Wind power in power systems

5.2.1 Rated data 815.2.10 Summary power quality characteristics for various wind turbine types 84 7 Technical Regulations for the Interconnection of Wind Farms to Julija Matevosyan, Thom

Wind Power in Power Systems

Edited by

Thomas Ackermann

Royal Institute of Technology

Stockholm, Sweden

Wind Power in Power Systems

Electric Power Systems

ROYAL INSTITUTE

OF TECHNOLOGY

KTH

VETENSKAP

Wind Power in Power Systems

Edited by

Thomas Ackermann

Royal Institute of Technology

Stockholm, Sweden

Copyright Ó 2005 John Wiley & Sons, Ltd, The Atrium, Southern Gate, Chichester,

West Sussex PO19 8SQ, England

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Library of Congress Cataloging in Publication Data

Wind power in power systems / edited by Thomas Ackermann.

Includes bibliographical references and index.

ISBN 0-470-85508-8 (cloth : alk paper)

TK1541.W558 2005

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.

To Moana, Jonas and Nora

Thomas Ackermann

3 Wind Power in Power Systems: An Introduction 25Lennart So¨der and Thomas Ackermann

Appendix: A Mechanical Equivalent to Power System Operation with

John Olav Tande

5.2.1 Rated data 81

5.2.10 Summary power quality characteristics for various wind turbine types 84

7 Technical Regulations for the Interconnection of Wind Farms to

Julija Matevosyan, Thomas Ackermann and Sigrid M Bolik

7.3.3 Voltage control 124

Hannele Holttinen and Ritva Hirvonen

9.4 The Market Value of Wind Power 180

Peter Borre Eriksen and Carl Hilger

10.3.7 Case study CO2reductions according to the Kyoto

11 Wind Power in the German Power System: Current Status and Future

Matthias Luther, Uwe Radtke and Wilhelm R Winter

12.2.6 Capacity factor improvement: firming intermittent wind generation 263

12.3.7 Efficient-to-use idle wind turbine component capacity

12.3.9 Islanding, self-correcting conditions and speed of response

12.3.11 Higher-speed grid events: wind turbines that stay connected through

Christer Liljegren and Thomas Ackermann

13.2 The Voltage Source Converter Based High-voltage Direct-current Solution 287

13.2.4 Reactive power support and control 288

Per Lundsager and E Ian Baring-Gould

14.2.2 Basic considerations and constraints for wind–diesel power stations 305

15.2.3 Frequency 337

18 Economic Aspects of Wind Power in Power Systems 383Thomas Ackermann and Poul Erik Morthorst

J G Slootweg, S W H de Haan, H Polinder and W L Kling

20.2.3 Power output of wind turbines 438

20.4.4 Converting AC transmission lines to DC for higher transmission ratings 444

Goran Strbac, Predrag Djapic´, Thomas Bopp and Nick Jenkins

22.3.2 Line-commutated converter based high-voltage direct-current transmission 48622.3.3 Voltage source converter based high-voltage direct-current transmission 488

Hans Knudsen and Jørgen Nyga˚rd Nielsen

J G Slootweg, H Polinder and W L Kling

25.5 Model of a Constant-speed Wind Turbine 559

Eva Centeno Lo´pez and Jonas Persson

27.2.3 Aerodynamic rotor model 613

J G Slootweg and W L Kling

Thomas Ackermann has a Diplom Wirtschaftsingenieur (MSc in Mechanical Engineeringcombined with an MBA) from the Technical University Berlin, Germany, an MSc inPhysics from Dunedin University, New Zealand, and a PhD from the Royal Institute ofTechnology in Stockholm, Sweden In addition to wind power, his main interests arerelated to the concept of distributed power generation and the impact of marketregulations on the development of distributed generation in deregulated markets Hehas worked in the wind energy industry in Germany, Sweden, China, USA, NewZealand, Australia and India Currently, he is a researcher with the Royal Institute ofTechnology (KTH) in Stockholm, Sweden, and involved in wind power education atKTH and the University of Zagreb, Croatia, via the EU TEMPUS program He is also apartner in Energynautics.com, a consulting company in the area of sustainable energysupply Email: Thomas.Ackermann@ieee.com

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 outpower system stability investigations, using mainly the simulation tool PSS/ETM Hecombined his PhD with work on several consulting projects involving Danish windturbine 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 inthe simulation tool Digsilent Power-Factory, investigations of power system stabilityand 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)

the electric power industry, for ‘building bridges between the wind and the electric powerindustries’ He has authored and co-authored a number of international publications ondynamic wind turbine modelling and power system stability Email: vla@eltra.dk.

