IEC TR 62681:2022

IEC TR 62681 ®
Edition 2.0 2022-05
TECHNICAL
REPORT
colour
inside
Electromagnetic performance of high voltage direct current (HVDC) overhead
transmission lines
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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
...