IEC 62501:2009

IEC 62501 ®
Edition 1.1 2014-08
CONSOLIDATED
VERSION
VERSION
CONSOLIDÉE
colour
inside
Voltage sourced converter (VSC) valves for high-voltage direct current (HVDC)
power transmission – Electrical testing

Valves à convertisseur de source de tension (VSC) pour le transport d’énergie
en courant continu à haute tension (CCHT) – Essais électriques

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.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite
ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie

et les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des

questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.

IEC Central Office Tel.: +41 22 919 02 11
3, rue de Varembé Fax: +41 22 919 03 00
CH-1211 Geneva 20 info@iec.ch
Switzerland www.iec.ch
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 corrigenda or an amendment might have been published.

IEC Catalogue - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
The stand-alone application for consulting the entire The world's leading online dictionary of electronic and
bibliographical information on IEC International Standards, electrical terms containing more than 30 000 terms and
Technical Specifications, Technical Reports and other definitions in English and French, with equivalent terms in 14
documents. Available for PC, Mac OS, Android Tablets and additional languages. Also known as the International
iPad. Electrotechnical Vocabulary (IEV) online.

IEC publications search - www.iec.ch/searchpub IEC Glossary - std.iec.ch/glossary
The advanced search enables to find IEC publications by a More than 55 000 electrotechnical terminology entries in
variety of criteria (reference number, text, technical English and French extracted from the Terms and Definitions
committee,…). It also gives information on projects, replaced clause of IEC publications issued since 2002. Some entries
and withdrawn publications. have been collected from earlier publications of IEC TC 37,

77, 86 and CISPR.
IEC Just Published - webstore.iec.ch/justpublished
Stay up to date on all new IEC publications. Just Published IEC Customer Service Centre - webstore.iec.ch/csc
details all new publications released. Available online and If you wish to give us your feedback on this publication or
also once a month by email. need further assistance, please contact the Customer Service
Centre: csc@iec.ch.
A propos de l'IEC
La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des
Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications IEC
Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la
plus récente, un corrigendum ou amendement peut avoir été publié.

Catalogue IEC - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
Application autonome pour consulter tous les renseignements
Le premier dictionnaire en ligne de termes électroniques et
bibliographiques sur les Normes internationales,
électriques. Il contient plus de 30 000 termes et définitions en
Spécifications techniques, Rapports techniques et autres
anglais et en français, ainsi que les termes équivalents dans
documents de l'IEC. Disponible pour PC, Mac OS, tablettes
14 langues additionnelles. Egalement appelé Vocabulaire
Android et iPad.
Electrotechnique International (IEV) en ligne.

Recherche de publications IEC - www.iec.ch/searchpub
Glossaire IEC - std.iec.ch/glossary
Plus de 55 000 entrées terminologiques électrotechniques, en
La recherche avancée permet de trouver des publications IEC
en utilisant différents critères (numéro de référence, texte, anglais et en français, extraites des articles Termes et
comité d’études,…). Elle donne aussi des informations sur les Définitions des publications IEC parues depuis 2002. Plus
projets et les publications remplacées ou retirées. certaines entrées antérieures extraites des publications des

CE 37, 77, 86 et CISPR de l'IEC.
IEC Just Published - webstore.iec.ch/justpublished

Service Clients - webstore.iec.ch/csc
Restez informé sur les nouvelles publications IEC. Just
Published détaille les nouvelles publications parues. Si vous désirez nous donner des commentaires sur cette
Disponible en ligne et aussi une fois par mois par email. publication ou si vous avez des questions contactez-nous:
csc@iec.ch.
IEC 62501 ®
Edition 1.1 2014-08
CONSOLIDATED
VERSION
VERSION
CONSOLIDÉE
colour
inside
Voltage sourced converter (VSC) valves for high-voltage direct current (HVDC)

power transmission – Electrical testing

Valves à convertisseur de source de tension (VSC) pour le transport d’énergie

en courant continu à haute tension (CCHT) – Essais électriques

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.200; 29.240 ISBN 978-2-8322-1816-7

IEC 62501 ®
Edition 1.1 2014-08
REDLINE VERSION
VERSION REDLINE
colour
inside
Voltage sourced converter (VSC) valves for high-voltage direct current (HVDC)
power transmission – Electrical testing

Valves à convertisseur de source de tension (VSC) pour le transport d’énergie
en courant continu à haute tension (CCHT) – Essais électriques

– 2 – IEC 62501:2009
+AMD1:2014 CSV  IEC 2014
CONTENTS
FOREWORD. 0H0H5

1 Scope . 1H1H7

2 Normative references . 2H2H7

3 Terms and definitions . 3H3H7

3.1 Insulation co-ordination terms . 4H4H8

3.2 Power semiconductor terms . 5H5H8

3.3 Operating states of converter . 6H6H9

3.3.1 Operating state of an IGBT-diode pair . 7H7H
3.3.2 Operating state of converter . 8H8H
3.4 VSC construction terms . 9H9H9
3.5 Valve structure terms . 10H10H11
4 General requirements . 11H11H11
4.1 Guidelines for the performance of type tests . 12H12H11
4.1.1 Evidence in lieu . 13H13H11
4.1.2 Test object . 14H14H12
4.1.3 Sequence of test . 15H15H
4.1.4 Test procedure . 16H16H12
4.1.5 Ambient temperature for testing. 17H17H12
4.1.6 Frequency for testing . 18H18H12
4.1.7 Test reports . 19H19H12
4.1.8 Conditions to be considered in determination of type test parameters . 13
4.2 Atmospheric correction factor. 20H20H13
4.3 Treatment of redundancy . 21H21H13
4.3.1 Operational tests . 22H22H13
4.3.2 Dielectric tests . 23H23H13
4.4 Criteria for successful type testing . 24H24H14
4.4.1 General . 25H25H14
4.4.2 Criteria applicable to valve levels . 26H26H14
4.4.3 Criteria applicable to the valve as a whole . 27H27H15
5 List of type tests . 28H28H15
6 Operational tests . 29H29H16
6.1 Purpose of tests . 30H30H16

6.2 Test object . 31H31H16
6.3 Test circuit . 32H32H16
6.4 Maximum continuous operating duty test . 33H33H17
6.5 Maximum temporary over-load operating duty test . 34H34H17
6.6 Minimum d.c. voltage test . 35H35H18
7 Dielectric tests on valve support structure . 36H36H18
7.1 Purpose of tests . 37H37H18
7.2 Test object . 38H38H18
7.3 Test requirements . 39H39H19
7.3.1 Valve support d.c. voltage test . 40H40H19
7.3.2 Valve support a.c. voltage test . 41H41H20
7.3.3 Valve support switching impulse test . 42H42H20
7.3.4 Valve support lightning impulse test . 43H43H21
8 Dielectric tests on multiple valve unit . 44H44H21