E Ian Baring-Gould graduated with a master’s degree in mechanical engineering fromthe University of Massachusetts Renewable Energy Research Laboratory in the spring

of 1995, at which point he started working at the National Renewable Energy tory (NREL) of the USA Ian’s work at NREL has focused on two primary areas:applications engineering for renewable energy technologies and international assistance

Labora-in renewable energy uses His applications work concentrates on Labora-innovative uses ofrenewable energies, primarily the modelling, testing and monitoring of small powersystems, end-use applications and large diesel plant retrofit concepts Internationaltechnical assistance has focused on energy development for rural populations, includingthe design, analysis and implementation of remote power systems Ian continues tomanage and provide general technical expertise to international programs, focusing onLatin 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: ian_baring_gould@nrel.gov

Sigrid M Bolik graduated in 2001 with a master’s degree in electrical engineering(Diplom) from the Technical University Ilmenau in Germany Currently, she worksfor Vestas Wind Systems A/S in Denmark and also on her PhD in cooperation withAalborg University and Risø Her research focuses on modelling induction machines forwind turbine applications and developing wind turbine models for research in specificabnormal operating conditions Email: s.bolik@web.de

Thomas Bopp is currently a research associate at the Electrical Energy and Power SystemResearch Group at UMIST, UK His main research interests are power system protection

as well as power system economics and regulation Email: T.Bopp@umist.ac.uk

S W H (Sjoerd) de Haan received his MSc degree in applied physics from the DelftUniversity of Technology, the Netherlands, in 1975 In 1995 he joined the Delft Uni-versity of Technology as associate professor in power electronics His research interest iscurrently mainly directed towards power quality conditioning (i.e the development ofpower electronic systems for the conditioning of the power quality in the public elec-tricity network) Email: s.w.h.dehaan@ewi.tudelft.nl

Predrag Djapic´ is currently a research associate at the Electrical Energy and PowerSystem Research Group at UMIST, UK His main research interests are power systemplanning and operation of distribution networks Email: P.Djapic@umist.ac.uk

Peter Borre Eriksen received an MSc degree in engineering from the Technical versity of Denmark (DTU) in 1975 From 1980 until 1990 his work focused on the

Uni-environmental consequences of power production Between 1990 and 1998 he wasemployed in the System Planning Department of the former Danish utility ELSAM.

In 1998, he joined Eltra, the independent transmission system operator of westernDenmark In 2000, he became head of Eltra’s Development Department Peter BorreEriksen is the author of numerous technical papers on system modelling Email:pbe@eltra.dk

Bernhard Ernst is an electrical engineer and has a master’s degree (Diplom) in ment and control from the University of Kassel, Germany In 1994, still a student, hejoined 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 integra-tion of wind energy into energy supply Email: bernie.ernst@web.de

measure-Anca D Hansen received her PhD in modelling and control engineering from theTechnical University of Denmark (DTU) in 1997 In 1998 she joined the Wind EnergyDepartment of Risø National Laboratory Her work and research interests focus ondynamic modelling and the control of wind turbines as well as on the interaction of windfarms with the grid As working tools she uses the dynamic modelling and simulationtools Matlab and Digsilent Power Factory Her major contribution is the electromecha-nical modelling of active stall wind turbines and recently of a pitch-controlled variable-speed wind turbine with a doubly fed induction generator She has also modelled PVmodules and batteries Email: anca.daniela.hansen@risoe.dk

Carl Hilger received a BSc in electrical engineering from the Engineering Academy ofDenmark 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 theResearch Institute for Danish Electric Utilities (DEFU) In 1978 he became sectionalengineer 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 ofEurelectric Working Group SYSTINT and Nordel’s Operations Committee Email:carl@hilger.dk

Ritva Hirvonen has MSc and PhD degrees in electrical engineering from HelsinkiUniversity of Technology and an MBA degree She has broad experience regardingpower systems, transmission and generators She has worked for the power companyImatran Voima Oy and transmission system operator Fingrid as a power systemspecialist and at VTT Technical Research Centre of Finland as research manager inthe energy systems area Her current position is head of unit of Natural Gas andElectricity Transmission for the Energy Market Authority (EMA) and she is activelyinvolved in research and teaching at the Power Systems Laboratory of Helsinki Uni-versity of Technology Email: Ritva.Hirvonen@Energiamarkkinavirasto.fi

Hannele Holttinen has MSc (Tech) and LicSc (Tech) degrees from Helsinki University ofTechnology She has acquired broad experience regarding different aspects of wind

energy research since she started working for the VTT Technical Research Centre ofFinland in 1989 In 2000–2004 she worked mainly on her PhD on ‘Effects of Large ScaleWind Power Production on the Nordic Electricity System’, with Nordic EnergyResearch funding Email: Hannele.Holttinen@vtt.fi.

