SIST EN 60044-7:2000
(Main)Instrument transformers -- Part 7: Electronic voltage transformers
Instrument transformers -- Part 7: Electronic voltage transformers
Applies to newly manufactured electronic voltage transformers with analogue output, for use with electrical measuring instruments and electrical protective devices at frequencies from 15 Hz to 100 Hz. The standard covers optical arrangements with electronic components. Three-phase voltage transformers are not included, but some of the requirements apply.
Meßwandler -- Teil 7: Elektronische Spannungswandler
Transformateurs de mesure -- Partie 7: Transformateurs de tension électroniques
S'applique aux transformateurs de tension électroniques nouvellement construits, ayant une sortie analogique, et destinés à être utilisés avec des appareils de mesure électriques et des dispositifs éelctriques de protection de fréquence comprise entre 15 Hz et 100 Hz. S'applique aux transformateurs de tension utilisant des configurations optiques avec des composants électroniques. Les transformateurs de tension électroniques triphasés ne sont pas couverts mais certains articles sont applicables.
Instrument transformers - Part 7: Electronic voltage transformers
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-junij-2000
Instrument transformers - Part 7: Electronic voltage transformers
Instrument transformers -- Part 7: Electronic voltage transformers
Meßwandler -- Teil 7: Elektronische Spannungswandler
Transformateurs de mesure -- Partie 7: Transformateurs de tension électroniques
Ta slovenski standard je istoveten z: EN 60044-7:2000
ICS:
17.220.20 0HUMHQMHHOHNWULþQLKLQ Measurement of electrical
PDJQHWQLKYHOLþLQ and magnetic quantities
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD EN 60044-7
NORME EUROPÉENNE
EUROPÄISCHE NORM January 2000
ICS 17.220.20
English version
Instrument transformers
Part 7: Electronic voltage transformers
(IEC 60044-7:1999)
Transformateurs de mesure Meßwandler
Partie 7: Transformateurs de Teil 7: Elektronische Spannungswandler
tension électroniques (IEC 60044-7:1999)
(CEI 60044-7:1999)
This European Standard was approved by CENELEC on 1999-12-01. 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, Czech Republic,
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
CENELEC
© 2000 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
European Committee for Electrotechnical Standardization
Ref. No. EN 60044-7:2000 E
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway,
Portugal, Spain, Sweden, Switzerland and United Kingdom.
Page 2
Foreword
The text of document 38/242/FDIS, future edition 1 of IEC 60044-7, prepared by IEC TC 38,
Instrument transformers, was submitted to the IEC-CENELEC parallel vote and was approved by
CENELEC as EN 60044-7 on 1999-12-01.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2000-10-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2002-12-01
Annexes designated "normative" are part of the body of the standard.
Annexes designated "informative" are given for information only.
In this standard, annexes A and ZA are normative and annexes B and C are informative.
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 60044-7:1999 was approved by CENELEC as a European
Standard without any modification.
__________
Page 3
Annex ZA (normative)
Normative references to international publications
with their corresponding European publications
This European Standard incorporates by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text and the
publications are listed hereafter. For dated references, subsequent amendments to or revisions
of any of these publications apply to this European Standard only when incorporated in it by
amendment or revision. For undated references the latest edition of the publication referred to
applies (including amendments).
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
1)
IEC 60038 (mod) 1983 HD 472 S1 1989
IEC standard voltages
IEC 60044-2 1997 Instrument transformers EN 60044-2 1999
(mod) Part 2: Inductive voltage transformers
IEC 60050-161 1990 International Electrotechnical - -
Vocabulary (IEV)
Chapter 161: Electromagnetic compatibility
IEC 60050-321 1986 Chapter 321: Instrument transformers - -
IEC 60050-601 1985 Chapter 601: Generation, transmission and - -
distribution of electricity - General
IEC 60050-604 1987 Chapter 604: Generation, transmission and - -
distribution of electricity - Operation
IEC 60060-1 1989 High-voltage test techniques HD 588.1 S1 1991
+ corr. March 1990 Part 1: General definitions and test
requirements
IEC 60071-1 1993 Insulation co-ordination EN 60071-1 1995
Part 1: Definitions, principles and rules
)
IEC 60186 (mod) 1987 Voltage transformers 1992
HD 554 S1
IEC 60255-5 1977 Electrical relays - -
Part 5: Insulation tests for electrical relays
IEC 60255-6 1988 Part 6: Measuring relays and protection EN 60255-6 1994
(mod) equipment + corr. February 1995
IEC 60255-11 1979 Part 11: Interruptions to and alternating - -
component (ripple) in d.c. auxiliary energizing
quantity of measuring relays
Page 4
) The title of HD 472 S1 is: Nominal voltages for low-voltage public electricity supply systems.
