SIST EN IEC 61869-14:2019

SLOVENSKI STANDARD
SIST EN IEC 61869-14:2019
01-oktober-2019
Instrumentni transformatorji - 14. del: Dodatne zahteve za tokovne transformatorje
za enosmerno napajanje (IEC 61869-14:2018)
Instrument transformers - Part 14: Additional requirements for current transformers for
DC applications (IEC 61869-14:2018)
Messwandler - Teil 14: Besondere Anforderungen für Gleichstromwandler (IEC 61869-
14:2018)
Transformateurs de mesure - Partie 14: Exigences supplémentaires concernant les
transformateurs de courant pour application en courant continu (IEC 61869-14:2018)
Ta slovenski standard je istoveten z: EN IEC 61869-14:2019
ICS:
17.220.20 Merjenje električnih in Measurement of electrical
magnetnih veličin and magnetic quantities
SIST EN IEC 61869-14:2019 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN IEC 61869-14:2019


EUROPEAN STANDARD EN IEC 61869-14

NORME EUROPÉENNE

EUROPÄISCHE NORM
July 2019
ICS 17.200.20

English Version
Instrument transformers - Part 14: Additional requirements for
current transformers for DC applications
(IEC 61869-14:2018)
Transformateurs de mesure - Partie 14: Exigences Messwandler - Teil 14: Besondere Anforderungen für
supplémentaires concernant les transformateurs de courant Gleichstromwandler
pour application en courant continu (IEC 61869-14:2018)
(IEC 61869-14:2018)
This European Standard was approved by CENELEC on 2018-08-21. 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 61869-14:2019 E

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SIST EN IEC 61869-14:2019
EN IEC 61869-14:2019 (E)
European foreword
The text of document 38/560/FDIS, future edition 1 of IEC 61869-14, prepared by IEC/TC 38
"Instrument transformers" was submitted to the IEC-CENELEC parallel vote and approved by
CENELEC as EN IEC 61869-14:2019.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2020-01-05
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2022-07-05
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.
This document has been prepared under a mandate given to CENELEC by the European
Commission and the European Free Trade Association, and supports essential requirements of EU
Directive(s).
For the relationship with EU Directive(s) see informative Annex ZZ, which is an integral part of this
document.
Endorsement notice
The text of the International Standard IEC 61869-14:2018 was approved by CENELEC as a European
Standard without any modification.


2

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EN IEC 61869-14:2019 (E)
Annex ZA
(normative)

Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
NOTE 1  Where an International Publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
NOTE 2  Up-to-date information on the latest versions of the European Standards listed in this annex is available here:
www.cenelec.eu.
Clause 2 of IEC 61869-6:2016 is applicable, with the following additions and modifications:
Publication Year Title EN/HD Year
IEC/TS 60815-4 2019 Selection and dimensioning of high-voltage - -
insulators intended for use in polluted
conditions - Part 4: Insulators for d.c.
systems
IEC/TS 61245:2015 2015 Artificial pollution tests on high-voltage - -
ceramic and glass insulators to be used on
d.c. systems
IEC 61869-6 2016 Instrument transformers - Part 6: Additional EN 61869-6 2016
general requirements for low-power
instrument transformers
IEC 61869-9 2016 Instrument transformers - Part 9: Digital EN IEC 61869-9 2019
interface for instrument transformers




3

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IEC 61869-14

®


Edition 1.0 2018-07




INTERNATIONAL



STANDARD




NORME



INTERNATIONALE
colour

inside










Instrument transformers –

Part 14: Additional requirements for current transformers for DC applications




Transformateurs de mesure –

Partie 14: Exigences supplémentaires concernant les transformateurs de

courant pour application en courant continu















INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE


INTERNATIONALE




ICS 17.220.20 ISBN 978-2-8322-5803-3




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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CONTENTS
FOREWORD . 4
INTRODUCTION . 7
1 Scope . 11
2 Normative references . 11
3 Terms and definitions . 11
5 Ratings . 16
6 Design and construction . 20
7 Tests . 25
Annex 14A (informative) Equivalent thermal current in CTs for DC application . 37
14A.1 General . 37
14A.2 Current harmonic content . 37
14A.3 Losses in primary conductor due to harmonic content . 38
14A.4 Thermal test with AC current . 40
Annex 14B (informative) Proposed rated insulation level applicable to current
transformers for DC application. 41
Bibliography . 42

