CSA C61869-2:14

(IEC 61869-2:2012, MOD)

National Standard of Canada Norme nationale du Canada (reaffirmed/confirmée en 2019)

CSA C61869-2:14

Instrument transformers — Part 2: Additional requirements for current transformers

(IEC 61869-2:2012, MOD)

CSA C61869-2:14

Transformateurs de mesure — Partie 2 : Exigences supplémentaires concernant les transformateurs de courant

(IEC 61869-2:2012, MOD)

© IEC 2012. © Canadian Standards Association 2014. All rights reserved. Unauthorized reproduction is strictly prohibited. REVISED DECEMBER 2020

© IEC 2012. © Association canadienne de normalisation 2014. Tous droits réservés. Toute reproduction sans autorisation est strictement interdite. RÉVISÉE EN DÉCEMBRE 2020

Revision History

CSA C61869-2:14, Instrument transformers — Part 2: Additional requirements for current transformers

National Standard of Canada

CSA C61869-2:14

Instrument transformers — Part 2: Additional requirements for current transformers

(IEC 61869-2:2012, MOD)

Prepared by

International Electrotechnical Commission

Reviewed by

®A trademark of the Canadian Standards Association, operating as “CSA Group”

Published in December 2014 by CSA Group A not-for-profit private sector organization

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ICS 17.220.20

ISBN 978-1-77139-571-7

© 2014 Canadian Standards Association

All rights reserved. No part of this publication may be reproduced in any form whatsoever without the prior permission of the publisher.

CSA C61869-2:14

Instrument transformers — Part 2: Additional requirements for

current transformers

CSA C61869-2:14

Instrument transformers — Part 2: Additional requirements for current transformers

(IEC 61869-2:2012, MOD)

CSA Preface

This is the first edition of CAN/CSA-C61869-2, Instrument transformers — Part 2: Additional requirements for current transformers, which is an adoption, with Canadian deviations, of the identically titled IEC (International Electrotechnical Commission) Standard 61869-2:2012 (edition 1.0:2012).

Together with CAN/CSA-C61869-1, it supersedes CAN/CSA-C60044-1, Instrument transformers — Part 1: Current transformers, which was published in 2007.

For brevity, this Standard will be referred to as “CAN/CSA-C61869-2” throughout.

This Standard is part of the C61869 series of standards on instrument transformers, which consists of adoptions with Canadian deviations of the IEC 61869 series of standards. The IEC 61869 series restructures and updates the previous IEC 60044 series of standards. Requirements common to a variety of instrument transformer types are grouped in CAN/CSA-C61869-1; the remaining standards in the series state requirements for specific types of instrument transformers.

This Standard was reviewed for Canadian adoption by the CSA Technical Committee on Instrument Transformers, under the jurisdiction of the CSA Strategic Steering Committee on Power Engineering and Electromagnetic Compatibility, and has been formally approved by the Technical Committee.

This Standard has been developed in compliance with Standards Council of Canada requirements for National Standards of Canada. It has been published as a National Standard of Canada by CSA Group.

© 2014 Canadian Standards Association

All rights reserved. No part of this publication may be reproduced in any form whatsoever without the prior permission of the publisher. IEC material is reprinted with permission. Where the words “this International Standard” appear in the text, they should be interpreted as “this National Standard of Canada”.

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CSA C61869-2:14

Instrument transformers — Part 2: Additional requirements for

current transformers

This Standard is subject to review within five years from the date of publication, and suggestions for its improvement will be referred to the appropriate committee. To submit a proposal for change, please send the following information to inquiries@csagroup.org and include “Proposal for change” in the subject line:

1. Standard designation (number);

2. relevant clause, table, and/or figure number;

3. wording of the proposed change; and

4. rationale for the change.