+AMD1:2014 CSV  IEC 2014
8.1 Purpose of tests . 45H45H21

8.2 Test object . 46H46H21

8.3 Test requirements . 47H47H21

8.3.1 MVU d.c. voltage test to earth . 48H48H21

8.3.2 MVU a.c. voltage test . 49H49H22

8.3.3 MVU switching impulse test . 50H50H23

8.3.4 MVU lightning impulse test . 51H51H24

9 Dielectric tests between valve terminals . 52H52H24

9.1 Purpose of the test . 53H53H24

9.2 Test object . 54H54H25
9.3 Test requirements . 55H55H25
9.3.1 Valve a.c. – d.c. voltage test . 56H56H25
9.3.2 Valve impulse tests (general) . 57H57H27
9.3.3 Valve switching impulse test . 58H58H27
9.3.4 Valve lightning impulse test . 59H59H28
10 IGBT overcurrent turn-off test . 60H60H29
10.1 Purpose of test . 61H61H29
10.2 Test object . 62H62H29
10.3 Test requirements . 63H63H29
11 Short-circuit current test . 64H64H30
11.1 Purpose of tests . 65H65H30
11.2 Test object . 66H66H30
11.3 Test requirements . 67H67H30
12 Tests for valve insensitivity to electromagnetic disturbance . 68H68H30
12.1 Purpose of tests . 69H69H30
12.2 Test object . 70H70H31
12.3 Test requirements . 71H71H31
12.3.1 General . 72H72H31
12.3.2 Approach one . 73H73H31
12.3.3 Approach two . 74H74H31
12.3.4 Acceptance criteria . 75H75H32
13 Production tests . 76H76H32
13.1 Purpose of tests . 77H77H32
13.2 Test object . 78H78H33

13.3 Test requirements . 79H79H33
13.4 Production test objectives . 80H80H33
13.4.1 Visual inspection . 81H81H33
13.4.2 Connection check . 82H82H33
13.4.3 Voltage-grading circuit check . 83H83H33
13.4.4 Control, protection and monitoring circuit checks . 84H84H33
13.4.5 Voltage withstand check . 85H85H33
13.4.6 Partial discharge tests . 86H86H34
13.4.7 Turn-on / turn-off check . 87H87H34
13.4.8 Pressure test . 88H88H34
14 Presentation of type test results . 89H89H34
15 Tests for dynamic braking valves . 329
Annex A (informative) Overview of VSC topology converters in HVDC power
transmission . 90H90H35

– 4 – IEC 62501:2009
+AMD1:2014 CSV  IEC 2014
Annex B (informative) Valve component fault tolerance capability . 91H91H48

Bibliography . 92H92H49

Figure A.1 – A single VSC phase unit and its idealized output voltage . 93H93H36

Figure A.2 – Output voltage of a VSC phase unit for a 2-level converter . 94H94H36

Figure A.3 – Output voltage of a VSC phase unit for a 15-level converter, without PWM . 95H95H37

Figure A.4 – Basic circuit topology of one phase unit of a 2-level converter . 96H96H38

Figure A.5 – Basic circuit topology of one phase unit of a 3-level diode-clamped

converter . 97H97H39

Figure A.6 – Basic circuit topology of one phase unit of a 5-level diode-clamped
converter . 98H98H40
Figure A.7 – Basic circuit topology of one phase unit of a 3-level flying capacitor
converter . 99H99H41
Figure A.8 – A single VSC phase unit with valves of the “controllable voltage source”
type . 100H100H42
Figure A.9 – One possible implementation of a multi-level “voltage source” VSC valve
The half-bridge MMC circuit . 43
Figure A.10 – The full-bridge MMC circuit . 430H
Figure A.11 – The half-bridge CTL circuit . 45100H100H45
Figure A.12 – Construction terms in MMC valves . 46
Figure A.13 – Construction terms in CTL valves . 100H100H46

Table 1 – Minimum number of valve levels to be tested as a function of the number of
valve levels per valve . 102H102H12
Table 2 – Valve level faults permitted during type tests . 103H103H15
Table 3 – List of type tests . 104H104H15

+AMD1:2014 CSV  IEC 2014
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
VOLTAGE SOURCED CONVERTER (VSC)

VALVES FOR HIGH-VOLTAGE DIRECT CURRENT (HVDC)

POWER TRANSMISSION – ELECTRICAL TESTING

FOREWORD
1) 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.
2) 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.
3) 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.
4) 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.
5) 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.
6) All users should ensure that they have the latest edition of this publication.
7) 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.
8) 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.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

This Consolidated version of IEC 62501 bears the edition number 1.1. It consists of the
first edition (2009-06) [documents 22F/185/FDIS and 22F/193/RVD] and its amendment 1
(2014-08) [documents 22F/299/CDV and 22F/316A/RVC]. The technical content is
identical to the base edition and its amendment.
In this Redline version, a vertical line in the margin shows where the technical content
is modified by amendment 1. Additions and deletions are displayed in red, with
deletions being struck through. A separate Final version with all changes accepted is
available in this publication.
This publication has been prepared for user convenience.

– 6 – IEC 62501:2009
+AMD1:2014 CSV  IEC 2014
IEC 62501 has been prepared by subcommittee 22F: Power electronics for electrical
transmission and distribution systems, of IEC technical committee 22: Power electronic

systems and equipment.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

The committee has decided that the contents of the base publication and its amendment will
remain unchanged until the stability date indicated on the IEC web site under

"http://webstore.iec.ch" in the data related to the specific publication. At this date, the

publication will be
 reconfirmed,
 withdrawn,
 replaced by a revised edition, or
 amended.
IMPORTANT – The “colour inside” logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this publication using a colour printer.

