EN 62475:2010

SLOVENSKI STANDARD
01-februar-2011
Visokotokovne preskusne tehnike - Definicije in zahteve za preskusne toke in
merilne sisteme (IEC 62475:2010)
High-current test techniques - Definitions and requirements for test currents and
measuring systems (IEC 62475:2010)
Hochstrom-Prüftechnik - Begriffe und Anforderungen für Hochstrom-Messungen (IEC
62475:2010)
Techniques des essais à haute intensité - Définitions et exigences relatives aux courants
d'essai et systèmes de mesure (CEI 62475:2010)
Ta slovenski standard je istoveten z: EN 62475:2010
ICS:
19.080 (OHNWULþQRLQHOHNWURQVNR Electrical and electronic
SUHVNXãDQMH testing
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 62475
NORME EUROPÉENNE
December 2010
EUROPÄISCHE NORM
ICS 19.080
English version
High-current test techniques -
Definitions and requirements for test currents and measuring systems
(IEC 62475:2010)
Techniques des essais à haute intensité - Hochstrom-Prüftechnik -
Définitions et exigences relatives aux Begriffe und Anforderungen für
courants d'essai et systèmes de mesure Hochstrom-Messungen
(CEI 62475:2010) (IEC 62475:2010)

This European Standard was approved by CENELEC on 2010-12-01. 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 Central Secretariat 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 Central Secretariat 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, Romania, Slovakia, Slovenia,
Spain, Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Management Centre: Avenue Marnix 17, B - 1000 Brussels

© 2010 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 62475:2010 E
Foreword
The text of document 42/278/FDIS, future edition 1 of IEC 62475, prepared by IEC TC 42, High-voltage
testing techniques, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as
EN 62475 on 2010-12-01.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN and CENELEC shall not be held responsible for identifying any or all such patent
rights.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
(dop) 2011-09-01
national standard or by endorsement
– latest date by which the national standards conflicting
(dow) 2013-12-01
with the EN have to be withdrawn
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 62475:2010 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 60076-5:2000 NOTE  Harmonized as EN 60076-5:2000 (not modified).
IEC 60099-4:2004 NOTE  Harmonized as EN 60099-4:2004 (modified).
IEC 60265-1:1998 NOTE  Harmonized as EN 60265-1:1998 (not modified).
IEC 60282-1:2009 NOTE  Harmonized as EN 60282-1:2009 (not modified).
IEC 60947-1:2007 NOTE  Harmonized as EN 60947-1:2007 (not modified).
IEC 60947-2:2006 NOTE  Harmonized as EN 60947-2:2006 (not modified).
IEC 60947-3:2008 NOTE  Harmonized as EN 60947-3:2009 (not modified).
IEC 61000-4-5 NOTE  Harmonized as EN 61000-4-5.
IEC 61083-1:2001 NOTE  Harmonized as EN 61083-1:2001 (not modified).
IEC 61083-2:1996 NOTE  Harmonized as EN 61083-2:1997 (not modified).
IEC 61180-2:1994 NOTE  Harmonized as EN 61180-2:1994 (not modified).
IEC 61230:2008 NOTE  Harmonized as EN 61230:2008 (not modified).
IEC 61643-11 NOTE  Harmonized as EN 61643-11.
IEC 61643-21 NOTE  Harmonized as EN 61643-21.
IEC 62271-1 NOTE  Harmonized as EN 62271-1.
IEC 62271-100:2008 NOTE  Harmonized as EN 62271-100:2009 (not modified).
IEC 62271-101 NOTE  Harmonized as EN 62271-101.
IEC 62271-102:2001 NOTE  Harmonized as EN 62271-102:2002 (not modified).

- 3 - EN 62475:2010
IEC 62271-103 NOTE  Harmonized as EN 62271-103.
IEC 62271-104 NOTE  Harmonized as EN 62271-104.
IEC 62271-105 NOTE  Harmonized as EN 62271-105.
IEC 62271-110:2009 NOTE  Harmonized as EN 62271-110:2009 (not modified).
IEC 62305-1 NOTE  Harmonized as EN 62305-1.
ISO/IEC 17025:2005 NOTE  Harmonized as EN ISO/IEC 17025:2005 (not modified).
__________
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

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.