Nick Jenkins is a professor of electrical energy and power systems at UMIST, UK Hisresearch interests are in the area of sustainable energy systems including renewableenergy and its integration in electricity distribution and transmission networks Email:N.Jenkins@umist.ac.uk

W L (Wil) Kling received an MSc degree in electrical engineering from the TechnicalUniversity of Eindhoven in 1978 Currently, he is a part-time professor at the ElectricPower Systems Laboratory of Delft University of Technology His expertise lies in thearea 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: w.l.kling@ewi.tudelft.nl

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 TechnicalUniversity of Denmark and the power companies Elkraft, SK Power and NESA Hethen worked in the in the Transmission Planning Department of the Danish transmis-sion and distribution company NESA and focused on network planning, power systemstability and computer modelling, especially on modelling and simulation of HVDCsystems and wind turbines In 2001, he joined the Danish Energy Authority, where heworks on the security of supply and power system planning Email: HKN@ENS.dk

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 andevaluation He also participated in developing new Swedish recommendations forthe grid connection of wind turbines Currently, he works for Swedpower Email:ake.larsson@swedpower.com

Christer Liljegren has a BScEE from Thorildsplan Technical Institute, Sweden Heworked with nuclear power at ASEA, Vattenfall, with different control equipment,mainly concerning hydropower, and at Cementa factory working with electrical indus-trial designing In 1985, he joined Gotland Energiverk AB (GEAB) and in 1995 becamemanager engineer of the electrical system on Gotland He was project manager of theGotland HVDC-Light project In 2001, Christer Liljegren started his own consultingcompany, Cleps Electrical Power Solutions AB (CLEPS AB), specialising in technicaland legal aspects of distributed power generation, especially wind turbines and theirconnection to the grid He has been involved in developing guidelines and recommenda-tions for connecting distributed generation in Sweden Email: chl@cleps.se

Eva Centeno Lo´pez received an MSc degree in electrical engineering from UniversidadPontificia Comillas in Madrid, Spain, in 2001, and a master’s degree at the Royal

Institute of Technology, Stockholm, Sweden, in 2000 She then worked at Endesa,Madrid, Spain, at the Department of Electrical Market Currently, she works at theSwedish Energy Agency in Eskilstuna, Sweden Email: Eva.Centeno@stem.se.

Per Lundsager started working full-time with wind energy in 1975, including R&D,assessment, planning, implementation and evaluation of energy systems and concepts,for wind energy and other renewables Between 1984 and 1993 he was head of the winddiesel development programme at Risø National Laboratory As senior consultant hehas been advisor to the national wind energy centres in the USA, Canada, Finland,Denmark, Russia, Estonia, Poland, Brazil, India and Egypt, regarding projects, pro-grammes and strategies He has also been manager and/or participant in projects andstudies in the USA, Canada and Europe, including Greenland, Eastern Europe, Africaand Asia Email: per.lundsager@risoe.dk

Matthias Luther received a PhD in the field of electrical switchgear devices from theTechnical University of Braunschweig, Germany In 1993, he joined PreussenElektra

AG, Germany He was the project manager of various European network studies,mainly concerning system stability Between 1998 and 2000 he was in charge of networkdevelopment and customer services at the Engineering and Sales Department ofPreussenElektra Netz Presently, Matthias Luther is head of network planning at E.ONNetz GmbH, Bayreuth, Germany He is member of several national and internationalinstitutions and panels Email: Matthias.luther@eon-energie.com

Julija Matevosyan (Sveca) received a BSc degree in electrical engineering from RigaTechnical University, Latvia, in 1999 From 1999 to 2000 she worked as a planningengineer in the Latvian power company Latvenergo She received an MSc in electricalengineering from the Royal Institute of Technology, Stockholm, Sweden, in 2001 She iscurrently working at the Royal Institute of Technology towards a PhD on the large-scale integration of wind power in areas with limited transmission capability Email:julija@ekc.kth.se

