Transmission and Distribution Electrical Engineering (eBook)

Front Cover 1
Transmission and Distribution Electrical Engineering 4
Copyright Page 5
Contents 6
About the authors 22
Contributors 24
Preface 28
Chapter 1 System Studies 30
1.1 Introduction 30
1.2 Load flow 30
1.2.1 Purpose 30
1.2.2 Sample study 31
1.3 System stability 37
1.3.1 Introduction 37
1.3.2 Analytical aspects 39
1.3.3 Steady state stability 43
1.3.4 Transient stability 46
1.3.5 Dynamic stability 57
1.3.6 Effect of induction motors 58
1.3.7 Data requirements and interpretation of transient stability studies 59
1.3.8 Case studies 64
1.4 Short circuit analysis 71
1.4.1 Purpose 71
1.4.2 Sample study 71
Chapter 2 Drawings and Diagrams 79
2.1 Introduction 79
2.2 Block diagrams 79
2.3 Schematic diagrams 80
2.3.1 Method of representation 80
2.3.2 Main circuits 84
2.3.3 Control, signalling and monitoring circuits 84
2.4 Manufacturers' drawings 84
2.4.1 Combined wiring/cabling diagrams 84
2.4.2 British practice 90
2.4.3 European practice 93
2.4.4 Other systems 96
2.5 Computer aided design (CAD) 97
2.6 Case study 98
2.7 Graphical symbols 98
Appendix A: Relay identification – numerical codes 100
Appendix B: Comparison between German, British, US/Canadian and international symbols 111
B1 General circuit elements 112
B2 Operating mechanisms 115
B3 Switchgear 118
Chapter 3 Substation Layouts 121
3.1 Introduction 121
3.2 Substation design considerations 121
3.2.1 Security of supply 121
3.2.2 Extendibility 122
3.2.3 Maintainability 122
3.2.4 Operational flexibility 123
3.2.5 Protection arrangements 123
3.2.6 Short circuit limitations 123
3.2.7 Land area 123
3.2.8 Cost 124
3.3 Alternative layouts 124
3.3.1 Single busbar 124
3.3.2 Transformer feeder 126
3.3.3 Mesh 130
3.3.4 Ring 132
3.3.5 Double busbar 133
3.3.6 1½ Circuit breaker 134
3.4 Space requirements 136
3.4.1 Introduction 136
3.4.2 Safety clearances 137
3.4.3 Phase–phase and phase–earth clearances 138
Chapter 4 Substation Auxiliary Power Supplies 144
4.1 Introduction 144
4.2 DC supplies 144
4.2.1 Battery and charger configurations 144
4.2.2 Battery charger components 147
4.2.3 Installation requirements 150
4.2.4 Typical enquiry data – DC switchboard 154
4.3 Batteries 155
4.3.1 Introduction 155
4.3.2 Battery capacity 155
4.3.3 Characteristics of batteries 156
4.3.4 Battery sizing calculations 159
4.3.5 Typical enquiry data 162
4.4 AC supplies 164
4.4.1 Power sources 164
4.4.2 LVAC switchboard fault level 166
4.4.3 Auxiliary transformer LV connections 166
4.4.4 Allowance for future extension 168
4.4.5 Typical enquiry data 168
4.4.6 Earthing transformer selection 169
4.4.7 Uninterruptible power supplies 173
Chapter 5 Current and Voltage Transformers 178
5.1 Introduction 178
5.2 Current transformers 178
5.2.1 Introduction 178
5.2.2 Protection CT classifications 178
5.2.3 Metering CTs 182
5.2.4 Design and construction considerations 183
5.2.5 Terminal markings 185
5.2.6 Specifications 186
5.3 Voltage transformers 186
5.3.1 Introduction 186
5.3.2 Electromagnetic VTs 186
5.3.3 Capacitor VTs 187
5.3.4 Specifications 188
5.4 Future trends 188
Chapter 6 Insulators 192
6.1 Introduction 192
6.2 Insulator materials 192
6.2.1 Polymeric and resin materials 192
6.2.2 Glass and porcelain 193
6.3 Insulator types 193
6.3.1 Post insulators 193
6.3.2 Cap and pin insulators 197
6.3.3 Long rod 197
6.4 Pollution control 198
6.4.1 Environment/creepage distances 198
6.4.2 Remedial measures 201