) HD 554 S1 includes A1:1988 to IEC 60186, mod.
Publication Year Title EN/HD Year
IEC 60255-22-1 1988 Part 22: Electrical disturbance tests for - -
measuring relays and protection equipment
Section 1: 1 MHz burst disturbance tests
IEC 60270 1981 Partial discharge measurements - -
IEC 60617-1 1985 Graphical symbols for diagrams - -
Part 1: General information, general index,
Cross-reference tables
IEC 60694 1996 Common specifications for high-voltage EN 60694 1996
switchgear and controlgear standards + corr. May 1999
IEC 60721 series Classification of environmental conditions EN 60721 series
HD 478 series
IEC 60815 1986 Guide for the selection of insulators in respect - -
of polluted conditions
IEC 61000-4-1 1992 Electromagnetic compatibility (EMC) EN 61000-4-1 1994
Part 4: Testing and measurement techniques
Section 1: Overview of immunity tests
IEC 61000-4-2 1995 Part 4-2: Testing and measurement EN 61000-4-2 1995
techniques - Electrostatic discharge immunity
test
IEC 61000-4-3 1995 Part 4-3: Testing and measurement EN 61000-4-3 1996
(mod) techniques - Radiated, radio-frequency,
electromagnetic field immunity test
IEC 61000-4-4 1995 Part 4-4: Testing and measurement EN 61000-4-4 1995
techniques - Electrical fast transient/burst
immunity test
IEC 61000-4-5 1995 Part 4-5: Testing and measurement EN 61000-4-5 1995
techniques - Surge immunity test
IEC 61000-4-8 1993 Part 4-8: Testing and measurement EN 61000-4-8 1993
techniques - Power frequency magnetic field
immunity test
IEC 61000-4-9 1993 Part 4-9: Testing and measurement EN 61000-4-9 1993
techniques - Pulse magnetic field immunity
test
IEC 61000-4-10 1993 Part 4-10: Testing and measurement EN 61000-4-10 1993
techniques - Damped oscillatory magnetic
field immunity test
Page 5
Publication Year Title EN/HD Year
IEC 61000-4-11 1994 Part 4-11: Testing and measurement EN 61000-4-11 1994
techniques - Voltage dips, short interruptions
and voltage variations immunity tests
IEC 61000-4-12 1995 Part 4-12: Testing and measurement EN 61000-4-12 1995
techniques - Oscillatory waves immunity test -
Basic EMC publication
CISPR 11 (mod) 1997 Industrial, scientific and medical (ISM) EN 55011 1998
radio-frequency equipment - Radio
disturbance characteristics - Limits and
methods of measurement
Electromagnetic compatibility - Generic EN 50081-2 1993
emission standard
Part 2: Industrial environment
INTERNATIONAL IEC
STANDARD 60044-7
First edition
1999-12
Instrument transformers –
Part 7:
Electronic voltage transformers
IEC 1999 Copyright - all rights reserved
No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical,
including photocopying and microfilm, without permission in writing from the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch
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For price, see current catalogue
60044-7 © IEC:1999 – 3 –
CONTENTS
Page
FOREWORD . 7
Clause
1 General. 9
1.1 Scope . 9
1.2 Normative references. 9
1.3 General block diagram of electronic voltage transformers . 13
2 Definitions. 15
2.1 General definitions. 15
2.2 Additional definitions for single-phase electronic protective voltage
transformers . 27
2.3 Index of symbols. 27
3 General requirements . 31
3.1 General. 29
3.2 Information to be given for enquiries, tenders and orders. 31
4 Normal and special service conditions . 31
4.1 Normal service conditions . 31
4.2 Special service conditions. 35
4.3 Earthing system . 37
5 Ratings . 37
5.1 Standard values of rated voltages. 37
5.2 Standard values of rated output . 39
5.3 Standard values of rated voltage factor. 39
5.4 Standard values of rated auxiliary power supply voltage . 41
5.5 Standard reference values of other influencing parameters. 41
6 Design requirements . 43
