//INTEGRAS/KCG/PAGINATION/WILEY/WPS/FINALS_14-12-04/0470855088_01_PREA01.3D – 3 – [1–48/48] 20.12.2004
7:23PM

Wind Power in Power
Systems
Edited by

Thomas Ackermann
Royal Institute of Technology
Stockholm, Sweden


//INTEGRAS/KCG/PAGINATION/WILEY/WPS/FINALS_14-12-04/0470855088_01_PREA01.3D – 3 – [1–48/48] 20.12.2004
7:23PM


//INTEGRAS/KCG/PAGINATION/WILEY/WPS/FINALS_14-12-04/0470855088_01_PREA01.3D – 1 – [1–48/48] 20.12.2004
7:23PM

Wind Power in Power
Systems

KTH

VETENSKAP
OCH KONST

ROYAL INSTITUTE
OF TECHNOLOGY
Electric Power
Systems

/>

//INTEGRAS/KCG/PAGINATION/WILEY/WPS/FINALS_14-12-04/0470855088_01_PREA01.3D – 2 – [1–48/48] 20.12.2004
7:23PM


//INTEGRAS/KCG/PAGINATION/WILEY/WPS/FINALS_14-12-04/0470855088_01_PREA01.3D – 3 – [1–48/48] 20.12.2004
7:23PM

Wind Power in Power
Systems
Edited by

Thomas Ackermann
Royal Institute of Technology
Stockholm, Sweden


//INTEGRAS/KCG/PAGINATION/WILEY/WPS/FINALS_14-12-04/0470855088_01_PREA01.3D – 4 – [1–48/48] 20.12.2004
7:23PM

Copyright Ó 2005

John Wiley & Sons, Ltd, The Atrium, Southern Gate, Chichester,
West Sussex PO19 8SQ, England
Telephone (þ44) 1243 779777

Email (for orders and customer service enquiries):
Visit our Home Page on www.wiley.com
All Rights Reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted

in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise,
except under the terms of the Copyright, Designs and Patents Act 1988 or under the terms of a licence issued
by the Copyright Licensing Agency Ltd, 90 Tottenham Court Road, London W1T 4LP, UK, without the
permission in writing of the Publisher. Requests to the Publisher should be addressed to the Permissions
Department, John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex PO19 8SQ,
England, or emailed to , or faxed to (þ44) 1243 770571.
This publication is designed to provide accurate and authoritative information in regard to the subject matter
covered. It is sold on the understanding that the Publisher is not engaged in rendering professional services.
If professional advice or other expert assistance is required, the services of a competent professional
should be sought.
Other Wiley Editorial Offices
John Wiley & Sons Inc., 111 River Street, Hoboken, NJ 07030, USA
Jossey-Bass, 989 Market Street, San Francisco, CA 94103-1741, USA
Wiley-VCH Verlag GmbH, Boschstr. 12, D-69469 Weinheim, Germany
John Wiley & Sons Australia Ltd, 33 Park Road, Milton, Queensland 4064, Australia
John Wiley & Sons (Asia) Pte Ltd, 2 Clementi Loop #02-01, Jin Xing Distripark, Singapore 129809
John Wiley & Sons Canada Ltd, 22 Worcester Road, Etobicoke, Ontario, Canada M9W 1L1
Library of Congress Cataloging in Publication Data
Wind power in power systems / edited by Thomas Ackermann.
p. cm
Includes bibliographical references and index.
ISBN 0-470-85508-8 (cloth : alk. paper)
1. Wind power plants. 2. Wind power. I. Ackermann, Thomas. II. Title.
TK1541.W558 2005
621.310 2136—dc22
2004018711
British Library Cataloguing in Publication Data
A catalogue record for this book is available from the British Library
ISBN 0-470-85508-8
Typeset in 10/12pt Times by Integra Software Services Pvt. Ltd, Pondicherry, India

Printed and bound in Great Britain by Antony Rowe Ltd, Chippenham, Wiltshire
This book is printed on acid-free paper responsibly manufactured from sustainable forestry in which at least
two trees are planted for each one used for paper production.


//INTEGRAS/KCG/PAGINATION/WILEY/WPS/FINALS_14-12-04/0470855088_01_PREA01.3D – 5 – [1–48/48] 20.12.2004
7:23PM

To Moana, Jonas and Nora


//INTEGRAS/KCG/PAGINATION/WILEY/WPS/FINALS_14-12-04/0470855088_01_PREA01.3D – 6 – [1–48/48] 20.12.2004
7:23PM


//INTEGRAS/KCG/PAGINATION/WILEY/WPS/FINALS_14-12-04/0470855088_01_PREA01.3D – 7 – [1–48/48] 20.12.2004
7:23PM

Contents

Contributors
Abbreviations
Notation
Units

xx
xxix
xxxvi
xlvi


1 Introduction
Thomas Ackermann

1

Part A Theoretical Background and Technical Regulations

5

2 Historical Development and Current Status of Wind Power
Thomas Ackermann

7

2.1 Introduction
2.2 Historical Background
2.2.1 Mechanical power generation
2.2.2 Electrical power generation
2.3 Current Status of Wind Power Worldwide
2.3.1 Overview of grid-connected wind power generation
2.3.2 Europe
2.3.3 North America
2.3.4 South and Central America
2.3.5 Asia and Pacific
2.3.6 Middle East and Africa
2.3.7 Overview of stand-alone generation
2.3.8 Wind power economics
2.3.9 Environmental issues
2.4 Status of Wind Turbine Technology
2.4.1 Design approaches