6.4.3 Calculation of specific creepage path 202
6.5 Insulator specification 203
6.5.1 Standards 203
6.5.2 Design characteristics 203
6.6 Tests 209
6.6.1 Sample and routine tests 209
6.6.2 Technical particulars 209
Chapter 7 Substation Building Services 210
7.1 Introduction 210
7.2 Lighting 210
7.2.1 Terminology 210
7.2.2 Internal lighting 215
7.2.3 External lighting 216
7.2.4 Control 226
7.3 Distribution characterization 228
7.4 Heating, ventilation and air-conditioning 229
7.4.1 Air circulation 229
7.4.2 Air-conditioning 231
7.4.3 Heating 236
7.5 Fire detection and suppression 236
7.5.1 Introduction 236
7.5.2 Fire extinguishers 237
7.5.3 Access, first aid and safety 237
7.5.4 Fire detection 238
7.5.5 Fire suppression 241
7.5.6 Cables, control panels and power supplies 242
Chapter 8 Earthing and Bonding 244
8.1 Introduction 244
8.2 Design criteria 244
8.2.1 Touch and step voltages 244
8.2.2 Touch and step voltage limits 245
8.3 Substation earthing calculations 248
8.3.1 Environmental conditions 248
8.3.2 Earthing materials 251
8.3.3 Earth resistance and earth potential rise 254
8.3.4 Hazard voltage tolerable limits 256
8.4 Computer simulation 258
References 261
Chapter 9 Insulation Co-ordination 262
9.1 Introduction 262
9.2 System voltages 262
9.2.1 Power frequency voltage 262
9.2.2 Overvoltages 263
9.3 Clearances 274
9.3.1 Air 274
9.3.2 SF[sub(6)] 277
9.4 Procedures for co-ordination 277
9.4.1 The IEC standard approach 277
9.4.2 Statistical approach 278
9.4.3 Non-statistical approach 280
9.5 Surge protection 280
9.5.1 Rod or spark gaps 280
9.5.2 Surge arresters 282
References 297
Chapter 10 Relay Protection 298
10.1 Introduction 298
10.2 System configurations 299
10.2.1 Faults 299
10.2.2 Unearthed systems 299
10.2.3 Impedance earthed systems 299
10.2.4 Solidly earthed systems 300
10.2.5 Network arrangements 300
10.3 Power system protection principles 303
10.3.1 Discrimination by time 303
10.3.2 Discrimination by current magnitude 304
10.3.3 Discrimination by time and fault direction 304
10.3.4 Unit protection 304
10.3.5 Signalling channel assistance 305
10.4 Current relays 306
10.4.1 Introduction 306
10.4.2 Inverse definite minimum time lag (IDMTL) relays 306
10.4.3 Alternative characteristic curves 309
10.4.4 Plotting relay curves on log/log graph paper 309
10.4.5 Current relay application examples 310
10.5 Differential protection schemes 321
10.5.1 Biased differential protection 321
10.5.2 High impedance protection 324
10.5.3 Transformer protection application examples 325
10.5.4 Pilot wire unit protection 329
10.5.5 Busbar protection 332
10.6 Distance relays 335
10.6.1 Introduction 335
10.6.2 Basic principles 336
10.6.3 Relay characteristics 336
10.6.4 Zones of protection 342
10.6.5 Switched relays 343
10.6.6 Typical overhead transmission line protection schemes 344
10.7 Auxiliary relays 348
10.7.1 Tripping and auxiliary 348
10.7.2 AC auxiliary relays 352
10.7.3 Timers 352
10.7.4 Undervoltage 354
10.7.5 Underfrequency 354
10.8 Computer assisted grading exercise 355
10.8.1 Basic input data 355
10.8.2 Network fault levels 357
10.8.3 CT ratios and protection devices 357
10.8.4 Relay settings 357
10.9 Practical distribution network case study 358
10.9.1. Introduction 358
10.9.2. Main substation protection 359
10.9.3. Traction system protection 360
10.9.4. 21 kV distribution system and protection philosophy 361
10.9.5. 21 kV pilot wire unit protection 363
10.9.6. 21 kV system back-up protection 364
