipment etc. (Aguilar -saven 2003). The flow chart consists of product and process characteristics with standard specification of each process parameters. It is used as the initial chart for analyzing the variation in the product and process quality. Various symbols used in process flow chart are shown in the table no. 1 and process flow chart/diagram of current research work is also shown in table no.2 Table no. 1 Symb ols Descr iption
2 Oper ation
Inspe ction
Transp ortation
Opera tion &Insp ection
De lay
Stor age
Deci sion Mak ing
Process Failure Mode Effect Analysis Failure Mode Effect Analysis (FMEA) is a systematic method of seeking out the potential
causes of failure before they become a reality. Hence, it becomes mandatory to be applied during the development stage of product service (warren Gilchrist 1992). The first step in FMEA is to identify all the possible failure modes of the product and system, then the potential effect of the failure modes on the product and process with the cause of the failure mode. Critical analysis is performed on the identified failure modes by taking the following risk factors 1Occurrence (Probability of failure) 2Severity (Severity of the failure) 3Detection (Probability of the nondetecting the failure) The ranking of failure mode for critical actions is determined in terms of risk priority number (RPN) (N Rachieru et al.,2015), where RPN is the product of O*S*D. After the evaluation of RPN of each process, ranking is done in decreasing order to get the maximum RPN process. FMEA uses a scale from 1 to 10 for evaluating the risk factors as shown in table no.3 and table no.4 shown the FMEA of capacitor manufacturing system. Process Control Plan A process control plan (PCP) is a summary of the methods and systems used to control parts and processes according to customer requirements. It addresses product and process characteristics and requirements for control also aims at minimizing the variations. The entire control strategy for a system, subsystem, component or a part is summarized (Daniel Le Saux 2006). It is the final stage in which analysis of PFD and PFMEA data is done for controlling the variation of each process of a system or subsystem and also determines the methods and measurements for controlling the variation when and by whom. Following are the main factors in process control plan/chart and for the capacitor production unit, it is shown in table no.5 1- Process and product attributes: important characteristics or variables ISBN-978-81-932091-2-7
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2- Machine, Tool or Device: equipment used to perform the task 3- Control Characteristics: process parameters being controlled 4- Method: procedure/medium required to control the current process parameters 5- Frequency: how often the process control take place
6- Reaction plan: activity that will take place if the process control fails Classification: quality, safety and regulations as per norms
Table no.2 Operation sequences
Operation description
Incoming source of variation
Significant product characteristics (output)
Significant process characteristics (input)
comments or notes
Winding
Winding of the inner and outer film to wrap on mandrill
Maintenance and tool
Film capacitor with length and width, wave cut and diameter
Main film turn, pressure roller tension, stagger, burn off foil
No quick action on breakdown
Pressing
To remove holes and gap between films of capacitor Capacitors masked in different rolls Spraying of zinc and zinc-tin on roll through gun
Cold pressing
Pressed capacitor to make strong bond
Maintenance, winding, equipment Masking, winding, machine parameters Operator variation, masking and spraying Spraying
Capacitor rolled in bulk for spray operation Material deposited on side edge of each capacitor
Temperature, pressure, counting, time, jig, pads Roll diameter, ohms design and tape Pressure, deposition area, wire feeding speed, voltage Hand process either manually or automatic
More number of bins for flow Poor material handling Less resource and recycle the waste Variation in time due to odd/bad masking Waiting due to less material High changeover time Excessive and poor material handling Waiting due to material variation
2
Masking Spraying
Demasking
Short clearance, welding
To demask the masked capacitors in units Smoothen the side edges of capacitor To remove errors and defects Rectification of gap and welding of lead on side
Pre-heating, wax, paint coating
Heating and protection from the atmosphere
Operator variation and material
Marking
Labelling of specification and lot number Heating of capacitor Naked eye inspection To disjoint units from rod
Operator and maintenance
Deburring Baking
Post Curring Visual Inspection Disjoint
Environment Spraying and operator variation
None Operator None
Unrolled capacitor for the further operations Removal of excessive spray material Heated capacitor to remove errors and defects lead terminal on side edge of capacitor and tapping on rod Coated capacitor to withstand the ambient conditions Indication of value for specific function Defect and error proof Acceptance or rejection Disjointed units
Time and speed (RPM) Temperature and time A.C/D.C voltage, length, pressure, weld area and pitch Time, temperature, vacuum, coat thickness Marking code, machine speed and lot number Time and temperature Undip, joint, bubble, welding Machine speed
Delay due to break down None Less no. of observation None
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Effectiveness of each unit
Powder coating, VI
Reliable capacitor to function
Lead cut form
Cutting in length and shape
Visual inspection
Final inspection Packaging
Final quality check Packing of units in box to customers
Material
capacitor in different cut form on demand Acceptance high rejection high Capacitors in box or packet to delivery
None
Table No.3 Linguist ic terms
Scale/Ra nk
Very low
1/2
Low
3/4
Relatively few
Moderat e High
5/6
Occasiona l Repeated
Very high
9/10
7/8
Occurren ce of Failures Unlikely
Unavoida ble
Severity
Detecti on
Minimal interferen ce Significa nt degradati on Minor damage Equipme nt damage Destructi ve failure
Easily Moderat e Hidden Difficult Very difficult
Conclusion Failures are part of system in any manufacturing unit which affect the sustainability of their product, which cannot be fully eliminated from the system but can be minimized or controlled so that it has less effect on product characteristics. The present work is an analysis of process characteristics of capacitor manufacturing industry for determining the failures occurring in the system and its effect on the output product using PFC, FMEA and PCP. The FMEA chart with RPN identifies that spraying is the most risk bearing process followed by winding and welding which caters for careful investigation for these components in all the areas. A quality process plan is also developed to reduce or control the process variation. These results will be help to increase the effectiveness and quality of the output capacitor with balanced working environment.
H.V, I.R testing, S.C VDC/AC, CAP.value@1khz Lead cutting length, pitch, burr/scratch Defects, AQL, RE, Dimensions Packing type, customer name, piece/polybag
Rework None Poor handling None
References 1. Dale, B. G., & Shaw, P. (1990). Failure mode and effects analysis in the UK motor industry: A state‐ of‐the‐art study. Quality and Reliability Engineering International, 6(3), 179-188. 2. Kemper, B., de Mast, J., & Mandjes, M. (2010). Modeling process flow using diagrams. Quality and Reliability Engineering International, 26(4), 341-349. 3. Warren Gilchrist, (1993),"Modelling Failure Modes and Effects Analysis", International Journal of Quality & Reliability Management, Vol. 10 Iss: 5 pp. 16-23. 4. Teng, S. H., & Ho, S. Y. (1996). Failure mode and effects analysis: an integrated approach for product design and process control. International journal of quality & reliability management, 13(5), 8-26. 5. Khan, F. I., & Abbasi, S. A. (1998). Techniques and methodologies for risk analysis in chemical process industries. Journal of loss Prevention in the Process Industries, 11(4), 261-277. 6. Le Saux, D. (2006). The Effective Use of Process Control Plans and Process Failure Mode Effects Analysis in a GaAs Semiconductor Manufacturing Environment. In 2006 GaAs Mantech Conference ACRONYMS AOI: Automated Optical Inspection HVI: Human Visual Inspection. 7. Arunraj, N. S., & Maiti, J. (2007). Risk-based maintenance—Techniques and applications. Journal of hazardous materials, 142(3), 653-661. 8. AIAG, Advanced Product Quality Planning and Control Plan, (2001). 9. Wei, B. C. (1991, January). A unified approach to failure mode, effects and criticality analysis (FMECA). In Reliability and Maintainability ISBN-978-81-932091-2-7
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Symposium, 1991. Proceedings., Annual (pp. 260-271). IEEE. 10. Chen, W. L., Xie, S. S., Zeng, F. F., & Li, B. M. (2011). A new process knowledge representation approach using parameter flow chart. Computers in industry, 62(1), 9-22. 11. Sahoo, T., Sarkar, P. K., & Sarkar, A. K. (2014). Maintenance optimization for critical equipments in process industries based on FMECA Method. Int J Eng Innov Technol, 3(10). 12. Rachieru, N., Belu, N., & Anghel, D. C. (2015). An improved method for risk evaluation in failure modes and effects analysis of CNC lathe. In IOP Conference Series: Materials Science and
Engineering (Vol. 95, No. 1, p. 012139). IOP Publishing. 13. Aguilar-Saven, R. S. (2004). Business process modelling: Review and framework. International Journal of production economics, 90(2), 129149. 14. Lakin, Richard, Nick Capon, and Neil Botten. "BPR enabling software for the financial services industry." Management services 40.3 (1996): 1820.
Table no.4 Operation sequences
Process function
Product characteristics
Potential failure mode
Potential effect of failure
Potential cause of failure
O
S
D
RPN
Ranking
Winding
Winding of the inner and outer film to wrap on mandrill
Film capacitor with length and width, wave cut and diameter
Oversize
Capacitance decreases
3
9
2
54
2
Undersize
No functioning
Positive value of stagger Negative stagger
2
8
2
32
5
To remove holes and gap between films of capacitor Capacitors masked in different rolls
Pressed capacitor to make strong bond
None
None
0
0
0
0
Machine design and operator effort Insufficient air pressure and current
2
2
28
6
Material deposited on side edge of each capacitor
3
7
3
63
1
To demask the masked capacitors in units
Unrolled capacitor for the further operations
Excessive work
Excessive material in gap leads wastage 100% Deposition is not achieved More effort and loss of deposited material
7
Spraying of zinc and zinc-tin on roll through gun
Gap in between ohm masking Inaccurate Deposition
5
2
2
20
8
Deburring
Smoothen the side edges of capacitor
Removal of excessive spray material
None
None
None
0
0
0
0
Baking
To remove errors and defects
Heated capacitor to remove errors and defects
Temp variation
Due to machine unit
2
8
1
16
10
Short clearance, welding
Rectification of gap and welding of lead on side
lead terminal on side edge of capacitor and tapping on rod
Welding variation
Weaken the bond between films No standard pitch between terminals
Current and less pressure
3
8
2
48
3
Preheating, wax, paint coating
Heating and protection from the atmosphere
Coated capacitor to withstand the ambient conditions
Undip and temperature variation
5
4
40
4
Labelling of lot and number specification
Indication of value for specific function
Missing of labels
4
2
2
16
10
Removal of moisture
Defect and error proof
None
Due to sudden current cut off Machine design and operator skills None
2
Marking
Partial coating and less protective No indication of specification of capacitor None
0
0
0
0
Pressing Masking
Spraying
Demasking
Post Curing
Capacitor rolled in bulk for spray operation
None
Due to masking process and design
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Naked eye inspection
Acceptance or rejection
Disjoint
To disjoint units from rod
Disjointed units
None
Testing
Effectiveness of each capacitor
Reliability of capacitor to function
Cutting in length and shape
capacitor in different cut form on demand
Lead cut form
Final inspection
Final quality check
Quality effectiveness of capacitor
Packaging
Packing of units in box to customers
Capacitors in box or packet to delivery
Operator performance
Acceptance of rejected capacitors None
Acceptance sampling and skills None
Untested capacitor
Less effectiveness of capacitor
Burr formation on lead
No functioning of capacitor
Hold and reprocessing
If rejected full lot becomes scrap
Testing unit in machine design Excessive powder material and cutter in machine Incoming material and acceptance sampling
None
None
None
2
3
3
18
9
0
0
0
0
2
4
3
24
7
1
8
5
40
4
3
2
3
18
9
0
0
0
0
7Table no.5 Elements
Machine/ tools
Product attributes
Process attributes
Winding
Stagger
Insulation Resistance, length and width
Number of turns in stagger
Q
Masking
Rollers and tapes Electric arc gun
None
Machine design Spray gun air pressure
none
Spraying
Demask Baking Short Clearance, welding Preheating and Coating Marking
Visual Inspection
Manually, automatic device Oven machine
Zinc and zinctin deposition None Current leakage
Standard time and environment
Class
S&R
S S&Q
None
Automatic welding, lead wire, rods and tapes Powder and tissue pads Marking powder
Terminals polarity and strong bond
Current and pressure variation
Q
Powder deposition
Current variation
S&R
Labels and code number
Machine design
Q&S
Measuring gauge and tools
Quality
Sampling and observation
Q
Specification tolerance
Evaluation technique
Sample Freq
Control method
Reaction plan
Stagger and number of turns for tension
Micrometer, I.R measuring device and Vernier scale
2/lot
Meet job setter of that process
Gap between each capacitor Gun pressure and current
Visual inspection Pressure Gauge, D Amp/Volt meter Visual inspection
1/roll
Statistical quality control/ Inspection sheet Manually operated Fine surface of side edges
Incoming material and dust Bake time and temperature
1/roll 5-10 /roll
Timer and thermocouple
1/lot
Welding joint and pitch of capacitor
Micrometer and testing device
5-10 /lot
Sudden current shut off Missing of labels and code
Maintenance, inspection
1/lot
Operator performance
Visual inspection, measuring gauge
Visual inspection and skills
1/unit
1/unit
Good masking and mask Productio n Book
Stop the machine Stop the machine and inform incharge Contact supervisor Stop machine
Visual inspection /machine maintenan ce Regular current supply Maintenan ce of machine
Meet line supervisor
Operator skills and Ability
Double inspection by skill operator
Stop the machine Report to Maintenanc e section
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Testing machine
Effectiveness, I.R and delta
Testing and measuring unit
Q
Measuring of parameter
Visual and inspection sheet
1/lot
Lead cut form
Cutter and gauge
Terminal shape or size
Cutting tool
Q
Uncut or burr on capacitor
Cutter and micrometer
1/lot
Final inspection
Inspection devices and gauges
Electrical paraments
Q
Hold, reprocessing or rejection
Acceptance and rejection Sampling
1/lot
None
Check the device and rework Visual inspection Visual inspection and measuring gauge
Stop the machine and inform incharge Check cutter and rework Recheck or meet supervisor
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Availability Analysis of Energy of Micro Hydro Power Plant with Screw Archimedean Turbine in Indian Context. Umanand Kumar, K.S.Chandel Department of Mechanical Engineering, Dr. APJ Abdul Kalam UIT-RGPV, Jhabua, Madhya Pradesh, INDIA. * Corresponding Author’s Email ID: umanand.singh4@gmail.com ABSTRACT The ability of renewable resources is to provide all of society's energy needs as soul for body. The utilization of distributed energy resources is increasingly being pursued as an alternative to large conventional central power stations. Discussions about common and future trends in renewable energy systems based on reliability and maturity of each technology are presented. Micro-hydro power plant based on Archimedes Screws turbine is a type of renewable energy power plant that is environment friendly, easy to be functioned and low operation cost, etc. Turbine for the power plant is mixed flow Archimedean turbine. However, several previous studies have not considered key complexities such as dissimilarities in flows or turbine efficiency. Correspondingly, precise costing and return on speculation data are often absent or deficient sensitivity analysis. Further research is essential to report the risks and long-term reliability of installations, accompanied by the development of firm policy to direct and incentivize sustainability gains in this area. A feasibility study has been carried ready for a micro hydroelectric installation in India. Keywords: micro-hydro power plant based on Archimedes Screw turbine. 1. Introduction: Small scale hydropower constitutes a cost Micro hydropower is an eco-friendly, fish effective technology for rural areas in developing friendly, non-polluting renewable source of countries and, on the other hand, is a quiet energy. It is the oldest renewable energy method growing sector in India. [3] In the last decade, for production of electricity known to mankind problems related to energy crisis such as oil mechanically. According to Kyoto protocol of crisis, climatic change, electrical demand and 1997, most of industrialized countries agreed to restrictions of whole sale markets have a risen set some emission reduction target in order to world-wide. These difficulties are continuously maintain environmental & climatic equilibrium increasing, which suggest the need of of the world exposed by greenhouse effect, ozone technological alternatives to assure their depletion etc. To overcome these problems, solution. One of these technological alternatives renewable energy can be utilized to meet those is generating electricity as near as possible of the international targets. In current scenario, India is consumption site, using the renewable energy blessed with half a million locations where water sources, that do not cause environmental mills are serving for centuries. [2] If micro hydro pollutions, such as wind, solar, tidal and micro power plants are installed there, an energy hydro-electric power plants. [4] equivalent of 15000MW can be generated & 20 million Indians may get employed. There are 1.1 History of screw turbine: nearly 5lac (approx.) potential sites over the The screw turbine is a water turbine which entire Himalayan region from Jammu & Kashmir uses the principle of the Archimedean screw to to north eastern states and can generate power as convert the potential energy of water on an much as of 25000 MW i.e. each can generate at upstream level into kinetic energy. It may be least 5KW. Till date only 25% (approx.) of the compared to the water wheel, though the screw total hydro power potential has been tapped to turbine has a much higher efficiency. generate power. Water mills are enough to run The invention of the water screw is credited TV, refrigerator, cooler, fan & light bulbs etc. to the Greek polymath Archimedes of Syracuse ISBN-978-81-932091-2-7
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in the 3rd century BC. A cuneiform inscription of the Assyrian king Sennacherib (704 - 681BC) has been interpreted by Dalley to describe the casting of water screws in bronze some 350 years earlier [8]. This is consistent with the classical author Strabo who describes the Hanging Gardens as watered by screws. A contrary view is expressed by Dalley and Oleson in an earlier review. The German engineer Konrad Kyeser, in his Bellifortis (1405), equips the Archimedes' screw with a crank mechanism. The Archimedean screw is an ancient invention; attributed to Archimedes of Syracuse (287–212 BC.), and commonly used to raise water from a watercourse for irrigation purposes. [5] In 1819 the French engineer Claude Louis Marie Henri Navier (1785–1836) suggested using the Archimedean screw as a type of water wheel. In 1922 William Moerscher patented the hydrodynamic screw turbine in America. [6] 1.2 History of Micro Hydro Power Plant: The first hydroelectric scheme was installed in Wisconsin in 1882; three years after Thomas Edison invented the light bulb. Soon after, hydropower became an important resource for electricity generation. 20% of total electricity consumed worldwide comes from hydro electrical plants. In some countries hydropower supplies 80% of electricity. This has generally been supplied by larger hydroelectric schemes. Interest in small hydro declined from its historical roots due to the success of these large hydropower plants in bringing down costs and the success of other technologies such as nuclear and diesel generation. However concern about climate change, air quality and nuclear generation and increasing costs of fossil fuel based generation has renewed interest in small hydro and other renewable forms of generation. [7] The use of falling water as a source of energy is known for a long time. In the ancient times waterwheels were used already, but only at the beginning of the nineteenth century with the invention of the hydro turbine the use of hydropower got a new impulse. Small-scale hydropower was the most common way of
electricity generating in the early 20th century. In 1924 for example in Switzerland nearly 7000 small scale hydropower stations were in use. The improvement of distribution possibilities of electricity by means of high voltage transmission lines caused fainted interest in small scale hydropower. Renewed interest in the technology of small scale hydropower started in China. Estimates say that between 1970 and 1985 nearly 76,000 small scale hydro stations have been built there. [8] In 1995, the micro-hydro capacity in the world was estimated at 28 GW, supplying about 115 TWh of electricity. About 60% of this capacity was in the developed world, with 40% in developing areas. Micro hydro plants that are found in the developing world are mostly in mountainous regions for instance in the some places in the Himalayas as well as in Nepal where there are around 2,000 schemes, including both mechanical and electrical power generation. In South America, there are micro-hydro programs in the countries along the Andes, such as Peru and Bolivia. Smaller programs have also been set up in the hilly areas of Sri Lanka, Philippines and some parts of China [9] 1.3 Working of screw turbine based plant: The screw turbine is a water turbine which uses the principle of the Archimedean screw to convert the potential energy of water on an upstream level into kinetic energy. It may be compared to the water wheel, though the screw turbine has a much higher efficiency. The turbine consists of a rotor in the shape of an Archimedean screw which rotates in a semicircular trough. Water flows into the turbine and its weights presses down onto the blades of the turbine, which in turn forces the turbine to turn. Water flows freely off the end of the turbine into the river. The upper end of the screw is connected to a generator through a gearbox. [5] The Archimedean screw turbine is applied on rivers with a relatively low head (from 1 m to 10 m) and on low flows (up to around 10 m3/s on one turbine). Due to the construction and slow movement of the blades of the turbine, the ISBN-978-81-932091-2-7
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turbine is considered to be friendly to aquatic wildlife. It is often labelled as "fish friendly". The Archimedean turbine may be used in situations where there is a stipulation for the preservation and care of the environment and wildlife. [5] The low rotational speed and large flow-passage dimensions of Archimedean screws also allow fish to pass downstream through the screw in relative safety. Archimedean screws are often touted as ‘fish friendly’ hydro turbines, which they undoubtedly are, though we at Renewable First would say that all hydro systems should be fish friendly, regardless of turbine type. In nonscrew hydro systems this just means well designed intake screens and fish passes / by passes would be required. Note that if upstream fish passage is required at an Archimedean screw site, a fish pass will be required. The final advantage of the Archimedean screw is simplified civil engineering works and foundations. Because screws don’t have draft tubes or discharge sumps, it means that the depth of any concrete works on the downstream-side of the screw is relatively shallow, which reduces construction costs. The civils works are also relatively simple, the main part being the loadbearing foundations underneath the upper and lower bearings. In softer ground conditions the load-bearing foundations can be piled. [6] 2. Analysis of Energy: [1] The utility electricity sector in India has one National Grid with an installed capacity of 330.86 GW as on 30 November 2017. Renewable power plants constituted 31.7% of total installed capacity. India is the world's third largest producer and fourth largest consumer of electricity. Electric energy consumption in agriculture was recorded highest (17.89%) in 2015-16 among all countries. India has surplus power generation capacity but lacks adequate infrastructure for supplying electricity to all needy people. In order to address the lack of adequate electricity supply to all the people in the country by March 2019, the Government of India launched a scheme called "Power for
All". This scheme will ensure continuous and uninterrupted electricity supply to all households, industries and commercial establishments by creating and improving necessary infrastructure. Its a joint collaboration of the Government of India with states to share funding and create overall economic growth. 2.1 Power Generation in India:S. No .
Type of Power Generation
Power Capacity(MW)
1. 2.
Thermal Energy Hyd Large ro Small Ene rgy Wind Energy Solar Energy Biomass Energy Nuclear Energy Gas Power Diesel Power Total
1,92,971.5 44963.42 4389.55
Perc enta ge (%) 58.3 13.6 1.3
32700.64 14771.69 8295.78 6780 25150.38 837.63
9.9 4.5 2.5 2 7.6 0.3
3. 4. 5. 6. 7. 8.
330860.51
Power Generation in India(%) Thermal Hydro Wind Solar Biomass Nuclear
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250000 200000
Power Capacity in India(MW) Power Capacity in India(MW)
150000 100000 50000
29.
A&N Islands Total
7.91
5.250
-------
19749.44
3803.678
895.40
Classification of small hydro power projects in India Class Station capacity in KW Micro hydro Upto 100 Mini hydro 101 to 2000 Small hydro 2001 to 25000 2.2.1 Small hydel power condition in India:
A&N Islands
0
West Bengal Uttarakhand Uttar… Tripura
Fig.-1 Describe the comparison of available power with respect to small hydro power (only 1.3%) Contributed. 2.2 Potential, Installed & under Implementation of Small Hydro Power (as on31.03.2014):-[4] State Wise Numbers And Aggregate Capacity Of SHP Projects(Upto 25 MW) S.No. State Potential Installed Implementation(MW) (MW) (MW) 1. Andhra 978.40 221.030 32.04 Pradesh 2. Arunachal 1341.38 103.905 22.23 Pradesh 3. Assam 238.69 34.110 12.00 4. Bihar 223.05 70.700 17.70 5. Chhattisgarh 1107.15 52.000 115.25 6. Goa 6.50 0.050 -------7. Gujarat 201.97 15.600 -------8. Haryana 110.05 70.100 3.35 9. Himachal 2397.91 638.905 76.20 Pradesh 10. Jammu & 1430.67 147.530 17.65 Kashmir 11. Jharkhand 208.95 4.050 34.85 12. Karnataka 4141.12 1031.658 173.09 13. Kerala 704.10 158.420 52.75 14. Madhya 820.44 86.160 4.90 Pradesh 15. Maharashtra 794.33 327.425 43.70 16. Manipur 109.13 5.450 2.75 17. Meghalaya 230.05 31.030 1.70 18. Mizoram 168.90 36.470 0.50 19. Nagaland 196.98 29.670 3.20 20. Orissa 295.47 64.625 3.60 21. Punjab 441.38 156.200 19.45 22. Rajasthan 57.17 23.850 ------23. Sikkim 266.64 52.110 0.20 24. Tamil Nadu 659.51 123.050 ------25. Tripura 46.86 16.010 ------26. Uttar 460.75 25.100 ------Pradesh 27. Uttarakhand 1707.87 174.820 174.04 8. West Bengal 396.11 98.400 84.25
Tamil Nadu Sikkim Rajasthan Punjab Orissa
Potential(MW )
Nagaland Mizoram
Implementati on(MW)
Meghalaya Manipur Maharashtra Madhya… Kerala Karnataka Jharkhand Jammu &… Himachal… Haryana Gujarat Goa Chhattisgarh Bihar Assam Arunachal… Andhra… 0
1000
2000
3000
4000
5000
Fig.-2 Comments
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Describes the comparison of available potential, projects installed & projects under implementation of small hydro power plants in various states of India. Haryana ranked 1st with 63.69 % followed by Rajasthan 41.71% and Goa & Jharkhand ranked last with 0.77% and 1.94% respectively as compared to projects installed & potential available. West Bengal ranked 1st with 28.30% followed by Jharkhand with 17% & Sikkim ranked last with 0.093% followed by Madhya Pradesh with 0.66% as compared to project under implementation and rest of available potential. 2.3 Established screw turbine power projects in India: S.N Place Capac He Pow o. ity ad er 1. Vadodra(Gujar 1 m3/s 5 m 33 at) KW 2. Indore(M.P.) 0.6m3/ 5 m 19 s KW 3. Pune(Maharas 1.4 15 50 3 htra) m /s m KW 4. Korba(Chhattis 0.3 15 20 3 garh) m /s m KW 5. Mechuka(Arun 0.3m3/ 15 25 achal Pradesh) s m KW 6. Tato(Arunacha 0.3 15 20 3 l Pradesh) m /s m KW
Fig.-3 3. Comparison Between various turbines: [10] Turbine Type→
Screw Turbine
Efficien cy
Up to 90%.Re mains constant with varying load.
Output
Varies proporti onally to inlet flow conditio
Cross Flow Turbine Up to 85%.Re mains constant with varying load. Varies proporti onally to inlet flow
Kaplan Turbine Above 90%.Co mes down drastical ly at varying load. Require sa constant flow & Head to generate
Francis Turbin e Above 90%.Co mes down changes at varying load. Require sa constant flow & Head to generat
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ns and there is no risk of damage from running dry.
conditio ns.
Generati on Capacity
Good for 5 KW to 500 KW
Good for 5 KW to 100 KW
Head
Best for ranges from 1 m to 10 m Can work efficientl y from 0.2 m3/s to 10 m3/s Factory preassemble d, less civil work.
Best for ranges from 1.75 m to 40m Can work efficientl y from 0.04 m3/s to 5 m3/s Requires Penstock & Draft tube.
Installati on Period Durabili ty
2-3 months
5-6 months
Only Water required
Wear & Tear
Negligib le
Only clear water required High
Dischar ge
Ease Of Installati ons
power. Output comes down exponen tially at part inlet flow conditio n. Generall y, does not perform at low flow in summer season. Good for 75 KW to 5 MW Best for ranges from 2 m to 50 m Can work efficient ly from 3 m3/s to 30 m3/s Require s Penstoc k& Draft tube. Very expensi ve civil work. 10-12 months Only clear water required Very high
e power.