Figure 1401 – Example of LCC scheme . 7
Figure 1402 – Typical scheme for VSC – symmetrical monopole . 8
Figure 1403 – Typical scheme for VSC – asymmetrical monopole or bipole . 9
Figure 1404 – Typical step responses of a system . 14
Figure 1405 – Accuracy limits of a DCCT . 19
Figure 1406 – Polarity reversal test profile . 30
Figure 1407 – Measurement of the step response time . 32
Figure 14A.1 – Typical waveform of current flowing in the primary conductor for LCC
applications . 37
Figure 14A.2 – The two terms that make up the total losses in the primary conductor . 39
Figure 14A.3 – Additional losses in conductors due to typical current harmonics . 40
Figure 14A.4 – Power-frequency losses in conductors compared to DC losses . 40

Table 1401 – Current and voltage in current transformers for LCC application . 8
Table 1402 – Current and voltage in current transformers for VSC application . 10
Table 3 – Partial discharge test voltages and permissible levels . 17
Table 1403 – Limits of ratio error for DCCT (classes from 0,1 to 1) . 19
Table 7 – Static withstand test loads . 21
Table 8 – Arc fault duration and performance criteria . 22
Table 1404 – Markings of terminals . 23
Table 1405 – Rating plate marking for common rating plate . 24
Table 1406 – Rating plate marking for each secondary converter . 24
Table 1407 – Rating plate marking for auxiliary power supply . 25

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Table 10 – List of tests. 26
Table 14A.1 – Typical harmonic current values (800 kV LCC) . 38
Table 14B.1 – Proposed rated primary terminal insulation levels for current
transformers for DC application. 41

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INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

INSTRUMENT TRANSFORMERS –

Part 14: Additional requirements for current
transformers for DC applications

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 61869-14 has been prepared by IEC technical committee 38:
Instrument transformers.
The text of this standard is based on the following documents:
FDIS Report on voting
38/560/FDIS 38/565/RVD

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.

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IEC 61869-14:2018 © IEC 2018 – 5 –
A list of all parts in the IEC 61869 series, published under the general title Instrument
transformers, can be found on the IEC website.
This Part 14 is to be used in conjunction with, and is based on, IEC 61869-1:2007, General
requirements, and IEC 61869-6:2016, Additional general requirements for low-power
instrument transformers – however the reader is encouraged to use the most recent editions.
This Part 14 follows the structure of IEC 61869-1:2007 and IEC 61869-6:2016 and
supplements or modifies their corresponding clauses.
When a subclause of Part 1 or Part 6 is not mentioned in this Part 14, that subclause applies.
When this standard states “addition”, “modification” or “replacement”, the relevant text in
Part 1 or Part 6 is to be adapted accordingly.
For additional clauses, subclauses, figures, tables, annexes or notes, the following numbering
system is used:
• clauses, subclauses, tables, figures and notes that are numbered starting from 1401 are
additional to those in Part 1 and Part 6;
• additional annexes are lettered 14A, 14B, etc.
An overview of the planned set of standards at the date of publication of this document is
given below. The updated list of standards issued by IEC TC 38 is available at the website:
www.iec.ch
PRODUCT FAMILY STANDARDS PRODUCT PRODUCTS OLD
STANDARD STANDARD
61869-1 61869-2 ADDITIONAL REQUIREMENTS FOR 60044-1
CURRENT TRANSFORMERS 60044-6
GENERAL
REQUIREMENTS
61869-3 ADDITIONAL REQUIREMENTS FOR 60044-2
INDUCTIVE VOLTAGE TRANSFORMERS
61869-4 ADDITIONAL REQUIREMENTS FOR 60044-3
COMBINED TRANSFORMERS
61869-5 ADDITIONAL REQUIREMENTS FOR 60044-5
CAPACITIVE VOLTAGE TRANSFORMERS
ADDITIONAL REQUIREMENTS FOR
61869-6 61869-7 60044-7
ELECTRONIC VOLTAGE TRANSFORMERS
ADDITIONAL
GENERAL 61869-8 ADDITIONAL REQUIREMENTS FOR 60044-8
REQUIREMENTS
ELECTRONIC CURRENT
FOR LOW-POWER
TRANSFORMERS
INSTRUMENT
DIGITAL INTERFACE FOR INSTRUMENT
61869-9
TRANSFORMERS
TRANSFORMERS
61869-10 ADDITIONAL REQUIREMENTS FOR LOW-
POWER PASSIVE CURRENT
TRANSFORMERS
61869-11 ADDITIONAL REQUIREMENTS FOR LOW- 60044-7
POWER PASSIVE VOLTAGE
TRANSFORMERS
61869-12 ADDITIONAL REQUIREMENTS FOR
COMBINED ELECTRONIC INSTRUMENT
TRANSFORMER OR COMBINED LOW-
POWER PASSIVE TRANSFORMERS
61869-13 STAND ALONE MERGING UNIT
ADDITIONAL REQUIREMENTS FOR
61869-14
CURRENT TRANSFORMERS FOR DC
APPLICATIONS
61869-15 ADDITIONAL REQUIREMENTS FOR
VOLTAGE TRANSFORMERS FOR DC
APPLICATIONS

