IEC TR 62681:2022

Electromagnetic performance of high voltage direct current (HVDC) overhead transmission lines

IEC TR 62681:2022 provides general guidance on the electromagnetic environment issues of HVDC overhead transmission lines. It concerns the major parameters adopted to describe the electromagnetic properties of an HVDC overhead transmission line, including electric fields, ion current, magnetic fields, radio interference, and audible noise generated as a consequence of such effects. If the evaluation method and/or criteria of electromagnetic properties are not yet regulated, engineers in different countries can refer to this document to:
- support/guide the electromagnetic design of HVDC overhead transmission lines,
- limit the influence on the environment within acceptable ranges, and
- optimize engineering costs.

General Information

• Status: Published
• Publication Date: 24-May-2022
• ICS: 29.240.20 - Power transmission and distribution lines
• Technical Committee: TC 115 - High Voltage Direct Current (HVDC) transmission for DC voltages above 100 kV
• Drafting Committee: WG 3 - TC 115/WG 3
• Current Stage: PPUB - Publication issued
• Start Date: 09-Jun-2022
• Completion Date: 25-May-2022

Relations

• Revises: IEC TR 62681:2014 - Electromagnetic performance of high voltage direct current (HVDC) overhead transmission lines
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC TR 62681 ®
Edition 2.0 2022-05
TECHNICAL
REPORT
colour
inside
Electromagnetic performance of high voltage direct current (HVDC) overhead
transmission lines
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

IEC Secretariat Tel.: [phone]
3, rue de Varembé [e-mail]
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

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IEC TR 62681 ®
Edition 2.0 2022-05
TECHNICAL
REPORT
colour
inside
Electromagnetic performance of high voltage direct current (HVDC) overhead
transmission lines
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.240.20 ISBN 978-2-8322-3130-2
– 2 – IEC TR 62681:2022 © IEC 2022
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 9
2 Normative references . 9
3 Terms and definitions . 9
4 Electric field and ion current . 10
4.1 Description of the physical phenomena . 10
4.2 Calculation methods . 14
4.2.1 General . 14
4.2.2 Semi-analytic method . 15
4.2.3 Finite element method . 17
4.2.4 BPA method . 18
4.2.5 Empirical methods of EPRI . 18
4.2.6 Recent progress . 19
4.3 Experimental data . 20
4.3.1 General . 20
4.3.2 Instrumentation and measurement methods . 20
4.3.3 Experimental results for electric field and ion current . 22
4.3.4 Discussion . 22
4.4 Implication for human and nature . 23
4.4.1 General . 23
4.4.2 Static electric field . 23
4.4.3 Research on space charge . 24
4.4.4 Scientific review . 29
4.5 Design practice of different countries . 31
5 Magnetic field . 32
5.1 Description of physical phenomena . 32
5.2 Magnetic field of HVDC transmission lines . 32
6 Radio interference . 33
6.1 Description of radio interference phenomena of HVDC transmission system . 33
6.1.1 General . 33
6.1.2 Physical aspects of DC corona . 33
6.1.3 Mechanism of formation of a noise field of DC line. 34
6.1.4 Characteristics of radio interference from DC line . 34
6.1.5 Factors influencing the RI from DC line . 35
6.2 Calculation methods . 37
6.2.1 EPRI empirical formula . 37
6.2.2 IREQ empirical method . 38
6.2.3 CISPR bipolar line RI prediction formula . 39
6.3 Experimental data . 40
6.3.1 Measurement apparatus and methods . 40
6.3.2 Experimental results for radio interference . 40
6.4 Criteria of different countries . 40
7 Audible noise . 41
7.1 Basic principles of audible noise . 41