Up to 1000M W Best for ranges from 30 m to 800 m Approx. more than 1m
Require s Penstoc k& Draft tube. Very expensi ve civil work. More than 1 years Only clear water required Very high
Reliabili ty Mainten ance Environ ment Compati bility
Excellen t Negligib le Fish compati ble
Good
Good
Good
Regular
Regular
Regular
Fish incompa tible
Fish incompa tible
Fish incomp atible
3.1 Objectives of Micro Hydro Power Plant with Screw Turbine: Eco-friendly in nature & have zero effect on environment in the sense of pollution. Cutting of trees and displacement of people is not required. Suitable for power consumption of small villages or one or more than one families. Sources-renewable energy resources. Small canals, ponds & rivers etc. can be utilized as resources. Negligible maintenance & operation cost. Fish friendly. Easy & fast installation. Very less civil work required. High reliability. Efficient for low and variable water heads (Minimum 1m head). Durability (mode of operation). Low wear & tear. Cavitations & erosion cannot affect the turbine. Efficiency will remain same with respect to varying loads. No control system necessary. Efficiency is more as compared to water wheels & small turbine. Ultra long life at least 30 years. CO2 reduction. Natural flow of water i.e. no pressure built up. Wild life habitat will not be affected. 4. CONCLUSION: Dam having higher water holding capacity for large scale hydro power plants leads to many drastic problems including people displacement, deforestation, loss of agriculture land & earthquakes. Viz., they are some examples, an earthquake occurred at Latur & Ushmanabad ISBN-978-81-932091-2-7
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(Maharashtra) due to KOENA dam and at Jabalpur (MP) due to BARGI dam. Due to INDRA SAGAR dam the Harshood place was completely displaced & new Harshood was established known as Chhannera. Only Due to SARDAR SAROVAR dam at Narmada River (Gujrat) more than 2 lakhs people were displaced, 37 thousand hectares agriculture lands & 10713 hectares deforestation took place etc. There are many other several examples of these kind of dams due to which the mentioned problems are occurring. India is blessed with abundant hydro electrical potential, estimated 19749.44 MW, rank 5th in the world, in terms of utilizable potential. But when compared to other sources of micro hydro power, Screw turbine is negligible in consideration. It can give power to a particular house or one or more families or even to small villages. It has more efficiency and less transmission losses as compared to other power plants. According to survey, only 4389.55MW of power is generated by small hydro power plants, rather available potential is of thousands of MW but could not utilized 22% (approx.) in total. Some major states of India have even not installed & implemented these small power plants where potential is available. Using higher efficiency of screw turbines, local power requirement can be fulfilled, transmission losses can be reduced, more employment can be provided & nature can be preserved. References: (1.) https://en.wikipedia.org/wiki/Electricity_sector_ in_India. (2.) http://decarboni.se/publications/kyotoprotocol-1997 (3.) www.aprekh.org_files_RREST_AlokJindal (4.) www.mnre.gov.in (5.) http://en.wikipedia.org/wiki/Screw_turbine (6.) http://www.renewablesfirst.co.uk/hydrolearning-centre/archimedean-screw/ (7.) http://greenbugenergy.com/get-educatedknowledge/the-history-of-hydropower
(8.) http://josiah.berkeley.edu/2007Fall/ER200N/Re adings/Micro_Hydro_2007.pdf (9.) https://energypedia.info/wiki/Micro_Hydro_Po wer_(MHP)_Plants (10.) www.jashindia.com
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Solar Energy in India and National Solar Mission: A Review Mahendra Kumar Meena Department of Political Science, SGGG Banswara Raj. (India)
Introduction In global climate change regime, India has been regarded as a prominent player due to its huge population, developmental needs and great economic potential. Since the Earth Summit 1992, India has been playing a very crucial and pivotal role in shaping global environmental policies. In 1972, at Stockholm conference, Indian Prime minister Smt. Gandhi had described “poverty as a greatest polluter” and thus underscored India’s preference to the development to eradicate poverty. Thus, India’s policy stand in international climate change regime has been articulated around the equal right of development for each individual. India had successfully negotiated during the making of United Nation Framework for Climate Change(UNFCCC) and the inclusion of “common but Differentiated Responsibility” in article 7 of the Rio Declaration can be marked as grand success for India and hence for all developing nations.1 The principal of CBDR explicitly acknowledged the historical responsibility of developed countries in the degradation of the environment and hence, assigned the primary responsibility to the developed counties to avert climate change and its adverse effects. To secure energy needs for the development, India has always been in denial mode to accept any binding commitment to reduce its GHG emission despite being fourth largest GHG emitter (2341000 kts Co2, 2013)2. This Indian potion successfully went through Kyoto Protocol (1997) under immense pressure from the developed countries that India should embrace binding mitigation commitments. Under the furious pressure from the developed countries, just before G-8 summit in Japan (June 2008), Indian PM Dr. Manmohan Singh launched National Action Plan on Climate Change (NAPCC) 3 The NAPCC , with the
outline of its 8 National Mission, was approved by the Prime Minister’s Council on Climate Change (PMCCC), a 26- member apex advisory body, convened barely three week earlier without a thorough discussion.4 In launching India’s National Action Plan on Climate Change on June 30, 2008, the Prime Minister of India, Dr. Manmohan Singh stated: Our vision is to make India’s economic development energy-efficient. Over a period of time, we must pioneer graduated shift from economic activity based on fossil fuels to one based on non-fossil fuels and from reliance on non-renewable and depleting sources of energy to renewable sources of energy. In this strategy, the sun occupies center-stage, as it should, being literally the original source of all energy. We will pool our scientific, technical and managerial talents, with sufficient financial resources, to develop solar energy as a source of abundant energy to power our economy and to transform the lives of our people. Our success in this endeavor will change the face of India. It would also enable India to help change the destinies of people around the world.”5 It can be said that India has added renewable energy as an important alterative to its energy matrix to reduce GHG emission, which is mainly dominated by coal-based power production, To fulfill the international commitments made by India through ‘Intended Nationally Determined Contribution’(INDC) to the UNFCCC. Enormous business opportunities further, impetus the Indian policy makers to explore the potential of alternative energy sources in context of India’s energy security and to meet the huge energy requirement to fuel India’s development. India is geographically blessed with bright sunlight in most of its part, throughout the year. This nature’s blessing has tremendous potential ISBN-978-81-932091-2-7
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to produce clean solar power. The National Action Plan on Climate Change also points out: “India is a tropical country, where sunshine is available for longer hours per day and in great intensity. Solar energy, therefore, has great potential as future energy source. It also has the advantage of permitting the decentralized distribution of energy, thereby empowering people at the grassroots level”. Based on this vision a National Solar Mission is being launched under the brand name “Solar India”6
The Eight National Mission The operational content of the National Action Plan lies in the eight different National Missions, which were simultaneously announced by the Indian government. These are as: 1. National Solar Mission 2. National Mission for Enhanced Energy Efficiency 3. National Mission for Sustainable Agriculture 4. National Water Mission 5. National Mission o Sustainable Habitat 6. National Mission for sustaining the Himalayan Ecosystem 7. National mission for A Green India 8. National Mission for strategic Knowledge for Climate Change. Each Mission says NAPCC, ‘will be tasked to evolve specific objectives’ until financial year 2016-2017.It originally mandated the nodal ministries agencies to submit eight comprehensive mission documents by the end of 2008, to be approved by the PMCCC.7
JawharLal Nehru National Solar Mission The National Solar Mission was launched on the 11th January, 2010 by the Prime Minister. The Mission has set the ambitious target of deploying 20,000 MW of grid connected solar power by 2022 is aimed at reducing the cost of solar power generation in the country through (i) long term policy; (ii) large scale deployment goals; (iii) aggressive R&D; and (iv) domestic production of critical raw materials, components and products, as a result to achieve grid tariff parity by 2022. Mission will create an enabling policy
framework to achieve this objective and make India a global leader in solar energy. Further, Government has revised the target of Grid Connected Solar Power Projects from 20,000 MW by the year 2021-22 to 100,000 MW by the year 2021-22 under the National Solar Mission and it was approved by Cabinet on 17th June 2015.8
Importance and relevance of solar energy for India9 1. Cost: Solar is currently high on absolute costs compared to other sources of power such as coal. The objective of the Solar Mission is to create conditions, through rapid scale-up of capacity and technological innovation to drive down costs towards grid parity. The Mission anticipates achieving grid parity by 2022 and parity with coal-based thermal power by 2030, but recognizes that this cost trajectory will depend upon the scale of global deployment and technology development and transfer. The cost projections vary –from 22% for every doubling of capacity to a reduction of only 60% with global deployment increasing 16 times the current level. The Mission recognizes that there are a number of off-grid solar applications particularly for meeting rural energy needs, which are already cost-effective and provides for their rapid expansion. 2. Scalability: India is endowed with vast solar energy potential. About 5,000 trillion kWh per year energy is incident over India’s land area with most parts receiving 4-7 kWh per sq. m per day. Hence both technology routes for conversion of solar radiation into heat and electricity, namely, solar thermal and solar photovoltaics, can effectively be harnessed providing huge scalability for solar in India. Solar also provides the ability to generate power on a distributed basis and enables rapid capacity addition with short lead times. Off-grid decentralized and low-temperature applications will be advantageous from a rural electrification perspective and meeting other energy needs for power and heating and cooling in both rural and urban areas. The constraint on scalability will be the availability of space, since in all current ISBN-978-81-932091-2-7
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applications, solar power is space intensive. In addition, without effective storage, solar power is characterized by a high degree of variability. In India, this would be particularly true in the monsoon season. 3. Environmental impact: Solar energy is environmentally friendly as it has zero emissions while generating electricity or heat 4. Security of source: From an energy security perspective, solar is the most secure of all sources, since it is abundantly available. Theoretically, a small fraction of the tota incident solar energy (if captured effectively) can meet the entire country’s power requirements. It is also clear that given the large proportion of poor and energy un-served population in the country, every effort needs to be made to exploit the relatively abundant sources of energy available to the country. While, today, domestic coal-based power generation is the cheapest electricity source, future scenarios suggest that this could well change. Already, faced with crippling electricity shortages, price of electricity traded internally, touched Rs 7 per unit for base loads and around Rs 8.50 per unit during peak periods. The situation will also change, as the country moves towards imported coal to meet its energy demand. The price of power will have to factor in the availability of coal in international markets and the cost of developing import infrastructure. It is also evident that as the cost of environmental degradation is factored into the mining of coal, as it must, the price of this raw material will increase. In the situation of energy shortages, the country is increasing the use of diesel-based electricity, which is both expensive –costs as high as Rs 15 per unit -and polluting. It is in this situation the solar imperative is both urgent and feasible to enable the country to meet long-term energy needs. Objectives and Targets The objective of the National Solar Mission is to establish India as a global leader in solar energy, by creating the policy conditions for its diffusion across the country as quickly as possible The
Mission have adopted a 3-phase approach, spanning the remaining period of the 11th Plan and first year of the 12thPlan (up to 2012-13) as Phase 1, the remaining 4 years of the 12thPlan (2013-17) as Phase 2 and the 13th Plan (2017-22) as Phase 3. At the end of each plan, and mid-term during the 12thand 13th Plans, there will be an evaluation of progress, review of capacity and targets for subsequent phases, based on emerging cost and technology trends, both domestic and global. The aim would be to protect Government from subsidy exposure in case expected cost reduction does not materialize or is more rapid than expected. To achieve this, the Mission targets are: To create an enabling policy framework for the deployment of 20,000 MW of solar power by 2022. To ramp up capacity of grid-connected solar power generation to 1000 MW within three years –by 2013; an additional 3000 MW by 2017 through the mandatory use of the renewable purchase obligation by utilities backed with a preferential tariff. This capacity can be more than doubled –reaching 10,000MW installed power by 2017 or more, based on the enhanced and enabled international finance and technology transfer. The ambitious target for 2022 of 20,000 MW or more, will be dependent on the ‘learning ‘of the first two phases, which if successful, could lead to conditions of gridcompetitive solar power. The transition could be appropriately up scaled, based on availability of international finance and technology. To create favorable conditions for solar manufacturing capability, particular solar thermal for indigenous production and market leadership. To promote programmes for off grid applications, reaching 1000 MW by 2017 and 2000 MW by 2022. To achieve 15 million sq. meters solar thermal collector area by 2017 and 20 million by 2022. To deploy 20 million solar lighting systems for rural areas by 2022. ISBN-978-81-932091-2-7
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Mission Strategy (phase 1 and 2)10 The Mission has strategy to achieve its targets and objectives mainly through five ways; A. Utility connected applications: constructing the solar grid is the key driver for promoting solar power would be through a Renewable Purchase Obligation (RPO) mandated for power utilities, with a specific solar component. This will drive utility scale power generation, whether solar PV or solar thermal. The Solar Purchase Obligation will be gradually increased while the tariff fixed for solar power purchase will decline over time. B. The below 80°C challenge –solar collector: The Mission is setting an ambitious target for ensuring that applications, domestic and industrial, below 80°C are solarised. C. The off-grid opportunity -lighting homes of the power deprived poor: A key opportunity for solar power lies in decentralized and off-grid applications. In remote and far-flung areas where grid penetration is neither feasible nor cost effective, solar energy applications are costeffective. The Government has promoted the use of decentralized applications through financial incentives and promotional schemes. While the Solar Mission has set a target of 1000 MW by 2017, which may appear small, but its reach will add up to bringing changes in millions of households. D. Manufacturing capabilities: innovate, expand and disseminate: Currently, the bulk of India’s Solar PV industry is dependent on imports of critical raw materials and components –including silicon wafers. Proactive implementation of Special Incentive Package (SIPs) policy, to promote PV manufacturing plants, including domestic manufacture of silicon material, would be necessary. E. R&D for Solar India: creating conditions for research and application A major R&D initiative to focus: An ambitious human resource development programme, across the skill-chain,
will be established to support an expanding and large-scale solar energy programme, both for applied and R&D sectors. In Phase I, at least 1000 young scientists and engineers would be incentivized to get trained on different solar energy technologies as a part of the Mission’s long-term R&D and HRD plan.
The Road Map The aspiration is to ensure large-scale deployment of solar generated power for gridconnected as well as distributed and decentralized off-grid provision of commercial energy services. The deployment across the application segments is envisaged as Follows: Table 1: The Solar Mission’s Proposed Roadmap Sr.No
Application Segment
1
Solar Collector
2
OffGridSolar Application Utility Grid Power
3
Target Phase I (201013) 7 Million Sq. Metres 200MW
Target Phase II (2013-17)
Target phase III (2017-22)
15 Million Sq.Metres
20 million Sq.Metres
1000MW
200MW
10002000M W
400010000M W
20000M W
Source:The Ministry of New and Reneable Energy,GOI, JNNSM, N.Delhi, P.7
Economic Incentives: To achieve the leadership position in solar energy economic incentives to the solar industry is inevitable. Providing adequate loan facility, setting up solar parks, SEZ like facility for component manufacturing, wavier in custom duty, ease of doing business, single widow clearance, are some requirements t boost solar revolution in India. Importantly, Power purchase Agreement is essential part of solar business to ensure the economic viability of solar power. Again, the falling prices of solar power are creating positive sentiment and attracting investment to the solar industry. Upendra Tripathy, formerly secretary of the renewable energy ministry, “When we ISBN-978-81-932091-2-7
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started, people didn’t believe that solar was for real. They thought it was imaginary given that the tariffs were at Rs18 per unit. They thought it was a story which was being hyped. However, a lot of people including companies and financial institutions got interested. We called for open bidding and whatever was happening internationally, be it in terms of technology or falling solar PV (photovoltaic) prices got reflected here. With no cartels being formed, it helped India,”11 The solar space has already seen a significant decline in tariffs from Rs10.95-12.76 per kWh in 2010-11. The year 2017 has brought the prices further down. India’s solar power tariff hit a new low of Rs2.44 per unit on 12 May 2017 at the auction of 500 megawatt (MW) of capacity at the Bhadla solar park in Rajasthan.12 The decrease in solar power prices attributed to the decision of the Government of India to cover solar power by Solar Energy Corporation of India Ltd(SECI) under the ambit of tripartite agreement for payment security against defaults by State distribution companies13
Towards the Global Leader in Solar Power India launched an International Solar Alliance (ISA) at the CoP21 Climate Conference, with an announcement by Prime Minister Modi that the revolution in the field would bring power to all citizens, and create unlimited economic opportunity. Over 100 countries falling between tropics of Cancer and Capricorn have assured their participation in the alliance for which India will be providing the initial funding of Rs 175 References 1. Retrieved from http://www.un.org /documents/ga/conf151/aconf151261annex1. htm 2. World Bank Data, available on http://data.worldbank.org/indicator/SP.RU R.TOTL.ZS/countries/1W8S?display=default
crore. The alliance brings together sun-rich nations for a research and collaboration initiative that has the potential to change the face of future energy access. It will be a platform to benchmark low-cost solar solutions and will provide unique investment opportunity for the developing world. The initiative places India in a more assertive and constructive position on the international stage, no longer merely accepting the politics of climate change, but now shaping them via its diplomatic and geopolitical influence.14 Conclusion Country like India has very much unbalanced in electricity production. Production is less and consumption is very much. Solar power is very good option in India to increase power production. This is also very good for our environment protection and economic development. Solar power is unlimited source of energy and our country also provide suitable climate for this energy but we need some better idea to increase efficiency and decrease production cost. Our government launches some schemes for production of solar power and achieves some successes but we need education and publicity in society for these schemes so that people take some initiative for use renewable energy as much as at a place of conventional energy sources. Currently we are generating 4.59% of solar energy of total produced renewable energy installed capacity in India. It is very low in comparison of total installed capacity of renewable energy and scope is very much for this solar PV. 3. 4. 5. 6.
Prime minister’s Council on climate change,GOI,2008, NAPCCC, N.Delhi,http:// pmindia.nic.in/pg01-52.pdf. Praful Bidwai, “The politics of Climate Change and the Global Crisis’, p.129,Orient BlackSwan,2012 http://www.mnre.gov.in/filemanager/UserFiles /mission_document_JNNSM.pdf Ibid. ISBN-978-81-932091-2-7
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7.
Praful Bidwai, “The politics of Climate Change and the Global Crisis’, p.130,Orient BlackSwan,2012 8. Ibid. 9. http://www.mnre.gov.in/filemanager/UserFiles /mission_document_JNNSM.pdf 10. Ibid.
11. Solar Tariff ars heat up India, Livemint, 31 may 2017. 12. http://www.livemint.com/Industry/saGIF4 VEwvv38rf208tUAM/Solar-power-tarifffalls- further -to-Rs244-per-unit.html 13. Ibid. 14. Chetan Chauhan, “Pm Modi to launch Solar Alliance in Paris Summit”,Hindustan Times, Nov.30, 2015, N.Delhi
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Optimization Techniques Based Selective Harmonic Elimination for Multilevel Inverter with Reduced Number of Switches R. K. Kumawat*,1, D.K.Palwalia2 Department of Electrical Engineering Rajasthan Technical University Kota, India Corresponding Author:1rkkumawat.phd@rtu.ac.in, 2dkpalwalia@rtu.ac.in Abstract Multilevel inverter (MLI) is an alternative for high power and high voltage applications. It has low switching stress on power switches, lower total harmonic distortion (THD), higher efficiency and low Electromagnetic Interference (EMI). Higher number of power switches contributes complexity of control and high cost. In this paper a seven-level MLI is proposed with reduced switch count and improved performance. Selective Harmonic Elimination (SHE) that can be applied MLI ar desire switching frequency offers elimination of harmonics in output voltage. Also, by using SHE technique with cascade H-bridge multilevel inverters, the necessity of using filter in output can be minimized. In this paper, SHE equation have been solved by using Genetic Algorithms (GA) and NewtonRaphson Method. It has been aimed to eliminated desire harmonic order at fundamental output voltage and also have been analyzed and compared the harmonics. Keywords—Multilevel inverter(MLI), THD, PWM, Full-bridge, Half bridge INTRODUCTION DC to AC power conversion play a crucial role in recent years and implemented for high power and high voltage application. It attracts in power generation, energy transmission, distribution and utility application. It has been widely applied in variable frequency drive, power quality device, UPS, HVDC transmission, inducting heating, SVC, FACTS, marine propulsion, fuel cell, solar cell. Concept of multilevel inverter is lucrative solution in the medium and high voltage application with high power conversion and enhancement power quality [1–4]. it produce output voltage waveform with control frequency, amplitude and phase by controlling the semiconductor switches [5–8]. A two-level inverter use PWM operation with high switching frequency and eliminate the lower order harmonics. Issue with two level inverters is high switching frequency loss due to unavailability of high power high voltage semiconductor device. MLI provides a cost-effective solution with low distortion, reduced dv/dt stress, voltage limit capability of semiconductor switches, better harmonic profile, and high voltage capability. It can operate at both fundamental switching frequency and high switching frequency using pulse width modulation scheme [9–11]. For high voltage high power application such as power quality, renewable energy resource, adjustable
I.
speed drive, micro grid and power system control multilevel inverter received more attention. It is commercialized as three basic topology: neutral point clamped (NPC), flying capacitor (FC), and cascade H- bridge (CHB) [12–16]. Neutral point clamped is also known as diode clamped multilevel inverter. DC bus voltage split in N-level by series connected bulk capacitor threw fast switching diode. Drawback of NPC is higher number of diode and Dc-link voltage balancing as the number of level increase [17]. Capacitor clamped inverter required large number of clamping capacitor to clamp the output voltage by proper selection of capacitor combination [18]. Cascade H-bridge inverter consists of full bridge and half bridge module with all source connected in series at each phase. CHMLI have simplicity of control, lesser rating and least number of power semiconductor switches. It has no need of clamping diode and voltage balancing capacitor. It has less common node voltage, separate DC sources. To control the output voltage and eliminate harmonics a method is used for switching power semiconductor switches. Method for proper selection of switching angle such as space vector modulation (SVM), space vector pulse width modulation (SVPWM), sinusoidal pulse width modulation (SPWM), selective harmonic ISBN-978-81-932091-2-7
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elimination (SHE) has been conventionally used [19-21]. SVM or CBPWM technique based on High switching frequency modulation [22-24]. It leads to high switching losses and lower order harmonic producing high THD in output voltage. Due to this side band round carrier frequency appear. Low or fundamental switching frequency modulation based SHE technique has been developed for control of CHMLI. It has less switching losses and few communications per cycle. It maintains rapid power quality and direct control over output voltage harmonic. Equation produced by SHE-PWM are highly nonlinear transcendental, depends on solving a series of trigonometric equation and produced simple, multiple or no solution for fixed value modulation index. Thus, providing all possible and analytical solution using less computational complex method for SHE equation through extensive range of modulation index 0 to 1, has been big task for researcher. Another approach has been implemented to solve SHE equation based on converting transcendental equation in to polynomial equation [25-28]. Theory of symmetric and resultants of polynomials has been suggested to solve equation obtain from transcendental equation. For this approach, proper initial guess for switching angle and modulation index are required. It is challenging task to guess initial switching angle and modulation index for which solution exist. That approach is unattractive because degree of polynomial is in direct relation with inverter level hence polynomial is very complex, numerical difficulty, and computational burden. In this paper, the researchers have performed simulation for seven levels cascade H-bridge multilevel inverter, and used the selective harmonic elimination PWM switching method. PWM [29-30]. Selective harmonic elimination PWM switching method is utilized for controlling the gate signals of switching device. Switching angles are solved from the non-linear transcendental equations. For generating the optimized
staircase voltage waveform, the optimized switching angles are obtained using by Newton-Raphson technique and Genetic Algorithm technique (GA). If we know the good initial guesses then the results can be optimized well more. II. CONVENTIONAL CASCADE MULTILEVEL INVERTER Full bridge topology of cascade H-bridge with four switches, a DC voltage source is used to generate three levels square wave output voltage waveform. Cascade multilevel consists of series connection of multiple single phase modules with symmetric and asymmetric manner [25]. Each module generates voltage level include positive, negative and zero. Configuration of cascade H-bridge is shown in fig.1 Overall output voltage of multilevel inverter is given V0 Vdc1 Vdc 2 Vdc 3 ...........Vdcn (1) If the entire Dc voltage source in each module have equal the inverter is known as symmetric multilevel. The number of output voltage steps in symmetric multilevel inverter is N step 2n 1 (2) Maximum output voltage is due to the communication of switches is: Vo (max) n Vdc (3) Where n is the number of dc voltage source If the entire DC voltage sources in each module have unequal voltage level the inverter is known as asymmetric multilevel inverter. It can provide large number of output voltage steps without increasing the number of switches. The number of voltage steps and maximum output voltage are given as follow:
N step 2n1 1 (4) Vo(max) (2n 1) Vdc
(5)
p 1
If V 2 Vdc for p=1, 2, 3……, n p
N step 3n
(6)
(3n 1) Vdc 2 If V p 3 p 1Vdc for p=1, 2, 3……, n
Vo (max)
(7)
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S11
Edc1
Edc1
+
E01
+
S41
S21
S12
S32
S42
S22
-
+
E02
+
S1n
Edcn
S31
S3n
-
Eo
+
E0n
+
S4n
S2n
-
Fig.1. Configuration of cascade multilevel inverter III. ANALYSIS USING SELECTIVE HARMONIC ELEMINATION The selective harmonic elimination method is also known as programmed PWM or fundamental switching frequency method based on harmonic elimination theory. Assuming quarter wave symmetry and equal sources the staircase, output voltage can be given by the Fourier series expansion as follows: (đ?&#x2018;&#x17D; cos(đ?&#x2018;&#x203A;đ?&#x153;&#x201D;đ?&#x2018;Ą) + đ?&#x2018;Ł (đ?&#x153;&#x201D;đ?&#x2018;Ą ) = đ?&#x2018;&#x17D; + đ?&#x2018;? sin(đ?&#x2018;&#x203A;đ?&#x153;&#x201D;đ?&#x2018;Ą)) (8) Due to symmetricity, it does not contain even harmonic component đ?&#x2018;&#x17D; = â&#x2C6;Ť đ?&#x2018;Ł (đ?&#x153;&#x201D;đ?&#x2018;Ą )đ?&#x2018;&#x2018;đ?&#x2018;Ą (9) đ?&#x2018;&#x17D; = â&#x2C6;Ť đ?&#x2018;Ł (đ?&#x153;&#x201D;đ?&#x2018;Ą) cos(đ?&#x2018;&#x203A;đ?&#x153;&#x201D;đ?&#x2018;Ą)đ?&#x2018;&#x2018;đ?&#x2018;Ą
(10)
đ?&#x2018;? = â&#x2C6;Ť đ?&#x2018;Ł (đ?&#x153;&#x201D;đ?&#x2018;Ą) sin(đ?&#x2018;&#x203A;đ?&#x153;&#x201D;đ?&#x2018;Ą)đ?&#x2018;&#x2018;đ?&#x2018;Ą ( 11) Hence Fourier expression can be written as (đ?&#x2018;? sin(đ?&#x2018;&#x203A;đ?&#x153;&#x201D;đ?&#x2018;Ą)) đ?&#x2018;Ł (đ?&#x153;&#x201D;đ?&#x2018;Ą) = (12) , , The value of bn component is compute as (cos(đ?&#x2018;&#x203A;đ?&#x203A;ź ) + cos(đ?&#x2018;&#x203A;đ?&#x203A;ź ) +
đ?&#x2018;? = , ,
â&#x2039;Ż + cos(đ?&#x2018;&#x203A;đ?&#x203A;ź )) (13) Subjected to đ?&#x203A;ź < đ?&#x203A;ź < đ?&#x203A;ź < đ?&#x203A;ź â&#x20AC;Ś < đ?&#x203A;ź â&#x2030;¤đ?&#x153;&#x2039; 2 where â&#x20AC;&#x2DC;sâ&#x20AC;&#x2122; is number of H-bridge connected in cascade per phase and â&#x20AC;&#x2DC;nâ&#x20AC;&#x2122; is order of harmonics. If Vdc is input DC voltage for n single phase H-
bridge are connected per phase hence total output voltage per phase is given by đ?&#x2018;Ł (đ?&#x153;&#x201D;đ?&#x2018;Ą) = đ?&#x2018;Ł (đ?&#x153;&#x201D;đ?&#x2018;Ą ) + đ?&#x2018;Ł (đ?&#x153;&#x201D;đ?&#x2018;Ą) + đ?&#x2018;Ł (đ?&#x153;&#x201D;đ?&#x2018;Ą ) + â&#x2039;Ż + đ?&#x2018;Ł (đ?&#x153;&#x201D;đ?&#x2018;Ą ) (14) Non-liner fundamental equation for the odd harmonic component is given by (cos(đ?&#x203A;ź ) + cos(đ?&#x203A;ź ) + â&#x2039;Ż + cos(đ?&#x203A;ź )) = đ?&#x2018;Ł (15) Generally, for s number of switching angles, one angle is used for desire fundamental output voltage V1 and remaining (s-1) switching angle are used to eliminate certain lower order harmonics. The relation between fundamental voltage and maximum fundamental voltage V1max is given by modulation index â&#x20AC;&#x2DC;mâ&#x20AC;&#x2122;. The modulation index is defined as the ratio of fundamental output voltage V1 to maximum fundamental voltage V1max. Maximum fundamental voltage is obtained when all switching angle are zero. đ?&#x2018;&#x2030; = hence the expression for â&#x20AC;&#x2DC;mâ&#x20AC;&#x2122; đ?&#x153;&#x2039;đ?&#x2018;Ł đ?&#x2018;&#x161;= 4đ?&#x2018; đ?&#x2018;Ł đ?&#x2018;Ł =đ?&#x2018;&#x161; for 0<mâ&#x2030;¤1 Thus, nonlinear transcendental equation is formed and after solving these equation modulation index and switching angle (đ?&#x203A;ź đ?&#x2018;Ąđ?&#x2018;&#x153; đ?&#x203A;ź ) characterizing the harmonic contain in output waveform. To eliminate 3rd ,5th ,7th and 9th harmonic đ?&#x2018;Ł , đ?&#x2018;Ł , đ?&#x2018;Ł and đ?&#x2018;Ł are set to zero. (cos(đ?&#x203A;ź ) + cos(đ?&#x203A;ź ) + cos(đ?&#x203A;ź ) + â&#x2039;Ż + cos(đ?&#x203A;ź )) = đ?&#x2018; đ?&#x2018;&#x161; (cos(3đ?&#x203A;ź ) + cos(3đ?&#x203A;ź ) + cos(3đ?&#x203A;ź ) + â&#x2039;Ż + cos(3đ?&#x203A;ź )) = 0 (cos(5đ?&#x203A;ź ) + cos(5đ?&#x203A;ź ) + cos(5đ?&#x203A;ź ) + â&#x2039;Ż + cos(5đ?&#x203A;ź )) = 0 (cos(7đ?&#x203A;ź ) + cos(7đ?&#x203A;ź ) + cos(7đ?&#x203A;ź ) + â&#x2039;Ż + cos(7đ?&#x203A;ź )) = 0 (cos(9đ?&#x203A;ź ) + cos(9đ?&#x203A;ź ) + cos(9đ?&#x203A;ź ) + â&#x2039;Ż + cos(9đ?&#x203A;ź )) = 0 (16) The foremost objective is to minimizing the nonlinear transcendental equation set, which is express as đ?&#x2018;&#x201C;(đ?&#x203A;ź , đ?&#x203A;ź , đ?&#x203A;ź â&#x20AC;Ś â&#x20AC;Ś . đ?&#x203A;ź ) Subjected to đ?&#x203A;ź <đ?&#x203A;ź <đ?&#x203A;ź <đ?&#x203A;ź â&#x20AC;Ś<đ?&#x203A;ź â&#x2030;¤đ?&#x153;&#x2039; 2 ISBN-978-81-932091-2-7
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There are number of approach to solve nonlinear transcendental equation. By converting nonlinear transcendental equation in to polynomial equation with resultant method all possible solution for any number of level can be compute when they exist. Total harmonic4. distortion for corresponding solution compute by %đ?&#x2018;&#x2021;đ??ťđ??ˇ =
Ă&#x2014; 100
(17) IV. SOLVING SHE EQUATION USING 5. OPTIMIZATION TECHNIQUE In earlier section, SHE has been implemented on CHMLI configuration and nonlinear transcendental SHE equations set have been developed. In order get feasible solution during completed range of modulation index (m) from 0 to 1 which give less %THD has been challenge task for researchers hence deterministic and stochastic algorithms have been developed. A well-known Newton-Raphson (NR) method comes under deterministic or iterative approach and stochastic optimization techniques includes6. Continuous-Genetic Algorithm (C-GA) and Modified Species based Particle Swarm Optimization (MSPSO). This section explains newton Raphson method optimization algorithm to solve SHE equation. V. SOLVING USING NEWONS RAPHSON METHOD Newton's method was first designated by Isaac a. Newton in 1969, twenty years later Joseph Raphson got close to Newtonâ&#x20AC;&#x2122;s approach but b. only for polynomials of degree 3,4,5â&#x20AC;Ś10. In 1740, Thompson Simpson explained NR methodc. as an iterative method to solve optimization problems by setting the gradient to zero. First implementations of Newtonâ&#x20AC;&#x2122;s method to solve d. SHE equations to eliminate %THD in CHMLI is e. by H. S. Patel & R. G. Hoft in 1973. Later in literature several researchers have used Newton's method to solve nonlinear transcendental SHE f. equations. To solve nonlinear transcendental equations Newton-Raphson method is one of the g. traditionally preferred iterative methods This method based on calculus approach which is powerful and fast-iterative method to reach h. global minimum. It begins with an initial guess and generally converges at a zero. Basic requirement of NR method is good initial guess. If the initial guess is good, rate of convergence is fast and computational time is reduced. The
steps are 1. 2. 3.
involved in development of the algorithm The switching angle matrix đ?&#x203A;ź = [đ?&#x203A;ź đ?&#x203A;ź đ?&#x203A;ź đ?&#x203A;ź đ?&#x203A;ź ] The nonlinear system matrix
đ??š = â&#x17D;Ą cos đ?&#x203A;ź â&#x17D;˘cos â&#x17D;˘ â&#x17D;˘cos â&#x17D;˘cos â&#x17D;˘ â&#x17D;Łcos
cos đ?&#x203A;ź
cos đ?&#x203A;ź
cos đ?&#x203A;ź
cos đ?&#x203A;ź
3đ?&#x203A;ź
cos 3đ?&#x203A;ź
cos 3đ?&#x203A;ź
cos 3đ?&#x203A;ź
5đ?&#x203A;ź
cos 5đ?&#x203A;ź
cos 5đ?&#x203A;ź
cos 5đ?&#x203A;ź
7đ?&#x203A;ź
cos 7đ?&#x203A;ź
cos 7đ?&#x203A;ź
cos 7đ?&#x203A;ź
9đ?&#x203A;ź
cos 9đ?&#x203A;ź
cos 9đ?&#x203A;ź
cos 9đ?&#x203A;ź
â&#x17D;¤ cos 3đ?&#x203A;ź â&#x17D;Ľ â&#x17D;Ľ cos 5đ?&#x203A;ź â&#x17D;Ľ cos 7đ?&#x203A;ź â&#x17D;Ľ â&#x17D;Ľ cos 9đ?&#x203A;ź â&#x17D;Ś
And its derivate đ?&#x2018;&#x2018;đ?&#x2018;&#x201C; đ?&#x2018;&#x2018;đ?&#x203A;ź â&#x17D;Ą â&#x2C6;&#x2019; sin â&#x17D;˘ â&#x2C6;&#x2019;3sin â&#x17D;˘ = â&#x17D;˘â&#x2C6;&#x2019;5 sin â&#x17D;˘â&#x2C6;&#x2019;7 sin â&#x17D;˘ â&#x17D;Ł â&#x2C6;&#x2019;9sin
đ?&#x203A;ź
â&#x2C6;&#x2019; sin đ?&#x203A;ź
â&#x2C6;&#x2019; sin đ?&#x203A;ź
â&#x2C6;&#x2019; sin đ?&#x203A;ź
3đ?&#x203A;ź
â&#x2C6;&#x2019;3 sin 3đ?&#x203A;ź
â&#x2C6;&#x2019;3 sin 3đ?&#x203A;ź
â&#x2C6;&#x2019;3sin 3đ?&#x203A;ź
5đ?&#x203A;ź
â&#x2C6;&#x2019;5 sin 5đ?&#x203A;ź
â&#x2C6;&#x2019;5 sin 5đ?&#x203A;ź
â&#x2C6;&#x2019;5 sin 5đ?&#x203A;ź
7đ?&#x203A;ź
â&#x2C6;&#x2019;7 sin 7đ?&#x203A;ź
â&#x2C6;&#x2019;7 sin 7đ?&#x203A;ź
â&#x2C6;&#x2019;7 sin 7đ?&#x203A;ź
9đ?&#x203A;ź
â&#x2C6;&#x2019;9 sin 9đ?&#x203A;ź
â&#x2C6;&#x2019;9 sin 9đ?&#x203A;ź
â&#x2C6;&#x2019;9 sin 9đ?&#x203A;ź
â&#x2C6;&#x2019;sin đ?&#x203A;ź â&#x17D;¤ â&#x2C6;&#x2019;3 sin 3đ?&#x203A;ź â&#x17D;Ľ â&#x17D;Ľ â&#x2C6;&#x2019;5 sin 5đ?&#x203A;ź â&#x17D;Ľ â&#x2C6;&#x2019;7 sin 7đ?&#x203A;ź â&#x17D;Ľ â&#x17D;Ľ â&#x2C6;&#x2019;9 sin 9đ?&#x203A;ź â&#x17D;Ś
The corresponding harmonic amplitude matrix đ?&#x2018;&#x161;đ?&#x153;&#x2039; 0 0 0 0 4 Above Following equation can be written as đ??š (đ?&#x203A;ź) = đ?&#x2018;&#x2021; Statement of algorithm can be written as Guess the initial value for đ?&#x203A;ź with đ?&#x2018;&#x2014; = 0 Assume đ?&#x203A;ź = [đ?&#x203A;ź đ?&#x203A;ź đ?&#x203A;ź đ?&#x203A;ź đ?&#x203A;ź ] Calculate the value of đ?&#x2018;&#x201C; (đ?&#x203A;ź ) = đ??š Linearize function đ??š(đ?&#x203A;ź) = đ?&#x2018;&#x2021; about đ?&#x203A;ź đ?&#x153;&#x2022;đ?&#x2018;&#x201C; đ??š + đ?&#x2018;&#x2018;đ?&#x203A;ź = đ?&#x2018;&#x2021; đ?&#x153;&#x2022;đ?&#x203A;ź đ?&#x2018;&#x2018;đ?&#x203A;ź = [đ?&#x2018;&#x2018;đ?&#x203A;ź đ?&#x2018;&#x2018;đ?&#x203A;ź đ?&#x2018;&#x2018;đ?&#x203A;ź đ?&#x2018;&#x2018;đ?&#x203A;ź đ?&#x2018;&#x2018;đ?&#x203A;ź ] Calculate the value of đ?&#x2018;&#x2018;đ?&#x203A;ź đ?&#x153;&#x2022;đ?&#x2018;&#x201C; đ?&#x2018;&#x2018;đ?&#x203A;ź = đ??źđ?&#x2018; đ?&#x2018;&#x2030; (đ?&#x2018;&#x2021; â&#x2C6;&#x2019; đ??š ) đ?&#x153;&#x2022;đ?&#x203A;ź Updated initial guess values are đ?&#x203A;ź = đ?&#x203A;ź + đ?&#x2018;&#x2018;đ?&#x203A;ź Repeat the process for above equation until equation đ?&#x2018;&#x2018;đ?&#x203A;ź satisfy the desire solution and satisfy the following condition 0<đ?&#x203A;ź <đ?&#x203A;ź <đ?&#x203A;ź â&#x2030;¤đ?&#x153;&#x2039; 2 VI. GENETIC ALGORITHM TECHNIQUE In order to ease the complexity of controlling modern industries with multiple objectives and constraints, many researchers have developed đ?&#x2018;&#x2021;=
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biologically inspired algorithms and proved their effectiveness of control compared to derivative approaches. Genetic algorithm is one of the Stochastic optimization (SO) methods to solve nonlinear transcendental equations effectively. GAs is a subclass of Evolutionary computing and are random search algorithms. Though, all minimum seeking algorithms uses the same basic approach of heading downhill from an arbitrary starting point but they differ in deciding in which direction to move and how far to move (Davis 1991). After Successive improvements like increasing the speed of search process with good intelligence, without trapping at local minimum, powerful and widely accepted biologically inspired algorithm of Genetic Algorithm has been proposed by John Hallond in 1975 and finally it has been popularized by one of his student Goldberg who has solved the complex problem of control of gas-pipe line transmission for his dissertation work (Chamber 1995). Later it has been successfully implemented for solving number of engineering optimization problems due to the advantages such as Optimization with continuous or discrete variables, no need of calculus information, capability of dealing with a large number of variables, well suited for parallel computers, ability to find optimum global minimum instead of local minimum even in most complex objective functions (Sivanandam & Deepa 2011); (Deb 2001).
