Instrument transformers -- Part 8: Electronic current transformers

EN following parallel vote

Messwandler -- Teil 8: Elektronische Stromwandler

Transformateurs de mesure -- Partie 8: Transformateurs de courant électroniques

This part of EN 60044 applies to newly manufactured electronic current transformers having an analogue voltage output or a digital output, for use with electrical measuring instruments and electrical protective devices at nominal frequencies from 15 Hz to 100 Hz.

Instrument transformers - Part 8: Electronic current transformers

General Information

Status
Published
Publication Date
31-Aug-2003
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
01-Sep-2003
Due Date
01-Sep-2003
Completion Date
01-Sep-2003

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SLOVENSKI SIST EN 60044-8:2003
STANDARD
september 2003
Instrument transformers - Part 8: Electronic current transformers
ICS 17.220.20 Referenčna številka
SIST EN 60044-8:2003(en)

© Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

---------------------- Page: 1 ----------------------
EUROPEAN STANDARD EN 60044-8
NORME EUROPÉENNE
EUROPÄISCHE NORM September 2002
ICS 17.220.20
English version
Instrument transformers
Part 8: Electronic current transformers
(IEC 60044-8:2002)
Transformateurs de mesure Messwandler
Partie 8: Transformateurs de courant Teil 8: Elektronische Stromwandler
électroniques (IEC 60044-8:2002)
(CEI 60044-8:2002)

This European Standard was approved by CENELEC on 2002-09-01. 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,

Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta,

Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels

© 2002 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 60044-8:2002 E
---------------------- Page: 2 ----------------------
EN 60044-8:2002 - 2 -
Foreword

The text of document 38/280/FDIS, future edition 1 of IEC 60044-8, prepared by IEC TC 38,

Instrument transformers, was submitted to the IEC-CENELEC parallel vote and was approved by

CENELEC as EN 60044-8 on 2002-09-01.
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) 2003-06-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2005-09-01
Annexes designated "normative" are part of the body of the standard.
Annexes designated "informative" are given for information only.

In this standard, annexes D and ZA are normative and annexes A, B, C and E are informative.

Annex ZA has been added by CENELEC.
__________
Endorsement notice

The text of the International Standard IEC 60044-8:2002 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 60038 NOTE Harmonized as HD 472 S1:1989 (modified).
IEC 60068-2 Series NOTE Harmonized in EN 60068-2/HD 323.2 Series (not modified).
IEC 60071-2 NOTE Harmonized as EN 60071-2:1997 (not modified).
IEC 60255-24 NOTE Harmonized as EN 60255-24:2001 (not modified).
IEC 60270 NOTE Harmonized as EN 60270:2001 (not modified).
IEC 60437 NOTE Harmonized as EN 60437:1997 (not modified).
IEC 60567 NOTE Harmonized as EN 60567:1992 (not modified).
IEC 60599 NOTE EN 60599:1999 is based on IEC 60599:1999 (not modified).
IEC 60721-2-2 NOTE Harmonized as HD 478.2.2 S1:1990 (not modified).
IEC 60721-2-4 NOTE Harmonized as HD 478.2.4 S1:1989 (not modified).
IEC 61508-1 NOTE Harmonized as EN 61508-1:2001 (not modified).
IEC 61508-3 NOTE Harmonized as EN 61508-3:2001 (not modified).
IEC 61754-1 NOTE Harmonized as EN 61754-1:1997 (not modified).
IEC 61754-15 NOTE Harmonized as EN 61754-15:2001 (not modified).
__________
---------------------- Page: 3 ----------------------
- 3 - EN 60044-8:2002
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
IEC 60028 1925 International standard of resistance for--
copper
1) 2)
IEC 60044-1 - Instrument transformers EN 60044-1 1999
Part 1: Current transformers
1) 2)
IEC 60044-6 - Part 6: Requirements for protective EN 60044-6 1999
current transformers for transient
performance
1) 2)
IEC 60044-7 - Part 7: Electronic voltage transformers EN 60044-7 2000
IEC 60050-161 1990 International Electrotechnical --
Vocabulary (IEV)
Chapter 161: Electromagnetic
compatibility
IEC 60050-321 1986 International electrotechnical vocabulary--
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 60056 - High-voltage alternating-current circuit- HD 348 S7 1998
breakers
IEC 60060-1 1989 High-voltage test techniques HD 588.1 S1 1991
+ corr. March 1990 Part 1: General definitions and test
requirements
Undated reference.
Valid edition at date of issue.

