EN 62751-2:2014/A2:2023

SLOVENSKI STANDARD
01-april-2024
Izgubne moči v napetostnih pretvorniških ventilih za visokonapetostne enosmerne
sisteme - 2. del: Modularni večnivojski pretvorniki - Dopolnilo A2 (IEC 62751-
2:2014/AMD2:2023)
Power losses in voltage sourced converter (VSC) valves for high-voltage direct current
(HVDC) systems - Part 2: Modular multilevel converters
(IEC 62751-2:2014/AMD2:2023)
Bestimmung der Leistungsverluste in Spannungszwischenkreis-Stromrichtern (VSC) für
Hochspannungsgleichstrom(HGÜ)-Systeme - Teil 2: Modulare Mehrpunkt-Stromrichter
(IEC 62751-2:2014/AMD2:2023)
Pertes de puissance dans les valves à convertisseur de source de tension (VSC) des
systèmes en courant continu à haute tension (CCHT) - Partie 2: Convertisseurs
multiniveaux modulaires (IEC 62751-2:2014/AMD2:2023)
Ta slovenski standard je istoveten z: EN 62751-2:2014/A2:2023
ICS:
29.200 Usmerniki. Pretvorniki. Rectifiers. Convertors.
Stabilizirano električno Stabilized power supply
napajanje
29.240.01 Omrežja za prenos in Power transmission and
distribucijo električne energije distribution networks in
na splošno general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 62751-2:2014/A2

NORME EUROPÉENNE
EUROPÄISCHE NORM October 2023
ICS 29.200; 29.240.99
English Version
Power losses in voltage sourced converter (VSC) valves for
high-voltage direct current (HVDC) systems - Part 2: Modular
multilevel converters
(IEC 62751-2:2014/AMD2:2023)
Pertes de puissance dans les valves à convertisseur de Bestimmung der Leistungsverluste in
source de tension (VSC) des systèmes en courant continu Spannungszwischenkreis-Stromrichtern (VSC) für
à haute tension (CCHT) - Partie 2: Convertisseurs Hochspannungsgleichstrom(HGÜ)-Systeme - Teil 2:
multiniveaux modulaires Modulare Mehrpunkt-Stromrichter
(IEC 62751-2:2014/AMD2:2023) (IEC 62751-2:2014/AMD2:2023)
This amendment A2 modifies the European Standard EN 62751-2:2014; it was approved by CENELEC on 2023-10-02. CENELEC
members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this amendment 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 amendment exists in three official versions (English, French, German). A version in any other language made by translation under the
responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the same status as
the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 62751-2:2014/A2:2023 E

European foreword
The text of document 22F/712/CDV, future IEC 62751-2/AMD2, 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 62751-2:2014/A2:2023.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2024-07-02
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2026-10-02
document have to be withdrawn
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 62751-2:2014/AMD2:2023 was approved by CENELEC as
a European Standard without any modification.

IEC 62751-2 ®
Edition 1.0 2023-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
AMENDMENT 2
AMENDEMENT 2
Power losses in voltage sourced converter (VSC) valves for high-voltage direct

current (HVDC) systems –
Part 2: Modular multilevel converters

Pertes de puissance dans les valves à convertisseur de source de tension (VSC)

des systèmes en courant continu à haute tension (CCHT) –

Partie 2: Convertisseurs multiniveaux modulaires

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.200, 29.240.99 ISBN 978-2-8322-7446-0

– 2 – IEC 62751-2:2014/AMD2:2023
© IEC 2023
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
POWER LOSSES IN VOLTAGE SOURCED
CONVERTER (VSC) VALVES FOR HIGH-VOLTAGE
DIRECT CURRENT (HVDC) SYSTEMS –

Part 2: Modular multilevel converters

AMENDMENT 2
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 document may be the subject of patent
rights. IEC shall not be held responsible for identifying any or all such patent rights.
Amendment 2 to IEC 62751-2:2014 has been prepared by subcommittee 22F: Power
electronics for electrical transmission and distribution systems, of IEC technical committee 22:
Power electronic systems and equipment.
The text of this Amendment is based on the following documents:
Draft Report on voting
22F/712/CDV 22F/726/RVC
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this Amendment is English.

IEC 62751-2:2014/AMD2:2023 – 3 –
© IEC 2023
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications/.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
___________
3.1.11
no-load operating state
Add, to the end of the existing Note 1 to entry, added by IEC 62751-2/AMD1:2019, the following
sentence:
The integration time over which such losses are averaged might need to be longer than during normal operation, so
as to obtain the correct weighted average of the losses while blocked and the losses while switching.
4.2 Principles for loss determination
Replace, in the last sentence of the existing first paragraph, modified by
IEC 62751-2/AMD1:2019, the word "justify" with "explain".
Replace, in the last sentence of the existing third paragraph, modified by
IEC 62751-2/AMD1:2019, the text "is now under study in CIGRÉ WG B4-75" with "has been
studied by CIGRE WG B4-75 and is summarised in Annex C".
Delete the third sentence of the existing last paragraph, starting with "Care should also be
taken".
4.4 Loss calculation method
Delete, in the third sentence of the existing first paragraph, the words "for example valve
currents and switching energies".
Replace, in the last sentence of the existing second paragraph, the word "currents" with
"losses".
Delete, in the existing last paragraph, the words "and justified".
Add, to the end of the existing last paragraph, the following new sentence:
The main benefit of the numerical offline simulation is the determination of the average
distribution of the switching events across a cycle.

– 4 – IEC 62751-2:2014/AMD2:2023
© IEC 2023
Add, after the existing last paragraph, the following new paragraph:
The remaining calculations can be performed analytically with a reasonable accuracy. If it can
be shown by the manufacturer that the distribution of switching events is reasonably accurate,
then the remaining calculations shall be allowed to be performed analytically.
4.5.2 Input data for numerical simulations
Replace, in the existing dashed list, modified by IEC 62751-2/AMD1:2019, the first dashed item
with the following new item:
The simulation model shall include a control block which reproduces the correct valve current
and switching pattern used in the complete system.
Delete, in the fourth dash of the existing dashed list, modified by IEC 62751-2/AMD1:2019, the
words "parasitic elements".
Replace, in the fifth dash of the existing dashed list, modified by IEC 62751-2/AMD1:2019, the
text "with a reduced number of" with "using a lumped representation of the".
Delete the last two dashed items of the existing dashed list, modified by
IEC 62751-2/AMD1:2019.
Add, after the existing dashed list, modified by IEC 62751-2/AMD1:2019, the following new
paragraph and list:
There are two different approaches/methods which may be applied:
1) Two-stage simulation and calculation method on the basis of simulated input values
In this approach, the input parameters required for a calculation shall be simulated using a
model which at least represents the on-state characteristics of the converter as well as the
switching pattern or control pattern for the switching of the cells. The on-state representation
may be chosen on the basis of worst-case characteristics (at high junction temperatures) or
on-state characteristics for lower junction temperatures. The simulated values (voltages,
currents and switching pattern) shall be used as input for the calculations. For the
calculations with the simulated values, the following two approaches may be used.
a) The semiconductor parameters are chosen for the rated or worst-case junction
temperature condition and the losses shall be calculated on the basis of the rated
junction temperature.
NOTE Due to the assumption of a worst-case temperature condition, this calculation will result in higher
losses than what can actually be observed in the real application.
b) Using a thermal model, the temperature-depen
...