Insulation Coordination for Power Systems (Power Engineering (Willis))

Insulation Coordination for Power Systems......Page 1
Series Introduction......Page 4
Preface......Page 6
1 GOALS......Page 10
2 LINE INSULATION COORDINATION......Page 11
3 STATION INSULATION COORDINATION......Page 13
5 TWO METHODS OF INSULATION COORDINATION......Page 14
6 REFERENCES......Page 15
Contents......Page 8
2 TYPES OF INSULATION......Page 16
Contents......Page 0
3.1 BIL-Basic Lightning Impulse Insulation Level......Page 17
3.3 Standard Waveshapes......Page 18
3.4 Statistical vs. Conventional BILIBSL......Page 19
3.5 Tests to \"Prove\" the BIL and BSL......Page 21
3.6 Standard BILs and BSLs......Page 23
3.7 CFO and ICFO--- \"ProbabilRituyn Tests\"......Page 24
3.8 CFO......Page 29
3.9 Chopped Wave Tests or Time-Lag Curves......Page 30
4 NONSTANDARD ATMOSPHERIC CONDITIONS......Page 31
5 GENERATION OF VOLTAGES IN THE LABORATORY......Page 37
6.2 Apparatus Standards and Effects of Altitude......Page 41
7.2 CFO and nf/CFO......Page 42
7.4 Atmospheric Correction Factors......Page 43
9 PROBLEMS......Page 44
1 INTRODUCTION......Page 46
2 SWITCHING IMPULSE STRENGTH OF TOWERS......Page 47
2.1 Wave Front......Page 52
2.2 Insulator Length......Page 54
2.3 Strike Distance......Page 55
2.4 Standard Deviation of Flashover......Page 58
2.5 Wet/Dry Conditions......Page 59
3 SUMMARY-INSULATION STRENGTH OF TOWERS......Page 60
4 DETERMINISTIC DESIGN OF TRANSMISSION LINES......Page 62
5 SWITCHING IMPULSE STRENGTH OF POST INSULATORS......Page 63
6 A GENERAL APPROACH TO THE SWITCHING IMPULSE STRENGTH......Page 67
6.1 The Conductor-Window Gap-Center Phase......Page 69
6.2 Conductor-Crossarm-Outside Phase......Page 70
6.4 Conductor-Lateral Structure......Page 71
6.5 Rod-Rod Structure......Page 72
For Rod-Rod Gaps......Page 73
7.2 CFO of Insulators and Gaps-Present Day Data......Page 74
7.3 LI Strength of Towers......Page 79
7.5 Time-Lag (Volt-Time) Curves......Page 82
8 LIGHTNING IMPULSE STRENGTH OF WOOD AND PORCELAIN......Page 84
9 LIGHTNING IMPULSE STRENGTH OF FIBERGLASS......Page 90
10 EFFECT OF TAIL ON CFO......Page 91
11 LI FLASHOVER MECHANISM......Page 92
12 POWER FREQUENCY......Page 93
13 COMPARISON WITH IEC......Page 95
14 SUMMARY......Page 96
15 REFERENCES......Page 97
16 PROBLEMS......Page 99
1 INTRODUCTION......Page 103
2 THE CONCEPT-USING HISTOGRAMS OF SWITCHING OVERVOLTAGES......Page 104
3.1 With Strength Distribution for One Tower......Page 109
3.2 Stress and Strength Both Normal-For One Tower......Page 111
3.3 More Than One Tower......Page 112
3.4 Voltage Profile......Page 113
4.1 Case Peaks or Phase Peaks......Page 114
5.1 Gaussian Distribution......Page 116
5.2 The Extreme Value Positive Skew Distribution......Page 118
6 SENSITIVITY ANALYSIS OF SSFOR......Page 120
6.1 Strength-Stress ratio V3/E2......Page 121
6.4 /CFO......Page 123
6.5 SOV Profile......Page 124
7.1 Brown\'s Method......Page 125
8.1 Insulation Strength, Gaussian......Page 129
8.2 Gaussian SOV Distribution......Page 130
8.3 Extreme Value Positive Skew SOV Distribution......Page 131
9 EXAMPLES......Page 132
10 ESTIMATING THE SSFOR FROM V3/E2......Page 134
11 EFFECT OF WIND ON !-STRINGS......Page 135
12 FACTORS OF DESIGN......Page 140
1 3.1 Strength Characteristics for n Parallel Insulations......Page 141
13.3 Stress-Strength and Estimating the SSFOR......Page 143
13.4 Estimating the Strike Distance......Page 145
15 PROBLEMS......Page 146
1 INTRODUCTION......Page 149
2 PHASE-PHASE INSULATION STRENGTH......Page 150
2.1 The Alpha Method......Page 151
2.2 The V+-V- Method......Page 153
