Grid Integration and Dynamic Impact of Wind Energy

152 Pages·2013·3.763 MB·English

by  Vijay Vittal, Raja Ayyanar (auth.)

Power Electronics and Power Systems
Series Editors
M. A. Pai
Alex M. Stankovic
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Vijay Vittal Raja Ayyanar
•
Grid Integration
and Dynamic Impact
of Wind Energy
123
VijayVittal RajaAyyanar
School ofElectrical, Computer School ofElectrical, Computer
and EnergyEngineering and EnergyEngineering
ArizonaState University ArizonaState University
Tempe, AZ85287 Tempe, AZ85287
USA USA
ISBN 978-1-4419-9322-9 ISBN 978-1-4419-9323-6 (eBook)
DOI 10.1007/978-1-4419-9323-6
SpringerNewYorkHeidelbergDordrechtLondon
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(cid:2)SpringerScience+BusinessMediaNewYork2013
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Preface
Wind-based renewable energy generation has had a significant resurgence in the
pastdecade.Thisisprimarilyduetoadvancesintechnologydrivenbytheadvent
of variable speed wind turbine generators, which include doubly fed induction
generator-based wind turbines as well as full converter permanent magnet syn-
chronous machine based wind turbines. The versatility of these wind generators
canbelargelyattributedtopowerelectronicconvertersthatenablevariablespeed
operations while providing increasing grid support features. This resurgence has
resultedinasignificantnumberofwindfarmsbeinginterconnectedtotheelectric
grid all around the world. As a consequence, there has been renewed interest in
examiningandanalyzingtheimpactofincreasedpenetrationofwindresourceson
thesteady-stateanddynamicperformanceoftheinterconnectedgrid.Theneedto
understand and carefully analyze this impact has led to concerted efforts in the
development of models of different types of wind turbine generators, and the
incorporation of these models into analysis tools.
Modern wind turbine generators are complex devices, and examining their
impact on system behavior requires a careful study of wind turbine generators
together with their associated controls. In order to achieve this objective, there is
need to develop a deeper understanding of the critical components associated
with wind turbine generators, including the mechanical and dynamic character-
istics of wind turbines, the electrical and dynamic characteristics of generators,
and the characteristics of power electronic converters and their associated
controls.
The authors have been closely associated with the examination of the impact
of increased penetration of wind generation on system performance with their
colleagues and students. Other investigators have also made significant contri-
butions to this field. Our objective in developing this book is to present to the
reader an account of the salient aspects of the various wind turbine technologies,
details of the associated power electronic converters and their controls, and a
comprehensive discussion of the impact of wind turbine generators on system
dynamic performance of the electric grid. We hope that this book will provide an
understanding of the basics of wind turbine technology and their impact on
v
vi Preface
system performance. Finally, we wish to express our gratitude to the graduate
students, especially Youyuan Jiang, Siddharth Kulasekaran and Durga Gautam
for their help in providing many of the figures and simulation results, and to
Sunanda Vittal for her meticulous proof-reading.
Tempe, AZ, USA, February 2012 Vijay Vittal
Raja Ayyanar
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Overview of Wind Generation . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Wind Turbine Generator Technologies. . . . . . . . . . . . . . . . . . . 3
1.2.1 Type 1 Wind Turbine Generators . . . . . . . . . . . . . . . . . 4
1.2.2 Type 2 Wind Turbine Generators . . . . . . . . . . . . . . . . . 4
1.2.3 Type 3 Wind Turbine Generators . . . . . . . . . . . . . . . . . 5
1.2.4 Type 4 Wind Turbine Generators . . . . . . . . . . . . . . . . . 7
1.3 Detailed Representation and Modeling of Type 3 Wind
Turbine Generators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.3.1 DFIG as a Generator at Subsynchronous Speeds. . . . . . . 9
1.3.2 DFIG as a Generator at Supersynchronous Speeds . . . . . 10
1.3.3 Wind Power Model. . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.3.4 Mechanical Drive Train Model. . . . . . . . . . . . . . . . . . . 13
1.3.5 Modeling of Doubly Fed Induction Generator . . . . . . . . 14