2.5 Conclusions
Acknowledgements
References

7
8
8
9
11
11
11
13
16
16
17
18
18
20
21
22
23
23
23


//INTEGRAS/KCG/PAGINATION/WILEY/WPS/FINALS_14-12-04/0470855088_01_PREA01.3D – 8 – [1–48/48] 20.12.2004
7:23PM

Contents


viii

3 Wind Power in Power Systems: An Introduction
Lennart So¨der and Thomas Ackermann
3.1
3.2
3.3
3.4
3.5
3.6

Introduction
Power System History
Current Status of Wind Power in Power Systems
Network Integration Issues for Wind Power
Basic Electrical Engineering
Characteristics of Wind Power Generation
3.6.1 The wind
3.6.2 The physics
3.6.3 Wind power production
3.7 Basic Integration Issues Related to Wind Power
3.7.1 Consumer requirements
3.7.2 Requirements from wind farm operators
3.7.3 The integration issues
3.8 Conclusions
Appendix: A Mechanical Equivalent to Power System Operation with
Wind Power
Introduction
Active power balance
Reactive power balance

References

4 Generators and Power Electronics for Wind Turbines
Anca D. Hansen
4.1 Introduction
4.2 State-of-the-art Technologies
4.2.1 Overview of wind turbine topologies
4.2.2 Overview of power control concepts
4.2.3 State-of-the-art generators
4.2.4 State-of-the-art power electronics
4.2.5 State-of-the-art market penetration
4.3 Generator Concepts
4.3.1 Asynchronous (induction) generator
4.3.2 The synchronous generator
4.3.3 Other types of generators
4.4 Power Electronic Concepts
4.4.1 Soft-starter
4.4.2 Capacitor bank
4.4.3 Rectifiers and inverters
4.4.4 Frequency converters
4.5 Power Electronic Solutions in Wind Farms
4.6 Conclusions
References
5 Power Quality Standards for Wind Turbines
John Olav Tande
5.1 Introduction
5.2 Power Quality Characteristics of Wind Turbines

25
25

25
26
28
29
32
32
33
34
40
40
41
41
46
47
47
48
49
50
53
53
53
53
55
55
59
62
65
66
69
70

72
72
72
73
74
75
77
77
79
79
80


//INTEGRAS/KCG/PAGINATION/WILEY/WPS/FINALS_14-12-04/0470855088_01_PREA01.3D – 9 – [1–48/48] 20.12.2004
7:23PM

Contents

5.2.1 Rated data
5.2.2 Maximum permitted power
5.2.3 Maximum measured power
5.2.4 Reactive power
5.2.5 Flicker coefficient
5.2.6 Maximum number of wind turbine switching operations
5.2.7 Flicker step factor
5.2.8 Voltage change factor
5.2.9 Harmonic currents
5.2.10 Summary power quality characteristics for various wind turbine types
5.3 Impact on Voltage Quality
5.3.1 General

5.3.2 Case study specifications
5.3.3 Slow voltage variations
5.3.4 Flicker
5.3.5 Voltage dips
5.3.6 Harmonic voltage
5.4 Discussion
5.5 Conclusions
References
6 Power Quality Measurements
Fritz Santjer
6.1 Introduction
6.2 Requirements for Power Quality Measurements
6.2.1 Guidelines
6.2.2 Specification
6.2.3 Future aspects
6.3 Power Quality Characteristics of Wind Turbines and Wind Farms
6.3.1 Power peaks
6.3.2 Reactive power
6.3.3 Harmonics
6.3.4 Flicker
6.3.5 Switching operations
6.4 Assessment Concerning the Grid Connection
6.5 Conclusions
References

ix

81
81
81

81
82
83
83
84
84
84
85
85
86
87
89
91
92
93
94
95
97
97
98
98
99
104
105
105
106
106
108
109
111

112
113

7 Technical Regulations for the Interconnection of Wind Farms to
the Power System
Julija Matevosyan, Thomas Ackermann and Sigrid M. Bolik

115

7.1 Introduction
7.2 Overview of Technical Regulations
7.2.1 Regulations for networks below 110 kV
7.2.2 Regulations for networks above 110 kV
7.2.3 Combined regulations
7.3 Comparison of Technical Interconnection Regulations
7.3.1 Active power control
7.3.2 Frequency control

115
115
117
119
120
121
122
123


//INTEGRAS/KCG/PAGINATION/WILEY/WPS/FINALS_14-12-04/0470855088_01_PREA01.3D – 10 – [1–48/48] 20.12.2004
7:23PM


Contents

x

7.3.3 Voltage control
7.3.4 Tap changers
7.3.5 Wind farm protection
7.3.6 Modelling information and verification
7.3.7 Communication and external control
7.3.8 Discussion of interconnection regulations
7.4 Technical Solutions for New Interconnection Rules
7.4.1 Absolute power constraint
7.4.2 Balance control
7.4.3 Power rate limitation control approach
7.4.4 Delta control
7.5 Interconnection Practice
7.6 Conclusions
References
8 Power System Requirements for Wind Power
Hannele Holttinen and Ritva Hirvonen
8.1 Introduction
8.2 Operation of the Power System
8.2.1 System reliability
8.2.2 Frequency control
8.2.3 Voltage management
8.3 Wind Power Production and the Power System
8.3.1 Production patterns of wind power
8.3.2 Variations of production and the smoothing effect
8.3.3 Predictability of wind power production

