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 für 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. Jürgen Schmid
Dr. rer. nat. Oliver Führer
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:
ƒ improved gate control
ƒ optimised trash rack cleaner operation
ƒ higher turbine output (optimisation of runner –guide vane setting)
ƒ detailed monitoring and supervision
ƒ remote control and SCADA-interface (web cam, automated reports)
ƒ advanced analysis facilities
ƒ optimisation of multiple turbine installations
ƒ ...
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 Lüsen / 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 [m³/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 m³/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