+AMD1:2014 CSV  IEC 2014
VOLTAGE SOURCED CONVERTER (VSC)

VALVES FOR HIGH-VOLTAGE DIRECT CURRENT (HVDC)

POWER TRANSMISSION – ELECTRICAL TESTING

1 Scope
This International Standard applies to self-commutated converter valves, for use in a three-

phase bridge voltage sourced converter (VSC) for high voltage d.c. power transmission or as
part of a back-to-back link. It is restricted to electrical type and production tests.
The scope of this standard includes the electrical type and production tests of dynamic
braking valves which may be used in some HVDC schemes for d.c. overvoltage limitation.
This standard can be used as a guide for testing of STATCOM valves.
The tests specified in this standard are based on air insulated valves. For other types of
valves, the test requirements and acceptance criteria must should be agreed between the
purchaser and the supplier.
2 Normative references
The following referenced documents are indispensable for the application 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.
IEC 60060 (all parts), High-voltage test techniques
IEC 60060-1:1989, High-voltage test techniques – Part 1: General definitions and test
requirements
IEC 60071-1:2006, Insulation co-ordination – Part 1: Definitions, principles and rules
IEC 60071 (all parts), Insulation co-ordination
IEC 60270:2000, High-voltage test techniques – Partial discharge measurements

IEC 60700-1:1998, Thyristor valves for high voltage direct current (HVDC) power transmission
)
– Part 1: Electrical testing1F1F
Amendment 1(2003)
Amendment (2008)
ISO/IEC 17025, General requirements for the competence of testing and calibration
laboratories
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
___________
)
There exists a consolidated edition 1.2 (2008) that comprises IEC 60700-1, Amendment 1 and Amendment 2.

– 8 – IEC 62501:2009
+AMD1:2014 CSV  IEC 2014
3.1 Insulation co-ordination terms

3.1.1
test withstand voltage
value of a test voltage of standard waveshape at which a new valve, with unimpaired integrity,

does not show any disruptive discharge and meets all other acceptance criteria specified for
the particular test, when subjected to a specified number of applications or a specified

duration of the test voltage, under specified conditions

3.1.2
internal insulation
air external to the components and insulating materials of the valve, but contained within the

profile of the valve or multiple valve unit
3.1.3
external insulation
air between the external surface of the valve or multiple valve unit and its surroundings.
3.2 Power semiconductor terms
There are several types of controllable semiconductor switch device which can be used in
VSC converters for HVDC. For convenience, the term IGBT is used throughout this standard
to refer to the main, controllable, semiconductor switch device. However, the standard is
equally applicable to other types of controllable semiconductor switch device.
3.2.1
turn-off semiconductor device
controllable semiconductor device which may be turned on and off by a control signal, for
example an IGBT
NOTE There are several types of turn-off semiconductor devices which can be used in VSC converters for HVDC.
For convenience, the term IGBT is used throughout this standard to refer to the main turn-off semiconductor
device. However, the standard is equally applicable to other types of turn-off semiconductor devices.

3.2.13.2.2
insulated gate bipolar transistor
IGBT
a controllable switch with the capability to turn-on and turn-off a load current
An IGBT has turn-off semiconductor device with three terminals: a gate terminal (G) and two
load terminals emitter (E) and collector (C).
NOTE By applying appropriate gate to emitter voltages, the load current can be controlled, i.e. turned on and

turned off.
3.2.23.2.3
free-wheeling diode
FWD
power semiconductor device with diode characteristic
NOTE 1 A FWD has two terminals: an anode (A) and a cathode (K). The current through FWDs is in the opposite
direction to the IGBT current.
NOTE 2 FWDs are characterized by the capability to cope with high rates of decrease of current caused by the
switching behaviour of the IGBT.
3.2.33.2.4
IGBT-diode pair
arrangement of IGBT and FWD connected in inverse parallel

+AMD1:2014 CSV  IEC 2014
3.3 Operating states of converter

3.3.1 Operating state of an IGBT-diode pair

3.3.1.1
blocking state
condition in which an IGBT-diode pair is turned off

In that state, the load current does not flow through the IGBT. However, a load current can

flow through the diode as the diode is not controllable.

3.3.1.2
de-blocked state
the condition when the load current flows either through the IGBT or diode of an IGBT-diode
pair depending on the load current direction
3.3.2 Operating state of converter
3.3.2.13.3.1
blocking state
condition of the converter, in which a turn-off signal is applied continuously to all IGBTs of the
converter
NOTE Typically, the converter is in the blocking state condition after energization.
3.3.2.23.3.2
de-blocked state
condition of the converter, in which turn-on and turn-off signals are applied repetitively to
IGBTs of the converter
3.3.2.33.3.3
valve protective blocking
means of protecting the valve or converter from excessive electrical stress by the emergency
turn-off of all IGBTs in one or more valves
3.3.4
voltage step level
voltage step caused by switching of a valve or part of a valve during the de-blocked state of
the converter
NOTE For valves of the controllable voltage source type, the voltage step level corresponds to the change of
voltage caused by switching one submodule or cell. For valves of the switch type, the voltage step level
corresponds to the change of voltage caused by switching the complete valve.

3.4 VSC construction terms
3.4.1
VSC phase unit
equipment used to connect the two d.c. busbars to one a.c. terminal
3.4.2
switch type VSC valve
complete controllable device assembly, which represents a functional unit as part of a VSC
phase unit and characterized by switching actions of the power electronic devices upon
control signals of the converter base electronics arrangement of IGBT-diode pairs connected
in series and arranged to be switched simultaneously as a single function unit
NOTE Dependent on the converter topology, a valve can either have the function to act like a controllable switch
or to act like a controllable voltage source.

– 10 – IEC 62501:2009
+AMD1:2014 CSV  IEC 2014
3.4.3
controllable voltage source type VSC valve

complete controllable voltage source assembly, which is generally connected between one

a.c. terminal and one d.c. terminal

3.4.33.4.4
diode valve
semiconductor valve containing only diodes as the main semiconductor devices, which might

be used in some VSC topologies

3.4.5
dynamic braking valve
complete controllable device assembly, which is used to control energy absorption in braking
resistor
3.4.43.4.6
valve
VSC valve, dynamic braking valve or diode valve according to the context
3.4.7
submodule
part of a VSC valve comprising controllable switches and diodes connected to a half bridge or
full bridge arrangement, together with their immediate auxiliaries, storage capacitor, if any,
where each controllable switch consists of only one switched valve device connected in series
3.4.8
cell
MMC building block where each switch position consists of more than one IGBT-diode pair
connected in series
NOTE See Figure A.13
3.4.53.4.9
VSC valve level
part of a VSC valve comprising a controllable switch and an associated diode, or controllable
switches and diodes connected in parallel, or controllable switches and diodes connected to a
half bridge arrangement, together with their immediate auxiliaries, storage capacitor, if any
smallest indivisible functional unit of VSC valve
NOTE For any VSC valve in which IGBTs are connected in series and operated simultaneously, one VSC valve
level is one IGBT-diode pair including its auxiliaries (see Figure A.13). For MMC type without IGBT-diode pairs
connected in series one valve level is one submodule together with its auxiliaries (see Figure A.12).

