IEC TR 62001-1:2021

High-voltage direct current (HVDC) systems - Guidance to the specification and design evaluation of AC filters - Part 1: Overview

IEC TR 62001-1:2021 deals with the specification and design evaluation of AC side harmonic performance and AC side filters for HVDC schemes. It is intended to be primarily for the use of the utilities and consultants who are responsible for issuing the specifications for new HVDC projects and evaluating designs proposed by prospective suppliers. This document provides guidance on the specifications of AC filters for high-voltage direct current (HVDC) systems with line-commutated converters and filter performance calculation. The scope of this document covers AC side filtering for the frequency range of interest in terms of harmonic distortion and audible frequency disturbances. Where the term "HVDC converter" or "HVDC station" is referred to without qualification, in this document, it is understood to refer to LCC technology. It excludes filters designed to be effective in the power line carrier (PLC) and radio interference spectra. This edition includes the following significant technical changes with respect to the previous edition:
- general updating of the document to reflect changes in practice;
- 10.2.4 on fuseless capacitors has been transferred to IEC TR 62001-4;
- Clause 11 on future developments has been expanded;
- 10.3.3 and Annex F on voltage sourced converters have been deleted as their content is covered by IEC TR 62543.

General Information

• Status: Published
• Publication Date: 12-Jul-2021
• ICS: 29.200 - Rectifiers. Convertors. Stabilized power supply
• Technical Committee: SC 22F - Power electronics for electrical transmission and distribution systems
• Drafting Committee: MT 21 - TC 22/SC 22F/MT 21
• Current Stage: PPUB - Publication issued
• Start Date: 26-Jul-2021
• Completion Date: 13-Jul-2021

Relations

• Revises: IEC TR 62001-1:2016 - High-voltage direct current (HVDC) systems - Guidance to the specification and design evaluation of AC filters - Part 1: Overview
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC TR 62001-1 ®
Edition 2.0 2021-07
TECHNICAL
REPORT
colour
inside
High-voltage direct current (HVDC) systems – Guidance to the specification and
design evaluation of AC filters –
Part 1: Overview
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 Central Office 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.

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(IEV) online.
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If you wish to give us your feedback on this publication or
need further assistance, please contact the Customer Service
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IEC TR 62001-1 ®
Edition 2.0 2021-07
TECHNICAL
REPORT
colour
inside
High-voltage direct current (HVDC) systems – Guidance to the specification and

design evaluation of AC filters –

Part 1: Overview
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.200 ISBN 978-2-8322-9986-9

– 2 – IEC TR 62001-1:2021  IEC 2021
CONTENTS
FOREWORD . 7
INTRODUCTION . 9
1 Scope . 10
2 Normative references . 10
3 Terms and definitions . 10
4 Outline of specifications of AC filters for HVDC systems . 11
4.1 General . 11
4.2 Boundaries of responsibility . 12
4.3 Scope of studies . 14
4.4 Scope of supply . 14
4.5 Technical data to be supplied by contractor . 15
4.6 Alternative proposals by bidders . 15
5 Permissible distortion limits . 16
5.1 General . 16
5.2 Voltage distortion . 17
5.2.1 General . 17
5.2.2 Definitions of performance criteria . 17
5.2.3 Discussion and recommendations . 18
5.2.4 Determination of limits . 18
5.2.5 Pre-existing harmonic levels . 21
5.2.6 Relaxed limits for short term and infrequent conditions . 22
5.2.7 Treatment of interharmonic frequencies . 22
5.3 Distortion limits pertaining to the HV and EHV network equipment . 23
5.3.1 HVAC transmission system equipment . 23
5.3.2 Harmonic currents in synchronous machines . 23
5.3.3 Nearby HVDC installations . 24
5.4 Telephone interference . 24
5.4.1 General . 24
5.4.2 Causes of telephone interference . 24
5.4.3 Definitions of performance criteria . 24
5.4.4 Discussion . 25
5.4.5 Determination of limits . 25
5.4.6 Pre-existing harmonic levels . 27
5.4.7 Limits for temporary conditions . 27
5.5 Special criteria . 28
6 Harmonic generation . 28
6.1 General . 28
6.2 Converter harmonic generation . 28
6.2.1 Idealized conditions . 28
6.2.2 Realistic conditions . 30
6.3 Calculation methodology . 32
6.3.1 General . 32
6.3.2 Harmonic currents for performance, rating and other calculations . 32
6.3.3 Combining harmonics from different converter bridges. 33
6.3.4 Consistent sets . 33
6.3.5 Harmonic generation for different DC power ranges . 34

