Power System Relaying, Third Edition

332 Pages·2008·4.9 MB·English

by  Stanley H. Horowitz

POWER SYSTEM
RELAYING
P ower System R elaying, Third Editio n. Stanley H . H or owitz and A r un G . Phadke
 2008 Resear ch Studies Pr ess L im ited. ISBN: 978-0-470-05712-4
POWER SYSTEM
RELAYING
Third Edition
Stanley H. Horowitz
ConsultingEngineer
Formerlywith AmericanElectricPowerCorporation
Columbus,Ohio,USA
Arun G. Phadke
UniversityDistinguishedProfessorEmeritus
VirginiaPolytechnic InstituteandState University
Blacksburg,Virginia,USA
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LibraryofCongressCataloging-in-PublicationData
Horowitz,StanleyH.,1925-
Powersystemsrelaying/StanleyH.Horowitz,ArunG.Phadke.–3rded.
p.cm.
Includesbibliographicalreferencesandindex.
ISBN978-0-470-05712-4(cloth)
1.Protectiverelays. 2. Electricpowersystems–Protection. I. Phadke,ArunG. II. Title.
TK2861.H672008
621.31(cid:1)7–dc22
2008002688
BritishLibraryCataloguinginPublicationData
AcataloguerecordforthisbookisavailablefromtheBritishLibrary
ISBN978-0-470-05712-4
Typesetin9/11TimesbyLaserwordsPrivateLimited,Chennai,India
PrintedandboundinGreatBritainbyAntonyRoweLtd,Chippenham,Wiltshire
Contents
Preface to the third edition xi
Preface to the second edition xiii
Preface to the first edition xv
1 Introduction to protective relaying 1
1.1 What is relaying? 1
1.2 Power system structural considerations 2
1.3 Power system bus configurations 4
1.4 The nature of relaying 7
1.5 Elements of a protection system 13
1.6 International practices 17
1.7 Summary 18
Problems 18
References 22
2 Relay operating principles 23
2.1 Introduction 23
2.2 Detection of faults 24
2.3 Relay designs 28
2.4 Electromechanical relays 29
2.5 Solid-state relays 37
2.6 Computer relays 41
2.7 Other relay design considerations 42
2.8 Control circuits, a beginning 44
2.9 Summary 45
Problems 45
References 47
3 Current and voltagetransformers 49
3.1 Introduction 49
3.2 Steady-state performance of current transformers 49
3.3 Transient performance of current transformers 56
3.4 Special connections of current transformers 59
3.5 Linear couplers and electronic current transformers 62
vi Contents
3.6 Voltage transformers 63
3.7 Coupling capacitor voltage transformers 64
3.8 Transient performance of CCVTs 67
3.9 Electronic voltagetransformers 70
3.10 Summary 70
Problems 71
References 72
4 Nonpilot overcurrent protection of transmission lines 75
4.1 Introduction 75
4.2 Fuses, sectionalizers,reclosers 77
4.3 Inverse, time-delay overcurrent relays 80
4.4 Instantaneous overcurrent relays 88
4.5 Directional overcurrent relays 90
4.6 Polarizing 92
4.7 Summary 96
Problems 96
References 99
5 Nonpilot distance protection of transmissionlines 101
5.1 Introduction 101
5.2 Stepped distance protection 101
5.3 R–X diagram 104
5.4 Three-phase distancerelays 108
5.5 Distance relay types 117
5.6 Relay operation with zero voltage 117
5.7 Polyphase relays 118
5.8 Relays for multi-terminal lines 119
5.9 Protection of parallel lines 121
5.10 Effect of transmission linecompensation devices 125
5.11 Loadability of relays 127
5.12 Summary 128
Problems 129
References 131
6 Pilot protection of transmission lines 133
6.1 Introduction 133
6.2 Communication channels 134
6.3 Tripping versus blocking 138
6.4 Directional comparison blocking 138
6.5 Directional comparison unblocking 142
6.6 Underreaching transfer trip 142
6.7 Permissive overreaching transfer trip 146
6.8 Permissive underreaching transfer trip 147
6.9 Phase comparison relaying 148
6.10 Current differential 151
6.11 Pilot wire relaying 151
6.12 Multi-terminal lines 153
Contents vii
6.13 Summary 155
Problems 156
References 157
7 Rotating machinery protection 159
7.1 Introduction 159
7.2 Stator faults 160
7.3 Rotor faults 174
7.4 Unbalanced currents 174
7.5 Overload 175
7.6 Overspeed 177
7.7 Abnormal voltages and frequencies 177
7.8 Loss of excitation 179
7.9 Loss of synchronism 180
7.10 Power plant auxiliary system 180
7.11 Winding connections 185
7.12 Startup and motoring 187
7.13 Inadvertent energization 189
7.14 Torsional vibration 189
7.15 Sequential tripping 190
7.16 Summary 190
Problems 191
References 193
8 Transformer protection 195
8.1 Introduction 195
8.2 Overcurrent protection 196
8.3 Percentage differential protection 198
8.4 Causes of false differential currents 201
8.5 Supervised differential relays 206
8.6 Three-phase transformer protection 208
8.7 Volts-per-hertz protection 212
8.8 Nonelectrical protection 213
8.9 Protection systems for transformers 214
8.10 Summary 220
Problems 221
References 223
9 Bus, reactor and capacitor protection 225
9.1 Introduction to bus protection 225
9.2 Overcurrent relays 226
9.3 Percentage differential relays 226
9.4 High-impedance voltage relays 227
9.5 Moderately high impedance relay 229
9.6 Linear couplers 229
9.7 Directional comparison 230
9.8 Partial differential protection 231
9.9 Introduction to shunt reactor protection 233
viii Contents
9.10 Dry-type reactors 233
9.11 Oil-immersed reactors 234
9.12 Introduction to shunt capacitor bank protection 235
9.13 Static var compensator protection 237
9.14 Static compensator 239
9.15 Summary 240
Problems 240
References 241
10 Power system phenomena and relaying considerations 243
10.1 Introduction 243
10.2 Power system stability 243
10.3 Steady-state stability 244
10.4 Transient stability 249
10.5 Voltage stability 253
10.6 Dynamics of systemfrequency 254
