Lightning Protection
Wednesday, November 17, 2010
Contents
List of contributors xxvii
Preface xxix
Acknowledgements xxxi
1 Benjamin Franklin and lightning rods 1
E. Philip Krider
1.1 A Philadelphia story 3
1.2 The French connection 5
1.3 Experiments in colonial America 6
1.4 First protection system 7
1.5 Improvements 9
1.6 ‘Snatching lightning from the sky’ 12
Acknowledgement 13
References 13
2 Lightning parameters of engineering interest 15
Vernon Cooray and Mahendra Fernando
2.1 Introduction 15
2.2 Electric fields generated by thunderclouds 19
2.3 Thunderstorm days and ground flash density 23
2.4 Number of strokes and time interval between strokes
in ground flashes25
2.4.1 Number of strokes per flash 28
2.4.2 Interstroke interval 30
2.5 Number of channel terminations in ground flashes 31
2.6 Occurrence of surface flash over 34
2.7 Lightning leaders 36
2.7.1 Speed of stepped leaders 36
2.7.2 Speed of dart leaders 37
2.7.3 Electric fields generated by stepped leaders 39
2.7.4 Electric fields generated by dart leaders 40
2.7.5 Speed of connecting leaders 44
2.7.6 Currents in connecting leaders 45
2.8 Current parameters of first and subsequent returnstrokes 47
2.8.1 Berger’s measurements 50
2.8.2 Garbagnati and Piparo’s measurements 51
2.8.3 Eriksson’s measurements 51
2.8.4 Analysis of Andersson and Eriksson 53
2.8.5 Measurements of Takami and Okabe 53
2.8.6 Measurements of Visacro and colleagues 54
2.8.7 Summary of current measurements 54
2.9 Statistical representation of lightning current parameters 55
2.9.1 Correlation between different current parameters57
2.9.2 Effect of tower height 60
2.9.3 Mathematical representation of current waveforms67
2.9.3.1 Current waveform recommended by the CIGRE study group67
2.9.3.2 Analytical form of the current used in the
International Electrotechnical
Commission standard 70
2.9.3.3 Analytical expression of Nucci and colleagues 71
2.9.3.4 Analytical expression of Diendorfer and Uman 71
2.9.3.5 Analytical expression of Delfino and colleagues72
2.9.3.6 Analytical expression of Cooray and colleagu72
2.9.4 Current wave shapes of upward-initiated flashes 72
2.10 Electric fields from first and subsequent strokes74
2.11 Peak electric radiation fields of first and subsequent strokes 81
2.12 Continuing currents 84
2.13 M-components 88
References 88
3 Rocket-triggered lightning and new insights into lightning
protection gained from triggered-lightning experiments97
V.A. Rakov
3.1 Introduction 97
3.2 Triggering techniques 98
3.2.1 Classical triggering 98
3.2.2 Altitude triggering 103
3.2.3 Triggering facility at Camp Blanding, Florida 105
3.3 Overall current waveforms 107
3.3.1 Classical triggering 107
3.3.2 Altitude triggering 109
3.4 Parameters of return-stroke current waveforms 110
3.5 Return-stroke current peak versus grounding conditions 122
3.6 Characterization of the close lightning electromagnetic environment128
3.7 Studies of interaction of lightning with various objects and systems131
3.7.1 Overhead power distribution lines 131
3.7.1.1 Nearby strikes 131
3.7.1.2 Direct strikes 135
3.7.2 Underground cables 143
3.7.3 Power transmission lines 143
3.7.4 Residential buildings 144
3.7.5 Airport runway lighting system 144
3.7.6 Miscellaneous experiments 149
3.8 Concluding remarks 150
References 150
Bibliography 159
4 Attachment of lightning flashes to grounded structures 165
Vernon Cooray and Marley Becerra
4.1 Introduction 165
4.1.1 The protection angle method 166
4.1.2 The electro-geometrical method 168
4.1.3 The rolling sphere method 170
4.1.4 The mesh method 175
4.2 Striking distance to flat ground 176
4.2.1 Golde 177
4.2.2 Eriksson 177
4.2.3 Dellera and Garbagnati 179
4.2.4 Cooray and colleagues 179
4.2.5 Armstrong and Whitehead 180