6.4 Sensitivity of harmonic generation to various factors . 35
6.4.1 Direct current, control angle and commutation overlap . 35
6.4.2 Effect of asymmetries on characteristic harmonics . 35
6.4.3 Converter equipment parameter tolerances . 35
6.4.4 Tap steps . 36
6.4.5 Theoretically cancelled harmonics . 36
6.4.6 Negative and zero sequence voltages . 36
6.4.7 Converter transformer saturation . 37
6.4.8 Harmonic interaction across the converter . 37
6.4.9 Back-to-back systems . 38
6.5 Externally generated harmonics . 38
7 Filter arrangements . 38
7.1 Overview . 38
7.2 Advantages and disadvantages of typical filters . 39
7.3 Classification of filter types . 40
7.4 Tuned filters . 40
7.4.1 Single tuned filters . 40
7.4.2 Double tuned filters . 42
7.4.3 Triple tuned filters . 44
7.5 Damped filters . 45
7.5.1 Single tuned damped filters . 45
7.5.2 Double tuned damped filters . 48
7.6 Choice of filters . 49
8 Filter performance calculation . 50
8.1 Calculation procedure . 50
8.1.1 General . 50
8.1.2 Input data . 50
8.1.3 Methodology . 50
8.1.4 Calculation of converter harmonic currents . 51
8.1.5 Selection of filter types and calculation of their impedances . 52
8.1.6 Calculation of performance . 52
8.2 Detuning and tolerances . 53
8.2.1 General . 53
8.2.2 Detuning factors . 54
8.2.3 Resistance variations . 55
8.2.4 Modelling . 55
8.3 Network impedance for performance calculations . 55
8.3.1 General . 55
8.3.2 Network modelling using impedance envelopes . 56
8.3.3 Sector diagram . 57
8.3.4 Circle diagram . 58
8.3.5 Discrete polygons . 59
8.3.6 Zero-sequence impedance modelling . 61
8.3.7 Detailed modelling of AC network for performance calculation . 61
8.4 Outages of filter banks and sub-banks . 62
8.5 Considerations of probability . 63
8.6 Flexibility regarding compliance . 65
8.7 Ratings of the harmonic filter equipment . 65
9 Filter switching and reactive power management . 66

– 4 – IEC TR 62001-1:2021  IEC 2021
9.1 General . 66
9.2 Reactive power interchange with AC network . 66
9.2.1 General .
...

IEC TR 62001-1 ®
Edition 2.0 2021-07
REDLINE VERSION
TECHNICAL
REPORT
colour
inside
High-voltage direct current (HVDC) systems – Guidance to the specification and
design evaluation of AC filters –
Part 1: Overview
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 Central Office 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 online collection - oc.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 22 000 terminological entries in English
details all new publications released. Available online and
and French, with equivalent terms in 18 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 62001-1 ®
Edition 2.0 2021-07
REDLINE VERSION
TECHNICAL
REPORT
colour
inside
High-voltage direct current (HVDC) systems – Guidance to the specification and
design evaluation of AC filters –
Part 1: Overview
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.200 ISBN 978-2-8322-4530-9