Poul Erik Morthorst has a MEcon from the University of A˚rhus and is a senior researchspecialist in the Systems Analysis Department at Risø National Laboratory He joinedthis institute in 1978 His work has focused on general energy and environmentalplanning, development of long-term scenarios for energy, technology and environmen-tal systems, evaluation of policy instruments for regulating energy and environment andthe assessment of the economics of renewable energy technologies, especially windpower He has participated in a large number of projects within these fields and hasextensive experience in international collaboration Email: p.e.morthorst@risoe.dk

Jørgen Nyga˚rd Nielsen received a BScEE from the Engineering College of Sønderborg,Denmark, in 1984 From 1984 to 1988 he worked on developing digital control systemsand designing software for graphical reproduction systems Between 1988 and 1994

he was a lecturer at the College of Chemical Laboratory and Technician Education,Copenhagen In 1996, he received an MScEE from the Technical University ofDenmark and in 2000 an industrial PhD, a joint project between the Technical

University of Denmark, the Institute for Research and Development of the DanishElectric Utilities, Lyngby, Denmark, and Electricite´ de France, Clamart, France In

2000 he joined the Department of Transmission and Distribution Planning of theDanish transmission and distribution company NESA He works on general networkplanning, power system stability and the development of wind turbine simulationmodels Email: JON@NESA.dk

Jonas Persson received an MSc degree in electrical engineering from Chalmers sity of Technology, Go¨teborg, Sweden, in 1997 and a Tech Lic degree in electric powersystems from the Royal Institute of Technology, Stockholm, Sweden, in 2002 He joinedABB, Va¨stera˚s, Sweden, in 1995 where he worked on the development of the powersystem simulation software Simpow In 2004 he joined STRI, Ludvika, Sweden, where

Univer-he develops and teacUniver-hes Simpow Currently, Univer-he also works at tUniver-he Royal Institute ofTechnology in Stockholm, Sweden, towards a PhD on bandwidth-reduced linear models

of noncontinuous power system components Email: Jonas.Persson@stri.se

Henk Polinder received in 1992 an MSc degree in electrical engineering and in 1998 aPhD, both from the Delft University of Technology Currently, he is an associateprofessor at the Electrical Power Processing Laboratory at the same university, where

he gives courses on electrical machines and drives His main research interest is erator systems in renewable energy, such as wind energy and wave energy Email:h.polinder@ewi.tudelft.nl

gen-Uwe Radthe was born in 1948 He received the Doctor degree in Power Engineeringfrom the Technical University of Dresden in 1980 In 1990 he joined PreussenElektraand worked in the network planning department He was involved in internationalsystem studies as project manager and specialist of high voltage direct current transmis-sion systems From 2000 until 2003 he worked for E.ON Netz, responsible for systemintegration of renewable energy, especially wind power generation

Harold M Romanowitz is president and chief operating officer of Oak Creek EnergySystems Inc and a registered professional engineer He holds a BScEE from PurdueUniversity and an MBA from the University of California at Berkeley He has beeninvolved in the wind industry in California since 1985 and received the AWEA Techni-cal Achievement Award in 1991 for his turnaround work at Oak Creek He has beendirectly involved in efforts to improve the Tehachapi area grid over this time, includingthe achievement of a better understanding of the impacts of induction machines andimproved VAR support In 1992–93 he designed and operated a 2.88 MW 17 280 KWHbattery storage system directly integrated with wind turbines to preserve a firm capacitypower purchase agreement He was a manufacturer of engineered industrial drivesystems for many years, produced the first commercial regenerative thyristor drives inthe USA and WattMiser power recovery drives He has extensive experience withdynamic systems, including marine main propulsion (10 MW), large material handlingrobots, container and bulk-handling cranes, large pumps and coordinated process lines.Email: hal@rwitz.net

Fritz Santjer received an MSc (Diplom) in electrical engineering from the University ofSiegen, Germany, in 1989 In 1990 he joined the German Wind Energy Institute (DEWI)where he works on grid connection and the power quality of wind turbines and windfarms and on standalone systems In 2000 he became head of the Electrical SystemsGroup in DEWI He has performed commercial power quality and grid protectionmeasurements in many different countries in Europe, South America and Asia He is

an assessor for the MEASNET power quality procedure and is involved in national andinternational working groups regarding guidelines on power quality and the grid con-nection of wind turbines He lectures at national and international courses He wasinvolved in various European research projects concerning grid connection and powerquality of wind turbines, standalone systems and simulations of wind turbines andnetworks Email: f.santjer@dewi.de