2.3 Correlating the Methods......Page 155
2.4 Phase-Phase and Phase-Ground......Page 156
Effect of So on CFOg......Page 157
The Value of KL......Page 158
3 PHASE-PHASE SWITCHING OVERVOLTAGES......Page 159
3.1 Gaussian SOV Distributions, Vp and V+......Page 160
3.3 The Correlation Coefficients......Page 161
4.1 Phase-Phase SSFOR......Page 162
4.2 Combined Phase-Phase and Phase-Ground SSFOR......Page 163
4.4 Reversed Parameters......Page 165
5.1 General......Page 166
5.2 With SOVs Density as Normal or Gaussian......Page 167
6 ADAPTING BROWN\'S SIMPLIFIED METHOD......Page 168
6.1 Example 1......Page 169
6.3 Reversed Parameters......Page 170
6.4 Sensitivity......Page 171
8 INTERNAL INSULATIONS......Page 172
11 REFERENCES......Page 173
12 PROBLEMS......Page 174
2 PHASE-GROUND INSULATION COORDINATION......Page 176
2.2 Number of Insulations in Parallel......Page 177
2.5 Estimating the SSFOR and Strike Distance......Page 178
Clearances or Strike Distances......Page 179
Apparatus......Page 180
2.8 Equations-Review......Page 182
2.9......Page 183
2.10......Page 184
2.11 Phase-Ground Insulation Coordination with Arresters......Page 185
2.12......Page 188
2.13 Transformer and Transformer Bushing......Page 190
The Alpha Method......Page 191
The V+-V- Method......Page 192
3.3 Combined Distribution of Vz......Page 194
3.4 Estimating Method......Page 195
3.5......Page 196
3.7......Page 197
4 CFO AND KL AS A FUNCTION OF Sp/h......Page 199
6.1 IEC Methods: Phase-Ground [3]......Page 200
6.2 IEC Method - Phase-Phase [3]......Page 202
6.3 IEC Clearances [3,7]......Page 203
8 PROBLEMS......Page 206
1 INTRODUCTION-GENERAL BACKGROUND [I-31......Page 207
2 THE STROKE MECHANISM......Page 209
3 TYPES OF LIGHTNING FLASHES......Page 214
4 PARAMETERS OF THE FLASH......Page 215
5 BERGER\'S DATA......Page 217
6 THE SEARCH FOR THE CREST CURRENT DISTRIBUTION......Page 221
6.1 Negative Upward Flashes......Page 224
6.2 Positive Flashes......Page 225
7 MULTIPLE STROKES (STROKE MULTIPLICITY)......Page 226
8 LIGHTNING INCIDENCE......Page 227
9 GEOMETRIC MODEL OF THE LAST STEP OF THE LIGHTNING STROKE......Page 233
10 STRIKING DISTANCE EQUATIONS......Page 237
11 ERIKSSON\'S MODIFIED GEOMETRIC MODEL......Page 239
12.1 From Field Data......Page 240
12.2 Comparison, Field Data vs. Geometric Model......Page 242
13 INCREASE IN CURRENT MAGNITUDE WITH HEIGHT......Page 243
15 SUMMARY......Page 246
16 REFERENCES......Page 248
17 PROBLEMS......Page 251
2 BACKGROUND......Page 253
3.1 Basic Concept......Page 256
3.3 The Maximum Shielding Failure Current Im......Page 259
3.4 Shielding Failure Flashover Rate SFFOR......Page 261
3.5 The \"Perfect\" Shielding Angle......Page 262
4 ERIKSSON\'S MODIFIED MODEL......Page 263
4.1 The SFFOR......Page 264
4.2 Perfect Shielding and Maximum Shielding Failure Current......Page 265
5 SENSITIVITY ANALYSIS-PERFECT SHIELDING......Page 266
7 SELECTION OF THE SHIELDING ANGLE BASED ON SFFOR......Page 269
8.1 Terrain-Hillside Effects......Page 272
8.3 Terrain-Hilltops......Page 273
8.5 An Example......Page 274
9 A SIMPLIFIED METHOD OF CALCULATING THE SFFOR......Page 275
10 SUBSEQUENT STROKES-A PROBLEM......Page 277
1 1.3 Currents to Shield Wires......Page 279
13 PRESENTLY USED SHIELDING ANGLES......Page 280
14 CONCLUSIONS......Page 281
15 REFERENCES......Page 283
16 PROBLEMS......Page 285
2 BASIS OF DESIGN......Page 287
3 STRIKING DISTANCE EQUATIONS......Page 290
3.3 Brown-Whitehead-CIGRE Equations......Page 291
4 SHIELDING USING SHIELD WIRES......Page 292
5.1 One Mast......Page 295
5.2 Two Masts......Page 296