– 2 – IEC TR 62001-1:2021 RLV  IEC 2021
CONTENTS
FOREWORD . 8
INTRODUCTION . 2
1 Scope . 11
2 Normative references . 11
3 Terms and definitions . 11
4 Outline of specifications of AC filters for HVDC systems . 12
4.1 General . 12
4.2 Boundaries of responsibility . 13
4.3 Scope of studies . 15
4.4 Scope of supply . 16
4.5 Technical data to be supplied by contractor . 16
4.6 Alternative proposals by bidders . 17
5 Permissible distortion limits . 17
5.1 General . 17
5.2 Voltage distortion . 18
5.2.1 General . 18
5.2.2 Definitions of performance criteria . 18
5.2.3 Discussion and recommendations . 19
5.2.4 Determination of limits . 19
5.2.5 Pre-existing harmonic levels . 22
5.2.6 Relaxed limits for short term and infrequent conditions . 23
5.2.7 Treatment of interharmonic frequencies . 23
5.3 Distortion limits pertaining to the HV and EHV network equipment . 24
5.3.1 HVAC transmission system equipment . 24
5.3.2 Harmonic currents in synchronous machines . 24
5.3.3 Nearby HVDC installations . 25
5.4 Telephone interference . 25
5.4.1 General . 25
5.4.2 Causes of telephone interference . 25
5.4.3 Definitions of performance criteria . 26
5.4.4 Discussion . 26
5.4.5 Determination of limits . 26
5.4.6 Pre-existing harmonic levels . 28
5.4.7 Limits for temporary conditions . 28
5.5 Special criteria . 29
6 Harmonic generation . 29
6.1 General . 29
6.2 Converter harmonic generation . 30
6.2.1 Idealized conditions . 30
6.2.2 Realistic conditions . 31
6.3 Calculation methodology . 33
6.3.1 General . 33
6.3.2 Harmonic currents for performance, rating and other calculations . 34
6.3.3 Combining harmonics from different converter bridges. 34
6.3.4 Consistent sets . 35
6.3.5 Harmonic generation for different DC power ranges . 36

6.4 Sensitivity of harmonic generation to various factors . 37
6.4.1 Direct current, control angle and commutation overlap . 37
6.4.2 Effect of asymmetries on characteristic harmonics . 37
6.4.3 Converter equipment parameter tolerances . 37
6.4.4 Tap steps . 38
6.4.5 Theoretically cancelled harmonics . 38
6.4.6 Negative and zero phase sequence voltages . 38
6.4.7 Converter transformer saturation . 39
6.4.8 Harmonic interaction across the converter . 39
6.4.9 Back-to-back systems . 39
6.5 Externally generated harmonics . 40
7 Filter arrangements . 40
7.1 Overview . 40
7.2 Advantages and disadvantages of typical filters . 41
7.3 Classification of filter types . 42
7.4 Tuned filters . 42
7.4.1 Single tuned filters . 42
7.4.2 Double tuned filters . 44
7.4.3 Triple tuned filters . 46
7.5 Damped filters . 47
7.5.1 Single tuned damped filters . 47
7.5.2 Double tuned damped filters . 50
7.6 Choice of filters . 51
8 Filter performance calculation . 52
8.1 Calculation procedure . 52
8.1.1 General . 52
8.1.2 Input data . 52
8.1.3 Methodology . 52
8.1.4 Calculation of converter harmonic currents . 53
8.1.5 Selection of filter types and calculation of their impedances . 54
8.1.6 Calculation of performance . 54
8.2 Detuning and tolerances . 55
8.2.1 General . 55
8.2.2 Detuning factors . 56
8.2.3 Resistance variations . 57
8.2.4 Modelling . 57
8.3 Network impedance for performance calculations . 57
8.3.1 General . 57
8.3.2 Network modelling using impedance envelopes . 58
8.3.3 Sector diagram . 59
8.3.4 Circle diagram . 60
8.3.5 Discrete polygons . 61
8.3.6 Zero-sequence impedance modelling . 63
8.3.7 Detailed modelling of AC network for performance calculation . 63
8.4 Outages of filter banks and sub-banks . 64
8.5 Considerations of probability . 65
8.6 Flexibility regarding compliance . 67
8.7 Ratings of the harmonic filter equipment . 67
9 Filter switching and reactive power management . 68

– 4 – IEC TR 62001-1:2021 RLV  IEC 2021
9.1 General . 68
9.2 Reactive power interchange with AC network . 68
9.2.1 General . 68
9.2.2 Impact on reactive comp
...