1.4 Controls for Type 3 Wind Turbines. . . . . . . . . . . . . . . . . . . . . 17
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2 Power Electronic Concepts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.1 Components of a Power Electronic Converter System . . . . . . . . 19
2.1.1 Feedback Controller . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.1.2 Pulse-Width Modulator . . . . . . . . . . . . . . . . . . . . . . . . 21
2.1.3 Power Converter Circuit Topology . . . . . . . . . . . . . . . . 22
2.1.4 DC Link and Interface with External
Power Systems and Loads . . . . . . . . . . . . . . . . . . . . . . 23
2.2 Analysis of a Power Pole. . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
2.2.1 Switching Signal and Duty Ratio . . . . . . . . . . . . . . . . . 25
2.2.2 Pulse-Width Modulation of a Power Pole . . . . . . . . . . . 26
2.2.3 Pole Current and Analysis of DC Link Current . . . . . . . 29
2.2.4 Average Model of a Power Pole. . . . . . . . . . . . . . . . . . 32
2.3 Single Pole Converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
vii
viii Contents
2.4 Two-Pole Converter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
2.4.1 Average Model of a Two-Pole Converter. . . . . . . . . . . . 40
2.4.2 Unipolar PWM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
2.4.3 High Frequency Ripple with Unipolar PWM . . . . . . . . . 42
2.5 Three-Pole Converters for Three-Phase Applications. . . . . . . . . 46
2.6 Other Converter Topologies and PWM Methods. . . . . . . . . . . . 52
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
3 Power Converter Topologies for Grid Interface
of Wind Energy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
3.1 Variable Speed Operation and Grid Support Requirements. . . . . 55
3.2 Power Converters in Doubly Fed Induction Generator. . . . . . . . 56
3.2.1 Control Functions of Different Stages . . . . . . . . . . . . . . 58
3.2.2 Ratings of the Power Converters. . . . . . . . . . . . . . . . . . 58
3.2.3 Protection During Grid Faults. . . . . . . . . . . . . . . . . . . . 59
3.3 Power Converters for Type 4 Wind Generators. . . . . . . . . . . . . 60
3.3.1 Performance Under Grid Faults and Other Grid
Support Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
3.4 Other Emerging Power Converter Topologies. . . . . . . . . . . . . . 62
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
4 Control of Wind Generators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
4.1 Overview of Control of DFIG-Based Wind
Generator System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
4.2 Steady-State Analysis of DFIG with Per-Phase
Equivalent Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
4.2.1 Development of Per-Phase Equivalent Circuit . . . . . . . . 67
4.2.2 Speed-Torque Characteristics at Different
Rotor Voltages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
4.2.3 Steady-State Analysis at Various Wind
and Rotor Speeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
4.3 Dynamic Analysis of DFIG and Design of Controllers. . . . . . . . 81
4.3.1 Torque or Active Power and Reactive
Power References. . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
4.3.2 Grid Voltage Orientation . . . . . . . . . . . . . . . . . . . . . . . 84
4.3.3 References for Rotor d- and q-Axes Currents. . . . . . . . . 86
4.3.4 Controller Design for Rotor Current Loops . . . . . . . . . . 88
4.3.5 Control of the Grid Side Converter. . . . . . . . . . . . . . . . 90
4.3.6 Simulation Results . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
5 Dynamic Models for Wind Generators . . . . . . . . . . . . . . . . . . . . . 99
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
5.2 Modeling of Wind Turbine Generators
for Power Flow Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Contents ix
5.3 Modeling of Wind Turbine Generators for Transient
Stability Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
5.3.1 Aerodynamic Model . . . . . . . . . . . . . . . . . . . . . . . . . . 104
5.3.2 Mechanical Control and Shaft Dynamics. . . . . . . . . . . . 104
5.3.3 Electrical Generator Characteristics. . . . . . . . . . . . . . . . 105
5.3.4 Electrical Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
5.3.5 Generic Model for Type 3 Wind Turbine Generators . . . 107
5.4 Wind Farm Representation. . . . . . . . . . . . . . . . . . . . . . . . . . . 110
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
6 Impact of Increased Penetration of DFIG Wind Generators