6.1 Insulation requirements for primary voltage sensor . 43
6.2 Insulation requirements for low-voltage components . 51
6.3 Short-circuit withstand capability. 53
6.4 Limits of temperature rise . 53
6.5 Radio interference voltage requirements. 53
6.6 Transmitted overvoltage requirements . 55
6.7 Electromagnetic compatibility requirements . 55
6.8 Reliability. 59
6.9 Abnormal conditions withstand capability . 61
6.10 Abnormal conditions signalling. 61
6.11 Mechanical requirements . 61
6.12 Earthing terminals. 63
7 Classification of tests . 63
7.1 Type tests. 63
7.2 Routine tests . 65
7.3 Special tests . 65
60044-7 © IEC:1999 – 5 –
Clause Page
8 Type tests. 65
8.1 Impulse test on primary voltage terminals . 65
8.2 Wet test for outdoor type electronic voltage transformers. 69
8.3 Tests for accuracy . 69
8.4 Test for abnormal conditions withstand capability . 71
8.5 Radio interference voltage test . 73
8.6 Transmitted overvoltage test. 73
8.7 Electromagnetic compatibility tests . 73
8.8 Impulse voltage withstand test for low-voltage components . 79
8.9 Transient performance tests . 81
9 Routine tests.81
9.1 Verification of terminal markings . 81
9.2 Power-frequency withstand tests on primary voltage terminals
and partial discharge measurement . 81
9.3 Power-frequency voltage withstand test for low-voltage components . 85
9.4 Tests for accuracy . 87
10 Special tests . 87
10.1 Chopped lightning-impulse test on primary voltage terminals . 87
10.2 Measurement of capacitance and dielectric dissipation factor . 89
10.3 Mechanical strength tests . 89
11 Markings . 91
11.1 Rating plate markings . 91
11.2 Terminal markings . 95
12 Accuracy requirements for single-phase electronic measuring voltage transformers. 95
12.1 General requirements . 95
12.2 Maintenance requirement. 97
12.3 Accuracy class designation for electronic measuring voltage transformers. 97
12.4 Standard accuracy classes for electronic measuring voltage transformers . 97
12.5 Limits of voltage error and phase displacement for electronic measuring
voltage transformers . 99
13 Additional requirements for single-phase electronic protective voltage transformers . 99
13.1 General requirements . 99
13.2 Maintenance requirements. 101
13.3 Accuracy class designation for electronic protective voltage transformers. 101
13.4 Standard accuracy classes for electronic protective voltage transformers . 101
13.5 Limits of voltage error and phase displacement for electronic protective
voltage transformers . 101
13.6 Transient performance requirements. 103
Annex A (normative) Burdens for the transient response test . 105
Annex B (informative) Technical information for electronic voltage transformers. 109
Annex C (informative) Bibliography . 137
60044-7 © IEC:1999 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
INSTRUMENT TRANSFORMERS –
Part 7: Electronic voltage transformers
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the 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, the IEC publishes International Standards. 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. The 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 the 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 National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical reports or guides and they are accepted by the National Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60044-7 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
38/242/FDIS 38/243/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 3.
The committee has decided that this publication remains valid until 2002. At this date, in
accordance with the committee's decision, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition; or
• amended.