J G (Han) Slootweg received an MSc degree in electrical engineering from DelftUniversity of Technology, the Netherlands, in 1998 The topic of his MSc thesis wasmodelling magnetic saturation in permanent-magnet linear machines In December

2003 he obtained a PhD from the Delft University of Technology His thesis was on

‘Wind Power; Modelling and Impact on Power System Dynamics’ He also holds anMSc degree in business administration from the Open University of the Netherlands.His MSc thesis focuses on how to ensure and monitor the long-term reliability ofelectricity networks from a regulator’s perspective Currently, he works with EssentNetwerk B.V in the Netherlands Email: han.slootweg@essent.nl

Lennart So¨der received MSc and PhD degrees in electrical engineering from the RoyalInstitute of Technology, Stockholm, Sweden, in 1982 and 1988, respectively He iscurrently a professor in electric power systems at the Royal Institute of Technology

He works with projects concerning deregulated electricity markets, distribution systems,protection systems, system reliability and integration of wind power Email: lennart.soder@ets.kth.se

Robert Steinberger-Wilckens received a physics degree in 1985 on the simulation ofpassive solar designs In 1993 he completed a PhD degree on the subject of couplinggeographically dispersed renewable electricity generation to electricity grids In 1985 hestarted an engineering consultancy PLANET (Planungsgruppe Energie und Technik) inOldenburg, Germany, of which he became a full-time senior manager in 1993 His workhas focused on complex system design and planning in energy and water supply, energysaving, hydrogen applications, building quality certificates and in wind, solar andbiomass projects In 1999–2000 he developed the hydrogen filling station EUHYFIS,funded within the CRAFT scheme of the EU In 2002 he joined the ForschungszentrumJu¨lich as project manager for fuel cells He is currently head of solid oxide fuel celldevelopment at the research centre Email: r.steinberger@planet-energie.de

Poul Sørensen has an MSc in electrical engineering (1987) He joined the Wind EnergyDepartment (VEA) of Risø National Laboratory in 1987 and now is a senior scientistthere Initially, he worked in the areas of wind turbine structural and aerodynamicmodelling Now, his research focuses on the interaction between wind energy and power

systems, with special interest in modelling and simulation He has been project manager

on a number of research projects in the field The modelling involves electrical aspects aswell as aeroelasticity and turbulence modelling Poul Sørensen has worked for severalyears on power quality issues, with a special focus on flicker emission from windturbines, and has participated in the work on the IEC 61400-21 standard for themeasurement and assessment of power quality characteristics for wind turbines Email:poul.e.soerensen@risoe.dk

Goran Strbac is a professor of electrical power engineering at UMIST, UK His researchinterests are in the area of power system analysis, planning and economics and inparticular in the technical and commercial integration of distributed generation in theoperation and development of power systems Email: G.Strbac@umist.ac.uk

John Olav Giæver Tande received his MSc in electrical engineering from the NorwegianInstitute of Science and Technology in 1988 After graduating he worked at the Norwe-gian Electric Power Research Institute (EFI) and then, from 1990 to 1997, he worked atRisø National Laboratory in Denmark After this he returned to SINTEF EnergyResearch (formerly EFI), where he is currently employed Throughout his career, hisresearch has been focused on the electrical engineering aspects of wind power He hasparticipated in several international studies, including convening an IEC working group

on preparing an international standard on the measurement and assessment of thepower quality characteristics of grid-connected wind turbines, and is the operating agentrepresentative of IEA Annex XXI: Dynamic Models of Wind Farms for Power SystemStudies (2002–2005) Email: john.o.tande@sintef.no

Wilhelm R Winter received an MSc and a PhD in power engineering from the TechnicalUniversity of Berlin in 1995 and 1998, respectively In 1995 he joined Siemens andworked in the department for protection development and in the system planningdepartment He was involved in large-system studies including stability calculations,HVDC and FACTS optimisations, modal analysis, transient phenomena, real-timesimulation and renewable energy systems He was responsible for the development ofthe NETOMAC Eigenvalue Analysis program In 2000 he started working at E.ONNetz, and is responsible for system dynamics and the integration of large-scale windpower Email: Wilhelm.Winter@eon-energie.com