HD 348 S7:1998 is superseded by EN 62271-100:2001, which is based on IEC 62271-100:2001.

---------------------- Page: 4 ----------------------
EN 60044-8:2002 - 4 -
Publication Year Title EN/HD Year
IEC 60068-2-6 1995 Environmental testing EN 60068-2-6 1995
+ corr. March 1995 Part 2: Tests - Test Fc: Vibration
(sinusoidal)
1) 2)
IEC 60068-2-17 - Part 2: Tests - Test Q: Sealing EN 60068-2-17 1994
1) 2)
IEC 60068-2-75 - Part 2-75: Tests - Test Eh: Hammer EN 60068-2-75 1997
tests
IEC 60071-1 1993 Insulation co-ordination EN 60071-1 1995
Part 1: Definitions, principles and rules
IEC 60085 1984 Thermal evaluation and classification of HD 566 S1 1990
electrical insulation
IEC 60121 - Recommendation for commercial --
annealed aluminium electrical conductor
wire
IEC 60255-5 2000 Electrical relays EN 60255-5 2001
Part 5: Insulation coordination for
measuring relays and protection
equipment - Requirements and tests
IEC 60255-22-1 1988 Part 22: Electrical disturbance tests for--
measuring relays and protection
equipment -
Section 1: 1 MHz burst disturbance
tests
IEC 60296 1982 Specification for unused mineral --
insulating oils for transformers and
switchgear
IEC 60304 1982 Standard colours for insulation for low- HD 402 S2 1984
frequency cables and wires
IEC 60376 1971 Specification and acceptance of new--
sulphur hexafluoride
IEC 60376B 1974 Second supplement: Clause 26 - -
IEC 60417 Series Graphical symbols for use on equipment EN 60417 Series
IEC 60480 1974 Guide to the checking of sulphur --
hexafluoride (SF6) taken from electrical
equipment
1) 2)
IEC 60529 - Degrees of protection provided by EN 60529 1991
enclosures (IP Code) + corr. May 1993
IEC 60664-1 1992 Insulation coordination for equipment HD 625.1 S1 1996
(mod) within low-voltage systems + corr. November 1996
Part 1: Principles, requirements and
tests
---------------------- Page: 5 ----------------------
- 5 - EN 60044-8:2002
Publication Year Title EN/HD Year
IEC 60694 1996 Common specifications for high-voltage EN 60694 1996
switchgear and controlgear standards + corr. May 1999
IEC 60707 1999 Flammability of solid non-metallic EN 60707 1999
materials when exposed to flame
sources - List of test methods
IEC 60721-3-3 1994 Classification of environmental EN 60721-3-3 1995
conditions
Part 3: Classification of groups of
environmental parameters and their
severities -
Section 3: Stationary use at
weatherprotected locations
IEC 60721-3-4 1995 Section 4: Stationary use at non- EN 60721-3-4 1995
weatherprotected locations
IEC 60794 Series Optical fibre cables EN 60794 Series
IEC 60812 1985 Analysis techniques for system HD 485 S1 1987
reliability - Procedure for failure mode
and effects analysis (FMEA)
IEC 60815 1986 Guide for the selection of insulators in--
respect of polluted conditions
IEC 60870-5-1 1990 Telecontrol equipment and systems EN 60870-5-1 1993
Part 5: Transmission protocols -
Section 1: Transmission frame formats
IEC 61000-4-1 2000 Electromagnetic compatibility (EMC) EN 61000-4-1 2000
Part 4-1: Testing and measurement
techniques - Overview of IEC 61000-4
series
1) 2)
IEC 61000-4-2 - Part 4-2: Testing and measurement EN 61000-4-2 1995
techniques - Electrostatic discharge
immunity test
1) 2)
IEC 61000-4-3 - Part 4-3: Testing and measurement EN 61000-4-3 2002
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
1) 2)
IEC 61000-4-5 - Part 4-5: Testing and measurement EN 61000-4-5 1995
techniques - Surge immunity test
IEC 61000-4-7 1991 Part 4-7: Testing and measurement EN 61000-4-7 1993
techniques - General guide on
harmonics and interharmonics
measurements and instrumentation, for
power supply systems and equipment
connected thereto