60044-7 © IEC:1999 – 9 –
INSTRUMENT TRANSFORMERS –
Part 7: Electronic voltage transformers
1 General
1.1 Scope
This part of International Standard IEC 60044 applies to newly manufactured electronic
voltage transformers with analogue output, for use with electrical measuring instruments and
electrical protective devices at frequencies from 15 Hz to 100 Hz.
NOTE 1 Optical arrangements usually include electronic components and are therefore considered to be within
the application of this standard.
NOTE 2 Detailed information is given in annex B.
NOTE 3 Requirements specific to three-phase voltage transformers are not included in this standard but, so far as
they are relevant, the requirements in clauses 3 to 11 apply to these transformers and a few references to them are
included in those clauses (e.g. see 2.1.5, 5.1.1, 5.2, 11.2.1 and 11.2.2).
1.2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this part of IEC 60044. For dated references, subsequent amend-
ments to, or revisions of, any of these publications do not apply. However, parties to
agreements based on this part of IEC 60044 are encouraged to investigate the possibility of
applying the most recent editions of the normative documents indicated below. For undated
references, the latest edition of the normative document referred to applies. Members of IEC
and ISO maintain registers of currently valid International Standards.
IEC 60038:1983, IEC standard voltages
IEC 60044-2:1997, Instrument transformers – Part 2: Inductive voltage transformers
IEC 60050(161):1990, International Electrotechnical Vocabulary (IEV) – Chapter 161:
Electromagnetic compatibility
IEC 60050(321):1986, International Electrotechnical Vocabulary (IEV) – Chapter 321:
Instrument transformers
IEC 60050(601):1985, International Electrotechnical Vocabulary (IEV) – Chapter 601:
Generation, transmission and distribution of electricity – General
IEC 60050(604):1987, International Electrotechnical Vocabulary (IEV) – Chapter 604:
Generation, transmission and distribution of electricity – Operation
IEC 60060 (all parts), High-voltage techniques
IEC 60060-1:1989, High-voltage test techniques – Part 1: General definitions and test
requirements
IEC 60071-1:1993, Insulation co-ordination – Part 1: Definitions, principles and rules
60044-7 © IEC:1999 – 11 –
IEC 60186:1987, Voltage transformers
IEC 60255-5:1977, Electrical relays – Part 5: Insulation tests for electrical relays
IEC 60255-6:1988, Electrical relays – Part 6: Measuring relays and protection equipment
IEC 60255-11:1979, Electrical relays – Part 11: Interruptions to and alternating component
(ripple) in d.c. auxiliary energizing quantity of measuring relays
IEC 60255-22-1:1988, Electrical relays – Part 22: Electrical disturbance tests for measuring
relays and protection equipment – Section 1: 1 MHz burst disturbance tests
IEC 60270:1981, Partial discharges measurements
IEC 60617-1:1985, Graphical symbols for diagrams – Part 1: General information, general
index. Cross-reference tables
IEC 60694:1996, Common specifications for high-voltage switchgear and controlgear
standards
IEC 60721 (all parts), Classification of environmental conditions
IEC 60815:1986, Guide for the selection of insulators in respect of polluted conditions
IEC 61000 (all parts), Electromagnetic compatibility (EMC)
IEC 61000-4-1:1992, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 1: Overview of immunity test. Basic EMC publication
IEC 61000-4-2:1995, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 2: Electrostatic discharge immunity test. Basic EMC publication
IEC 61000-4-3:1995, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 3: Radiated, radio-frequency, electromagnetic immunity test
IEC 61000-4-4:1995, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 4: Electrical fast transient/burst immunity test. Basic EMC publication
IEC 61000-4-5:1995, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 5: Surge immunity test
IEC 61000-4-8:1993, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 8: Power frequency magnetic field immunity test. Basic EMC publication
IEC 61000-4-9:1993, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 9: Pulse magnetic field immunity test. Basic EMC publication
IEC 61000-4-10:1993, Electromagnetic compatibility (EMC) – Part 4: Testing and
measurement techniques – Section 10: Damped oscillatory magnetic field immunity test.