3.4.63.4.10
diode valve level
part of a diode valve composed of a diode and associated circuits and components, if any
3.4.73.4.11
redundant levels
maximum number of series connected VSC valve levels or diode valve levels in a valve that
may be short-circuited externally or internally during service without affecting the safe
operation of the valve as demonstrated by type tests, and which if and when exceeded, would
require shutdown of the valve to replace the failed levels or acceptance of increased risk of
failures
NOTE In valve designs such as the cascaded two level converter, which contain two or more conduction paths
within each cell and have series-connected VSC valve levels in each path, redundant levels shall be counted only
in one conduction path in each cell.

+AMD1:2014 CSV  IEC 2014
3.4.12
dynamic braking valve level
part of a dynamic braking valve comprising a controllable switch and an associated diode, or

controllable switches and diodes connected in parallel, or controllable switches and diodes

connected to a half bridge arrangement, together with their immediate auxiliaries, storage

capacitor, if any
3.5 Valve structure terms
3.5.1
valve structure
physical structure holding the levels of a valve which is insulated to the appropriate voltage

above earth potential structural components of a valve, required in order to physically support
the valve modules
3.5.2
valve support
that part of the valve which mechanically supports and electrically insulates the active part of
the valve from earth
NOTE A part of a valve which is clearly identifiable in a discrete form to be a valve support may not exist in all
designs of valves.
3.5.3
multiple valve unit
MVU
mechanical arrangement of 2 or more valves or 1 or more VSC phase units sharing a common
valve support
NOTE A MVU might not exist in all topologies and physical arrangement of converters.
3.5.4
valve section
electrical assembly defined for test purposes, comprising a number of VSC or diode valve
levels and other components, which exhibits pro-rated electrical properties of a complete
valve
NOTE 1 For valves of controllable voltage source type the valve section shall include cell or submodule d.c.
capacitor in addition to VSC valve levels.
NOTE 2 The minimum number of VSC or diode valve levels allowed in a valve section is defined along with the
requirements of each test.
3.5.5
valve base electronics
electronic unit, at earth potential, which is the interface providing the electrical to optical
conversion between the converter control system and the VSC valves
4 General requirements
4.1 Guidelines for the performance of type tests
4.1.1 Evidence in lieu
Each design of valve shall be subjected to the type tests specified in this standard. If the
valve is demonstrably similar to one previously tested, the supplier may, in lieu of performing
a type test, submit a test report of a previous type test for consideration by the purchaser.
This should be accompanied by a separate report detailing the differences in the design and
demonstrating how the referenced type test satisfies the test objectives for the proposed
design.
– 12 – IEC 62501:2009
+AMD1:2014 CSV  IEC 2014
4.1.2 Test object
This subclause does not apply to tests on the valve supporting structure and multiple valve

unit. The test object for those tests is defined in 7.2 and 8.2.

a) Type tests may be performed either on a complete valve or, in certain circumstances, on

valve sections, as indicated in Table 3.

b) The minimum number of valve levels to be tested, depending on the valve levels in a

single valve, is as shown in Table 1.

Table 1 – Minimum number of valve levels to be tested as a function

of the number of valve levels per valve

Number of valve levels per valve Total number of valve levels to be tested
1 – 50 Number of valve levels in one valve
51 – 250 50
20 %
 251
c) Generally, the same valve sections are recommended to be used for all type tests.
However, with the agreement of the purchaser and supplier, different tests may be
performed on different valve sections in parallel, in order to speed up the programme for
executing the tests.
d) Prior to commencement of type tests, the valve, valve sections and/or the components of
them should be demonstrated to have withstood the production tests to ensure proper
manufacture.
4.1.3 Sequence of test
In order to confirm that the valve terminal-terminal insulation has not been degraded by the
fast repetitive switching stresses experienced by the converter in operation, the valve a.c. –
d.c. voltage test between terminals with partial discharge measurement should be performed
after the operational tests. Other type tests specified can be carried out in any order.
NOTE For valves of the “controllable voltage source” type (Clause A.5), the test sequence, where the a.c. – d.c.
voltage test is performed before the operational test, may be acceptable by mutual agreement between the
purchaser and supplier.
4.1.4 Test procedure
The tests shall be performed in accordance with IEC 60060, where applicable with due
account for IEC 60071 (all parts). Partial discharge measurements shall be performed in
accordance with IEC 60270.
4.1.5 Ambient temperature for testing
The tests shall be performed in accordance with IEC 60060, where applicable at the
prevailing ambient temperature of the test facility, unless otherwise specified.
4.1.6 Frequency for testing
AC dielectric tests can be performed at either 50 Hz or 60 Hz. For operational tests, specific
requirements regarding the frequency for testing are given in the relevant clauses.
NOTE Guidance on the worst service conditions can be found in CIGRÉ Technical Brochure No. 447.
4.1.7 Test reports
At the completion of the type tests, the supplier shall provide type test reports in accordance
with Clause 105H105H14.
+AMD1:2014 CSV  IEC 2014
4.1.8 Conditions to be considered in determination of type test parameters

Type test parameters should be determined based on the worst operating and fault conditions

to which the valve can be subjected, according to system studies. Guidance on the conditions

can be found in CIGRÉ Technical Brochure No. 447.

4.2 Atmospheric correction factor

When specified in the relevant clause, atmospheric correction shall be applied to the test

voltages in accordance with IEC 60060-1. The reference conditions to which correction shall

be made are the following:
– pressure:
 If the insulation coordination of the tested part of the valve is based on standard rated
withstand voltages according to IEC 60071-1, correction factors are only applied for
altitudes exceeding 1 000 m. Hence if the altitude of the site a at which the equipment
s
will be installed is 1 000 m, then the standard atmospheric air pressure (b =
101,3 kPa) shall be used with no correction for altitude. If a 1 000 m, then the
s
standard procedure according to IEC 60060-1 is used except that the reference
atmospheric pressure b is replaced by the atmospheric pressure corresponding to an
altitude of 1 000 m (b ).
1000m
 If the insulation coordination of the tested part of the valve is not based on standard
rated withstand voltages according to IEC 60071-1, then the standard procedure
according to IEC 60060-1 is used with the reference atmospheric pressure b
(b =101,3 kPa).
– temperature: design maximum valve hall air temperature (°C);
– humidity: design minimum valve hall absolute humidity (g/m ).
Realistic worst case combinations of temperature and humidity which can occur in practice
shall be used for atmospheric correction.
The values to be used shall be specified by the supplier.
4.3 Treatment of redundancy
4.3.1 Operational tests
For operational tests, redundant valve levels shall not be short-circuited. The test voltages
used shall be adjusted by means of a scaling factor k :
n
N
tut
k 
n
N  N
t r
where
N is the number of series valve levels in the test object;
tut
N  is the total number of series valve levels in the valve;
t
N  is the total number of redundant series valve levels in the valve.
r
4.3.2 Dielectric tests
For all dielectric tests between valve terminals
...