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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.

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 document using a
colour printer.

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INTRODUCTION
General
This document applies to current transformers intended to be used in DC applications with at
least one of the following functions:
• measure DC current (with significant harmonics);
• withstand DC voltage.
Depending on the position of the current transformer on the DC system, different kinds of
application exist, which are briefly described below, together with the approximate voltage or
current wave shape.
Line-commutated converters (LCC)
Line-commutated converters (LCC) are based on thyristor converters (see Figure 1401). They
are characterized by a single direction of current flow, and a voltage polarity reversal
possibility. Significant voltage and current harmonics exist up to frequencies of about 3 kHz to
4 kHz.

Figure 1401 – Example of LCC scheme
We distinguish three different current-measurement functions:
• CT1: measurement of the current at the AC side of the converter;
• CT2: measurement of the current at the DC side of the converter;
• CT3: measurement of the current in the DC filter.
Table 1401 gives an overview of the current and voltage waveshapes as well as the main
characteristics of the different applications of the CT.

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Table 1401 – Current and voltage in current transformers for LCC application
Current Voltage Characteristics
CT1 AC current
AC + DC voltage
Large amount of current harmonics
Mainly for protection purposes


CT2 Pure DC application
High-accuracy measurement
Harmonics measurement
Metering, control and protection
purposes


CT3 DC voltage stress with harmonics
DC current = 0
Harmonics measurement
Mainly for protection purposes



Voltage-source converters (VSC)
Voltage-source converters (VSC) are based on transistor converters. They are characterized
by a bi-directional current flow and a single voltage polarity. Voltage and current harmonics
exist up to frequencies of about 20 kHz.
Two variants of VSC schemes exist: symmetrical monopoles (using one single converter) and
asymmetrical monopole or bipole (with one converter for each polarity).
Both schemes are shown in Figure 1402 and Figure 1403.

Figure 1402 – Typical scheme for VSC – symmetrical monopole

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Figure 1403 – Typical scheme for VSC – asymmetrical monopole or bipole
We distinguish three different current-measurement functions:
• CT4: measurement of the current in the transistor branches of the converter.
The CT can be placed before (CT4a) or after the transistor branch (CT4b);
• CT2: measurement of the current at the DC side of the converter;
• CT3: measurement of the current in the DC filter (not always present in this scheme).
Table 1402 gives an overview of the current and voltage waveshapes as well as the main
characteristics of the different applications of the CT.

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Table 1402 – Current and voltage in current transformers for VSC application
Current Voltage Characteristics
CT2 Pure DC application
High accuracy
measurement
Harmonics measurement
Metering, control and
protection purposes
Short step response time


CT3 DC voltage stress
DC current = 0
Harmonics measurement
Mainly for protection
purposes


CT4a Symmetrical monopole: Pure AC voltage or DC +
AC voltage
DC + AC current
High-accuracy
measurement
Short step response time


Asymmetrical monopoles /
bipoles:

CT4b DC voltage stress
DC + AC current
High-accuracy
measurement
Short step response time