10.9.7. Use of earth fault indicators 366
10.9.8. Summary 366
10.10 Recent advances in control, protection and monitoring 366
10.10.1 Background 366
10.10.2 Developments 367
References 369
Chapter 11 Fuses and Miniature Circuit Breakers 370
11.1 Introduction 370
11.2 Fuses 370
11.2.1 Types and standards 370
11.2.2 Definitions and terminology 374
11.2.3 HRC fuses 374
11.2.4 High voltage fuses 377
11.2.5 Cartridge fuse construction 384
11.3 Fuse operation 386
11.3.1 High speed operation 386
11.3.2 Discrimination 386
11.3.3 Cable protection 389
11.3.4 Motor protection 391
11.3.5 Semiconductor protection 392
11.4 Miniature circuit breakers 392
11.4.1 Operation 392
11.4.2 Standards 396
11.4.3 Application 397
References 402
Chapter 12 Cables 403
12.1 Introduction 403
12.2 Codes and standards 403
12.3 Types of cables and materials 406
12.3.1 General design criteria 406
12.3.2 Cable construction 407
12.3.3 Submarine cables 415
12.3.4 Joints and terminations 417
12.4 Cable sizing 418
12.4.1 Introduction 418
12.4.2 Cables laid in air 419
12.4.3 Cables laid direct in ground 419
12.4.4 Cables laid in ducts 424
12.4.5 Earthing and bonding 425
12.4.6 Short circuit ratings 427
12.4.7 Calculation examples 429
12.5 Calculation of losses in cables 439
12.5.1 Dielectric losses 439
12.5.2 Screen or sheath losses 440
12.6 Fire properties of cables 440
12.6.1 Introduction 440
12.6.2 Toxic and corrosive gases 440
12.6.3 Smoke emission 441
12.6.4 Oxygen index and temperature index 442
12.6.5 Flame retardance/flammability 442
12.6.6 Fire resistance 443
12.6.7 Mechanical properties 444
12.7 Control and communication cables 444
12.7.1 Low voltage and multicore control cables 444
12.7.2 Telephone cables 445
12.7.3 Fibre optic cables 446
12.8 Cable management systems 452
12.8.1 Standard cable laying arrangements 452
12.8.2 Computer aided cable installation systems 455
12.8.3 Interface definition 458
References 464
Chapter 13 Switchgear 465
13.1 Introduction 465
13.2 Terminology and standards 465
13.3 Switching 467
13.3.1 Basic principles 467
13.3.2 Special switching cases 479
13.3.3 Switches and disconnectors 482
13.3.4 Contactors 485
13.4 Arc quenching media 489
13.4.1 Introduction 489
13.4.2 Sulphur hexafluoride (SF[sub(6)]) 492
13.4.3 Vacuum 493
13.4.4 Oil 497
13.4.5 Air 499
13.5 Operating mechanisms 501
13.5.1 Closing and opening 501
13.5.2 Interlocking 506
13.5.3 Integral earthing 506
13.6 Equipment specifications 509
13.6.1 12 kV metal-clad indoor switchboard example 509
13.6.2 Open terminal 145 kV switchgear examples 515
13.6.3 Distribution system switchgear example 520
13.6.4 Distribution ring main unit 521
References 527
Chapter 14 Power Transformers 528
14.1 Introduction 528
14.2 Standards and principles 528
14.2.1 Basic transformer action 528
14.2.2 Transformer equivalent circuit 530
14.2.3 Voltage and current distribution 532
14.2.4 Transformer impedance representation 533
14.2.5 Tap changers 535
14.2.6 Useful standards 544
14.3 Voltage, impedance and power rating 546
14.3.1 General 546
14.3.2 Voltage drop 546
14.3.3 Impedance 547
14.3.4 Voltage ratio and tappings – general 548
14.3.5 Voltage ratio with off-circuit tappings 548
14.3.6 Voltage ratio and on-load tappings 549
14.3.7 Basic insulation levels (BIL) 549
14.3.8 Vector groups and neutral earthing 549
14.3.9 Calculation example to determine impedance and tap range 552
14.4 Thermal design 561
14.4.1 General 561
14.4.2 Temperature rise 561
