High-voltage direct current (HVDC) transmission - Vocabulary (IEC 60633:2019)

This Standard defines terms for high-voltage direct current (HVDC) power transmission systems and for HVDC substations using electronic power converters for the conversion from AC to DC or vice versa. This document is applicable to HVDC substations with line commutated converters, most commonly based on three-phase bridge (double way) connections (see Figure 2) in which unidirectional electronic valves, for example semiconductor valves, are used. For the thyristor valves, only the most important definitions are included in this document. A more comprehensive list of HVDC valve terminology is given in IEC 60700-2.

High-voltage direct current (HVDC) transmission - Vocabulary (IEC 60633:2019)

Transport d'énergie en courant continu à haute tension (CCHT) - Vocabulaire (IEC 60633:2019)

IEC 60633:2019 est disponible sous forme de IEC 60633:2019 RLV qui contient la Norme internationale et sa version Redline, illustrant les modifications du contenu technique depuis l'édition précédente.IEC 60633:2019 définit les termes relatifs aux systèmes de transport de puissance en courant continu à haute tension (CCHT), et aux postes CCHT utilisant des convertisseurs électroniques de puissance pour la conversion du courant alternatif en courant continu ou inversement. Le présent document est applicable aux postes CCHT avec des convertisseurs commutés par le réseau, fondés le plus souvent sur le schéma en pont triphasé (deux voies) (voir Figure 2) dans lequel des valves électroniques unidirectionnelles, comme les valves à semiconducteurs, sont utilisées. Pour les valves à thyristors, seules les définitions les plus importantes sont incluses dans le présent document. Une liste plus complète de la terminologie des valves CCHT est donnée dans l’IEC 60700-2. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente: - 40 termes et définitions ont été modifiés et 31 nouveaux termes et définitions ont été ajoutés principalement pour les unités de conversion et les valves, les conditions de fonctionnement du convertisseur, les systèmes et postes CCHT et les équipements des postes CCHT; - une nouvelle Figure 13 portant sur les configurations à convertisseurs commutés a été ajoutée.

Visokonapetostni enosmerni prenos (HVDC) - Slovar (IEC 60633:2019)

Ta standard določa izraze za visokonapetostne enosmerne (HVDC) sisteme prenosa moči in visokonapetostne enosmerne naprave, ki uporabljajo elektronske močnostne pretvornike za pretvorbo izmeničnega toka v enosmerni tok in obratno. Ta dokument se uporablja za visokonapetostne enosmerne naprave z vodovno komutiranimi pretvorniki, ki običajno temeljijo na povezavah trifaznega mostu (dvosmernih) (glej sliko 2), v katerem so uporabljene enosmerne elektronke, npr. polprevodniške elektronke. Za tiristorske elektronke so v tem dokumentu vključene samo najpomembnejše definicije. Obsežnejši seznam terminologije za visokonapetostne enosmerne elektronke je podan v standardu IEC 60700-2.

General Information

Status
Published
Public Enquiry End Date
24-Apr-2018
Publication Date
20-Nov-2019
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
01-Aug-2019
Due Date
06-Oct-2019
Completion Date
21-Nov-2019

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SLOVENSKI STANDARD
SIST EN IEC 60633:2020
01-januar-2020
Nadomešča:
SIST EN 60633:2001
SIST EN 60633:2001/A1:2010
SIST EN 60633:2001/A2:2015
Visokonapetostni enosmerni prenos (HVDC) - Slovar (IEC 60633:2019)
High-voltage direct current (HVDC) transmission - Vocabulary (IEC 60633:2019)
High-voltage direct current (HVDC) transmission - Vocabulary (IEC 60633:2019)
Transport d'énergie en courant continu à haute tension (CCHT) - Vocabulaire (IEC
60633:2019)
Ta slovenski standard je istoveten z: EN IEC 60633:2019
ICS:
01.040.29 Elektrotehnika (Slovarji) Electrical engineering
(Vocabularies)
29.200 Usmerniki. Pretvorniki. Rectifiers. Convertors.
Stabilizirano električno Stabilized power supply
napajanje
SIST EN IEC 60633:2020 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN IEC 60633:2020
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SIST EN IEC 60633:2020
EUROPEAN STANDARD EN IEC 60633
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2019
ICS 29.200 Supersedes EN 60633:1999
English Version
High-voltage direct current (HVDC) transmission - Vocabulary
(IEC 60633:2019)