8.4 Effects of Wind Energy on the Power System
8.4.1 Short-term effects on reserves
8.4.2 Other short-term effects
8.4.3 Long-term effects on the adequacy of power capacity
8.4.4 Wind power in future power systems
8.5 Conclusions
References
9 The Value of Wind Power
Lennart So¨der
9.1 Introduction
9.2 The Value of a Power Plant
9.2.1 Operating cost value
9.2.2 Capacity credit
9.2.3 Control value
9.2.4 Loss reduction value
9.2.5 Grid investment value
9.3 The Value of Wind Power
9.3.1 The operating cost value of wind power
9.3.2 The capacity credit of wind power
9.3.3 The control value of wind power
9.3.4 The loss reduction value of wind power
9.3.5 The grid investment value of wind power

124
128
128
133
133
134
136

136
136
136
137
138
140
140
143
143
144
145
146
147
149
149
151
155
156
156
160
162
164
164
165
169
169
169
169
170
170

170
170
170
171
171
174
177
180


//INTEGRAS/KCG/PAGINATION/WILEY/WPS/FINALS_14-12-04/0470855088_01_PREA01.3D – 11 – [1–48/48] 20.12.2004
7:23PM

Contents

xi

9.4

180
180
181
182
188
189
194
195

The Market Value of Wind Power
9.4.1 The market operation cost value of wind power

9.4.2 The market capacity credit of wind power
9.4.3 The market control value of wind power
9.4.4 The market loss reduction value of wind power
9.4.5 The market grid investment value of wind power
9.5 Conclusions
References
Part B Power System Integration Experience

197

10 Wind Power in the Danish Power System
Peter Borre Eriksen and Carl Hilger

199

10.1
10.2

Introduction
Operational Issues
10.2.1 The Nordic market model for electricity trading
10.2.2 Different markets
10.2.3 Interaction between technical rules and the market
10.2.4 Example of how Eltra handles the balance task
10.2.5 Balancing via Nord Pool: first step
10.2.6 The accuracy of the forecasts
10.2.7 Network controller and instantaneous reserves
10.2.8 Balancing prices in the real-time market
10.2.9 Market prices fluctuating with high wind production
10.2.10 Other operational problems

10.3 System Analysis and Modelling Issues
10.3.1 Future development of wind power
10.3.2 Wind regime
10.3.3 Wind power forecast models
10.3.4 Grid connection
10.3.5 Modelling of power systems with large-scale wind
power production
10.3.6 Wind power and system analysis
10.3.7 Case study CO2 reductions according to the Kyoto
Protocol
10.4 Conclusions and Lessons Learned
References
11 Wind Power in the German Power System: Current Status and Future
Challenges of Maintaining Quality of Supply
Matthias Luther, Uwe Radtke and Wilhelm R. Winter
11.1
11.2
11.3
11.4
11.5
11.6
11.7

Introduction
Current Performance of Wind Energy in Germany
Wind Power Supply in the E.ON Netz Area
Electricity System Control Requirements
Network Planning and Connection Requirements
Wind Turbines and Dynamic Performance Requirements
Object of Investigation and Constraints


199
203
205
207
209
210
211
213
215
215
217
217
219
219
220
221
223
224
226
228
231
232

233
233
234
236
237
238

241
241


//INTEGRAS/KCG/PAGINATION/WILEY/WPS/FINALS_14-12-04/0470855088_01_PREA01.3D – 12 – [1–48/48] 20.12.2004
7:23PM

Contents

xii

11.8

Simulation Results
11.8.1 Voltage quality
11.8.2 Frequency stability
11.9 Additional Dynamic Requirements of Wind Turbines
11.10 Conclusions
References
12 Wind Power on Weak Grids in California and the US Midwest
H. M. Romanowitz
12.1
12.2

Introduction
The Early Weak Grid: Background
12.2.1 Tehachapi 66 kV transmission
12.2.2 VARs
12.2.3 FACTS devices
12.2.4 Development of wind energy on the Tehachapi 66 kV grid

12.2.5 Reliable generation
12.2.6 Capacity factor improvement: firming intermittent wind generation
12.3 Voltage Regulation: VAR Support on a Wind-dominated Grid
12.3.1 Voltage control of a self-excited induction machine
12.3.2 Voltage regulated VAR control
12.3.3 Typical wind farm PQ operating characteristics
12.3.4 Local voltage change from VAR support
12.3.5 Location of supplying VARs within a wind farm
12.3.6 Self-correcting fault condition: VAR starvation
12.3.7 Efficient-to-use idle wind turbine component capacity
for low-voltage VARs
12.3.8 Harmonics and harmonic resonance: location on grid
12.3.9 Islanding, self-correcting conditions and speed of response
for VAR controls
12.3.10 Self-correcting fault condition: VAR starvation
12.3.11 Higher-speed grid events: wind turbines that stay connected through
grid events
12.3.12 Use of advanced VAR support technologies on weak grids
12.3.13 Load flow studies on a weak grid and with induction machines
12.4 Private Tehachapi Transmission Line
12.5 Conclusions
References
13 Wind Power on the Swedish Island of Gotland
Christer Liljegren and Thomas Ackermann
13.1