Start
Find No. of Variable Set population size Evaluate fitness function
If No. of iterations less then 100
No
Yes GA operation
No
If cost function less then 1 Yes stop
VII. SIMULATION RESULTS All simulating results and work is done on MATLAB 2012a package. Selective harmonic elimination pulse width modulation (SHE-PWM) switching method is used for controlling the cascade multilevel inverter, and the nonlinear transcendental trigonometric Eq. 16 and objective fitness function are solved and optimized by applying both of proposed newton-raphson (NR) methods and GA techniques respectively.
In this work, Continuous Genetic Algorithm has been used to solve nonlinear transcendental SHE equations during whole range of MI from 0 to 1. Steps involved in Continuous GA are as follows Step 1: Defining of optimization variables, cost function, cost. (cost minimization). Step 2: Generation of initial population. Step 3: Fitness/Cost evaluation. Step 4: Selection of Mates. Step 5: Mating. Step 6: Mutation. Step 7: Convergence check. Step 8: Repeat step (2) to step (7) until requirements met. Detailed explanation of algorithm is presented in (Ozpineci et al. 2005).
Figure 2: Switching angles versus modulation index for NR Method The simulating results are discussed for singlephase inverter with separate equal and constant dc sources. Each separate source has 24 volts, and case is studied for modulation index range from 0 to 1. Optimized results for cascade multilevel inverter are obtained at particular modulation indexes where the THD is lowest. Modulation index versus switching angles, ISBN-978-81-932091-2-7
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8
10
12
14
16
18
20
% THD
Modulation Index
Figure 4: THD versus modulation index for NR Method
Figure 5: THD versus modulation index for GA Method VIII. CONCLUSION New configuration of cascaded multilevel inverter has been proposed in this paper with a view to obtain all possible additive and subtractive combinations of the input DC level in the output voltage waveform. Suggested topologies need fewer switches and gate driver circuits with minimum standing voltage on
0.9145
0.8214 5.33
6.19 37.27 24.46 23.32
6
12.69
0
4.82
0.2
0.97
0.4
GA
0.6
62.67
0.8
54.41
1
TABLE I Switching Angles, THD and Computational Time
Figure 3: Switching angles versus modulation index for GA Method
34.83
12
20.93
10
11.66
8
0.755
6
Modulation Index
NR
4
đ?&#x203A;ź
2
đ?&#x203A;ź
0
đ?&#x203A;ź
0
đ?&#x203A;ź
20
đ?&#x203A;ź
40
%THD
60
Switching Angle
mi alpha1 alpha2 alpha3 alpha4 alpha5
80
Modulation Index
100
Computational Time (secs)
switches for realizing Nstep for the load. Therefore, the proposed topology results in reduction of installation area and cost and has simplicity of control system. The Newton-Raphson and GA techniques for harmonics elimination have been compared for equal and constant dc source cascade H-bridge inverter. Optimized angles have been obtained by
Method
THD, and frequency versus are shown in Fig.2Fig. 5.
solving the SHE problem. The total harmonic distortion (THD) for voltages have been reduced in more amount using GA techniques rather than Newton-Raphson technique, but NewtonRaphson takes time lesser than GA. REFERENCES [1] N. S. Choi, J. G. Cho, and G. H. Cho, â&#x20AC;&#x153;A general circuit topology of multilevel inverter,â&#x20AC;? in Power Electronics Specialists Conference, 1991. PESCâ&#x20AC;&#x2122;91 Record., 22nd Annual IEEE, 1991, pp. 96â&#x20AC;&#x201C;103. ISBN-978-81-932091-2-7
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[2] L. G. Franquelo, J. Rodriguez, J. I. Leon, S. Kouro, R. Portillo, and others, “The age of multilevel converters arrives,” Industrial Electronics Magazine, IEEE, vol. 2, no. 2, pp. 28–39, 2008. [3] P. W. Hammond, “A new approach to enhance power quality for medium voltage drives,” in Petroleum and Chemical Industry Conference, 1995. Record of Conference Papers., Industry Applications Society 42nd Annual, 1995, pp. 231–235. [4] Rakesh Kumar Kumawat, Seema Agrawal, Seemant Chourasiya , Dr.D.K.Palwalia, “A Comparative Study of Power Inverter Topology and Control Structures for Renewable Energy Recourses” , IARJSET, NCREE-2015, Vol. 2, Special Issue 1, May 2015,pp 350-354, ISSN (Online) 23938021, ISSN (Print) 2394-1588. [5] J.-S. Lai and F. Z. Peng, “Multilevel converters-a new breed of power converters,” Industry Applications, IEEE Transactions on, vol. 32, no. 3, pp. 509– 517, 1996. [6] T. Meynard and H. Foch, “Multi-level choppers for high voltage applications,” EPE journal, vol. 2, no. 1, pp. 45–50, 1992. [7] F. Z. Peng and J.-S. Lai, “Multilevel cascade voltage source inverter with seperate DC sources.” Google Patents, 1997. [8] Amit Kumar Sharma, Rakesh Kumar Kumawat & Ashok Kumar Sharma, “Simulation Of Ac To Ac Converter Fed Induction Motor For Fault Detection And Reduced Harmonic Content”, International Journal of Electrical and Electronics Engineering Research, Engineering Research (IJEEER) ISSN(P): 2250-155X; ISSN(E): 2278-943X Vol. 4, Issue 5, Oct 2014, 53-62. [9] F. Z. Peng, J.-S. Lai, J. W. McKeever, and J. VanCoevering, “A multilevel voltagesource inverter with separate DC sources for static var generation,” Industry Applications, IEEE Transactions on, vol. 32, no. 5, pp. 1130–1138, 1996. [10] L. M. Tolbert, F. Z. Peng, and T. G. Habetler, “Multilevel converters for large electric drives,” Industry Applications, IEEE Transactions on, vol. 35, no. 1, pp. 36–44, 1999.
[11] J. Rodriguez, L. G. Franquelo, S. Kouro, J. I. Leon, R. C. Portillo, M. Aá. M. Prats, and M. A. Perez, “Multilevel converters: An enabling technology for high-power applications,” Proceedings of the IEEE, vol. 97, no. 11, pp. 1786–1817, 2009. [12] L. M. Tolbert and F. Z. Peng, “Multilevel converters as a utility interface for renewable energy systems,” in Power Engineering Society Summer Meeting, 2000. IEEE, 2000, vol. 2, pp. 1271–1274. [13] Seema Agarwal, Seemant Chourasiya, Rakesh Kumar Kumawat, Dr. D. K. Palwalia, “Performance Analysis of Standalone Hybrid PVSOFC- BATTERY Generation System”, IARJSET, NCREE2015, Vol. 2, Special Issue 1, May 2015, pp 49-53, ISSN (Online) 2393-8021, ISSN (Print) 2394-1588. [14] W. Zhao, H. Choi, G. Konstantinou, M. Ciobotaru, and V. G. Agelidis, “Cascaded H-bridge multilevel converter for largescale PV grid-integration with isolated DCDC stage,” in Power Electronics for Distributed Generation Systems (PEDG), 2012 3rd IEEE International Symposium on, 2012, pp. 849–856. [15] A. Lesnicar and R. Marquardt, “An innovative modular multilevel converter topology suitable for a wide power range,” in Power Tech Conference Proceedings, 2003 IEEE Bologna, 2003, vol. 3, p. 6–pp. [16] L. Lin, Y. Zou, Z. Wang, and H. Jin, “Modeling and control of neutral-point voltage balancing problem in three-level NPC PWM Inverters,” in Power Electronics Specialists Conference, 2005. PESC’05. IEEE 36th, 2005, pp. 861–866. [17] M. Malinowski, K. Gopakumar, J. Rodriguez, and M. A. Perez, “A survey on cascaded multilevel inverters,” Industrial Electronics, IEEE Transactions on, vol. 57, no. 7, pp. 2197–2206, 2010. [18] A. Nabae, I. Takahashi, and H. Akagi, “A new neutral-point-clamped PWM inverter,” Industry Applications, IEEE Transactions on, no. 5, pp. 518–523, 1981. [19] F. Z. Peng, W. Qian, and D. Cao, “Recent advances in multilevel converter/inverter topologies and applications,” in Power ISBN-978-81-932091-2-7
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Electronics Conference (IPEC), 2010 International, 2010, pp. 492â&#x20AC;&#x201C;501. [20] J. Rodriguez, S. Bernet, P. K. Steimer, and I. E. Lizama, â&#x20AC;&#x153;A survey on neutral-pointclamped inverters,â&#x20AC;? Industrial Electronics, IEEE Transactions on, vol. 57, no. 7, pp. 2219â&#x20AC;&#x201C;2230, 2010. [21] X. Yuan and I. Barbi, â&#x20AC;&#x153;Fundamentals of a new diode clamping multilevel inverter,â&#x20AC;? Power Electronics, IEEE Transactions on, vol. 15, no. 4, pp. 711â&#x20AC;&#x201C;718, 2000. [22] R. Kumawat and D. Palwalia, "A novel PWM control for asymmetric multilevel inverter based on half bridge module," in Power India International Conference (PIICON), 2016 IEEE 7th, Bikaner, India, 2016, pp. 1-5, 2016. [23] F. Peng, J. McKeever, and D. Adams, â&#x20AC;&#x153;Cascade multilevel inverters for utility applications,â&#x20AC;? in Industrial Electronics, Control and Instrumentation, 1997. IECON 97. 23rd International Conference on, 1997, vol. 2, pp. 437â&#x20AC;&#x201C;442. [24] E. Villanueva, P. Correa, J. Rodrđ?&#x161;¤guez, and M. Pacas, â&#x20AC;&#x153;Control of a single-phase cascaded H-bridge multilevel inverter for grid-connected photovoltaic systems,â&#x20AC;? industrial Electronics, iEEE Transactions on, vol. 56, no. 11, pp. 4399â&#x20AC;&#x201C;4406, 2009. [25] E. Babaei, â&#x20AC;&#x153;A cascade multilevel converter topology with reduced number of switches,â&#x20AC;? Power Electronics, IEEE Transactions on, vol. 23, no. 6, pp. 2657â&#x20AC;&#x201C;2664, 2008. [26] E. Babaei and S. H. Hosseini, â&#x20AC;&#x153;New cascaded multilevel inverter topology with minimum number of switches,â&#x20AC;? Energy Conversion and Management, vol. 50, no. 11, pp. 2761â&#x20AC;&#x201C;2767, 2009. [27] J. Ebrahimi, E. Babaei, and G. B. Gharehpetian, â&#x20AC;&#x153;A new multilevel converter topology with reduced number of power electronic components,â&#x20AC;? Industrial Electronics, IEEE Transactions on, vol. 59, no. 2, pp. 655â&#x20AC;&#x201C;667, 2012. [48] G. Vijay and D. Palwalia, "A Novel Analysis and Modeling of Boost And Buck Converter," International Journal of Electronics, Electrical and Computational System, vol. 6, pp. 239-243, March 2017. [29] T. Lakshmi, N. George, S. Umashankar, and D. Kothari, â&#x20AC;&#x153;Cascaded seven level inverter
with reduced number of switches using level shifting PWM technique,â&#x20AC;? in Power, Energy and Control (ICPEC), 2013 International Conference on, 2013, pp. 676â&#x20AC;&#x201C;680. [30] N. A. Rahim, K. Chaniago, and J. Selvaraj, Single-phase seven-level grid-connected inverter for photovoltaic system,â&#x20AC;? Industrial Electronics, IEEE Transactions on, vol. 58, no. 6, pp. 2435â&#x20AC;&#x201C;2443, 2011. BIOGRAPHIES R.K.Kumawat Bâ&#x20AC;&#x2122;91, in Sikar Rajasthan received the B.Tech degree in Electrical Engineering from Jaipur National University, Jaipur, India, in 2011; the M.Tech degree in Power System from University College of Engineering, RTU, Kota, India in 2014.Where he has been pursing Ph.D degree in Power Electronic and Drive since 2014. His research interest includes power electronic for renewable energy, multilevel converters and electrical machine. Dr.D.K.Palwalia, Bâ&#x20AC;&#x2122;76, in Ajmer Rajasthan have received his B.Tech & M.Tech in 96 and 98 respectively. He obtained his Ph.D form IIT Roorkee in 2010. He is working as Associate Professor in Electrical Engineering Department at University College of Engineering, RTU, Kota. His research interest are power electronic & Drive, renewable energy, induction generator and digital control design
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Techno-economic Analysis of Solar Photovoltaic Cooling System: an analysis in four different climates in India B.L.Gupta Department of Mechanical Engineering, Govt. Engineering College Bharatpur (Raj.) Email: blgbharatpur@gmail.com, M â&#x20AC;&#x201C; (0) 9414810114
Abstract This study covers the techno- economic analysis of solar energy-based cooling system using photovoltaic (PV) technology for an office building located in four different climatic zones of India using simulation techniques. For Cooling technology multiple options have been considered; Mono crystalline, Poly crystalline and thin film cells. The building geometry, user profile and construction have been considered identical for chosen locations in four climatic zones; Ahmedabad from hot and dry zone, Bangalore from moderate zone, Chennai from warm and humid zone and Delhi from composite zone. The building modeling has been done using Google sketch up software while the simulation has been carried using TRNSYS v-17 software. The cooling load of the building varies with the climatic zones. Technically solar photovoltaic cooling system is possible having the solar fraction in the range of 0.24-0.57 and Primary energy savings reaches 57 % in the hot and dry climate. In this way the carbon dioxide (CO2) emission is also avoided. The payback periods, are higher in all the climate zones and the least being 14.23 years for the hot and dry climate. When PV based systems are optimally used with net metering provisions during the non-cooling periods then the payback period is 4-6 years for all climate zones. On the basis of techno-economic analysis, it is recommended that considering the prevailing costs and performance levels, net metering scheme should be immediately introduced in all states.
1. Introduction To improve the thermal comfort conditions, particularly in the summer season, there is growing demand of conventional vapour compression air conditioners. This growing demand not only increases electricity consumption but also global warming. Building architectural characteristics and trends like increasing ratio of transparent to opaque surfaces in the building envelope to even popular glass buildings has also significantly increased the thermal load on the air conditioners (Henning 2007). The conventional vapour compression refrigeration cycle driven by grid electricity increases the real cost of development. Firstly, it strongly increases the consumption of electricity and fossil energy. Energy sources based on fossil fuels such as coal, oil, gas, and nuclear energy sources etc., are either diminishing or are scarce in nature, location and volume hence a serious energy deficiency threat. In addition, it causes serious environmental hazards by releasing poisonous gases. One of the major environmental issues is acid rain resulting from
sulphurous gases emitted from power plants, killing sensitive living species, disrupting complex soil chemistry and affecting human health. Greenhouse gases such as CO2 (by product of combustion of fossil fuels), CH4, N2O, and halocarbons released from human activities absorb outgoing energy from the earth and cause warming effects. Secondly, the refrigerants like chlorofluocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) and hydrofluocarbons (HFCs) are also responsible for ozone depletion and global warming (Fan et al. 2007). UN Intergovernmental Panel on Climate Change (IPCC) warned that the average global temperature may increase by 1.4-4.5 K till 2100. The average global temperature has already risen by 0.6 K in the last century. In such a scenario, Kyoto Protocol adopted in 1997, a legally binding agreement under which the industrialized countries agreed to reduce their collective greenhouse gases by 5.2% compared to the year 1990. In Europe HFC-134a was banned for the air conditioning units in the new cars starting from 1 January 2009 (Kim 2008). In the present work parametric study and performance analysis of solar photovoltaic ISBN-978-81-932091-2-7
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cooling systems has been performed considering the annual solar fraction and relative primary energy savings. Three types of photovoltaic panel have been taken for the solar photovoltaic cooling (mono crystalline, poly crystalline and thin film). For performance analysis, Ahmedabad represents hot and dry climate, Bangalore represents moderate climate, Chennai represents warm and humid climate and Delhi represents composite climate. The cooling load of the building is different due to the climatic condition and consequently the system performance also differs. Financial viability of the cooling system has been examined through comparison with the energy consumption of conventional cooling system for producing the same cooling effect. Payback period is also calculated. 2. Solar photovoltaic cooling systems This system is simulated using TRNSYS program v-17. In this cooling system the packaged terminal air conditioner of 10 TR has been chosen operated by the electrical power supplied by the photovoltaic panel. If the power generated by the photovoltaic panel is less than required by the air conditioner then the remaining power will be taken from the grid. If the power generated by the photovoltaic panel is greater than required by the air conditioner then the remaining power will be supplied to the grid. The system is simulated using the three types of panels, mono-crystalline, polycrystalline and thin film cell. PV PANEL Building Type56
Weather data Type-15
INVERTER
AIR CONDITIONER
Solar Air Conditioning. The building being used in this research work is an office building with square envelope of 15m length and 15 m width. The height of the Building is 3.5 meters and total floor area is 225 m2. Building is divided in the five zones having orientation towards north. The entire building is used for office purpose in the day time only and whole area is conditioned. Windows on all four sides together constitute a WWR of 26%. The detail dimension of Building is shown in the Table 2 and in the Fig 2. Building envelope consists of the parts of building that separate the controlled indoor environment from the uncontrolled outdoor environment. It includes the walls, floor, roof and fenestration (windows, door). Walls, roof and window thickness and materials are selected such that the U-value of construction meets the ECBC requirement. Table 3 shows the complete details of U-value used here.
Fig.2:3 D view of Building Table 2 : Building Zone area and Internal load on Building S . N o 1 2 3
MIXTURES
PSYCHROMETRIC CHART
THERMOSTATE
Fig 1 Schematic of Solar Photovoltaic Cooling System 3. Specification of Building coupled with
2 3
Compon ent Zone Vol.(m3 ) Zone Area(m2 ) WWR (%) Infiltrati on (ACH) Ventilati on(ACH
Wes t Zon e 143. 64
Nor th Zon e 143. 64
Core Zone 212.9 4
East Zone 143.6 4
South Zone 143.64
60.84
41.04
41.0 4
41.0 4
41.04
-
27
27
23
27
0.2
0.2
0.2
0.2
0.2
0.75
0.75
0.75
0.75
0.75
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6 7
10.8
10.8
10.8
10.8
10.8
8
6
6
6
6
80
80
80
80
80
09001800
09001800
090 0180 0
090 0180 0
09001800
4. Result and Discussion 4.1 Annual cooling load analysis The cooling load of the five zone buildings having a conditioning area of 225 m2 are determined using TRNSYS program. From the building cooling model, the cooling load can be determined partly as infiltration gain, ventilation gain, sensible gain and latent gain. The total cooling load of a building is the summation of infiltration, ventilation, internal gain and solar gain through walls, windows and roof. The infiltration load is due to cracks, fenestration in the walls and roof, whereas ventilation load is due to fresh air supplied to the building. The person sitting inside the building also has a part of sensible and a part of latent heat load. Lighting, equipment, is also responsible for the cooling load. The major part of the load is by solar gain through the walls and windows depending on the U value of the construction materials. In this study the building load is calculated by using TRNSYS simulation program for four cities situated in four different climate conditions. Fig.3 shows the annual cooling demand and peak cooling load for the different cities selected from different climate zones. It is clear that the peak cooling load is 31.59 kW for Delhi (composite climate) whereas the lowest 20.85 kW is for Bangalore (Moderate climate) while annual cooling demand per square meter of building area is highest 225.64 kWhth/m2 for Chennai (Warm and humid). This indicates that the peak cooling load is higher in composite climate (Delhi) and hot and dry climate (Ahmedabad) because the variation of temperature is higher there resulting in the peak
load but the total cooling load is highest for warm and humid climate (Chennai) where the warm and humid climate increases the latent heat load than others resulting in highest cooling demand. Hot and dry climate (Ahmedabad) is the second highest cooling load city because of longer cooling period. Annual Cooling Demand (kWhth/m2) 225.64
250 200 150 100 50
100
194.72 130.85 31.07
20.85
155.92
80 60
28.23
0
40 31.59 20
Peak cooling load kW
5
) LPD(W/ m2) People( Nos.) Equip. Load(W ) Schedul e(Time)
Annual CoolingDemand kWhth/m2
4
0
Fig.3: cooling loads and peak cooling load
Annual
4.2 Solar Fraction It is the ratio of the annual cooling produced by the solar to the total annual cooling demand of the building. Solar Fraction Annual cooling produced by solar absorption chiller = Annual coling demand of building
Fig 4 a-c shows the variation of annual solar fraction with the photovoltaic area for the three types of panel Mono, Poly and Thin film respectively. It is clear from the fig 4 a-c that as the area of photovoltaic panel is increased the annual solar fraction also increases for all type of panels and climate. The annual power generation directly depends on the area of PV panel so any increase in the PV area increases the power generation and more power directly supplied to the cooling system enhances the solar fraction. The highest solar fraction (0.37-0.57) for mono-cells is observed for the hot and dry climate due to higher power generation, and good matching between the cooling load and power generation in the day time. The lowest solar fraction (0.32-0.49) for ISBN-978-81-932091-2-7
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Hot and dry (Ahmedabad) Moderate (Bangalore) Warm and humid (Chennai) Composite (Delhi) Solar Fraction
0.60 0.45 0.30 0.15 0.00 70
80
90
100
110
PV Area m2
(a)
Mono Hot and dry (Ahmedabad) Moderate (Bangalore) Warm and humid (Chennai) Composite (Delhi)
Solar Fraction
0.60 0.45 0.30 0.15 0.00 70
80
90 PV Area
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m2 (b)
Hot and dry (Ahmedabad) Moderate (Bangalore) Warm and humid (Chennai)
0.60
Solar Fraction
mono-cells is observed in the warm and humid climate due to very high cooling load 225 kWhth/m2 and high annual power consumption of 17912 kWhel. For moderate and composite climate, the annual solar fraction ranges between 0.33-0.51, and 0.350.54 respectively. The value of solar fraction for the composite climate is also higher because of the good matching between the power generation and the cooling demand in the summer months. The annual solar fraction is lower for the thin film cells because of the low efficiency of cells for all type of climates. The annual power generation for the poly cell is higher than the thin film but lower than the mono-cell so the annual solar fraction for poly-cell lies between the mono and thin film cells.
0.45 0.30 0.15 0.00 70
80
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100
110
PV Area m2
(c) Thin film Fig.4 a-c Annual solar fraction 4.3 Primary Energy Savings Primary energy consumption is calculated from energy consumption of the cooling systems by dividing it to the conversion factor 0.36 [Eicker et al.]. In the solar photovoltaic cooling system, the electrical consumption is done by the compressor, condenser fan and blower. The primary energy savings is the difference between the primary energy consumption by the solar photovoltaic cooling system and the primary energy consumption by the compression-based cooling system operated by grid power. Fig 5 a-c shows the primary energy savings for the mono, poly and thin film cell respectively. It is clear from the graph that the primary energy savings increase with the PV area for all the climates and type of PV panels. The highest primary energy saving is for the mono cell and lowest for the thin film cells, and for poly cells it is between mono and thin film. The primary energy savings are highest 36%56% for the hot and dry climate and lowest for the warm and humid climate, the reason is same as in the annual solar fraction. The cooling demand is very high for the warm and humid climates and power generation is lesser than hot and dry climates resulting in the low primary energy savings in the warm and humid climates, i.e., 31%-49%. The range of primary energy savings in the moderate climate and composite climate are 35-55% and 34-54 % respectively.
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periods then the payback period is in the range of 4-6 years.
Hot and dry (Ahmedabad) Moderate (Bangalore)
60 Primary Energy Savings(%)
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45
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0 Mono
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Primary Energy Savings(%)
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Fig.6 Payback periods (a) Solar photovoltaic (b) Solar photovoltaic (with net metering)Collector/PV area-90m2
45
70
Poly Type of PV panels
Hot and dry (Ahmedabad) Moderate (Bangalore) Warm and humid (Chennai)
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(c) Thin Fig.5 a-c Primary energy savings 4.4 Payback Periods: Fig 6 a and b shows the payback photovoltaic cooling systems based on the present cost structure in India [see appendix]. It is clear from the graph that the payback is higher. In the solar photovoltaic cooling system, the lowest payback period is observed for the hot and dry climate that is 14.23 years with the thin film cells. If the PV based systems are optimally used with net metering provisions during the non-cooling
5. Conclusions In the solar photovoltaic cooling system, the S.F. is highest for hot and dry climate (Ahmedabad) and lowest for warm and humid climate (Chennai) due to higher cooling demand in Chennai. Primary Energy Savings increases rapidly with the PV area. Solar photovoltaic cooling system (without net metering) has a high payback period. Lowest payback of 14.23 years is found for hot and dry climate (Ahmedabad) due to good combination of cooling demand and annual electricity generation, for moderate climate (Bangalore) payback is highest 34 years. when PV based systems are optimally used with net metering provisions during the non-cooling periods then the payback period is 4-6 years for all climatically zones. In this way this cooling system avoided a large part of CO2 emission. ISBN-978-81-932091-2-7
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hospital” Energy and Building, Vol. 42, pp. 265-272.
6. References 1.
Central Electricity Regulatory Commission New Delhi. 2. Eicker U., Colmenar-Santos A., Teran L., Cotrado M. 2014 “Economic evaluation of solar thermal and photovoltaic cooling systems through simulation in different climatic conditions: An analysis in three different cities in Europe” Energy and Buildings, Vol. 70, pp. 207-223. 3. Eicker U., Pietruschka D. 2009 “Design and performance of solar powered absorption cooling systems in office buildings” Energy and Building, Vol. 41, pp. 81-91. 4. Energy Conservation Building Code (ECBC) User Guide, Bureau of Energy Efficiency (2007). 5. Hartmann N., Glueck C. Schmidt F.P 2011 “Solar cooling for small office buildings: Comparison of solar thermal and photovoltaic option for two different European Climates.” Renewable Energy, Vol. 36, pp. 1329-1338. 6. Henning H.M. 2007 “Solar assisted air conditioning of buildings – an overview” Applied Thermal Engineering, vol. 27 pp. 1734–1749. 7. Kim D.S., Infante Ferreira C.A. 2008 “Solar refrigeration options – a state-of-the-art review” Int. Journal of Refrigeration, Vol. 31, pp. 3–15. 8. Lazzarin R.M. 2014 “Solar cooling: PV or thermal? A thermodynamic and economical analysis” Int.Journal of Refrigeration, Vol.39, pp. 38-47. 9. Mateus T., Oliveira A.C. 2009 “Energy and economic analysis of an integrated solar absorption cooling and heating system in different building types and climates” Applied energy, Vol. 86, pp. 949-957. 10. Tsoutsos T., Aloumpi E., Gkouskos Z., Karagiorgas M. 2010 “Design of a solar absorption cooling system in a Greek ISBN-978-81-932091-2-7
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Effect of Renewable Energy on Green House Effect and Environment : A Study Ravi Prakash Maheshvari, Akhil Nema Civil Engineering Department, Govt. Engineering College Banswara, Raj. (India) Corresponding Author: rpmaheshvari@gmail.com
Abstract Our earth is enclosed by the cover of some gases which retains the heat of rays coming from the sun which increases the the temperature of the earth, this process is called as Green House Effect. This effect increases the temperature and creates some problems like global warming, skin diseases and sea level rise. Renewable energy is basically generated from renewable resources such as wind, rain, tides, waves, sunlight, geothermal that is collected from renewable resources. Renewable energy often provides energy in four important areas electricity generation, air heating and water heating cooling, transportation, and rural energy services. In this study, it is observed that the renewable energy may be a good solution for the harmful and dangerous effects of greenhouse gases. Keywords: Renewable Energy, Green House Effect, Environment, Solar, Wind, Global Warming. The bulk of harmful carbon dioxide emissions appear from combustion of fossil fuels, 1 Introduction In our society the production and consumption of electricity is increasing day by day because it has become the major requirement for us. There are more ways in which we are using that electricity such as television, computers, refrigeration etc. This electric energy is producing by coal, diesel and many renewable sources such as solar, wind, biomass etc. Today fossil fuels are the major input for the production of the electricity which are emitting some harmful agents to the environment like carbon dioxide and methane. Refrigeration and burning of fossil fuels gives chlorofluoro carbon type harmful chemicals to the environment. These harmful chemicals and agents are the main causes of environment degradation and Green House Effect. A greenhouse gas is a agent which emits and An environmental gas which emits and absorbs radiant energy within the thermal infrared range is a greenhouse gas. This creates the greenhouse effect. The primary gases in Earth's atmosphere responsible for greenhouse effect are water vapour, carbon dioxide, methane, nitrous oxide, and ozone. The present average temperature is 150c while it would be -180c without these gases. All the energy generation and consumption processes and human activities has created that the atmospheric concentration of carbon dioxide (CO2), from 280 ppm in 1750 to 406 ppm in early 2017.
primarily coal, oil, and natural gas, with relatively modest supplementary assistance coming from deforestation, changes in land exploit, soil erosion, and farming. If the emissions of green house gases will rise continuously at the present rate then it is estimated that the temperature will increase chronologically till 2047 with dangerous and injurious effects on humans, plants and bio life.
Some researchers studied and said that humans are responsible for global warming and green house effects because deforestation and fossil ISBN-978-81-932091-2-7
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fuel combustion emits the carbon dioxide and other gases which are increasing temperature of environment and magnitude of green house gases, this process is known as Green House Effect. This effect is warming the earth surface and affecting the environment. Major green house gases are carbon dioxide, methane and nitrous oxide. The contribution of green house gases in atmosphere are as follows. Compou Formu nd la Water vapour and clouds Carbon dioxide Methane Ozone
Contribut ion
H20
Concentrat ion in atmospher e (ppm) 10-50,000
Co2
400
9-26%
Ch4 O3
1.8 2.8
4-9% 3-7%
36-72%
When the temperature increases the concentration of greenhouse gases is increase. This increment in temperature is due to combustion of fossil fuels, refrigeration and power generation in power plants. The concentrations of carbon dioxide, methane, and nitrous oxide are all known to be increasing and in recent year, so their greenhouse gases, principally chlorofluorocarbons (CFCs), have been added in significant quantifies to the atmosphere. Noam lior (2008) studied on renewable energy about the present situation and future demand. In that research the work was about the recent estimates and forecasts about the oil, gas and coal resources and their reserve/production ratio, nuclear and renewable energy potential. The work is also consisting of impact of rapidly growing economies of highly populated countries and the effect of global warming is also discussed. The research work concluded that the ways to resolve the problem of the availability, cost and sustainability of energy resources alongside the rapidly rising demand. Joshua M. Pearce (2012) reviewed and analysed the challenges that nuclear power must overcome in order to be considered
sustainable in this paper. This study comprises of the limitations of nuclear energy as a sustainable energy resource. So, this study concluded that if the fossil fuel combustion is replaced by nuclear energy then it is required to improve the technology to reduce greenhouse gas emissions. The technology should improve to diminish the risk in adopting the nuclear energy. The radioactive disposal that is harmful to the environment should be minimise for the duration of mining and other works. The elimination of radioactive disposal that is harmful to the environment should be minimise for the duration of mining and other works. The technology should be improving at that level where the public should have trust on nuclear industry on basis of technologies and financial performance. Bjorn Ulsterman et al. (2007), studied in this work on evaluation of greenhouse gas emissions from organic and conventional systems using carbon cycle model. The work in this paper explain the knowledge about carbon and nitrogen in soil-plant-animalenvironment system. In this research, soil is used for the calculation of carbon, fossil energy is used for the emission of carbon dioxide, farm animals is used for the emission of methane and again soil is used for the emission of nitrus oxide. The specific global warming potential is used in this work for converting the results into carbon dioxide equivalents. Y.S. Mohammed, et al. (2012) has studied in this article and presented that the effect of human made energy generation sources will be dangerous in future because they are emitting the greenhouse gases in large magnitude. This work also gives a considerable information about energy utilization circumstances and intimidating complicated energy context and said that it will become worrying incident worldwide after sometime. Some reduction techniques byy using renewable energy and control measures are also discussed in this article. 2 SOURCES OF GREEN HOUSE GASES There are various greenhouse gases are Water vapor (H20), Carbon dioxide (CO2), Methane (CH4), Nitrous oxide (N20), Ozone (O3), ISBN-978-81-932091-2-7
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Chlorofluorocarbons (CFCs). There are various sources of these greenhouse gases. That are natural systems and human activities, human activities are the energy production, transformation and consumption. The fraction of an emission left behind in the atmosphere after a particular time is the "Airborne Fraction" (AF). The yearly AF is the ratio of the atmospheric rise in a given year to that year's total emissions. The percentage contribution of the greenhouse gases to the greenhouse effect on earth the four major gases are: carbon dioxide 9–26%, methane, 4–9%, water vapour 36–70%, ozone 3–7%. The percentages of annual greenhouse gases are shown in fig.