4.3 Striking distance to elevated structures 182
4.3.1 Positive leader discharges 183
4.3.2 Leader inception models 186
4.3.2.1 The critical radius concept 186
4.3.2.2 Rizk’s generalized leader inception equation 190
4.3.2.3 Critical streamer length concept 194
4.3.2.4 Bazelyan and Raizer’s empirical leader model 195
4.3.2.5 Lalande’s stabilization field equation 196
4.3.2.6 The self-consistent leader inception model of
Becerra and Cooray197
4.4 The leader progression model 212
4.4.1 The basic concept of the leader progression model 212
4.4.2 The leader progression model of Eriksson 212
4.4.3 The leader progression model of Dellera and
Garbagnati215
4.4.4 The leader progression model of Rizk 217
4.4.5 Attempts to validate the existing leader progression models 220
4.4.6 Critical overview of the assumptions of leader progression models223
4.4.6.1 Orientation of the stepped leader 223
4.4.6.2 Leader inception criterion 224
4.4.6.3 Parameters and propagation of the upward
connecting leader225
4.4.6.4 Effects of leader branches and tortuosity 226
4.4.6.5 Thundercloud electric field 226
4.4.7 Becerra and Cooray leader progression model 227
4.4.7.1 Basic theory 227
4.4.7.2 Self-consistent lightning interception model
(SLIM)231
4.5 Non-conventional lightning protection systems 239
4.5.1 The early streamer emission concept 240
4.5.1.1 Experimental evidence in conflict with the concept of ESE 241
4.5.1.2 Theoretical evidence in conflict with the concept of ESE 243
4.5.2 The concept of dissipation array systems (DAS) 251
4.5.2.1 Experimental evidence against dissipation arrays 253
5 Protection against lightning surges 269
Rajeev Thottappillil and Nelson Theethayi
5.1 Introduction 269
5.1.1 Direct strike to power lines 269
5.1.2 Lightning activity in the vicinity of networks 270
5.2 Characteristics of lightning transients and their
impact on systems 273
5.2.1 Parameters of lightning current important for
surge protection design 274
5.2.1.1 Peak current 274
5.2.1.2 Charge transferred 274
5.2.1.3 Prospective energy 275
5.2.1.4 Waveshape 276
5.2.2 Parameters of lightning electric and magnetic
fields important for surge protection design276
5.3 Philosophy of surge protection 278
5.3.1 Surge protection as part of achieving
electromagnetic compatibility 278
5.3.1.1 Conductor penetration through a shield 279
5.3.2 Principle of surge protection 280
5.3.2.1 Gas discharge tubes (spark gaps) 282
5.3.2.2 Varistors 285
5.3.2.3 Diodes and thyristors 286
5.3.2.4 Current limiters 288
5.3.2.5 Isolation devices 290
5.3.2.6 Filters 291
5.3.2.7 Special protection devices used in power distribution networks 293
5.4 Effects of parasitic elements in surge protection and filter components 294
5.4.1 Capacitors 295
5.4.2 Inductors 297
5.4.3 Resistors 298
5.4.3.1 Behaviour of resistors at various frequencies 299
5.5 Surge protection coordination 302
References 303
6 External lightning protection system 307
Christian Bouquegneau
6.1 Introduction 307
6.2 Air-termination system 308
6.2.1 Location of air-terminations on the structure 308
6.2.1.1 Positioning of the air-termination system utilizing the rolling sphere method310
6.2.1.2 Positioning of the air-termination system utilizing the mesh method311
6.2.1.3 Positioning of the air-termination system utilizing the protection angle method313
6.2.1.4 Comparison of methods for the positioning of the air-termination system316
6.2.2 Construction of air-termination systems 316
6.2.3 Non-conventional air-termination systems 320
6.3 Down-conductor system 320
6.3.1 Location and positioning of down-conductors on the structure 320
6.3.2 Construction of down-conductor systems 322
6.3.3 Structure with a cantilevered part 325
6.3.4 Joints, connections and test joints in down-conductors 326