IEC 62501 ®
Edition 1.2 2017-09
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Voltage sourced converter (VSC) valves for high-voltage direct current (HVDC)
power transmission – Electrical testing

Valves à convertisseur de source de tension (VSC) pour le transport d’énergie
en courant continu à haute tension (CCHT) – Essais électriques

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.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite
ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie

et les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des

questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.

IEC Central Office Tel.: +41 22 919 02 11
3, rue de Varembé Fax: +41 22 919 03 00
CH-1211 Geneva 20 info@iec.ch
Switzerland www.iec.ch
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 corrigenda or an amendment might have been published.

IEC Catalogue - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
The stand-alone application for consulting the entire The world's leading online dictionary of electronic and
bibliographical information on IEC International Standards, electrical terms containing 20 000 terms and definitions in
Technical Specifications, Technical Reports and other English and French, with equivalent terms in 16 additional
documents. Available for PC, Mac OS, Android Tablets and languages. Also known as the International Electrotechnical
iPad. Vocabulary (IEV) online.

IEC publications search - www.iec.ch/searchpub IEC Glossary - std.iec.ch/glossary
The advanced search enables to find IEC publications by a 65 000 electrotechnical terminology entries in English and
variety of criteria (reference number, text, technical French extracted from the Terms and Definitions clause of
committee,…). It also gives information on projects, replaced IEC publications issued since 2002. Some entries have been
and withdrawn publications. collected from earlier publications of IEC TC 37, 77, 86 and

CISPR.
IEC Just Published - webstore.iec.ch/justpublished

Stay up to date on all new IEC publications. Just Published IEC Customer Service Centre - webstore.iec.ch/csc
details all new publications released. Available online and If you wish to give us your feedback on this publication or
also once a month by email. need further assistance, please contact the Customer Service
Centre: csc@iec.ch.
A propos de l'IEC
La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des
Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications IEC
Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la
plus récente, un corrigendum ou amendement peut avoir été publié.

Catalogue IEC - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
Application autonome pour consulter tous les renseignements
Le premier dictionnaire en ligne de termes électroniques et
bibliographiques sur les Normes internationales,
électriques. Il contient 20 000 termes et définitions en anglais
Spécifications techniques, Rapports techniques et autres
et en français, ainsi que les termes équivalents dans 16
documents de l'IEC. Disponible pour PC, Mac OS, tablettes
langues additionnelles. Egalement appelé Vocabulaire
Android et iPad.
Electrotechnique International (IEV) en ligne.

Recherche de publications IEC - www.iec.ch/searchpub
Glossaire IEC - std.iec.ch/glossary
La recherche avancée permet de trouver des publications IEC
65 000 entrées terminologiques électrotechniques, en anglais
en utilisant différents critères (numéro de référence, texte,
et en français, extraites des articles Termes et Définitions des
comité d’études,…). Elle donne aussi des informations sur les
publications IEC parues depuis 2002. Plus certaines entrées
projets et les publications remplacées ou retirées.
antérieures extraites des publications des CE 37, 77, 86 et

CISPR de l'IEC.
IEC Just Published - webstore.iec.ch/justpublished

Restez informé sur les nouvelles publications IEC. Just Service Clients - webstore.iec.ch/csc
Published détaille les nouvelles publications parues. Si vous désirez nous donner des commentaires sur cette
Disponible en ligne et aussi une fois par mois par email. publication ou si vous avez des questions contactez-nous:
csc@iec.ch.
IEC 62501 ®
Edition 1.2 2017-09
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Voltage sourced converter (VSC) valves for high-voltage direct current (HVDC)

power transmission – Electrical testing

Valves à convertisseur de source de tension (VSC) pour le transport d’énergie

en courant continu à haute tension (CCHT) – Essais électriques

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.200; 29.240.99 ISBN 978-2-8322-4857-7

IEC 62501 ®
Edition 1.2 2017-09
CONSOLIDATED VERSION
REDLINE VERSION
VERSION REDLINE
colour
inside
Voltage sourced converter (VSC) valves for high-voltage direct current (HVDC)
power transmission – Electrical testing

Valves à convertisseur de source de tension (VSC) pour le transport d’énergie
en courant continu à haute tension (CCHT) – Essais électriques

– 2 – IEC 62501:2009+AMD1:2014

+AMD2:2017 CSV  IEC 2017
CONTENTS
FOREWORD . 5

1 Scope . 7

2 Normative references . 7

3 Terms and definitions . 8

3.1 Insulation co-ordination terms . 8

3.2 Power semiconductor terms . 8

3.3 Operating states of converter . 9

3.3.1 Operating state of an IGBT-diode pair .
3.3.2 Operating state of converter .
3.4 VSC construction terms . 9
3.5 Valve structure terms . 11
4 General requirements . 11
4.1 Guidelines for the performance of type tests. 11
4.1.1 Evidence in lieu . 11
4.1.2 Selection of test object . 12
4.1.3 Sequence of test .
4.1.43 Test procedure . 12
4.1.54 Ambient temperature for testing . 12
4.1.65 Frequency for testing . 12
4.1.76 Test reports . 13
4.1.7 Conditions to be considered in determination of type test parameters . 13
4.2 Atmospheric correction factor . 13
4.3 Treatment of redundancy . 13
4.3.1 Operational tests . 13
4.3.2 Dielectric tests . 14
4.4 Criteria for successful type testing . 14
4.4.1 General . 14
4.4.2 Criteria applicable to valve levels . 14
4.4.3 Criteria applicable to the valve as a whole . 15
5 List of type tests . 15
6 Operational tests . 16
6.1 Purpose of tests . 16

6.2 Test object . 16
6.3 Test circuit . 17
6.4 Maximum continuous operating duty test . 17
6.5 Maximum temporary over-load operating duty test . 18
6.6 Minimum d.c. voltage test . 18
7 Dielectric tests on valve support structure . 19
7.1 Purpose of tests . 19
7.2 Test object . 19
7.3 Test requirements . 19
7.3.1 Valve support d.c. voltage test . 19
7.3.2 Valve support a.c. voltage test . 20
7.3.3 Valve support switching impulse test . 21
7.3.4 Valve support lightning impulse test . 21
8 Dielectric tests on multiple valve unit . 21