13.2

Introduction
13.1.1 History

13.1.2 Description of the local power system
13.1.3 Power exchange with the mainland
13.1.4 Wind power in the South of Gotland
The Voltage Source Converter Based High-voltage Direct-current Solution
13.2.1 Choice of technology
13.2.2 Description
13.2.3 Controllability

244
244
248
252
254
255
257
257
259
259
260
260
261
262
263
264
264
264
265
267
268
269

270
271
274
275
276
278
279
280
281
282
283
283
283
285
286
286
287
287
287
288


//INTEGRAS/KCG/PAGINATION/WILEY/WPS/FINALS_14-12-04/0470855088_01_PREA01.3D – 13 – [1–48/48] 20.12.2004
7:23PM

Contents

13.2.4 Reactive power support and control
13.2.5 Voltage control
13.2.6 Protection philosophy

13.2.7 Losses
13.2.8 Practical experience with the installation
13.2.9 Tjæreborg Project
13.3 Grid Issues
13.3.1 Flicker
13.3.2 Transient phenomena
13.3.3 Stability issues with voltage control equipment
13.3.4 Validation
13.3.5 Power flow
13.3.6 Technical responsibility
13.3.7 Future work
13.4 Conclusions
Further Reading
References
14 Isolated Systems with Wind Power
Per Lundsager and E. Ian Baring-Gould
14.1 Introduction
14.2 Use of Wind Energy in Isolated Power Systems
14.2.1 System concepts and configurations
14.2.2 Basic considerations and constraints for wind–diesel power stations
14.3 Categorisation of Systems
14.4 Systems and Experience
14.4.1 Overview of systems
14.4.2 Hybrid power system experience
14.5 Wind Power Impact on Power Quality
14.5.1 Distribution network voltage levels
14.5.2 System stability and power quality
14.5.3 Power and voltage fluctuations
14.5.4 Power system operation
14.6 System Modelling Requirements

14.6.1 Requirements and applications
14.6.2 Some numerical models for isolated systems
14.7 Application Issues
14.7.1 Cost of energy and economics
14.7.2 Consumer demands in isolated communities
14.7.3 Standards, guidelines and project development approaches
14.8 Conclusions and Recommendations
References
15 Wind Farms in Weak Power Networks in India
Poul Sørensen
15.1 Introduction
15.2 Network Characteristics
15.2.1 Transmission capacity
15.2.2 Steady-state voltage and outages

xiii

288
288
289
290
290
291
291
292
292
293
294
295
296

296
296
297
297
299
299
300
300
305
310
311
312
312
315
316
316
317
317
320
321
322
322
324
325
325
327
328
331
331
334

334
335


//INTEGRAS/KCG/PAGINATION/WILEY/WPS/FINALS_14-12-04/0470855088_01_PREA01.3D – 14 – [1–48/48] 20.12.2004
7:23PM

Contents

xiv

15.2.3 Frequency
15.2.4 Harmonic and interharmonic distortions
15.2.5 Reactive power consumption
15.2.6 Voltage imbalance
15.3 Wind Turbine Characteristics
15.4 Wind Turbine Influence on Grids
15.4.1 Steady-state voltage
15.4.2 Reactive power consumption
15.4.3 Harmonic and interharmonic emission
15.5 Grid Influence on Wind Turbines
15.5.1 Power performance
15.5.2 Safety
15.5.3 Structural lifetime
15.5.4 Stress on electric components
15.5.5 Reactive power compensation
15.6 Conclusions
References

337

337
338
338
338
339
339
339
342
343
343
345
346
346
346
347
347

16 Practical Experience with Power Quality and Wind Power
A˚ke Larsson

349

16.1 Introduction
16.2 Voltage Variations
16.3 Flicker
16.3.1 Continuous operation
16.3.2 Switching operations
16.4 Harmonics
16.5 Transients
16.6 Frequency

16.7 Conclusions
References
17 Wind Power Forecast for the German and Danish Networks
Bernhard Ernst
17.1 Introduction
17.2 Current Development and Use of Wind Power Prediction Tools
17.3 Current Wind Power Prediction Tools
17.3.1 Prediktor
17.3.2 Wind Power Prediction Tool
17.3.3 Zephyr
17.3.4 Previento
17.3.5 eWind
17.3.6 SIPREO´LICO
17.3.7 Advanced Wind Power Prediction Tool
17.3.8 HONEYMOON project
17.4 Conclusions and Outlook
17.4.1 Conclusions
17.4.2 Outlook
References
Useful websites

349
349
352
352
354
358
360
361
363

363
365
365
366
367
367
368
370
370
370
371
372
376
377
377
380
380
381


//INTEGRAS/KCG/PAGINATION/WILEY/WPS/FINALS_14-12-04/0470855088_01_PREA01.3D – 15 – [1–48/48] 20.12.2004
7:23PM

Contents

18 Economic Aspects of Wind Power in Power Systems
Thomas Ackermann and Poul Erik Morthorst
18.1 Introduction
18.2 Costs for Network Connection and Network Upgrading
18.2.1 Shallow connection charges