Basic EMC publication
60044-7 © IEC:1999 – 13 –
IEC 61000-4-11:1994, Electromagnetic compatibility (EMC) – Part 4: Testing and
measurement techniques – Section 11: Voltage dips, short interruption and voltage variation
immunity test
IEC 61000-4-12:1995, Electromagnetic compatibility (EMC) – Part 4: Testing and
measurement techniques – Section 12: Oscillatory waves immunity tests. Basic EMC
publication
CISPR 11 (EN 55011), Industrial, scientific and medical (ISM) radio-frequency equipment –
Electromagnetic disturbance characteristics – Limits and methods of measurement
EN 50081-2:1993, Electromagnetic compatibility – Generic immunity standard – Part 2:
Industrial environment
1.3 General block diagram of electronic voltage transformers
The applied technology decides which parts are necessary for realisation of an electronic
voltage transformer, i.e. it is not absolutely essential that all parts described be in the
transformer (see figures 1 and 2).
Primary
A a
voltage Primary Transmitting Secondary
sensor converter system converter
N n
Primary voltage Secondary voltage
terminals terminals
Primary Secondary
power power
supply supply
IEC 1192/99
Figure 1 – General block diagram of earthed single-phase electronic voltage transformers
Primary
A a
voltage
sensor
N n
Primary
B b
Primary Secondary
voltage Transmitting
converter converter
sensor system
N n
Primary
C c
voltage
sensor
N n
Primary voltage Secondary voltage
terminals terminals
Primary Secondary
power power
supply supply
IEC 1193/99
Figure 2 – General block diagram of earthed three-phase electronic voltage transformers
60044-7 © IEC:1999 – 15 –
2 Definitions
For the purpose of this part of IEC 60044, the following definitions apply.
2.1 General definitions
2.1.1
electronic instrument transformer
an arrangement consisting of one or more current or voltage sensors which may be connected
to a transmitting system and a secondary converter, all intended to transmit a measuring
quantity in a proportional quantity to supply measuring instruments, meters and protective or
control devices
2.1.2
electronic voltage transformer
an electronic instrument transformer in which the secondary voltage in normal conditions of
use is substantially proportional to the primary voltage and differs in phase from it by an angle
which is approximately zero for an appropriate direction of the connections
2.1.3
electronic measuring voltage transformer
an electronic voltage transformer intended to transmit an information signal to measuring
instruments and meters
2.1.4
unearthed electronic voltage transformer
an electronic voltage transformer in which all parts of the primary voltage sensor, including
terminals, are insulated from earth to a level corresponding to its rated insulation level
2.1.5
earthed electronic voltage transformer
a single-phase electronic voltage transformer intended to have one primary voltage terminal
directly earthed, or a three-phase electronic voltage transformer intended to have the primary
star-point directly earthed
2.1.6
secondary circuit
the external circuit receiving the information signals supplied by the secondary converter of
an electronic voltage transformer [IEV 321-01-08 modified]
2.1.7
rated primary voltage (U )
pn
the r.m.s. value of the component at frequency f of the primary voltage on which the
n
performance of an electronic voltage transformer is based [IEV 321-01-12 modified]
NOTE See clause B.2.
2.1.8
rated secondary voltage (U )
sn
the r.m.s. value of the component at frequency f of the secondary voltage on which the
n
performance of an electronic voltage transformer is based [IEV 321-01-16 modified]
NOTE See clause B.2.
60044-7 © IEC:1999 – 17 –
2.1.9
residual voltage
the vector sum of all phase-to-earth voltages in a three-phase system [IEV 321-03-09
modified]
2.1.10
rated voltage factor (k )
u
the multiplying factor to be applied to the rated primary voltage to determine the maximum
voltage at which a transformer must comply with the relevant thermal requirements for a
specified time and with the relevant accuracy requirements [IEV 321-03-12]
2.1.11
actual transformation ratio
the ratio of the actual primary voltage to the actual secondary voltage [IEV 321-01-18 modified]
2.1.12
rated transformation ratio (K )
n
the ratio of the rated primary voltage to the rated secondary voltage [IEV 321-01-20 modified]
2.1.13
burden
the admittance of the secondary circuit [IEV 321-01-25 modified]
NOTE The burden is usually expressed as the apparent power in volt-amperes, absorbed at a specified power
factor and at the rated secondary voltage.
