IEC TR 60919-1:2020

Performance of high-voltage direct current (HVDC) systems with line-commutated converters - Part 1: Steady-state conditions

IEC TR 60919-1:2020(E) provides general guidance on the steady-state performance requirements of high-voltage direct current (HVDC) systems. It concerns the steady-state performance of two-terminal HVDC systems utilizing 12-pulse converter units comprised of three-phase bridge (double-way) connections, but it does not cover multi­terminal HVDC transmission systems. Both terminals are assumed to use thyristor valves as the main semiconductor valves and to have power flow capability in both directions. Diode valves are not considered in this document. This edition includes the following significant technical changes with respect to the previous edition:
- Figure 8 and Figure 20 have been updated, a new Figure 18 "LCC/VSC hybrid bipolar system" has been added;
- the HVDC system control objectives have been supplemented;
- additional explanations regarding the HVDC system control structure have been given;
- a new subclause 13.6 on HVDC system protection has been added.

General Information

• Status: Published
• Publication Date: 15-Apr-2020
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 29.200 - Rectifiers. Convertors. Stabilized power supply
• ICS: 29.240.99 - Other equipment related to power transmission and distribution networks
• Technical Committee: SC 22F - Power electronics for electrical transmission and distribution systems
• Drafting Committee: JMT 5 - TC 22/SC 22F/JMT 5
• Current Stage: PPUB - Publication issued
• Start Date: 14-Apr-2020
• Completion Date: 16-Apr-2020

Relations

• Revises: IEC TR 60919-1:2010/AMD1:2013 - Amendment 1 - Performance of high-voltage direct current (HVDC) systems with line-commutated converters - Part 1: Steady-state conditions
• Effective Date: 05-Sep-2023
• Revises: IEC TR 60919-1:2010 - Performance of high-voltage direct current (HVDC) systems with line-commutated converters - Part 1: Steady-state conditions
• Effective Date: 05-Sep-2023
• Revises: IEC TR 60919-1:2010/AMD2:2017 - Amendment 2 - Performance of high-voltage direct current (HVDC) systems with line-commutated converters - Part 1: Steady-state conditions
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC TR 60919-1 ®
Edition 4.0 2020-04
TECHNICAL
REPORT
colour
inside
Performance of high-voltage direct current (HVDC) systems with
line‑commutated converters –
Part 1: Steady-state conditions
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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and withdrawn publications. Also known as the International Electrotechnical Vocabulary

(IEV) online.
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If you wish to give us your feedback on this publication or CISPR.

need further assistance, please contact the Customer Service

Centre: [e-mail].
IEC TR 60919-1 ®
Edition 4.0 2020-04
TECHNICAL
REPORT
colour
inside
Performance of high-voltage direct current (HVDC) systems with

line‑commutated converters –
Part 1: Steady-state conditions

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.200; 29.240.99 ISBN 978-2-8322-8038-6

– 2 – IEC TR 60919-1:2020 © 2020
CONTENTS
FOREWORD . 8
INTRODUCTION . 10
1 Scope . 11
2 Normative references . 12
3 Terms and definitions . 12
4 Types of HVDC systems . 12
4.1 General . 12
4.2 HVDC back-to-back system . 12
4.3 Monopolar HVDC system with earth return . 13
4.4 Monopolar HVDC system with metallic return . 16
4.5 Bipolar earth return HVDC system . 17
4.6 Bipolar HVDC system with metallic return . 20
4.7 Two 12-pulse groups per pole . 21
4.8 Converter transformer arrangements . 24
4.9 DC switching considerations . 25
4.10 Series-capacitor-compensated HVDC systems . 28
4.11 LCC/VSC hybrid bipolar system . 32
5 Environment information . 33
6 Rated power, current and voltage . 36
6.1 Rated power . 36
6.1.1 General . 36
6.1.2 Rated power of an HVDC system with transmission line . 36
6.1.3 Rated power of an HVDC back-to-back system . 36
6.1.4 Direction of power flow . 37
6.2 Rated current . 37
6.3 Rated voltage . 37
7 Overload and equipment capability . 37
7.1 Overload . 37
7.2 Equipment capability . 38
7.2.1 General . 38
7.2.2 Converter valve capability . 38
7.2.3 Capability of oil-cooled transformers and reactors . 39
7.2.4 AC harmonic filter and reactive power compensation equipment
capability . 39
7.2.5 Switchgear and buswork capability . 39
8 Minimum power transfer and no-load stand-by state . 39
8.1 General . 39
8.2 Minimum current . 39
8.3 Reduced direct voltage operation . 40
8.4 No-load stand-by state . 40
8.4.1 General . 40
8.4.2 Converter transformers – No-load stand-by . 40
8.4.3 Converter valves – No-load stand-by . 40
8.4.4 AC filters and reactive compensation – No-load stand-by . 41
8.4.5 DC reactors and DC filters – No-load stand-by . 41