---------------------- Page: 6 ----------------------
EN 60044-8:2002 - 6 -
Publication Year Title EN/HD Year
1) 2)
IEC 61000-4-8 - Part 4-8: Testing and measurement EN 61000-4-8 1993
techniques - Power frequency magnetic
field immunity test
1) 2)
IEC 61000-4-9 - Part 4-9: Testing and measurement EN 61000-4-9 1993
techniques - Pulse magnetic field
immunity test
1) 2)
IEC 61000-4-10 - Part 4-10: Testing and measurement EN 61000-4-10 1993
techniques - Damped oscillatory
magnetic field immunity test
1) 2)
IEC 61000-4-11 - Part 4-11: Testing and measurement EN 61000-4-11 1994
techniques - Voltage dips, short
interruptions and voltage variations
immunity tests
1) 2)
IEC 61000-4-12 - Part 4-12: Testing and measurement EN 61000-4-12 1995
techniques - Oscillatory waves immunity
test
1) 2)
IEC 61000-4-13 - Part 4-13: Testing and measurement EN 61000-4-13 2002
techniques - Harmonics and
interharmonics including mains
signalling at a.c. power port, low
frequency immunity tests
IEC 61000-4-29 2000 Part 4-29: Testing and measurement EN 61000-4-29 2000
techniques - Voltage dips, short
interruptions and voltage variations on
d.c. input power port immunity tests
IEC 61025 1990 Fault tree analysis (FTA) HD 617 S1 1992
IEC 61166 1993 High-voltage alternating current circuit- EN 61166 1993
breakers - Guide for seismic
qualification of high-voltage alternating
current circuit-breakers
IEC/TS 61462 1998 Composite insulators - Hollow insulators--
for use in outdoor and indoor electrical
equipment - Definitions, test methods,
acceptance criteria and design
recommendations
1) 2)
IEC 61850-3 - Communication networks and systems EN 61850-3 2002
in substations
Part 3: General requirements
IEC 61850-9-1 - Part 9-1: Specific communication --
system mappings (SCSM) - Serial
unidirectional multidrop point to point
link
To be published.
---------------------- Page: 7 ----------------------
- 7 - EN 60044-8:2002
Publication Year Title EN/HD Year
CISPR 11 1997 Industrial, scientific and medical (ISM) EN 55011 1998
(mod) radio-frequency equipment - Radio
disturbance characteristics - Limits and
methods of measurement
A1 1999 A1 1999
EIA RS-485 - Standard for electrical characteristics of--
generators and receivers for use in
balanced digital multipoint systems
- - Voltage characteristics of electricity EN 50160 1999
supplied by public distribution systems
---------------------- Page: 8 ----------------------
INTERNATIONAL IEC
STANDARD
60044-8
First edition
2002-07
Instrument transformers –
Part 8:
Electronic current transformers
Transformateurs de mesure –
Partie 8:
Transformateurs de courant électroniques
 IEC 2002  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

PRICE CODE
Commission Electrotechnique Internationale
International Electrotechnical Commission
Международная Электротехническая Комиссия
For price, see current catalogue
---------------------- Page: 9 ----------------------
– 2 – 60044-8  IEC:2002(E)
CONTENTS

FOREWORD .......................................................................................................................... 6

1 Scope .............................................................................................................................. 7

1.1 General .................................................................................................................. 7

1.2 General block diagram of electronic current transformers ........................................ 8

1.3 General block diagram of electronic transformers with a digital output ..................... 9

2 Normative references....................................................................................................... 9