14.4.3 Loss of life expectancy with temperature 562
14.4.4 Ambient temperature 563
14.4.5 Solar heating 564
14.4.6 Transformer cooling classifications 564
14.4.7 Selection of cooling classification 567
14.4.8 Change of cooling classification in the field 568
14.4.9 Capitalization of losses 569
14.5 Constructional aspects 570
14.5.1 Cores 570
14.5.2 Windings 571
14.5.3 Tanks and enclosures 573
14.5.4 Cooling plant 575
14.5.5 Low fire risk types 576
14.5.6 Neutral earthing transformers 578
14.5.7 Reactors 578
14.6 Accessories 581
14.6.1 General 581
14.6.2 Buchholz relay 581
14.6.3 Sudden pressure relay and gas analyser relay 582
14.6.4 Pressure relief devices 582
14.6.5 Temperature monitoring 582
14.6.6 Breathers 583
14.6.7 Miscellaneous 583
14.6.8 Transformer ordering details 585
References 593
Chapter 15 Substation and Overhead Line Foundations 594
15.1 Introduction 594
15.2 Soil investigations 594
15.3 Foundation types 595
15.4 Foundation design 604
15.5 Site works 605
15.5.1 Setting out 605
15.5.2 Excavation 606
15.5.3 Piling 606
15.5.4 Earthworks 608
15.5.5 Concrete 609
15.5.6 Steelwork fixings 612
Chapter 16 Overhead Line Routing 614
16.1 Introduction 614
16.2 Routing objectives 614
16.3 Preliminary routing 616
16.3.1 Survey equipment requirements 616
16.3.2 Aerial survey 616
16.3.3 Ground survey 616
16.3.4 Ground soil conditions 616
16.3.5 Wayleave, access and terrain 617
16.3.6 Optimization 618
16.4 Detailed line survey and profile 620
16.4.1 Accuracy requirements 620
16.4.2 Profile requirements 621
16.4.3 Computer aided techniques 622
Chapter 17 Structures, Towers and Poles 624
17.1 Introduction 624
17.2 Environmental conditions 626
17.2.1 Typical parameters 626
17.2.2 Effect on tower or support design 626
17.2.3 Conductor loads 632
17.3 Structure design 640
17.3.1 Lattice steel tower design considerations 640
17.3.2 Tower testing 652
17.4 Pole and tower types 653
17.4.1 Pole structures 653
17.4.2 Tower structures 654
References 658
Chapter 18 Overhead Line Conductor and Technical Specifications 659
18.1 Introduction 659
18.2 Environmental conditions 659
18.3 Conductor selection 660
18.3.1 General 660
18.3.2 Types of conductor 661
18.3.3 Aerial bundled conductor and BLX 662
18.3.4 Conductor breaking strengths 666
18.3.5 Bi-metal connectors 668
18.3.6 Corrosion 668
18.4 Calculated electrical ratings 670
18.4.1 Heat balance equation 670
18.4.2 Power carrying capacity 671
18.4.3 Corona discharge 674
18.4.4 Overhead line calculation example 678
18.5 Design spans, clearances and loadings 680
18.5.1 Design spans 680
18.5.2 Conductor and earth wire spacing and clearances 693
18.5.3 Broken wire conditions 703
18.5.4 Conductor tests/inspections 703
18.6 Overhead line fittings 704
18.6.1 Fittings related to aerodynamic phenomena 704
18.6.2 Suspension clamps 706
18.6.3 Sag adjusters 707
18.6.4 Miscellaneous fittings 707
18.7 Overhead line impedance 707
18.7.1 Inductive reactance 707
18.7.2 Capacitive reactance 709
18.7.3 Resistance 709
18.8 Substation busbar selection – case study 710
18.8.1 Introduction 710
18.8.2 Conductor diameter/current carrying capacity 710
18.8.3 Conductor selection on weight basis 710
18.8.4 Conductor short circuit current capability 713
18.8.5 Conductor support arrangements 716
References 721
Chapter 19 Testing and Commissioning 722
19.1 Introduction 722
19.2 Quality assurance 723
19.2.1 Introduction 723
19.2.2 Inspection release notice 725
19.2.3 Partial acceptance testing 725