NOTE  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
Publication Year Title EN/HD Year

IEC 60051-2 1984 Direct acting indicating analogue electrical EN 60051-2 1989
measuring instruments and their accessories -
Part 2: Special requirements for ammeters
and voltmeters
IEC 60060-1 2010 High-voltage test techniques - EN 60060-1 2010
Part 1: General definitions and test
requirements
IEC 61180-1 - High-voltage test techniques for low-voltage EN 61180-1 -
equipment -
Part 1: Definitions, test and procedure
requirements
ISO/IEC Guide 98-3 2008 Uncertainty of measurement - - -
Part 3: Guide to the expression of uncertainty
in measurement (GUM:1995)
IEC 62475 ®
Edition 1.0 2010-09
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
High-current test techniques – Definitions and requirements for test currents
and measuring systems
Techniques des essais à haute intensité – Définitions et exigences relatives
aux courants d'essai et systèmes de mesure

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
XE
CODE PRIX
ICS 19.080 ISBN 978-2-88912-184-7
– 2 – 62475 © IEC:2010
CONTENTS
FOREWORD.8
1 Scope.10
2 Normative references .10
3 Terms and definitions .10
3.1 Measuring systems.11
3.2 Components of a measuring system .11
3.3 Scale factors .12
3.4 Rated values .13
3.5 Definitions related to the dynamic behaviour .13
3.6 Definitions related to uncertainty .14
3.7 Definitions related to tests on measuring systems .16
4 Procedures for qualification and use of a measuring system.17
4.1 General principles .17
4.2 Schedule of performance tests .17
4.3 Schedule of performance checks.17
4.4 Requirements for the record of performance.18
4.4.1 Contents of the record of performance.18
4.4.2 Exceptions.18
4.5 Operating conditions .18
4.6 Uncertainty.19
5 Tests and test requirements for an approved measuring system.20
5.1 General requirements.20
5.2 Calibration – Determination of the scale factor .20
5.2.1 Calibration of a measuring system by comparison with a reference
measuring system (preferred method) .20
5.2.2 Determination of the scale factor of a measuring system from those
of its components .24
5.3 Linearity test .25
5.3.1 Application .25
5.3.2 Alternative methods in order of suitability .26
5.4 Dynamic behaviour.26
5.5 Short-term stability .27
5.5.1 Method .27
5.5.2 Steady-state current .27
5.5.3 Impulse current and short-time current .28
5.5.4 Periodic impulse current and periodic short-time current.28
5.6 Long-term stability.29
5.7 Ambient temperature effect .29
5.8 Effect of nearby current paths .30
5.9 Software effect .32
5.10 Uncertainty calculation .32
5.10.1 General .32
5.10.2 Uncertainty of calibration .32
5.10.3 Uncertainty of measurement using an approved measuring system .33
5.11 Uncertainty calculation of time-parameter measurements (impulse currents
only).34
5.11.1 General .34

62475 © IEC:2010 – 3 –
5.11.2 Uncertainty of the time-parameter calibration.34
5.11.3 Uncertainty of a time-parameter measurement using an approved
measuring system .35
5.12 Interference test .36
5.12.1 Application .36
5.12.2 Current-converting shunts and current transformers with iron .37
5.12.3 Inductive measuring systems without iron (Rogowski coils) .38
5.13 Withstand tests .38
5.13.1 Voltage withstand tests.38
5.13.2 Current withstand tests.39
6 Steady-state direct current .39
6.1 Application .39
6.2 Terms and definitions .39
6.3 Test current.39
6.3.1 Requirements .39
6.3.2 Tolerances .39
6.4 Measurement of the test current .40
6.4.1 Requirements for an approved measuring system.40
6.4.2 Uncertainty contributions .40
6.4.3 Dynamic behaviour .40
6.4.4 Calibrations and tests on an approved measuring system.40
6.4.5 Performance check.41
6.5 Measurement of ripple amplitude.41
6.5.1 Requirements for an approved measuring system.41
6.5.2 Uncertainty contributions .41
6.5.3 Dynamic behaviour for ripple .41
6.5.4 Calibrations and tests on an approved ripple-current measuring
system.42
6.5.5 Measurement of the scale factor at the ripple frequency .42
6.5.6 Performance check for ripple current measuring system .42
6.6 Test procedures .43
7 Steady-state alternating current.43
7.1 Application .43
7.2 Terms and definitions .43
7.3 Test current.43
7.3.1 Requirements .43
7.3.2 Tolerances .44
7.4 Measurement of the test current .44
7.4.1 Requirements for an approved measuring system.44
7.4.2 Uncertainty contributions .44
7.4.3 Dynamic behaviour .44
7.4.4 Calibrations and tests on an approved measuring system.46
7.4.5 Performance check.47
7.5 Test procedures .47
8 Short-time direct current.47
8.1 Application .47
8.2 Terms and definitions .48
8.3 Test currents .49
8.3.1 Requirements for the test current .49