5.3 Three Masts......Page 301
5.4 More than Three Masts......Page 305
5.5 Special Cases......Page 308
7 MASTS OR SHIELD WIRES......Page 313
9 CONCLUSIONS......Page 314
1 0.1 Design Current......Page 315
10.3 General Equations......Page 316
10.7 Definition of Rc......Page 317
11 REFERENCES......Page 319
12 PROBLEMS......Page 321
1 CONCEPT: SURGE IMPEDANCE......Page 325
1.5 The Micro-System......Page 327
2.1 General......Page 328
2.2 The Use of Thevenin\'s Theorem......Page 329
2.5 The n-Line Station......Page 330
2.6 Line-Cable Junction......Page 332
3 A CALCULATION METHOD: THE LATTICE DIAGRAM......Page 333
4 STROKE TO TOWER......Page 335
5.1 Reduction of the Crest Voltage at the Struck Tower......Page 339
5.2 Reduction of the Tail......Page 341
6.1 General: Separation Distance......Page 343
6.2 Voltage at Transformer for an n-Line Station......Page 345
6.3 Eb for an n-Line Station......Page 348
6.4 Arrester Lead Length......Page 349
6.5 Power Frequency Voltage......Page 351
6.6 Arrester Current......Page 353
7.1 General......Page 355
7.2 Equivalent Surge Impedance......Page 356
7.3 The Coupling Factor......Page 357
7.4 Coupling Factor Between Two Ground Wires and One Phase Conductor......Page 358
8.1......Page 359
8.2......Page 360
9 TOWER SURGE IMPEDANCE......Page 363
10.1 Introduction......Page 366
General......Page 367
At the Corona Inception Voltage......Page 373
Above Corona Start Voltage......Page 374
Value of Parameters......Page 375
Corona Inception Voltage......Page 376
10.3 Surge Impedance......Page 377
10.4 Coupling Factor......Page 378
12 PROBLEMS......Page 380
1 INTRODUCTION AND REVIEW......Page 385
2 A FIRST ESTIMATE OF THE BACKFLASH RATE......Page 387
3.1 Flashovers Within the Span......Page 389
4 IMPULSE RESISTANCE OF GROUND ELECTRODES......Page 391
4.1 Concentrated Grounds-Ground Rods......Page 392
4.2 Counterpoises......Page 394
4.3 Grounding Considerations......Page 397
5 EFFECT OF POWER FREQUENCY VOLTAGE AND NUMBER OF PHASES......Page 399
6 FINDING THE NONSTANDARD CFO, CFONS......Page 402
7 TIME TO CREST OF THE STROKE CURRENT, tf......Page 405
9 CALCULATING THE BFR-THE CIGRE METHOD......Page 408
10 A SIMPLIFIED METHOD......Page 409
1 1 A SENSITIVITY ANALYSIS......Page 410
1 1.3 Effect of Corona......Page 411
1 1.4 Effect of Decrease of Resistance from Ro vs. Ri......Page 412
1 1.5 One vs. Two Shield Wires......Page 413
1 1.6 Underbuilt Shield or Ground Wire......Page 414
1 1.8 BFRs for 34.5 kV Lines......Page 417
1 1.1 0 Comparison: CIGRE vs. IEEE Methods......Page 419
1 2.3 Double-Circuit Flashover Rates......Page 423
12.5 Alternate Flashover Paths and Their Critical Flashover Voltage......Page 425
12.6 Flashover vs. Outage......Page 426
12.7 Distribution of Footing Resistance......Page 427
13.3 Rogue Tower......Page 428
13.4 Use of Surge Arresters......Page 429
14 CONCLUSIONS......Page 430
15 BACKGROUND......Page 431
16 REFERENCES......Page 432
17 PROBLEMS......Page 434
1 FLASHOVERS WITHIN THE SPAN......Page 436
2 FLASHOVERS AT THE TOWER CAUSED BY STROKES TO THE SHIELD WIRE......Page 438
3 REFERENCES......Page 442
1 GROUNDROD......Page 444
2 THE HEMISPHERE ELECTRODE......Page 446
3 THE ROD ELECTRODE......Page 448
4 THE SIMPLIFICATION......Page 449
5 RESULTS AND OTHER INVESTIGATIONS......Page 450
6 REFERENCES......Page 451
1 COUNTERPOISES......Page 452
2.1 One Ground Rod......Page 453
3 EXAMPLES......Page 454
5 SENSITIVITY......Page 455
6 REFERENCES......Page 457
10-Appendix 4 Effect of Power Frequency Voltage and Number of Phases......Page 458
1 Kia = Kib = Kic =Ki......Page 464