– 2 – 61869-2 © IEC:2012

CONTENTS

FOREWORD 5

1. Scope 8

2. Normative references 8

3. Terms and definitions 8

3.1 General definitions 8

1. Definitions related to current ratings 9

2. Definitions related to accuracy 10

3.7 Index of abbreviations 18

5 Ratings 20

5.3 Rated insulation levels 20

5.3.2 Rated primary terminal insulation level 20

5.3.5 Insulation requirements for secondary terminals 20

5.3.201 Inter-turn insulation requirements 20

1. Rated output 20

   1. Rated output values 20

   2. Rated resistive burden values 20

2. Rated accuracy class 21

   1. Measuring current transformers 21

   2. Protective current transformers 22

   3. Class assignments for selectable-ratio current transformers 26

1. Standard values for rated primary current 26

2. Standard values for rated secondary current 27

3. Standard values for rated continuous thermal current 27

4. Short-time current ratings 27

   1. Rated short-time thermal current (Ith) 27

   2. Rated dynamic current (Idyn) 27

6 Design and construction 27

6.4 Requirements for temperature rise of parts and components 27

6.4.1 General 27

1. Markings 27

   1. Terminal markings 27

   2. Rating plate markings 28

1. Tests 30

   1. General 30

      1. Lists of tests 30

   2. Type tests 31

      1. Temperature-rise test 31

      2. Impulse voltage withstand test on primary terminals 33

         7.2.6 Tests for accuracy 33

         7.2.201 Short-time current tests 35

   3. Routine tests 36

7.3.1 Power-frequency voltage withstand tests on primary terminals 36

7.3.5 Tests for accuracy 36

1. Determination of the secondary winding resistance (Rct) 38

2. Determination of the secondary loop time constant (Ts) 38

   61869-2 © IEC:2012 – 3 –

3. Test for rated knee point e.m.f. (Ek) and exciting current at Ek 39

4. Inter-turn overvoltage test 39

1. Special tests 40

   7.4.3 Measurement of capacitance and dielectric dissipation factor 40

   7.4.6 Internal arc fault test 40

2. Sample tests 41

   1. Determination of the remanence factor 41

   2. Determination of the instrument security factor (FS) of

measuring current transformers 41

Annex 2A (normative) Protective current transformers classes P, PR 42

Annex 2B (normative) Protective current transformer classes for transient

performance 47

Annex 2C (normative) Proof of low-leakage reactance type 63

Annex 2D (informative) Technique used in temperature rise test of oil-immersed

transformers to determine the thermal constant by an experimental estimation 64

Annex 2E (informative) Alternative measurement of the ratio error (ε) 66

Annex 2F (normative) Determination of the turns ratio error 68

Figure 201 – Duty cycles 15

Figure 202 – Primary time constant TP 16

Figure 203 – Secondary linked flux for different fault inception angles  17

Figure 2A.1 – Vector Diagram 42

Figure 2A.2 – Error triangle 43

Figure 2A.3 – Typical current waveforms 44

Figure 2A.4 – Basic circuit for 1:1 current transformer 44

Figure 2A.5 – Basic circuit for current transformer with any ratio 45

Figure 2A.6 – Alternative test circuit 45

Figure 2B.1 – Short-circuit current for two different fault inception angles 48

Figure 2B.2 – max(t) as the curve of the highest flux values, considering all relevant

fault inception angles  48

Figure 2B.3 – Relevant time ranges for calculation of transient factor 49

Figure 2B.4 – Determination of Ktf in time range 1 at 50 Hz for Ts = 1,8 s 50

Figure 2B.5 – Determination of Ktf in time range 1 at 60 Hz for Ts = 1,5 s 50

Figure 2B.6 – Determination of Ktf in time range 1 at 16,7 Hz for Ts = 5.5 s 50

Figure 2B.7 – Limiting the magnetic flux by considering core saturation 52

Figure 2B.8 – Basic circuit 53

Figure 2B.9 – Determination of remanence factor by hysteresis loop 55

Figure 2B.10 – Circuit for d.c. method 56

Figure 2B.11 – Time-amplitude and flux-current diagrams 56

Figure 2B.12 – Recordings with shifted flux base line 57

Figure 2B.13 – Circuit for capacitor discharge method 58

Figure 2B.14 – Typical records for capacitor discharge method 59

Figure 2B.15 – Measurement of error currents 60

Figure 2D.1 – Graphical extrapolation to ultimate temperature rise 65

Figure 2E.1 – Simplified equivalent circuit of the current transformer 66

– 4 – 61869-2 © IEC:2012

Table 201 – Limits of ratio error and phase displacement for measuring current

transformers (classes 0,1 to 1) 21

Table 202 – Limits of ratio error and phase displacement for measuring current

transformers (classes 0,2S and 0,5S) 22

Table 203 – Limits of ratio error for measuring current transformers (classes 3 and 5) 22

Table 204 – Characterisation of protective classes 23

Table 205 – Error limits for protective current transformers class P and PR 23

Table 206 – Error limits for TPX, TPY and TPZ current transformers 25

Table 207 – Specification Methods for TPX, TPY and TPZ current transformers 26

Table 208 – Marking of terminals 28

Table 10 – List of tests 31

– 8 – 61869-2 © IEC:2012

INSTRUMENT TRANSFORMERS –

Part 2: Additional requirements for Current Transformers

1. Scope

   
   

   This part of IEC 61869 is applicable to newly manufactured inductive current transformers for use with electrical measuring instruments and/or electrical protective devices having rated frequencies from 15 Hz to 100 Hz.

   
   

2. Normative references

   
   

   Clause 2 of IEC 61869-1:2007 is applicable with the following additions:

   
   

   IEC 61869-1:2007, Instrument Transformers – Part 1: General requirements

   
   

3. Terms and definitions

For the purposes of this document, the terms and definitions in IEC 61869-1:2007 apply with the following additions:

3.1 General definitions 3.1.201

current transformer

instrument transformer in which the secondary current, under 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

[SOURCE: IEC 60050-321:1986, 321-02-01]

3.1.202

measuring current transformer

current transformer intended to transmit an information signal to measuring instruments and meters

[SOURCE: IEC 60050-321:1986, 321-02-18]

3.1.203

protective current transformer

a current transformer intended to transmit an information signal to protective and control devices

[SOURCE: IEC 60050-321: 1986, 321-02-19)

3.1.204

class P protective current transformer

protective current transformer without remanent flux limit, for which the saturation behaviour in the case of a symmetrical short-circuit is specified

3.1.205

class PR protective current transformer

protective current transformer with remanent flux limit, for which the saturation behaviour in the case of a symmetrical short-circuit is specified