IEC TS 63042-202:2021

IEC TS 63042-202 ®
Edition 1.0 2021-10
TECHNICAL
SPECIFICATION
colour
inside
UHV AC transmission systems –
Part 202: UHV AC Transmission line design
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IEC TS 63042-202 ®
Edition 1.0 2021-10
TECHNICAL
SPECIFICATION
colour
inside
UHV AC transmission systems –
Part 202: UHV AC Transmission line design

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.240.20 ISBN 978-2-8322-1035-7

– 2 – IEC TS 63042-202:2021 © IEC 2021
CONTENTS
FOREWORD . 10
1 Scope . 12
2 Normative references . 12
3 Terms and definitions . 13
4 Symbols and abbreviations . 13
5 UHV AC transmission line requirements . 14
5.1 General requirements . 14
5.2 Reliability requirements. 14
5.3 Electrical requirements . 14
5.4 Security requirements . 14
5.5 Safety requirements . 14
5.6 Environmental impact. 14
5.7 Economy . 14
6 Selection of clearance . 15
6.1 General . 15
6.2 Air gap, tower clearances (strike distance) . 15
6.2.1 Power frequency voltage . 15
6.2.2 Switching overvoltage . 15
6.2.3 Lightning overvoltage . 15
6.3 Phase to phase spacing (Horizontal, Vertical) . 16
6.4 Ground clearances – Statutory requirements, electric and magnetic field
limits . 16
6.5 Conductor-earth wire spacing, shielding angle – Lightning performance
criteria . 16
7 Insulation coordination, insulator and insulator string design . 17
7.1 General . 17
7.2 Insulation requirements – electrical design considerations . 17
7.3 Insulating materials, type of insulators . 17
7.4 Insulator string configurations for disc type insulators . 18
7.5 Mechanical design criteria of insulator strings and associated hardware
fittings . 19
8 Bundle-conductor selection . 19
8.1 General . 19
8.2 Conductor types . 19
8.3 Bundle conductor configurations . 20
8.3.1 Number of sub-conductors . 20
8.3.2 Bundle spacing . 20
8.4 Conductor bundle selection process . 20
8.4.1 Cross-section of conductor . 20
8.4.2 Conductor ampacity . 20
8.4.3 Requirements for electromagnetic environment . 21
8.4.4 Capital cost and loss evaluation . 21
8.5 Mechanical strength . 21
8.6 Conductor accessories . 22
8.6.1 General requirements for fittings . 22
8.6.2 Type and design features of link fittings, vibration dampers, spacers . 22
9 Earth wire/OPGW selection . 23

9.1 General . 23
9.2 Type of earth wire/OPGW . 23
9.3 Design Criteria/Requirements Specific to UHV Lines. 23
9.4 Induced voltages on earth wire . 23
10 Tower and foundation design . 24
10.1 General . 24
10.2 Tower classification . 24
10.2.1 General . 24
10.2.2 Conductor configuration . 24
10.2.3 Constructional features . 29
10.2.4 Line deviation angle . 29
10.2.5 Tower extensions . 30
10.2.6 Specific requirements . 30
10.3 Tower design . 30
10.3.1 General . 30
10.3.2 Selection of tower geometry based on electrical clearances . 30
10.3.3 Calculation of loads on tower . 31
10.3.4 Analysis using software . 31
10.3.5 Full scale tower testing . 32
10.3.6 Tower design methodology . 32
10.4 Foundation design . 33
10.4.1 General . 33
10.4.2 Open cast type foundations . 34
10.4.3 Raft type foundations . 34
10.4.4 Deep foundations (Pile/Well/Pier/Steel Anchor type) . 35
11 Environmental considerations . 35
11.1 General . 35
11.2 Electric field . 35
11.2.1 General . 35
11.2.2 Reference level of electric field . 35
11.2.3 Prediction of electric field . 36
11.2.4 Mitigation measures of electric field . 36
11.3 Magnetic field . 36
11.3.1 General . 36
11.3.2 Reference level of magnetic field . 36
11.3.3 Prediction of magnetic field . 36
11.3.4 Mitigation measures of magnetic field . 37
11.4 Corona noise (audible noise with corona discharge) . 37
11.4.1 General . 37
11.4.2 Characteristics of corona noise . 37
11.4.3 Reference level of corona noise . 37
11.4.4 Prediction of corona noise . 38
11.4.5 Mitigation measures of corona noise . 38
11.5 Radio interference with corona discharge . 38
11.5.1 General . 38
11.5.2 Characteristics of radio interference . 38
11.5.3 Reference level of radio interference . 39
11.5.4 Prediction of radio interference . 39
11.5.5 Mitigation measures of radio interference . 39

– 4 – IEC TS 63042-202:2021 © IEC 2021
11.6 Wind noise . 39
Annex A (informative) Experimental results and c
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