SIST EN 60071-5:2015

SLOVENSKI STANDARD
SIST EN 60071-5:2015
01-september-2015
Koordinacija izolacije - 5. del: Postopki za visokonapetostne enosmerne
presmerniške postaje
Insulation co-ordination - Part 5: Procedures for high-voltage direct current (HVDC)
converter stations
Isolationskoordination - Teil 5: Verfahren für Hochspannungs-Gleichstrom-
Stromrichterstationen (HGÜ-Stromrichterstationen)
Coordination de l’isolement - Partie 5: Procédures pour les stations de conversion à
courant continu haute tension (CCHT)
Ta slovenski standard je istoveten z: EN 60071-5:2015
ICS:
29.080.01 (OHNWULþQDL]RODFLMDQD Electrical insulation in
VSORãQR general
SIST EN 60071-5:2015 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 60071-5:2015

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SIST EN 60071-5:2015


EUROPEAN STANDARD EN 60071-5

NORME EUROPÉENNE

EUROPÄISCHE NORM
January 2015
ICS 29.080.30

English Version
Insulation co-ordination -
Part 5: Procedures for high-voltage direct current (HVDC)
converter stations
(IEC 60071-5:2014)
Coordination de l'isolement -  Isolationskoordination -
Partie 5: Procédures pour les stations de conversion à Teil 5: Verfahren für Hochspannungs-Gleichstrom-
courant continu haute tension (CCHT) Stromrichterstationen (HGÜ-Stromrichterstationen)
(IEC 60071-5:2014) (IEC 60071-5:2014)
This European Standard was approved by CENELEC on 2014-11-28. 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.


European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2015 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
 Ref. No. EN 60071-5:2015 E

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SIST EN 60071-5:2015
EN 60071-5:2015 - 2 -
Foreword
The text of document 28/218/FDIS, future edition 1 of IEC 60071-5, prepared by IEC/TC 28 "Insulation
co-ordination" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
EN 60071-5:2015.

The following dates are fixed:
(dop) 2015-08-28
• latest date by which the document has to be
implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2017-11-28
standards conflicting with the
document have to be withdrawn

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

Endorsement notice
The text of the International Standard IEC 60071-5:2014 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 standards indicated:

1)
IEC 60099-5:1996 NOTE Harmonized as EN 60099-5:1996 (modified).
IEC 60505:2011 NOTE Harmonized as EN 60505:2011 (not modified).
IEC 60721-3-0:1984 NOTE Harmonized as EN 60721-3-0:1993 (not modified).
IEC/TR 60919-2:2008 NOTE Harmonized as CLC/TR 60919-2:2010 (not modified).
IEC 60700-1:1998 NOTE Harmonized as EN 60700-1:1998 (not modified).
IEC 60700-1:1998/A1:2003 NOTE Harmonized as EN 60700-1:1998/A1:2003 (not modified).
IEC 60700-1:1998/A2:2008 NOTE Harmonized as EN 60700-1:1998/A2:2008 (not modified).

1)
Superseded by EN 60099-5:2013 (IEC 60099-5:2013) - DOW = 2016-06-26.

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SIST EN 60071-5:2015
- 3 - EN 60071-5:2015
Annex ZA
(normative)

Normative references to international publications
with their corresponding European publications

The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.

NOTE 1 When 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

IEC 60060-1 -  High-voltage test techniques - EN 60060-1 -
Part 1: General definitions and test
requirements
IEC 60071-1 2006 Insulation co-ordination - EN 60071-1 2006
Part 1: Definitions, principles and rules
IEC 60071-2 1996 Insulation co-ordination - EN 60071-2 1997
Part 2: Application guide
IEC 60099-4 (mod) 2004 Surge arresters - EN 60099-4 2004
Part 4: Metal-oxide surge arresters
without gaps for a.c. systems
IEC 60633 -  Terminology for high-voltage EN 60633 -
direct current (HVDC) transmission
IEC/TS 60815-1 2008 Selection and dimensioning
of high-voltage insulators intended
for use in polluted conditions -
Part 1: Definitions, information and general
principles
IEC/TS 60815-2 2008 Selection and dimensioning of high-voltage - -
insulators intended for use in polluted
conditions -
Part 2: Ceramic and glass insulators for
a.c. systems
IEC/TS 60815-3 2008 Selection and dimensioning of high-voltage - -
insulators intended for use in polluted
conditions -
Part 3: Polymer insulators for a.c. systems