Transport d'énergie en courant continu à haute tension Hochspannungsgleichstrom-Übertragung (HGÜ) - Begriffe

(CCHT) - Vocabulaire (IEC 60633:2019)
(IEC 60633:2019)

This European Standard was approved by CENELEC on 2019-05-30. 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,

Turkey 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

© 2019 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN IEC 60633:2019 E
---------------------- Page: 3 ----------------------
SIST EN IEC 60633:2020
EN IEC 60633:2019 (E)
European foreword

The text of document 22F/480/CDV, future edition 3 of IEC 60633, prepared by SC 22F "Power

electronics for electrical transmission and distribution systems" of IEC/TC 22 "Power electronic

systems and equipment" was submitted to the IEC-CENELEC parallel vote and approved by

CENELEC as EN IEC 60633:2019.
The following dates are fixed:

• latest date by which the document has to be implemented at national (dop) 2020-02-28

level by publication of an identical national standard or by endorsement

• latest date by which the national standards conflicting with the (dow) 2022-05-30

document have to be withdrawn
This document supersedes EN 60633:1999.

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.

Endorsement notice

The text of the International Standard IEC 60633:2019 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:
IEC 60027 (series) NOTE Harmonized as EN 60027 (series)
IEC 60076 (series) NOTE Harmonized as EN 60076 (series)
IEC 60099 (series) NOTE Harmonized as EN 60099 (series)
IEC 60146-1-1 NOTE Harmonized as EN 60146-1-1
IEC 60146-1-3:1991 NOTE Harmonized as EN 60146-1-3:1993 (not modified)
IEC 60700-2 NOTE Harmonized as EN 60700-2
IEC/TR 60919-2:2008 NOTE Harmonized as CLC/TR 60919-2:2010 (not modified)
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SIST EN IEC 60633:2020
IEC 60633
Edition 3.0 2019-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
High-voltage direct current (HVDC) transmission – Vocabulary
Transport d'énergie en courant continu à haute tension (CCHT) – Vocabulaire
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.200 ISBN 978-2-8322-6812-4

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 IEC 60633:2020
– 2 – IEC 60633:2019 © IEC 2019
CONTENTS

FOREWORD ........................................................................................................................... 3

1 Scope .............................................................................................................................. 5

2 Normative references ...................................................................................................... 5

3 Symbols and abbreviated terms ....................................................................................... 5

3.1 Letter symbols ........................................................................................................ 5

3.2 Subscripts ............................................................................................................... 6

3.3 Abbreviated terms ................................................................................................... 6

4 Graphical symbols ........................................................................................................... 6

5 General terms related to converter circuits ...................................................................... 6

6 Converter units and valves .............................................................................................. 9

7 Converter operating conditions ...................................................................................... 12

8 HVDC systems and substations ..................................................................................... 15

9 HVDC substation equipment .......................................................................................... 19

10 Modes of control ............................................................................................................ 23

11 Control systems ............................................................................................................. 23

12 Control functions ........................................................................................................... 26

Bibliography .......................................................................................................................... 37

Figure 1 – Graphical symbols ................................................................................................ 27

Figure 2 – Bridge converter connection ................................................................................. 27

Figure 3 – Example of a converter unit .................................................................................. 28

Figure 4 – Commutation process at rectifier and inverter modes of operation ........................ 29

Figure 5 – Illustrations of commutation in inverter operation ................................................. 30

Figure 6 – Typical valve voltage waveforms .......................................................................... 31

Figure 7 – Example of an HVDC substation .......................................................................... 32

Figure 8 – Example of bipolar two-terminal HVDC transmission system ................................ 33

Figure 9 – Example of a multiterminal bipolar HVDC transmission system with parallel

connected HVDC substations ................................................................................................ 33

Figure 10 – Example of a multiterminal HVDC transmission system with series

connected HVDC substations ................................................................................................ 34

Figure 11 – Simplified steady-state voltage-current characteristic of a two-terminal

HVDC system ....................................................................................................................... 34

Figure 12 – Hierarchical structure of an HVDC control system .............................................. 35

Figure 13 – Capacitor commutated converter configurations ................................................. 36

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SIST EN IEC 60633:2020
IEC 60633:2019 © IEC 2019 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HIGH-VOLTAGE DIRECT CURRENT
(HVDC) TRANSMISSION – VOCABULARY
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.

