Electrical Equipment for Small Hydropower Plants Generators with Permanent Magnet Excitation (PME)
Jochen Bard Head of Energy Conversion Institute for Solar Energy Supply Technologies (ISET) Kassel University, www.iset.de TNSHP: Small Hydropower Workshop
30th
Lausan June20
Institut f端r Solare Energieversorgungstechnik e.V.
Systems Technology for the Use of Renewable Energies and Efficient Energy Conversion Applications-oriented Research and Development Wind Energy Photovoltaics Use of Biomass Hydropower, Ocean Energy Technologies Energy Conversion and Storage Hybrid Systems Energy Economy Information and Training Executive Board: Prof. Dr.-Ing. J端rgen Schmid Dr. rer. nat. Oliver F端hrer Personnel: 75 Employees Budget: approxim. 8 Mio. Euro Information: www.iset.uni-kassel.de
Electrical Equipment for Small Hydropower Plants • turbine: electrical drives for guide vanes and runner control • generators: high efficiency induction machines, direct drive concepts • low loss & environmental friendly transformers • improved control: improved gate control optimised trash rack cleaner operation higher turbine output (optimisation of runner –guide vane setting) detailed monitoring and supervision remote control and SCADA-interface (web cam, automated reports) advanced analysis facilities optimisation of multiple turbine installations ...
examples of improvements in particular for modernisation
Medium to high head turbines small pelton
Source: Hitzinger
spiral case Francis
Project/Country: Type: Nominal output Speed: Specification:
EW L端sen / I SGT9D06T 1400 KVA 1000 rpm IEC 34, VDE 0530
Typical low head site: SHP plant Lewitzschleuse head: 3.6 m power: 270 kW discharge: 9 m³/s Turbine: Kaplan n = 190 rpm ∅ = 1600 mm
disadvantages of gearboxes losses of 1-1.5% per stage (up to 5% overall)
•
vibration and noise
•
investment cost and lifetime
•
maintenance requirements and cost
•
environmental risk from oil
efficienc
•
1 0,9 0,8 0,7 0,6 0,5 0,4 0,3 0,2 0,1 0 0
5
10 power [kW]
15
2
Alternative to gearboxes: reinforced belt (up to 400 kW)
Example of submersible turbines with direct coupled induction generator ITT Flyght
hydropower plant Reichenbach/Fils
Kaplan turbine: speed and torque vs discharge (simplified with constant design parameters) 800
80 turbine speed [rpm]
700
70
torque [kNm]
600
60
500
50
400
40
300
30
200
20
100
10
0
0 0
5
10
15
20
25
discharge [m続/s] at 5 m
90 kW
700 kW
torque [kNm][kNm] number of poles, torque
turbine speed [rpm]
equivalent number of poles
Performance improvement by replacing and old drive train 1 0,9
power train efficiency
0,8 0,7 0,6 PME generator
0,5
ASG+belt 0,4
old power train (ASG+ gear box)
0,3 0,2 0,1 0 0
10
20
30
40
50 Power [%]
60
70
80
90
100
Possible drive train arrangement for refurbishment using a direct coupled SE or PME synchronous generator
source: OKD
Design and operational aspetcs of grid connected PME generators + no excitation losses → very good part load efficiency + smaller pole pitches than separate excitation → lighter design + no brushes or slip rings - damping of oscillations between grid and rotor required - no regulation of the power factor - voltage proportional to speed → no regulation of the voltage run away speed + loss of load → very high open circuit voltages - no isolated operation possible
rotor
stator → only for integration into an existing strong and stable electrical network e.g. in Europe and North America
New compact turbine concepts using direct coupling Matrixturbine 200-700 kW per unit
ECOBulb Kaplan turbine 500 kW-5 MW 2 to 15 m
pictures: VATECH Hydro
ECOBulb: typical efficiencies achieved
generator
turbine
total
source: VATECH Hydro
ECOBulb generator first machine 330 kVA 214 rpm max. eff 96% pole face with magnets damper cage
1250 kVA, 150 rpm, max. eff 96,5% 4000 kVA 144 rpm max. eff 96,8% photos: VATECH Hydro
Straflo Matrix by VATECH
pictures: VATECH Hydro
StrafloMatrix pilot project Agonitz 700 kW at 8.5 m head 430 rpm, 1.12 m runner diameter unregulated turbine ring generator with PME target size > 1.5 MW
realised slow speed generators in µ-hydro demonstration projects refurbishment of a low head Francis turbine head 1m, discharge: 2.9 m³/s rated power 22 kVA rated speed 42 rpm
PME generator for a water wheel power 16 kW speed 22 rpm 24 poles efficiency 88% stator diameter 1,2m
rated torque 5000 Nm rated frequency 21 Hz power factor 1,0 weight 3,2 t Köhler, Karslruhe University , 1997
projects in Switzerland •engineering school Biehl •Swiss SHP programme 2003
source: Kassel University
EC-Project VASOCOMPACT: Development of a commercial concept for variable speed operation of unregulated submersible compact turbines
• new turbine design for runner and guide vane • special PME-generator directly coupled • special frequency converter • scaling from 50 bis 500 kW per unit • installation and test of a 50 kW pilot this summer (Tirva, Finnland)
Stator windings direct flow cooling
draft tube Rotor
Permanentmagnets
fix runner fix guide vanes
Generator with permanent magnet excitation (Elmotec, CH)
rated speed 600 rpm, 40 poles rated frequency 200 Hz design torque 840 Nm voltage 313 V, current 92 A
Application example for the VASOCOMPACT turbines
example design
3,18 m head 12,4 m続/s discharge 324 kW power/unit
1510 mm runner 265 rpm PME-Generator
Future prospects of PME generators Innowind 1.2 MW PMG 21 rpm 96 t
similar developments e.g. by Siemens: first PM motor in 1987 other applications: • CHP units based on ICEs • industrial drive applications
ABB medium Speed Permanent Magnet Generator integrated into a one-stage gearbox 120-240 rpm some MW new high speed PMG 3.6 MW on a 500mm frame >98% efficiency