8.4.6 Auxiliary power system – No-load stand-by . 41
8.4.7 Control and protection – No-load stand-by . 41
9 AC system . 41
9.1 General . 41
9.2 AC voltage . 41
9.2.1 Rated AC voltage . 41
9.2.2 Steady-state voltage range . 41
9.2.3 Negative sequence voltage . 42
9.3 Frequency . 42
9.3.1 Rated frequency . 42
9.3.2 Steady-state frequency range . 43
9.3.3 Short-term frequency variation . 43
9.3.4 Frequency variation during emergency . 43
9.4 System impedance at fundamental frequency . 43
9.5 System impedance at harmonic frequencies . 43
9.6 Positive and zero-sequence surge impedance. 43
9.7 Other sources of harmonics . 44
9.8 Subsynchronous torsional interaction (SSTI) . 44
10 Reactive power . 44
10.1 General . 44
10.2 Conventional HVDC systems . 44
10.3 Series capacitor compensated HVDC schemes . 46
10.4 Converter reactive power consumption . 46
10.5 Reactive power balance with the AC system . 46
10.6 Reactive power supply . 46
10.7 Maximum size of switchable VAR banks . 47
11 HVDC transmission line, earth electrode line and earth electrode . 47
11.1 General . 47
11.2 Overhead line(s) . 47
11.2.1 General . 47
11.2.2 Electrical parameters . 47
11.3 Cable line(s) . 48
11.3.1 General . 48
11.3.2 Electrical parameters . 48
11.4 Earth electrode line . 49
11.5 Earth electrode . 49
12 Reliability . 49
12.1 General . 49
12.2 Outage . 49
12.2.1 General . 49
12.2.2 Scheduled outage . 49
12.2.3 Forced outage . 49
12.3 Capacity . 50
12.3.1 General . 50
12.3.2 Maximum continuous capacity P . 50
m
12.3.3 Outage capacity P . 50
o
12.3.4 Outage derating factor (ODF) . 50
12.4 Outage duration terms . 50

– 4 – IEC TR 60919-1:2020 © 2020
12.4.1 Actual outage duration (AOD) . 50
12.4.2 Equivalent outage duration (EOD) . 50
12.4.3 Period hours (PH) .
...

IEC TR 60919-1 ®
Edition 4.0 2020-04
REDLINE VERSION
TECHNICAL
REPORT
colour
inside
Performance of high-voltage direct current (HVDC) systems with
line‑commutated converters –
Part 1: Steady-state conditions

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 Electropedia - www.electropedia.org
The advanced search enables to find IEC publications by a The world's leading online dictionary on electrotechnology,
variety of criteria (reference number, text, technical containing more than 22 000 terminological entries in English
committee,…). It also gives information on projects, replaced and French, with equivalent terms in 16 additional languages.
and withdrawn publications. Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Just Published - webstore.iec.ch/justpublished
Stay up to date on all new IEC publications. Just Published IEC Glossary - std.iec.ch/glossary
details all new publications released. Available online and 67 000 electrotechnical terminology entries in English and
once a month by email. French extracted from the Terms and Definitions clause of
IEC publications issued since 2002. Some entries have been
IEC Customer Service Centre - webstore.iec.ch/csc collected from earlier publications of IEC TC 37, 77, 86 and
If you wish to give us your feedback on this publication or CISPR.

need further assistance, please contact the Customer Service

Centre: [e-mail].
IEC TR 60919-1 ®
Edition 4.0 2020-04
REDLINE VERSION
TECHNICAL
REPORT
colour
inside
Performance of high-voltage direct current (HVDC) systems with

line‑commutated converters –
Part 1: Steady-state conditions

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.200; 29.240.99 ISBN 978-2-8322-8226-7