18.2.2 Deep connection charges
18.2.3 Shallowish connection charges
18.2.4 Discussion of technical network limits
18.2.5 Summary of network interconnection and upgrade costs
18.3 System Operation Costs in a Deregulated Market
18.3.1 Primary control issues
18.3.2 Treatment of system operation costs
18.3.3 Secondary control issues
18.3.4 Electricity market aspects
18.4 Example: Nord Pool
18.4.1 The Nord Pool power exchange
18.4.2 Elspot pricing
18.4.3 Wind power and the power exchange
18.4.4 Wind power and the balancing market
18.5 Conclusions
References

xv

383
383
384
384
387
388
388
389
390
391
392

392
395
395
396
397
398
403
408
409

Part C Future Concepts

411

19 Wind Power and Voltage Control
J. G. Slootweg, S. W. H. de Haan, H. Polinder and W. L. Kling

413

19.1 Introduction
19.2 Voltage Control
19.2.1 The need for voltage control
19.2.2 Active and reactive power
19.2.3 Impact of wind power on voltage control
19.3 Voltage Control Capabilities of Wind Turbines
19.3.1 Current wind turbine types
19.3.2 Wind turbine voltage control capabilities
19.3.3 Factors affecting voltage control
19.4 Simulation Results
19.4.1 Test system

19.4.2 Steady-state analysis
19.4.3 Dynamic analysis
19.5 Voltage Control Capability and Converter Rating
19.6 Conclusions
References
20 Wind Power in Areas with Limited Transmission Capacity
Julija Matevosyan
20.1 Introduction
20.2 Transmission Limits
20.2.1 Thermal limit
20.2.2 Voltage stability limit

413
414
414
416
417
420
420
421
425
425
425
426
428
430
431
432
433
433

434
434
435


//INTEGRAS/KCG/PAGINATION/WILEY/WPS/FINALS_14-12-04/0470855088_01_PREA01.3D – 16 – [1–48/48] 20.12.2004
7:23PM

Contents

xvi

20.2.3 Power output of wind turbines
20.2.4 Transient stability
20.2.5 Summary
20.3 Transmission Capacity: Methods of Determination
20.3.1 Determination of cross-border transmission capacity
20.3.2 Determination of transmission capacity within the country
20.3.3 Summary
20.4 Measures to Increase Transmission Capacity
20.4.1 ‘Soft’ measures
20.4.2 Possible reinforcement measures: thermal limit
20.4.3 Possible reinforcement measures: voltage stability limit
20.4.4 Converting AC transmission lines to DC for higher transmission ratings
20.5 Impact of Wind Generation on Transmission Capacity
20.6 Alternatives to Grid Reinforcement for the Integration of Wind Power
20.6.1 Regulation using existing generation sources
20.6.2 Wind energy spillage
20.6.3 Summary
20.7 Conclusions

References
21 Benefits of Active Management of Distribution Systems
Goran Strbac, Predrag Djapic´, Thomas Bopp and Nick Jenkins
21.1 Background
21.2 Active Management
21.2.1 Voltage-rise effect
21.2.2 Active management control strategies
21.3 Quantification of the Benefits of Active Management
21.3.1 Introduction
21.3.2 Case studies
21.4 Conclusions
References
22 Transmission Systems for Offshore Wind Farms
Thomas Ackermann
22.1 Introduction
22.2 General Electrical Aspects
22.2.1 Offshore substations
22.2.2 Redundancy
22.3 Transmission System to Shore
22.3.1 High-voltage alternating-current transmission
22.3.2 Line-commutated converter based high-voltage direct-current transmission
22.3.3 Voltage source converter based high-voltage direct-current transmission
22.3.4 Comparison
22.4 System Solutions for Offshore Wind Farms
22.4.1 Use of low frequency
22.4.2 DC solutions based on wind turbines with AC generators
22.4.3 DC solutions based on wind turbines with DC generators
22.5 Offshore Grid Systems
22.6 Alternative Transmission Solutions
22.7 Conclusions


438
439
439
440
440
441
442
442
442
443
444
444
445
446
447
447
457
458
458
461
461
462
462
464
465
465
466
476
476

479
479
481
482
483
484
485
486
488
490
497
497
498
498
499
500
500


//INTEGRAS/KCG/PAGINATION/WILEY/WPS/FINALS_14-12-04/0470855088_01_PREA01.3D – 17 – [1–48/48] 20.12.2004
7:23PM

Contents

xvii

Acknowledgement
References
23 Hydrogen as a Means of Transporting and Balancing Wind Power Production
Robert Steinberger-Wilckens

23.1 Introduction
23.2 A Brief Introduction to Hydrogen
23.3 Technology and Efficiency
23.3.1 Hydrogen production
23.3.2 Hydrogen storage
23.3.3 Hydrogen transport
23.4 Reconversion to Electricity: Fuel Cells
23.5 Hydrogen and Wind Energy
23.6 Upgrading Surplus Wind Energy
23.6.1 Hydrogen products
23.7 A Blueprint for a Hydrogen Distribution System
23.7.1 Initial cost estimates
23.8 Conclusions
References
Part D

Dynamic Modelling of Wind Turbines for power System Studies

24 Introduction to the Modelling of Wind Turbines
Hans Knudsen and Jørgen Nyga˚rd Nielsen
24.1 Introduction
24.2 Basic Considerations regarding Modelling and Simulations
24.3 Overview of Aerodynamic Modelling
24.3.1 Basic description of the turbine rotor
24.3.2 Different representations of the turbine rotor
24.4 Basic Modelling Block Description of Wind Turbines
24.4.1 Aerodynamic system
24.4.2 Mechanical system
24.4.3 Generator drive concepts
24.4.4 Pitch servo