on System Dynamic Performance. . . . . . . . . . . . . . . . . . . . . . . . . 115
6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
6.2 Impact on Rotor Angle Stability . . . . . . . . . . . . . . . . . . . . . . . 116
6.2.1 Impact on Small-Signal Rotor Angle Stability . . . . . . . . 116
6.2.2 Formulation of the Small-Signal Stability Problem . . . . . 117
6.2.3 Eigenvalue Sensitivity. . . . . . . . . . . . . . . . . . . . . . . . . 119
6.2.4 Example Study of Impact on Small-Signal
Rotor Angle Stability. . . . . . . . . . . . . . . . . . . . . . . . . . 121
6.2.5 Impact on Transient Rotor Angle Stability. . . . . . . . . . . 125
6.2.6 Example Study of Impact on Transient
Rotor Angle Stability. . . . . . . . . . . . . . . . . . . . . . . . . . 126
6.3 Impact on Voltage Response and Stability . . . . . . . . . . . . . . . . 130
6.3.1 Operating Modes of a DFIG Wind
Turbine Generator. . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
6.3.2 Voltage Ride Through. . . . . . . . . . . . . . . . . . . . . . . . . 130
6.3.3 Power Capability Curve of a DFIG Machine . . . . . . . . . 132
6.3.4 Impact of DFIG Wind Turbines on
Steady-State Voltage Stability . . . . . . . . . . . . . . . . . . . 133
6.4 Impact of DFIG Wind Turbine Generators
on System Frequency Response. . . . . . . . . . . . . . . . . . . . . . . . 135
6.4.1 Frequency Support from a DFIG Wind Turbine . . . . . . . 136
6.4.2 Pitch Compensation Adjustment. . . . . . . . . . . . . . . . . . 137
6.4.3 Maximum Power Order Adjustment . . . . . . . . . . . . . . . 138
6.4.4 Example of Effectiveness of Supplementary
Inertia Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
Chapter 1
Introduction
1.1 Overview of Wind Generation
Growth of wind power in the United States and around the world continues to
surpass even optimistic projections of the past years with a string of record
breaking years. In 2009 alone, 10 GW of new wind power capacity was added in
theUnitedStates,whichis20 %higherthantherecordsetin2008,andrepresents
39 % of all new capacity added in 2009 [1]. Figure. 1.1 [1], which superimposes
the actual installed wind generation with the deployment path laid out by [2] to
realizethevisionof20 %windby2030,showsdramaticallythattheactualgrowth
in the last 4 years and the projected growth in 2010–2012 far exceeded the
deployment plan.
Thoughaslowdownwasexpectedin2010,resurgenceisprojectedfor2011and
2012.TheNorthAmericanReliabilityCorporation(NERC)projectsthat210GW
of new wind capacity is planned for construction in the next 10 years [3], which
againexceedsthepacerequired—atotalof300GWby2030for20 %penetration.
Even at present, several states have high windpenetration; for example, Iowahas
19.7 % of its total generation derived from wind resources, and nine utilities are
estimatedtohavemorethan10 %windenergyontheirsystems.Aggregateddata
on interconnection queues from various ISOs and utilities also confirm the strong
interest and continued growth in wind. Figure 1.2 compares the different gener-
ation resources in 33 interconnection queues in 2009 with wind far exceeding the
other resources [1].
Several countries are taking steps to develop large-scale wind markets.
AccordingtonewsreleasedbytheGlobalWindEnergyCouncil(GWEC),thesum
ofthe world’s total windinstallationsincreasedby31 %toreach over 157.9 GW
by the end of 2009 [4]. The increase in capacity of over 100 % from 12.1 GW in
2008 to 25.1 GW (with new capacity additions of 13 GW) by the end of 2009
made China the number one market in terms of new wind power installations.
With the addition of nearly 10 GW of wind power in 2009, the United States
V.VittalandR.Ayyanar,GridIntegrationandDynamicImpactofWindEnergy, 1
PowerElectronicsandPowerSystems,DOI:10.1007/978-1-4419-9323-6_1,
(cid:2)SpringerScience+BusinessMediaNewYork2013
2 1 Introduction
Fig.1.1 Actual windinstallation versus deploymentpathrequired forrealizing 20%wind by
2030[1]
Fig.1.2 Capacityofvariousgenerationsourcesincludingwindandsolarin2010in33different
interconnectionqueues[1]
remained the leading nation in wind power in the year 2009 with 22.3 % of the
world’stotalinstalledwindcapacity.FollowinginrankwereChina,Germany,and
Spainwithinstalledcapacitiesof25.80,25.77,and19.14GW,respectively.Given
this scenario of significant wind penetration in the United States, also reflected in
other countries around the world, it is important to examine the impact of this
increasedwindpenetrationontheperformanceandreliabilityoftheelectricpower
system.