– 4 – 62475 © IEC:2010
8.3.2 Tolerances .49
8.4 Measurement of the test current .49
8.4.1 Requirements for an approved measuring system.49
8.4.2 Uncertainty contributions .49
8.4.3 Dynamic behaviour .49
8.4.4 Calibrations and tests on an approved measuring system.50
8.4.5 Performance check.51
8.4.6 Linearity test.51
8.5 Test procedures .51
9 Short-time alternating current .51
9.1 Application .51
9.2 Terms and definitions .52
9.3 Test current.53
9.3.1 Requirements for the test current .53
9.3.2 Tolerances .53
9.4 Measurement of the test current .54
9.4.1 Requirements for an approved measuring system.54
9.4.2 Uncertainty contributions .54
9.4.3 Dynamic behaviour .54
9.4.4 Calibrations and tests on an approved measuring system.55
9.4.5 Performance check.56
9.4.6 Linearity test.56
9.4.7 Interference test .57
9.5 Test procedures .57
10 Impulse currents.57
10.1 Application .57
10.2 Terms and definitions .57
10.3 Test current.61
10.3.1 General .61
10.3.2 Tolerances .61
10.4 Measurement of the test current .62
10.4.1 Requirements for an approved measuring system.62
10.4.2 Uncertainty contributions .62
10.4.3 Dynamic behaviour .62
10.4.4 Calibrations and tests on an approved measuring system.64
10.4.5 Performance check.64
10.5 Test procedures .65
11 Current measurement in high-voltage dielectric testing.65
11.1 Application .65
11.2 Terms and definitions .65
11.3 Measurement of the test current .66
11.3.1 Requirements for an approved measuring system.66
11.3.2 Uncertainty contributions .66
11.3.3 Dynamic behaviour .66
11.3.4 Calibrations and tests on an approved measuring system.66
11.3.5 Performance check.67
11.3.6 Linearity test.67
11.3.7 Interference test .67
11.4 Test procedures .67

62475 © IEC:2010 – 5 –
12 Reference measuring systems.67
12.1 General .67
12.2 Interval between subsequent calibrations of reference measuring systems.67
Annex A (informative) Uncertainty of measurement.68
Annex B (informative) Examples of the uncertainty calculation in high-current
measurements .76
Annex C (informative) Step-response measurements.82
Annex D (informative) Convolution method for estimation of dynamic behaviour from
step-response measurements .85
Annex E (informative) Constraints for certain wave shapes.88
Annex F (informative) Temperature rise of measuring resistors.90
Annex G (informative) Determination of r.m.s. values of short-time a.c. current .91
Annex H (informative) Examples of IEC standards with high current tests .98
Bibliography.100