+AMD2:2017 CSV  IEC 2017
8.1 Purpose of tests . 22

8.2 Test object . 22

8.3 Test requirements . 22

8.3.1 MVU d.c. voltage test to earth . 22

8.3.2 MVU a.c. voltage test . 23

8.3.3 MVU switching impulse test . 24

8.3.4 MVU lightning impulse test . 25

9 Dielectric tests between valve terminals . 25

9.1 Purpose of the test . 25

9.2 Test object . 26
9.3 Test requirements . 26
9.3.1 Valve a.c. – d.c. voltage test . 26
9.3.2 Valve impulse tests (general) . 28
9.3.3 Valve switching impulse test . 28
9.3.4 Valve lightning impulse test . 29
9.4 Test methods . 30
9.4.1 General . 30
9.4.2 Method one . 30
9.4.3 Method two . 30
10 IGBT overcurrent turn-off test . 30
10.1 Purpose of test . 30
10.2 Test object . 31
10.3 Test requirements . 31
11 Short-circuit current test . 31
11.1 Purpose of tests . 31
11.2 Test object . 31
11.3 Test requirements . 32
12 Tests for valve insensitivity to electromagnetic disturbance . 32
12.1 Purpose of tests . 32
12.2 Test object . 32
12.3 Test requirements . 33
12.3.1 General . 33
12.3.2 Approach one . 33
12.3.3 Approach two . 33
12.3.4 Acceptance criteria . 33
13 Production tests . 34
13.1 Purpose of tests . 34
13.2 Test object . 34
13.3 Test requirements . 34
13.4 Production test objectives . 35
13.4.1 Visual inspection . 35
13.4.2 Connection check . 35
13.4.3 Voltage-grading circuit check . 35
13.4.4 Control, protection and monitoring circuit checks . 35
13.4.5 Voltage withstand check . 35
13.4.6 Partial discharge tests . 35
13.4.7 Turn-on / turn-off check . 35
13.4.8 Pressure test . 35

– 4 – IEC 62501:2009+AMD1:2014

+AMD2:2017 CSV  IEC 2017
14 Presentation of type test results . 35

15 Tests for dynamic braking valves . 33

Annex A (informative) Overview of VSC topology converters in HVDC power

transmission . 37

Annex B (informative) Valve component fault tolerance capability . 50

Bibliography . 51

Figure A.1 – A single VSC phase unit and its idealized output voltage . 38

Figure A.2 – Output voltage of a VSC phase unit for a 2-level converter . 38

Figure A.3 – Output voltage of a VSC phase unit for a 15-level converter, without PWM . 39
Figure A.4 – Basic circuit topology of one phase unit of a 2-level converter . 40
Figure A.5 – Basic circuit topology of one phase unit of a 3-level diode-clamped
converter . 41
Figure A.6 – Basic circuit topology of one phase unit of a 5-level diode-clamped
converter . 42
Figure A.7 – Basic circuit topology of one phase unit of a 3-level flying capacitor
converter . 43
Figure A.8 – A single VSC phase unit with controllable voltage source type VSC valves
of the “controllable voltage source” type . 44
Figure A.9 – One possible implementation of a multi-level “voltage source” VSC valve .
Figure A.9 – The half-bridge MMC circuit . 45
Figure A.10 – The full-bridge MMC circuit . 45
Figure A.11 – The half-bridge CTL circuit . 47
Figure A.12 – Construction terms in MMC valves . 48
Figure A.13 – Construction terms in CTL valves. 48

Table 1 – Minimum number of valve levels to be operational type tested as a function
of the number of valve levels per valve . 12
Table 2 – Valve level faults permitted during type tests . 15
Table 3 – List of type tests . 16

+AMD2:2017 CSV  IEC 2017
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
VOLTAGE SOURCED CONVERTER (VSC)

VALVES FOR HIGH-VOLTAGE DIRECT CURRENT (HVDC)

POWER TRANSMISSION – ELECTRICAL TESTING

FOREWORD
1) 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.
2) 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.
3) 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.
4) 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.
5) 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.
6) All users should ensure that they have the latest edition of this publication.
7) 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.
8) 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.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

This consolidated version of the official IEC Standard and its amendments has been prepared
for user convenience.
IEC 62501 edition 1.2 contains the first edition (2009-06) [documents 22F/185/FDIS and 22F/193/
RVD], its amendment 1 (2014-08) [documents 22F/299/CDV and 22F/316A/RVC] and its
amendment 2 (2017-09) [documents 22F/438/CDV and 22F/457/RVC].
In this Redline version, a vertical line in the margin shows where the technical content is
modified by amendments 1 and 2. Additions are in green text, deletions are in
strikethrough red text. A separate Final version with all changes accepted is available in this
publication.
– 6 – IEC 62501:2009+AMD1:2014

+AMD2:2017 CSV  IEC 2017
IEC 62501 has been prepared by subcommittee 22F: Power electronics for electrical
transmission and distribution systems, of IEC technical committee 22: Power electronic

systems and equipment.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

The committee has decided that the contents of the base publication and its amendments will
remain unchanged until the stability date indicated on the IEC web site under

"http://webstore.iec.ch" in the data related to the specific publication. At this date, the

publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The “colour inside” logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this publication using a colour printer.

+AMD2:2017 CSV  IEC 2017
VOLTAGE SOURCED CONVERTER (VSC)

VALVES FOR HIGH-VOLTAGE DIRECT CURRENT (HVDC)

POWER TRANSMISSION – ELECTRICAL TESTING

1 Scope
This International Standard applies to self-commutated converter valves, for use in a three-

phase bridge voltage sourced converter (VSC) for high voltage d.c. power transmission or as
part of a back-to-back link. It is restricted to electrical type and production tests.
The scope of this standard includes the electrical type and production tests of dynamic
braking valves which may be used in some HVDC schemes for d.c. overvoltage limitation.
The tests specified in this standard are based on air insulated valves. For other types of
valves, the test requirements and acceptance criteria must should be agreed between the
purchaser and the supplier.
2 Normative references
The following referenced documents are indispensable for the application 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.
IEC 60060 (all parts), High-voltage test techniques
IEC 60060-1:1989, High-voltage test techniques – Part 1: General definitions and test
requirements
IEC 60071-1:2006, Insulation co-ordination – Part 1: Definitions, principles and rules
IEC 60071 (all parts), Insulation co-ordination
IEC 60270, High-voltage test techniques – Partial discharge measurements
IEC 60700-1:1998 2015, Thyristor valves for high voltage direct current (HVDC) power
)
transmission – Part 1: Electrical testing

Amendment 1(2003)
Amendment (2008)
IEC 62747, Terminology for voltage-sourced converters (VSC) for high-voltage direct current
(HVDC) systems
ISO/IEC 17025, General requirements for the competence of testing and calibration
laboratories
3 Terms and definitions
For the purposes of this document, the following terms and definitions given in IEC 62747 and
the following apply.
___________
)
There exists a consolidated edition 1.2 (2008) that comprises IEC 60700-1, Amendment 1 and Amendment 2.

