IEC 61557-9:2023

Electrical safety in low voltage distribution systems up to 1 000 V AC and 1 500 V DC - Equipment for testing, measuring or monitoring of protective measures - Part 9: Equipment for insulation fault location in IT systems

IEC 61557-9:2023 specifies the requirements for the insulation fault location system (IFLS) that localizes insulation faults in any part of the system in unearthed IT AC systems and unearthed IT AC systems with galvanically connected DC circuits having nominal voltages up to 1 000 V AC, as well as in unearthed IT DC systems with voltages up to 1 500 V DC, independent of the measuring principle. IEC 61557-9:2023 cancels and replaces the third edition published in 2014. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
a) new terms and definitions on maximum admissible locating AC and DC currents and voltages;
b) the requirements on locating current and locating voltage have been revised;
c) performance requirements have been added;
d) the test requirements for locating current and locating voltage have been revised;
e) the structure of this document has been adapted to that of IEC 61557-1:2019;
f) the limit values under Clause A.2 were adapted to fit the changed test methods in 6.2.3.

Sécurité électrique dans les réseaux de distribution basse tension au plus égale à 1 000 V en C.A et 1 500 V en C.C - Dispositifs de contrôle, de mesure ou de surveillance de mesures de protection - Partie 9: Dispositifs de localisation de défauts d'isolement pour réseaux IT

L'IEC 61557-9:2023 spécifie les exigences applicables aux dispositifs de localisation de défauts d’isolement (DLD) qui, indépendamment du principe de mesure, peuvent localiser les défauts d’isolement des parties de réseaux IT à courant alternatif non mis à la terre et des réseaux IT à courant alternatif non mis à la terre comprenant des circuits à courant continu reliés galvaniquement dont les tensions nominales sont au plus égales à 1 000 V en courant alternatif, et de réseaux IT à courant continu non mis à la terre dont les tensions sont au plus égales à 1 500 V en courant continu. L'IEC 61557-9:2023 annule et remplace la troisième édition parue en 2014. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l’édition précédente:
a) ajout de nouveaux termes et de nouvelles définitions sur les courants et tensions, alternatifs et continus, de localisation maximaux admissibles;
b) révision des exigences relatives au courant de localisation et à la tension de localisation;
c) ajout d’exigences de performance;
d) révision des exigences d’essai pour le courant de localisation et la tension de localisation;
e) modification de la structure du présent document pour s’adapter à l’IEC 61557-1:2019;
f) modification des valeurs limites de l’Article A.2 pour s’adapter aux méthodes d’essai modifiées en 6.2.3.

General Information

• Status: Published
• Publication Date: 13-Dec-2023
• ICS: 25.040.40 - Industrial process measurement and control
• Technical Committee: TC 85 - Measuring equipment for electrical and electromagnetic quantities
• Drafting Committee: WG 8 - TC 85/WG 8
• Current Stage: PPUB - Publication issued
• Start Date: 15-Dec-2023
• Completion Date: 14-Dec-2023

