IEC TR 63127:2019

Guideline for the system design of HVDC converter stations with line-commutated converters

IEC TR 63127:2019(E) focuses on the system design of converter stations. It is applicable to point-­to-­point and back-to-back HVDC systems based on line-commutated converter (LCC) technology. This document provides guidance and supporting information on the procedure for system design and the technical issues involved in the system design of HVDC transmission projects for both purchaser and potential suppliers. It can be used as the basis for drafting a procurement specification and as a guide during project implementation.

General Information

• Status: Published
• Publication Date: 10-Apr-2024
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 29.240.01 - Power transmission and distribution networks in general
• ICS: 29.240.10 - Substations. Surge arresters
• Technical Committee: TC 115 - High Voltage Direct Current (HVDC) transmission for DC voltages above 100 kV
• Drafting Committee: WG 5 - TC 115/WG 5
• Current Stage: PPUB - Publication issued
• Start Date: 15-Jul-2019
• Completion Date: 26-Jun-2019

Relations

• Amended By: IEC TR 63127:2019/AMD1:2024 - Amendment 1 - Guideline for the system design of HVDC converter stations with line-commutated converters
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC TR 63127 ®
Edition 1.0 2019-06
TECHNICAL
REPORT
Guideline for the system design of HVDC converter stations with line-
commutated converters
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.

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IEC TR 63127 ®
Edition 1.0 2019-06
TECHNICAL
REPORT
Guideline for the system design of HVDC converter stations with line-

commutated converters
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.240.01; 29.240.10 ISBN 978-2-8322-7068-4

– 2 – IEC TR 63127:2019  IEC:2019
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 9
2 Normative references . 9
3 Terms and definitions . 9
4 Symbols . 10
4.1 Letter symbols for variables . 10
4.2 Subscripts . 11
5 Overview of HVDC system design . 11
5.1 General . 11
5.2 Formulation of system design . 13
5.2.1 HVDC system ratings . 13
5.2.2 HVDC system configuration . 13
5.2.3 Reactive power compensation and control . 13
5.2.4 AC/DC interaction and control. 13
5.2.5 Insulation coordination . 14
5.2.6 AC/DC harmonic filtering . 14
5.2.7 Environmental considerations . 14
5.3 System studies and simulations . 14
6 Determination of design conditions and requirements . 16
6.1 Environmental conditions and requirements . 16
6.2 DC transmission line (cable) and earth electrode . 17
6.2.1 Parameters of DC overhead transmission line . 17
6.2.2 Parameters of DC cable . 18
6.2.3 Parameters of electrode line and ground electrode . 18
6.3 AC system conditions. 18
6.3.1 Operating scenarios of AC/DC system . 18
6.3.2 AC system modelling . 18
6.3.3 Relevant AC system protection . 19
6.3.4 Reactive power supply and absorption . 19
6.3.5 Short-circuit current or capacity . 20
6.3.6 AC bus voltage . 20
6.3.7 AC system frequency . 21
6.3.8 Pre-existing harmonic and negative sequence voltage . 21
6.4 Requirements for HVDC systems arising from AC/DC interaction . 22
6.5 AC system equivalents . 23
6.5.1 General . 23
6.5.2 Equivalent for AC/DC system dynamic or transient simulation . 23
6.5.3 Impedance equivalent for AC filter design . 24
6.5.4 System equivalent for low order harmonic resonance study . 25
7 Main circuit design . 26
7.1 Ratings . 26
7.1.1 Rated power . 26
7.1.2 Rated voltage . 27
7.1.3 Rated current . 28
7.2 Configurations . 28

7.2.1 Pole and return path . 28
7.2.2 Converter topology . 29
7.2.3 DC switchyard configuration . 30
7.2.4 Reactive power equipment . 38
7.3 Determination of main circuit parameters . 38
7.3.1 General . 38
7.3.2 Control strategy . 39
7.3.3 Tolerances and errors . 40
7.3.4 Determination of converter transformer impedance . 40
7.3.5 Relative inductive voltage drop (d ) and relative resistive voltage drop
xN
(d ) . 40
rN
7.3.6 Ideal no-load DC voltage . 41
7.3.7 DC voltage and DC current . 41
7.3.8 Rated capacity of converter transformer . 42
7.3.9 Converter transformer taps . 43
7.3.10 Inductance of smoothing reactor . 44
8 Insulation coordination. 44
9 Filter design . 45
9.1 General . 45
9.2 AC filter design . 45
9.3 DC filter design . 45
9.4 Power line carrier (PLC) filters . 46
9.5 Radio frequency interference (RFI) . 46
10 Reactive power compensation and control . 47
10.1 General . 47
10.2 Reactive power consumption . 47
10.2.1 Reactive power consumption calculation . 47
10.2.2 Maximum reactive power consumption . 48
10.2.3 Minimum reactive power consumption . 48
10.3 Determination of reactive power equipment capacity . 48
10.3.1 General . 48
10.3.2 Capacity of reactive power supply equipment . 48
10.3.3 Capacity of reactive power absorption equipment . 48
10.3.4 Sizing of reactive power sub-bank . 49
10.3.5 Sizing of reactive power bank . 49
10.4 Reactive power control . 49
10.4.1 General . 49
10.4.2 Reactive power exchange control/voltage control . 50
10.4.3 Voltage limitation . 50
10.5 Temporary overvoltage control . 51
11 Basic parameters of main equipment . 51
11.1 General . 51
11.2 Converter valves . 51
11.2.1 General . 51
11.2.2 Valve hall environment . 51
11.2.3 Current rating . 52
11.2.4 Voltage rating . 52
11.2.5 Losses of converter valves . 53
11.2.6 Testing requirements . 53

– 4 – IEC TR 63127:2019  IEC:2019
11.3 Converter transformers . 53
11.3.1 General . 53
11.3.2 Current rating .
...