– 8 – IEC 62501:2009+AMD1:2014

+AMD2:2017 CSV  IEC 2017
3.1 Insulation co-ordination terms

3.1.1
test withstand voltage
value of a test voltage of standard waveshape at which a new valve, with unimpaired integrity,

does not show any disruptive discharge and meets all other acceptance criteria specified for
the particular test, when subjected to a specified number of applications or a specified

duration of the test voltage, under specified conditions

3.1.2
internal insulation
air external to the components and insulating materials of the valve, but contained within the

profile of the valve or multiple valve unit
3.1.3
external insulation
air between the external surface of the valve or multiple valve unit and its surroundings.
3.2 Power semiconductor terms
There are several types of controllable semiconductor switch device which can be used in
VSC converters for HVDC. For convenience, the term IGBT is used throughout this standard
to refer to the main, controllable, semiconductor switch device. However, the standard is
equally applicable to other types of controllable semiconductor switch device.
3.2.1
turn-off semiconductor device
controllable semiconductor device which may be turned on and off by a control signal, for
example an IGBT
NOTE There are several types of turn-off semiconductor devices which can be used in VSC converters for HVDC.
For convenience, the term IGBT is used throughout this standard to refer to the main turn-off semiconductor
device. However, the standard is equally applicable to other types of turn-off semiconductor devices.

3.2.13.2.2
insulated gate bipolar transistor
IGBT
a controllable switch with the capability to turn-on and turn-off a load current
An IGBT has turn-off semiconductor device with three terminals: a gate terminal (G) and two
load terminals emitter (E) and collector (C).
NOTE By applying appropriate gate to emitter voltages, the load current can be controlled, i.e. turned on and
turned off.
3.2.23.2.3
free-wheeling diode
FWD
power semiconductor device with diode characteristic
NOTE 1 A FWD has two terminals: an anode (A) and a cathode (K). The current through FWDs is in the opposite
direction to the IGBT current.
NOTE 2 FWDs are characterized by the capability to cope with high rates of decrease of current caused by the
switching behaviour of the IGBT.
3.2.33.2.4
IGBT-diode pair
arrangement of IGBT and FWD connected in inverse parallel

+AMD2:2017 CSV  IEC 2017
3.3 Operating states of converter

3.3.1 Operating state of an IGBT-diode pair

3.3.1.1
blocking state
condition in which an IGBT-diode pair is turned off

In that state, the load current does not flow through the IGBT. However, a load current can

flow through the diode as the diode is not controllable.

3.3.1.2
de-blocked state
the condition when the load current flows either through the IGBT or diode of an IGBT-diode
pair depending on the load current direction
3.3.2 Operating state of converter
3.3.2.13.3.1
blocking state
condition of the converter, in which a turn-off signal is applied continuously to all IGBTs of the
converter
NOTE Typically, the converter is in the blocking state condition after energization.
3.3.2.23.3.2
de-blocked state
condition of the converter, in which turn-on and turn-off signals are applied repetitively to
IGBTs of the converter
3.3.2.33.3.3
valve protective blocking
means of protecting the valve or converter from excessive electrical stress by the emergency
turn-off of all IGBTs in one or more valves
3.3.4
voltage step level
voltage step caused by switching of a valve or part of a valve during the de-blocked state of
the converter
NOTE For valves of the controllable voltage source type, the voltage step level corresponds to the change of
voltage caused by switching one submodule or cell. For valves of the switch type, the voltage step level
corresponds to the change of voltage caused by switching the complete valve.

3.4 VSC construction terms
3.4.1
VSC phase unit
equipment used to connect the two d.c. busbars to one a.c. terminal
3.4.2
switch type VSC valve
complete controllable device assembly, which represents a functional unit as part of a VSC
phase unit and characterized by switching actions of the power electronic devices upon
control signals of the converter base electronics
arrangement of IGBT-diode pairs connected in series and arranged to be switched
simultaneously as a single function unit
NOTE Dependent on the converter topology, a valve can either have the function to act like a controllable switch
or to act like a controllable voltage source.

– 10 – IEC 62501:2009+AMD1:2014

+AMD2:2017 CSV  IEC 2017
3.4.3
controllable voltage source type VSC valve

complete controllable voltage source assembly, which is generally connected between one

a.c. terminal and one d.c. terminal

3.4.33.4.4
diode valve
semiconductor valve containing only diodes as the main semiconductor devices, which might

be used in some VSC topologies

3.4.5
dynamic braking valve
complete controllable device assembly, which is used to control energy absorption in braking
resistor
3.4.43.4.6
valve
VSC valve, dynamic braking valve or diode valve according to the context
3.4.7
submodule
part of a VSC valve comprising controllable switches and diodes connected to a half bridge or
full bridge arrangement, together with their immediate auxiliaries, storage capacitor, if any,
where each controllable switch consists of only one switched valve device connected in series
3.4.8
cell
MMC building block where each switch position consists of more than one IGBT-diode pair
connected in series
NOTE See Figure A.13
3.4.53.4.9
VSC valve level
part of a VSC valve comprising a controllable switch and an associated diode, or controllable
switches and diodes connected in parallel, or controllable switches and diodes connected to a
half bridge arrangement, together with their immediate auxiliaries, storage capacitor, if any
smallest indivisible functional unit of VSC valve
NOTE For any VSC valve in which IGBTs are connected in series and operated simultaneously, one VSC valve
level is one IGBT-diode pair including its auxiliaries (see Figure A.13). For MMC type without IGBT-diode pairs
connected in series one valve level is one submodule together with its auxiliaries (see Figure A.12).