2 KIA= KIB, KIiC< < KIA......Page 467
5 FINDING Kpf FOR PRACTICAL CASES......Page 468
5.2 Vertical Configuration......Page 469
6 CONCLUSION......Page 470
1 DESIGNING FOR AN MTBF......Page 472
2.1 Review of the Backflash......Page 475
2.2 The Incoming Surge......Page 477
2.3 Effect of Corona......Page 480
2.4 Estimating the Incoming Surge for an MTBS......Page 481
2.5 An Example......Page 483
2.7 Selecting the Incoming Surge......Page 485
2.8 Ameliorating Measures......Page 486
3.1 Voltage at the Struck Point......Page 487
3.3 Estimating the Incoming Surge for an MTBS......Page 489
4 SIMPLIFIED AND QUICK ESTIMATE......Page 493
5 APPLYING THE SURGE TO THE STATION......Page 494
7 THE INCOMING SURGE FROM SUBSEQUENT STROKES......Page 496
8 PROTECTION OF THE OPEN BREAKER......Page 499
9.1 IEEEIAIEE Papers......Page 501
9.2 CIGRE and IEC......Page 503
11 REFERENCES......Page 505
12 PROBLEMS......Page 506
1 INTRODUCTION......Page 507
1.1 General Characteristics......Page 508
1.2 Arrester Classes......Page 509
1.3 Construction types......Page 510
1.4 Voltage Ratings......Page 511
2. DURABILITYICAPABILITY TESTS......Page 512
2.2 Low-Current, Long-Duration......Page 513
2.4 Pressure Relief \"Short-CircuityyF ailure......Page 514
2.6 Switching Impulse Energy......Page 515
2.7 Temporary Overvoltages......Page 518
2.8 General Energy Capability......Page 520
3.3 Switching Impulse Protective Level-Sl......Page 522
3.5 Effect of Time to Crest......Page 523
3.6 Arrester Models......Page 524
4.1 Maximum System Voltage......Page 526
4.2 Switching Surge Energy......Page 527
4.3 TOVs-Temporary Overvoltages......Page 529
4.4 Parallel or Multicolumn Arresters......Page 532
6 CALCULATING THE DISCHARGE VOLTAGE AND CURRENT FOR LIGHTNING IMPULSES......Page 533
6.1 Arrester at End of Line......Page 535
6.2 For an n-Line Station......Page 536
6.3 Effect of Reflections from Open End-of-Line......Page 537
6.4 Effect of Reflections from Struck Point......Page 540
6.5 Combining Both Effects......Page 543
6.6 Shielding Failures......Page 548
7.1 Selection of the Arrester MCOV......Page 549
7.2 Arrester Currents......Page 550
8 IEC STANDARDS......Page 551
8.1 Durabilitylcapability Tests......Page 552
8.2 Protective Characteristics......Page 553
8.4 Comparison of IEEE and IEC......Page 554
9 REFERENCES......Page 556
10 PROBLEMS......Page 557
12-Appendix 1 Protective Characteristics of Arresters......Page 558
1 INTRODUCTION......Page 566
2 THE STRESS-CREST VOLTAGE AT EQUIPMENT......Page 570
Effect of Arrester Voltage-Current Characteristics......Page 572
For a Long Separation Distance......Page 573
Voltage at the Transformer......Page 576
Single-Line Station......Page 580
More Than One Line......Page 583
Summary with Effect of the Arrester Lead Length......Page 585
Effect of Arrester Characteristics~AS pecial Case [13]......Page 586
3.1 Safety Factors......Page 589
Self-Restoring Insulations......Page 590
Self-Restoring Insulations......Page 591
Non-Self-Restoring Insulation......Page 592
A New Transformer Insulation Strength Curve......Page 599
Phase-Ground and Phase-Phase Air Clearances......Page 601
5 APPLICATION OF SIMPLIFIED METHOD......Page 602
5.1 Single-Line Station......Page 603
5.2 A Two-Line Station......Page 608
All Lines in Service......Page 609
Contingency Conditions......Page 613
5.3 A Nonsymmetrical Station Layout......Page 615
6 GAS-INSULATED STATIONS......Page 616
7 COMPARISON WITH IEEE......Page 622
8 COMPARISON WITH IEC......Page 623
9.1 Voltage with CT = 0, An Open Circuit......Page 625
9.2 Voltage with Transformer Capacitance CT......Page 626