Figure 1 – Examples of amplitude frequency responses for limit frequencies (f ; f ). .14
1 2
Figure 2 – Calibration by comparison over full assigned measurement range.22
Figure 3 – Uncertainty contributions of the calibration (example with the minimum of 5
current levels).23
Figure 4 – Calibration by comparison over a limited current range with a linearity test
(see 5.3) providing extension up to the largest value in the assigned measurement
range .24
Figure 5 – Linearity test of the measuring system with a linear device in the extended
voltage range.26
Figure 6 – Short-term stability test for steady-state current. .28
Figure 7 – Short-term stability test for impulse current and short-time current.28
Figure 8 – Short-term stability test for periodic impulse-current and periodic short-time
current .29
Figure 9 – Test circuit for effect of nearby current path for current-converting shunts
and current transformers with iron. .31
Figure 10 – Test circuit for effect of nearby current path for inductive measuring
systems without iron (Rogowski coils).31
Figure 11 – Principle of interference test circuit. .37
Figure 12 – Interference test on the measuring system i (t) based on
current-converting shunt or current transformer with iron in a typical 3-phase
short-circuit set-up (example). .37
Figure 13 – Test circuit for interference test for inductive systems without iron. .38
Figure 14 – Acceptable normalized amplitude-frequency response of an a.c. measuring
system intended for a single fundamental frequency f .45
nom.
Figure 15 – Acceptable normalized amplitude-frequency response of an a.c. measuring
system intended for a range of fundamental frequencies f to f .46
nom1 nom2
Figure 16 – Example of short-time direct current.48
Figure 17 – Example of short-time alternating current. .52
Figure 18 – Exponential impulse current. .58
Figure 19 – Exponential impulse current – oscillating tail. .58
Figure 20 – Impulse current – Rectangular, smooth. .59

– 6 – 62475 © IEC:2010
Figure 21 – Impulse current – Rectangular with oscillations. .59
Figure A.1 – Normal probability distribution p(x) of a continuous random variable x.75
Figure A.2 – Rectangular symmetric probability distribution p(x) of the estimate x of an
input quantity X.75
Figure B.1 – Comparison between the system under calibration X and the reference
system N .81
Figure C.1 – Circuit to generate current step using a coaxial cable. .82
Figure C.2 – Circuit to generate current step using a capacitor. .82
Figure C.3 – Definition of response parameters with respect to step response.84
Figure E.1 – Attainable combinations of time parameters (shaded area) for the 8/20
impulse at maximum 20 % undershoot and for 20 % tolerance on the time parameters .88
Figure E.2 – Locus for limit of attainable time parameters as a function of permissible
undershoot for the 8/20 impulse.89
Figure E.3 – Locus for limit of attainable time parameters as a function of permissible
undershoot for the 30/80 impulse.89
Figure G.1 – Equivalent circuit of short-circuit test. .91
Figure G.2 – Symmetrical a.c. component of an alternating short-circuit current .92
Figure G.3 – Numerical evaluation of r.m.s value showing both instantaneous current
and instantaneous squared value of the current. .93
Figure G.4 – Three-crest method .94
Figure G.5 – Evaluation of conventional r.m.s. value of an arc current using the three-
crest method.95
Figure G.6 – Evaluation of equivalent r.m.s value of a short-time current during a
short-circuit test.96
Figure G.7 – Relation between peak factor κand power factor cos(ϕ). .97

Table 1 – Required tests for steady-state direct current .40
Table 2 – Required tests for ripple current .42
Table 3 – Required tests for steady-state alternating current .46
Table 4 – Tolerance requirement on test-current parameters for short-time direct
current .49
Table 5 – Required tests for short-time direct current.50
Table 6 – Tolerance requirements on the short-time alternating current test parameters.53
Table 7 – List of typical tests in a high-power laboratory and required minimum
frequency range of the measuring system.54
Table 8 – Tolerance requirements on scale factor.55
Table 9 – Required tests for short-time alternating current.55
Table 10 – Examples of exponential impulse-current types .61
Table 11 – Required tests for impulse current.64
Table 12 – Required tests for impulse current in high-voltage dielectric testing.66
Table A.1 – Coverage factor k for effective degrees of freedom ν (p = 95,45 %) .73
eff
Table A.2 – Schematic of an uncertainty budget .74
Table B.1 – Result of the comparison measurement .78
Table B.2 – Result of the comparison measurement .78
Table B.3 – Uncertainty budget for calibration of scale factor F .79
x
Table B.4 – Result of linearity test .80

62475 © IEC:2010 – 7 –
Table B.5 – Uncertainty budget of scale factor F .81
X,mes
Table H.1 – List of typical tests with short-time alternating current.98
Table H.2 – List of typical tests with exponential impulse current .99
Table H.3 – List of typical tests with rectangular impulse current .99

– 8 – 62475 © IEC:2010
INTERNATIONAL ELECTROTECHNICAL COMMISSION
______________
HIGH-CURRENT TEST TECHNIQUES –
DEFINITIONS AND REQUIREMENTS FOR TEST CURRENTS
AND MEASURING SYSTEMS
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 62475 has been prepared by IEC technical committee 42: High-
voltage test techniques.
The text of this standard is based on the following documents:
FDIS Report on voting
42/278/FDIS 42/283/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