IEC TR 63127 ®
Edition 1.1 2024-04
CONSOLIDATED VERSION
TECHNICAL
REPORT
colour
inside
Guideline for the system design of HVDC converter stations with line-
commutated converters
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, graphical symbols and the glossary.
committee, …). It also gives information on projects, replaced With a subscription you will always have access to up to date
and withdrawn publications. content tailored to your needs.

IEC Just Published - webstore.iec.ch/justpublished
Electropedia - www.electropedia.org
Stay up to date on all new IEC publications. Just Published
The world's leading online dictionary on electrotechnology,
details all new publications released. Available online and once
containing more than 22 500 terminological entries in English
a month by email.
and French, with equivalent terms in 25 additional languages.

Also known as the International Electrotechnical Vocabulary
IEC Customer Service Centre - webstore.iec.ch/csc
(IEV) online.
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 63127 ®
Edition 1.1 2024-04
CONSOLIDATED VERSION
TECHNICAL
REPORT
colour
inside
Guideline for the system design of HVDC converter stations with line-
commutated converters
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.240.01; 29.240.10 ISBN 978-2-8322-8767-5
REDLINE VERSION – 2 – IEC TR 63127:2019+AMD1:2024 CSV
 IEC 2024
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 9
2 Normative references . 9
3 Terms and definitions . 9
4 Symbols . 10
4.1 Letter symbols for variables . 10
4.2 Subscripts . 11
5 Overview of HVDC system design . 11
5.1 General . 11
5.2 Formulation of system design . 13
5.2.1 HVDC system ratings . 13
5.2.2 HVDC system configuration . 13
5.2.3 Reactive power compensation and control . 13
5.2.4 AC/DC interaction and control. 13
5.2.5 Insulation coordination . 14
5.2.6 AC/DC harmonic filtering . 14
5.2.7 Environmental considerations . 14
5.3 System studies and simulations . 14
6 Determination of design conditions and requirements . 16
6.1 Environmental conditions and requirements . 16
6.2 DC transmission line (cable) and earth electrode . 17
6.2.1 Parameters of DC overhead transmission line . 17
6.2.2 Parameters of DC cable . 18
6.2.3 Parameters of electrode line and ground electrode . 18
6.3 AC system conditions. 18
6.3.1 Operating scenarios of AC/DC system . 18
6.3.2 AC system modelling . 18
6.3.3 Relevant AC system protection . 19
6.3.4 Reactive power supply and absorption . 19
6.3.5 Short-circuit current or capacity . 20
6.3.6 AC bus voltage . 21
6.3.7 AC system frequency . 21
6.3.8 Pre-existing harmonic and negative sequence voltage . 22
6.4 Requirements for HVDC systems arising from AC/DC interaction . 22
6.5 AC system equivalents . 23
6.5.1 General . 23
6.5.2 Equivalent for AC/DC system dynamic or transient simulation . 23
6.5.3 Impedance equivalent for AC filter design . 24
6.5.4 System equivalent for low order harmonic resonance study . 26
7 Main circuit design . 26
7.1 Ratings . 26
7.1.1 Rated power . 26
7.1.2 Rated voltage . 27
7.1.3 Rated current . 28
7.2 Configurations . 28

 IEC 2024
7.2.1 Pole and return path . 28
7.2.2 Converter topology . 29
7.2.3 DC switchyard configuration . 30
7.2.4 Reactive power equipment . 38
7.3 Determination of main circuit parameters . 38
7.3.1 General . 38
7.3.2 Control strategy . 39
7.3.3 Tolerances and errors . 40
7.3.4 Determination of converter transformer impedance . 40
7.3.5 Relative inductive voltage drop (d ) and relative resistive voltage drop
xN
(d ) . 40
rN
7.3.6 Ideal no-load DC voltage . 41
7.3.7 DC voltage and DC current . 41
7.3.8 Rated capacity of converter transformer . 42
7.3.9 Converter transformer taps . 43
7.3.10 Inductance of smoothing reactor . 44
8 Insulation coordination. 44
9 Filter design . 45
9.1 General . 45
9.2 AC filter design . 45
9.3 DC filter design . 45
9.4 Power line carrier (PLC) filters . 46
9.5 Radio frequency interference (RFI) . 46
10 Reactive power compensation and control . 47
10.1 General . 47
10.2 Reactive power consumption . 47
10.2.1 Reactive power consumption calculation . 47
10.2.2 Maximum reactive power consumption . 48
10.2.3 Minimum reactive power consumption . 48
10.3 Determination of reactive power equipment capacity . 48
10.3.1 General . 48
10.3.2 Capacity of reactive power supply equipment . 48
10.3.3 Capacity of reactive power absorption equipment . 48
10.3.4 Sizing of reactive power sub-bank . 49
10.3.5 Sizing of reactive power bank . 49
10.4 Reactive power control . 49
10.4.1 General . 49
10.4.2 Reactive power exchange control/voltage control . 50
10.4.3 Voltage limitation . 50
10.5 Temporary overvoltage control . 51
11 Basic parameters of main equipment . 51
11.1 General . 51
11.2 Converter valves . 51
11.2.1 General . 51
11.2.2 Valve hall environment . 51
11.2.3 Current rating . 52
11.2.4 Voltage rating . 52
11.2.5 Losses of converter valves . 53
11.2.6 Testing requirements . 53

REDLINE VERSION – 4 – IEC TR 63127:2019+AMD1:2024 CSV
 IEC 2024
11.3 Converter transformers . 53
11.3.1 General . 53
11.3.2 Current rating .
...