International Standard IEC 60633 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 third edition cancels and replaces the second edition published in 1998,

Amendment 1:2009 and Amendment 2:2015. This edition constitutes a technical revision.

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

edition:

a) 40 terms and definitions have been amended and 31 new terms and definitions have been

added mainly on converter units and valves, converter operating conditions, HVDC
systems and substations and HVDC substation equipment;

b) a new Figure 13 on capacitor commutated converter configurations has been added.

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SIST EN IEC 60633:2020
– 4 – IEC 60633:2019 © IEC 2019
The text of this International Standard is based on the following documents:
CDV Report on voting
22F/480/CDV 22F/491A/RVC

Full information on the voting for the approval of this International Standard can be found in

the report on voting indicated in the above table.

This document has been drafted in accordance with the ISO/IEC Directives, Part 2.

The committee has decided that the contents of this document will remain unchanged until the

stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to

the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
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SIST EN IEC 60633:2020
IEC 60633:2019 © IEC 2019 – 5 –
HIGH-VOLTAGE DIRECT CURRENT
(HVDC) TRANSMISSION – VOCABULARY
1 Scope

This document defines terms for high-voltage direct current (HVDC) power transmission

systems and for HVDC substations using electronic power converters for the conversion from

AC to DC or vice versa.

This document is applicable to HVDC substations with line commutated converters, most

commonly based on three-phase bridge (double way) connections (see Figure 2) in which

unidirectional electronic valves, for example semiconductor valves, are used. For the thyristor

valves, only the most important definitions are included in this document. A more

comprehensive list of HVDC valve terminology is given in IEC 60700-2.
2 Normative references
There are no normative references in this document.
3 Symbols and abbreviated terms

The list covers only the most frequently used symbols. For a more complete list of the

symbols which have been adopted for static converters, see IEC 60027 (all parts) and other

standards listed in the Bibliography.
3.1 Letter symbols
U direct voltage (any defined value)
U nominal no-load direct voltage
ideal no-load direct voltage
di0
U rated direct voltage

U phase-to-phase voltage on line side of converter transformer, RMS value including

harmonics
U U
rated value of
LN L
U RMS value
no-load phase-to-phase voltage on the valve side of transformer,
excluding harmonics
direct current (any defined value)
I rated direct current
current on line side of converter transformer, RMS value including harmonics
I rated value of I
LN L
current on valve side of transformer, RMS value including harmonics
α (trigger) delay angle
β (trigger) advance angle
γ extinction angle
µ overlap angle
p pulse number
q commutation number
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SIST EN IEC 60633:2020
– 6 – IEC 60633:2019 © IEC 2019
3.2 Subscripts
0 (zero) at no load
N rated value or at rated load
d direct current or voltage
i ideal
L line side of converter transformer
v valve side of converter transformer
max maximum
min minimum
n pertaining to harmonic component of order n
3.3 Abbreviated terms
The following abbreviated terms are always in capital letters and without dots.
HVDC high-voltage direct current
MVU multiple valve (unit) (see 6.3.2)
SCR short-circuit ratio (see 7.32)
ESCR effective short-circuit ratio (see 7.33)
MTDC multiterminal HVDC transmission system (see 8.2.2)
MRTB metallic return transfer breaker (see 9.22)
ERTB earth return transfer breaker (see 9.23)
VDCOL voltage dependent current order limit (see 12.9)
SSTI sub-synchronous torsional interaction (see 10.10)
4 Graphical symbols

Figure 1 shows the specific graphical symbols which are defined only for the purposes of this

document. For a more complete list of the graphical symbols which have been adopted for

static converters, see IEC 60617.
5 General terms related to converter circuits
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp

NOTE For a more complete list of the terms which have been adopted for static converters, see IEC 60050-551

and IEC 60146-1-1.
5.1
conversion

transfer of energy from AC to DC or vice versa, or a combination of these operations