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INSTRUMENT TRANSFORMERS –

Part 14: Additional requirements for current
transformers for DC applications



1 Scope
This part of IEC 61869 provides all requirements specific to current transformers to be used in
DC applications (DCCTs), whatever the technology used. The output signal can be analogue
or digital.
It is applicable to newly manufactured current transformers used for measuring, protection
and/or control applications in DC power systems with a rated voltage above 1,5 kV.
The general configuration of a single-pole low-power instrument transformer is described in
Figure 601 of IEC 61869-6:2016.
The DCCTs intended for current measurement in the transistor branch of the VSC valve
(referred to as CT4a and CT4b in Figure 1403 and Table 1402) are not covered by this
document, and will be considered in a future revision.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements of this document. For dated references, only the edition
cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
Clause 2 of IEC 61869-6:2016 is applicable, with the following additions and modifications:
IEC TS 60815-4:2016, Selection and dimensioning of high-voltage insulators intended for use
in polluted conditions – Part 4: Insulators for DC systems
IEC TS 61245:2015, Artificial pollution tests on high-voltage ceramic and glass insulators to
be used on DC systems
IEC 61869-6:2016, Instrument transformers – Part 6: Additional general requirements for low-
power instrument transformers
IEC 61869-9:2016, Instrument transformers – Part 9: Digital interface for instrument
transformers
3 Terms and definitions
Clause 3 of IEC 61869-1:2007, of IEC 61869-6:2016 and of IEC 61869-9:2016 are applicable
with the following additions and modifications.

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3.1 General definitions
3.1.1401
instrument transformer for DC application
instrument transformer intended to be used in DC applications with at least one of the
following functions:
• measure DC current or DC voltage (with significant harmonics);
• withstand DC voltage.
3.1.1402
current transformer for DC application
DCCT
instrument transformer for DC application in which the secondary signal, under normal
conditions of use, is substantially proportional to the primary current
Note 1 to entry: The different applications are described in the introduction.
3.2 Definitions related to dielectric ratings
3.2.2
highest voltage for equipment
U
m
Definition 3.2.2 of IEC 61869-1:2007 is replaced by the following one:
highest value of DC voltage for which the equipment is designed to operate continuously, in
respect of its insulation as well as other characteristics that relate to this voltage
3.3 Definitions related to current ratings
3.3.1401
DC overload current
overcurrent occurring in an electric circuit, which is not caused by a short-circuit or an earth
fault
Note 1 to entry: The DC overload current is specified by the customer in terms of value and duration.
[SOURCE: IEC 60050-826:2004, 826-11-15, modified – “DC” added in the term and Note 1 to
entry added.]
3.3.1402
short-time overload current
I
sov
DC overload current occurring for a duration shorter than one minute
3.3.1403
long-time overload current
I
lov
DC overload current occurring for a duration of minutes or hours
Note 1 to entry: Different values of long-time overload can be specified for different durations.
3.3.1404
maximum peak fault current
I
sc
maximum peak value of current occurring during a fault condition of the DC power system

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3.4 Definitions related to accuracy
3.4.1401
Absolute error
ε
A
error (expressed in A) that a current transformer introduces into the measurement and which
arises from the fact that the actual transformation ratio is not equal to the rated transformation
ratio
Note 1 to entry: The absolute error is defined by the following formula:

ε = K ⋅ U – I
A r s p
where
K is the rated transformation ratio;
r
I is the DC value of the actual primary current in steady state;
p
U is the DC value of the output voltage.
s
3.5 Definitions related to other ratings
3.5.1401
step response
duration between the instant when the measurand (or quantity supplied) is subjected to a
specified abrupt change and the instant when the indication (or quantity supplied) reaches,
and remains within specified limits of, its final steady-state value
Note 1 to entry: See graphical explanation in Figure 1404.

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a
 For periodic behaviour
b
 For aperiodic behaviour
u Input variable
U Initial value of the input variable
0
U Step height of the input variable
s
v Output variable
V , V Steady-state values before and after application of the step
0 ∞
v Overshoot
m
Specified tolerance limit
2 ∆v
s
T Step response time
sr
T Settling time
s
T Dead time
t
Figure 1404 – Typical step responses of a system
Note 2 to entry: The dead time includes the delay time.
[SOURCE: IEC 60050-311:2001, 311-06-04 and IEC 60050-351:2013, 351-45-27 modified –
Note 1 to entry has been added; the notes of the sources have been deleted.]

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3.5.1402
step response time
T
sr
for a step response, the duration of the time interval between the instant of the step change of
an input variable and the instant when the output variable reaches for the first time a specified
percentage of the difference between the final and the initial steady-state values
Note 1 to entry: The step response time includes the delay time of the current transformer.
[SOURCE: IEC 60050-351:2013, 351-45-36, modified – Note 1 to entry has been modified
and the figure has been deleted.]
3.5.1403
settling time
T
s
for a step response, the duration of the time interval between the instant of the step change of
an input variable and the instant when the
...