National foreword

This British Standard is the UK implementation of EN IEC 61936‑2:2023. It is identical to IEC 61936‑2:2023. It supersedes PD IEC/TS 61936‑2:2015, which is withdrawn.

The UK participation in its preparation was entrusted to Technical Committee PEL/99, Erection and operation of power installations.

A list of organizations represented on this committee can be obtained on request to its committee manager.

Contractual and legal considerations

This publication has been prepared in good faith, however no representation, warranty, assurance or undertaking (express or implied) is or will be made, and no responsibility or liability is or will be accepted by BSI in relation to the adequacy, accuracy, completeness or reasonableness of this publication. All and any such responsibility and liability is expressly disclaimed to the full extent permitted by the law.

This publication is provided as is, and is to be used at the recipient’s own risk.

The recipient is advised to consider seeking professional guidance with respect to its use of this publication.

This publication is not intended to constitute a contract. Users are responsible for its correct application.

Compliance with a British Standard cannot confer immunity from legal obligations.

This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 November 2023.

FOREWORD

The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International, governmental and non-governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international consensus of opinion on the relevant subjects since each technical committee has representation from all interested IEC National Committees.
IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user.
In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently to the maximum extent possible in their national and regional publications. Any divergence between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any services carried out by independent certification bodies.
All users should ensure that they have the latest edition of this publication.
No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and members of its technical committees and IEC National Committees for any personal injury, property damage or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications.
Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication.
IEC draws attention to the possibility that the implementation of this document may involve the use of (a) patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which may be required to implement this document. However, implementers are cautioned that this may not represent the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC shall not be held responsible for identifying any or all such patent rights.

IEC 61936‑2 has been prepared by IEC technical committee 99: Insulation co-ordination and system engineering and erection of electrical power installations above 1 kV AC and 1,5 kV DC. It is an International Standard.

This first edition cancels and replaces the IEC TS 61936‑2 published in 2015. This edition constitutes a technical revision.

This edition includes the following significant technical changes with respect to the previous edition:

references to IEC 61936‑1 updated to IEC 61936‑1:2021;
alignment with IEC 61936‑1:2021 where required;
the scope has been improved to clarify the application of this document, including an improved definition of a DC installation;
missing and obsolete terms and definitions have been updated including improvement of existing terms;
added new definitions of DC system and converter unit;
added symbols and abbreviated terms;
expansion and improvement of the general requirements, including addition of simplified diagrams showing examples of VSC and LCC DC systems (Figure 1 and Figure 2);
addition of Table 1 which shows where agreements between supplier and user are needed;
clause on electrical requirements has been restructured and improved;
schematic diagrams for various DC system configurations and neutral point locations added (Figure 3);
addition of new content for harmonics and new clauses for electromagnetic compatibility and radio interference;
addition of content specific to DC installations for normal and special conditions;
clause on insulation (Clause 5) has been significantly restructured and rewritten with a change in approach in the clauses on minimum clearances that references relevant parts of IEC 60071;
clause on electrical equipment has been restructured and improved;
clause on DC installations has been restructured and improved;
clause on protection, control and auxiliary systems has been restructured and improved, with content added to the clause on protection systems that is specific to DC installations;
clause on earthing has been restructured and improved;
clause on inspection and testing has been restructured and improved, including addition of references specific to DC installations;
Annex A has been replaced with a new Annex A (informative), where the table of rated insulation levels and minimum clearances in air have been replaced with a table of typical DC voltages and presumed switching and lightning impulse withstand voltages;
tables added to Annex A showing the correlation between presumed switching and lightning impulse withstand voltages and minimum phase-to-earth air clearances;
Annex B has been improved and references updated.

The text of this International Standard is based on the following documents:

Full information on the voting for its approval can be found in the report on voting indicated in the above table.

The language used for the development of this International Standard is English.

This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are described in greater detail at www.iec.ch/publications.

A list of all parts in the IEC 61936 series, published under the general title Power installations exceeding 1 kV AC and 1,5 kV DC, can be found on the IEC website.

Notes concerning particular conditions in certain countries are provided in Annex G of IEC 61936‑1: 2021.

The committee has decided that the contents of this document will remain unchanged until the stability date indicated on the IEC website under webstore.iec.ch in the data related to the specific document. At this date, the document will be

reconfirmed,
withdrawn, or
revised.

IMPORTANT — The "colour inside" logo on the cover page of this document indicates that it contains colours which are considered to be useful for the correct understanding of its contents. Users should therefore print this document using a colour printer.

INTRODUCTION

There are few national laws, standards and internal rules dealing with the matter coming within the scope of this standard, and these practices have been taken as a basis for this work.