5.2
converter connection

electrical arrangement of arms and other components necessary for the functioning of the

main power circuit of a converter
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SIST EN IEC 60633:2020
IEC 60633:2019 © IEC 2019 – 7 –
5.3
bridge converter connection

double-way connection comprising six converter arms such that the centre terminals are the

phase terminals of the AC circuit, and that the outer terminals of like polarity are connected

together and are the DC terminals
Note 1 to entry: The double-way connection is illustrated in Figure 2.
5.3.1
uniform bridge
bridge where all converter arms are either controllable or non-controllable
5.3.2
non-uniform bridge
bridge with both controllable and non-controllable converter arms
5.4
converter arm

part of a bridge connecting two points of different potentials within a bridge, for example,

between an AC terminal and a DC terminal
5.4.1
controllable converter arm

converter arm in which the start of forward conduction may be determined by an externally

applied signal
5.4.2
non-controllable converter arm

converter arm in which the start of forward conduction is determined solely by the voltage

applied to its terminals
5.5
by-pass path

low resistance path between the DC terminals of one or several bridges excluding the AC

circuit

Note 1 to entry: The by-pass path may either constitute a unidirectional path, e.g. a by-pass arm (see 5.5.1), or a

by-pass pair (see 5.5.2), or it may constitute a bidirectional path, e.g. a by-pass switch (see 9.30).

5.5.1
by-pass arm

unidirectionally conducting by-pass path connected only between DC terminals, commonly

used with mercury arc valve technology
Note 1 to entry: By-pass arm is not shown in Figure 2.
5.5.2
by-pass pair

two converter arms of a bridge connected to a common AC terminal and forming a by-pass

path
SEE: Figure 2.
5.6
commutation

transfer of current between any two paths with both paths carrying current simultaneously

during this process

Note 1 to entry: Commutation may occur between any two converter arms, including the connected AC phases,

between a converter arm and a by-pass arm, or between any two paths in the circuit.

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SIST EN IEC 60633:2020
– 8 – IEC 60633:2019 © IEC 2019
5.6.1
line commutation

method of commutation whereby the commutating voltage is supplied by the AC system

5.7
commutating group

group of converter arms which commutate cyclically and independently from other converter

arms and where the commutations are normally not simultaneous

Note 1 to entry: In the case of a bridge, a commutating group is composed of the converter arms connected to a

common DC terminal. In certain cases, e.g. when large currents and/or large commutation inductances are

involved, the commutation in the two commutating groups belonging to the same bridge need not be independent.

SEE: Figure 2.
5.8
commutation inductance

total inductance included in the commutation circuit, in series with the commutating voltage

5.9
pulse number

characteristic of a converter connection expressed as the number of non-simultaneous

symmetrical commutations occurring during one cycle of the AC line voltage

Note 1 to entry: The pulse number of a bridge converter connection defined in 5.3 is always p = 6.

5.10
commutation number
number of commutations during one cycle of the AC line voltage occurring in each
commutating group

Note 1 to entry: In a bridge converter connection, each commutating group has a commutation number q = 3.

5.11
capacitor commutated converter

converter in which series capacitors are included between the converter transformer and the

valves
SEE: Figure 13 a).
5.12
controlled series capacitor converter

converter in which series capacitors are inserted between the AC filter bus and the AC

network
SEE: Figure 13 b).
5.13
commutating voltage
voltage which causes the current to commutate
[SOURCE: IEC 60050-551:1998, 551-16-02]
5.14
controlled capacitor commutated converter

converter in which controlled series capacitors are included between the converter

transformer and the valves
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SIST EN IEC 60633:2020
IEC 60633:2019 © IEC 2019 – 9 –
5.15
series capacitor converter

converter in which fixed series capacitors are inserted between the AC filter bus and the AC

network
6 Converter units and valves
6.1
converter unit

indivisible operative unit comprising all equipment between the point of common coupling on

the AC side (see 8.24) and the point of common coupling-DC side (see 8.25), essentially one

or more converter bridges, together with one or more converter transformers, converter unit

control equipment, essential protective and switching devices and auxiliaries, if any, used for

conversion
SEE: Figure 3.
6.2
converter bridge

equipment used to implement the bridge converter connection and the by-pass arm, if used

Note 1 to entry: The term "bridge" may be used to describe either the circuit connection or the equipment

implementing that circuit (see 5.3).
6.2.1
anode/cathode valve commutating group

equipment used to implement the converter arms of one commutating group of a bridge with

interconnected anode/cathode terminals
6.3
valve

complete operative controllable or non-controllable valve device assembly, normally

conducting in only one direction (the forward direction), which can function as a converter arm

in a converter bridge
6.3.1
single valve unit
single structure comprising only one valve
6.3.2
multiple valve unit
MVU
single structure comprising more than one valve

