INDIA belive Power From Sun + Battery(HESB) Green Power/Silent Power/Econmical Power Sabco Bijlee Milegi Hum Dekarke Rahenge
Presentation on Best Practice for Electrical Equipment Installation and Safety of Product(Earthing & Protection)
Solar PV Plant and India Target /Projection behind with Reality Safety and Efficiency Missing due to un Practical Decision by Some Developer forcing Component Supplier to Reduce Prices and also threating for un Practical Financial Long Credit Period Terms. Payment against Generation. Poor O&M We should not use water for cleaning of PV Panels practice dry cleaning of Friendly Chemicals. Add Hybrid Source of Generation Like Wind Machine or High Energy Storage Battaries.
Solar PV PUMP Programme CFA Pattern
• 30% capital subsidy to farmers through SNA • 40% through banks coupled with Loan
• State Nodal Agencies Implementi • NABARD and other banks ng Agencies • State Drinking Water Department
1,08,766 Solar Pumps Sanctioned
Rs.353.50 Crore was released various agencies. 63,436 pumps sanctioned to States (Irrigation)
30,000 was sanctioned to NABARD 15,330 nos. sanctioned to States (Drinking Water.
Electric Power Systems Lets us work till dark is away from Each Home Battery Power Generation
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Why and how it make sense to go with higher DC system voltage?
As entire solar Industry across the globe is facing heat in competitive bid recent years that is because of drastically fall of overall project cost of Solar PV plant and along with other factors i.e. Radiation, financing, credit worthyness of Offtaker etc. The drastically downfall of overall Solar PV system cost due to drastically change in Solar PV Module price (~0.80%-1.10%/Month since March 2015) and innovation ,optimization in BoS i.e. Solar Inverter, block size (smart block arrangement), optimized DC overloading, Structure design.Lets checkout- How Solar Industry shifted in Higher voltage installation on DC side Why did the industry move from 600 volt solar arrays to 1000 volt solar arrays? The answer is simple, to reduce system costs. The value of increased system voltages is realized in infrastructure savings, reduced installation costs, and end-to-end efficiency improvements. That is the same reason that the industry is now moving from 1000 volt systems to 1500 volt systems. Although 1000VDC-rated BOS equipment was generally more expensive than 600VDC equipment, those costs were more than offset by the cost reductions throughout the overall system. As the volume of the higher voltage rated components and wire increased, the installed costs were reduced even further. Again, the story is repeated with the move towards 1500VDC systems. The primary reason is the 31% to 37% decrease in DC current for the same power.
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• Lets talk about advantages first Lower DC Losses - Higher the system voltage lower the system current, for the same resistance ohmic losses will be lower Less Strings Reduced string cable length and Array cable length - Due to higher no. of module in series in case of 1500 V dc system compare to 1000 Vdc Reduction of String Combiner boxes Capex & Opex Saving Bigger Block Size - Concept of the bigger is better Understand the challenge O e ight ask h stop at 5 VDC? Wh as ’t it V? The short a s er is the solar pa el, s it hgear, fuse, a d ir uit reaker a ufa turers ere ’t read to ork ith a increase of 1000V, so the acceptable challenge was a 500V step above the 1000VDC rating. 1500V rated wire is not the problem. Switchgear, fuses, surge protectors, circuit breakers and other BOS components are still being introduced and certified. The reduction of current is the advantage, but the corresponding disadvantage is the conductor spacing (creep). Spacing must be greater for the higher voltages so the equipment gets correspondingly bigger and takes up more room. Internal arcing becomes a bigger concern so the design standards for these components become more complex and costly. 1500VDC fuses and 1500VDC disconnect switches, molded case switches, contactors, surge protective devices and sensors . Other manufacturers have joined in and the competition to supply the industry with the full range of 1500VDC rated components has both kept prices in check and increased the range of available product options. However, the list is still limited compared to those rated for 1000VDC. The good news is that at any given power capacity, with the increase in voltage, the current is reduced. Inverters are power conditioning units that esse tiall , push urre t at a fi ed oltage. The higher the urre t, the higher the heat and the higher the stress on current carrying components and switching devices. So a redu tio i urre t is, i ge eral, a good thi g fro the i erter’s perspe ti e
Efficiency and cost considerations for 1500Vdc PV Systems • Efficiency and cost considerations for 1500Vdc PV Systems • Higher output power levels can be obtained from essentially the same IGBT stacks if the current is reduced.The catch is that to work at the higher voltages, IGBTs have to be rated at the higher peak operating voltages. This means more expensive devices and higher switching losses. Some inverter manufacturers have had to accept lower efficiencies (usually .5% lower) compared to 1000VDC inverters. Sungrow has been able to maintain the same CEC energy conversion efficiencies in their line of 1500VDC inverters as they do in their line of central and string 1000VDC inverters (98.5%). • There are cost savings on the AC side of the inverter as well. With the increase in DC input voltage, the inverter can be designed for a higher AC output voltage. This reduces the AC current and allows for smaller gauge wire to be used for the wire runs from the inverters to the transformers. For example, a change from an output voltage of 480VAC to 600VAC reduces the current by 20%. For the same distance between the inverter and the point of connection to the transformer, this can mean a reduction of two wire sizes in most cases .