Annual Green House Gases Emissions INDUSTRIAL TRANSPORTATION
10.3
AGRICULTURE
16.8
POWER PLANTS
11.3 14
10 3.4
21.3
12.5
WASTE DISPOSAL LAND USE AND BIOMASS FOSSIL FUEL RESIDENTIAL AND COMMERCIAL
2.1 Impact of Green House Effect On Environment Global Warming If the greenhouse gases concentration increases then reduction in outgoing infrared radiation occurs, thus the Earth's climate would change this “climatic change” is called as “global warming” of the Earth's surface and the subordinate atmosphere as warming up. Nevertheless, a small increase in temperature will bring many other changes such as cloud cover and wind patterns. Some of these changes may be work to boost the warming. Based on some research the "Intergovernmental Panel on Climate Change" in their third assessment report has forecast that global mean surface temperature will rise by 1.4℃ to 5.8℃ by the end of 2100. This
protrusion takes into explanation the effects of aerosols which tend to cool the climate as well as the delaying effects of the oceans which have a large thermal capacity. Sea Level Rise If global warming occurs, sea level will go up due to two different processes. Firstly, warmer temperature grounds sea level to rise due to the thermal expansion of seawater. Secondly, water from melting glaciers and the ice of Greenland and the Antarctica would also add water to the ocean. It is forecasted that the Earth's common sea level will rise by 0.09 to 0.88 m between 1990 and 2100. Impact on Human Life Over half of the human population lives within 100 kilometres of the sea. Most of this population lives in urban areas that serve as seaports. A measurable rise in sea level will have a severe economic impact on low lying coastal areas and islands, for examples, increasing the beach erosion rates along coastlines, rising sea level displacing fresh groundwater for a substantial distance inland. Experiments have shown that with higher concentrations of CO2, plants can grow bigger and faster. However, the effect of global warming may affect the atmospheric general circulation and thus altering the global precipitation pattern as well as changing the soil moisture contents over various continents. Impact on Aquatic systems Due increment in temperature the wetlands are reduced so the population of marine species are reduced. Nevertheless, the full impact on aquatic species is not known. Impact on Hydrological Cycle Rise in temperature increases evaporation that creates more rainfall. In some regions there is a great rainfall while in few areas there is no rainfall. So, these fluctuations may increase the global precipitation. 3. RENEWABLE ENERGY AND RESOURCES Renewable energy resources are scattered exist in excess of wide geological areas than other energy resources which are intense in few countries. Now a day’s quick consumption of renewable energy resources is necessary because they are renewable. The results of a recent review of the literature concluded that ISBN-978-81-932091-2-7
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as greenhouse gas (GHG) emitters begin to be held liable for damages resulting from GHG emissions resulting in climate change, a high value for liability mitigation would provide powerful incentives for deployment of renewable energy technologies. In worldwide survey of public analysis show that most of the civilian are in support of renewable energy sources. More than 30 countries are using more than 20% of their energy supply as a renewable energy. Two nations that are Norway and Iceland are making their full energy by using renewable energy sources and some other countries are preparing for renewable energy for their energy supply. Earlier to the growth of coal in the middle of the 19th century almost all energy used was renewable. Almost without a doubt the oldest known use of renewable energy in the form of traditional biomass to fuel fires dates from 7,90,000 years ago. Use of biomass for hearth failed to become common place till several many thousands of years later someday between a pair of, 2,00,000 and 4,00,000 years past in all probability the second oldest tradition of renewable energy is harnessing the wind so as to steer ships higher than water. In past time the human labour, animal power, water power and wind were the renewable resources. Renewable energy resources may be some natural resources like that Sun's electromagnetic radiation, tides or heat generation inside the Earth. Following are the main renewable energy resources: Solar energy the radiation of the sun is captured in solar panels that are exposed to sunlight. The sunlight can be changed into electrical energy to power all the appliances in a home. It can also be used to heat a house and to create hot water. There are also some drawbacks in solar energy system that they consume some more space for their arrangement and the collection of energy completely depends upon whether conditions. Wind power it is energy derived from the movement of the wind. The most recognizable example of wind power is the windmill, which is using for crushing the grain. This principle is also using in generation of electricity using turbine that is known as wind
turbine. Wind is a very hygienic resource of energy, but it requires large space and occasionally noisy blades to work. Biomass energy when the plant material and animal excreta is burnt then there was the emission of biomass energy. Biomass comes from freshly livelihood organisms, not the old materials that form fossil fuels. Geothermal energy The Earth's interior is extremely hot—hot enough to melt the rock that comes out of a volcano in the form of lava. That heat creates hot water and steam below the Earth's surface, which can be harnessed by digging a well. As the steam or water rises, it can be used to run a turbine and create electricity. Hydropower is energy captured from the movement of water. It is sometimes called hydroelectric power because the water is used to turn turbines that create electricity. The hydropower energy is a fresh and fine source of energy that creates about no pollution but it may cause changes to the surrounding atmosphere that can influence animals and plants.
3.1 Advantages of Renewable Energy 1. First main advantage of renewable energy is that it is renewable it is therefore durable and so it will never run out. 2. Renewable energy services normally need not as much of maintenance than conventional power generators. Their fuel being brought from natural and available resources that reduces the expenditure of action. 3. Even more importantly, renewable energy produces little or no waste products such as carbon dioxide or other chemical ISBN-978-81-932091-2-7
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pollutants, so has minimal impact on the environment. 4. Renewable energy projects can also bring economic benefits to many regional areas, as most projects are located away from large urban centres and suburbs of the capital cities. 3.2 Disadvantages of Renewable Energy 5. First main drawback of renewable energy that it is not easy to produce the energy in bulk as great as those generated by conventional fossil fuel generators. Because the consumption is more than the production in our society. For proper maintenance there should be a perfect balance in various sources of energy. 6. Another difficulty in renewable energy resources is that this energy depends on whether conditions. For example, flowing water is required to operate the hydro generators and wind is required to operate the wind turbines. The present cost of renewable energy is more than conventional energy generators. 7. The production of renewable energy is required more space and for collection it requires the particular location that means if we want to take more benefits of renewable energy we have to construct a whole arrangement of network. And these arrangements of network require burning the fossil fuels that ultimately emits the greenhouse gases. ROLE OF RENEWABLE ENERGY IN REDUCTION OF GREEN HOUSE GASES AND CONTROL MEASURES 1. No Damage to Environment while Extracting Major energy resources used for power generation are extracted from the core of the planet. This includes oil, gas, or coal. large amounts of those resources square measure extracted, and it wants a lot of exploitation of the mother Earth. This results in increase in expenses due to constant drilling. This lead to the discharge of hepatotoxic gases into the atmosphere that becomes damaging for nature additionally as humans. However,
on the opposite hand, the renewable-energy sources square measure simply obtained, and that they don't unleash any harmful gases. 2. Reduction in Carbon Emission If we use the conventional energy resources the carbon dioxide emission increases in the environment. On the other hand, if we use the renewable sources for energy the emission of carbon dioxide drastically reduces. The renewable energy is nearby in great quantity only wants right technology and infrastructure. Some researchers said that conventional power generation resources emit nearly 40% of the carbon dioxide. Which is destructive to the atmosphere. 3. Helps in reducing Global Warming The renewable-energy resources facilitate for reducing the global warming as it reduces the quantity of greenhouse gases emission to the environment that is major contributing factor to it. The renewable energy sources will help in eliminating the emission of poisonous gases. 4. Sustaining the Renewable-Energy Sources It is very important to keep up the renewableenergy resources because these are facilitating in generating the fresh and clean energy which is very important and useful for the environment now a day. For this, the government ought to expect to the correct infrastructure and technological improvement which will facilitate them to sustain for longer. Moreover, the property can facilitate in handling several environmental problems regarding fuel depletion, emission of dioxide and alternative threatening problem s. 5. Decreases the Adverse Environmental Impacts The renewable energy is a clean type of energy on the other hand another conventional type of resources is giving the harmful and injurious environment. So, we should have to go for renewable energy because by using this energy we can keep our country green and clean. The world is growing on daily basis more and more so the individual requires the utilization of the electricity at residence or industrialized establishments. So, it is the best time to about turn from conventional resources to the ISBN-978-81-932091-2-7
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renewable resources feel the clean and green environment. 8. CONCLUSION This research study concluded that energy production, transformation and consumption are the main reasons of greenhouse gases emission and global warming that are very harmful and adverse to human life. This study has also shown that the energy production, transformation and consumption are the major source of greenhouse gas emission actually and human actions are the minor sources. It is clear from this work that these gases and agents are very harmful to us so application of renewable energy is the best option for reducing the effects of these harmful agents to the environment. Ultimately, it is required to increase the uses of renewable energy utilization to solve the problems of energy safety, energy loss and health related issues. The earth is enclosed by a cover of gases, which allows the energy from the sun to reach the earth’s surface and temperate it. The majority of the heat is reflected back to space but some part of gases is retained by the atmosphere that increases the temperature of the earth so the gases which retain the heat in atmosphere is called as greenhouse gases and this effect is known as greenhouse effect. So, this increment in temperature results some problems to environment such as global warming, melting of ice and sea level rise etc. By using the renewable energy like solar, wind, biomass and hydropower etc. we can reduce the effect of greenhouse problems and can give the healthy and joyful environment to the coming generation. 9. 1.
2.
REFERENCES Pooja T. Latake, Pooja Pawar, Anil C Ranveer, 2015, “The Greenhouse Effect and Its Impacts on Environment”, International Journal of Innovative Research and Creative Technology, IJIRCT, ISSN: 2454-5988, (2015)/ IJIRCT1201068. Bjorn Kustermann, Maximilian Kainz, Kurt-Jurgen Hulsbergen, 2007, “Modeling carbon cycles and estimation of greenhouse gas emissions from
3.
4.
5.
6.
7.
8. 9. 10.
organic and conventional farming systems’’, Renewable Agriculture and Food Systems: 23(1); 38–52, 30 july 2007. Noam Lior, 2008, “Energy Resources and Use: The Present Situation and Possible Paths to The Future, Journal of Energy, Elsevier Publication, Energy 33, 842-857, doi:10.1016/j.energy.2007.09.009. Joshua M. Pearce,2012, “Limitations of Nuclear Power as a Sustainable Energy Source”, Journal of Sustainability, ISSN 2071-1050, 4, 1173-1187; doi:10.3390/su4061173. Y.S. Mohammed, A.S. Mokhtar, N. Bashir, U.U. Abdullahi, S.J. Kaku, U. Umar, 2012, “A Synopsis on the Effects of Anthropogenic Greenhouse Gases Emissions from Power Generation and Energy Consumption” , International Journal of Scientific and Research Publications, ISSN 2250-3153,1-7, 10, October, 2012. Scott Canonico, Royston Sellman, Chris Preist, 2009 “Reducing the Greenhouse Gas Emissions of Commercial Print with Digital Technologies,” International Symposium on Sustainable Systems and Technology (ISSST),1-8. Arman Shehabi, Ben Walker and Eric Masanet, 2014,“The energy and greenhouse-gas implications of internet video streaming in the United States”, Environ. Res, 1-11. WWW. History of greenhouse gases, (http://en.wikipedia.org/wiki/Greenhous e_gas) Greenhouse effect –Wikipedia.com. Renewable energy – Wikipedia.com.
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Fault Ride-Through Techniques of Wind Turbine State of Art: A Review Manish kumawat, Aditya Prakash Dixit Department of Electrical Engineering, Govt. Engineering College Banswara, Raj. (India) Corresponding Author: mkumawat813@gmail.com
Abstract Today, renewable sources for the generation of electricity is becoming more popular due to depleting fossil fuels. Solar and wind energy is the world’s fastest growing source of renewable energy also grid integration of wind power is growing in leaps and bounds and India is one of them. The cost of producing one kilowatt hour of electrical energy from the wind power is the cheapest. All this has become possible because of recent developments in electrical, mechanical, power electronics, materials and other fields which have wide range of applications in renewable energy technology. Wind power, at the one end is very much useful source of energy same time when it is connected to the electric grid creates some quality issues like voltage sag, swell, harmonics etc. Wind power plants are much affected by faults which occur in each and every power plant. In this article a comparative study has been carried out for different fault ride-through techniques. Keywords: Renewable Energy, Fault ride-Through Technique, Crowbar, Blade-pitch angle control, STATCOM
1.
Introduction
The Renewable energy is a form of energy which is obtained from naturally from tides, wave, sunlight, wind, ocean and geothermal heat. It is used in following important areas such as generation of electricity, heating and cooling of water and air, transportation, and rural (off-grid) energy services. Renewable energy sources exist around the world, in discriminate to other energy sources, which are situated in a limited number of areas. Rapid expand and utilization of renewable energy may reduce the rate of climate change and affect the world in economic measure. 1.1 Renewable energy in India India is a vast country. Its energy requirement is increasing day by day and depleting coal make to switch towards renewables. Based on Renewable Energy Policy Network of 21 century (REN21's) 2017 report, renewables contributed 17.7% to total Indian energy consumption. Renewable sources for electricity are targeted to increase heavily by 2022 this
includes more than doubling of large wind power capacity. These large targets, if achieved timely, would place India amongst the world leaders in renewable energy sector. Overall installed capacity of India is 329.4 GW and renewables contribute 57.472 GW as of 14 June 2017. Contribution of wind and solar is nearly 61% and 19% respectively. MNRE has sets its targets to produce renewable electricity from 43 GW in April 2016 to 175 GW by 2022. This includes 100 GW from solar power, 60 GW from wind power. These ambitious targets would make India one of the leading green energy producers and surpassing many developed countries in the world. Wind power generation capacity in India has significantly increased in recent years making total installed capacity of 32.72 GW (October 2017). This is the fourth largest installed wind power capacity in the world. Due to increment of wind power the tariff of wind power has dipped a record low of ₹2.64 (4.1¢ US) per kWh (without any subsidies) during the auctions for wind power ISBN-978-81-932091-2-7
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projects in October 2017. Before that the tariff was Rs.3.42/kWh in August 2017. Following tables shows the Fuel wise Generation Installed Capacity in India and Installed capacity of renewable energy source in India. Table 1.1 Fuel wise Generation Installed Capacity in India Fuel
Installed (MW)
THERMAL Coal Gas Diesel HYDRO NUCLEAR RES TOTAL
219,490 193,467 25,185 838 44,653 6,780 58,303 329,226
Capacity % Share Total
in
66.7% 58.8% 7.6% 0.3% 13.6% 2.1% 17.7%
National Power Training Institute (N.R.)Badarpur, New Delhi -110044) Table 1.2 Installed capacity of renewable energy source (31 August 2017) Energy source
Power(GW)
Percentage
Wind energy
32GW
56%
Solar energy
13GW
22%
Biomass energy
8GW
14%
Small hydro energy
4GW
8%
National Power Training Institute (N.R.) Badarpur, New Delhi -110044) 1.2 Issues Associated with Wind Energy The wind penetration levels in India has increased dramatically in the recent years. This increase, affect the performance of the power system due to its integration and operation. A moderate share does not create any problem. Increasing capacity may create many problems therefore new regulations for grid connection of WPPs become necessary for stability of power system. These new regulation creates issues which are: 1) Interface issue and 2) Operational issue. Interface issues are short circuit power control, active and reactive power control and
voltage control. The operational issues are Power system stability, frequency control, short and long term balancing, impact on transmission and distribution and economic dispatch. Power system stability affects by the faults occurring in the system and seeks more attention. Different faults occurring in power system also affects grid stability where the penetration of wind power is large. Hence transmission and distribution operators decided to form new grid codes addressing these issues. Thus, it was required to analyze fault ride through behavior of DFIG wind turbine under the influence of new grid code. Modern largescale wind turbines, typically 1 MW and larger, are normally required to include systems that allow them to operate through such an event, and thereby “ride through” the voltage dip. Depending on the application the device may, during and after the dip, be required to: Disconnected temporarily from the grid and but reconnect and continue operation after the dip, stay disconnected until manually reconnected stay operational and not disconnect from the grid and support the grid with reactive power (Fault Ride-Through) 2. Fault ride through Fault ride through (FRT) is the capability of WT generators to stay connected in the network for short periods of lower voltage (voltage dip). It is needed at distribution level to prevent a short circuit which causes loss of generation. Some critical loads such as computer systems and industrial processes are handled by an uninterruptible power supply (UPS) or capacitor bank to supply make-up power during interruption of supply in a similar manner. 2.1 Fault Ride-Through Requirement of Wind Turbine Systems Expanding wind power creates some new problems to power system. The power system with large scale wind power will involve problems in steady state operation and in contingency condition. FRT keep the WTs to stay connected to grid during faults so that ISBN-978-81-932091-2-7
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stability to the power transmission system is maintained. The most common fault in the power system is voltage drop and its lowest depth can be zero. The stator of DFIG is directly connected to the grid, while its threephase rotor windings are coupled to the grid through a back-to-back converter. Very high rotor current may lead to the damage of rotor side converter and the DC bus over-voltage. During the fault, a large fault current flows through the stator of DFIG because it is directly connected to the grid. Since the rotor and stator are magnetically coupled and the flux is conservative this disturbance must affect the rotor of DFIG making the rotor current very high and an overcurrent may flow through the rotor side converter. Owing to this WTs must have capability to support voltage by providing reactive power to the grid and this is done riding-through the fault. Following figure shows the voltage supporting capability of WTs.
capability to maintain the reactive power balance and the power factor in the desired range.
3.
Strategies
FRT approaches can be divided into two main categories: 1. Passive Methods these methods use additional equipment: such as crowbar methods, energy capacitor system (ECS) and energy storage system (ESS), blade pitch angle control. 2. Active Methods These methods use appropriate converter control. 1. Passive methods A) Blade pitch angle control: It is one of the most widely used techniques to regulate the output power of a wind turbine. This method is based on the variation in the input power to the turbine as the pitch angle of the blades is changed. Pitch angle of blade is varied by hydraulic actuators. B) Crowbar methods: This is the classical method to fulfill FRT requirements. It has ability to protect the generator and the converter as well during the faults. Dangerous effects of fault are minimized by crowbar protections systems. Crowbar avoid the disconnection of the doubly fed induction wind generators from the network during faults.
Fig 1.1 variation of voltage in FRT (http://energyprofessionalsymposium.com/img/ 1237/image023_2.jpg New grid codes ensures that during FRT following conditions must meet. During a voltage drop, turbines remain connected for specific time duration before being allowed to disconnect. Wind power plants must regulate their active power output to ensure a stable frequency in the system and reactive power
Fig 2.1 Crowbar [9] Faults at terminal of DFIG induced the high current and increased the DC-link voltage of the converter, to protect from this severe condition crowbar protection system is used. ISBN-978-81-932091-2-7
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Conventional crowbar, series crowbar and a new protection method named the outer crowbar are main types of crowbar system. In conventional crowbar technique, when a short circuit occurred the RSC is disabled and bypassed, at the same time external resistors are coupled via the slip rings of the rotor windings in place of the converter. The series crowbar, three resistors which are parallel with bidirectional static switches are connected in series with stator winding. During short circuit at the DFIG terminals these switches are triggered otherwise switches are not triggered. Outer crowbar is quite similar to series crowbar but difference in series crowbar and series outer crowbar is that the outer crow bar is connected in series with the DFIG instead of the stator winding. C) Energy capacitor system: This method is similar to some extent to crowbar configuration, except that this method protects the converter from overvoltage and can dissipate energy without effecting the rotor currents.
Fig 2.2 Energy capacitor (https://ars.elscdn.com/content/image/1-s2.0S0378779613002174 gr1.jpg) D) Energy storage system: This method controls the generator during the fault. The battery stores energy in the electrochemical
form, and is the most widely used for energy storage in a variety of application.
Fig 2.3 Energy storage (https://ars.elscdn.com/content/image/1-s2.0S0960148116302981-gr15.jpg) 2. Active Methods It is a combination between hardware modifications (e.g., crowbar) and control strategies. A feed-forward transient current control scheme is used for the rotor side converter (RSC) of a DFIG with crowbar protection. Another method uses a parallel grid side rectifier (PGSR) with a series grid side converter (SGSC). All these methods require additional devices which leads to extra costs and increases system complexity. So, it would be better to eliminate these devices. With these considerations, the implementation of classical flux-oriented vector control techniques (PI controllers) has been proven to work well to fulfill the grid code requirements. But, this kind of control could be easily saturated when dealing with substantial sag and it is sensitive to the generator parameters and other phenomena such as disturbances and unmodeled dynamics. These above classical control techniques suffers from the drawback that is their linear nature due to which robustness is lacking. A robust nonlinear controller based on the sliding mode, an LVRT scheme for a PMSGbased WT based on the feedback linearization theory and a susceptance control strategy are ISBN-978-81-932091-2-7
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some non- linear control strategies are also proposed for FRT of wind turbines. 3. New approaches STATCOM and DVR are the new devices to provide FRT of WTs. Static synchronous compensator (STATCOM) is a Flexible AC Transmission Systems (FACTS) device. It is a power electronic based synchronous var compensator that generates three-phase reactive power in synchronism with the transmission line voltage. It is connected to it by a coupling transformer. STATCOM consist of a three-phase inverter using Gate Turn-off Thyristors. It acts as a sink or a source of reactive power (inductor/capacitor). By varying the amplitude of the converter voltage with respect to the system bus voltage, STATCOM can continuously exchange power through the flow of a controlled current. The power exchange between STATCOM and rest of the system is purely reactive although an insignificant amount of active power is supplied by the grid to compensate for converter losses. This reactive power support enables the STATCOM improve the voltage profile of the system and reduce voltage fluctuation in event of grid disturbance. Dynamic Voltage Restorer (DVR) is a series connected device, which corrects the voltage dip and restore the load voltage in case of a voltage dip. Basic DVR topology is illustrated in Fig 3.1. Dynamic Voltage Restorer (DVR) is applied to compensate for voltage sags and swells and expected to respond fast (less than 1/4 cycle) and thus employs PWM converters using IGBT devices.
Figure 3.1 Basic DVR Topology
4. Comparison Faults are the severe problem faced by wind turbines connected to grid. Due to fault in the system power is lost so fault ride-through provides the alternative power to distribution network. So many FRT techniques are proposed for this. All the methods of FRT have some advantages and disadvantages associated with them. Passive methods are easy to implement, cost effective, have best controllability of active and reactive power also improve voltage profile. They also suffers some disadvantages like large response time and have reduced peak generating capacity, also absorbs large amount of reactive power from the grid this will degrade the grid voltage. In some methods additional energy storing elements are required which further increases the cost of the system. Due to additional cost and complexity in passive methods, active methods using PI controller are proposed. These methods saturated easily when they deal with sags. Some linear controllers are also there but they are not robust. Besides this some new techniques are under development and testing. These are STSTCOM and DVR method. They provide active and reactive power to the system during fault when it is required during faults.
5.
Conclusion
LVRT is found to be the biggest challenge facing by wind turbine farms; in particular those using DFIGs. This type of generator is very sensitive to grid disturbance, in particular voltage sags. To overcome this sensitivity, several FRT techniques have been proposed. These strategies have been examined and advantages and disadvantages of each one have been discussed. The use of additional hardware can be avoided if the rotor-side converter is able to counter the grid disturbance effects. Therefore, particular attention has been drawn to nonlinear control strategies. Some new techniques are also developed in recent years. FRT techniques are very costly and industries ISBN-978-81-932091-2-7
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doesn’t disclose their researches due to competitive market. Therefore, future researches should be focused on the development of DFIG robust and cheaper strategies for the solution of FRT problem. Reference 1. Marwa Ezzat, Mohamed Benbouzid, Sm Muyeen, Lennart Harnefors. Low-Voltage Ride-Through Techniques for DFIG-Based Wind Turbines: State-of-the-Art Review and Future Trends. IEEE IECON 2013, Nov 2013, Vienne, Austria. pp.7681-7686, 2013. 2. Xinyan Zhang1, Xuan Cao2, Weiqing Wang1, Chao Yun1 Fault Ride-Through Study of Wind Turbines Journal of Power and Energy Engineering, 2013, 1, 25-29 3. Supercapacitor energy storage system for fault ride-through of a DFIG wind generation system A.H.M.A. Rahim a,⇑, E.P. Nowicki b a Department of Electrical Engineering, King Fahd University of Petroleum & Minerals, Dhahran, Saudi Arabiab Department of Electrica & Computer Engineering, University of Calgary, Calgary, AB,Canada 4. Ms.Ch.laxmi, Ms.K.Sree Latha, 3Dr.Himani 1Asst.prof(EEE) GNITC,Hyderabad 2Assoc.Prof(EEE) GNITC, Hyderabad 3Prof & HOD(EEE) Aurora’s Engg ,Bhongir Improving the low voltage ride through capability of wind generator system using crowbar and Battery Energy storage system. International Journal of Engineering Science Invention ISSN (Online): 2319 – 6734, ISSN (Print): 2319 – 6726 5. Supercapacitor energy storage based-UPQC to enhance ride-through capability of wind turbine generators Gangatharan SIVASANKAR, Velu SURESH KUMAR Department of Electrical and Electronics Engineering, Thiagarajar College of Engineering, Madurai, India, Turk J Elec Eng & Comp Sci (2015) 23: 1867 { 1881 6. Montazeri, Miad Mohaghegh, "Improved Low Voltage Ride Through Capability of Wind
Farm using STATCOM" (2011). Theses and dissertations. Paper 1407. 7.C. Jauch, P. Sorensen, I. Norheim and C. Rasmussen, “Simulation of the Impact of Wind Power on the Tran- sient Fault Behavior of the Nordic Power System,” Elec- tric Power System Research, Vol. 77, 2007, pp. 135-144. 8.S. J. Hu, J. L. Li and H. H. Xu, “Analysis on the Low- Voltage-Ride-Through Capability of Direct-Drive Perma- nent Magnetic Generator Wind Turbines,” Automation of Electric Power Systems, Vol. 31, No. 17, 2007, pp. 73-77. 9.https://www.researchgate.net/profile/Sadegh_ Ghani_Varzaneh/publication/281627313/figure/ fig1/AS:287010901250058@1445440139828/F igure-1-Schematic-diagram-for-DFIGaccompanied-with-conventional-crowbarprotection.png. 10. Meegahapola LG, Littler T, Flynn D. Decoupled-DFIG fault ride-throughstrategy for enhanced stability performance during grid faults. IEEE Trans Sustain Energy 2010;1:152– 62. 11. Ahsanul Alam M, Rahim AHMA, Abido MA. Supercapacitor based energy storage system for effective eault ride through of wind generation system. In:IEEE international symposium on industrial electronics (ISIE2010), Bari, Italy July, 2010. 12. X. Dawei, R. Li, P. J. Tavner, and S. Yang, "Control of a doubly fed induction generator in a wind turbine during grid fault ride-through," IEEE Transactions on Energy Conversion, vol. 21, pp. 652-662, 2006. 13. E. Koutroulis, D. Kolokotsa, and G. Stravrakakis,"Optimal design and economic evaluation of a batteryenergy storage system for the maximization of the energygenerated by wind farms in isolated electric grids," WindEngineering, vol. 33, pp. 55-81, 2009. 14. V. Akhmatov, “Analysis of dynamic behavior of electric power system with large amount of wind turbine”, Ph.D. thesis, Orsted DTU, pp. 26–28,30, 31, 2003. 15. S. M. Muyeen, R. Takahashi, T. Murata, and J. Tamura, “Integration of an energy ISBN-978-81-932091-2-7
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capacitor system with a variablespeed wind generator,” IEEE Trans. Energy Convers., vol. 24, no. 3, pp. 740-749, Sep. 2009. 16. K. H. Kim, Y. C. Jeung, D. C. Lee, and H. G. Kim, “LVRT scheme of PMSG wind power systems based on feedback linearization,” IEEE Trans. Power Electron., vol. 27, no. 5, pp. 2376-2384, May 2012. 17. D. W. Xiang, S. C. Yang and L. Ran, “Magnet Excitation Control Strategy of DFIG on Grid Operation during Power System Symmetric Fault,” Proceedings of the CSEE, Vol. 26, No. 3, 2006, pp. 164-169. 18. D. Campos-Gaona, E. Moreno-Goytia and O. Anaya-Lara, “Fault Ride-Through Improvement of DFIG-WT by Inte- grating a Two-Degrees-of-Freedom Internal Model Control,” IEEE Transactions on Industrial Electronics, Vol. 60, No. 3, 2013, pp. 11331145. 19. F. Díaz-González, A. Sumper, O. GomisBellmunt and R. Villafáfila- Robles, “A review of energy storage technologies for wind power applications,” Renewable and Sustainable Energy Reviews, vol. 16, n°4,pp. 2154-2171, May 2012. 20. D. Ramirez, S. Martinez, C. Carrero and C.A. Platero, “Improvements in the grid connection of renewable generators with full power converters,”Renewable Energy, vol. 43, pp. 90-100, July 2012.