7.2 Description of physical phenomena . 43
7.2.1 General . 43
7.2.2 Lateral profiles . 44
7.2.3 Statistical distribution . 47
7.2.4 Influencing factors . 48
7.2.5 Effect of altitude above sea level . 50
7.2.6 Concluding remarks . 50
7.3 Calculation methods . 50
7.3.1 General . 50
7.3.2 Theoretical analysis of audible noise propagation . 50
7.3.3 Empirical formulas of audible noise . 51
7.3.4 Semi-empirical formulas of audible noise . 52
7.3.5 Concluding remarks . 55
7.4 Experimental data . 55
7.4.1 Measurement techniques and instrumentation . 55
7.4.2 Experimental results for audible noise . 55
7.5 Design practice of different countries . 56
7.5.1 General . 56
7.5.2 The effect of audible noise on people . 56
7.5.3 The audible noise level and induced complaints . 56
7.5.4 Limit values of audible noise of HVDC transmission lines in different
countries . 60
7.5.5 General national noise limits . 60
Annex A (informative) Experimental results for electric field and ion current. 62
A.1 Bonneville Power Administration ±500 kV HVDC transmission line . 62
A.2 FURNAS ±600 kV HVDC transmission line . 62
A.3 Manitoba Hydro ±450 kV HVDC transmission line . 63
A.4 Hydro-Québec – New England ±450 kV HVDC transmission line . 65
A.5 IREQ test line study of ±450 kV HVDC line configuration . 66
A.6 HVTRC test line study of ±400 kV HVDC line configuration . 67
A.7 Test study in China . 68
Annex B (informative) Experimental results for radio interference . 71
B.1 Bonneville power administration’s 1 100 kV direct current test project . 71
B.1.1 General . 71
B.1.2 Lateral profile . 71
B.1.3 Influence of conductor gradient . 72
B.1.4 Percent cumulative distribution . 73
B.1.5 Influence of wind . 75
B.1.6 Spectrum . 75
B.2 Hydro-Québec institute of research . 77
B.2.1 General . 77
B.2.2 Cumulative distribution . 77
B.2.3 Spectrum . 78
B.2.4 Lateral profiles . 78
B.3 DC lines of China . 79
Annex C (informative) Experimental results for audible noise . 82
Bibliography . 86

– 4 – IEC TR 62681:2022 © IEC 2022
Figure 1 – Monopolar and bipolar space charge regions of an HVDC transmission line [1] . 11
Figure 2 – Lateral profile of magnetic field on the ground of ±800 kV HVDC lines . 33
Figure 3 – The corona current I and radio interference magnetic field H . 34
Figure 4 – RI tolerance tests: reception quality as a function of signal-to-noise ratio . 41
Figure 5 – Attenuation of different weighting networks used in audible-noise
measurements [16] . 42
Figure 6 – Comparison of typical audible noise frequency spectra [131] . 44
Figure 7 – Lateral profiles of the AN . 45
Figure 8 – Lateral profiles of the AN from a bipolar
...

IEC TR 62681 ®
Edition 2.0 2022-05
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Electromagnetic performance of high voltage direct current (HVDC) overhead
transmission lines
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

IEC Secretariat Tel.: [phone]
3, rue de Varembé [e-mail]
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform IEC Products & Services Portal - products.iec.ch
The advanced search enables to find IEC publications by a Discover our powerful search engine and read freely all the
variety of criteria (reference number, text, technical publications previews. With a subscription you will always
committee, …). It also gives information on projects, replaced have access to up to date content tailored to your needs.
and withdrawn publications.
Electropedia - www.electropedia.org
IEC Just Published - webstore.iec.ch/justpublished
The world's leading online dictionary on electrotechnology,
Stay up to date on all new IEC publications. Just Published
containing more than 22 300 terminological entries in English
details all new publications released. Available online and
and French, with equivalent terms in 19 additional languages.
once a month by email.
Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Customer Service Centre - webstore.iec.ch/csc

If you wish to give us your feedback on this publication or
need further assistance, please contact the Customer Service
Centre: [e-mail].
IEC TR 62681 ®
Edition 2.0 2022-05
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Electromagnetic performance of high voltage direct current (HVDC) overhead
transmission lines
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.240.20 ISBN 978-2-8322-3163-0

