Understanding FACTS : concepts and technology of flexible AC transmission systems

442 Pages·2000·68.95 MB·English

by  Narain G Hingorani

Understanding FACTS
Concepts and Technology of
Flexible AC Transmission Systems
Narain G. Hingoranl
Hingorani Power Electronics
Los Altos Hills, CA
Laszlo Gyugyi
Siemens Power Transmission & Distribution
Orlando, FL
Mohamed E. El-Hawary, Consulting Editor
IEEE Power Engineering Society,Sponsor
+IEEE
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© 2000by the Institute ofElectrical and Electronics Engineers, Inc.
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Allrightsreserved.No part ofthisbookmay bereproduced in any form,
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Printed in the United States of America
10 9 8 7 6 5 4 3 2 1
ISBN0-7803-3455-8
IEEE OrderNo. peS'13
Library ofCongress Cataloging-in-PublicationData
Hingorani, Narain G.
UnderstandingFACTS: concepts and technology offlexible AC
transmission systems / Narain G. Hingorani, Laszlo Gyugyi.
p. em.
Includes bibliographical references and index.
ISBN 0-7803-3455-8
1. Flexible AC transmissionsystems. I. Gyugyi, Laszlo.
II. Title.
TK3148.H54 1999
621.319'13-dc21 99-29340
CIP
This book is dedicated to all the engineers
who have participated in the pioneering development
of FACTS technology.
CONTENT
PREFACE xiii
ACKNOWLEDGMENTS xvii
CHAPTER 1 FACTS Concept and General.System
Considerations 1
1.1 Transmission Interconnections 1
1.1.1 Why We Need Transmission Interconnections 1
1.1.2 Opportunities for FACfS 2
1.2 Flow of Power in an AC System 3
1.2.1 Power Flow in Parallel Paths 4
1.2.2 Power Flow in Meshed System 4
1.3 What Limits the Loading Capability? 7
1.4 Power Flow and Dynamic Stability Considerations
of a Transmission Interconnection 9
1.5 Relative Importance of Controllable Parameters 12
1.6 Basic Types of FACTS Controllers 13
1.6.1 Relative Importance of Different Types
of Controllers 14
1.7 BriefDescription and Definitions
of FACfS Controllers 16
1.7.1 Shunt Connected Controllers 18
1.7.2 Series Connected Controllers 20
1.7.3 Combined Shunt and Series Connected Controllers 23
1.7.4 Other Controllers 24
1.8 Checklist of Possible Benefits from FACfS
Technology 25
1.9 In Perspective: HVDC or FACfS 26
vii
viii Contents
CHAPTER 2 PowerSemiconductor Devices 37
2.1 Perspective on Power Devices 37
2.1.1 Types of High-Power Devices 40
2.2 Principal High-Power Device Characteristics
and Requirements 41
2.2.1 Voltage and Current Ratings 41
2.2.2 Lossesand Speed of Switching 42
2.2.3 ParameterTrade-Offof Devices 44
2.3 Power Device Material 45
2.4 Diode (Pn Junction) 46
2.5 Transistor 48
2.5.1 MOSFET 51
2.6 Thyristor (without Turn-Off Capability) 52
2.7 Gate Turn-OffThyristor (GTO) 54
2.7.1 Turn-On and Turn-OffProcess 56
2.8 MOS Turn-OffThyristor (MTO) 58
2.9 Emitter Turn-OffThyristor 60
2.10 Integrated Gate-Commutated Thyristor
(GCT and IGCT) 61
2.11 Insulated Gate Bipolar Transistor (IGBT) 63
2.12 MOS-Controlled Thyristor (MCT) 64
CHAPTER 3 Voltage-Sourced Converters 67
3.1 BasicConcept of Voltage-Sourced Converters 67
3.2 Single-Phase Full-Wave Bridge Converter Operation 69
3.3 SinglePhase-Leg Operation 72
3.4 Square-Wave Voltage Harmonics for a Single-Phase
Bridge 73
3.5 Three-Phase Full-Wave Bridge Converter 74
3.5.1 Converter Operation 74
3.5.2 Fundamental and Harmonics for a
Three-Phase Bridge Converter 77
3.6 Sequence of Valve Conduction Process in Each
Phase-Leg 80
3.7 Transformer Connections for 12-Pulse Operation 83
3.8 24-and 48-Pulse Operation 85
3.9 Three-Level Voltage-Sourced Converter 87
3.9.1 Operationof Three-Level Converter 87
3.9.2Fundamental and Harmonic Voltages for a
Three-Level Converter 88
3.9.3Three-Level Converter with Parallel Legs 91
3.10 Pulse-Width Modulation (PWM) Converter 91
3.11 Generalized Technique of Harmonic Elimination
and Voltage Control 95
3.12 Converter Rating-General Comments 97
Contents Ix
CHAPTER 4 Self- and Line-Commotated Current-Sourced
Converters 103
4.1 Basic Concept of Current-Sourced Converters 103
4.2 Three-Phase Full-Wave Diode Rectifier 106
4.3 Thyristor-Based Converter (With Gate Turn-On