6.3.5 Lightning equipotential bonding 328
6.3.6 Current distribution in down-conductors 330
6.4 Earth-termination system 330
6.4.1 General principles 330
6.4.2 Earthing arrangements in general conditions 332
6.4.3 Examples of earthing arrangements in common small structures 335
6.4.4 Special earthing arrangements 341
6.4.4.1 Earth electrodes in rocky and sandy soils 341
6.4.4.2 Earth-termination systems in large areas 341
6.4.4.3 Artificial decrease of earth resistance 342
6.4.5 Effect of soil ionization and breakdown 343
6.4.6 Touch voltages and step voltages 343
6.4.6.1 Touch voltages 343
6.4.6.2 Step voltages 344
6.4.8 Measurement of soil resistivity and earth resistances 345
6.4.8.1 Measurement of soil resistivity 345
6.4.8.2 Measurement of earth resistances 348
6.5 Selection of materials 348
Acknowledgements 352
References 353
7 Internal lightning protection system 355
Peter Hasse and Peter Zahlmann
7.1 Damage due to lightning and other surges 355
7.1.1 Damage in hazardous areas 357
7.1.2 Lightning damage in city areas 357
7.1.3 Damage to airports 360
7.1.4 Consequences of lightning damage 361
7.2 Protective measures 361
7.2.1 Internal lightning protection 363
7.2.1.1 Equipotential bonding in accordance with IEC 60364-4-41 and -5-54 363
7.2.1.2 Equipotential bonding for a low-voltage system 364
7.2.1.3 Equipotential bonding for information technology system 364
7.2.2 Lightning protection zones concept 365
7.2.3 Basic protection measures: earthing magnetic shielding and bonding 366
7.2.3.1 Magnetic shielding 366
7.2.3.2 Cable shielding 369
7.2.3.3 Equipotential bonding network 371
7.2.3.4 Equipotential bonding on the boundaries of lightning protection zones 373
7.2.3.5 Equipotential bonding at the boundary of LPZ 0A and LPZ 2 380
7.2.3.6 Equipotential bonding on the boundary of LPZ 1 and LPZ 2 and higher 383
7.2.3.7 Coordination of the protective measures at various LPZ boundaries 385
7.2.3.8 Inspection and maintenance of LEMP protection 388
7.3 Surge protection for power systems: power supply systems (within the scope of the lightning protection zones concept according to IEC 62305-4) 389
7.3.1 Technical characteristics of SPDs 391
7.3.1.1 Maximum continuous voltage UC 391
7.3.1.2 Impulse current Iimp 392
7.3.1.3 Nominal discharge current In 392
7.3.1.4 Voltage protection level Up 392
7.3.1.5 Short-circuit withstand capability 392
7.3.1.6 Follow current extinguishing capability at UC (Ifi) 392
7.3.1.7 Follow current limitation (for spark-gap based SPDs class I) 393
7.3.1.8 Coordination 393
7.3.1.9 Temporary overvoltage 393
7.3.2 Use of SPDs in various systems 393
7.3.3 Use of SPDs in TN systems 396
7.3.4 Use of SPDs in TT systems 398
7.3.5 Use of SPDs in IT systems 401
7.3.6 Rating the lengths of connecting leads for SPDs 401
7.3.6.1 Series connection (V-shape) in accordance with IEC 60364-5-53 402
7.3.6.2 Parallel connection system in accordance with
IEC 60364-5-53 403
7.3.6.3 Design of the connecting lead on the earth side 405
7.3.6.4 Design of the phase-side connecting cables 406
7.3.7 Rating of cross-sectional areas and backup protection of SPDs410
7.3.7.1 Selectivity to the protection of the installation 416
7.4 Surge protection for telecommunication systems 417
7.4.1 Procedure for selection and installation of arresters:example BLITZDUCTOR CT 417
7.4.1.1 Technical data 418
7.4.2 Measuring and control systems 421
7.4.2.1 Electrical isolation using optocouplers 422
7.5 Examples for application 423
7.5.1 Lightning and surge protection of wind turbines 423
7.5.1.1 Positive prognoses 424
7.5.1.2 Danger resulting from lightning effects 424
7.5.1.3 Frequency of lightning strokes 424
7.5.1.4 Standardization 425
7.5.1.5 Protection measures 425
7.5.1.6 Shielding measures 426
7.5.1.7 Earth-termination system 426