3 Definitions.......................................................................................................................12

3.1 General definitions.................................................................................................12

3.2 Additional definitions for measuring electronic current transformers........................19

3.3 Additional definitions for protective electronic current transformers.........................19

3.4 Additional definitions for digital output ....................................................................22

3.5 Additional definitions for analogue voltage output ...................................................23

3.6 Index of main definitions and abbreviations ............................................................23

4 Normal and special service conditions .............................................................................24

4.1 General .................................................................................................................24

4.2 Normal service conditions ......................................................................................25

4.3 Special service conditions ......................................................................................26

4.4 System earthing.....................................................................................................28

5 Ratings ...........................................................................................................................28

5.1 General ratings ......................................................................................................28

5.2 Standard values for rated phase offset ...................................................................32

5.3 Rating for digital output ..........................................................................................32

5.4 Rating for analogue voltage output .........................................................................33

6 Design requirements .......................................................................................................34

6.1 General design requirements .................................................................................34

6.2 Design requirements for digital output ....................................................................43

6.3 Design requirements for analogue voltage output ...................................................60

7 Classification of tests ......................................................................................................60

7.1 General .................................................................................................................60

7.2 Type tests..............................................................................................................60

7.3 Routine tests..........................................................................................................61

7.4 Special tests ..........................................................................................................62

8 Type test.........................................................................................................................62

8.1 Short-time current tests..........................................................................................62

8.2 Temperature-rise test.............................................................................................63

8.3 Impulse tests on primary terminals .........................................................................63

8.4 Wet test for outdoor type electronic current transformers........................................65

8.5 RIV tests................................................................................................................65

8.6 Transmitted overvoltage test ..................................................................................65

8.7 Low-voltage components voltage withstand test......................................................66

8.8 EMC tests..............................................................................................................67

8.9 Accuracy test .........................................................................................................70

8.10 Additional accuracy tests for protective electronic current transformers ..................72

8.11 Verification of the protection...................................................................................72

8.12 Tightness tests ......................................................................................................73

8.13 Vibration tests........................................................................................................73

8.14 Additional type test for digital output.......................................................................74

---------------------- Page: 10 ----------------------
60044-8  IEC:2002(E) – 3 –

9 Routine tests...................................................................................................................75

9.1 Verification of terminal markings ............................................................................75

9.2 Power-frequency withstand tests on primary terminals

and partial discharge measurement........................................................................75

9.3 Power-frequency voltage withstand test for low-voltage components.......................75

9.4 Accuracy tests .......................................................................................................75

9.5 Tightness tests ......................................................................................................75

9.6 Additional routine tests for digital output .................................................................76

9.7 Additional routine tests for analogue output ............................................................76

10 Special tests ...................................................................................................................76

10.1 Chopped lightning-impulse test on primary terminals ..............................................76

10.2 Measurement of capacitance and dielectric dissipation factor .................................76

10.3 Mechanical tests ....................................................................................................76

10.4 Tests for accuracy versus harmonics .....................................................................77

10.5 Tests in accordance with the technology applied ....................................................78

11 Marking...........................................................................................................................78

11.1 Terminal marking – General rules ..........................................................................78

11.2 Rating plate markings ............................................................................................79

12 Additional requirements for measuring electronic current transformers ............................82

12.1 Accuracy class designation ....................................................................................82

12.2 Limits of current error and phase error at rated frequency.......................................82

12.3 Accuracy requirements on harmonics .....................................................................83

13 Additional requirements for protective electronic current transformers .............................83

13.1 Accuracy classes ...................................................................................................83

13.2 Accuracy requirements on harmonics .....................................................................84

14 Information to be given with enquiries, tenders and orders...............................................84

14.1 Designation............................................................................................................84

14.2 Dependability.........................................................................................................85

15 Rules for transport, storage and installation.....................................................................85

15.1 Conditions during transport, storage and installation...............................................86

15.2 Installation .............................................................................................................86

15.3 Unpacking and lifting..............................................................................................86