• Way forward- What does 1500 Vdc mean for Solar Industry in future • So where are the real savings? • If there is a premium for 1500VDC rated solar panels, and the 1500VDC rated BOS components have a premium, will that offset the savings in wire, labor, and other installation costs? If the inverter has a lower CEC weighted efficiency that results in a lower energy throughput, then the answer will be a resounding there will definitely be a reduction in the cost of the installed system. This is verified by the fact that virtually all utility scale project developers and EPCs are going with 1500VDC systems.
• A recent survey by IHS showed that the over-all savings estimates for 1500VDC system installations by experienced EPCs were in the range of 20% to 25% compared to 1000VDC systems. The variables include the cost of the wire (changes with the market price of copper), the local labor rates, union or non-union, system architectures, use of trackers, and the choice of inverters • 2. So where will the industry go from here? • It may move to even higher DC voltages, but the costs required to design and manufacture key components that can handle say, 2000VDC, may be too daunting. Most, if not all of the innovations and design changes have been incorporated based on their ability to reduce costs somewhere in the BOS components, installation, or O&M processes. Large volume orders and competition among 1500VDC component suppliers will continue to drive BOS costs down.
Fuse Selection Criteria of SMB (String Monitoring Box) in case of Solar System Design
• Fuse Selection Criteria of SMB (String Monitoring Box) in case of Solar System Design • In case of electrical system design anywhere as per standard practice we select fuse/breaker size with the help of the below formula: • Fuse/Breaker rating size = Current X 1.2 or 1.3 times • Suppose we selected 280Wp module, as per datasheet Isc is 8.68Amps so Selected Fuse = 8.68Amps X 1.25 = 10.85Amps so selected fuse say 12Amps • But in case of solar system design this formula many times fail to provide correct rating of fuses or fuses burnt frequently at site in the period of summer season. • Before starting we all have to know about this fact that in case of solar modules, irradiation is proportional to module current as well as temperature is proportional to module current (minutely) also, which means when irradiance & temperature will increase than module current will also increase from its rated current. • Reasons for burning of fuses (my own practical experience) : • As noted in datasheet All electrical parameter specified at STC 25degC cell temperature & 1000W/m2 irradiance, in summer season radiation will increase from 1000W/ m2 to 1100 to 1200W/m2 also temperature will increase. • Say at 1100W/m2 and 40deg ambient temperature Isc will become from 8.68Amps to 9.62 Amps
• Now when inner Box temp of SMB is 65degC (fuse holder) then as per derating of say fuse, fuse current carrying capacity will become from 12Amps to 9.5Amps at 65degC. • Particularly at this instance fuses will blown, also in summer season this will happen frequently at site. • So in case of fuses they will define selection of fuses as per below formula: • Fuse rating = Isc X 1.56 times • Fuse rating = Isc(8.68Amps) X 1.56 times(very safer side) = 13.54Amps so selected fuse say 15Amps • Conclusion: Before selecting fuse rating, solar designer has must to know about following informations: • Maximum Irradiation and ambient temperature of site in summer • Selection of SMB based on internal temperature rise calculation of each components.
Thanks
Mahesh Chandra Manav