7.5.2 Lightning and surge protection for photovoltaic systems and solar power plants 428
7.5.2.1 Lightning and surge protection for photovoltaic systems428
7.5.2.2 Lightning and surge protection for solar power plants 434
7.5.3 Surge protection for video surveillance systems 438
7.5.3.1 Video surveillance systems 439
7.5.3.2 Choice of SPDs 439
Bibliography 441
8 Risk analysis 443
Z. Flisowski and C. Mazzetti
8.1 General considerations 443
8.2 General concept of risk due to lightning 445
8.3 Number of strikes to a selected location 447
8.4 Damage probabilities 452
8.5 Simplified practical approach to damage probability457
8.6 Question of relative loss assessment 458
8.7 Concept of risk components 459
8.8 Standardized procedure of risk assessment 461
8.8.1 Basic relations 461
8.8.2 Evaluation of risk components 464
8.8.3 Risk reduction criteria 468
8.9 Meaning of subsequent strokes in a flash 470
8.10 Final remarks and conclusions 471
References 472
9 Low-frequency grounding resistance and lightning protection 475
Silverio Visacro
9.1 Introduction 475
9.2 Basic considerations about grounding systems 475
9.3 The concept of grounding resistance 476
9.4 Grounding resistance of some simple electrode arrangements 479
9.5 Relation of the grounding resistance to the experimental response of electrodes to lightning currents482
9.6 Typical arrangements of grounding electrodes for some relevant applications and their lightning-protection-related requirements487
9.6.1 Transmission lines 487
9.6.2 Substations 490
9.6.3 Lightning protection systems 494
9.6.4 Overhead distribution lines 496
9.7 Conclusion 497
References 499
10 High-frequency grounding 503
Leonid Grcev
10.1 Introduction 503
10.2 Basic circuit concepts 503
10.3 Basic field considerations 506
10.4 Frequency-dependent characteristics of the soil 509
10.5 Grounding modelling for high frequencies 511
10.6 Frequency-dependent grounding behaviour 514
10.7 Frequency-dependent dynamic grounding behaviour 521
10.8 Relation between frequency-dependent and non-linear
grounding behaviour 526
References 527
11 Soil ionization 531
Vernon Cooray
11.1 Introduction 531
11.2 Critical electric field necessary for ionization in soil 534
11.3 Various models used in describing soil ionization 536
11.3.1 Ionized region as a perfect conductor 536
11.3.2 Model of Liew and Darveniza 537
11.3.2.1 Application of the model to a single driven rod 538
11.3.3 Model of Wang and colleagues 540
11.3.4 Model of Sekioka and colleagues 543
11.3.5 Model of Cooray and colleagues 545
11.3.5.1 Mathematical description 546
11.3.5.2 Model parameters 548
11.4 Conclusions 550
References 550
12 Lightning protection of low-voltage networks 553
Alexandre Piantini
12.1 Introduction 553
12.2 Low-voltage networks 554
12.2.1 Typical configurations and earthing practices 554
12.2.2 Distribution transformers 558
12.2.3 Low-voltage power installations 564
12.3 Lightning surges on low-voltage systems 568
12.3.1 Direct strikes 568
12.3.2 Cloud discharges 570
12.3.3 Indirect strikes 571
12.3.3.1 Calculation of lightning-induced voltages 573
12.3.3.2 Sensitivity analysis 578
12.3.4 Transference from the medium-voltage line 601
12.3.4.1 Direct strikes 601
12.3.4.2 Indirect strikes 605
12.4 Lightning protection of LV networks 611
12.4.1 Distribution transformers 612
12.4.2 Low-voltage power installations 614
12.5 Concluding remarks 624
References
13 Lightning protection of medium voltage lines 635
C.A. Nucci and F. Rachidi
13.1 Introduction 635
13.2 Lightning strike incidence to distribution lines 636
13.2.1 Expected number of direct lightning strikes 638
13.2.2 Shielding by nearby objects 639
13.3 Typical overvoltages generated by direct and indirect lightning strikes 640