2.1.14
rated burden
the value of the burden on which the accuracy requirements of a specification are based
[IEV 321-01-26]
2.1.15
rated output (S )
n
the value of the apparent power (in volt-amperes at a specified power factor) which the
electronic voltage transformer is intended to supply to the secondary circuit at the rated
secondary voltage and with rated burden connected to it [IEV 321-01-27 modified]
2.1.16
accuracy class
a designation assigned to an electronic voltage transformer, the voltage error and phase
displacement of which remain within specified limits under prescribed conditions of use
[IEV 321-01-24 modified]
2.1.17
rated frequency (f )
n
the value of frequency on which the requirements of this standard are based
2.1.18
rated auxiliary power supply voltage (U )
an
the auxiliary power supply voltage value on which the requirements of this standard are based
60044-7 © IEC:1999 – 19 –
2.1.19
highest voltage for equipment (U )
m
the highest r.m.s. value of phase-to-phase voltage for which the equipment is designed in
respect of its insulation as well as other characteristics relating to this voltage in the relevant
equipment standards [IEV 604-03-01]
NOTE It is the maximum value of the highest voltage of the system for which the equipment may be used.
2.1.20
rated insulation level
the combination of voltage values which characterizes the isolation of a transformer with
regard to its capability to withstand dielectric stresses
2.1.21
earth fault factor
at a given location of a three phase-system, and for a given system configuration, the ratio of
the highest r.m.s. phase-to-earth power-frequency voltage on a healthy phase during a fault to
earth affecting one or more phases at any point on the system to the r.m.s. value of phase-to-
earth power-frequency voltage which would be obtained at the given location in the absence
of any such fault [IEV 604-03-06]
2.1.22
isolated neutral system
system where the neutral point is not intentionally connected to earth, with the exception of
high impedance connections for protection or measurement purposes [IEV 601-02-24]
2.1.23
resonant earthed (neutral) system
system in which one or more neutral points are connected to earth through reactances which
approximately compensate the capacitive component of a single-phase-to-earth fault current
[IEV 601-02-27]
2.1.24
solidly earthed (neutral) system
system whose neutral point or points are directly earthed [IEV 601-02-25]
2.1.25
impedance earthed (neutral) system
system whose neutral point or points are earthed through impedances to limit earth fault
currents [IEV 601-02-26]
2.1.26
earthed neutral system
system in which the neutral is connected to earth either solidly or through a resistance or
reactance of low enough value to reduce transient oscillations and to give a current sufficient
for selective earth-fault protection
a) A three-phase system with effectively earthed neutral at a given location is a system
characterised by an earth-fault factor at this point which does not exceed 1,4.
NOTE This condition is obtained approximately when, for all system configurations, the ratio of zero-
sequence reactance to the positive-sequence reactance is less than three and the ratio of zero-sequence
resistance to positive-sequence reactance is less than one.
b) A three-phase system with non-effectively earthed neutral at a given location is a system
characterised by an earth-fault factor at this point that may exceed 1,4
60044-7 © IEC:1999 – 21 –
2.1.27
exposed installation
installation in which the apparatus is subject to overvoltages of atmospheric origin
NOTE Such installations are usually connected to overhead transmission lines, either directly, or through a short
length of cable, and not protected by surge arresters.