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SIST EN 60071-5:2015

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SIST EN 60071-5:2015




IEC 60071-5

®


Edition 1.0 2014-10




INTERNATIONAL



STANDARD




NORME



INTERNATIONALE
colour

inside










Insulation co-ordination –

Part 5: Procedures for high-voltage direct current (HVDC) converter stations




Coordination de l’isolement –

Partie 5: Procédures pour les stations de conversion à courant continu haute

tension (CCHT)















INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE

PRICE CODE
INTERNATIONALE

CODE PRIX XD


ICS 29.080.30 ISBN 978-2-8322-1887-7



Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

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SIST EN 60071-5:2015
– 2 – IEC 60071-5:2014 © IEC 2014

CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 General . 9
1.1 Scope . 9
1.2 Additional background . 9
2 Normative references . 10
3 Terms and definitions. 10
4 Symbols and abbreviations . 16
4.1 General . 16
4.2 Subscripts . 16
4.3 Letter symbols . 16
4.4 Abbreviations . 17
5 Typical HVDC converter station schemes . 17
6 Principles of insulation co-ordination . 21
6.1 General . 21
6.2 Essential differences between a.c. and d.c. systems . 21
6.3 Insulation co-ordination procedure . 21
6.4 Comparison of withstand voltage selection in a.c. and d.c. systems . 22
7 Voltages and overvoltages in service . 24
7.1 Continuous operating voltages at various locations in the converter station . 24
7.2 Peak continuous operating voltage (PCOV) and crest continuous operating
voltage (CCOV) . 28
7.3 Sources and types of overvoltages . 30
7.4 Temporary overvoltages . 31
7.4.1 General . 31
7.4.2 Temporary overvoltages on the a.c. side . 31
7.4.3 Temporary overvoltages on the d.c. side . 31
7.5 Slow-front overvoltages . 31
7.5.1 General . 31
7.5.2 Slow-front overvoltages on the a.c. side . 31
7.5.3 Slow-front overvoltages on the d.c. side . 32
7.6 Fast-front, very-fast-front and steep-front overvoltages . 33
8 Arrester characteristics and stresses. 34
8.1 Arrester characteristics . 34
8.2 Arrester specification. 35
8.3 Arrester stresses . 35
8.3.1 General . 35
8.3.2 AC bus arrester (A) . 36
8.3.3 AC filter arrester (FA) . 37
8.3.4 Transformer valve winding arresters (T) . 37
8.3.5 Valve arrester (V) . 37
8.3.6 Bridge arrester (B) . 40
8.3.7 Converter unit arrester (C) . 41
8.3.8 Mid-point d.c. bus arrester (M) . 41
8.3.9 Converter unit d.c. bus arrester (CB) . 42
8.3.10 DC bus and d.c. line/cable arrester (DB and DL/DC) . 42