13.3.1 Direct overvoltages 640
13.3.2 Induced overvoltages 642
13.4 Main principles in lightning protection of distribution lines 645
13.4.1 Basic impulse insulation level and critical impulse flashover voltage 646
13.4.2 Shield wires 648
13.4.3 Protective devices 650
13.4.3.1 General considerations using protective devices 650
13.4.3.2 Spark gaps 651
13.4.3.3 Surge arresters 652
13.4.3.4 Capacitors 653
13.5 Lightning protection of distribution systems 653
13.5.1 Effect of the shield wire 653
13.5.2 Effect of surge arresters 655
13.5.3 Lightning performance of MV distribution lines 660
13.5.3.1 Effect of soil resistivity 662
13.5.3.2 Effect of the presence of shield wires 662
13.5.3.3 Effect of the presence of surge arresters 666
Appendix A13 Procedure to calculate the lightning
performance of
distribution lines according to IEEE Std. 1410-2004 (from Reference 4)666
Appendix B13 The LIOV-Monte Carlo (LIOV–MC) procedure to calculate the lightning performance of distribution lines (from Reference 56)668
Appendix C13 The LIOV code: models and equations 670
C13.1 Agrawal and colleagues field-to-transmission line coupling equations extended to the case of
multiconductor lines above a lossy earth 671
C13.2 Lightning-induced voltages on distribution networks: LIOV code interfaced
with EMTPrv 675
Acknowledgements 675
References 675
xvi Contents
14 Lightning protection of wind turbines 681
Troels Soerensen
14.1 Introduction 681
14.2 Nature of the lightning threat to wind turbines 686
14.3 Statistics of lightning damage to wind turbines 687
14.4 Risk assessment and cost–benefit evaluation 688
14.5 Lightning protection zoning concept 691
14.6 Earthing and equipotential bonding 693
14.7 Protection of wind turbine components 695
14.7.1 Blades 695
14.7.1.1 Blades with carbon fibre 699
14.7.1.2 Guidelines, quality assurance and test methods700
14.7.2 Hub 702
14.7.3 Nacelle 703
14.7.4 Tower 703
14.7.5 Bearings and gears 704
14.7.6 Hydraulic systems 705
14.7.7 Electrical systems, control and communication systems 706
14.7.7.1 Electrical systems 707
14.7.7.2 Generator circuit 707
14.7.7.3 Medium-voltage system 709
14.7.7.4 Auxiliary power circuit(s) 709
14.7.7.5 Control and communication systems 711
14.8 Wind farm considerations 713
14.9 Off-shore wind turbines 714
14.10 Lightning sensors and registration methods 716
14.11 Construction phase and personnel safety 717
References 718
15 Lightning protection of telecommunication towers 723
G.B. Lo Piparo
15.1 Lightning as a source of damage to broadcasting stations 723
15.1.1 General 723
15.1.2 Injury to people 725
15.1.3 Physical damage 725
15.1.3.1 Thermal effects 725
15.1.3.2 Electrodynamic effects 726
15.1.4 Failure of internal electrical and electronic systems 726
15.2 Effects of lightning flashes to the broadcasting station 726
15.2.1 Effects of lightning flashes to the antenna support structure 726
15.2.1.1 Lightning current flowing through external conductive parts and lines connected to the station 729
15.2.1.2 Potential differences between different parts of the earth-termination system of the station 730
15.3 Lightning flashes affecting the power supply system 731
15.3.1 Power supply by overhead lines 731
15.3.1.1 Lightning flashes to an overhead line 731
15.3.1.2 Lightning flash to ground near an overhead line733
15.3.1.3 Surges at the point of entry of an overhead line in the station 733
15.3.1.4 Overhead line connected directly to the transformer 734
15.3.1.5 Buried cable connection between the overhead line and the transformer734
15.3.2 Power supply by underground cable 735
15.3.3 Transfer of overvoltages across the transformer735
15.4 The basic principles of lightning protection 736
15.4.1 The protection level to be provided 736