– 2 – IEC TR 62681:2022 RLV © IEC 2022
CONTENTS
FOREWORD . 7
INTRODUCTION . 9
1 Scope . 10
2 Normative references . 10
3 Terms and definitions . 10
4 Electric field and ion current . 11
4.1 Description of the physical phenomena . 11
4.2 Calculation methods . 15
4.2.1 General . 15
4.2.2 Semi-analytic method . 16
4.2.3 Finite element method . 18
4.2.4 BPA method . 19
4.2.5 Empirical methods of EPRI . 19
4.2.6 Recent progress . 20
4.3 Experimental data . 21
4.3.1 General . 21
4.3.2 Instrumentation and measurement methods . 21
4.3.3 Experimental results for electric field and ion current . 23
4.3.4 Discussion . 23
4.4 Implication for human and natural environment nature . 24
4.4.1 General . 24
4.4.2 Static electric field . 24
4.4.3 Research on space charge . 25
4.4.4 Scientific review . 30
4.5 Design practice of different countries . 32
5 Magnetic field . 33
5.1 Description of physical phenomena . 33
5.2 Magnetic field of HVDC transmission lines . 33
6 Radio interference (radio noise) . 34
6.1 Description of radio interference phenomena of HVDC transmission system . 34
6.1.1 General . 34
6.1.2 Physical aspects of DC corona . 35
6.1.3 Mechanism of formation of a noise field of DC line. 35
6.1.4 Characteristics of radio interference from DC line . 36
6.1.5 Factors influencing the RI from DC line . 37
6.2 Calculation methods . 39
6.2.1 EPRI empirical formula . 39
6.2.2 IREQ empirical method . 40
6.2.3 CISPR bipolar line RI prediction formula . 42
5.2.4 Comparison of different prediction formula .
6.3 Experimental data . 42
6.3.1 Measurement apparatus and methods . 42
6.3.2 Experimental results for radio interference . 43
6.4 Criteria of different countries . 43
7 Audible noise . 44

7.1 Basic principles of audible noise . 44
7.2 Description of physical phenomena . 45
7.2.1 General . 45
7.2.2 Lateral profiles . 47
7.2.3 Statistical distribution . 50
7.2.4 Influencing factors . 51
7.2.5 Effect of altitude above sea level . 53
7.2.6 Concluding remarks . 53
7.3 Calculation methods . 53
7.3.1 General . 53
7.3.2 Theoretical analysis of audible noise propagation . 54
7.3.3 Empirical formulas of audible noise . 54
7.3.4 Semi-empirical formulas of audible noise . 55
6.3.5 CEPRI (China) research results .
7.3.5 Concluding remarks . 59
7.4 Experimental data . 59
7.4.1 Measurement techniques and instrumentation . 59
7.4.2 Experimental results for audible noise . 60
7.5 Design practice of different countries . 60
7.5.1 General . 60
7.5.2 The effect of audible noise on people . 60
7.5.3 The audible noise level and induced complaints . 60
7.5.4 Limit values of audible noise of HVDC transmission lines in different

countries . 64
7.5.5 Recommended General national noise level limits . 65
6.5.6 Main conclusion .
Annex A (informative) Experimental results for electric field and ion current. 67
A.1 Bonneville Power Administration ±500 kV HVDC transmission line . 67
A.2 FURNAS ±600 kV HVDC transmission line . 67
A.3 Manitoba Hydro ±450 kV HVDC transmission line . 68
A.4 Hydro-Québec – New England ±450 kV HVDC transmission line . 70
A.5 IREQ test line study of ±450 kV HVDC line configuration . 71
A.6 HVTRC test line study of ±400 kV HVDC line configuration . 72
A.7 Test study in China . 74
Annex B (informative) Experimental results for radio interference . 76
B.1 Bonneville power administration’s 1 100 kV direct current test project . 76
B.1.1 General . 76
B.1.2 Lateral profile . 76
B.1.3 Influence of conductor gradient . 78
B.1.4 Percent cumulative distribution . 79
B.1.5 Influence of wind . 80
B.1.6 Spectrum . 81
B.2 Hydro-Québec institute of research . 82
B.2.1 General . 82
B.2.2 Cumulative distribution . 82
B.2.3 Spectrum . 83
B.2.4 Lateral profiles . 84
B.2.5 Cumulative distribution under different voltage .
B.3 DC lines of China . 85

– 4 – IEC TR 62681:2022 RLV © IEC 2022
Annex C (informative) Experimental results for audible noise . 89
Bibliography . 93

Figure 1 – Unipolar Monopolar and bipolar space charge regions of an HVDC
transmission line [1] . 13
Figure 2 – Lateral profile of magnetic field on the ground of ±800 kV HVDC lines . 34
Figure 3 – The corona I and radio interference magnetic field H . 35
Figure
...