10.7 Series capacitors and reactors 258
10.8 Independent power producers 258
10.9 Islanding 259
10.10 Blackouts and restoration 259
10.11 Summary 262
Problems 262
References 262
11 Relaying for system performance 265
11.1 Introduction 265
11.2 System integrity protection schemes 265
11.3 Underfrequency load shedding 266
11.4 Undervoltage load shedding 268
11.5 Out-of-step relaying 268
11.6 Loss-of-field relaying 272
11.7 Adaptive relaying 273
11.8 Hidden failures 275
11.9 Distance relay polarizing 276
11.10 Summary 278
Problems 279
References 279
12 Switching schemes and procedures 281
12.1 Introduction 281
12.2 Relay testing 281
12.3 Computer programs for relay setting 283
12.4 Breaker failure relaying 284
12.5 Reclosing 286
12.6 Single-phase operation 287
12.7 Summary 287
References 288
Contents ix
13 Monitoring performance of power systems 289
13.1 Introduction 289
13.2 Oscillograph analysis 290
13.3 Synchronized sampling 297
13.4 Fault location 299
13.5 Alarms 303
13.6 COMTRADE and SYNCHROPHASOR standards 305
13.7 Summary 306
Problems 306
References 308
Appendix A: IEEE device numbers and functions 311
Appendix B: Symmetrical components 313
Appendix C: Power equipment parameters 317
Appendix D: Inverse time overcurrent relay characteristics 321
Index 325
Preface to the third edition
The second edition of our book, issued in 1995,continued to receive favorable responsefrom our
colleaguesand isbeingusedas atextbookby universitiesandinindustrycoursesworldwide.The
firsteditionpresentedthefundamentaltheoryofprotectiverelayingasappliedtoindividualsystem
components. This concept was continued throughout the second edition. In addition, the second
edition added material on generating plant auxiliary systems, distribution protection concepts and
theapplicationofelectronicinductiveandcapacitivedevicestoregulatesystemvoltage.Thesecond
editionalsopresentedadditionalmaterialcoveringmonitoringpowersystemperformanceandfault
analysis. The application of synchronized sampling and advanced timing technologies using the
Global PositioningSatellite (GPS) system was explained.
This third edition takes the problem of power system protection an additional step forward by
introducing power system phenomena which influence protective relays and for which protective
schemes, applications and settings must be considered and implemented. The consideration of
power system stability and the associated application of relays to mitigate its harmful effects are
presented in detail. New concepts such as undervoltage load shedding, adaptive relaying, hidden
failures and the Internet standard COMTRADE and its uses are presented. The history of notable
blackouts,particularlyasaffectedbyrelays,ispresentedtoenablestudentstoappreciatetheimpact
that protection systems have on the overall system reliability.
As mentioned previously, we are gratified with the response that the first and second editions
have received as both a textbook and a reference book. Recent changes in the electric power
industry have resulted in power system protection assuming a vital role in maintaining power
system reliability and security. It is the authors’ hope that the additions embodied in this third
edition will enable all electric power system engineers, designers and operators to better integrate
these concepts and to understand the complex interaction of relaying and system performance.
S. H. Horowitz
Columbus
A. G. Phadke
Blacksburg
Preface to the second edition
Thefirstedition,issuedin1992,hasbeenusedasatextbookbyuniversitiesandinindustrycourses
throughouttheworld.Althoughnotintendedasareferencebookforpracticingprotectionengineers,
ithasbeenwidelyusedasone.Asaresultofthisexperienceandofthedialogbetweentheauthors
andteachers,studentsandengineersusingthefirstedition,itwasdecidedtoissueasecondedition,
incorporatingmaterialwhichwouldbeofsignificantvalue.Thetheoryandfundamentalsofrelaying
constitutedthemajorpartofthefirsteditionanditremainssointhesecondedition.Inaddition,the
second edition includes concepts and practices that add another dimension to the study of power
system protection.
A chapter has been added covering monitoring power system performance and fault analysis.
Examples of oscillographic records introduce the student to the means by which disturbances
can be analyzed and corrective action and maintenance initiated. The application of synchronized
sampling for technologies such as the GPS satellite is explained. This chapter extends the basic
performanceofprotectiverelaystoincludetypicalpowersystemoperatingproblemsandanalysis.
A section covering power plant auxiliary systems has been added to the chapter on the protection
of rotating machinery. Distribution protection concepts have been expanded to bridge the gap
betweentheprotectionofdistributionandtransmissionsystems.Theemergingtechnologyofstatic
varcompensatorstoprovideinductiveandcapacitiveelementstoregulatesystemvoltagehasbeen
addedtothechapteronbusprotection.Thesubjectindexhasbeensignificantlyrevisedtofacilitate
reference from both theequipment and the operating perspective.
We are gratified with the response that the first edition has received as a text and reference
book.Theauthorsthanktheinstructorsandstudentswhosecommentsgeneratedmanyoftheideas
includedinthissecondedition.Wehopethatthebookwillcontinuetobebeneficialandofinterest
to students,teachers and power system engineers.
S. H. Horowitz
Columbus
A. G. Phadke
Blacksburg