15.4.2 Basic criteria for protection of stations 737
15.4.3 Protection measures 738
15.4.4 Procedure for selection of protection measures739
15.4.5 Implementation of protection measures 739
15.5 Erection of protection measures to reduce injury of living beings 742
15.5.1 Protection measures against step voltages 742
15.5.2 Protection measures against touch-voltages 742
15.6 Erection of the LPS to reduce physical damage 743
15.6.1 Air-termination system 743
15.6.2 Down-conductors system 743
15.6.3 Earth-termination system 745
15.6.3.1 Earth-termination system for stations with an autonomous power supply 747
15.6.3.2 Earth-termination system for stations powered by an external source 749
15.6.4 Protection against corrosion 753
15.6.5 Earthing improvement 753
15.6.6 Foundation earth electrode 754
15.7 Potential equalization to reduce failures of electrical and electronic systems757
15.7.1 Potential equalization for the earth-termination system of the station 757
15.7.2 Potential equalization for the antenna support structure 761
15.7.3 Potential equalization for the equipment within the building 761
15.7.4 Potential equalization for metallic objects outside the building 763
15.8 Screening to reduce failures of electrical and electronic systems 763
15.8.1 Screening of circuits within the building 763
15.8.2 Circuits of the station entering the building 764
15.9 Coordinated SPD protection system to reduce failures of electrical and electronic systems 766
15.9.1 Selection of SPDs with regard to voltage protection level 766
15.9.2 Selection of SPD with regard to location and to discharge current766
15.9.3 Installation of SPDs in a coordinated SPD protection system 767
15.9.3.1 Protective distance lP 767
15.9.3.2 Induction protective distance lPi 768
15.10 Protection of lines and services entering the station 768
15.10.1 Overhead lines 769
15.10.2 Screened cables 770
15.11 Arrangement of power supply circuits 771
15.11.1 Stations supplied at high voltage 771
15.11.2 Stations supplied at low voltage 773
15.11.3 Stations with self-contained power supplies only 776
Annex A15: Surge testing of installations 776
A15.1 Simulation of surge phenomena 776
A15.1.1 General 776
A15.1.2 Tests for determining overvoltages due to lightning flashes to the antenna-support structure 777
A15.1.3 Determination of the transferred overvoltages 777
A15.1.4 Results 778
A15.2 Description of a typical test programme 779
A15.2.1 Introduction 779
A15.2.2 The power supply arrangements of the station 780
A15.2.3 The test equipment 781
A15.2.4 The test procedure and results 781
A15.2.4.1 Measurement of the overvoltages due to
lightning flashes to the antenna-support structure 783
A15.2.4.2 Measurement of the transferred overvoltages783
A15.3 Discussion of the results 784
A15.3.1 Lightning flashes to the antenna-supportstructure 786
A15.3.2 Overvoltages transferred by the power supply line 786
A15.4 Conclusions 787
Acknowledgements 787
References 787
16 Lightning protection of satellite launch pads 789
Udaya Kumar
16.1 Introduction 789
16.2 Structure of a rocket 790
16.3 Launch pad 791
16.3.1 Launch campaign and duration of exposure 792
16.4 Lightning threat to launch vehicle 792
16.4.1 Limitations of present-day knowledge in quantifying the risk793
16.5 Lightning protection systems 794
16.5.1 External protection 794
16.5.1.1 Brief description of some of the present protection schemes 796
16.5.2 Principles used for the design of the external protection system 798
16.5.2.1 Air termination network 798
16.5.2.2 Earth termination 799
16.5.2.3 Down-conductor system 799
16.5.3 Internal protection 799
16.5.3.1 Launch vehicle 799
16.5.3.2 Vehicle on launch pad 801
16.6 Weather launch commit criteria 802
16.7 Review of present status and suggested direction for further work 803