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Numerical solution to Natural convection in Triangular enclosures and its application for double dome solar water distillation systems Nagesh Babu Balama, Akhilesh Guptab, Ashok Kumara, B.M Sumana a CSIR-Central Building Research Institute, Roorkee, India b Indian Institute of Technology, Roorkee, India
Abstract: Natural convection flow is numerically estimated in triangular domain using finite difference method. Natural convection flow in triangular domain enclosures is a common phenomenon observed in a variety of applications such as double dome type solar water distillation units, building roof top cross-section (attic space), solar collectors and in many other engineering applications. Convection flow is analyzed by varying the Rayleigh number (Ra) from 103 to 106 and the aspect ratio from 0.2 to 1.0 with bottom surface heated and inclined surfaces cooled simultaneously. The fluid inside the domain is air having Prandtl no (Pr) = 0.7. The results are presented in stream line and temperature contours. Bipartisan, counter rotating triangular and symmetric stream line contours are observed within the domain for lower values of Ra. As â&#x20AC;&#x2DC;Raâ&#x20AC;&#x2122; value is increased the stream line contours exhibit unsymmetrical behavior with one major contour and counter rotating minor contours. The present study provides more physical insight into the natural convection in triangular domain applications and also provide a mechanism to control the heat transfer by varying aspect ratio at the design stage. Keywords: Natural convection, Finite Difference method, Vorticity, Streamfunction, Triangular Domain. Nomenclature: Ar Aspect Ratio (H/L) β Thermal expansion coefficienct Gr Grashoff number Îľ Numerical tolerance limit H Height of enclosure θ Non dimensional temperature L Length of enclosure ν Kinematic viscosity n Time step Ď density Pr Prandtl number Ď&#x201E; Non dimensional time Ra Rayeligh number Ď&#x2C6; Stream function t time Ď&#x2030; vorticity T Temperature Îł Angle of inclination Subscripts đ?&#x2018;˘â&#x192;&#x2014; Velocity vector u,v Vel. components in x & y directions h hot x,y Transverse and normal coordinates c cold Îą Thermal diffusivity I,j X and Y coordinate indices 1. Introduction: Natural convection in triangular enclosures is a very common phenomena observed in variety of applications such as double dome type solar water distillation units, building roof top crosssection (attic space), solar collectors and in many other engineering applications. A comprehensive review of natural convection in triangular enclosures is carried out by kamiyo et al [1] and das et al [2] and Saha et al[3]. Natural
convection in isosceles triangular domain is studied by many researchers due to its variety of applications. Holtzman et al [4] has carried out experimental and numerical laminar natural convection studies in isosceles triangular enclosures with a heated horizontal base and cooled upper walls. The problem is examined over aspect ratios ranging from 0.2 to 1.0 and Grashof number (Gr) from 103 to 105. ISBN-978-81-932091-2-7
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Pitchfork bifurcation is observed at critical Gr above which the symmetric solutions are unstable to finite perturbations and asymmetric solutions are instead obtained. Basak et al. [5] used finite element method to simulate the natural convection in isosceles triangular enclosures due to uniform and non-uniform heating at the side walls. The numerical solution of the problem is presented for various Rayleigh numbers (Ra), (103 < Ra < 106) and Prandtl numbers (Pr), (0:026 < Pr < 1000). It has been found that at small Prandtl numbers, geometry does not have much influence on flow structure while at Pr = 1000, the stream function contours are nearly triangular showing that geometry has considerable effect on the flow pattern. In addition, the presence of multiple circulations are observed for small Pr = 0.026 which causes wavy distribution of local Nusselt number. It is observed that non-uniform heating produces greater heat transfer rates at the center of the walls than the uniform heating; however, average Nusselt numbers show overall lower heat transfer rates for the non-uniform heating case. Taher et al[6] used Lattice Boltzamann method (LBM) for simulating similar problem and studied the effect of varying the Ra and Aspect ratio. Saha et al [7] has studied the Natural convection in a triangular enclosure heated from below and non-uniformly cooled from top. The numerical simulations of the unsteady flows over a range of Rayleigh numbers and aspect ratios are carried out using Finite Volume Method. Since the upper inclined surfaces are linearly cooled and the bottom surface is heated, the flow is potentially unstable. It is revealed from the numerical simulations that the transient flow development in the enclosure can be classified into three distinct stages; an early stage, a transitional stage, and a steady stage. The flow inside the enclosure depends significantly on the governing parameters, Rayleigh number and aspect ratio. The effect of Rayleigh number and aspect ratio on the flow development and heat transfer rate are discussed. The key finding for
this study is to analyze the pitchfork bifurcation of the flow about the geometric center line. The overall studies are found to be in good agreement and have been able to consistently predict the natural convection flow in triangular domain. Similar studies were conducted for non-isosceles and inclined triangular domains. Mahmoudi et al. [8] conducted Numerical Study of Natural Convection in an right-angled triangular enclosures for Different Thermal Boundary Conditions using Lattice Boltzmann method. Numerical results are obtained for a wide range of parameters: the Rayleigh number spanning the range (103 - 106) and the inclination angle varying in the intervals (0° to 120°) and (0° to 360°) for two cases adiabatic vertical walls and inclined isothermal walls. It is observed that inclination angle can be used as a relevant parameter to control heat transfer in right-angled triangular enclosures. Solar distillation in double dome and single dome structures are well studied using double diffusive convection in triangular enclosures. Omri et al [9] has studied the Natural convection effects in solar stills. The aim of the study is to examine the thermal exchange by natural convection and effects of buoyancy forces on flow structure. The study provides useful informations on the flow structure sensitivity to the governing parameters, the Rayleigh number and the tilt angle, on the thermal exchange. In a basin still receiving a uniform heat flux, the results show that the bottom is not isotherm and the flow structure is sensitive to the cover tilt angle. Many recirculation zones can occur in the core of the cavity and the heat transfer is dependent on the flow structure. The results of this study can provide information for the enhancement of the design of the energy systems such as solar water distillers and air conditioning systems. Rahman et al [10] has studied the Double-diffusive natural convection in a triangular solar collector. Effects of the thermal Rayleigh number and buoyancy ratio are presented by streamlines, isotherms, ISBN-978-81-932091-2-7
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isoconcentration as well as local and mean heat and mass transfer rates for the aforesaid parameters. Effects of the thermal Rayleigh number and buoyancy ratio are presented by streamlines, isotherms, isoconcentration as well as local and mean heat and mass transfer rates for the aforesaid parameters. Varol et al. [11] has conducted study on Natural convection in triangular enclosures with protruding isothermal heater. Governing parameters, which are effective on flow field and temperature distribution, are; Rayleigh number, aspect ratio of triangle enclosure, dimensionless height of heater, dimensionless location of heater and dimensionless width of heater. Streamlines, isotherms, velocity profiles, local and mean Nusselt numbers are presented. It is found that all parameters related with geometrical dimensions of the heater are effective on temperature distribution, flow field and heat transfer. In the present study, Convection flow is analyzed by varying the Rayleigh number (Ra) from 103 to 106 and the aspect ratio (base length/height) from 0.2 to 1.0 with bottom surface heated and inclined surfaces cooled simultaneously. The fluid inside the domain is air having Prandtl no (Pr) = 0.7. The results are presented in stream line and temperature contours. 2. Problem Formulation
Figure1: The triangular domain model Consider a 2D triangular domain of base length â&#x20AC;&#x2DC;2lâ&#x20AC;&#x2122; and height â&#x20AC;&#x2DC;Hâ&#x20AC;&#x2122; as shown in Fig. 1. The cavity is filled with air and its bottom and inclined walls are maintained at â&#x20AC;&#x2DC;θhâ&#x20AC;&#x2122; and â&#x20AC;&#x2DC;θcâ&#x20AC;&#x2122;, respectively. Boundary conditions for a triangular enclosure is shown in figure [1]. A 2D Laminar Natural Convection flow is assumed inside the cavity. Boussinesq approximation is assumed for the gravity term in the momentum equation. The flow is governed by the following set of equations. Conservation of Mass đ?&#x153;&#x2022;đ?&#x2018;˘ đ?&#x153;&#x2022;đ?&#x2018;Ł + =0 đ?&#x153;&#x2022;đ?&#x2018;Ľ đ?&#x153;&#x2022;đ?&#x2018;Ś Conservation of X-directional Momentum with Boussinesq approximation đ?&#x153;&#x2022;đ?&#x2018;˘ đ?&#x153;&#x2022;đ?&#x2018;˘ đ?&#x153;&#x2022;đ?&#x2018;˘ +đ?&#x2018;˘ +đ?&#x2018;Ł đ?&#x153;&#x2022;đ?&#x2018;Ą đ?&#x153;&#x2022;đ?&#x2018;Ľ đ?&#x153;&#x2022;đ?&#x2018;Ś 1 đ?&#x153;&#x2022;đ?&#x2018;? đ?&#x153;&#x2022; đ?&#x2018;˘ đ?&#x153;&#x2022; đ?&#x2018;˘ = â&#x2C6;&#x2019; +đ?&#x153;? + đ?&#x153;&#x152; đ?&#x153;&#x2022;đ?&#x2018;Ľ đ?&#x153;&#x2022;đ?&#x2018;Ľ đ?&#x153;&#x2022;đ?&#x2018;Ś â&#x2C6;&#x2019; đ?&#x2018;&#x201D;đ?&#x203A;˝ (đ?&#x2018;&#x2021; â&#x2C6;&#x2019; đ?&#x2018;&#x2021; )đ?&#x2018; đ?&#x2018;&#x2013;đ?&#x2018;&#x203A;đ?&#x203A;ž Conservation of Y-directional Momentum with Boussinesq approximation đ?&#x153;&#x2022;đ?&#x2018;Ł đ?&#x153;&#x2022;đ?&#x2018;Ł đ?&#x153;&#x2022;đ?&#x2018;Ł +đ?&#x2018;˘ +đ?&#x2018;Ł đ?&#x153;&#x2022;đ?&#x2018;Ą đ?&#x153;&#x2022;đ?&#x2018;Ľ đ?&#x153;&#x2022;đ?&#x2018;Ś 1 đ?&#x153;&#x2022;đ?&#x2018;? đ?&#x153;&#x2022; đ?&#x2018;Ł đ?&#x153;&#x2022; đ?&#x2018;Ł = â&#x2C6;&#x2019; +đ?&#x153;? + đ?&#x153;&#x152; đ?&#x153;&#x2022;đ?&#x2018;Ś đ?&#x153;&#x2022;đ?&#x2018;Ľ đ?&#x153;&#x2022;đ?&#x2018;Ś + đ?&#x2018;&#x201D;đ?&#x203A;˝ (đ?&#x2018;&#x2021; â&#x2C6;&#x2019; đ?&#x2018;&#x2021; )đ?&#x2018;?đ?&#x2018;&#x153;đ?&#x2018; đ?&#x203A;ž Conservation of Energy đ?&#x153;&#x2022;đ?&#x2018;&#x2021; đ?&#x153;&#x2022;đ?&#x2018;&#x2021; đ?&#x153;&#x2022;đ?&#x2018;&#x2021; đ?&#x153;&#x2022; đ?&#x2018;&#x2021; đ?&#x153;&#x2022; đ?&#x2018;&#x2021; +đ?&#x2018;˘ +đ?&#x2018;Ł = đ?&#x203A;ź + đ?&#x153;&#x2022;đ?&#x2018;Ą đ?&#x153;&#x2022;đ?&#x2018;Ľ đ?&#x153;&#x2022;đ?&#x2018;Ś đ?&#x153;&#x2022;đ?&#x2018;Ľ đ?&#x153;&#x2022;đ?&#x2018;Ś Average Nusselt Number 1 đ?&#x153;&#x2022;đ?&#x2018;&#x2021; đ?&#x2018; đ?&#x2018;˘ = â&#x2C6;&#x2019; đ?&#x2018;&#x2018;đ?&#x2018;Ś đ??ż đ?&#x153;&#x2022;đ?&#x2018;Ľ Grashoff Number: Gr = Ra X Pr Boundary conditions for a triangular domain are as follows đ?&#x2018;Ľ = đ?&#x2018;Ľ, đ?&#x2018;Ś = 0: đ?&#x2018;˘ = 0, đ?&#x2018;Ł = 0, đ?&#x2018;&#x2021; = đ?&#x2018;&#x2021; đ?&#x2018;Ľ = đ?&#x2018;Ľ, đ?&#x2018;Ś = đ?&#x2018;Ľ: đ?&#x2018;˘ = 0, đ?&#x2018;Ł = 0, đ?&#x2018;&#x2021; = đ?&#x2018;&#x2021; â&#x2C6;&#x20AC; (đ?&#x2018;Ľ â&#x2030;¤ đ?&#x2018;&#x2122;) đ?&#x2018;Ľ = đ?&#x2018;Ľ, đ?&#x2018;Ś = (2đ?&#x2018;&#x2122; â&#x2C6;&#x2019; đ?&#x2018;Ľ), đ?&#x2018;˘ = 0, đ?&#x2018;Ł = 0, đ?&#x2018;&#x2021; = đ?&#x2018;&#x2021; â&#x2C6;&#x20AC;( đ?&#x2018;Ľ > đ?&#x2018;&#x2122;) ISBN-978-81-932091-2-7
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2.
Numerical Method
The governing equations are solved in a 2D triangular domain. Vorticity-Stream function formulation is used for solving the Governing equations. Obtained Partial differential equations for Stream function, vorticity and Temperature are converted to Algebraic equations using Finite difference method. Staircase approximation is used to solve the finite difference method applied to nonrectangular geometry. 1st order Upwind scheme is used for discretization of convective terms. 2nd order Central difference scheme is used for discretization of diffusion terms. 2nd Order Alternate Direction Implicit (ADI) scheme is used to discretize the transient term. The obtained coefficient matrices are in implicit line Tri-diagonal form and are solved using Thomas algorithm. The numerical computations are carried out for 154X77 grid nodal points for a time step of 10-4. The convergence criteria required that the absolute difference between the current and previous iterations for all of the dependent variable be less than 10-5. Grid Independence test is carried out and found 154X77 grid density gives satisfactory performance for the present study. The average Nusselt number is calculated at the bottom surface. 4.Results The results obtained for triangular domain are compared with Holtzman et al.[4]. for the Average Convective Nusselt number parameter. This parameter is defined as given below. Table [1] shows the comparision of Nuc for various Aspect ratios in the range of 0.2 to 1.0. and for Grashoff Number in the range of 103 to 105 . Figure [2] shows the comparision of local convective Nusselt number ( Nuc ) along the Symmetric plane of Isosceles triangular domain for Ar = 0.5, Gr = 105
Average Convective Nusselt Number Nuc :
1 2 Ar Nuc ( X )dX 2 Ar 0 where Convective Nusselt Number is the ratio of Nusselt number at given Gr to Nusselt number evaluated for corresponding conduction solution I.e Gr = 0 given by Nuc Gr Nuc Gr and Nu c ; Nuc Gr 0 Y Y 0 H Ar for triangular domain shown in figure [] L Nu c
Grid Independence study: The governing equations are solved in a 2D triangular domain. The numerical computations are carried out for 154X77 grid nodal points for a time step of 10-4. The convergence criteria required that the absolute difference between the current and previous iterations for all of the dependent variable be less than 10-5. Grid Independence test is carried out for various grid sizes from 101X51, 154X77, 201X101 and found that 154X77 grid density gives satisfactory performance for the present study. Table1 : Comparision of Average Convective Nusselt Number, with holtzman et al.: Aspect Gr = Gr = Gr = Ratio 103 104 105 Holtzman 1.0 1.0 1.07 1.80 et al. Present 0.996 1.08 1.85 Study Holtzman 0.5 1.0 1.20 2.19 et al. Present 0.99 1.20 2.20 Study Holtzman 0.2 1.0 1.28 2.48 et al. Present 0.998 1.29 2.45 Study ISBN-978-81-932091-2-7
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Figure 3: Natural convection flow Isotherms with Aspect ratio:1.0, Ra = 103
Figure 4: Natural convection flow Streamlines with Aspect ratio:1.0, Ra = 103 Figure 2 : Comparision of local convective Nusselt number with Holtzman et al. The non-dimensional streamline and temperature contours are shown in the following figures [3 - 10] by varying the Rayleigh number from Ra = 103 to 105 . The effect of changing the angle of inclination of inclined walls is observed in figure [9-10] for Ra = 106 and inclination angle of inclined walls = 30°.
Figure 5: Natural convection flow Isotherms with Aspect ratio:1.0, Ra = 104
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Figure 6: Natural convection flow Streamlines with Aspect ratio:1.0, Ra = 104
Figure 9: Isotherms for Ra = 106 and angle of inclination = 30°. Figure 7: Natural convection flow Isotherms with Aspect ratio:1.0, Ra = 105
Figure 10: Streamline and Isotherms for Ra = 106 and angle of inclination = 30°. Figure 8: Natural convection flow Streamlines with Aspect ratio:1.0, Ra = 105
Conclusions: This paper presents a method for solving viscous incompressible Navier-stokes equations in vorticity stream-function formulation and its application to natural convection flow in triangular domain. Convection flow is analyzed by varying the Rayleigh number (Ra) from 103 to 106 and the aspect ratio from 0.2 to 1.0 with bottom surface heated and inclined surfaces cooled simultaneously. Such configuration is commonly encountered in solar water distillation systems of double dome type. ISBN-978-81-932091-2-7
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The results are presented in stream line and temperature contours. At low temperature difference between bottom wall and inclined walls the heat raises at the symmetric plane at center of triangular domain and cools near the inclined walls and thus completing a rotating contours which are symmetric in nature. Bipartisan, counter rotating triangular and symmetric stream line contours are observed within the domain for lower values of Ra. As ‘Ra’ value is increased the stream line contours exhibit unsymmetrical behavior with one major contour and counter rotating minor contours.
5.
6.
7. The developed method estimates the Natural convection flow behaviour in triangular domain. The present study can be applied for optimizing the design of Solar water distillation systems. 8. References: 1. O.M. Kamiyo, D. Angeli, G.S. Barozzi, M.W. Collins, V.O.S. Olunloyo, S.O. Talabi,A comprehensive review of natural convection in triangular enclosures, Appl. Mech. Rev. 63 (2010) 06080. 2. D. Das et al., Studies on natural convection within enclosures of various (non-square) shapes – A review, Int. J. Heat Mass Transfer (2016), http://dx.doi.org/10.1016/j.ijheatmasstran sfer.2016.08.034 3. S.C. Saha, M.M.K. Khan, A review of natural convection and heat transfer in attic-shaped space, Energy Build. 43 (2011) 2564–2571. 4. G.A. Holtzman, R.W. Hill, K.S. Ball, Laminar natural convection in isosceles triangular enclosures heated from bellow and symmetrically cooled from above,
9.
10.
11.
Journal of Heat Transfer 122 (2000) 485– 491. T. Basak, S. Roy, Ch. Thirumalesha, Finite element analysis of natural convection in a triangular enclosure: effects of various thermal boundary conditions, Chemical Engineering Science 62 (2007) 2623– 2640. M. A. Taher, Y. W. Lee, and H. D. Kim, LBM Simulation on Natural Convection Flow in a Triangular Enclosure of Green House under Winter Day Conditions, Journal of Engineering Thermophysics, 2016, Vol. 25, No. 3, pp. 411–423 Suvash C. Saha , Y.T. Gu, “Natural convection in a triangular enclosure heated from below and non-uniformly cooled from top”, International Journal of Heat and Mass Transfer 80 (2015) 529–538 Ahmed Mahmoudi, Imen Mejri, Mohamed Ammar Abbassi, and Ahmed Omri, “Numerical Study of Natural Convection in an Inclined Triangular Cavity for Different Thermal Boundary Conditions: Application of the Lattice Boltzmann Method”, FDMP, vol.9, no.4, pp.353-388, 2013 Ahmed Omri, Jamel Orfi, Sassi Ben Nasrallah, “Natural convection effects in solar stills”, Desalination 183 (2005) 173– 178 M.M. Rahman , Hakan F. Öztop A. Ahsan, M.A. Kalam, Y. Varol, “Doublediffusive natural convection in a triangular solar collector”, International Communications in Heat and Mass Transfer 39 (2012) 264–269 Y. Varol, H.F. Oztop, T. Yilmaz, Natural convection in triangular enclosures with protruding isothermal heater, International Journal of Heat Mass Transfer 50 (2007) 2451–2462.
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Concept Paper on
Solar Parks to Ramp up Solar Projects in the Country, Issues and Challenges: Contribution towards Climate Change Radhey Shyam Meena1, Swati Agariya2, Prof. D. K. Palwaliya3, Dr. Shivlal4, Dr. Nitin Gupta5, A. S. Parira6 , S K Gupta7 1,6,7Ministry of New & Renewable Energy, New Delhi, India 110003 2National Institute of Solar Energy, Gurugram, India 122005 3,4Government Engineering College Banswara, India 327001 5Malaviya National Institute of Technology, Jaipur, India 302017 Abstract The objective of this paper is to review the basic concepts of solar parks and its new era of development of solar projects in India. The paper describes the most recent approach for development of solar projects in the form of a solar park with growth oriented and easily acceptable facilities to all. Considering the declining prices of solar power vis-a-vis other source of costlier power, leading to growth in solar sector by which it has become more affordable to Solar Project Developers (SPDs) and Distribution Companies (DISCOMs). In solar parks an increased trend in participation in bidding, as they foresee opportunities in solar business with reasonable return on investment. Further, the increased scalability, assured off-take, guaranteed payment, risk free and preserving grid connectivity also created an environment of profitable business. With a strong commitment to increase the renewable sources-based energy capacity to 175 GW by 2022, India has a target to install 100 GW of solar energy capacity out of which 40 GW would be the share of Solar Parks. The another approach in this chapter is to evaluate the determined policy in India on large scale ultramega solar projects or solar parks which designed as a package deal, enabling project development time lines to be streamlined by allowing different government as well as private agencies to undertake land acquisition and seek necessary permits, and providing a dedicated common infrastructure in the form of developed land, water availability and access roads, and power transmission systems for setting up solar power generation plants inside the solar park. Key words: Solar Parks, Renewable Energy in India, National Solar Mission, Solar Development 17) as Phase-II and the 13th Plan (2017-22) as 1. Introduction Phase-II. Policy framework under Mission is to National Solar Mission (NSM) is a major create the necessary environment to attract initiative by Government of India, to promote industry and project developers to invest in ecologically sustainable growth and research, domestic manufacturing and addressing energy security challenge. The development of solar power generation and NSM is one of the eight missions of National thus create the critical mass for a domestic Action Plan on Climate Change (NAPCC). solar industry. Recognizing the potential of solar energy to The mission National Solar Mission (NSM) contribute to energy security of the country, under the brand name “Solar India” set an the Government of India launched NSM on the target of adding 20 GW of Grid connected and 11th January, 2010. The objective of the NSM 2 GW of Off-grid capacity by 2022. is to establish India as a global leader in solar India, in its Intended Nationally Determined energy, by creating the policy conditions for its Contributions (INDC), announced to increase diffusion across the country as quickly as share of installed electric power capacity from possible. Implementation of the Mission is non-fossil-fuel-based energy resources by envisaged to adopt a 3-phase approach, 2030 to 40% and to reduce the emission spanning the period of the 11th Plan and first intensity of its GDP from 33 to 35% by 2030. th year of the 12 Plan (up to 2012-13) as PhaseIn consideration of above, the Government of I, the remaining 4 years of the 12th Plan (2013India in June 2015 scaled up the target for ISBN-978-81-932091-2-7
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15 to 2016-17 as on 31.03.2017), as compared to 11,746 MW installations during preceding three years (2011-12 to 2013-14). 40000.00 32746.87 30000.00 20000.00
15747.81 8181.70 4399.35 863.92 114.08
10000.00 0.00
1 Wind Power Solar Power- Ground Mounted BioPower Small Hydro Power Solar Power- Roof Top Waste to Power
Figure 1: Installed Capacity of Renewable Energy in India as on 30-11-2017 (Source: MNRE/CEA)
5502 5526
The cumulative installed capacity of grid renewable power has reached to 57,244 MW at the end of FY 2016-17, which accounts for 17% of grid renewable power installed capacity from all resources. The aggregate 57,244 MW grid renewable power installed capacity includes 32,280 MW from Wind power, 12,289 MW from Solar power, 4380 MW from Small Hydro Power and 8295 MW from Bio-Power as shown in the figure 2. 6000
185 106
305 219
1000
2312
2079
1112 296 252
2000
946 790 171
3000
1700
4000
3423 3019
5000
656 627 237
Installed Capacity (MW)
setting up of grid connected solar power capacity from 20,000 MW to 1,00,000 MW by 2022 under the NSM. The above capacity is proposed to be achieved through deployment of 40,000 MW of rooftop solar projects and 60,000 MW medium& large scale solar projects. In order to harness the solar potential efficiently and to achieve the objectives of NSM, it was required to develop State level Infrastructure solely dedicated to promote solar power generation. One of the ways of achieving that was development of solar parks in a focused manner across different parts of the country. The solar park is a large chunk of contagious land developed with all necessary infrastructures like approach & access road, water facility, power evacuation infrastructure, metrological station, telecommunication infrastructure etc. Solar Park also facilitates developers by reducing the number of required approvals. The most important benefit from the solar park for the private developer is the significant time saved. The solar parks facilitate the solar project developers to set up projects in a plug and play model. 2. Solar Energy Status in India: India’s Power Sector has predominantly been based on fossil power and use mostly domestically produced coal to generate electricity. The country has been rapidly adding generating capacity since Independence largely due to economic growth, rising population, rapid urbanization leading to rise in demand. The utility electricity sector in India has one National Grid with an installed capacity of 330.86 GW as on November, 2017. India is the world's third largest producer and fourth largest consumer of electricity. The gross electricity consumption was 1,122 kWh per capita in the year 2016-17. The per capita electricity consumption is low compared to many countries despite cheaper electricity tariff in India. The contribution of power from renewable energy sources contributes about 17% and that of solar power is more than 4% in the overall energy mix as shown in figure1. The growth of around 90% has been achieved with capacity addition of 22,256 MW grid renewable power during last three years (2014-
0 2012-13 2013-14 2014-15 2015-16 2016-17 Wind Power Solar Power Bio Power Small Hydro
Figure 2: RE sectors wise progress during last 5 years However, the main challenges being faced in conventional power generation include depleting coal reserves in India, difficulty in procurement of imported coal and long gestation periods of coal-based power plants. ISBN-978-81-932091-2-7
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India, with its large population and rapidly growing economy, needs access to clean, cheap and reliable sources of energy. India lies in the high solar insolation region, endowed with huge solar energy potential with most of the country having about 300 days of sunshine per year with the daily solar radiation incident varies from 4 - 6 kWh per square meter of surface area depending upon the location and time of the year. Government of India has taken up renewable energy as an article of faith and set up an ambitious target of 175 GW installed renewable capacity by 2022. Out of 1,75,000 MW, 1,00,000 MW is proposed to be achieved through solar energy. As on October 2017, around 14,800 MW solar power projects have been installed in the country. The Government is promoting solar energy through fiscal and promotional incentives, such as capital subsidy, generation-based incentive, accelerated depreciation, viability gap funding (VGF), financing solar rooftop systems as part of home loan, concessional custom duty, exemption from excise duty and foreign direct investment up to 100 per cent under the automatic route, etc. There is tremendous opportunity for foreign investment in India in solar sector as foreign direct investment is permitted under the automatic route. Reserve Bank of India (RBI) has announced renewables including solar energy as priority sector. This will enable banks to provide loans up to a limit of Rs 150 million to borrower companies of renewable energy. For individual households, the loan limit has been set to Rs 1 million per borrower. Ministry of Finance has accorded in-principle approval for issuance of tax free infrastructure bond of Rs. 5000 crore for funding renewable energy projects. India has taken another initiative to create an International Solar Alliance (ISA). It will be a group of around 120 countries working for development and promotion of solar energy. India as founder member of this alliance has offered to have its secretariat and also committed some financial contribution. 3. Growth of Solar Capacity Prior to the launch of National Solar Mission, only 11 MW of solar capacity was installed.
However, after the launch of the NSM and other State policies encouraging solar energy generation, the solar capacity grew at a rapid pace. Total solar capacity installed of about 1 GW was added upto the 11th Plan Period and about 9 GW were added in 12th Plan Period. In last five years, solar energy sector has grown at a rapid pace. As shown in figure 3 the installed capacity of solar projects has increased from 2,632 MW in 2013-14 to 16,675 MW in 2017-18 . 16675 12288 6763
3
11
36
2632 1030 1686
3744
Figure 3: Cumulative Installed capacity (in MW as on 30-11-2017, Source: MNRE/CEA) Out of the above solar capacity, the 10 states contribute about 90% of the total capacity installed as shown in figure 4. 3500.00 2990.07 3000.00 2310.46 2165.21 2500.00 1819.42 1800.85 2000.00 1500.00 1000.00 500.00
1304.11 1184.86 876.80 521.88 509.38
0.00
Figure 4: Top ten states in Solar Capacity (in MW) 4. Solar Manufacturing in India One of the NSMâ&#x20AC;&#x2122;s objectives is to take global leadership role in solar manufacturing across the value chain of leading edge solar technologies and target a 4-5 GW equivalent installed capacity by 2020. The Mission statement mentions setting up of dedicated polysilicon manufacturing capacities sufficient to cater to produce 2 GW worth of solar cells annually. In India, most manufacturing capacity was idle or operating at low utilisation rates, primarily ISBN-978-81-932091-2-7
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because it is uncompetitive due to lack of scale, low-cost financing, and underdeveloped supply chains. Solar manufacturing in India started after the announcement of the NSM. The present cell and module manufacturing capacities in India are given below: Module Cell 10000 7746.44
6817.12 2.5
6000 4000
2731
2689
2000
1.75 1.5
Module 2500
2257.19135 3
2000 1500 1000 743.275 500 171.383 2013-14
682.57 332.839 2014-15
0.59
0.52
0.48
0.34
2017-18
2016-17
2015-16
0
Module Cost…
Figure 7: Declining Module Cost 5. Trend of Solar Tariff Calculation of tariff depends on various factors that include location, solar irradiance in the State, availability of conducive State policy for solar, availability of land, the cost of financing and business environment, willingness of DISCOMS to purchase the solar power, power evacuation infrastructure, etc. 18
960.962
0.6
0.5
20
1418.161
1
2014-15
Figure 5: Installed and Operation Capacity of Solar Module & Solar Cell In respect of installed and operation capacity in India, actual production capacity is quite low as shown in figure 6 that in year 2013 production of module & cell was 743 MW & 171 MW respectively and now in 2016-17 the production is around 2257 MW & 682 MW respectvily.
1
2013-14
Operational capacity
2012-13
Installed capacity
2011-12
0
0
2.2
2
2010-11
8000
tariff is Rs. 5.68 per kWh. The cost of PV modules have since continuously been reducing over the period with advancement of technology as well as with significant improvement in global supply scenario. In view of the falling cost of PV modules, the tariff of solar PV projects have also been declining significantly as in the graphically representation of figure 8 below.
17.91
16 14
420.687
12 2015-16
2016-17
Figure 6: Year wise production of Solar Module and Solar Cell The solar projects under Phase-1 of National Solar Mission were set up during the period 2010-11 to 2011-12. For the period 2010-11, CERC determined the project cost of solar PV projects as Rs.16.90 Cr. / MW based on the prevalent PV module prices (US$ 2.2/Wp) and the corresponding tariff as Rs.17.91 per kWh. The project cost determined by CERC for the period 2016-17 is Rs. 5.30 Cr./MW based on the PV modules prices of US$0.48/Wp. Declining module cost year wise is as shown in the figure 7.The corresponding solar PV
10 8 6 4
7
6.45
6.47
6.17 4.34
3.30
2.44
2 0
Figure 8: Year-wise lowest solar tariff (in Rs. /kWh) Pursuant to successful bidding of solar projects under NSM, the solar projects which are being set up under the State Scheme are mostly selected through a process of tariff based competitive bidding and reverse auction. This ISBN-978-81-932091-2-7
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method of selection has brought down the solar average bid tariff discovered in bidding/auctions significantly from a level of Rs. 17.91 per kWh in December, 2010 to about Rs.2.97 per kWh in February, 2017. Tariff in Indian solar market changed regularly as shown in Figures that the weighted average tariff varies from Rs. 17.91 per unit to Rs. 2.44 per unit. The declining trend of solar power tariff during the period from 2010-11 to 201718 is shown below in figure 8 below: The recent downward trends in solar tariff may be attributed to the factors such as economies of scale, assured availability of land, and power evacuation systems under the solar parks. 6. Concept of solar Park The concept of solar park was conceived from Charanka Solar Park in Gujarat, and closely followed by the Bhadla Phase-I Solar Park in Rajasthan. Solar power projects can be set up anywhere in the country. To set up solar projects, a solar project developer is required to identify and acquire the required land along with all necessary statutory clearances required from the concerned Government, arrange other infrastructure facilities like approach road, water, telecommunication facility etc., develop transmission infrastructure for evacuation of solar power to the nearest grid substation. The above process is required to be followed by every solar project developer for setting up solar projects. It generally takes a longer time for project developers to acquire land, get change of land use and various permissions, etc. which delays the project. The solar projects scattered in multiple locations lead to higher project cost per MW and higher transmission losses. Total cost of a solar project depends on multiple factors such as solar insolation at a particular site, infrastructure facilities required to be developed, logistics, cost of funding, prevailing prices of solar cells/modules and related policies of the Government. Solar Parks can be instrumental in overcoming the bottlenecks otherwise faced by independent power producers in a solar PV plant, related to land availability, developing evacuation infrastructure and its funding and
other financial challenges. To overcome these challenges, the scheme for Development of Solar Parks has been introduced in December, 2014. A solar park is large contiguous stretch of land with high insolation levels and provides developers an area that is well characterized with proper infrastructure and access to amenities and where the risk of the projects can be minimized. A solar park facilitates assured availability of land and transmission infrastructure facilities for setting up higher capacity of solar projects, reducing the number of approvals required, minimizing time of setting up solar projects thereby provide both economy of scale for cost-reduction and achieving large scale reduction in GHG emissions. The solar parks provide specialized services to incentivize solar project developers to invest in solar projects in the park. These services while not being unique to the park, are provided in a central, one-stop-shop, single window format, making it easier for investors to implement their projects within the park in a significantly shorter period of time, as compared to projects outside the park which would have to obtain these services individually. In addition, the park provides road access (both approach roads and smaller access roads to individual plots), water (via a dedicated reservoir located within the premises), boundary fence and security, each of which would have entailed additional costs for the developer outside the park. Each of these specialized services offer significant benefits to the project developers but come at a premium. Land plots within the solar park are more expensive than outside. But this premium is easily justifiable by these services, which are bundled into the land cost. However, the most important benefit from the park for the project developer is the significant time saved. The centralized, single window nature of the services within the park reduces the time between project conceptualization and operations, translating into economic and real monetary gains for the project developers and the State. The capacity of the solar park has been kept at 500 MW and above level in order to achieve ISBN-978-81-932091-2-7
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economy of scale for cost-reduction. However, smaller parks can also be set up in hilly areas where contiguous land may be difficult to acquire in view of the difficult terrain and where there is acute shortage of nonagricultural lands. A systemic representation of the concept of the solar park is given in figure
transmission line to connect with the existing network is therefore, required to be set up either by CTU or STU. Setting up of substation nearby the solar park and creation of transmission line to connect with the existing network of CTU/STU is termed as external power evacuation system. 7. Operational Structure: The State Governments willing to set up solar parks first identify an agency for development of solar park. The agency entrusted with the responsibility of setting up of solar park is termed as Solar Power Park Developer (SPPD). A State Government may select SPPD in any of the following four modes: Modes for selection of SPPD
Figure 9: Systemic representation solar park The solar park is divided into several plots based on the topography & availability of the land and suitability of power evacuation arrangement. Here in above figure, P1, P2 & P3 are the individual plots and A1, A2…B6 are solar projects inside the plots of the solar park. The power generated from the individual projects pooled to a nearby pooling station. For this each plot is interconnected with pooling stations through 33kV/other suitable voltage underground, over ground or overhead cable. The construction of this line from the solar projects up to the pooling station is the reponsibity of the Solar Project Developers (SPDs). The Solar Power Park Developer (SPPD) is responsible to set up, internal transmission system to evacuate the power from the solar park. The internal transmission system consists of setting up of the pooling stations (with 33/220 kV or suitable voltage level) inside the solar park and will also draw transmission line to transmit power from pooling station to the nearest sub-station of Central Transmission Utility (CTU) or State Transmission Utility (STU) at 220 KV/400 KV or suitable voltage level. The solar power from the solar park needs to be evacuated to the existing grid. A gridsubstation (220 KV/400 KV or suitable voltage level) right adjacent to the solar park and
Mode I
The State designated nodal agency, could be a State Government Public Sector Undertaking (PSU) or a Special Pu rpose Vehicle (SPV) of the State Govern ment.
A Joint Venture Company between the State designated nodal agency and SECI with 50: 50 % equity.
Mode III
Mode II
The State designates SECI as the nodal ag ency on behalf of State Government on m utually agreed terms.
Private entrepreneurs without any equity particip ation from SECI, but may have equity participati on from the State Government or its agencies.
Mode I V
The SPPD is tasked with acquiring the land for the park, cleaning it, leveling it and allocating the plots for individual projects. Apart from this, the SPPD are also entrusted with providing the necessary facilities like approved land for installation of solar projects and required permissions including change of land use etc; road connectivity to each plot of land; water availability for construction as well as running of power plants; flood mitigation measures like flood discharge, internal drainage etc; power during construction; centralized weather monitoring station; telecommunication facilities; power evacuation facility consisting of pooling stations to allow connection of individual solar projects with pooling station through a ISBN-978-81-932091-2-7
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network of underground/over ground cables or overhead lines; housing facility for basic manpower wherever possible; parking, warehouse etc. 8. Progress and Status The Scheme for Development of Solar Parks was rolled out in December, 2014 by Government of India. It was planned to set up at least 25 solar parks, each with a capacity of 500 MW and above, thereby targeting around 20, 000 MW of solar power installed capacity; in a span of 5 years commencing from 201415. Smaller parks are also allowed in Himalayan region & other hilly States where contiguous land is difficult to acquire in view of difficult terrain and in States where there is acute shortage of non-agricultural land. Considering the demands for more solar parks in States, the capacity of the solar park scheme is enhanced from 20,000 MW to 40,000 MW in March, 2017. All these solar parks are proposed to be set up by 2019-20. As on October 2017, 35 solar parks with cumulative capacity of 20,503 MW have been approved in 21 States as shown in figure 10 these solar parks are in different stage of development. In addition to the above recently 500 MW solar park approved for Tamil Nadu by TNEB Ltd.
have been acquired for 9 solar parks namely Radhnesada solar park in Gujarat, Bhadla PhII, Bhadla-III Solar Park & Bhadla IV solar parks in Rajasthan, Ananthapur-II & Kurnool solar parks in Andhra Pradesh and solar parks in Meghalaya, Uttarakhand and Uttar Pradesh. Further more than 90% of required land have been acquired in five solar parks namely Ananthapur-I & Kadapa solar parks in Andhra Pradesh, Pavagada solar park in Karnataka, Rewa solar park in MP, Aamguri solar park in Assam as shown in the figure 12. Power Purchase Agreement (PPAs) have been signed for around 4545 MW of solar projects inside various solar parks; out of which 2230 MW of have been commissioned. Further, tenders for additional 2500 MW have been issued for which PPAs are yet to be signed. Solar Projects inside the five solar parks have already been commissioned as shown in the figure 11.