62475 © IEC:2010 – 9 –
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC website under "http://webstore.iec.ch" in the data
related to this 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 document using a
colour printer.
– 10 – 62475 © IEC:2010
HIGH-CURRENT TEST TECHNIQUES –
DEFINITIONS AND REQUIREMENTS FOR TEST CURRENTS
AND MEASURING SYSTEMS
1 Scope
This International Standard is applicable to high-current testing and measurements on both
high-voltage and low-voltage equipment. It deals with steady-state and short-time direct
current (as e.g. encountered in high-power d.c. testing), steady-state and short-time
alternating current (as e.g. encountered in high-power a.c. testing), and impulse-current. In
general, currents above 100 A are considered in this International Standard, although currents
less than this can occur in tests.
NOTE This standard also covers fault detection during, for example, lightning impulse testing.
This standard:
• defines the terms used;
• defines parameters and their tolerances;
• describes methods to estimate uncertainties of high-current measurements;
• states the requirements which a complete measuring system shall meet;
• describes the methods for approving a measuring system and checking its components;
• describes the procedure by which the user shall show that a measuring system meets the
requirements of this standard, including limits set for uncertainty of measurement.
2 Normative references
The following referenced documents are indispensable for the application of this International
Standard. For dated references, only the edition cited applies. For undated references, the
latest edition of the referenced document (including any amendments) applies.
IEC 60051-2:1984, Direct acting analogue electrical measuring instruments and their
accessories – Part 2: Special requirements for ammeters and voltmeters
IEC 60060-1:2010, High-voltage test techniques – Part 1: General definitions and test
requirements
IEC 61180-1, High-voltage test techniques for low-voltage equipment – Part 1: Definitions,
test and procedure requirements
ISO/IEC Guide 98-3:2008, Uncertainty of measurement – Part 3: Guide to the expression of
uncertainty in measurement (GUM: 1995)
NOTE Further related standards, guides, etc. on subjects included in this standard are given in the bibliography.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

62475 © IEC:2010 – 11 –
3.1 Measuring systems
3.1.1
measuring system
complete set of devices suitable for performing measurements of a quantity to be measured
(measurand). Software used to obtain or calculate measurement results also forms a part of
the measuring system
NOTE 1 A high-current measuring system usually comprises the following components:
• converting device with either terminals to connect this device in circuit or appropriate coupling to the circuit,
and connections to earth;
• transmission system(s) connecting the output terminals of the converting device to the measuring
instrument(s) with its attenuating, terminating, and adapting impedances or networks; and
• measuring instrument(s) together with any connections to the power supply.
Measuring systems which comprise only some of the above components or which are based on non-conventional
principles are acceptable if they meet the uncertainty requirements specified in this standard.
NOTE 2 The environment in which a measuring system functions, its clearances to live, current carrying, and
earthed structures, and the presence of electromagnetic fields may significantly affect the measurement result and
its uncertainty.
3.1.2
record of performance
detailed record, established and maintained by the user, describing the measuring system
and containing evidence that the requirements given in this standard have been met. This
evidence includes the results of the initial performance test and the schedule and results of
each subsequent performance test and performance check
3.1.3
approved measuring system
measuring system that is shown to comply with one or more of the sets of requirements set
out in this standard
3.1.4
reference measuring system
measuring system with its calibration traceable to relevant national and/or international
standards, and having sufficient accuracy and stability for use in the approval of other
systems by making simultaneous comparative measurements with specific types of waveform
and ranges of current
NOTE A reference measuring system (maintained according to the requirements of this standard) can be used as
an approved measuring system but the converse is not true.
3.2 Components of a measuring system
3.2.1
converting device
device for converting the quantity to be measured (measurand) into a quantity, compatible
with the measuring instrument
3.2.2
current-converting shunt
resistor across which the voltage is proportional to the current to be measured
3.2.3
current transformer
instrument transformer in which the secondary current, in normal conditions of use, is
substantially proportional to the primary current and differs in phase from it by an angle which
is approximately zero for an appropriate direction of the connections

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