EN IEC 60071-12:2022

Insulation co-ordination - Part 12: Application guidelines for LCC HVDC converter stations

IEC 60071-12:2022 applies guidelines on the procedures for insulation co-ordination of line commutated converter (LCC) stations for high-voltage direct current (HVDC) project, whose aim is evaluating the overvoltage stresses on the converter station equipment subjected to combined DC, AC power frequency, harmonic and impulse voltages, and determining the specified withstand voltages for equipment. This document deals only with metal-oxide surge arresters, without gaps, which are used in modern HVDC converter stations. The criteria for determining the protective levels of series and/or parallel combinations of surge arresters used to ensure optimal protection are also presented. Typical arrester protection schemes and stresses of arresters are presented. Annex A contains examples of insulation co-ordination for LCC HVDC converters which support the concepts described in the main text, and the basic analytical techniques used.

Isolationskoordination - Teil 12: Anwendungsrichtlinien für HGÜ-Stromrichterstationen mit Stromzwischenkreis-Konverter (LCC)

Coordination de l’isolement - Partie 12: Lignes directrices en matière d’application pour stations de conversion à courant continu haute tension (CCHT) équipées de convertisseurs commutés par le réseau (LCC)

L'IEC 60071-12:2022 applique des lignes directrices concernant les procédures de coordination de l’isolement des stations de conversion équipées de convertisseurs commutés par le réseau (LCC) pour des installations à courant continu haute tension (CCHT), dont l’objectif est d’évaluer les contraintes de surtension exercées sur le matériel soumis à des tensions combinées de fréquence, d'harmoniques et d'impulsions de courant continu et alternatif et de déterminer les tensions de tenue spécifiées pour le matériel. Le présent document traite seulement des parafoudres à oxyde métallique, sans éclateurs, qui sont utilisés dans les stations de conversion à CCHT modernes. Les critères de détermination des niveaux de protection des combinaisons de montages en série et/ou en parallèle des parafoudres utilisés pour assurer une protection optimale sont également présentés, de même que les schémas types de la protection par parafoudre et les contraintes des parafoudres. L’Annexe A comporte des exemples de coordination de l’isolement pour les convertisseurs CCHT LCC qui prennent en charge les concepts décrits dans le corps du texte, ainsi que les techniques d’analyse de base employées.

Koordinacija izolacije - 12. del: Smernice za uporabo LCC HVDC (visokonapetostnih enosmernih) pretvorniških postaj

Ta del standarda IEC 60071 podaja smernice za postopke koordinacije izolacije pretvorniških postaj z linijskim komutiranjem (LCC) za projekt visokonapetostnega enosmernega toka (HVDC), katerega cilj je ovrednotenje prenapetostnih obremenitev opreme pretvorniških postaj, ki je izpostavljena kombinirani enosmerni/izmenični močnostni frekvenci ter harmonskim in impulznim napetostim, ter določitev navedenih vzdržnih napetosti za opremo. V tem dokumentu so obravnavani le prenapetostni odvodniki iz kovinskega oksida brez iskrišč, ki se uporabljajo v sodobnih visokonapetostnih enosmernih pretvorniških postajah. Predstavljena so tudi merila za določanje zaščitnih ravni prenapetostnih odvodnikov v serijah in/ali vzporednih kombinacijah, ki se uporabljajo za zagotavljanje optimalne zaščite. Predstavljene so tipične sheme zaščite in obremenitve odvodnikov. Dodatek A vsebuje primere koordinacije izolacije za visokonapetostne enosmerne pretvornike z linijskim komutiranjem, ki utemeljujejo koncepte, opisane v glavnem besedilu, ter navaja osnovne uporabljene analitske tehnike.

General Information

• Status: Published
• Publication Date: 24-Nov-2022
• ICS: 29.080.30 - Insulation systems
• Technical Committee: CLC/TC 99X - Power installations exceeding 1 kV a.c. (1,5 kV d.c.)
• Drafting Committee: IEC/TC 99 - IEC_TC_99
• Current Stage: 6060 - Document made available - Publishing
• Start Date: 25-Nov-2022
• Completion Date: 25-Nov-2022
• Ref Project: SIST EN IEC 60071-12:2023 - Insulation co-ordination - Part 12: Application guidelines for LCC HVDC converter stations

Relations

• Splited From: EN 60071-5:2015 - Insulation co-ordination - Part 5: Procedures for high-voltage direct current (HVDC) converter stations
• Effective Date: 01-Nov-2022

Standards Content (Sample)

SLOVENSKI STANDARD
01-januar-2023
Nadomešča:
SIST EN 60071-5:2015
Koordinacija izolacije - 12. del: Smernice za uporabo LCC HVDC
(visokonapetostnih enosmernih) pretvorniških postaj
Insulation co-ordination - Part 12: Application guidelines for LCC HVDC converter
stations
Ta slovenski standard je istoveten z: EN IEC 60071-12:2022
ICS:
29.080.30 Izolacijski sistemi Insulation systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 60071-12

NORME EUROPÉENNE
EUROPÄISCHE NORM November 2022
ICS 29.080.30
Supersedes EN 60071-5:2015 (partially)
English Version
Insulation co-ordination - Part 12: Application guidelines for LCC
HVDC converter stations
(IEC 60071-12:2022)
Coordination de l'isolement - Partie 12: Lignes directrices Isolationskoordination für HVDC Systeme - Teil 12:
en matière d'application pour stations de conversion à Anwendungsrichtlinien für Stromrichterstationen mit
courant continu haute tension (CCHT) équipées de Stromzwischenkreis-Konverter (LCC)
convertisseurs commutés par le réseau (LCC) (IEC 60071-12:2022)
(IEC 60071-12:2022)
This European Standard was approved by CENELEC on 2022-11-18. 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, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2022 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 60071-12:2022 E