– 2 – IEC TR 60919-1:2020 RLV © 2020
CONTENTS
FOREWORD . 8
INTRODUCTION . 2
1 Scope . 11
2 Normative references . 12
3 Terms and definitions . 12
4 Types of HVDC systems . 12
4.1 General . 12
4.2 HVDC back-to-back system . 13
4.3 Monopolar HVDC system with earth return HVDC system . 13
4.4 Monopolar HVDC system with metallic return HVDC system . 17
4.5 Bipolar earth return HVDC system . 18
4.6 Bipolar HVDC system with metallic return HVDC system . 21
4.7 Two 12-pulse groups per pole . 22
4.8 Converter transformer arrangements . 25
4.9 DC switching considerations . 26
4.10 Series-capacitor-compensated HVDC systems . 29
4.11 LCC/VSC hybrid bipolar system . 33
5 Environment information . 34
6 Rated power, current and voltage . 37
6.1 Rated power . 37
6.1.1 General . 37
6.1.2 Rated power of an HVDC system with transmission line . 37
6.1.3 Rated power of an HVDC back-to-back system . 37
6.1.4 Direction of power flow . 37
6.2 Rated current . 37
6.3 Rated voltage . 38
7 Overload and equipment capability . 38
7.1 Overload . 38
7.2 Equipment capability . 39
7.2.1 General . 39
7.2.2 Converter valve capability . 39
7.2.3 Capability of oil-cooled transformers and reactors . 39
7.2.4 AC harmonic filter and reactive power compensation equipment
capability . 40
7.2.5 Switchgear and buswork capability . 40
8 Minimum power transfer and no-load stand-by state . 40
8.1 General . 40
8.2 Minimum current . 40
8.3 Reduced direct voltage operation . 40
8.4 No-load stand-by state . 41
8.4.1 General . 41
8.4.2 Converter transformers – No-load stand-by . 41
8.4.3 Converter valves – No-load stand-by . 41
8.4.4 AC filters and reactive compensation – No-load stand-by . 41
8.4.5 DC reactors and DC filters – No-load stand-by . 42

8.4.6 Auxiliary power system – No-load stand-by . 42
8.4.7 Control and protection – No-load stand-by . 42
9 AC system . 42
9.1 General . 42
9.2 AC voltage . 42
9.2.1 Rated AC voltage . 42
9.2.2 Steady-state voltage range . 42
9.2.3 Negative sequence voltage . 43
9.3 Frequency . 43
9.3.1 Rated frequency . 43
9.3.2 Steady-state frequency range . 43
9.3.3 Short-term frequency variation . 43
9.3.4 Frequency variation during emergency . 44
9.4 System impedance at fundamental frequency . 44
9.5 System impedance at harmonic frequencies . 44
9.6 Positive and zero-sequence surge impedance. 44
9.7 Other sources of harmonics . 44
9.8 Subsynchronous torsional interaction (SSTI) . 44
10 Reactive power . 45
10.1 General . 45
10.2 Conventional HVDC systems . 45
10.3 Series capacitor compensated HVDC schemes . 47
10.4 Converter reactive power consumption . 47
10.5 Reactive power balance with the AC system . 47
10.6 Reactive power supply . 47
10.7 Maximum size of switchable VAR banks . 48
11 HVDC transmission line, earth electrode line and earth electrode . 48
11.1 General . 48
11.2 Overhead line(s) . 48
11.2.1 General . 48
11.2.2 Electrical parameters . 48
11.3 Cable line(s) . 49
11.3.1 General . 49
11.3.2 Electrical parameters . 49
11.4 Earth electrode line . 50
11.5 Earth electrode . 50
12 Reliability . 50
12.1 General . 50
12.2 Outage . 50
12.2.1 General . 50
12.2.2 Scheduled outage . 50
12.2.3 Forced outage . 50
12.3 Capacity . 51
12.3.1 General . 51
12.3.2 Maximum continuous capacity P . 51
m
12.3.3 Outage capacity P . 51
o
12.3.4 Outage derating factor (ODF) . 51
12.4 Outage duration terms . 51

– 4 – IEC TR 60919-1:2020 RLV © 2020
12.4.1 Actual outage duration (AOD) . 51
12.4.2 Equivalent outage duration (EOD) . 51
12.4.3 Period hours (PH) .
...