1600
1500
Total Capacity (MW)
Capacity Commissioned (MW)
1400 1200
1000 1000
1000 800
680680 500
600 400 200
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200 50
0
Figure 11: Solar projects commissioned inside various solar parks
Figure 10: Solar Parks in India The land of around 1,11,000 acres have been identified & 66,000 acres of land have been acquired in various solar parks. 100% land
9. Remarkable Case Studies Kurnool Solar Park (1000 MW) in Andhra Pradesh: The Kurnool Solar Park of capacity 1000 MW has already been commissioned and is operational since March, 2017. Around 240 MU of clean energy is generated from this park till end of May resulting in savings of 2.1 Lakh tones of CO2 emissions. ISBN-978-81-932091-2-7
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(a)
(b)
(c)
(d) Figure 13 Kurnool Solar Park in AP (a) Kurnool Solar Park (1000 MW commissioned) (b) Anantpuramu Phase –I solar park (250 MW commissioned) (c) Pooling substation of NP Kunta site and Kurnool site and (d) ground level water reservoir with rain water harvesting at Kurnool With commissioning of 1000 MW capacity at single location, Kurnool Solar Park has emerged as the World’s Largest Solar Park after Longyangxia Dam Solar Park of capacity 850 MW in China which was commissioned in the year 2016. Pavagada Solar Park (2000 MW) in Karnataka: The Pavagada Solar Park in Karnataka (2,000 MW), would be the largest solar park of it’s kind after Tengger Desert Solar Park of capacity 1500 MW in Zhongwei, Ningxia of China which is under construction and also known as the “Great Wall of Solar” in China. Pavagada Solar Park in Karnataka has the potential to be the largest solar park in the world once completed. Here, 200 MW solar photovoltaic projects along with 15 minutes energy storage facility through battery for peak smoothening is also proposed to be set up by Solar Energy Corporation of India (SECI). Rewa Solar Park (750) in Madhya Pradesh: Rewa Solar Park in Madhya Pradesh brought a revaluation in tariff of solar power in Indian market by achieving the lowest ever levelized tariff of Rs. 3.30/kWh through competitive bidding of 750 MW. The tariff so discovered depends inter alia on multiple factors like the long-term and concessional debt from World ISBN-978-81-932091-2-7
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Bank, three level payment security mechanism through Letter of Credit, Payment Security Fund, State Guarantee, power purchase tied directly with end procurers like Madhya Pradesh Power Management Corporation Ltd. (MPPMCL) and Delhi Metro Railway Corporation (DMRC) etc.The tariff of Rewa Project is not unviable; rather it is low on account of its better project structure, bankability, balanced risk allocation, preidentified available land, the readiness of internal and external evaluation structure, and a soft loan from the World Bank. The projects (three units each of 250 MW) were awarded to the three successful bidders. The tariff of Rs. 2.97, Rs. 2.974, and Rs. 2.979 per kWh discovered for the three 250 MW units each of Rewa park is the first-year tariff with 5 paise per year increase for 15 years. The levelized tariff for 25 years of Rewa Solar Park projects would be around Rs. 3.30/kWh. Kadapa Solar Park (1000 MW) in Andhra Pradesh: The Kadapa Solar Park in Andhra Pradesh (1,000 MW) being developed by APSPCL has also set a new record after the success of Rewa Solar Park as the tariff discovered for 250 MW project is Rs. 3.15 a unit. Bhadla Phase IV Solar Park (500 MW) in Rajasthan: In Bhadla Phase-IV Solar Park at Bhadla, Jodhpur, Rajasthan being developed by JVC of State Government of Rajasthan and M/s Adani Renewable, the lowest tariff discovered is Rs. 2.62 per unit for 250 MW by SECI under the VGF scheme.
Figure 14: 680 MW Solar Park Bhadla Ph-II in Rajasthan
Bhadla Phase III Solar Park (1000 MW) in Rajasthan: The Bhadla Phase III Solar Park in Rajasthan is being developed by a JVC of State Government of Rajasthan and IL&FS. SECI invited the bids for 500 MW solar projects inside Bhadla-III solar park and the lowest tariff discovered for 200 MW is Rs. 2.44 per unit followed by Rs. 2.46 per unit for 300 MW under the VGF scheme. 10. Issues & Challenges The concept of solar parks has indeed emerged as a powerful tool for the rapid development of solar power projects in India. Assured availability of land and transmission infrastructure are the major benefits of a solar park. The recent downward trends in solar tariff may be attributed to the factors like economies of scale, assured availability of land and power evacuation systems under solar park. The Solar Park Scheme aims to provide a huge impetus to solar energy generation by acting as a flagship demonstration facility to encourage project developers and investors, prompting additional projects of similar nature, triggering economies of scale for cost-reductions, technical improvements and achieving large scale reductions in GHG emissions. It would enable States to bring in significant investment from project developers, meet its Solar Renewable Purchase Obligation (RPO) mandate and provide employment opportunities to local population. However, the development of solar parks has various issues and challenges as given below: (i) Land: Land is a very critical input for development of solar park. The requirement of land is approximately 4-5 acres for the setting up of solar parks. Land for the setting up of solar park is generally identified by the State/UT Government unless the SPPD has its own land. It is the responsibility of the State Government to help in making the land available if the SPPD selected by the State Government needs help. States are encouraged to identify sites receiving good solar radiation and sites which are closer to CTU, preferably locations with spare transmission capacities and water availability. However, private entrepreneurs selected by the State ISBN-978-81-932091-2-7
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Government as SPPD are allowed arrange their own land for setting up the solar park. Land are generally taken on long term lease from Government as well as private sources. In such cases, the State Governments are required to ensure that the land is free from any dispute. The park provides opportunity for all technologies in a technologically agnostic fashion. In order to provide for such a large tract of contiguous land with appropriate insolation levels, the state governments are advised to prioritize the use of government waste / nonagricultural land in order to speed up the acquisition process. The inexpensive land are preferred in order to keep the land cost as low as possible and attract the developers. The land owned by the State Government is given priority and efforts are made to acquire private land as minimum as possible. If land cannot be made available in one location, then land in few locations in close vicinity are also taken. The acquisition of land for solar park is one of the biggest challenges. Various state governments have announced favorable land policies that have been instrumental in reducing this hassle. Some of the cases of acquisition of land are hereunder: In Rajasthan, the State Government under its Solar Policy, 2016 has announced availability of land to the developers at lowest cost. There are six solar parks in Rajasthan and in all the cases; the State Government has made the required land available to the park developers. Most of the lands allotted for solar parks are Government land and there was no land conversion charge whereas the stump duty was 5-6% of the value of the land. In Andhra Pradesh, there are four solar parks being developed by AP Solar Power Corporation Pvt. Ltd. (APSPCL), a joint venture company of Solar Energy Corporation India (SECI), Andhra Pradesh Power Generation Corporation (APGENCO) and New & Renewable Energy Development Corporation of Andhra Pradesh Ltd. (NREDCAP). In all the cases, the park developer tried to select government land. However, there are also assigned and patta land. A negotiation committee comprising of local revenue authorities is constituted by the
government of Andhra Pradesh for direct negotiation with farmers to finalise the compensation payable to different categories of land to enable speedy acquisition of land. For acquisition of government land, assigned land and patta land following process is being followed in Andhra Pradesh as shown in the figure 16.
Figure 16: Land acquisition process in Andhra Pradesh APSPCL, the Solar Power Park Developer in Andhra Pradesh is facing various issues in acquisition of land for the solar parks. APSPCL has selected the land, maximum of which belongs to the State Government. The State Government usually assigns certain Government lands to land less poor by giving assignment. The Government can take back these assigned lands for its own use by paying suitable compensation on par with the patta lands. Before paying compensation to these assigned lands, the revenue department calls land owners/farmers for original assignment and other relevant records for verification. The issue arises when the farmers fail to submit the records for claiming compensation. The revenue department denies compensation to these farmers who fail to submit he records. These farmers regularly come to site and stop the works. Further while granting assignment to land less poor, the Government stipulates condition to the farmers to bring the land in to the cultivation within three years. If the farmers donâ&#x20AC;&#x2122;t bring the land into cultivation within ISBN-978-81-932091-2-7
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three years, the assignment granted to the farmers will be cancelled and the farmer is not eligible for any compensation. These types of farmers also come to site and stop the works. Some of the farmers approach court seeking compensation for these types of lands. Some farmers deny claiming compensation and want to retain his assigned land for his livelihood. In some cases, it is not possible to delete this land from acquisition if the land is in the middle of acquired land. In such cases the farmers approach courts and comes to site and stops the works. In Karnataka, 2000 MW solar park is being developed by Karnataka Solar Power Development Corporation Ltd. (KSPDCL); a joint venture company of Karnataka Renewable Energy Development Ltd. (KREDL) & SECI. The uniqueness in land acquisition for the Pavagada solar park in Karnataka is that the entire land of 13000 acres is private land and taken on lease for a period of 28 years which is first of its kind in World with ownership of land vesting with land owners, as acquiring of land is a major hurdle in implementation of any project. The land owners will be getting land lease charges of Rs. 21,000/acre/annum with 5% escalation once in every two years on the base rate. Pavagada is one of the most backward Taluks in the state of Karnataka. The area is dry and due to lack of water for irrigation, the farmers are suffering due to lack of source of employment. Establishment of solar park in this area will create local employment to the public in a large extent and will improve the revenue to the Government. In states like Madhya Pradesh, Uttar Pradesh, the land is mostly Government owned and there is as such no problem in acquisition of land. In Haryana, a solar park of capacity 500 MW is being developed by Saur Urja Nigam Haryana Ltd (SUN Haryana). Sun Haryana is facing challenges in acquisition of land as the panchayat land lease policy of Government of Haryana does not allow sub-leasing of land. However, sub-leasing of land to SPDs is required for setting up of solar projects. In Maharashtra, there are three solar parks each of capacity 500 MW. Out of these three
solar parks, two solar parks are being developed by private entrepreneurs. Both the private entrepreneurs are facing challenges in acquisition of land. Further, incidence of stamp duty for non-agricultural lands is much higher than the duty payable for agricultural land. In order to address this, issue the government decided to exempt industries covered under the industrial policy from payment of stamp duty. However, solar parks and solar projects are not included as an industry as per this policy. The land conversion charges and stamp duty charges which are under the ambit of the State Governments. Incidence of stamp duty would escalate the cost of solar parks exorbitantly. (ii) Financing: Significant investment is required to be made for development of solar parks which include acquisition of land, get the land developed and provide necessary infrastructure like road connectivity, transmission infrastructure etc. Further, investment is also required to be made in the operation & maintenance of solar parks, employing staff and other activities like marketing etc. The entire cost of development including cost involved in acquisition of land forms the total cost of the project. Under the Solar Park Scheme, the Government of India provides Central Financial Assistance (CFA) of up to Rs. 20.00 lakh per MW or 30% of the project cost including grid-connectivity cost, whichever is lower, for development of the solar park. While CFA covers only part of the park cost, the remaining amount is being taken from the Solar Project Developers (SPDs) as one-time upfront charges and recurring O&M charges, when they enter the park to set up solar projects. This financial model is being adopted in most of the solar parks. Few cases are given as under: In Andhra Pradesh, APSPCL is meeting their financial requirement for development of solar parks partly by Central grant (Rs. 12.00 Lakh/MW) and the balance fund is met by collecting one-time solar power development expenses (around Rs.40 Lakh/MW) from the solar power developers (SPDs). Further, O&M charges (Rs.2.50 to 3.00 lakh/MW) are also collected annually from the SPDs to meet the yearly expenditure to be incurred towards maintenance of solar power park. ISBN-978-81-932091-2-7
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In Karnataka, KSPDCL is meeting their financial requirement for development of solar parks partly by Central grant (Rs. 12.00 Lakh/MW) and the balance fund is met by collecting one-time solar power development expenses (around Rs.28 Lakh/MW) from the solar power developers (SPDs). Further, O&M charges (Rs.2.50 to 3.00 lakh/MW) are also collected annually from the SPDs to meet the yearly expenditure to be incurred towards maintenance of solar power park. In Bhadla Phase-II solar park of Rajasthan, Rajasthan Solarpark Development Company Limited (RSDCL) is meeting their financial requirement for development of solar parks partly by Central grant (Rs. 12.00 Lakh/MW) and the balance fund is met by collecting onetime solar power development expenses of Rs. 6.00 Lakh/hectare. Further, O&M charges (Rs. 30,000/- per annum per hectare) are also collected annually from the SPDs to meet the yearly expenditure to be incurred towards maintenance of solar power park. The onetime charges put an upfront burden on the selected SPDs. In order to reduce this burden, Ministry of New and Renewable Energy is tying up with different bi-lateral and multi-lateral financing agencies for long tenure and concessional loan for development of solar parks. The long tenure and concessional financing from bi-lateral and multi-lateral financing agencies would be utilized in development of the internal infrastructure, such as, internal transmission system, water access, road connectivity, communication network, etc. of the solar parks. With low cost financing, the solar power generated in the solar parks is expected to be cheaper. The Rewa Solar Park in Madhya Pradesh is one of the solar parks availing World Bank loan for development of park infrastructure. The World Bank loan has a component called Clean Technology Fund (CTF), the USD interest rate of which is 0.25% per annum fixed over the life of the loan. The door-to door tenor of IBRD financing is 24 years and that of the CTF could be 40 years. The Rewa solar park is financed by combination of the following three components: a) Central Financial Assistance (CFA) from Government of India under the scheme for
“Development of Solar parks and Ultra Mega Solar Power Projects” @ Rs. 12 Lakh/MW or 30% of the cost of development of internal infrastructure of solar park, whichever is lower. It may be treated as part of equity of the SPPDs; b) SPPD’s internal resources (equity of the SPPDs or land contribution) and annual park charges / user fee to be charged from the selected SPDs. However, collection of upfront charges by the SPPDs from the SPDs is not allowed for the financial assistance received from the World Bank and Central Grants received from MNRE. c) Financial assistance from World Bank. However, the financial assistance from World Bank would be limited to 50% of the total cost of development of internal infrastructure of the Solar Park. (iii) Grid Integration of Solar Parks: In case of large scale renewable generation, particularly for large scale solar parks, it is not possible to absorb the energy locally. The scenario is more prominent especially during the period of high solar generation wherein electricity demand is not at peak level. Transmission system is required to be planned for integrating such large scale solar power parks with the State grid as well as with the inter-state/national grid. Integrated planning approach would ensure that solar generation does not have to be backed down during solar maximized scenario or other than peak demand period and local grid network must be stable even when solar generation is not available during night time. This integration provides reliability of transmission and power supply to the whole system. Owing to intermittent nature of solar energy, it requires support from the grid. The transmission capacity requirement for grid integration of solar parks shall also depend upon quantum of power to be transmitted/integrated. Once all the solar parks are commissioned, solar projects of aggregate capacity 40 GW would be connected to the grid. To evolve plan for grid integration of large scale solar/wind generation capacities, POWERGRID has been entrusted by Ministry of Power (MOP) to formulate Grid Integration Plan for envisaged renewable capacity addition by 2022 as Green Energy Corridors-II. The ISBN-978-81-932091-2-7
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scope of Green Energy Corridors-II includes identification of transmission scheme, its implementation, financing strategy etc. The power evacuation arrangement for the identified solar parks approved under Pahse-I of the Solar Park Scheme envisaged through Intra state & Interstate evacuation is evolved as Green Energy Corridors-II (Part-A). The report on Green Energy Corridor-II covers the plan for grid integration of solar parks at interstate level and intra-state level. POWERGRID has carried out studies to identify transmission infrastructure requirement for solar parks in various states. To carry out the studies, inputs like existing generation data, information regarding details of solar parks i.e. location, quantum and time frame in various states, pocket wise RE & conventional generation capacity addition program in time frame of 2016-17 & 2018-19 has been considered. Information about existing and planned transmission system including various transmission corridors High Capacity Corridors/Green Energy corridors, wind and solar generation pattern, network topology etc. has been taken into account in studies. In order to facilitate transfer of power from envisaged solar parks, inter-state & intrastate transmission scheme is evolved with total estimated cost of Rs 12,786 crore. (iv) Difference in Gestation period of Solar Generation and Transmission: Gestation period of solar projects is very less (12-18 months) vis-a-vis transmission development (24-36 months) for integration with the grid. Further, the capacity utilization factor for solar generation is low resulting into high transmission tariff. In view of the above, Transmission development for solar generation faces two critical issues i.e. matching implementation period (Generation vis-a-vis Transmission) as well as transmission tariff. As per the prevailing regulation in India, interstate transmission system for generation project is evolved based on Long Term Access/Connectivity application by the applicant. However, keeping in view of short gestation period of RE, transmission development need to be done much ahead of generation without considering
LTA/Connectivity application. However, location of the generation project and its quantum needs to be firmed up in advance so that transmission system planning can lead the generation and its implementation may match with solar generation development. An approach should also be developed to build the transmission for High potential RE zones in anticipation of subsequent RE development rather than waiting for RE project to first come up with their requirements i.e. Transmission to lead generation approach. (v) Forecasting of Solar Generation: Solar generation forecasting & its real time monitoring are important tools to address variability & uncertainty aspect of its grid integration. State-of-the-art forecasting helps grid operator to manage power system balance for economic, reliable & secured operation of the grid even in high RE penetration regime. In this direction, establishment of Renewable Energy Management Centers (REMC) colocated with SLDCs/RLDC/NLDC in RE resources rich states was proposed as part of Green Energy Corridor-I. REMC shall be responsible for forecasting of RE generation in their jurisdiction for different time horizons, real time tracking of RE generation and close co-ordination with their SLDC/RLDC for smooth grid operation. It is proposed that the envisaged solar parks shall be integrated with these REMCs also for monitoring, scheduling & forecasting purpose. (vi) Ancillary Services: Ancillary Services, defined as: "those services necessary to support the transmission of electric power from seller to purchaser given the obligations of control areas and transmitting utilities within those control areas to maintain reliable operations of the interconnected transmission system." The two most important ones are the a) Reserves of generation to support falls of generation and with the goal to maintain the frequency and interchanges in the case of loss of some generation. b) Maintain the voltage profile in the system High Renewable penetration scenario necessitates increased balancing and system flexibility requirements. In such scenarios, to ensure the reliability of the power system and ISBN-978-81-932091-2-7
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quality of electricity, additional services viz. Ancillary services may be needed by the system operator to achieve system balancing in real time. The Detailed Procedure for Ancillary Services Operations for Inter-state has been approved by CERC in March, 2016. The Ancillary Services have been rolled out for implementation in April 2016. Similar framework needs to be implemented in the states also. 11. Conclusion The concept of solar parks has indeed emerged as a powerful tool for the rapid development of solar power projects in India. Assured availability of land and transmission infrastructure are the major benefits of a solar park. The recent downward trends in solar tariff may be attributed to the factors like economies of scale, assured availability of land and power evacuation systems under the Solar Park Scheme. The issues/challenges can be resolved by concerted efforts of all stake holders. The major benefits of solar parks are 50,000 MW of solar projects can be set up in 50 proposed solar parks in various States/ UTs of the country.
Availability of solar power at competitively low tariffs. Total capacity when operational, will generate 64 billion units of green energy/electricity per year @1.6 million unit per MW. Achievement of 40,000 MW solar capacities would contribute to long term energy security of country and ecological security by reduction in carbon emissions and carbon footprint, as well as generate large direct & indirect employment opportunities in solar and allied industries like glass, metals, heavy industrial equipment etc. Installation of 40,000 MW of solar will lead to abatement of around 56 million tons of CO2 per year over its life cycle. Creation of solar parks has attracted foreign players to invest in solar projects in India. More investment opportunities will enhance income. The solar parks will also provide productive use of abundant wastelands which in turn facilitate development of the surrounding areas. *****
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Interconnected Hybrid RE Network with Embedded VSC MTDC Transmission System for Secure and Efficient Power Delivery: Modeling and Steady State Response Analysis Jeetendra Singh Rathore, Mukesh Lodha, Shivani Johari, Rituraj Soni Sri Balaji College of Engineering & Technology, Jaipur (Rajasthan) Jsrathore9@gmail.com Radhey Shyam Meena, Ministry of New & Renewable Energy, New Delhi (India) Corresponding Author: rshyam.mnre@gov.in Abstract This paper deals with one of the major challenge in the field of Indian Power Sector with a objective of to provide a framework for promotion of large grid connected and interconnected Renewable Energy (RE) networks for optimal and efficient utilization of transmission infrastructure and land, reducing the variability in renewable power generation and thus achieving secure and better grid stability with improved power quality at delivery end. The proposed studies are going to encourage new technologies, methods and way-outs involving combined operation of wind and solar PV power generation systems with embedded Voltage Source Converter (VSC)-MTDC transmission system, to transmit bulk power, to control power, to modulate power and to improvement in system stability. The paper focused on a case study of two separate-interconnected systems through a DC transmission network of the capacity of 24 kW wind power generation system and 24 kW solar power generation system has been used for analysis of steady state response of the system. Performance of the system and steady state response analyze using MATLAB techniques and is better then non-RE network and also found in acceptable range for secure operation and better grid stability. Key words: Integrated Solar Wind System, Interconnected Renewable Energy Network (IREN), Multi Terminal Direct Current (MTDC) Transmission System, Voltage Source Converters (VSC), Power Quality (PQ) of India Power Sector (IPS), Grid Stability (GS). 1. Introduction India has set an ambitious target of reaching 175 GW of installed capacity from renewable energy sources including 100 GW from solar and 60 GW from wind and plan for 10 GW solar wind hybrid capacity by the year 2022 for which the Government of India has launched several schemes for promotion of solar and wind energy in the country to achieve the target. The Government is promoting renewable energy through fiscal and promotional incentives such as capital subsidy, tax holiday on the earnings for 10 years, generation based incentive, accelerated depreciation, viability gap funding (VGF), financing solar rooftop systems as part of home loan, concessional excise and custom duties, preferential tariff for power generation from renewables, and foreign
direct investment up to 100 per cent under the automatic route etc. The country has already crossed a mark of 32 GW of wind and 12.28 GW of solar power installed capacity up to March 2017[1]. Solar and wind power being infirm in nature impose certain challenges on grid security and stability. Studies revealed that solar and winds are almost complementary to each other and hybdridation of two technologies would help in minimizing the variability apart from optimally utilizing the infrastructure including land and transmission system. Superimposition of wind and solar resource maps shows that there are large areas where both wind and solar have high to moderate potential. The existing wind farms have scope of adding solar PV capacity and similarly there may be wind potential in the vicinity of existing ISBN-978-81-932091-2-7
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solar PV plant. Suitable policy interventions are required not only for new wind-solar hybrid plants but also for encouraging hybridization of existing wind and solar plants [2-3]. Performance and feasibility explained in [4] for an integrated hybrid system in which a solar cell, wind turbine, fuel cell and ultra capacitor system is developed using a novel technique to complement each other. Hybrid renewable energy systems in [5] help to increase system reliability and improve power quality. This paper explained the way to integrate the power output from solar photo voltaic array, fuel cell stack and battery with a provision for on site hydrogen generation by means of an electrolyzer and H2 tank. The control strategy handles the source power effectively by considering the limited life cycle of storage devices. In [6] one such novel initiative wherein electricity requirement is fulfilled by renewable energy presented. In this study, an integrated hybrid system is used to generate electricity from the combination of solar and wind energy. Fuel cell and electrolyzer also used for storage and better performance on remote applications. A combination of a solar cell, fuel cell, and ultra capacitor system for power generation was presented in [7]. In this work the available power from the renewable energy sources is highly dependent on environmental conditions such as wind speed, radiation, and ambient temperature. Fuel cell and ultra capacitor system were used to overcome the deficiency of the solar cell and wind system. This system is used for off-grid power generation in noninterconnected or remote areas. High Voltage DC Transmission system is used to transmit bulk power, to control power, to modulate power for improvement in system stability. Mostly voltage source converters used as insulated gate turn of thyristor in dc network. In [8] it was described the basic modeling and simulation of voltage source converter in HVDC are explained. In [9] it was proposed to integrate large capcity renewable energy into the existing power
grid, provide remote islands with reliable power supply, and regulate the frequencies. Though, to expand an existing traditional point to point line controlled converter HVDC line into hybrid MTDC system achived [10]. One of the most suitable applications of VSC-based MTDC transmission systems is in the field of wind farms interconnection. Of course there are many publications which investigated the possibility of utilizing CSC converters for aggregation of offshore wind farms [11-13]. However, CSCs need for reactive power support at the point of connection which consequently leading the connected AC system to have a high enough short circuit ratio [14-15]. Some literature has proposed that installation of Static Compensators (STATCOM) at the point of connection CSC terminal to offshore station can solve this problem [16]. However, the proposed solution brings about other issues such as a wider footprint, more losses, and more complexity in the wind power system. Contrarily, based on VSC HVDC link characteristics such as rapidly and independently control of active and reactive powers and black-start capability, these VSC links are superior to CSC links for wind farm grid interconnection [17-19]. That is why VSC links have been proposed as a more rational and efficient solution to be used for interconnection of wind farms. Therefore, due to these especial characteristics of VSC links, such systems are mostly used for wind farms interconnections. Reference [20] proposed the construction of a low voltage DC grid using VSCs to aggregate the power of several wind turbine units. It has also been proposed using hybrid MTDC systems based on VSCs and CSCs for subtransmission and distribution systems in urban areas of large cities [21]. 2.
An Approach towards Integration Under the integration category of windsolar hybrid power plants, Wind Turbine Generators (WTGs) and Solar PV systems ISBN-978-81-932091-2-7
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have been configured to operate at the same point of grid connection. There can be two different approaches towards integrating wind and solar depending upon the size of each of the source integrated and the technology type. Here we concluded two approaches i.e. (a) Technology front (b) Size of the source On the technology front, in case of fixed speed wind turbines connected to grid using an induction generator, the integration can be on the HT side at the AC output bus. However, in case of variable speed wind turbines deploying inverters for connecting with the grid, the integration can even be on the LT side before the inverter i.e. at the intermediate D.C bus. The second important aspect would be related to the sizing – which would depend on the resource characteristics. In order to achieve the benefits of hybrid plant in terms of optimal and efficient utilization of transmission infrastructure and better grid stability by reducing the variability in renewable power generation, in the locations where the wind power density is quite good, the size of the solar PVs capacity to be added as the solarhybrid component could be relatively smaller. On the other hand, in case of the sites where the wind power density is relatively lower or moderate, the component of the solar PV capacity could be relatively on a higher side. However, a wind-solar plant will be recognized as hybrid plant if the minimum ratio of total rated capacity of WTGs and solar PV plant is 1: 0.25. The implementation of wind solar hybrid system has depends on different configurations and use of technology detailed below: (a) Wind-Solar Hybrid- AC integration: In this configuration the AC output of the both the wind and solar systems is integrated either at LT side or at HT side. In the later case both system uses separate step-up transformer and HT output of both the system is connected to common AC Bus-bar. Suitable control equipment is
deployed for controlling the power output of hybrid system. (b) Wind-Solar Hybrid- DC integration: DC integration is possible in case of variable speed drive wind turbines using converter-inverter. In this configuration the DC output of the both the wind and solar PV plant is connected to a common DC bus and a common invertors suitable for combined output AC capacity is used to convert this DC power in to AC power. 3.
Modeling of Interconnected Hybrid Network In this section an interconnected hybrid network of the wind and solar based configuration is presented. With their advantages of being abundant in nature and nearly non-pollutant, renewable energy sources have attracted wide attention. Wind power is one of the most promising clean energy sources since it can easily be captured by wind generators with high power capacity. Photovoltaic (PV) power is another promising clean energy source since it is global and can be harnessed without using rotational generators. In fact, wind power and PV power are complementary to some extent since strong winds mostly occur during the night time and cloudy days whereas sunny days are often calm with weak winds. Hence, a wind–PV hybrid generation system can offer higher reliability to maintain continuous power output than any other individual power generation system. This kind of hybrid generation system can be divided into two main types—the stand-alone off-grid system and the gridconnected system. For the grid-connected system, the interface between the hybrid generation system and the power grid has to be specially designed. For the standalone off-grid system, the hybrid generation system can easily be set up in remote and isolated areas where a connection to the utility network is either impossible or unduly expensive. Over the years, there has been only few research ISBN-978-81-932091-2-7
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work on the standalone wind–PV hybrid generation system in which the wind generators are focused on induction machines. The purpose of this thesis is to present a new way of grid connected and interconnected wind–PV hybrid generation system with embedded VSCDC transmission system for secure and efficient power delivery to the end users. Solar System The solar radiation resource is fundamentally determined by the location on the earth´s surface, the date, and the time of day. These factors determine the maximum level of radiation. Other factors such as height above sea level, water vapor or pollutants in the atmosphere and cloud cover decrease the radiation level below the maximum possible. Solar radiation
does not experience the same type of turbulence that wind does but there can be variations over the short term. Most often, these are related to the passage of clouds. Simulink blocks of the different components in the experimental model are shown in Figure. In the figure, these are the PV array system block, inverter block, three-phase source block, controller block and the load block respectively. This model also includes the MPPT model, in the next chapter, these blocks will be discussed individually will look into how the models are implemented as shown in figure 1 and figure 2. This model based on 24 kW system which design internally in figure1 and full diagram as shown in figure 2.
Figure 1: Internal model of solar system based on the equations ISBN-978-81-932091-2-7
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Figure 2: 24 kW PV system ISBN-978-81-932091-2-7
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Wind System Ultimately wind resources are driven almost entirely by the sunâ&#x20AC;&#x2122;s energy, causing differential surface heating, but they tend to be very dependent on location. Over most of the earth, the average wind speed varies from one season to another. It is also likely to be affected by general weather patterns and the time of day. It is not uncommon for a site to experience a number of days of relatively high winds and these days to be followed by others of lower winds, strongly interfering with the operation planning of a hybrid system comprehending wind turbines. The wind also exhibits short term (seconds to
minutes) variations in speed and direction, known as turbulence. The power output of wind turbine relates to wind speed with a cubic ratio. Both the first order moment of inertia (J) and a friction based dynamic model for the wind turbine rotor and a first order model for the permanent magnet generator are adopted. The dynamics of the wind turbine due to its rotor inertia and generator are added by considering the wind turbine response as a second order slightly under-damped system. Using this simple approach, small wind turbine dynamic is modeled as shown in figure 3 and figure 4.-
Figure 3: Internal Model of 3 kW wind system
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Figure 4: 24 kW Wind System
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Voltage Source Converter (VSC) Based Multi Terminal Dc (MTDC) System Two basic converter technologies are used in modern HVDC transmission systems. These are conventional line commutated, current source converters (CSC) and self commutated, voltage-sourced converters (VSC). Two types of configuration can be adopted in Multi Terminal DC (MTDC) systems. The parallel connection which allows DC terminals to operate around a common rated voltage VDC. The second configuration is the series connection where one of the converters controls the current around a common rated current and the power is controlled by the rest of converters. This configuration is well suited for Current Source Converter (CSC) MTDC systems since CSCs in the DC side are functioning as a voltage source which can be connected in series without need for special switching. Compared to CSCs, VSCs are functioning as an ideal current source in its DC sides allowing the parallel connection of several DC terminals without posing any technical difficulties. As perviously mentioned, in a VSC link the direction of power can be changed through the reversal of current direction and the voltage polarity at the DC side can remain unchanged. These capabilities are perfectly suited for constructing an MTDC system. VSC MTDC systems with parallel connected converters have a great potential to be used in the future bulk power systems. Possibility of such connections has led to the proposition of a DC ’Super Grid’ that could connect several renewable energy sources to a common MTDC network. Utilizing VSC-based MTDC systems can give the following possibilities to the power systems- (a) Control of the MTDC system, (b) increasing the flexibility of power flow controllability, (c) enhancing transmission capacity, (d) improving the voltage profile in the network, and integrating large scale of renewable or new energy sources positioning at different locations.
VSC based multi terminal DC system contains number of VSC’s either offshore or onshore connected to same DC link. VSC connected to generating station can be offshore or onshore depending upon renewable energy nature i.e. tidal energy, offshore wind farms, solar panels etc. But throughout this paper we will consider offshore wind farms as it have more capacity to generate electricity and can meet the needs. Each offshore wind farm requires an offshore substation used to install VSC converter and number of connections to DC link depends upon MTDC application, same in the case of PV system. Before designing MTDC system, design engineer must consider technoeconomic factors imposed by utility. Economic factors include geographical location, number of offshore substations, onshore platforms, DC link, DC Circuit Breaker, ultra-fast mechanically actuated disconnector, and cost. Technical aspects can be: effective utilization of MTDC lines, rating of DC link, protection of MTDC under abnormal conditions and support to connected AC network. MTDC system must satisfy the security and Quality of Supply Standard as well as DC voltage of MTDC system must be constant during abnormal conditions on AC sides of VSC DC. Each terminal of VSC based MTDC system must be able to control active and reactive power, support AC network voltage and frequency independently. VSC based MTDC system behavior strongly depends upon the control nature which mainly rely on system topology and kind of AC grid connection. Figure shows the VSC station model with its elements. The model at the DC side is depicted as single line representation. The model consists of AC buses, coupling transformer, series reactance, AC filter, converter block on the AC side and on the DC side, DC Bus, DC filter and DC line. As it can be seen each VSC station is connected to the AC grid at the so called point of the common connection (PCC). ISBN-978-81-932091-2-7
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PCC is connected to AC side of VSC through a converter transformer, shunt filter and finally phase reactor. On the other side i.e. DC side, DC bus, at which a shunt DC capacitor is connected to the ground, is connected to the VSC from one side and to DC line from other side as shown in figure 5. .