but Without Gate Turn-Off) 110
4.3.1 Rectifier Operation 110
4.3.2 Inverter Operation 113
4.3.3 Valve Voltage 116
4.3.4 Commutation Failures 118
4.3.5 AC Current Harmonics 120
4.3.6 DC Voltage Harmonics 126
4.4 Current-Sourced Converter with Turn-Off Devices
(Current Stiff Converter) 129
4.5 Current-Sourced Versus Voltage-Sourced Converters 132
CHAPTER 5 Static Shunt Compensators: SVC
and STATCOM 135
5.1 Objectives of Shunt Compensation 135
5.1.1 Midpoint Voltage Regulation for Line Segmentation 135
5.1.2 End of Line Voltage Support to Prevent Voltage
Instability 138
5.1.3 Improvement ofTransient Stability 138
5.1.4 Power Oscillation Damping 142
5.1.5 Summary of Compensator Requirements 143
5.2 Methods of Controllable Var Generation 144
5.2.1 Variable ImpedanceType Static Var Generators 145
5.2.2 Switching ConverterType Var Generators 164
5.2.3 Hybrid Var Generators: Switching Converter
with TSC and TCR 177
5.2.4 Summaryof Static Var Generators 178
5.3 Static Var Compensators: SVC and STATCOM 179
5.3.1 The Regulation Slope 183
5.3.2 TransferFunction and Dynamic Performance 184
5.3.3 TransientStability Enhancement and Power
Oscillation Damping 188
5.3.4 Var Reserve (OperatingPoint) Control 193
5.3.5 Summaryof Compensator Control 195
5.4 Comparison Between STATCOM and SVC 197
5.4.1 V-I and V-Q Characteristics 197
5.4.2 Transient Stability 199.
5.4.3 Response Time 201
5.4.4 Capability to Exchange Real Power 201
5.4.5 Operation With Unbalanced AC System 202
5.4.6 Loss Versus Var Output Characteristic 204
5.4.7 Physical Sizeand Installation 204
5.4.8 Merits of Hybrid Compensator 205
5.5 Static Var Systems 205
Contents
CHAPTER 6 StaticSeries Compensators: GCSC, TSSC, TCSC,
and SSSC 209
6.1 Objectives of Series Compensation 209
6.1.1 Concept of Series Capacitive Compensation 210
6.1.2 Voltage Stability 211
6.1.3 Improvement ofTransient Stability 212
6.1.4 Power Oscillation Damping 213
6.1.5 Subsynchronous Oscillation Damping 214
6.1.6 Summary of Functional Requirements 215
6.1.7 Approaches to Controlled Series Compensation 216
6.2 Variable Impedance Type Series Compensators 216
6.2.1 GTO Thyristor-Controlled Series Capacitor (GCSC) 216
6.2.2 Thyristor-Switched Series Capacitor (TSSC) 223
6.2.3 Thyristor-Controlled Series Capacitor (TCSC) 225
6.2.4 Subsynchronous Characteristics 236
6.2.5 BasicOperating Control Schemes for GCSC, TSSC,
and TCSC 239
6.3 Switching Converter Type Series Compensators 243
6.3.1 The Static Synchronous Series Compensator (SSSC) 244
6.3.2 Transmitted Power Versus Transmission Angle
Characteristic 245
6.3.3 Control Range and VA Rating 248
6.3.4 Capability to Provide Real Power Compensation 250
6.3.5 Immunity to Subsynchronous Resonance 254
6.3.6 Internal Control 257
6.4 External (System) Control for Series Reactive Compensators
259
6.5 Summary of Characteristics and Features 261
CHAPTER 7 Static Voltage and Phase Angle Regulators: TCVR
and TCPAR 267
7.1 Objectives of Voltage and Phase Angle Regulators 267
7.1.1 Voltage and Phase Angle Regulation 269
7.1.2 Power Flow Control by Phase Angle Regulators 270
7.1.3 Real and Reactive Loop PowerFlow Control 272
7.1.4 Improvement ofTransient Stability with Phase
Angle Regulators 274
7.1.5 Power Oscillation Dampingwith Phase Angle
Regulators 276
7.1.6 Summary ofFunctional Requirements 277
7.2 Approaches to Thyristor-Controlled Voltage and Phase
Angle Regulators (TCVRs and TCPARs) 277
7.2.1 Continuously Controllable Thyristor Tap Changers 280
7.2.2 ThyristorTap Changerwith Discrete Level Control 286
7.2.3 ThyristorTap Changer Valve Rating Considerations 289
7.3 Switching Converter-Based Voltage and Phase Angle
Regulators 290
7.4 Hybrid Phase Angle Regulators 293
Contents
CHAPTER 8 Combined Compensators: Unified Power
Flow Controller (UPFC) and Interline Power
Flow Controller (IPFC) 297
8.1 Introduction 297
8.2 The Unified Power Flow Controller 299
8.2.1 Basic Operating Principles 300
8.2.2 ConventionalTransmission Control Capabilities 301
8.2.3 Independent Real and Reactive Power Flow Control 305
8.2.4 Comparison of UPFC to Series Compensators
and Phase Angle Regulators 308