Note 1 to entry: Examples of multiple valve units are double valves, quadrivalves and octovalves with two, four

and eight series-connected valves respectively.
Note 2 to entry: This note applies to the French language only.
6.4
main valve
valve in a converter arm
6.5
by-pass valve
valve in a by-pass arm
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SIST EN IEC 60633:2020
– 10 – IEC 60633:2019 © IEC 2019
6.6
thyristor module

part of a valve comprising a mechanical assembly of thyristors with their immediate auxiliaries

but without valve reactors

Note 1 to entry: Thyristor modules may be elements in the construction of a valve, and/or be interchangeable for

maintenance purposes.
6.7
reactor module

part of a valve, being a mechanical assembly of one or more reactors, used in some valve

designs
Note 1 to entry: Reactor modules may be elements in the construction of a valve.
6.8
valve section

electrical assembly, comprising a number of thyristors and other components, which exhibits

prorated electrical properties of a complete valve

Note 1 to entry: This term is mainly used to define a test object for valve testing purposes.

6.9
valve thyristor level

part of a valve comprising a thyristor, or thyristors connected in parallel, together with their

immediate auxiliaries, and reactor, if any
6.10
valve support

part of the valve which mechanically supports and electrically insulates the active part of the

valve from earth

Note 1 to entry: 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.
6.11
valve structure

structural components of a valve, required in order to physically support the valve modules

6.12
valve base electronics
VBE

electronic unit, at earth potential, providing the electrical to optical conversion between the

converter control system and the valves
Note 1 to entry: This note applies to the French language only.
6.13
valve electronics

electronic circuits at valve potential(s) which perform control and protection functions for one

or more thyristor levels
6.14
valve arrester
arrester connected across a valve
SEE: Figure 3.
6.15
converter unit arrester
arrester connected across the DC terminals of a converter unit
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SIST EN IEC 60633:2020
IEC 60633:2019 © IEC 2019 – 11 –
SEE: Figure 3.
6.16
converter unit DC bus arrester

arrester connected from the high-voltage DC bus of the converter unit to substation earth

SEE: Figure 3 and Figure 7.
6.17
midpoint DC bus arrester

arrester connected between the midpoint of the two 6-pulse bridges of a 12-pulse converter

unit and substation earth

Note 1 to entry: In some HVDC substation designs, two twelve-pulse converter units are connected in series. In

this case, the midpoint DC bus arrester at the upper twelve-pulse converter unit is not connected to the substation

earth but to the high-voltage DC bus of the lower twelve-pulse converter unit.
SEE: Figure 7.
6.18
valve reactor

reactor(s) connected in series with the thyristors in a valve, for the purpose of limiting the rate

of rise of current at turn-on and voltage during the off-state

Note 1 to entry: Valve reactors may be external to the entire valve or distributed within the valve.

6.19
converter transformer

transformer through which energy is transmitted from an AC system to one or more converter

bridges or vice versa
SEE: Figure 3.
6.19.1
line side windings
converter transformer windings which are connected to the AC system
6.19.2
valve side windings

converter transformer windings which are connected to the AC terminals of one or more

converter bridges
6.20
valve module

part of a valve comprising a mechanical assembly of thyristors with their immediate auxiliaries

and valve reactor(s)
6.21
redundant levels

maximum number of series connected thyristor 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
6.22
valve anode terminal
valve terminal at which the forward current flows into the valve
6.23
valve cathode terminal
valve terminal at which the forward current flows out of the valve
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SIST EN IEC 60633:2020
– 12 – IEC 60633:2019 © IEC 2019
7 Converter operating conditions
7.1
rectifier operation
rectification

mode of operation of a converter or an HVDC substation when energy is transferred from the

AC side to the DC side
7.2
inverter operation
inversion

mode of operation of a converter or an HVDC substation when energy is transferred from the

DC side to the AC side
7.3
forward direction
conducting direction
direction in which a valve is capable of conducting load current
7.4
reverse direction
non-conducting direction
reverse of the conducting direction
7.5
forward current
current which flows through a valve in the forward direction
7.6
reverse current
current which flows through a valve in the reverse direction
7.7
forward voltage

voltage applied between the anode and cathode terminals of a valve or an arm when the

anode is positive with respect to the cathode
7.8
reverse voltage

voltage applied between the anode and cathode terminals of a valve or an arm when the

anode is negative with respect to the cathode
7.9
conducting state
on-state
condition of a valve when the valve exhibits a low resistance
Note 1 to entry: The valve voltage for this condition is shown in Figure 6.
7.10
valve voltage drop
...

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