3.4.63.4.10
diode valve level
part of a diode valve composed of a diode and associated circuits and components, if any
3.4.73.4.11
redundant levels
maximum number of series connected VSC valve levels or diode valve levels in a valve that
may be short-circuited externally or internally during service without affecting the safe
operation of the valve as demonstrated by type tests, and which if and when exceeded, would
require shutdown of the valve to replace the failed levels or acceptance of increased risk of
failures
NOTE In valve designs such as the cascaded two level converter, which contain two or more conduction paths
within each cell and have series-connected VSC valve levels in each path, redundant levels shall be counted only
in one conduction path in each cell.

+AMD2:2017 CSV  IEC 2017
3.4.12
dynamic braking valve level
part of a dynamic braking valve comprising a controllable switch and an associated diode, or

controllable switches and diodes connected in parallel, or controllable switches and diodes

connected to a half bridge arrangement, together with their immediate auxiliaries, storage

capacitor, if any
3.5 Valve structure terms
3.5.1
valve structure
physical structure holding the levels of a valve which is insulated to the appropriate voltage

above earth potential
structural components of a valve, required in order to physically support the valve modules
3.5.2
valve support
that part of the valve which mechanically supports and electrically insulates the active part of
the valve from earth
NOTE A part of a valve which is clearly identifiable in a discrete form to be a valve support may not exist in all
designs of valves.
3.5.3
multiple valve unit
MVU
mechanical arrangement of 2 or more valves or 1 or more VSC phase units sharing a common
valve support
NOTE A MVU might not exist in all topologies and physical arrangement of converters.
3.5.4
valve section
electrical assembly defined for test purposes, comprising a number of VSC or diode valve
levels and other components, which exhibits pro-rated electrical properties of a complete
valve
NOTE 1 For valves of controllable voltage source type the valve section shall include cell or submodule d.c.
capacitor in addition to VSC valve levels.
NOTE 2 The minimum number of VSC or diode valve levels allowed in a valve section is defined along with the
requirements of each test.
3.5.5
valve base electronics
electronic unit, at earth potential, which is the interface between the converter control system
and the VSC valves
4 General requirements
4.1 Guidelines for the performance of type tests
4.1.1 Evidence in lieu
Each design of valve shall be subjected to the type tests specified in this standard. If the
valve is demonstrably similar to one previously tested, the supplier may, in lieu of performing
a type test, submit a test report of a previous type test for consideration by the purchaser.
This should be accompanied by a separate report detailing the differences in the design and
demonstrating how the referenced type test satisfies the test objectives for the proposed
design.
– 12 – IEC 62501:2009+AMD1:2014

+AMD2:2017 CSV  IEC 2017
4.1.2 Selection of test object

This subclause does not apply to tests on the valve supporting structure and multiple valve

unit. The test object for those tests is defined in 7.2 and 8.2.

a) Type tests may be performed either on a complete valve or, in certain circumstances, on

valve sections, as indicated in Table 3.

b) The minimum number of valve levels to be operational type tested, depending on the valve

levels in a single valve, is as shown in Table 1.

Table 1 – Minimum number of valve levels to be operational type tested as a function

of the number of valve levels per valve

Number of valve levels per valve Total number of valve levels to be tested
1 – 50 Number of valve levels in one valve
51 – 250 50
20 %
≥ 251
The minimum number of valve levels to be dielectric type tested can be equal to or lower than
the number specified for the operational type test.

The minimum number of valve levels, however, shall be representative to the valve dielectric
design. Details can be found in 9.2.
c) Generally, the same valve sections are recommended to be used for all type tests.
However, with the agreement of the purchaser and supplier, different tests may be
performed on different valve sections in parallel, in order to speed up the programme for
executing the tests.
d) Prior to commencement of type tests, the valve, valve sections and/or the components of
them should be demonstrated to have withstood the production tests to ensure proper
manufacture.
4.1.3 Sequence of test
In order to confirm that the valve terminal-terminal insulation has not been degraded by the
fast repetitive switching stresses experienced by the converter in operation, the valve a.c. –
d.c. voltage test between terminals with partial discharge measurement should be performed
after the operational tests. Other type tests specified can be carried out in any order.
NOTE For valves of the “controllable voltage source” type (Clause A.5), the test sequence, where the a.c. – d.c.
voltage test is performed before the operational test, may be acceptable by mutual agreement between the
purchaser and supplier.
4.1.44.1.3 Test procedure
The tests shall be performed in accordance with IEC 60060, where applicable with due
account for IEC 60071 (all parts). Partial discharge measurements shall be performed in
accordance with IEC 60270.
4.1.54.1.4 Ambient temperature for testing
The tests shall be performed in accordance with IEC 60060, where applicable at the
prevailing ambient temperature of the test facility, unless otherwise specified.
4.1.64.1.5 Frequency for testing
AC dielectric tests can be performed at either 50 Hz or 60 Hz. For operational tests, specific
requirements regarding the frequency for testing are given in the relevant clauses.

+AMD2:2017 CSV  IEC 2017
4.1.74.1.6 Test reports
At the completion of the type tests, the supplier shall provide type test reports in accordance

with Clause 14.
4.1.7 Conditions to be considered in determination of type test parameters

Type test parameters should be determined based on the worst operating and fault conditions
to which the valve can be subjected, according to system studies. Guidance on the conditions

can be found in CIGRÉ Technical Brochure No. 447.

4.2 Atmospheric correction factor

When specified in the relevant clause, atmospheric correction shall be applied to the test
voltages in accordance with IEC 60060-1. The reference conditions to which correction shall
be made are the following:
– pressure:
• If the insulation coordination of the tested part of the valve is based on standard rated
withstand voltages according to IEC 60071-1, correction factors are only applied for
altitudes exceeding 1 000 m. Hence if the altitude of the site a at which the equipment
s
will be installed is ≤1 000 m, then the standard atmospheric air pressure (b =
101,3 kPa) shall be used with no correction for altitude. If a >1 000 m, then the
s
standard procedure according to IEC 60060-1 is used except that the reference
atmospheric pressure b is replaced by the atmospheric pressure corresponding to an
altitude of 1 000 m (b ).
1000m
• If the insulation coordination of the tested part of the valve is not based on standard
rated withstand voltages according to IEC 60071-1, then the standard procedure
according to IEC 60060-1 is used with the reference atmospheric pressure b
(b =101,3 kPa).
– temperature: design maximum valve hall air temperature (°C);
– humidity: design minimum valve hall absolute humidity (g/m ).
Realistic worst case combinations of temperature and humidity which can occur in practice
shall be used for atmospheric correction.
The values to be used shall be specified by the supplier.
4.3 Treatment of redundancy
4.3.1 Operational tests
For operational tests, redundant valve l
...