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SIST EN 60071-5:2015
IEC 60071-5:2014 © IEC 2014 – 3 –
8.3.11 Neutral bus arrester (E, EL, EM in Figure 3, EB, E1, EL, EM in Figure 1) . 42
8.3.12 DC reactor arrester (DR) . 43
8.3.13 DC filter arrester (FD) . 44
8.3.14 Earth electrode station arrester . 44
8.4 Protection strategy . 44
8.4.1 General . 44
8.4.2 Insulation directly protected by a single arrester . 44
8.4.3 Insulation protected by more than one arrester in series . 45
8.4.4 Valve side neutral point of transformers . 45
8.4.5 Insulation between phase conductors of the converter transformer . 45
8.4.6 Summary of protection strategy . 45
8.5 Summary of events and stresses . 47
9 Design procedure of insulation co-ordination . 49
9.1 General . 49
9.2 Arrester requirements. 49
9.3 Characteristics of insulation. 51
9.4 Representative overvoltages (U ) . 51
rp
9.5 Determination of the co-ordination withstand voltages (U ) . 52
cw
9.6 Determination of the required withstand voltages (U ) . 52
rw
9.7 Determination of the specified withstand voltage (U ) . 54
w
10 Study tools and system modelling . 54
10.1 General . 54
10.2 Study approach and tools . 54
10.3 System details . 55
10.3.1 Modelling and system representation . 55
10.3.2 AC network and a.c. side of the HVDC converter station . 57
10.3.3 DC overhead line/cable and earth electrode line details . 58
10.3.4 DC side of an HVDC converter station details . 58
11 Creepage distances . 59
11.1 General . 59
11.2 Base voltage for creepage distance . 59
11.3 Creepage distance for outdoor insulation under d.c. voltage . 59
11.4 Creepage distance for indoor insulation under d.c. or mixed voltage . 60
11.5 Creepage distance of a.c. insulators . 60
12 Clearances in air . 60
Annex A (informative) Example of insulation co-ordination for conventional HVDC
converters . 62
A.1 General . 62
A.2 Arrester protective scheme . 62
A.3 Arrester stresses, protection and insulation levels. 62
A.3.1 General . 62
A.3.2 Slow-front overvoltages transferred from the a.c. side . 63
A.3.3 Earth fault between valve and upper bridge transformer bushing . 63
A.4 Transformer valve side withstand voltages . 66
A.4.1 Phase-to-phase . 66
A.4.2 Upper bridge transformer phase-to-earth (star). 67
A.4.3 Lower bridge transformer phase-to-earth (delta) . 67
A.5 Air-insulated smoothing reactors withstand voltages . 67
A.5.1 Terminal-to-terminal slow-front overvoltages . 67

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SIST EN 60071-5:2015
– 4 – IEC 60071-5:2014 © IEC 2014

A.5.2 Terminal-to-earth . 68
A.6 Results . 68
Annex B (informative) Example of insulation co-ordination for capacitor commutated
converters (CCC) and controlled series capacitor converters (CSCC) . 72
B.1 General . 72
B.2 Arrester protective scheme . 72
B.3 Arrester stresses, protection and insulation levels. 72
B.3.1 General . 72
B.3.2 Transferred slow-front overvoltages from the a.c. side . 73
B.3.3 Earth fault between valve and upper bridge transformer bushing . 74
B.4 Transformer valve side withstand voltages . 77
B.4.1 Phase-to-phase . 77
B.4.2 Upper bridge transformer phase-to-earth (star). 77
B.4.3 Lower bridge transformer phase-to-earth (delta) . 77
B.5 Air-insulated smoothing reactors withstand voltages . 78
B.5.1 Slow-front terminal-to-terminal overvoltages . 78
B.5.2 Terminal-to-earth . 78
B.6 Results . 79
Annex C (informative) Considerations for insulation co-ordination of some special
converter configurations . 87
C.1 Procedure for insulation co-ordination of back-to-back type of HVDC links . 87
C.2 Procedure for insulation co-ordination of parallel valve groups . 87
C.2.1 General . 87
C.2.2 AC bus arrester (A) . 88
C.2.3 AC filter arrester (FA) . 88
C.2.4 Valve arrester (V) . 88
C.2.5 Bridge arrester (B) and converter unit arrester (C) . 88
C.2.6 Mid-point arrester (M) . 88
C.2.7 Converter unit d.c. bus arrester (CB) . 88
C.2.8 DC bus and d.c. line/cable arrester (DB and DL) . 89
C.2.9 Neutral bus arrester (E) . 89
C.2.10 DC reactor arrester (DR) . 89
C.2.11 DC filter arrester (FD) . 89
C.2.12 New converter stations with parallel valve groups . 89
C.3 Procedure for insulation co-ordination of upgrading existing systems with
series-connected valve groups . 89
C.3.1 General . 89
C.3.2 AC bus arrester (A) . 90
C.3.3 AC filter arrester (FA) . 90
C.3.4 Valve arrester (V) . 90
C.3.5 Bridge arrester (B) and converter unit arrester (C) . 90
C.3.6 Mid-point arrester (M) . 90
C.3.7 Converter unit d.c. bus arrester (CB), d.c. bus and d.c. line/cable
arrester (DB and DL) . 91
C.3.8 Neutral bus arrester (E) . 91
C.3.9 DC reactor arrester (DR) . 91
C.3.10 DC filter arrester (FD) . 91
C.4 Overvoltages in the a.c. network due to closely coupled HVDC links . 91
C.5 Effect of gas-insulated switchgear on insulation co-ordination of HVDC
converter stations . 92