Figure 5: VSC Station Model Interconnected Network In this work, a detailed dynamic model and simulation of an interconnected hybrid
power system are developed using the VSC topology. Modeling and simulations are conducted using MATLAB/Simulink software packages to verify the effectiveness of the proposed system. The results show that the proposed hybrid power system can tolerate the rapid changes in natural conditions and suppress the effects of these fluctuations on the voltage within the acceptable range and supply power at end user with better quality. This system has 48 kW PV generation System, a 48 kW wind energy system, a 500 kM DC transmission line and VSC universal bridge for conversion purpose used. It is used to step up voltage to DC 440 V and invert to Vrms, 50 Hz AC. The renewable energy based hybrid system model made in Simulink is shown in Figure 6, 7 and 8.
Figure 6: Interconnected through a DC Transmission Network and VSC system
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Figure 7: System-I of Capacity 24 kW wind and 24 kW PV system
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Figure 8: System-II of 24 kW wind and 24 kW PV system
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Simulation Results of the Interconnected Network
Figure 9: Wind Solar Power
Figure 10: Hybrid Voltage
Figure: 11 Voltage and Current of Wind System ISBN-978-81-932091-2-7
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Figure 12: 3-Phase Volatage of wind
Figure 13: Voltage and Current for Solar System
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Figure 14: 3 Phase Volatage for PV System
Figure 15: Out put Voltage of System 1
Figure 16: Out put voltage of System 2
Figure 17: Combined 3-Phase Volatge after Transmission
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Figure 18: Interconnected 3-Phase Voltage The system presented in this study is Figure 10 also illustrates that parallel simulated under several conditions like operation of the system continues without different input voltages and different load any interruption, even input voltages of sharing ratios. Some of the simulation the converters have different values. The results are given in this section. As ripple on the output voltage of the system mentioned previously, the system is is given in Fig. 17. It has been obviously controlled by the PI control blocks. If the seen that the ripple is quite less (1.2 V), converters operate uncontrolled, some around 0.385 %, which is highly serious problems may occur like considerable value. Moreover, this ripple overshooting and instability. has been minimized by controlling the Figure 9 illustrates waveforms of wind and converters with high switching solar power in the case of hybrid system. frequencies without using an external Figure 10 illustrates waveforms of wind filter. and solar voltage. Figure 11 illustrates waveforms of Voltage and Current of Steady State Response: Wind System. Figure 12 illustrates waveforms of 3 phase voltage of wind system. Figure 13 illustrates waveforms of Voltage and Current of PV System. Figure 14 illustrates waveforms of 3 phase voltage of PV system. Figure 15 illustrates waveforms of voltage in the case of hybrid system for system 1. Figure 16 illustrates waveforms of voltage in the case of hybrid system for system 2. Figure 17 illustrates waveforms of voltage in the case of interconnected system. Figure 18 illustrates waveforms of 3 phase voltage in the case of interconnected system. Voltage and current signals when the converters operate uncontrolled. Also, parallel connection operation is achieved in a very short time, around 0.3 s, which means that the system has a fast response time. In the study, another test is carried out to observe the system response against the load variations after the system is passed to steady state conditions. The system response against the load variations is illustrated in Fig. 18 when the load is shared equally. As depicted on the figure, the load value is 100 ohm between 0 s and 1 s. The presented load sharing system has been also tested for different sharing ratios. This situation can be observed in Fig. 10, where the wind system feeds the load with 70 % load ratio, and the PV system feeds it with 30 % load ratio. ISBN-978-81-932091-2-7
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sharing techniques in order to ensure power flow control among the energy sources. The system presented is also tested against the instant load variations on the output side. Negative effects of the load variations are eliminated in a very short time and load sharing operation is maintained successfully under new load conditions. The system performance can satisfy the user in all perspectives. It could regulate the output power properly while its transients were damped very quickly.
Figure 19: Bode Nichols and Pole Zero Charstrstics for the System Figure 19 explain the Bode Nichols and Pole Zero Charstrstics for the System Conclusion: In this study, an effective parallel connection model for interconnected hybrid network has been developed to use it in multi-input energy systems. Firstly, the system is modelled and mathematically analysed. Once the converter is mathematically modelled, it is then simulated in MATLAB/Simulink in order to test the mathematical model and to define the required circuit parameters. Then, a model for parallel connection operation is also developed and simulated in MATLAB/Simulink. According to simulation results, it has been observed that ripples on the output voltage of the converters are considerably minimized. Furthermore, parallel operation of the system has been maintained without any interruption, even though the energy sources have different input voltages. Transient state analysis of the system is also realized and it is observed that the system reaches to steady state conditions in a very short time. In the system presented, load sharing operation among the converters is carried out by realizing the active current
Reference: 1. Radhey Shyam Meena, Dr. Nitin Gupta, Prof. D. K. Palwaliya, Dr. A. K. Sharma "Integration of Solar Parks: Global Impact of Intermittent RE Generation" International Journal of Research and Innovation in Social Science -IJRISS vol.1 issue 4, pp.0715 2017 2. Radhey Shyam Meena, Dilip Nigam, Dr. A. K. Tripathi, "Journey Towards Sustainable Growth with Energy Security and Global Tracking Framework: Case of Hybrid Project" Conference on Metering India 2017 towards smart and sustainable utilities organized by IEEMA India with IEC, MNRE & MoP, 06-07 April 2017 (Published Paper no. 41 of proceeding). 3. Radhey Shyam Meena, Bharat Dubey, Dr. Nitin Gupta, Dr. D K Sambariya, A S Parira, M K Lodha, ’’ Performance and feasibility analysis of integrated hybrid system for remote isolated communities’’ IEEE Publication, 2016 IEEE International Conference on Electrical Power and Energy Systems, ISBN 978-1-5090-2476- 6/16/$31.00 ©2016 IEEE, December 2016. 4. Radhey Shyam Meena, Dilip Nigam, Dr. Nitin Gupta, M K Lodha ‘’Control Strategy of a Stand-Alone Hybrid Renewable Energy System for Rural Home Application’’ IEEE Publication, 2016 IEEE Seventh India International Conference on Power Electronics ISBN-978-81-932091-2-7
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(IICPE 2016), ISBN 978-1-50904530-3/16/$31.00 ©2016 IEEE, November 2016. 5. Radhey Shyam Meena, "Sustainable Development of Remote Isolated Communities Using Integrated Hybrid System: A New Generation of Renewable Energy'' Akshaya Urja, Magazine of Ministry of New & Renewable Energy, Volume 10 Issue 2, pp 42-45, October 2016. 6. Radhey Shyam Meena, Deepa Sharma, Dr. D. K. Birla,”PV-Wind Hybrid System with Fuel Cell & Electrolyzer”, International Journal of Engineering Research ISSN: 2347-5013 Volume No.4, Issue No.12, pp: 673-679, 01 Dec. 2015. 7. Radhey Shyam Meena, M K Lodha, “Modeling and Simulation of Voltage Source Converter in High Voltage Dc System" International Journal of Multidisciplinary Research and Modern Education, ISSN (Online): 2454 - 6119 Volume I, Issue II, 2015, p p 166-171, 2015. 8. Radhey Shyam Meena, M K Lodha, "Analysis of Integrated Hybrid VSC Based Multi-Terminal DC System Using Control Strategy", International Journal of Advanced Research in Electrical, Electronics and Instrumentation Engineering. ISSN (Print): 2320 – 3765 ISSN (Online): 2278 – 8875 Vol. 4, Issue 12, pp-98239830, December 2015. 9. IEEE Industrial and Commercial Power Systems Department Working Group Report of the Protection Committee, “Application Considerations of Static Over current Relays: A Working Group Report” IEEE Trans. Industry Applications., Vol. 33, pp.1493 - 1499. 10. Wang P, Xiao J, Setyawan L, Jin C, Hoong CF (2014) Hierarchical control of active hybrid energy storage system (HESS) in DC microgrids. In: 2014 IEEE 9th conference on industrial
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19. W. Lu and B. T. Ooi, “Multi-terminal lvdc system for optimal acquisition of power in wind-farm using induction generators,” in Power Electronics Specialists Conference, 2001. PESC. 2001 IEEE 32nd Annual, vol. 1, 2001, pp. 210 –215 vol. 1. 20. W. Lu and B.-T. Ooi, “Optimal acquisition and aggregation of offshore wind power by multiterminal voltagesource hvdc,” Power Delivery, IEEE
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Mitigation of Inrush Current in Power Transformer using Prefluxing Technique Avinash Yadav, Jyoti Kant Sharma, Shivani Johari, Mukesh Lodha Sri Balaji College of Engineering & Technology, Jaipur (Rajasthan) Swati Agariya National Institute of Solar Energy, Gurugram, India 122005 Poonam Meena DMRIPC Pvt. Ltd., New Delhi (India) Email: rspunam2016@gmail.com Corresponding Author: aviyadava@gmail.com , swati.agariya12april@gmail.com Abstract: Transformer is the most expensive component in power system. So this is very necessary to provide sufficient protection for that component. There are many problems which may occur in transformer like over current, overvoltage etc because of faults which can damage the transformer. Damage in transformer can create a serious problem in transmission or distribution of system. Three phase transformer produces severe starting current which is called inrush current. This inrush current induces harmonics which is high in magnitude and generate at the time of re energisation of transformer and it is 2 to 5 times greater than rated current. This current generates several problems like mal operation of relays, damaging the windings and core of transformers. In this paper a technique to mitigate inrush current in three phase transformer which involves injecting some amount of DC flux in the primary of transformer has been proposed, this process is known as prefluxing. After setting the initial fluxes of the transformer it is energized by conventional controlled switching. To verify the effectiveness of the proposed prefluxing method and to mitigate inrush current for transformer, a MATLAB®/simulation model is designed and developed. Keywords: Inrush Current, Transformer, Prefluxing, MATLAB®/Simulink to the magneto motive force (mmf) in the 1. INTRODUCTION core and the mmf is proportional to winding Nonlinear properties of circuit elements can current, the current waveform will be inbe a potential source of abnormalities. phase with the flux waveform, and both will Transformer magnetizing inrush current is be lagging the voltage waveform by 90º. In an example. When a transformer is initially an ideal transformer the magnetizing current connected to a source of AC voltage, there would rise to approximately twice its normal may be a substantial surge of current through peak value as well generating the necessary the primary winding called inrush current. mmf to create this higher-than-normal flux. This is analogous to the inrush current However, most transformers aren’t designed exhibited by an electric motor that is started with enough of margin between normal flux up by sudden connection to a power source, peaks and the saturation limits to avoid although transformer inrush is caused by a saturating in a condition like this and so the different phenomenon. core will almost certainly saturate during We know that the rate of change of this first half-cycle of voltage. During instantaneous flux in a transformer core is saturation disproportionate amounts of mmf proportional to the instantaneous voltage are needed to generate magnetic flux. This drop across the primary winding or as stated means that winding current which creates before, the voltage waveform is the the mmf to cause flux in the core will derivative of the flux waveform, and the flux disproportionately rise to a value easily waveform is the integral of the voltage exceeding twice its normal peak. This is the waveform. In a continuously-operating mechanism causing inrush current in a transformer, these two waveforms are phasetransformer primary winding when shifted by 90º. Since flux (Φ) is proportional connected to an AC voltage source. As the ISBN-978-81-932091-2-7
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magnitude of the inrush current strongly depends on the exact time that electrical connection to the source is made. If the transformer happens to have some residual magnetism in its core at the moment of connection to the source, the inrush could be even more severe. Because of this transformer over current protection devices are usually of “slow-acting” variety so as to tolerate current surges such as this without opening the circuit. The inrush phenomenon was known to people from years when the transient behavior of RL circuits was studied. The studies related to magnetic materials, BH curves, saturation, etc. enabled scientists to understand the concept in a better way. Gaowa Wuyun et. al. in this paper, introduces the residual flux of transformer ferromagnetic-core which is not random when it enters into Power System without load form last cutting off. Firstly, the relationship between residual fluxes and the last exciting current was discussed, then hysteresis loop was divided into three antisymmetric sections according to reversibility of magnetic domains Methods were proposed to calculate residual flux approximately section by section based on the principle of similar-shape and ferromagnetic characters [1]. Scientists started modeling of inrush current by constructing a low frequency model of transformer. A.M. Miri, et. al. Modeled a 100 MVA transformer and obtained inrush current in all the three phases [2]. Kunal J Patel discuss the effects of inrush current in transformers they describe the fundamental theory and relevant laws of the transformer and inrush current. A number of factors affecting inrush current are discussed. The inrush current theory and their equation are derived. The effects of inrush current are described in brief. The Matlab Sim-Power system is used for the simulation. The simulation results compared with each other and also data available from actual same size transformer. Finally six solutions to inrush current mitigation techniques with a practical low cost answer are provided [3]. John H. Brunk ahnd Klaus J. Frohlich theoretically proposed controlled switching
as a method to mitigate inrush current in a single phase transformer by making a transformer model considering saturation characteristics of magnetic core and an inevitable residual flux. They also introduced the concept of core flux equalization which means equalization of flux in all the three limbs of transformer core when one of the phases is energized. They calculated the inrush in their model for simultaneous closing, rapid closing and delayed closing of circuit breakers [4]. Ramsis S. Girgis et. Al. describe the characteristic of inrush current of present design of power transformers. They says that Accurate calculation of peak and % 2nd harmonic of inrush current is critical to appropriate selection of relay protection of a power transformer. A description is given of a rigorous calculation of magnitude and wave-shape of inrush current as a function of the transformer design parameters as well as parameters of the system to which the transformer is connected [5] Hongkui Li. et. al. shown the analysis of three phase power transformer winding forces caused by magnetic inrush and short circuit currents. These forces are compared with the corresponding forces due to short-circuit of the windings. Three-dimensional finite element computation of three-phase power transformer is carried out based on the maximum permissible magnetic inrush current value where its amplitude is the same as the rated short-circuit current. To verify the computation results, they are compared with those obtained using Ansys software simulation [6]. Salman Kahrobaee et. al. worked on the investigation and mitigation of inrush current in power transformer during black start of an independent power producer plant, energy and power engineering. They describe that when a transformer is energized by the utility, a typical inrush current could be as high as ten times its rated current. This could cause many problems from mechanical stress on transformer windings to harmonics injection and system protection malfunction. There have been numerous researches focusing on calculation and mitigation of the transformer inrush current. With the development of ISBN-978-81-932091-2-7
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smart grid, distributed generation from independent power pro-ducers (IPPs) is growing rapidly. They simulate the simulation model in DIgSILENT Power Factory software [7]. Mukesh Nagpal et. al. proposed a technique to mitigate inrush current of start transformer by introducing a neutral resistor. They simulated results for both, simultaneous closing and delayed closing of circuit breakers [8]. Juei Shyu et. al. proposed a model to reduce inrush current of a single-phase transformer by using voltage series compensation. he used voltage sag caused by switching to control the voltage of a compensator [9]. In [10-17] several worked on sequential energisation of three phase transformers along with a neutral resistor. They made a steady state analysis of transformer with neutral resistor and plotted the inrush peak for its different values. They also formulated optimal neutral resistor for mitigation of inrush current. 2. PROBLEM FORMULATION The inrush current has already been described in Chapter 1. This inrush current is very harmful for transformers. It can burn the transformer winding due to heating up of winding. When the transformers starts, high magnitude harmonics rich current generated in the transformer, this high current generated due to high flux in air gap in transformers. This high current heating up the winding and the dangerous situation can be created in the transformers [5].
Figure 1: Current waveform Figure 1 shows a general waveform with inrush current magnitude, peak current and steady state current. At the time of starting of electrical equipment large current get generated in the equipment and it is tries to
exceed the peak current. The main reason to generate the inrush current is flux. When a electrical equipment is de energized, some flux remain in the core or air gap of the equipment and when again energized the same equipment, the flux trying to reach beyond the maximum value of 2Φmax, it becomes constant but current is always proportional to flux so the current increased gradually and reaches 5 to 10 times greater than full load current of equipment [6]. When transformer energized, several currents flows in transformer which are shown in figure 2. Current 1 is peak current, current 2 is large pulse width current and current 3 is mal functioning current. Peak current is the current which is maximum value of current either positive or negative direction of the transformer. Large pulse width current has large value of width in each steps of sinusoidal wave. Mal function current is generated by inrush phenomena. It can also call as false function current.
Figure 2: Inrush current waveforms [6]
Figure 3: Flow chart to differentiate the inrush current ISBN-978-81-932091-2-7
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Figure 3 shown the flow chart of differentiate inrush current. As the transformer re energized, current will flow in the primary core of transformer. The value of current (magnitude and phase ) is measured by current transformer , which discriminate between normal current and fault current. In next step, preset value compare the current with calculated value and 1st and 2nd harmonics are also calculated in the calculated current. If 1st and 2nd harmonics are present with large value in the current, it shows that inrush current is present and if both harmonics absent which means there are internal or external faults are present in the transformer. Both, the magnitude and presence of harmonics are decide about the next step to protect the transformer. If there is inrush current or external fault present, the transformer do not trip but if there is internal fault present, the transformer will trip immediately. For the next samples, this process repeat again and again. 3. REDUCTION TECHNIQUES There are many methods to mitigate inrush current like injection of resistor in system, injection of voltage by Pulse Width Modulation, Point on Wave switching (POW). This Chapter describes a new method to mitigate inrush current which called prefluxing and modeling to mitigate inrush current with using prefluxing. A filter is also used in prefluxing device to control the harmonics in power transformer. The prefluxing technique is the combination of POW prefluxing device and filters. In recent years, various protection systems for transformers based on the differential relaying were developed. Various techniques based on complex circuit or microcomputers are proposed to distinguish inrush current fault current. However, the transformer still must bear with large electromagnetic stress impact caused but the inrush current. The main factors affecting the magnetizing inrush current are POW voltage at the instant of energization, magnitude and polarity of residual flux. Total resistance of the primary winding, power source inductance, air core
inductance between the energizing winding and the core, geometry of the transformer core and the maximum flux carrying capability of the core material. From past years many techniques have used to mitigate inrush current for example point on wave switching, pre insertion of resistance in primary of transformer, injection of voltage in tertiary winding etc. 4. MITIGATION OF INRUSH CURRENT IN THREE PHASE POWER TRANSFORMER USING PREFLUXING A MATLAB Simulink model has prepared for simulation study. Here three phase power transformers having a rating of 250 MVA, 11/400 KV, 50 Hz, connected to a supply source as shown in Figure 4. This model used prefluxing technique to mitigate inrush current and harmonics. Current and flux measurement devices are connected whose results are also shown in next section. The core is used with specific initial fluxes and saturation limit. Some amount of flux provides in each phase to get the value of inrush current. When the power transformer energized, the flux of all three phases will increase and reach till the maximum value of flux. And after that maximum value of flux will become saturated and drawn more inrush current from source, which may be 5 to 10 time greater than rated current. The main reason of saturation of flux is due to residual. Residual flux is nothing but it is some amount of flux which remains in the core at the time of de energisation of transformer. Residual flux is depending on the rating of power transformer and at the instant on which transformer is deenergizing. It will have different value for different rating transformer. MATLAB Simulink model shown in figure. 5. SIMULATION RESULTS Prefluxing technique is used to reduce the effect of inrush current and harmonics till 99%. The prefluxing technique discussed in Chapter 4 and the result of transformer after using prefluxing is shown under: Mitigated Current: Figure shows the current after using prefluxing technique on ISBN-978-81-932091-2-7
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transformer. The inrush current goes down 99 % by this technique.
Flux: Flux of all three phases shown in figure 5 (D) This flux is unsaturated flux.
Figure 5 (A) Mitigated current in phase A. Figure 5 (A) shows the mitigated current in phase A. the magnitude of current is 46 Amp which is normal for transformer while without using any technique the current in phase A was 1700 Amp.
Figure 5 (D) Flux of compensated system Harmonics: By using prefluxing technique and filter, the harmonics eliminate from the system. Figure 5 (E) shows the harmonics in phase A, phase B and phase C.
Figure 5 (B) Mitigated current in phase B Figure 5(B) shows the mitigated current in phase B the magnitude of current is 47 Amp This is normal for transformer while without using any technique, the current in phase B was 1425 Amp.
Figure 5 (C) Mitigated current in phase C Figure 5.(C) shows the mitigated current in phase C the magnitude of current is 46 Amp This is normal for transformer while without using any technique the current in phase C was 410 Amp.
Figure 5 (E1) Harmonics in phase A Figure 5 (E1) shows the harmonic in phase A. Total harmonic distortion (THD) in phase A is 0.04 %, while THD without using prefluxing is 25.78%. So this technique reduces harmonics 99 %. Fundamental component as figure 5.5 is 0.07 and second harmonic is 0.028
Figure 5(E2) Harmonics in phase B Figure 5(E2) shows the harmonic in phase B. Total harmonic distortion (THD) in phase B is 0.02 % while THD without using prefluxing is 39.12 %. So this technique reduces harmonics 99 %. Fundamental ISBN-978-81-932091-2-7
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component as figure 5.6 is 0.0012 and second harmonic is 0.014.
Figure 5 (E3) Harmonics in phase C Figure 5(E3) shows the harmonic in phase B. Total harmonic distortion (THD) in phase B is 0.02 % while THD without using prefluxing is 81.38 %. So this technique reduces harmonics 99 %. Fundamental component as figure 5.7 is 0.0016 and second harmonic is 0.013. Table 5.1 Comparison between SSSC and prefluxing technique to mitigate inrush current Phas es
A B C
Without using any mitigation technique Curr Harmon ent ic
Using SSSC Curr ent
Har mon ic
190 0 142 5 410
25.78
190
39.12
58
81.38
60
17.2 6 28.6 0 22.6 7
Using prefluxing technique Curre Har nt mon ic 46
0.04
47
0.02
46
0.02
As shown by table 5.1, prefluxing technique is far better than SSSC. Prefluxing technique not only mitigates inrush current in transformer but also it eliminates harmonics. SSSC technique can mitigates only 80 percent of inrush current while prefluxing mitigates 98 percent of inrush and harmonics. As shown in above table, there is 1900 Amps of inrush current in phase A which is mitigated by SSSC till 190 Amps while prefluxing mitigated same current till 46 Amps which is almost negligible. The same case can be shown in another two phases, phase B has 1425 Amps current which mitigated 58 Amps by SSSC and 47 Amps by prefluxing and in phase C, generated 410 Amps current which is mitigated till 60 Amps by SSSC and 46
Amps by prefluxing. So the conclusion is that, prefluxing technique is not only economic but also it is very efficient for covering the purpose completely. 6. CONCLUSION The main purpose of this thesis is to mitigate the inrush current and harmonics which is generated in three phase power transformer. This inrush current is very harmful for transformer. The effect and factors of inrush current on power transformer is also described in this thesis. In this thesis, we have investigate inrush current, harmonics, voltage and flux by using MATLAB®/simulink model and find the high magnitude starting current and total harmonics distortion in transformer . In this thesis, we have introduce a new technology to reduce the inrush current and harmonics that is called prefluxing technology. This prefluxing is a device which is made by charged capacitor and converter. There are many methods to reduce high starting current and harmonics but all methods reduce only 70% to 80 % starting current and harmonics but in this research, we have reduce 95 % of starting current and harmonics. 7. FUTURE SCOPE The proposed prefluxing device can replace filter popularly used for harmonics mitigation. It reduces the cost of the system satisfactory extent. This prefluxing device is cheaper in comparison to power electronics compensation devices like SSSC, DVR, UPFC etc to improve stability of system. REFERENCES 1. Gaowa Wuyun ,Po Li and Dichen Liu, “Phase Control to Eliminate Inrush Current of Single-phase Transformer by Using Approximate Calculation of Residual flux” IEEE 2006 2. A.M. Miri, C Muller, C Sihler, “Modelling of Power Transformers by a detailed magnetic equivalent circuit” Researchgate publication 228429082. 3. Kunal J Patel, “Effect of Transformer Inrush Current” thesis, University of Southen Queen land , PP 2539. ISBN-978-81-932091-2-7
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4. John H. Brunke, Klaus J. Fröhlich, Senior Member, IEEE, “Elimination of Transformer Inrush Currentsby Controlled Switching—Part II: Theoretical Considerations” IEEE, vol. 16, April2001. 5. Ramsis S. Girgis, Ed G. Tenyenhuis, Member, IEEE, “Characteristics of Inrush Current of Present Designs of Power Transformers” IEEE, 2007. 6. Hongkui Li1, Yan Li, Xi Sun, DongxuLi,Youteng Jing, “Analysis of ThreePhase Power Transformer Windings Forces Caused by Magnetic Inrush and ShortCircuit Currents” IEEE, Sept.2009. 7. Salman Kahrobaee, Marcelo C. Algrain, SohrabAsgarpoor, “Investigation and Mitigation of Transformer Inrush Current during Black Start of an Independent Power Producer Plant, Energy and Power Engineering, 2013 8. Mukesh Nagpal, Terrence G. Martinich, Ali Moshref, Kip Morison, and P. Kundur, “Assessing and Limiting Impact of Transformer Inrush Current on Power Quality” IEEE transaction, vol. 21, April 2006. 9. Juei Lung Shyu, “A Novel Control Strategy of Reduce Transformer Inrush Current by Series Compensation” IEEE2005 10. Abbas Ketabi, Ali Reza HadidiZavareh, “New Method for Inrush Current Mitigation Using Series VoltageSource PWM Converter for Three Phase Transformer” IEEE2011.
11. L.Jebaraj and N. Muralikrishnan, “DE Algorithm based Comparison between Two Different Combinations of FACTS Devices under Single Line Outage Contingency Conditions” IEEE 2012. 12. Saidi Amara and Hadj Abdullah Hsan, “ Power System Stability improvement by FACTS device: A comparison between STATCOM, SSSC and UPFC” IEEE 2012. 13. Sandeep Tripathi, R.K Tripathi, “ Voltage Stability Improvement in Power System using FACTS Controller: States of ArtsReview” IEEE2010. 14. Li Wang, Quang Son Vo, “ Power Flow Control and Stability Improvement of Connecting an Offshore Wind Farm to a One –Machine Infinite bus System Using a Static Synchronous Series Compensator” IEEE 2013. 15. Alex Reis, Jose C. de Oleveira, Roberto Apolonio, Herivelto S. Bronzeado, “ A Controlled Switching methodology for Transformer inrush Current Elimination: Theory and Expermrimental Validation” IEEE Oct2011 16. Douglas I. Taylor, Joseph D. Law, Brian K. Johnson and Normann Fischer, “SinglePhase Transformer Inrush Current Reduction Using Prefluxing” IEEE, January 2012. 17. V. Oiring de Castro Cezar, LL. Rouve, JL. Coulomb, FX. Zgainski, O. Chadebec, and B. Caillault, “Elimination of inrush current using a new prefluxing method. Application to a single phase transformer” IEEE2014
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Analysis of Solar Thermal Cooling System Using TRANSOL Khagendra Kumar Upman*, Deepak Goyal, Dhawal Vyas, Navneet Sharma B.L.Gupta* Government Engineering College Bharatpur Rajasthan.
*Corresponding Author email: kha16gietupman@gmail.com,blgbharatpur@gmail.com Abstract: This paper covers the performance analysis of solar thermal cooling system for a computer laboratory situated in Government Engineering College Bharatpur using Flat Plate Collector, Evacuated Tube Collector and Compound Parabolic Collector. The computer lab has the floor and roof area 198.55 m2. The peak cooling load is calculated and it is 34.94 kW, accordingly 10TR vapor absorption cooling system was adopted. The 10 TR vapour absorption system was operated by a field of collector area varying from 80-120 m2..The other parameters like hot storage tank, cold storage tank, pump, cooling tower etc are used. The simulation was carried out on TRANSOL Program for Bharatpur city situated in east of Rajasthan (INDIA). It can be conclude that solar thermal cooling system is technically feasible because it offers good solar fraction in the range of 0.52-0.75. The primary energy savings reaches up to 52%. Keywords—Solar Thermal System, TRANSOL, Solar Fraction, Primary Energy , 1.Introduction Because of global warming, increased energy need, limited resources and environmental pollution there is dire need for development of such technologies that can offer decrease in energy consumption, peak electrical demand, and energy costs without lowering the desired level of comfort. That can also significantly reduce the emission of CO2 because buildings use around 50% of the total energy consumption in developed countries. In place of the use of electricity in conventional cooling systems, solar thermal cooling systems use solar heat to produce refrigerating effect. In such systems the phenomenon of sorption: the process by absorption liquid-gas and the process by adsorption solid gas are utilized to produce the refrigeration effect. A solar electric refrigeration system consists mainly of photovoltaic panels and an electric refrigeration device based on vapor compression system. Photovoltaic panels consist of solar cells which are basically made of semiconductor materials that convert the incident solar radiation into direct current. This direct current may be directly used to drive the DC compressor or may be converted into AC to drive the conventionally used AC compressor. Using solar panels for refrigeration has many advantages. They are simple, compact in size, high power to weight ratio and have no moving parts. In this system solar panel drive the DC
motor of the compressor for producing the cooling effect in the evaporator by absorbing
Fig. 1 Vapour Absorption System heat and rejecting heat to the ambient by the condenser. In the vapour absorption systems, a pair of substances having the strong affinity to form a solution is utilized. Among the pair of substances, the substance having lower boiling temperature is called refrigerant and the other is called absorbent. Solar thermal collector is used to supply low grade heat input in the generator. Cooling is produced in the evaporator and heat is rejected from the condenser and the absorber. H2O-LiBr and NH3-H2O are the two major working pairs used in the absorption system. In the water lithium bromide pair H2O works as ISBN-978-81-932091-2-7
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the refrigerant and other is the absorbent while in the ammonia H2O pair ammonia works as the refrigerant and water is the absorbent. Currently, various absorption machines with COPs ranging from 0.3 to 1.2 are available. For double-effect LiBr-water chillers with COPs around 1.2 are available for air conditioning which use solar collector capable of working at 150°C but the costs of these systems are high. Less expansive collectors can be used for single effect LiBr-water absorption machine. 2. Methodology Adopted: The whole work is divided into three phases. First phase is related to defining a building for carrying out the analysis. The building has a floor area of 198.55 square meters. Parameters such as construction detail, occupancy, lighting load, ventilation, infiltration are defined as per utilization of existing building of computer lab situated at Govt. engineering college Bharatpur. The cooling load of the building is determined by using calculation for sensible cooling load and latent cooling load. Details of heat gain, with respect to source, such as wall conduction, reflection, direct solar heat gain etc are taken. In the second phase according to the cooling load of the building the component sizing for solar thermal cooling system is carried out. The building simulation of solar thermal cooling system is done in the program TRANSOL 3.1 (software for simulating thermal solar cooling systems) by taking suitable component and their size. Based on the results given by the program’s key parameters, solar fraction, primary energy savings, electrical (Grid) COP and paybacks are calculated for solar thermal cooling systems. Finally in the last phase conclusion is made on the behalf of paybacks whether the system was adopted for the existing building or not. Laboratory is scheduled from 9 AM to 6 PM from Monday to Saturday and Sunday is holiday. Total room sensible heat = 1.115 x total sensible heat gain from all sources = 24.93 kW Total room latent heat = 1.06 x total latent heat gain from all sources = 10.01 kW
Therefore, total cooling load = 10.01 + 24.93 = 34.94 kW. 3 Modelling and Simulation In the present work modelling and simulation of small scale solar cooling systems is carried out using TRANSOL program. The program TRANSOL EDU 3.1 is used for the simulation of a solar thermal cooling system. The simulation is carried out for a computer lab used in day time only and which is considered to be in situated at Govt. engineering college Bharatpur in India an Asian country. The solar analyzed thermal cooling system is composed of a solar collector field (Solar collector), hot storage tank (HST), cold storage tank (CST) and vapour absorption chiller (VAC). Three different types of collectors are considered in this study flat plate, evacuated tube and compound parabolic. The solar collector captures the energy from the sun and supplies energy to a hot storage tank through an external heat exchanger. A 35 kW capacity vapour absorption chiller (VAC) is selected which have the COP 0.7 and pump power consumption of 210W. A cooling tower of 90 kW capacities is selected because the generator capacity of VAC is 50 kW and heat rejection in the condenser is 90 kW. A hot storage tank of 5000 litres and a cold storage tank of 1000 litres are used. The wide variance of collector area 80-120 m2 is taken with an interval of 10 m2. Two pumps are used in the solar collector loop, one is to circulate hot working fluid from solar collector to heat exchanger, and another to circulate fluid between heat exchanger and hot storage tank. These pumps (P1, P2) are known as primary and secondary pump respectively and operated by control strategy depending on solar radiation intensity. The flow rate of pump is constant. The system stops the pumps if the temperature in the hot storage tank exceeds the maximum security value. A vapour absorption machine (VAM) is directly connected to the hot storage tank, this machine is turned on when cooling is required and the temperature of the solar tank is over a set point temperature. The heat coming from the absorber and condenser is released by cooling tower controlled by a variable frequency drive that increases energy efficiency and reduces ISBN-978-81-932091-2-7
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electrical energy consumption. The cold water coming out from the evaporator of vapour absorption machine is stored in the cold storage tank (CST). An electrical operated compression cooling machine is used as a backup in order to cover complete cooling demand of the building. This compression based cooling machine is operated only when the cooling demand is in building and the temperature of the cold storage tank is below than the specified set point temperature.
Fig. 7 shows that comparison of solar fraction for different three types of collector i.e FPC/ETC/CPC and shows that the using CPC solar fraction is highest.