24.4.5 Main control system
24.4.6 Protection systems and relays
24.5 Per Unit Systems and Data for the Mechanical System
24.6 Different Types of Simulation and Requirements for Accuracy
24.6.1 Simulation work and required modelling accuracy
24.6.2 Different types of simulation
24.7 Conclusions
References
25 Reduced-order Modelling of Wind Turbines
J. G. Slootweg, H. Polinder and W. L. Kling
25.1
25.2
25.3
25.4

Introduction
Power System Dynamics Simulation
Current Wind Turbine Types
Modelling Assumptions

501
501
505
505
506
507
507
508
509
510

512
514
516
516
518
519
519
523
525
525
526
526
527
532
534
535
536
536
539
539
541
541
546
546
547
552
553
555
555
556

557
557


//INTEGRAS/KCG/PAGINATION/WILEY/WPS/FINALS_14-12-04/0470855088_01_PREA01.3D – 18 – [1–48/48] 20.12.2004
7:23PM

Contents

xviii

25.5 Model of a Constant-speed Wind Turbine
25.5.1 Model structure
25.5.2 Wind speed model
25.5.3 Rotor model
25.5.4 Shaft model
25.5.5 Generator model
25.6 Model of a Wind Turbine with a Doubly fed Induction Generator
25.6.1 Model structure
25.6.2 Rotor model
25.6.3 Generator model
25.6.4 Converter model
25.6.5 Protection system model
25.6.6 Rotor speed controller model
25.6.7 Pitch angle controller model
25.6.8 Terminal voltage controller model
25.7 Model of a Direct drive Wind Turbine
25.7.1 Generator model
25.7.2 Voltage controller model
25.8 Model Validation

25.8.1 Measured and simulated model response
25.8.2 Comparison of measurements and simulations
25.9 Conclusions
References
26 High-order Models of Doubly-fed Induction Generators
Eva Centeno Lo´pez and Jonas Persson
26.1
26.2
26.3
26.4

Introduction
Advantages of Using a Doubly-fed Induction Generator
The Components of a Doubly-fed Induction Generator
Machine Equations
26.4.1 The vector method
26.4.2 Notation of quantities
26.4.3 Voltage equations of the machine
26.4.4 Flux equations of the machine
26.4.5 Mechanical equations of the machine
26.4.6 Mechanical equations of the wind turbine
26.5 Voltage Source Converter
26.6 Sequencer
26.7 Simulation of the Doubly-fed Induction Generator
26.8 Reducing the Order of the Doubly-fed Induction Generator
26.9 Conclusions
References

27 Full-scale Verification of Dynamic Wind Turbine Models
Vladislav Akhmatov

27.1 Introduction
27.1.1 Background
27.1.2 Process of validation
27.2 Partial Validation
27.2.1 Induction generator model
27.2.2 Shaft system model

559
559
559
562
564
565
567
567
568
568
570
572
573
574
575
576
577
578
579
579
582
584
584

587
587
588
588
589
590
592
592
594
595
597
597
599
599
600
601
602
603
603
604
605
607
607
611


//INTEGRAS/KCG/PAGINATION/WILEY/WPS/FINALS_14-12-04/0470855088_01_PREA01.3D – 19 – [1–48/48] 20.12.2004
7:23PM

Contents


27.2.3 Aerodynamic rotor model
27.2.4 Summary of partial validation
27.3 Full-scale Validation
27.3.1 Experiment outline
27.3.2 Measured behaviour
27.3.3 Modelling case
27.3.4 Model validation
27.3.5 Discrepancies between model and measurements
27.4 Conclusions
References
28 Impacts of Wind Power on Power System Dynamics
J. G. Slootweg and W. L. Kling
28.1
28.2
28.3
28.4

xix

613
618
619
619
621
622
623
625
625
626

629

Introduction
Power System Dynamics
Actual Wind Turbine Types
Impact of Wind Power on Transient Stability
28.4.1 Dynamic behaviour of wind turbine types
28.4.2 Dynamic behaviour of wind farms
28.4.3 Simulation results
28.5 Impact of Wind Power on Small Signal Stability
28.5.1 Eigenvalue–frequency domain analysis
28.5.2 Analysis of the impact of wind power on small signal stability
28.5.3 Simulation results
28.5.4 Preliminary conclusions
28.6 Conclusions
References

629
630
631
632
632
636
638
645
645
646
647
648
650

651

29 Aggregated Modelling and Short-term Voltage Stability of Large Wind Farms
Vladislav Akhmatov

653

29.1 Introduction
29.1.1 Main outline
29.1.2 Area of application
29.1.3 Additional requirements
29.2 Large Wind Farm Model
29.2.1 Reactive power conditions
29.2.2 Faulting conditions
29.3 Fixed-speed Wind Turbines
29.3.1 Wind turbine parameters
29.3.2 Stabilisation through power ramp
29.4 Wind Turbines with Variable Rotor Resistance
29.5 Variable-speed Wind Turbines with Doubly-fed Induction Generators
29.5.1 Blocking and restart of converter
29.5.2 Response of a large wind farm
29.6 Variable-speed Wind Turbines with Permanent Magnet Generators
29.7 A Single Machine Equivalent
29.8 Conclusions
References
Index