16.7.1 Attachment process 803
16.7.2 Lightning surge response 806
16.7.2.1 Earth termination 806
16.7.2.2 Down-conductor system 807
16.7.3 Weather launch commit criteria 813
16.8 Indirect effects 813
16.9 Protection of other supporting systems 814
16.10 On-site measurements 814
16.11 Summary 815
References 816
17 Lightning protection of structures with risk of fire and explosion 821 Arturo Galva´n Diego
17.1 Introduction 821
17.2 Tanks and vessels containing flammable materials 822
17.2.1 General 822
17.2.2 Risk assessment 824
17.2.3 Lightning protection measures 825
17.2.3.1 Air terminations 826
17.2.3.2 Equipotential bonding 828
17.2.3.3 A clean environment 829
17.2.3.4 Self-protecting system 829
17.2.3.5 Resume´ for lightning protection 830
17.3 Offshore oil platforms 830
17.3.1 General 830
17.3.2 Relevant standards 831
17.3.3 Risk assessment 832
17.3.4 Lightning protection measures 832
17.3.4.1 External lightning protection 832
17.3.4.2 Grounding system and common bonding network 834
17.3.4.3 Internal grounding system 835
17.3.4.4 Shielding 838
17.3.4.5 Location of SPD 839
References 839
18 Lightning and trees 843
Mahendra Fernando, Jakke Ma¨kela¨ and Vernon Cooray
18.1 Introduction 843
18.2 Strike and damage probability of lightning to trees
844
18.3 Types of lightning damage 846
18.3.1 Microscale damage 846
18.3.2 Macroscale damage 847
18.3.2.1 No physical damage 847
18.3.2.2 Bark-loss damage 849
18.3.2.3 Wood-loss damage 849
18.3.2.4 Explosive damage 849
18.3.2.5 Ignition 850
18.3.3 Other damage scenarios 852
18.3.3.1 Long-term propagation of damage 853
18.3.3.2 Group damage to trees 853
18.3.3.3 Damage to ground 853
18.3.3.4 Damage to vegetation 854
18.4 Protection of trees 854
18.5 Conclusions 855
Acknowledgements 855
References 855
19 Lightning warning systems 859
Martin J. Murphy, Kenneth L. Cummins and Ronald L. Holle
19.1 Introduction 859
19.2 Thunderstorm lifecycle and associated detection methods 860
19.2.1 Thunderstorm life cycle 860
19.2.1.1 Convective development and electrification 860
19.2.1.2 Early stages of lightning activity 861
19.2.1.3 Late stages of lightning activity 861
19.2.2 Associated detection methods 862
19.2.2.1 Detection of initial electrification 862
19.2.2.2 Single-point lightning detection sensors 863
19.2.2.3 Lightning detection networks 864
19.3 Examples of warning systems 864
19.3.1 Fixed-point warning applications 864
19.3.2 Storm-following algorithms 867
19.4 Warning system performance measures 869
19.4.1 Performance metrics 869
19.4.1.1 Performance metrics for fixed-point algorithms 870
19.4.1.2 Performance metrics for storm-following algorithms 873
19.4.2 Specific challenges at different stages of the warning problem 875
19.4.2.1 Lightning onset 875
19.4.2.2 Lightning cessation 876
19.5 Application of performance measures to cloud-to-ground warning systems879
19.5.1 Assessment of a fixed-point warning algorithm 879
19.5.1.1 Effects of lightning detection technology 879
19.5.1.2 Effects of algorithm configuration using a single detection technology 884
19.5.2 Lightning cessation in MCS cases 884
19.5.3 Radar applications for lightning onset in storm-following algorithms885
19.6 Assessing the risks 887
19.6.1 Decision making 887
19.6.2 Equipment protection application 891
9.6.3 Trade-offs between performance and risks for cloud-to-ground warning in safety applications 892
19.6.3.1 Personal and small-group warning 892
19.6.3.2 Large venue warning 893
References 894
20 Lightning-caused injuries in humans 901
Vernon Cooray, Charith Cooray and Christopher Andrews
20.1 Introduction 901
20.2 The different ways in which lightning can interact with humans 902
20.3 Different types of injuries 906