Fig. 4 Solar Fraction for FPC
Fig. 2 Solar Thermal Cooling System 4. Simulation Results: In this paper we have analyzed and compared performance of solar thermal cooling system using 3 types of solar collector. These collectors are: Flat plate collector (FPC), Evacuated tube collector (ETC) and Compound parabolic collector (CPC). Simulation is performed to find out some performance metrics like Annual net collector efficiency, solar fraction and Specific net collector output for each collector. Simulation results are as follows:
Fig. 3 Net Collector Efficiency for FPC
Fig. 5 Solar Fraction for ETC
Fig. 6 Solar Fraction for CPC ISBN-978-81-932091-2-7
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Fig. 7 Comparison of Solar fraction for each collector 5. Conclusion: Referances: 1. ASHRAE, Handbook of fundamentals, 1997,2009. 2. Climatech Aircon Engineering Pvt. Ltd. Jaipur Jaipur. 2014 “Quotation for supplying the packaged air conditioner and pumps” at Government Engineering College Bharatpur (Raj.) India. 3. Duffie J.A., Backman W.A. 2006 “Solar engineering of thermal process” Third edition Published by John Wiley & Sons Inc, Hobokan New Jersey. 4. Eicker U., Colmenar-Santos A., Teran L., Cotrado M. 2014 “Economic evaluation of solar thermal and photovoltaic cooling systems through simulation in different climatic conditions: An analysis in three different cities in Europe” Energy and Buildings, Vol. 70, pp. 207-223. 5. TRANSOL http://aiguasol.coop/en/transol-solarthermal-energy software. 6. Tsoutsos T., Aloumpi E., Gkouskos Z., Karagiorgas M. 2010 “Design of a solar
This study covers the performance analysis of solar thermal cooling system for a computer lab situated in government engineering college Bharatpur using FPC, ETC and CPC. The computer lab has the area 198.55 m2 .The peak cooling load is 34.94 kW accordingly 10TR vapour absorption cooling system was adopted. The 10 TR vapour absorption system was operated by a field of collector area varying from 80-120 m2.. The solar fraction is highest for the CPC type collector and lowest for the FPC. The highest solar fraction has been observed as 0.63, 0.72, 0.73 for FPC/ETC/CPC for the collector area range in 80-120 m2. At high collector area the collected heat is increased in all the type of collector but in the case of ETC and CPC the heat losses also increase. absorption cooling system in a Greek hospital” Energy and Building, Vol.42, pp. 265-272. 7. Gupta, B.L., 2015. “Technoeconomic comparision of small scale solar thermal and photovoltaic cooling system” Ph.D thesis MNIT Jaipur. 8. Henning H.M. 2007 “Solar assisted air conditioning of buildings – an overview” Applied Thermal Engineering, Vol. 27, pp. 1734–1749. 9. Kim D.S., Infante Ferreira C.A. 2008 “Solar refrigeration options – a state-ofthe-art review” International Journal of Refrigeration Vol. 31, pp. 3–15. 10. TRANSOL http://aiguasol.coop/en/transol-solarthermal-energy software. 11. Tsoutsos T., Aloumpi E., Gkouskos Z., Karagiorgas M. 2010 “Design of a solar absorption cooling system in a Greek hospital” Energy and Building, Vol.42, pp. 265-272.
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Analysis and Modeling of AC-DC Buck Converter Using PFC Control Technique Gaurav Vijay1,*, D.K.Palwalia2 Department of Electrical Engineering, Rajasthan Technical University Kota, India Corresponding Author: gvijay.mtech@rtu.ac.in
Abstract This paper presents non-isolated single-phase AC-DC buck converter which are used for improving power quality at AC mains input source which improves power factor. The AC-DC converters convert to regulate supply process which injects harmonics distortion and waveform at input AC source. This AC-DC buck converter are used with PFC based technique. This technique reduces the input current harmonics and improves power quality. The main objective of this paper is to obtain a unity power factor and a constant DC output voltage. Here, a source conditioning based design of these converter is demonstrated and a comparison of with and without source conditioning based converter is shown. The operation and simulation results obtained by the proposed source conditioning scheme, with the help of MATLAB/Simulink that verifies the design. Keywords—Buck Converter; Proportional Integral(PI); Without PFC Technique; With PFC Technique. INTRODUCTION Now a day, it is generally the AC-DC converters are widely used in low power applications. The power electronics application is to convert the electric power available from a power source into the form which is best suited for user loads. Some types of power converters are required to interface between power source and load to achieve this objective. Hence, the converters may be AC-DC, DC-DC, AC-AC, DC-AC [1], with or without transformer isolation depending on the load. The conventional power factor correction(PFC) converters can achieve close to unity power factor, low total harmonic distortion(THD) and constant output voltage. In this block diagram single phase AC source is feed to the diode bridge rectifier. It is convert AC power into DC power but it is unregulated power. This unregulated power is to convert regulated DC power by using control DC-DC converter[2-4].
I.
Single Phase AC Source
Uncontrolled Diode Rectifier
Filter Capacitor
DC (unregulated)
DC-DC Converter
DC (unregulated)
Load
DC (regulated)
Controller
Fig. 1. Block diagram of AC-DC Converter DC-DC converters are the electronic devices used to change DC electrical voltage
efficiently from one level to another. These converters required because unlike AC, DC cannot be simply stepped up or down using a transformer. In many ways, a DC-DC converter is the DC equivalent of a transformer. These converters are widely applicable in different areas like, where 24V to be stepped down from a truck battery to 12V DC to operate a radio, transceiver or mobile phone. The DC-DC converter includes various topologies such as Buck converter, Boost converter, BuckBoost[5] and Cuk converter. To improve the power factor in the buck converter topology. There are two types of PFC methods as passive method and active method. The active PFC method is used recently in most of the electronic components. Power conditioning techniques like PFC and harmonic filtration is used to reduce in the circuit THD[6]. The AC-DC buck converter is probable by using typically diode bridge rectifier(DBR) circuit[7-9]. The use of diode rises the nonlinearity of the system as the diode is considered as nonlinear load. Non-linear loads generally do not cause reactive power to flow at the fundamental line frequency. They can, however, draw higher RMS currents and hence add to distribution system losses for a given load. The non-linear nature of these loads then draws non-pure sine wave currents thus causing harmonics of the fundamental current to be ISBN-978-81-932091-2-7
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present. Since harmonic distortion is caused by freewheeling diode. The switching network non- linear elements connected to the power made up of the transistor and the diode â&#x20AC;&#x2DC;chopsâ&#x20AC;&#x2122; system, any device that has non-linear the DC input voltage VDC and therefore the characteristics will cause harmonic distortion. converter is known as â&#x20AC;&#x2DC;chopperâ&#x20AC;&#x2122;, which The power quality issue will increase[10-12]. produces a decrease average output voltage. This converter is used to convert the input The switching frequency fs = and the duty side AC supply to a regulated DC output. This cycle is â&#x20AC;&#x201C; converter produces supply pollution and makes đ??ˇ= = = đ?&#x2018;&#x201C;đ?&#x2018;Ą (1) source current nonlinear as, the source current ( ) L in this converter infects the input current S harmonics, ripple and THD[13-15]. The rapid increase in deployment of such converter expressively increase the problem. In order to + achieve the conversion of AC-DC, two stages VDC + C RL DM are used. First stage is a DBR which provide Vo AC-DC conversion and the second is a DC-DC converter[16-18]. This complete system through its operation gives desired output but along with that, the input side line current harmonics, ripple and THD are high. Fig. 2. Equivalent Circuit for PWM buck In these source current harmonics, ripple is Converter condensed by PFC control technique[19-22]. B. Design Oriented Analysis of Buck Converter This control technique requires two control The calculation of buck converter where loops which are essential with the outer loop V = 24V, Vo = 12V, Io = 0.8616A, RL = 13.9đ?&#x203A;ş, DC named as voltage loop controller and inner loop ripple voltage Vr (1% of Vo) = 0.12V, ripple is PWM current loop controller. Some other current â&#x2C6;&#x2020;iL = 1.72A, switching frequency fs = word control technique is used to control 100kHz. and the other parameter is listed Table inductor current include peak current control, I is given as follows â&#x20AC;&#x201C; average current control, hysteresis control and border line control[23-26]. Normally, direct Duty ratio: current output voltage of the converters in the đ??ˇ= (2) system output is used as feedback loop as outer closed loop control and different control Output power: systems such as proportional-integral đ?&#x2018;&#x192; =đ?&#x2018;&#x2030; đ??ź (3) Inductor L: controller, proportional-integral-derivative ( ) controller, sliding-mode-control are providing đ??ż= (4) to fast dynamic response[27-30]. Capacitor C: II. SYSTEM CONFIGURATION C= (5) A. Analysis of PWM Buck Converter Ripple Current â&#x2C6;&#x2020;iL: A buck converter is a step-down converter ( ) where the output DC voltage which is lower â&#x2C6;&#x2020;đ?&#x2018;&#x2013; = (6) than the input voltage. It has the advantages of ESR rC: simplicity and low cost. A PWM DC-DC buck đ?&#x2018;&#x; = (7) â&#x2C6;&#x2020; converter is a combination of diode, inductor TABLE I. PARAMETER FOR BUCK CONVERTER and MOSFET switch. Here MOSFET works as TOPOLOGY a switch and itâ&#x20AC;&#x2122;s on and off control depends on Parameter Values PWM signal. Filtering capacitor with equivalent Input Voltage VDC 24 V series resistance(ESR) is also required to the Output Voltage VO 12 V output of the converter to decrease output voltage ripple. The diode DM is known as Duty Ratio D 0.5 ISBN-978-81-932091-2-7
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Parameter Values Input Voltage VDC 24 V Output Voltage VO 12 V Inductor L 34.75 ÂľH Capacitor C 35.83 ÂľF ESR rc 69.76 mđ?&#x203A;ş Output Power PO 10.3 W III. PROPORTIONAL-INTEGRAL CONTROL STRATEGY In order to control and regulate the output DC voltage at desired level, against input voltage and load variation, a fast and reliable closed loop controller is essential to sustain the steady as well as dynamic performance of system. The voltage error Ve is calculated from the difference between the reference voltage V* and the output DC voltage Vo as â&#x20AC;&#x201C; đ?&#x2018;&#x2030; = đ?&#x2018;&#x2030;â&#x2C6;&#x2014; â&#x2C6;&#x2019; đ?&#x2018;&#x2030; (8)
V* -
ď&#x192;˛
Integral Gain
Limited Integrator
+
â&#x2C6;&#x2018; +
I
Ve
â&#x2C6;&#x2018;
+
KI
based AC-DC buck converter only one control loop which is voltage loop like PI controller is required. In this PI controller the output voltage is taken as a reference signal. This reference signal is compared with a constant to generate voltage error signal, this voltage signal is feed to PI controller and output of this controller is compared with triangular pulse. The output signal of relational operator is PWM signal that is feed to the switch. L
S D1
D3 C
DM
VS D4
RL
D2
PWM Controller
PI Controller
Ve
ď&#x20AC; +
V*o
Fig. 4. AC-DC without PFC based Buck Converter
Vo
KP Proportional Gain
Fig. 3. Schematic of Proportional-Integral(PI) Controller The output DC voltage Vo is fed to error amplifier to produce error signal Ve proportional to the subtracted value of Vo from reference set point value V*. The error signal Ve is feed to PI controller. The transfer function of PI controller is as â&#x20AC;&#x201C; đ?&#x2018;&#x2021;đ??š(đ?&#x2018; ) = đ??ž + (9) IV. MODES OF OPERATION AND SIMULATION RESULTS A. Without PFC Based Buck Converter In AC-DC buck converter without power factor correction technique, only one control loop is required. The single phase without PFC based AC-DC diode bridge rectifier is shown in Fig.4. that converts into regulated DC supply by using DC-DC buck converter. Without PFC
Fig. 5. Simulation results of input, output voltage and input current waveforms without PFC based Buck converter ISBN-978-81-932091-2-7
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Fig. 6. FFT analysis of without PFC based Buck converter
Fig. 8. Simulation results of input, output voltage and input current waveforms with PFC based Buck converter
In order to achieve the conversion of AC-DC, a DBR is used which provides desired DC output. The input line current harmonics are analyzed using FFT tool and the total harmonic distortion is shown in Fig. 6. The THD in input side line current is 46.71% which is quite high and power factor is 0.63. B. With PFC Based Buck Converter The single-phase AC-DC diode bridge rectifier with PFC based buck converter is shown in Fig.7. With PFC based AC-DC buck converter, there are two control loops which are essential with the outer loop named as voltage loop controller. L
S D1
In voltage loop controller the voltage error signal is processed through the PI controller to get desired control signal. The voltage error signal is generated by output voltage and reference voltage. This PI controller signal is product of the unit template of AC supply voltage and the product signal is compared by actual DC current signal. The compared signal is amplified by gain and compared with triangular pulse and the output signal of relational operator is PWM signal that is feed to the switch. The inner loop known as PWM current loop controller.
Idc
D3
+ DM
VS
C
RL
Vo -
D4 D2
VS
Ref. Current Generator
I*dc
+
PWM Controller PI Controller
Ve +
V*o
Fig. 7. AC-DC with PFC based Buck Converter
Fig. 9. FFT analysis of with PFC based Buck converter ISBN-978-81-932091-2-7
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The source current as shown in Fig. 8. is analyzed for harmonics using FFT tool. The FFT analysis of source current as depicted in Fig. 9. demonstrates that the THD in case of PFC based buck converter which is reduced to 9.16%. The input voltage and current waveforms are in same phase that shows improved power factor is 0.98 and the comparison of with and without PFC Controller can be listed in Table II. TABLE II. COMPARISON OF WITH AND WITHOUT PFC CONTROLLER MODE Modes of Operation Paramet Without PFC With PFC er Controller Controller % THD 46.71 9.16 Power 0.63 0.98 Factor V. CONCLUSION This paper describes power quality improvement of AC-DC buck converter using PFC based technique. The power quality issue not only refers to the good quality of power but also to the input parameters which affect the output of the system. To improve the source current characteristics, a conditioning technique is required. Two kinds of control loop are used voltage loop control and PWM current loop control. The source conditioning scheme is simulated for buck converter. The simulation results show that, with the proposed source conditioning method the THD is reduced to 9.16% and this decrease in the harmonic content shows that the PFC based buck converter is working efficiently and also makes the input voltage and current waveforms are in same phase that shows power factor is improved to 0.98 which is useful to increase the efficiency of the system.
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[10] Y. Jang and M. M. Jovanović, "Bridgeless high-power-factor buck converter," IEEE Transactions on Power Electronics, vol. 26, pp. 602-611, 2011. [11] A. F. de Souza, D. C. Pereira, and F. L. Tofoli, "Comparison of control techniques used in power factor correction rectifiers," in Power Electronics Conference and 1st Southern Power Electronics Conference (COBEP/SPEC), 2015 IEEE 13th Brazilian, 2015, pp. 1-6, 2015. [12] L. Huber, L. Gang, and M. M. Jovanovic, "Design-oriented analysis and performance evaluation of buck PFC front end," IEEE Transactions on Power Electronics, vol. 25, pp. 85-94, 2010. [13] R. Ramesh, U. Subathra, and M. Ananthi, "Single phase AC-DC power factor corrected converter with high frequency isolation using buck converter," International Journal of Engineering Research and Applications, vol. 4, no. 3, pp. 79-82, 2014. [14] Y. Dagur and D. M. K. Gupta, "Single Phase AC-DC Converter Employing Power Factor Correction with High Frequency Isolation Using Buck-Boost PWM Converter," International Journal of Innovative Research in Science Engineering and Technology, vol. 4, pp. 11, 2015. [15] W. Wei, L. Hongpeng, J. Shigong, and X. Dianguo, "A novel bridgeless buck-boost PFC converter," in Power Electronics Specialists Conference, 2008. PESC 2008. IEEE, 2008, pp. 1304-1308, 2008. [16] M. Junaid and B. Singh, "Analysis and design of buck-boost converter for power quality improvement in high frequency on/off-line UPS system," in Power Electronics, Drives and Energy Systems (PEDES), 2014 IEEE International Conference on, 2014, pp. 1-7, 2014. [17] D. Cortés, J. Alvarez, and J. AlvarezGallegos, "Feedforward and feedback robust control of the buck converter," IFAC Proceedings Volumes, vol. 35, pp. 313-318, 2002.
[18] Y. Zhou and B. Wang, "A large signal dynamic model for buck-cascaded BuckBoost converter in universal-input PFC applications," in Electrical Machines and Systems, 2008. ICEMS 2008. International Conference on, 2008, pp. 4080-4085, 2008. [19] K. Arora, S. Katiyar, and R. Patel, "Design and analysis of AC to DC converters for input Power Factor Correction," in Applied and Theoretical Computing and Communication Technology (iCATccT), 2016 2nd International Conference on, 2016, pp. 171-176, 2016. [20] J. Yang, W. Zhang, F. Al-Naemi, and X. Chen, "A high power factor rectifier based on buck converter operating in discontinuous inductor current mode," Energy and Power Engineering, vol. 5, pp. 842-849, 2013. [21] G. Vijay and D.K.Palwalia, "A Novel Analysis and Modeling of Boost And Buck Converter," International Journal of Electronics, Electrical and Computational System, vol. 6, no. 3, pp. 239-243, 2017. [22] J. Mahdavi, A. Emadi, and H. Toliyat, "Application of state space averaging method to sliding mode control of PWM DC/DC converters," in Industry Applications Conference, 1997. ThirtySecond IAS Annual Meeting, IAS'97., Conference Record of the 1997 IEEE, 1997, pp. 820-827, 1997. [23] S. K. Sharma, D. K. Palwalia, and V. Shrivastava, "Analysis of boost converter with input source power conditioning," in Power Electronics, Intelligent Control and Energy Systems (ICPEICES), IEEE International Conference on, 2016, pp. 15, 2016. [24] R. Kumawat and D. Palwalia, "A novel PWM control for asymmetric multilevel inverter based on half bridge module," in Power India International Conference (PIICON), 2016 IEEE 7th, Bikaner, India, 2016, pp. 1-5, 2016. [25] D. K. Palwalia and S. P. Singh, "Digital Signal Processor-based Controller Design ISBN-978-81-932091-2-7
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and Implementation for Self-excited Induction Generator," Electric Power Components and Systems, vol. 36, pp. 1130-1140, 2008. W. Li and X. He, "Review of nonisolated high-step-up DC/DC converters in photovoltaic grid-connected applications," IEEE Transactions on Industrial Electronics, vol. 58, pp. 12391250, 2011. K. Matsui, I. Yamamoto, T. Kishi, M. Hasegawa, H. Mori, and F. Ueda, "A comparison of various buck-boost converters and their application to PFC," in IECON 02 [Industrial Electronics Society, IEEE 2002 28th Annual Conference of the], 2002, pp. 30-36, 2002. D. D. C. Pereira, M. R. Da Silva, E. M. Silva, and F. L. Tofoli, "Comprehensive review of high power factor ac-dc boost converters for PFC applications," International Journal of Electronics, vol. 102, pp. 1361-1381, 2015. M. H. Rashid, Power electronics: circuits, devices, and applications: ISBN 9788131702468 Pearson Education India, 2009. S. Singh, B. Singh, G. Bhuvaneswari, and V. Bist, "A Power Quality Improved Bridgeless Converter-Based Computer Power Supply," IEEE Transactions on Industry Applications, vol. 52, pp. 43854394, 2016.
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Architectural and Technical Approach for Self-Sustainable Building Kapil vyas1, Dilip Sharma2, Shivlal3 Student, Civil Engineering Department, GEC Banswara. 2,3 Assistant Professor, Civil Engineering Department, GEC Banswara. 3 Principal, GEC Banswara Corresponding Author: kapil.vyas28@yahoo.com, dilip17714@gmail.com 1 U.G.
Abstract Growth of population and demand in energy has leaded us to create and find new ways to quench our thirst for energy. By giving the solutions for energy demand the environment must not be on stake, fitting in architecture and building design to create a more greener and eco-friendlier as well as sustainable design to reduce the carbon per capita. Filling the blank new spaces created in the sustainable architecture has opened the ideas of eco-friendly and sustainable designs to carry our increasing demand of energy and comfort. Using sustainable architecture and technologies, and introducing the technology that uses the renewable source of energy and not depending on fossil fuels. Building architecture so as it can be self-sustained by its own renewable energy source. Keywords: Renewable Energy, Self-Sustainable Building, Solar, Wind, Biomass, Architectural Orientation. 1. Introduction Green buildings are becoming increasingly common for both residential and commercial structures. The high demand for green design integrates world consciousness for the environment and sustainability. In many cases green structures may provide a lower lifetime cost alternative to conventional building methods, but has a higher sustainability future if developed correctly and efficiently. Although green technology is more expensive than traditional technologies, it has the potential to have a shorter payback period due to significantly reduced utility bills. With the current economic condition, cost-effective designs will certainly drive the market forward. The idea of green design is still a new concept. Therefore, the definition of what is, and what is not green has sometimes been confusing. 2. Previous work study Shiv Lal et al. have studied that the residential and commercial buildings demand increases with rapidly growing population. It leads to the vertical growth of the buildings and needs proper ventilation and day-lighting. The natural air ventilation system is not significantly works in conventional structure, so fans and air conditioners are mandatory to meet the proper ventilation and space
conditioning. Globally building sector consumed largest energy and utmost consumed in heating, ventilation and space conditioning. This load can be reduced by application of solar chimney and integrated approaches in buildings for heating, ventilation and space conditioning. They concluded that it is a sustainable approach for these applications in buildings. The authors are reviewed the concept, various method of evaluation, modelings and performance of solar chimney variables, applications and integrated approaches. Peter et al. studied in their paper a conceptual framework aimed at implementing sustainability principles in the building industry. The proposed framework based on the sustainable triple bottom line principle, includes resource conservation, cost efficiency and design for human adaptation. Following a thorough literature review, each principle involving strategies and methods to be applied during the life cycle of building projects is explained and a few case studies are presented for clarity on the methods. The framework will allow design teams to have an appropriate balance between economic, social and environmental issues, changing the way construction practitioners think about the information they use when assessing building projects, thereby facilitating the sustainability of building industry. Grierson and Moultrie ISBN-978-81-932091-2-7
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worked in their research that the paradigm shift for sustainable buildings requires a transformation of the architectural design process. This paper examines how sustainability is embedded into design methodology and mapped onto, or has transformed, the design process. Interviews with a sample of Scottish architectural and multi- disciplinary practices were undertaken to explore the common approaches and barriers to sustainable design. Case study methodology was also employed to consider exemplar buildings and the value of postoccupancy evaluation is discussed. Within the context of the global environmental perspective, UK and Scottish legislation, sustainable principles and blueprints, a process model is developed to provide a framework for discussion and review. The first creative step is given as an alignment of practice ethos with established architectural philosophies and principles, from across the sustain ability spectrum, to move towards at ypology of sustain able building design. 3. The concept of “green” 3.1 Overview of “Green Concept” in Building Design There are large amounts of materials used and energy consumed during the construction and operation of an average building. The world’s population has grown exponentially since the Second World War, and there is currently pressure on available land and natural resources. As a society, we will eventually be faced with the depletion of our most widely used source of energy, the non- renewable fossil fuels. There are many ways in which these organizations are taking steps to reduce consumption such as developing new types of vehicles, energy sources, recycled materials, and designing environmentally friendly buildings. These environmentally friendly buildings are also known as “green” buildings. Example of Existing Green Building To illustrate the benefits of integrating green concepts in building design, construction and operation, a few examples of green buildings are provided. These examples also help to answer the question “what is a green building?”
The Chicago Centre For Green Technology (CCGT), Chicago, U.S.A. In 1999 the Chicago Department of Environment embarked on an ambitious project known as The Chicago Centre for Green Technology (CCGT). The Department gathered a team of architects and engineers who produced the final designs and oversaw the construction of a building that would serve as an example for companies and 7 homeowners all over North America.An amount of $5.4 million was spent renovating an existing two-storey, 40 000 ft2 building, that was to be converted into a green building. The project team incorporated many of the most advanced green technologies available at the time in the design of the CCGT. The idea was to design a building that would reduce the demand on natural resources and energy while decreasing the production of pollution and waste. The building was to do this without forcing occupants to change their habits drastically. The teams design focuses on four major areas: lighting, water, earth, and air. The following is a brief summary of the compilation of green technologies used in Chicago. Lighting Purpose: to reduce fossil fuel emissions released when electricity is produced. CCGT design includes: Photovoltaic cells. Passive light designs including a greenhouse with heat absorbing tiles and skylights. Smart lighting, which adjusts the electrical lights according to the available natural light, thus lowering electricity requirements. Motion-sensitive lights that turn themselves off when the room is empty. Water Purpose: To reduce pollution due to storm water runoff water and to reduce the demand on the municipal sewer system. CCGT design includes: Green roof (with succulent plant stores water in its roots and leaves and therefore does not need to be watered during drought) Cisterns (holding tanks used to collect rain water) ISBN-978-81-932091-2-7
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Disconnected downspouts (drain to soil not sewer) Bio swales (ditches with water-loving plants which filter pollutants) Earth Purpose: To reduce the demand on natural resources provided by such as oil, wood, and minerals. CCGT Design includes: Promotion of alternate forms of transportation by providing bike racks, showers, electrical outlets in the parking lot for electric cars, and close to major bus routes. Demolition waste was recycled when possible. Use of recycled materials in the furnishings in the building. Air Purpose: Reduce air pollution and the need for heating and cooling using non-renewable resources. CCGT design includes: A ground source heat pump and pipe system that carries a (non-toxic) liquid similar to antifreeze through a series of looped pipes 200 feet (61 m) below ground level. The liquid is used to regulate the temperature in the building. Highly effective insulation, including the green roof, that lowers heating and cooling costs. Use of natural gas to heat the building Use of local materials in the construction and operation of the building. This reduces pollution related to transportation and helps the local economy. Use of less harmful chemical products both for the construction and for the maintenance of the building. The green roof atmospheric carbon dioxide to oxygen through the natural process (photosynthesis) of the plant life. The roof also absorbs rainwater and thus reduces the amount of water released into the city’s sewer system. LEED and C2000 Rating systems LEED Accreditation In the United States the most prominent green building accreditation program is the
Leadership in Energy and Environmental Design (LEED) rating system. This is a program defining and rating green buildings. A Canadian equivalent rating system is currently under development. It is expected to focus on the same major areas that the LEED rating system does. These areas are: Sustainable Site Planning Safeguarding Water and Water Efficiency Energy Efficiency and Renewable Energy Conservation of Materials and Resources Indoor Environmental Quality The LEED rating system awards points for how a building’s design deals with specific solutions for the above-mentioned issues. The United States Green Building Council (USGBC) uses the LEED checklist to rate a building. Depending on the total points achieved for solutions related to the above areas, a rating for the building is awarded as follows: Certified 26-32 points Silver 33-38 points Gold 39-51 points Platinum 52-60 points Benefits The benefits of receiving a rating from LEED include increased publicity and promotion of high quality design. The rating also gives designers’ a method of comparing new designs to old designs in order to determine their success. Drawback Application for a LEED assessment costs the builder extra money and it does not change the building once it is built. 4. Self sustainable technologies 4.1 Smart Lighting/ Power Saving Electronics Simplest way to reduce energy is by using power saving electronics and smart lightings. These devices are designed to turn off when not in use. Smart lights contain photo sensors that read how much natural light is entering in the building and dim electric lights when there is enough natural light. Sometime smart lights ISBN-978-81-932091-2-7
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are equipped with motion detection sensors so as to automatically shut off the lights when no one is in the room. The major benefit of smart lighting and power saving electronics is that they reduce energy consumption. The reduction in energy implies reduced electricity costs. 4.2 Solar Water Heating Solar water heating panels are a system of uses glazed collectors that uses the sun's energy rather than electricity or gas to heat water. A solar water heater uses glazed collectors that are mounted on roof and is connected to storage tank. Fluid is pumped to the glazed collectors where it is warmed by the solar energy, and returned to a heat exchanger where heat from the fluid is used to heat the water. The water is then collected in an insulated water storage tank so as the water can be used when the sun is not shining. A typical system will provide 50% to 75% of the water-heating load.
Fig. 1: Solar Water Heating 4.3 Wind Turbine
Fig. 2: Wind Turbine Wind turbines are powered by the wind to produce energy. They do not use up natural
resources and do not produce greenhouse gases. They are an efficient, clean way to produce energy. Wind turbines are relatively low-cost. A 50-kW turbine will be enough to satisfy the daily energy need of a house. 4.4 Solar Panels Every building whether home, industry, institution or commercial establishment can generate some solar power by installing PV panels on the roof top. Sometimes this can be a BIPV (building integrated).
Fig. 3 : Solar Panels 4.5 Urban Bio Gas Plant Due to scarcity of petroleum and coal it threatens supply of fuel throughout the world also problem of their combustion leads to research in different corners to get access the new sources of energy, like renewable energy resources. Solar energy, wind energy, different thermal and hydro sources of energy, biogas are all renewable energy resources. But, biogas is distinct from other renewable energies because of its characteristics of using, controlling and collecting organic wastes and at the same time producing fertilizer and water for use in agricultural irrigation. Biogas does not have any geographical limitations nor does it require advanced technology for producing energy, also it is very simple to use and apply. Deforestation is a very big problem in developing countries like India, most of the part depends on charcoal and fuel-wood for fuel supply which requires cutting of forest. Also, due to deforestation It leads to decrease the fertility of land by soil erosion. Use of dung, firewood as energy is also harmful for the health of the masses due to the smoke arising from them causing air pollution. We need an ecofriendly substitute for energy. Kitchen waste is organic material having the ISBN-978-81-932091-2-7
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)” December 22-23, 2017 at GEC Banswara, www.apgres.in
high calorific value and nutritive value to microbes, that’s why efficiency of methane production can be increased by several orders of magnitude as said earlier. It means higher efficiency and size of reactor and cost of biogas production is reduced. Also, in most of cities and places, kitchen waste is disposed in landfill or discarded which causes the public health hazards and diseases like malaria, cholera, typhoid. Inadequate management of wastes like uncontrolled dumping bears several adverse consequences. It not only leads to polluting surface and groundwater through leachate and further promotes the breeding of flies, mosquitoes, rats and other disease bearing vectors. Also, it emits unpleasant odour & methane which is a major greenhouse gas contributing to global warming. Mankind can tackle this problem(threat) successfully with the help of methane, however till now we have not been benefited, because of ignorance of basic sciences – like output of work is dependent on energy available for doing that work.
Fig. 4: Urban Bio Gas Plant 5. CONCLUSION The motivation for this project stems from recent green trends. Green technologies are rapidly developing and readily available. Throughout each step of the design, the project focused on green alternatives to traditional construction practice. The goal of the project was to reveal the potential that sustainable living has to become standard practice. Overall, this was a very smooth transition, as early on it was decided that individuals would keep working with the sustainable elements they had
previously researched and would also take responsibility for those corresponding sections of the modelling tool. This personal maintenance of the basic knowledge of the systems being analyzed helped to save time and avoid confusion, as team members did not have to conduct a total handoff of information to someone unfamiliar with the characteristics of that sustainable element. The downside of this approach is that it kept information fragmented amongst group members. However, to address this issue and help maintain a cohesive analysis and report, team members adhered to a consistent schedule of weekly group meetings and maintained open lines of communication between meetings through the use of email and electronic databases such as Drop Box and Google Docs. References 1. Shiv Lal, S.C. Kaushik, P.K. Bhargav, (2013), “Solar chimney: A sustainable approach for ventilation and building space conditioning”, International Journal of Development and Sustainability, ISSN: 2168-8662, Volume 2 Number 1, Pages 277-297, ISDS Article ID: IJDS12110901. 2. Peter O. Akadiri, Ezekiel A. Chinyio, Paul O. Olomolaiye (2012), “Design of A Sustainable Building: A Conceptual Framework for Implementing Sustainability in the Building Sector”, Journal of Buildings, 2, 126-152, ISSN 2075-5309, doi: 10.3390/buildings2020126. 3. David Grierson, Carolyn Moultrie (2011), “Architectural Design Principles and Processes for Sustainability: Towards a Typology of Sustainable Building Design”, Design Principles and Practices: An International Journal Volume - 5, Number – 4, ISSN1833-1874. 4. Gan, G. (2011), “General expressions for the calculation of air flow and heat ISBN-978-81-932091-2-7
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transfer rates in tall ventilation cavities”, Building and Environment, Vol. 46 No. 10, pp. 2069-2080. 5. Macias, M., Gaona, J.A., Luxan, J.M. and Gomez, G. (2009), “Low cost passive cooling system for social housing in dry hot climate”, Energy and Buildings, Vol. 41 No. 9, pp. 915-921. 6. GRIERSON,D.2009, Towards Sustainable Building Design, Design Principles and Practices: An International Journal, Volume3, Number3, 2009, ISSN1833-1874. 7. LEED New Construction v,2,2 Reference Guide, Third Edition, US Green Building Council, Washington, DC 4. 8. LEED Home Reference Guide, US Green Building Council, Washington, DC 5. 9. LEED New Construction & Major Renovation Reference Guide, Version 2.2, Second edition September 2006, US Green Building Council, Washington, DC. 10. Renewable Energy: Wikipedia.com
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APGRES-2017 Working Committee Mr. Ankur Kulshreshtha Mr. Sohan Lal Swami Mr. Rajendra Prajapati Mr. Surya P. Meena Mr. Daljeet Singh Mr. Shailendra Goswami Mr. Himanshu Swarnkar Mr. Praful Patidar Mr. Prateek Dixit Mr. Rahul Gangwani Mr. Aditya P. Dixit Mr. Aditya Prakash Dixit Mr. Akhil Nema Mr. Ravi Prakash Maheshvari Ms. Sulbha Kothari Ms. Viveka Soni Mr. Pradeep K. Tank Mr. Praveen Rathore Mr. Kishan Singh Solanki
International Conference & Expo on
Advances in Power Generation from Renewable Energy Sources
(APGRES-2017) December 22-23, 2017