8.2.5 Control Structure 315
8.2.6 Basic Control System for P and Q Control 319
8.2.7 Dynamic Performance 322
8.2.8 Hybrid Arrangements: UPFCwith a Phase
Shifting Transformer 329
8.3 The Interline Power Flow Controller (IPFC) 333
8.3.1 Basic Operating Principles and Characteristics 334
8.3.2 Control Structure 343
8.3.3 Computer Simulation 344
8.3.4 Practical and Application Considerations 346
8.4 Generalized and Multifunctional FACfS
Controllers 348
CHAPTER 9 Special Purpose Facts Controllers: NGH-SSR
Damping Scbeme and Thyristor-Controlled
Braking Resistor 353
9.1 Subsynchronous Resonance 353
9.2 NGH-SSR Damping Scheme 358
9.2.1 Basic Concept 358
9.2.2. Design and Operation Aspects 361
9.3 Thyristor-Controlled Braking Resistor (TCBR) 362
9.3.1 Basic Concept 362
9.3.2 Design and Operation Aspects 364
CHAPTER 10 Application Examples 373
10.1 WAPA's Kayenta Advanced Series Capacitor (ASC) 373
10.1.1 Introduction and Planning Aspects 373
10.1.2 Functional Specification 376
10.1.3 Design and Operational Aspects 377
10.1.4 Results of the Project 380
10.2 BPA's Slatt Thyristor-Controlled
Series Capacitor (TCSC) 382
10.2.1 Introduction and Planning Aspects 382
10.2.2 Functional Specifications 384
10.2.3 Design and Operational Aspects 387
10.2.4 Results of the Project 392
Contents
10.3 TVA's SullivanStatic Synchronous
Compensator (STATCOM) 394
10.3.1 Introduction and Planning Aspects 394
10.3.2STATCOM Design Summary 396
10.3.3Steady-State Performance 400
10.3.4Dynamic Performance 401
10.3.5Results of the Project 407
10.4 AEP's Inez Unified Power Flow Controller (UPFC) 407
10.4.1 Introduction and Planning Aspects 407
10.4.2Description of the UPFC 411
10.4.3OperatingPerformance 414
10.4.4 Results of the Project 423
INDEX 425
ABOUTTHE AUTHORS 431
Preface
Both authors of this book, Hingorani and Gyugyi, have been deeply involved in
pioneeringworkinthis new technologyofFlexibleACTransmissionSystem(FACfS).
Hingorani pioneered the concept and managed a large R&D effort from EPRI, and
GyugyiinventedandpioneeredseveralkeyFACfSControllerswhile leadingadevel
opmentteamat Westinghouse.Infact,bothhavebeeninvolvedinpioneeringadvances
in many other applications of power electronics.
FACfS is one aspect ofthe power electronics revolution that is taking place in
all areas of electric energy. A variety of powerful semiconductor devices not only
offer the advantage of high speed and reliability of switchingbut, more importantly,
the opportunity offered by a variety of innovative circuit concepts based on these
powerdevicesenhancethevalueofelectricenergy. This introductionispartlydevoted
to briefly conveyingthis perspectivebeforediscussingvariousspecifics of FlexibleAC
Transmission,thesubjectmatterofthisbook. Afterall,technologiesfromthetransistor
to microelectronics have revolutionized many aspects of our lives; there is no reason
whypowerdevicesshouldn'thaveasignificantimpactonourlivesaswell,atleastwhere
energyisconcerned.Thepowerelectronicsrevolutionishappening,andapplicationsof
power electronics will continue to expand.
In the generation area, the potential application of power electronics is largely
in renewable generation. Photo voltaic generation and fuel cells require conversion
of de to ac. Generation with variable speed isnecessary for the economic viability of
wind andsmall hydrogenerators.Variable-speedwindgeneratorsandsmallhydrogen
eratorsrequireconversionofvariablefrequency aeto powersystemfrequency. These
applications of power electronics in the renewable generation area generally require
converter sizes in the range of a few kilowatts to a few megawatts. Continuing
breakthroughs will determine if these technologies will make a significant impact on
electric power generation. In any case, they serve the vital needs of small, isolated
loads where taking utility wires would be more expensive. In thermal power plants,
considerable energy could be saved with the use of variable speed drives for pumps
and compressors.
In the coming decades, electrical energy storage is expected to be widely used
in power systems as capacitor, battery, and superconducting magnet technologies
xiii