20.3.1 Injuries to the respiratory and cardiovascular system 906
20.3.2 Injuries to the eye 909
20.3.3 Ear 910
20.3.4 Nervous system 912
20.3.5 Skin and burn injuries 913
20.3.6 Psychological 914
20.3.7 Blunt injuries 914
20.3.8 Disability caused by lightning 915
20.3.9 Remote injuries 915
20.3.10 Lightning electromagnetic fields 917
20.4 Concluding remarks 920
References 920
21 Lightning standards 925
Fridolin Heidler and E.U. Landers
21.1 Introduction 925
21.2 Standardized lightning currents 926
21.2.1 Threat parameters of the lightning current 926
21.2.2 Current waveforms 928
21.2.3 Requirements for the current tests 930
21.3 Determination of possible striking points 931
21.3.1 Rolling sphere method 931
21.3.2 Mesh method 933
21.3.3 Protection angle method 933
21.4 The lightning protection system (LPS) 934
21.4.1 Air termination system 934
21.4.2 Down-conductor system 935
21.4.3 Earth termination system 935
21.4.4 Lightning equipotential bonding 937
21.4.5 Separation distance 938
21.5 The LEMP protection measures system (LPMS) 939
21.5.1 The lightning protection zones (LPZ) concept 939
21.5.2 Earthing system and bonding network 941
21.5.3 Line routing and shielding 942
21.5.4 Coordinated surge protection device application 942
21.5.5 Spatial magnetic shielding 942
21.6 Conclusions 944
References 946
22 High-voltage and high-current testing 947
Wolfgang Zischank
22.1 Introduction 947
22.2 Lightning test equipment 948
22.2.1 High-voltage impulse test generators 948
22.2.1.1 Single-stage impulse voltage circuits 950
22.2.1.2 Multistage impulse voltage circuits 953
22.2.2 High-current test generators 956
22.2.2.1 Simulation of first return stroke effects 957
22.2.2.2 Simulation of subsequent return stroke effects 967
22.2.2.3 Generation of long-duration currents 970
22.2.2.4 Current injection for direct effects testing 971
22.2.3 Indirect effects testing 972
22.3 Measurement techniques 974
22.3.1 Measurement of impulse voltages 974
22.3.2 Measurement of impulse currents 975
22.3.2.1 Resistive shunts 975
22.3.2.2 Rogowski coils 976
22.3.2.3 Current monitors 977
References 978
23 Return stroke models for engineering applications 981
Vernon Cooray
23.1 Introduction 981
23.2 Current propagation models (CP models) 983
23.2.1 Basic concept 983
23.2.2 Most general description 984
23.3 Current generation models (CG models) 986
23.3.1 Basic concept 986
23.3.2 Mathematical background 988
23.3.2.1 Evaluate Ib(t) given r(z), t(z) and v(z) 988
23.3.2.2 Evaluate t(z) given Ib(t), r(z) and v(z) 989
23.3.2.3 Evaluate r(z) given Ib(t), t(z) and v(z) 990
23.3.2.4 Evaluate v(z), given Ib(t), r(z) and t(z) 990
23.3.3 CG models in practice 990
23.3.3.1 Model of Wagner 991
23.3.3.2 Model of Heidler 991
23.3.3.3 Model of Hubert 992
23.3.3.4 Model of Cooray 993
23.3.3.5 Model of Diendofer and Uman 994
23.3.3.6 First modification of the Diendofer and Uman model by Thottappillil et al.996
23.3.3.7 Second modification of the Diendofer and Uman model by Thottappillil and Uman997
23.3.3.8 Model of Cooray 998
23.3.3.9 Model of Cooray and Rakov 999
23.3.3.10 Model of Cooray, Rakov and Montano 1000
23.4 Current dissipation models (CD Models) 1001
23.4.1 General description 1001
23.4.2 Mathematical background 1003
23.4.3 Cooray and Rakov model – a combination of current dissipation and current generation models 1004
23.5 Generalization of any model to the current generation type 1006
23.6 Generalization of any model to the current dissipation type 1008
23.7 Current dissipation models and the modified transmission line models 1009
23.8 Effect of ground conductivity 1010
23.9 Equations necessary to calculate the electric and magnetic fields 1012
23.10 Concluding remarks 1015
References 1016
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