19.2.4 System acceptance testing 725
19.2.5 Documentation and record systems 725
19.3 Works inspections and testing 727
19.3.1 Objectives 727
19.3.2 Specifications and responsibilities 728
19.3.3 Type tests 728
19.3.4 Routine production tests 729
19.4 Site inspection and testing 729
19.4.1 Pre-commissioning and testing 729
19.4.2 Maintenance inspection 730
19.4.3 On-line inspection and testing 730
19.5 Testing and commissioning methods 734
19.5.1 Switchgear 734
19.5.2 Transformers 742
19.5.3 Cables 747
19.5.4 Protection 753
Appendix A: Commissioning test procedure requirements 767
Appendix B: Drawings, diagrams and manuals 768
Chapter 20 Electromagnetic Compatibility 770
20.1 Introduction 770
20.2 Standards 771
20.3 Compliance 772
20.4 Testing 773
20.4.1 Introduction 773
20.4.2 Magnetic field radiated emission measurements 773
20.4.3 Electric field radiated emission measurements 775
20.4.4 Conducted emission measurements 777
20.4.5 Immunity testing 778
20.5 Screening 779
20.5.1 Introduction 779
20.5.2 The use of screen wire 779
20.5.3 The use of screen boxes and Faraday enclosures 779
20.5.4 The use of screen floors in rooms 781
20.6 Typical useful formulae 784
20.6.1 Decibel reference levels 784
20.6.2 Field strength calculations 784
20.6.3 Mutual inductance between two long parallel pairs of wires 785
20.6.4 Attenuation factors 785
20.7 Case studies 786
20.7.1 Screening power cables 786
20.7.2 Measurement of field strengths 790
References 792
Chapter 21 Supervisory Control and Data Acquisition 793
21.1 Introduction 793
21.2 Programmable logic controllers 793
21.2.1 Functions 793
21.2.2 PLC selection 794
21.2.3 Application example 799
21.3 Power line carrier communication links 805
21.3.1 Introduction 805
21.3.2 Power line carrier communication principles 806
21.4 Supervisory control and data acquisition 809
21.4.1 Introduction 809
21.4.2 Typical characteristics 812
21.4.3 Design issues 814
21.4.4 Example (Channel Tunnel) 815
21.5 Software management 817
21.5.1 Software – a special case 818
21.5.2 Software life cycle 819
21.5.3 Software implementation practice 822
21.5.4 Software project management 825
References 827
Chapter 22 Project Management 828
22.1 Introduction 828
22.2 Project evaluation 828
22.2.1 Introduction 828
22.2.2 Financial assessment 829
22.2.3 Economic assessment 836
22.3 Financing 840
22.3.1 Responsibilities for funding 840
22.3.2 Cash flow 840
22.3.3 Sources of finance 841
22.3.4 Export credit agencies 841
22.3.5 Funding risk reduction 842
22.3.6 Use of private finance 843
22.4 Project phases 845
22.4.1 The project life cycle 845
22.4.2 Cash flow 846
22.4.3 Bonds 848
22.4.4 Advance payments and retentions 849
22.4.5 Insurances 851
22.4.6 Project closeout 851
22.5 Terms and conditions of contract 851
22.5.1 Time, cost and quality 851
22.5.2 Basic types of contract 852
22.5.3 Standard terms and conditions of contract 854
22.5.4 Key clauses 858
22.6 Tendering 861
22.6.1 Choosing the contractor 861
22.6.2 Estimating 861
22.6.3 Tender evaluation 863
22.7 Model forms of contract – exercise 864
Appendix A: Project definition/questionnaire 866
Appendix B: Bidding checklist 892
Chapter 23 Distribution Planning 896
23.1 Introduction 896
23.2 Definitions 896
23.2.1 Demand or average demand 897
23.2.2 Maximum demand (MD) 898
23.2.3 Demand factor 899
23.2.4 Utilization factor (UF) 899
23.2.5 Load factor (LDF) 899
23.2.6 Diversity factor (DF) 900
23.2.7 Coincident factor (CF) 901