653
654
655

655
656
657
658
658
661
661
663
665
667
668
670
672
673
673
677


//INTEGRAS/KCG/PAGINATION/WILEY/WPS/FINALS_14-12-04/0470855088_01_PREA01.3D – 20 – [1–48/48] 20.12.2004
7:23PM

Contributors

Thomas Ackermann has a Diplom Wirtschaftsingenieur (MSc in Mechanical Engineering
combined with an MBA) from the Technical University Berlin, Germany, an MSc in
Physics from Dunedin University, New Zealand, and a PhD from the Royal Institute of
Technology in Stockholm, Sweden. In addition to wind power, his main interests are
related to the concept of distributed power generation and the impact of market
regulations on the development of distributed generation in deregulated markets. He
has worked in the wind energy industry in Germany, Sweden, China, USA, New

Zealand, Australia and India. Currently, he is a researcher with the Royal Institute of
Technology (KTH) in Stockholm, Sweden, and involved in wind power education at
KTH and the University of Zagreb, Croatia, via the EU TEMPUS program. He is also a
partner in Energynautics.com, a consulting company in the area of sustainable energy
supply. Email:
Vladislav Akhmatov has an MSc (1999) and a PhD (2003) from the Technical University
of Denmark. From 1998 to 2003 he was with the Danish electric power company NESA.
During his work with NESA he developed dynamic wind turbine models and carried out
power system stability investigations, using mainly the simulation tool PSS/ETM. He
combined his PhD with work on several consulting projects involving Danish wind
turbine manufacturers on grid connection of wind farms in Denmark and abroad.
Specifically, he participated in a project regarding power system stability investigations
in connection with the grid connection of the Danish offshore wind farm at Rødsand/
Nysted (165 MW). He demonstrated that blade angle control can stabilise the operation
of the wind farm during grid disturbances. This solution is now applied in the Rødsand/
Nysted offshore wind farm. In 2003 he joined the Danish transmission system operator
in Western Denmark, Eltra. His primary work is dynamic modelling of wind turbines in
the simulation tool Digsilent Power-Factory, investigations of power system stability
and projects related to the Danish offshore wind farm at Horns Rev (160 MW). In 2002
he received the Angelo Award, which is a Danish award for exceptional contributions to

Wind Power in Power Systems Edited by T. Ackermann
Ó 2005 John Wiley & Sons, Ltd ISBN: 0-470-85508-8 (HB)


//INTEGRAS/KCG/PAGINATION/WILEY/WPS/FINALS_14-12-04/0470855088_01_PREA01.3D – 21 – [1–48/48] 20.12.2004
7:23PM

Contributors


xxi

the electric power industry, for ‘building bridges between the wind and the electric power
industries’. He has authored and co-authored a number of international publications on
dynamic wind turbine modelling and power system stability. Email:
E. Ian Baring-Gould graduated with a master’s degree in mechanical engineering from
the University of Massachusetts Renewable Energy Research Laboratory in the spring
of 1995, at which point he started working at the National Renewable Energy Laboratory (NREL) of the USA. Ian’s work at NREL has focused on two primary areas:
applications engineering for renewable energy technologies and international assistance
in renewable energy uses. His applications work concentrates on innovative uses of
renewable energies, primarily the modelling, testing and monitoring of small power
systems, end-use applications and large diesel plant retrofit concepts. International
technical assistance has focused on energy development for rural populations, including
the design, analysis and implementation of remote power systems. Ian continues to
manage and provide general technical expertise to international programs, focusing on
Latin America, Asia and Antarctica. Ian also sits on IEA and IEC technical boards, is
an editor for Wind Engineering and has authored or co-authored over 50 publications.
His graduate research centred on the Hybrid2 software hybrid, power system design,
code validation and the installation of the University’s 250 kW ESI-80 wind turbine.
Email:
Sigrid M. Bolik graduated in 2001 with a master’s degree in electrical engineering
(Diplom) from the Technical University Ilmenau in Germany. Currently, she works
for Vestas Wind Systems A/S in Denmark and also on her PhD in cooperation with
Aalborg University and Risø. Her research focuses on modelling induction machines for
wind turbine applications and developing wind turbine models for research in specific
abnormal operating conditions. Email:
Thomas Bopp is currently a research associate at the Electrical Energy and Power System
Research Group at UMIST, UK. His main research interests are power system protection
as well as power system economics and regulation. Email:
S. W. H. (Sjoerd) de Haan received his MSc degree in applied physics from the Delft

University of Technology, the Netherlands, in 1975. In 1995 he joined the Delft University of Technology as associate professor in power electronics. His research interest is
currently mainly directed towards power quality conditioning (i.e. the development of
power electronic systems for the conditioning of the power quality in the public electricity network). Email:
Predrag Djapic´ is currently a research associate at the Electrical Energy and Power
System Research Group at UMIST, UK. His main research interests are power system
planning and operation of distribution networks. Email:
Peter Borre Eriksen received an MSc degree in engineering from the Technical University of Denmark (DTU) in 1975. From 1980 until 1990 his work focused on the


//INTEGRAS/KCG/PAGINATION/WILEY/WPS/FINALS_14-12-04/0470855088_01_PREA01.3D – 22 – [1–48/48] 20.12.2004
7:23PM

xxii

Contributors

environmental consequences of power production. Between 1990 and 1998 he was
employed in the System Planning Department of the former Danish utility ELSAM.
In 1998, he joined Eltra, the independent transmission system operator of western
Denmark. In 2000, he became head of Eltra’s Development Department. Peter Borre
Eriksen is the author of numerous technical papers on system modelling. Email:

Bernhard Ernst is an electrical engineer and has a master’s degree (Diplom) in measurement and control from the University of Kassel, Germany. In 1994, still a student, he
joined ISET. In 2003, he completed at ISET a PhD on the prediction of wind power.
Bernhard Ernst has contributed to numerous publications on the subject of the integration of wind energy into energy supply. Email:
Anca D. Hansen received her PhD in modelling and control engineering from the
Technical University of Denmark (DTU) in 1997. In 1998 she joined the Wind Energy
Department of Risø National Laboratory. Her work and research interests focus on
dynamic modelling and the control of wind turbines as well as on the interaction of wind
farms with the grid. As working tools she uses the dynamic modelling and simulation

tools Matlab and Digsilent Power Factory. Her major contribution is the electromechanical modelling of active stall wind turbines and recently of a pitch-controlled variablespeed wind turbine with a doubly fed induction generator. She has also modelled PV
modules and batteries. Email:
Carl Hilger received a BSc in electrical engineering from the Engineering Academy of
Denmark and a general philosophy diploma as well as a bachelor of commerce degree.
In 1966 he joined Brown Boveri, Switzerland, as an electrical engineer and later the
Research Institute for Danish Electric Utilities (DEFU). In 1978 he became sectional
engineer in the Planning Department of Elsam (the Jutland-Funen Power Pool).
Between 1989 and 1997 he was executive secretary at Elsam and after that at Eltra,
the independent transmission system operator in the western part of Denmark. In 1998,
he was appointed head of the Operation Division at Eltra. Carl Hilger is a member of
Eurelectric Working Group SYSTINT and Nordel’s Operations Committee. Email:

Ritva Hirvonen has MSc and PhD degrees in electrical engineering from Helsinki
University of Technology and an MBA degree. She has broad experience regarding
power systems, transmission and generators. She has worked for the power company
Imatran Voima Oy and transmission system operator Fingrid as a power system
specialist and at VTT Technical Research Centre of Finland as research manager in
the energy systems area. Her current position is head of unit of Natural Gas and
Electricity Transmission for the Energy Market Authority (EMA) and she is actively
involved in research and teaching at the Power Systems Laboratory of Helsinki University of Technology. Email:
Hannele Holttinen has MSc (Tech) and LicSc (Tech) degrees from Helsinki University of
Technology. She has acquired broad experience regarding different aspects of wind


//INTEGRAS/KCG/PAGINATION/WILEY/WPS/FINALS_14-12-04/0470855088_01_PREA01.3D – 23 – [1–48/48] 20.12.2004
7:23PM

Contributors

xxiii


energy research since she started working for the VTT Technical Research Centre of
Finland in 1989. In 2000–2004 she worked mainly on her PhD on ‘Effects of Large Scale
Wind Power Production on the Nordic Electricity System’, with Nordic Energy
Research funding. Email:
Nick Jenkins is a professor of electrical energy and power systems at UMIST, UK. His
research interests are in the area of sustainable energy systems including renewable
energy and its integration in electricity distribution and transmission networks. Email:

W. L. (Wil) Kling received an MSc degree in electrical engineering from the Technical
University of Eindhoven in 1978. Currently, he is a part-time professor at the Electric
Power Systems Laboratory of Delft University of Technology. His expertise lies in the
area of planning and operating power systems. He is involved in scientific organisations,
such as IEEE. He is also the Dutch representative in the Cigre´ Study Committee C1
‘System Development and Economics’. Email:
Hans Knudsen received a MScEE from the Technical University of Denmark in 1991. In
1994 he received an industrial PhD, which was a joint project between the Technical
University of Denmark and the power companies Elkraft, SK Power and NESA. He
then worked in the in the Transmission Planning Department of the Danish transmission and distribution company NESA and focused on network planning, power system
stability and computer modelling, especially on modelling and simulation of HVDC
systems and wind turbines. In 2001, he joined the Danish Energy Authority, where he
works on the security of supply and power system planning. Email:
A˚ke Larsson received in 2000 a PhD from Chalmers University of Technology, Sweden.
His research focused on the power quality of wind turbines. He has broad experience
in wind power, power quality, grid design, regulatory requirements, measurements and
evaluation. He also participated in developing new Swedish recommendations for
the grid connection of wind turbines. Currently, he works for Swedpower. Email:

Christer Liljegren has a BScEE from Thorildsplan Technical Institute, Sweden. He
worked with nuclear power at ASEA, Vattenfall, with different control equipment,

mainly concerning hydropower, and at Cementa factory working with electrical industrial designing. In 1985, he joined Gotland Energiverk AB (GEAB) and in 1995 became
manager engineer of the electrical system on Gotland. He was project manager of the
Gotland HVDC-Light project. In 2001, Christer Liljegren started his own consulting
company, Cleps Electrical Power Solutions AB (CLEPS AB), specialising in technical
and legal aspects of distributed power generation, especially wind turbines and their
connection to the grid. He has been involved in developing guidelines and recommendations for connecting distributed generation in Sweden. Email:
Eva Centeno Lo´pez received an MSc degree in electrical engineering from Universidad
Pontificia Comillas in Madrid, Spain, in 2001, and a master’s degree at the Royal