2.1.28
non-exposed installation
installation in which the apparatus is not subject to overvoltages of atmospheric origin
2.1.29
voltage in steady state condition
the primary voltage and the secondary voltage in an electrical steady state condition, as
defined respectively by the following equations:
u (t) = U ⋅ 2 ⋅ sin(2π ⋅ f ⋅ t + ϕ ) + U + u (t);
p p p p dc p res
u (t) = U ⋅ 2 ⋅ sin(2π ⋅ f ⋅ t + ϕ ) + U + u (t);
s s s s dc s res
where
U is the r.m.s. value of primary voltage when U = 0 and u (t) = 0;
p p dc p res
U is the r.m.s. value of secondary converter when U = 0 and u (t) = 0;
s s dc s res
f is the fundamental frequency of the network;
U is the primary direct voltage;
p dc
U is the secondary direct voltage;
s dc
ϕ is the primary phase displacement;
p
ϕ is the secondary phase displacement;
s
u (t) is the primary residual voltage including harmonic and subharmonic components;
p res
u (t) is the secondary residual voltage including harmonic and subharmonic
s res
components;
t is the instantaneous value of time.
f U U U U ϕ ϕ
, , , , , , being constant for steady-state condition.
p s p dc s dc p s
NOTE 1 Steady-state condition is a particular case of the general situation described in 2.2.4 and in annex B.
NOTE 2 Electronic voltage transformers can exhibit specific characteristics as voltage offset, delay time, etc.
Hence, while not present within IEC 60044-2, the above equations are required for an accurate presentation of the
requirements related to electronic voltage transformers. The definitions of errors, while compatible with those of
IEC 60044-2, are also improved.
2.1.30
secondary direct voltage offset (U )
s dc0
direct voltage component of the secondary voltage of an electronic voltage transformer when
U (t) = 0
p
2.1.31
voltage error for steady-state conditions(εε )
u
the error which a transformer introduces into the measurement of a voltage and which arises
when the actual transformation ratio is not equal to the rated transformation ratio
[IEV 321-01-22 modified]
The voltage error, expressed in per cent, is given by the formula:
60044-7 © IEC:1999 – 23 –
K U − U
n s p
Voltage error % = × 100
U
p
where
K is the rated transformation ratio;
n
U is the actual primary voltage;
p
U is the actual secondary voltage when U is applied under the conditions of measurement.
s p
NOTE This definition is only related to components at rated frequency of both primary and secondary voltages,
and does not take into account direct voltage components. This definition is compatible with IEC 60044-2.
2.1.32
ϕϕ )
phase displacement for steady-state conditions (
u
ϕ = ϕ – ϕ
u s p
the difference in phase between the primary voltage and the secondary voltage phasors, the
direction of the phasors being so chosen that the angle is zero for a perfect transformer. The
phase displacement is said to be positive when the secondary voltage leads the primary
voltage phasor. It is usually expressed in minutes or centiradians. ϕ can be considered to be
u
made up of two components: the rated phase offset ϕ and the rated delay time t [IEV 321-
0n dn
01-23 modified]
2.1.33
rated phase offset (ϕϕ )
0n
constant phase displacement value of the electronic voltage transformer
2.1.34
rated delay time (t )
dn
time t needed for digital data transmission and processing, included by some electronic
d
voltage transformers
2.1.35
phase error (ϕϕ )
e
the actual phase displacement without the displacement caused by the rated phase offset and
the rated delay time. The phase error is expressed in angular units relative to the rated
frequency
ϕ = ϕ – ϕ + 2 π ⋅ f ⋅ t
e 0r dr
= ϕ – ϕ – ϕ + 2 π ⋅ f ⋅ t
s p 0r dr
The phase error is usually expressed in minutes or centiradians [IEV 321-01-23 modified].