This part of IEC 61936 contains the minimum requirements and some additional information which ensures an acceptable reliability of a DC installation with nominal voltages above 1,5 kV DC and its safe operation.

The publication of this document is believed to be a decisive step towards the gradual alignment all over the world of the practices concerning the design and erection of high voltage power installations.

Particular requirements for transmission and distribution installations as well as particular requirements for power generation and industrial installations are included in this document.

The relevant laws or regulations of an authority having jurisdiction take precedence.

This European Standard was approved by CENELEC on 31 October 2023. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and United Kingdom.

European foreword

The text of document 99/413/FDIS, future edition 1 of IEC 61936‑2, prepared by IEC/TC 99 "Insulation co-ordination and system engineering of high voltage electrical power installations above 1,0 kV AC and 1,5 kV DC" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as EN IEC 61936‑2:2023.

The following dates are fixed:

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.

Any feedback and questions on this document should be directed to the users’ national committee. A complete listing of these bodies can be found on the CENELEC website.

Endorsement notice

The text of the International Standard IEC 61936‑2:2023 was approved by CENELEC as a European Standard without any modification.

In the official version, for Bibliography, the following notes have to be added for the standard indicated:

1 Scope

This part of IEC 61936 provides, in a convenient form, requirements for the design and the erection of DC installations in systems with nominal voltages above 1,5 kV DC, so as to provide safety and proper functioning for the use intended.

For the purpose of interpreting this document, a DC installation is considered to be one of the following:

A converter station or DC switching station;
one (or more) DC generating or storage unit(s), such as solar farms or battery storage units, located on a single site, the DC installation includes DC equipment and cables with all associated power electronics, controlgear, switchgear and all electrical auxiliary systems. Connections between DC generating or storage units located on different sites are excluded;
DC installation erected on offshore facilities for the purpose of generation, transmission, distribution and/or storage of electricity; or
DC transition station (between overhead lines and underground cable or between different sections of underground cables).

This International Standard does not apply to the design and erection of any of the following:

overhead and underground lines between separate installations;
electric railways;
mining equipment and installations;
installations on ships according to IEC 60092 series and offshore units according to IEC 61892 series, which are used in the offshore petroleum industry for drilling, processing and storage purposes;
electrostatic equipment (e.g. electrostatic precipitators, spray-painting units);
test sites;
medical equipment, e.g. medical X-ray equipment;
valve hall or converter hall.

This document does not apply to the requirements for carrying out live working on electrical installations.

This document does not apply to the design of factory-built, type-tested thyristor valves, VSC valves and switchgear for which separate IEC standards exist.

2 Normative references

3 Terms, definitions, symbols and abbreviated terms

3.1 Terms and definitions

3.2 Symbols and abbreviated terms

4 Fundamental requirements

4.1 General

4.2 Electrical requirements

4.3 Mechanical requirements

4.4 Climatic and environmental conditions

4.5 Particular requirements

5 Insulation

5.1 General

5.2 Selection of insulation level

5.3 Verification of withstand values

5.4 Minimum clearances of live parts

5.5 Minimum clearances between parts under special conditions

5.6 Tested connection zones

6 Electrical Equipment

6.1 General requirements

6.2 Specific requirements

7 DC Installations

7.1 General

7.2 Outdoor DC installations of open design

7.3 Indoor DC installations of open design

7.4 Installation of prefabricated type-tested switchgear

7.5 Requirements for buildings

7.6 High voltage/low voltage prefabricated substations

7.7 Electrical installations on mast, pole and tower

8 Safety measures

8.1 General

8.2 Protection against direct contact

8.3 Means to protect persons in case of indirect contact

8.4 Means to protect persons working on or near electrical installations

8.5 Protection from danger resulting from arc fault

8.6 Protection against direct lightning strokes

8.7 Protection against fire

8.8 Protection against leakage of insulating liquid and SF₆

8.9 Identification and marking

9 Protection, automation and auxiliary systems

9.1 Protection systems

9.2 Automation systems

9.3 Auxiliary systems

9.4 Basic rules for electromagnetic compatibility of control systems

10 Earthing systems

10.1 General

10.2 Fundamental requirements

10.3 Design of earthing systems

10.4 Construction of earthing systems

10.5 Measurements

10.6 Maintainability

11 Inspection and testing

11.1 General

11.2 Verification of specified performances

11.3 Tests during installation and commissioning

11.4 Trial running

12 Operation and maintenance manual

Bibliography

BS EN IEC 61936-2:2023

Power installations exceeding 1 kV AC and 1,5 kV DC - DC

Current

Published:

30 Nov 2023