23.2.8 Load diversity 902
23.2.9 Loss factor (LSF) 902
23.2.10 Load duration 907
23.2.11 Loss equivalent hours 907
23.2.12 Peak responsibility factor (PRF) 909
23.3 Load forecasting 910
23.3.1 Users of load forecasts 910
23.3.2 The preparation of load forecasts 911
23.3.3 The micro load forecast 911
23.3.4 The macro load forecast 914
23.3.5 Nature of the load forecast 915
23.4 System parameters 917
23.4.1 Distribution feeder arrangements 917
23.4.2 Voltage drop calculations 918
23.4.3 Positive sequence resistance 921
23.4.4 Inductive reactance 921
23.4.5 Economic loading of distribution feeders and transformers 922
23.4.6 System losses 923
23.5 System reliability 925
23.5.1 Introduction 925
23.5.2 Reliability functions 926
23.5.3 Predictability analysis 930
23.6 Drawings and materials take off 935
Chapter 24 Power Quality – Harmonics in Power Systems 936
24.1 Introduction 936
24.2 The nature of harmonics 938
24.2.1 Introduction 938
24.2.2 Three phase harmonics 938
24.3 The generation of harmonics 939
24.3.1 General 939
24.3.2 Transformers 939
24.3.3 Converters 940
24.3.4 The thyristor bridge 940
24.3.5 Railway and tramway traction systems 942
24.3.6 Static VAr compensators and balancers 944
24.4 The effects of harmonics 946
24.4.1 Heating effects of harmonics 946
24.4.2 Harmonic overvoltages 946
24.4.3 Resonances 946
24.4.4 Interference 948
24.5 The limitation of harmonics 949
24.5.1 Harmonic filters 949
24.5.2 Capacitor detuning 953
24.6 Ferroresonance and subharmonics 953
24.6.1 Introduction 953
24.6.2 A physical description of ferroresonance 954
24.6.3 Subharmonics 957
24.6.4 Interharmonics 957
24.7 Harmonic studies 958
24.7.1 The requirement 958
24.7.2 The studies 959
24.7.3 Measurement 960
24.8 Case studies 960
References 960
Chapter 25 Power Quality – Voltage Fluctuations 962
25.1 Introduction 962
25.2 The nature and cause of voltage disturbances in power systems 962
25.2.1 Short-term interruptions and voltage dips and peaks 962
25.2.2 Voltage fluctuations 966
25.2.3 Voltage flicker 966
25.2.4 Slow-voltage fluctuations 967
25.2.5 Voltage unbalance 967
25.2.6 Step-change events 968
25.3 Solutions 968
25.3.1 Energy storage 968
25.3.2 Balancing 969
25.3.3 Static VAr compensators 969
25.3.4 The STATCOM 971
25.4 Case study 971
References 973
Chapter 26 Fundamentals 974
26.1 Introduction 974
26.2 Symbols and nomenclature 974
26.2.1 Symbols 974
26.2.2 Units and conversion tables 975
26.3 Alternating quantities 980
26.4 Vector representation 983
26.5 Vector algebra 988
26.5.1 The j operator 988
26.5.2 Exponential vector format 989
26.5.3 Polar co-ordinate vector format 990
26.5.4 Algebraic operations on vectors 990
26.5.5 The h operator 991
26.6 Sequence components 991
26.6.1 Theoretical background 991
26.6.2 Calculation methodology and approximations 993
26.6.3 Interpretation 994
26.7 Network fault analysis 995
26.7.1 Introduction 995
26.7.2 Fundamental formulae 995
26.7.3 Simplified network reduction example 1000
26.8 Design optimization 1006
26.8.1 Introduction 1006
26.8.2 Technical problems 1007
26.8.3 Loss reduction 1011
26.8.4 Communication link gain or attenuation 1019
26.8.5 Reactive compensation 1020
26.8.6 Power factor correction calculation procedures 1023
References 1027
Index 1030
A 1030
B 1030
C 1031
D 1032
E 1032
F 1033
G 1033
H 1033
I 1034
J 1034
K 1034
L 1034
M 1035
N 1035
O 1035
P 1035
Q 1036
R 1036
S 1037
T 1038
U 1039
V 1039
W 1039
X 1039
Y 1039
Z 1039