2.1.36
secondary limiting current
maximum secondary current at rated primary voltage which the transformer can supply
continuously
2.1.37
short circuit withstand capability
capability of an electronic voltage transformer to withstand a short circuit between the
secondary terminals without damage
2.1.38
connecting point
point specified by the manufacturer and provided to the user for connecting electrical cables
at site installation or for testing purposes. Where a coaxial cable is used, only the external
shield is considered to be a connecting point
60044-7 © IEC:1999 – 25 –
2.1.39
primary voltage terminals
terminals by means of which the primary voltage is supplied to the electronic voltage
transformer
2.1.40
primary voltage sensor
electric, electronic, optical or other device intended to transmit to the secondary equipment,
either directly or by means of a primary converter, a signal corresponding to the voltage
between the primary voltage terminals
2.1.41
primary converter
arrangement that converts the signal, coming from one or more primary voltage sensors into a
signal suitable for the transmitting systems
2.1.42
primary power supply
power supply to the primary converter and/or primary voltage sensor (can be combined with
the secondary power supply)
2.1.43
transmitting system
short- or long-distance coupling arrangement between primary and secondary parts intended
to transmit the signal. Depending on the technology used, the transmitting system can also be
used for power transmission
2.1.44
secondary converter
arrangement that converts the signal transmitted through the transmitting system into a
quantity proportional to the voltage between the primary terminals, in order to supply
measuring instruments, meters and protective or control devices
2.1.45
secondary power supply
power supply to the secondary converter (can be combined with the primary power supply)
2.1.46
secondary voltage terminals
terminals by means of which the voltage circuits of measuring instruments, meters and
protective or control devices are supplied
2.1.47
low-voltage components
all components other than the primary voltage sensor
2.1.48
rated supply current (I )
an
value of the current required by the auxiliary power supply in the rated conditions
2.1.49
maximum supply current (I )
a max
maximum value of the current required by the auxiliary power supply in the worst conditions
60044-7 © IEC:1999 – 27 –
2.2 Additional definitions for single-phase electronic protective voltage transformers
2.2.1
electronic protective voltage transformer
electronic voltage transformer intended to transmit an information signal to protective and
control devices
2.2.2
electronic residual voltage transformer
three-phase electronic voltage transformer or group of three single-phase electronic voltage
transformers intended to transmit an information signal representative of the residual voltage
existing in the three-phase voltages applied to the primary terminals
2.2.3
transient response
response of the secondary voltage to a transient change of the primary voltage
2.2.3.1
short circuit on the primary
decay of the secondary voltage of an electronic voltage transformer in the event of a short-
circuit between a high-voltage terminal and earth
2.2.3.2
reclosing on a line with trapped charges
transient response of an electronic voltage transformer subjected to a d.c. charge retained by
an overhead line, due to the opening and subsequent reclosing of the adjacent circuit-breaker
2.2.4
voltage in transient conditions
in the transient condition, primary and secondary voltages are defined as follows:
u (t) = U 2 ⋅ sin(2π ⋅ f ⋅ t + ϕ ) + U (t) + u (t)
p p p p dc p res
u (t) = U 2 ⋅ sin(2π ⋅ f ⋅ t + ϕ ) + U + u (t)
s s s s dc s res
NOTE Transient conditions are induced by a sudden change of one or more parameters of the primary voltage
equation given in 2.1.29 (see clause B.4).
2.2.5
instantaneous voltage error for transient conditions
K ⋅ u (t) − u (t − t )
n s p
dn
Voltage error ε (t) % = × 100
u
u 2
p
where u (t) and u (t) are described for a limited range of time by the equations given in 2.2.4.
p s
The chosen origin of the time is the instant of the sudden change of the parameters described
in 2.2.4.
NOTE See clause B.4.
2.3 Index of symbols
f frequency 2.1.29
f rated frequency 2.1.17
n
I rated supply current 2.1.48
an
60044-7 © IEC:1999 – 29 –
I maximum supply current 2.1.49
a max
k rated voltage factor 2.1.10
u
K rated transformation ratio of an electronic voltage transformer 2.1.12
n
S rated output 2.1.15
n
t instantaneous value of time 2.1.29
t rated delay time 2.1.34
dn
U rated auxiliary power supply voltage 2.1.18
an
U highest voltage for equipment 2.1.19
m
U r.m.s. value of primary voltage in steady-state condition, when
p
U = 0 and u (t) = 0 2.1.29
p dc p res
U primary direct voltage 2.1.29
p dc
U rated primary voltage 2.1.7
pn
u (t) primary voltage 2.1.29 and 2.2.4
p
u (t) primary residual voltage including harmonic and subharmonic
p res
components 2
...
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