10 CONCLUSIONS......Page 627
11 REFERENCES......Page 628
12 PROBLEMS......Page 629
1 TRANSFORMER SURGE CAPACITANCE......Page 633
3 REFERENCES......Page 634
1 INTRODUCTION......Page 635
2 THE CONCEPT OF A SEVERITY INDEX......Page 637
3 ALTERNATE METHODS OF ESTIMATING THE SEVERITY INDEX......Page 638
4 DETERMINING THE CONSTANTS OF THE LPM AND DE METHODS......Page 641
4.2 The DE Method with V0 Not Equal to Zero......Page 642
5 COMPARISON OF METHODS......Page 643
7 TIME DURATION REQUIREMENTS......Page 646
11 REFERENCES......Page 647
1 INTRODUCTION......Page 649
2 APPLICATION CONCERNS AND CRITERIA......Page 650
4.1 Shielding Failure, Stroke to Phase Conductor......Page 651
4.2 Stroke to Tower......Page 655
5 11 5 kV UNSHIELDED LINE......Page 657
6.1 Stroke to Ground Wires at Towers......Page 661
6.2 Stroke to Phase Conductor at Tower, with Ground Wires or Neutral......Page 663
6.3 Stroke to Phase Conductor, No Ground Wire......Page 665
7.1 Stroke to Conductor, No Ground Wire or Neutral......Page 667
7.2 Stroke to Conductor with Ground Wire or Neutral......Page 670
7.3 Stroke to Ground Wire......Page 673
8.1 Stroke to Conductor, No Ground Wire or Neutral......Page 676
8.2 Stroke to Conductor with Ground Wire or Neutral......Page 677
8.3 Stroke to Ground Wire......Page 678
9.1 General......Page 679
REFERENCES......Page 680
11 PROBLEMS......Page 682
1 INTRODUCTION......Page 684
2 CALCULATION OF INDUCED VOLTAGES......Page 686
3 CONSIDERING THE NEUTRAL OR GROUND WIRE......Page 689
4 EFFECT OF NEARBY OBJECTS......Page 693
6 EXAMPLEÑEFFEC OF TREES OR FORESTS......Page 698
7 STRIKING DISTANCE EQUATIONS-A REVIEW......Page 700
8 PROTECTION AGAINST INDUCED VOLTAGES......Page 701
9 COMPARISON TO FIELD DATA......Page 702
10 SUMMARY AND CONCLUSIONS......Page 703
11 REFERENCES......Page 704
12 PROBLEMS......Page 705
1 INTRODUCTION......Page 707
2.2 The Direct Method of Selecting the Insulation......Page 708
2.3 Determining the Contamination Severity......Page 709
Test Methods......Page 710
General Results from Tests on Cap and Pin Insulators......Page 712
General Results from Tests on Station Insulation......Page 716
Other Results......Page 718
The Deterministic Method......Page 719
The Probabilistic Method......Page 721
2.7 Comparison-Number of Insulators......Page 722
2.8 Effect of Altitude......Page 723
2.1 0 IEC Recommendations......Page 724
3.1 Background......Page 726
3.2 Field Reports, SiR, and EPDM......Page 727
3.4 Mechanism of Flashover......Page 728
3.5 Test Methods......Page 729
3.6 Test Results......Page 731
3.7 Resistive Glaze......Page 732
4 METHODS TO IMPROVE PERFORMANCE......Page 733
5.1 Icing......Page 734
6 REFERENCES......Page 735
7 PROBLEMS......Page 738
1 INTRODUCTION......Page 739
2.1 Reference Heights and Minimum Clearances to 22-kV Phase-Ground......Page 740
2.3 The Alternate Method for Voltages Greater than 98 kVPhase-Ground......Page 741
2.4 The Statistical Switching Overvoltage......Page 743
2.6 Comparison with Methods of Chapters 2 and 3......Page 744
3.2 The Alternate Method......Page 746
3.3 Example of Tower Clearances......Page 748
4 TRANSMISSION LINE WORKING CLEARANCE......Page 750
5 CLEARANCES IN STATIONS......Page 754
6 CONCLUSIONS......Page 757
7 REFERENCES......Page 758
1 INTRODUCTION......Page 759
2 COMPARISON OF DESIGN......Page 760
2.2 Switching Overvoltages......Page 761
2.3 Power Frequency Voltage......Page 762
2.4 Comparison......Page 763
3 COMPARISON BASED ON SOR......Page 765
5 REFERENCES......Page 767
Appendix Computer Programs for This Book......Page 768