A

ATC Available transfer capacity

AWPT Advanced Wind Power Prediction Tool

AWTS Atlantic Wind Test Site (Canada)

B

BJT Bipolar junction transistor

C

CANWea Canadian Wind Energy Association

CA-OWEA Concerted Action on Offshore Wind Energy in Europe

CEDRL CANMET Energy Diversification Research LaboratoryCENELEC Comite´ Europe´en de Normalisation Electrotechnique

CHP Combined heat and power (also known as co-generation)CIGRE´ Conseil International des Grands Re´seaux E´lectriques

Wind Power in Power Systems Edited by T Ackermann

Ó 2005 John Wiley & Sons, Ltd ISBN: 0-470-85508-8 (HB)

CP Connection point

CRES Centre for Renewable Energy Sources

D

DANIDA Danish International Development Agency

DEFU Research Institute for Danish Electric Utilities (also translated as

Danish Utilities Research Association)

DFIG Doubly fed induction generator

DMI Danish Meteorological Institute

DRE Distributed renewable energy

DRES Distributed renewable energy systems

DTU Technical University of Denmark

DWD Deutscher Wetterdienst (German Weather Service)

E

EDF Electricite´ de France

EEG Renewable Energy Sources Act (Germany)

EFI Electric Power Research Institute (Norway)

EMTP Electromagnetic transients program

ESB Electricity Supply Board (Republic of Ireland)

ESBNG Electricity Supply Board National Grid (Republic of Ireland)

ETR Engineering technical report

EU-15 European Union 15 Member States

EUHYFIS European Hydrogen Filling Station

GEB Gujarat Electricity Board

GEDA Gujarat Energy Development Agency

GIS Geographical information system

GTO Gate turn-off thyristor

H

HIRLAM High Resolution Limited Area Model

IEC International Electrotechnical Commission

IEEE Institute of Electrical and Electronic Engineers

IGBT Insulated gate bipolar transistor

IGCT Integrated gate commutated thyristor

IMM Department of Informatics and Mathematical Modelling (Technical

University of Denmark)IREQ Insitut de Recherche D’Hydro-Que´bec

IRR Internal rate of return

ISET Institu¨t fu¨r Solare Energieversorgnungstechnik

ISO Independent system operator (also commonly used for the International

Organisation for Standardisation, Geneva)IVS Instantaneous value simulation

LM Local Model (Lokal-Modell)

LOEE Loss of energy expectation

LOLE Loss of load expectation

LOLP Loss of load probability

LYSAN Linear System analysis (program module)

M

MARS Market Simulation Tool (Eltra)

MASS Mesoscale Atmospheric Simulation System

MCFC Molten carbonate fuel cell

MOS Model output statistics

MOSFET Metal oxide semiconductor field effect transistor

MSEK Million Swedish crowns (krona)

N

NERC North American Electricity Reliability Council

NETA New Electricity Trading Arrangement (UK)

NFFO The Non-Fossil Fuel Obligation (UK)

NOIS Nordic Operational Information System

NREA New and Renewable Energy Agency (Egypt)

NREL National Renewable Energy Laboratory (USA)

NTC Net transmission capacity

NTP Normal temperature and pressure

NWP Numerical weather prediction

O

OLTC On-load tap-changing (transformer)

OM&R Operation, maintenance and repair

OSIG OptiSlipTMinduction generator (OptiSlipTMis a registered trademark of

Vestas Wind Systems A/S)

P

PAFC Phosphoric acid fuel cell

PAS Publicly available specification

PDF Probability density function

PEFC Polymer electrolyte fuel cell

PG&E Pacific Gas and Electric (Company)

PSS/ETM Power System Simulator for Engineers [PSS/ETM is a registered

trademark of Shaw Power Technologies Inc (PTI)]

PURPA Public Utility Regulatory Policies Act (USA)

PWM Pulse-width modulated; pulse-width modulation

R

RERL-UMASS Renewable Energy Research Lab at UMass Amherst (USA)

RWTH Rheinisch-Westfa¨lische Technische Hochschule Aachen, Germany

(Institute of Technology of the Land North Rhine-Westphalia)

S

SCADA Supervisory control and data acquisition

SRG Switch reluctance generator

STATCOM Static VAR compensator

STATCON Static VAR converter

STP Standard temperature and pressure

SvK Svenka Kraftna¨t (Swedish transmission system operator)