15.4 Assembly...............................................................................................................86

15.5 Operation...............................................................................................................87

15.6 Maintenance ..........................................................................................................87

16 Safety .............................................................................................................................90

16.1 Electrical aspects...................................................................................................90

16.2 Mechanical aspects................................................................................................90

16.3 Thermal aspects ....................................................................................................90

Annex A (informative) Transient performances of ECTs ........................................................91

Annex B (informative) Technical information for electronic current transformers

with digital output ..................................................................................................................98

Annex C (informative) Technical information for electronic current transformers

with analogue output ...........................................................................................................108

Annex D (normative) Frequency response and accuracy requirements on harmonics for

electronic current and voltage transformer ...........................................................................116

Annex E (informative) Graph explaining the accuracy requirements.....................................123

---------------------- Page: 11 ----------------------
– 4 – 60044-8  IEC:2002(E)

Bibliography ........................................................................................................................124

Figure 1 – General block diagram of a single-phase electronic current transformer ................. 8

Figure 2 – Example of digital interface block diagram.............................................................. 9

Figure 3 – Altitude correction factor .......................................................................................27

Figure 4 – Manchester coding................................................................................................43

Figure 5 – Characteristics of the optical pulse........................................................................45

Figure 6 – Test circuit for the optical pulse.............................................................................45

Figure 7 – Copper wire interface............................................................................................47

Figure 8 – Eye diagram .........................................................................................................48

Figure 9 – Daisy-chain architecture........................................................................................49

Figure 10 – Frame format according to FT3 ...........................................................................51

Figure 11 – Status word #1....................................................................................................56

Figure 12 – Status word #2....................................................................................................57

Figure 13 – Universal frame...................................................................................................58

Figure 14 – Pulse shape for clock input .................................................................................59

Figure 15 – Example of subassembly subjected to EMC tests ................................................68

Figure 16 – Temperature cycle accuracy test .........................................................................71

Figure A.1 – Equivalent electrical circuit of the network..........................................................91

Figure A.2 – More complex equivalent electrical circuit during short circuit .............................92

Figure A.3 – Equivalent electrical circuit of magnetic current transformer during short circuit..93

Figure A.4 – Magnetic reactance of the a CT without remanence ...........................................93

Figure A.5 – Magnetic reactance of the CT with remanence ...................................................94

Figure A.6 – Example of magnetic reactance of the a CT for a TPZ class...............................95

Figure A.7 – Example of the magnetic reactance of a CT for a TPY class...............................96

Figure B.1 – Combination of ECTs and EVTs to form the digital output...................................98

Figure B.2 – Synchronized samples of current from bay 1 and bay 2

calculated from non-synchronized samples from bay 1 and bay 2 respectively......................101

Figure B.3 – Samples from current in bay 1 and 2 sampled synchronized

by a common clock..............................................................................................................101

Figure B.4 – Phase error definition for the digital interface ...................................................102

Figure B.5 – Test set-up ......................................................................................................103

Figure B.6 – Comparison of errors in conventional metering systems and systems based

on ECTs and EVTs with digital output ..................................................................................107

Figure C.1 – Test circuit for accuracy measurements in steady state....................................109

Figure C.2 – Iron-core-coil transformer ................................................................................110

Figure C.3 – Equivalent circuit of the iron-core current transformer with voltage output.........111

Figure C.4 – Stand-alone air-core coil..................................................................................112

Figure C.5 – Equivalent circuit of stand-alone air-core current transformer

with voltage output ..............................................................................................................113

Figure C.6 – Phasor diagram – Stand-alone air-core coil......................................................114

Figure D.1 – Digital data acquisition system.........................................................................118

Figure E.1 – Accuracy limits of a multi-purpose ECT ............................................................123

---------------------- Page: 12 ----------------------
60044-8  IEC:2002(E) – 5 –

Table 1 – Temperature categories .........................................................................................25

Table 2 – Limits of temperature rise of the transformer ..........................................................30

Table 3 – DC voltage.............................................................................................................31

Table 4 – AC voltage ...................................................................................

...

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