European foreword
The text of document 99/368/FDIS, future edition 1 of IEC 60071-12, 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 60071-12:2022.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2023-08-18
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2025-11-18
document have to be withdrawn
This document partially supersedes EN 60071-5:2015 and all of its amendments and corrigenda (if
any).
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 60071-12:2022 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:
IEC 60060-1 NOTE Harmonized as EN 60060-1
IEC 60071-1:2019 NOTE Harmonized as EN IEC 60071-1:2019 (not modified)
IEC 60071-2:2018 NOTE Harmonized as EN IEC 60071-2:2018 (not modified)
IEC 60071-5:2014 NOTE Harmonized as EN 60071-5:2015 (not modified)
IEC 60099-5:2018 NOTE Harmonized as EN IEC 60099-5:2018 (not modified)
IEC 60099-9:2014 NOTE Harmonized as EN 60099-9:2014 (not modified)
IEC 60505:2011 NOTE Harmonized as EN 60505:2011 (not modified)
IEC 60700-1:2015/AMD1:2021 NOTE Harmonized as EN 60700-1:2015/A1:2021 (not modified)
IEC 60721-3-0:2020 NOTE Harmonized as EN IEC 60721-3-0:2020 (not modified)
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
NOTE 1  Where an International Publication has been modified by common modifications, indicated by (mod),
the relevant EN/HD applies.
NOTE 2  Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cenelec.eu.
Publication Year Title EN/HD Year
1 2
IEC 60071-11 - Insulation co-ordination - Part 11 - EN IEC 60071-11 -
Definitions, principles and rules for HVDC
system
IEC 60099-4 - Surge arresters - Part 4: Metal-oxide EN 60099-4 -
surge arresters without gaps for a.c.
systems
IEC 60633 - High-voltage direct current (HVDC) EN IEC 60633 -
transmission - Vocabulary
Under preparation. Stage at the time of publication: IEC/CFDIS 60071-11:2022.
Under preparation. Stage at the time of publication: FprEN IEC 60071-11:2022.
IEC 60071-12 ®
Edition 1.0 2022-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Insulation co-ordination –
Part 12: Application guidelines for LCC HVDC converter stations

Coordination de l’isolement –
Partie 12: Lignes directrices en matière d’application pour stations de

conversion à courant continu haute tension (CCHT) équipées de convertisseurs

commutés par le réseau (LCC)
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.080.30 ISBN 978-2-8322-5845-3

– 2 – IEC 60071-12:2022 © IEC 2022
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms, definitions, symbols and abbreviated terms . 7
3.1 Terms and definition . 7
3.2 Symbols and abbreviated terms . 8
3.2.1 General . 8
3.2.2 Subscripts . 8
3.2.3 Letter symbols . 8
3.2.4 Abbreviated terms . 9
4 Typical LCC HVDC converter station schemes . 9
5 Voltages and overvoltages in service . 12
5.1 Continuous operating voltages at various locations in the converter station . 12
5.2 Peak continuous operating voltage (PCOV) and crest continuous operating
voltage (CCOV) . 16
5.3 Sources and types of overvoItages . 18
5.4 Temporary overvoltage . 18
5.4.1 General . 18
5.4.2 Temporary overvoltage on the AC side . 18
5.4.3 Temporary overvoltages on the DC side . 19
5.5 Slow-front overvoltages . 19
5.5.1 General . 19
5.5.2 Slow-front overvoltages on the AC side . 19
5.5.3 Slow-front overvoltages on the DC side . 20
5.6 Fast-front, very-fast-front and steep-front overvoltages . 20
6 Arrester characteristics and stresses . 21
6.1 Arrester characteristics . 21
6.2 Arrester specification . 22
6.3 Arrester stresses. 23
6.3.1 General . 23
6.3.2 AC bus arrester (A) . 24
6.3.3 AC filter arrester (FA) . 24
6.3.4 Transformer valve winding arresters (T). 25
6.3.5 Valve arrester (V) . 25
6.3.6 Bridge arrester (B) . 28
6.3.7 Converter unit arrester (C) . 28
6.3.8 Mid-point DC bus arrester (M) . 29
6.3.9 Converter unit DC bus arrester (CB) . 29
6.3.10 DC bus and DC line/cable arrester (DB and DL/DC) . 30
6.3.11 Neutral bus arrester (E, EL, EM in Figure 3, EB, E1, EL, EM in Figure 1) . 30
6.3.12 DC reactor arrester (DR) . 31
6.3.13 DC filter arrester (FD) . 32
6.3.14 Earth electrode station arrester. 32
6.4 Protection strategy . 32
6.4.1 General . 32
6.4.2 Insulation directly protected by a single arrester . 32
6.4.3 Insulation protected by more than one arrester in series . 32

IEC 60071-12:2022 © IEC 2022 – 3 –
6.4.4 Valve side neutral point of transformers . 33
6.4.5 Insulation between phase conductors of the converter transformer . 33
6.4.6 Summary of protection strategy . 33
6.5 Summary of events and stresses . 36
7 Design procedure of insulation co-ordination . 37
7.1 General . 37
7.2 Arrester requirements . 38
7.3 Representative overvoltages (U ) . 38
rp
7.4 Determination of the co-ordination withstand voltages (U ) . 40
cw
7.5 Determination of the required withstand voltages (U ) . 40
rw
7.6 Determination of the specified withstand voltage (U ) . 40
w
8 Study tools and system modelling . 40
8.1 General . 40
8.2 Study approach and tooIs . 40
8.3 System details .
...