T

TNEB Tamil Nadu Electricity Board

Type A Fixed-speed wind turbine, with asynchronous induction generator

directly connected to the grid, with or without reactive powercompensation (see also Section 4.2.3)

Type B Limited variable-speed wind turbine with variable generator rotor

resistance (see also Section 4.2.3)Type C Variable-speed wind turbine with doubly-fed asynchronous induction

generators and partial-load frequency converter on the rotor circuit(see also Section 4.2.3)

Type D Full variable-speed wind turbine, with asynchronous or synchronous

induction generator connected to the grid through a full-load frequencyconverter (see also Section 4.2.3)

U

UCTE Union pour la Coordination du Transport d’Electricite´ (Union for the

Coordination of Transmission of Electricity, formerly UCPTE)

WPMS Wind Power Management System

WPPT Wind Power Prediction Tool

WRIG Wound rotor induction generator

WRSG Wound rotor synchronous generator

Note: this book includes contributions from different authors who work in differentfields (i.e electrical and mechanical engineering and others) Within each of these fields,certain variables may be used for different concepts (e.g the variable R can denoteresistance and also radius, or it can represent the specific gas constant for air) It hasbeen the editor’s intention to reduce multiple definitions for one symbol However,sometimes there will be different denotions because some variables are commonly usedwithin different engineering disciplines This also means that similar concepts may not

be denoted with the same variable throughout the entire book

AR Area of wind turbine rotor; area through which wind flows

C

cP Power coefficient (of a wind turbine rotor)

cð kÞ Flicker coefficient for continuous operation as a function of network

impedance angle

ccð kÞ Flicker emission factor during normal operation

cð
k, VaÞ Flicker coefficient for continuous operation as a function of network

impedance angle and annual average wind speed

C Capacitor; capacitance; DC-link capacitor

CIC Installed capacity

Wind Power in Power Systems Edited by T Ackermann

Ó 2005 John Wiley & Sons, Ltd ISBN: 0-470-85508-8 (HB)

d Steady-state voltage change as a percentage of nominal voltage

D Shaft damping constant; load level

Dn Harmonic interference for each individual harmonic n

E

eR Real part of transformer impedance

eX Imaginary part of transformer impedance

EPlti Long-term flicker emission limit

EPsti Short-term flicker emission limit

E1 Voltage source of doubly fed induction generator (DFIG) rotor converter

or permanent magnet generator (PMG) converter

jE1j Magnitude of voltage source of DFIG rotor converter or PMG generator

E2 Voltage source of grid-side converter

E2
Active componant of voltage source of grid-side converter

E2 Reactive componant of voltage source of grid-side converter

Eload Average primary electrical load

Ewind Wind energy output

E(X) Expected value of quantity X

F

ffree–fixed Eigenfrequency of a free–fixed shaft system

ffree–free Eigenfrequency of a free–free shaft system

fps Pitch angle controller sample frequency

fss Rotor speed controller sample frequency

f(x) Gaussian probability function

fX(x) Probability mass function for variable X

F(x) Gaussian distribution function

h Wind turbine hub height; harmonic order

hsea Height above sea level

Hg Inertia constant of the induction generator

Hgen Generator rotor inertia constant

Hm Inertia constant of generator (mechanical)

Hwr Inertia constant of wind turbine

I

in Harmonic current of order n

in,k Harmonic current of order n from source k

i(t) Current as a function of time

irssr Stator current in the rotor reference frame

irr Rotor current in the rotor reference frame

iss Stator current in the stator reference frame

I1 Rotor current of DFIG or generator current of PMG

I1
Active rotor current of DFIG or active generator current of PMG

I1
, Ref Desired active rotor current of DFIG or desired active generator current

of PMG

I1  Reactive rotor current of DFIG or reactive generator current of PMG

I1 , Ref Desired reactive rotor current of DFIG or desired reactive generator

current of PMG

I2 Current of grid-side converter

I2
Active current of grid-side converter

I2
, Ref Desired active current of grid-side converter

I2 Reactive current of grid-side converter

I2, Ref Desired reactive current of grid-side converter

IMax Current-carrying capacity

IS Generator stator current

J

Jgen Generator rotor inertia

Jturb Wind turbine inertia

K

k Shaft stiffness; shape parameter of the Weibull distribution

kbase Base value of shaft stiffness, for use in a per unit system

k High-speed shaft stiffness in per unit