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SIST EN 60071-5:2015
IEC 60071-5:2014 © IEC 2014 – 5 –
Annex D (informative) Typical arrester characteristics . 93
Bibliography . 94

Figure 1 – Possible arrester locations in a pole with two 12-pulse converters in series . 19
Figure 2 – Possible arrester locations for a back-to-back converter station . 20
Figure 3 – HVDC converter station with one 12-pulse converter bridge per pole . 25
Figure 4 – Continuous operating voltages at various locations (location identification
according to Figure 3) . 27
Figure 5 – Operating voltage of a valve arrester (V), rectifier operation . 29
Figure 6 – Operating voltage of a mid-point arrester (M), rectifier operation . 29
Figure 7 – Operating voltage of a converter bus arrester (CB), rectifier operation . 30
Figure 8 – One pole of an HVDC converter station . 57
Figure A.1 – AC and d.c. arresters . 69
Figure A.2 – Valve arrester stresses for slow-front overvoltages from a.c. side . 69
Figure A.3 – Arrester V2 stress for slow-front overvoltage from a.c. side . 70
Figure A.4 – Valve arrester stresses for earth fault between valve and upper bridge
transformer bushing . 70
Figure A.5 – Arrester V1 stress for earth fault between valve and upper bridge
transformer bushing . 71
Figure B.1 – AC and d.c. arresters for CCC and CSCC converters . 80
Figure B.2 – Valve arrester stresses for slow-front overvoltages from a.c. side . 81
Figure B.3 – Arrester V2 stress for slow-front overvoltage from a.c. side . 82
Figure B.4 – Valve arrester stresses for earth fault between valve and upper bridge
transformer bushing . 84
Figure B.5 – Arrester V1 stress for earth fault between valve and upper bridge
transformer bushing . 85
Figure B.6 – Stresses on capacitor arresters C and C during earth fault between
cc sc
valve and upper bridge transformer bushing . 86
Figure C.1 – Expanded HVDC converter with parallel valve groups . 88
Figure C.2 – Upgraded HVDC converter with series valve group . 90
Figure D.1 – Typical arrester V-I characteristics . 93

Table 1 – Classes and shapes of overvoltages, standard voltage shapes and standard
withstand voltage tests . 11
Table 2 – Symbol description. 20
Table 3 – Comparison of the selection of withstand voltages for a.c. equipment with
that for HVDC converter station equipment . 23
Table 4 – Arrester protection on the d.c. side: Single 12-pulse converter (Figure 3) . 46
Table 5 – Arrester protection on the d.c. side: Two 12-pulse converters (Figure 1) . 46
Table 6 – Events stressing arresters: Single 12-pulse converter (Figure 3). 48
Table 7 – Types of arrester stresses for different events: Single 12-pulse converter
(Figure 3) . 48
Table 8 – Arrester requirements . 50
Table 9 – Representative overvoltages and required withstand voltages. 51
Table 10 – Indicative values of ratios of required impulse withstand voltage to impulse

protective level . 54
Table 11 – Origin of overvoltages and associated frequency ranges. 56

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SIST EN 60071-5:2015
– 6 – IEC 60071-5:
...