Relations

• Revises: IEC 61557-9:2014 - Electrical safety in low voltage distribution systems up to 1 000 V a.c. and 1 500 V d.c. - Equipment for testing, measuring or monitoring of protective measures - Part 9: Equipment for insulation fault location in IT systems
• Effective Date: 05-Sep-2023
• Revises: IEC 61557-9:2014/COR1:2016 - Corrigendum 1 - Electrical safety in low voltage distribution systems up to 1 000 V a.c. and 1 500 V d.c. - Equipment for testing, measuring or monitoring of protective measures - Part 9: Equipment for insulation fault location in IT systems
• Effective Date: 05-Sep-2023
• Revises: IEC 61557-9:2014/COR2:2017 - Corrigendum 2 - Electrical safety in low voltage distribution systems up to 1 000 V a.c. and 1 500 V d.c. - Equipment for testing, measuring or monitoring of protective measures - Part 9: Equipment for insulation fault location in IT systems
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 61557-9 ®
Edition 4.0 2023-12
COMMENTED VERSION
INTERNATIONAL
STANDARD
colour
inside
Electrical safety in low voltage distribution systems up to 1 000 V AC and 1 500 V
DC – Equipment for testing, measuring or monitoring of protective measures –
Part 9: Equipment for insulation fault location in IT systems
All rights reserved. Unless otherwise specified, 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
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.
IEC Secretariat Tel.: [phone]
3, rue de Varembé [e-mail]
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.
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IEC 61557-9 ®
Edition 4.0 2023-12
COMMENTED VERSION
INTERNATIONAL
STANDARD
colour
inside
Electrical safety in low voltage distribution systems up to 1 000 V AC and 1 500 V
DC – Equipment for testing, measuring or monitoring of protective measures –
Part 9: Equipment for insulation fault location in IT systems
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 25.040.40 ISBN 978-2-8322-8055-3
– 2 – IEC 61557-9:2023 CMV © IEC 2023
CONTENTS
FOREWORD .5
1 Scope .7
2 Normative references .7
3 Terms, definitions and abbreviated terms .9
3.1 Terms, definitions, symbols and units .9
3.2 Abbreviated terms and symbols. 12
4 Requirements . 13
4.1 General requirements . 13
4.2 Mandatory Functions provided by an IFLS . 14
4.2.1 Location warning . 14
4.2.2 Local location warning (LLW) . 14
4.2.3 Remote location warning (RLW) . 14
4.3 Optional functions provided by IFLS . 15
4.3.1 Indication of the insulation value . 15
Performance of the IFLS Alarm in case of the interruption of the loss of
the connection to the locating current sensor (LCS) . 15
4.3.3 Self-test . 15
4.4 Performance requirements . 15
4.4.1 Response sensitivity . 15
Locating current I
L .
Locating voltage U
L .
4.4.2 Locating current I and locating voltage U . 16
L L
4.4.3 Permanently admissible nominal voltage U . 16
pa
4.4.4 Supply voltage U . 16
s
4.5 Safety requirements . 17
General .
4.5.1 Clearance and creepage distances . 17
4.5.2 Protection class and earth connection of the IFLS . 17
4.6 Electromagnetic compatibility . 17
4.7 Mechanical requirements . 18
General .
4.7.1 Product mechanical robustness. 18
IP protection class requirements . 19
4.8 Climatic environmental conditions . 19
5 Marking and operating instructions . 19
5.1 Marking . 19
5.2 Operating instructions . 19
6 Tests . 20
6.1 General . 20
6.2 Type tests . 21
General .
6.2.1 Climatic tests . 21
Test of response sensitivity of the IFLS . 21
Test of the locating current I and locating voltage U . 22
L L
Test of the locating voltage U
L .

Test of the location warning . 28
Test of the indication of the insulation value . 28
6.2.6 Verification of insulation coordination . 28
Test of the performance of the LCI .
Voltage test .
Test of the electromagnetic compatibility (EMC) . 28
Test of the loss of LCS connection . 28
Test of the protection class and of the earth connection of the IFLS . 28
Inspection of the marking and operating instructions . 28
Mechanical test . 29
6.2.12 Record of the type test . 29
6.3 Routine tests . 29
General . 29
Test of the response sensitivity .
Test of the location warning .
Test of the self-test function .
Voltage test . 30
Compliance with the tests of Clause 6 .
6.3.3 Recording of routine tests . 30
7 Overview of requirements and tests for IFLS . 30
Annex A (normative) Equipment for Insulation fault location system in medical
locations (MED-IFLS) . 32
A.1 Scope General . 32
A.2 Requirements . 32
A.2.1 General . 32
A.2.2 Performance requirements . 32
A.2.3 Electromagnetic compatibility . 33
A.3 Marking and operating instructions .
A.4 Tests .
A.3 Additional tests . 34
A.3.1 General . 34
A.3.2 Test of the performance requirements . 34
A.3.3 Test of the response time . 34
A.3.4 Test of the electromagnetic compatibility (EMC) . 34
Annex B (normative) Portable equipment for insulation fault location . 36
B.1 Scope General . 36
B.2 Additional requirements . 36
B.2.1 General . 36
B.2.2 Performance requirements . 36
B.3 Marking and operating instructions . 36
B.4 Additional tests . 36
Annex C (informative) Example of an IFLS and explanation of upstream and
downstream system leakage capacitances . 38
C.1 Examples for the functions of an IFLS . 38
C.2 Upstream and downstream system leakage capacitance . 40
Bibliography . 41
List of comments . 42

– 4 – IEC 61557-9:2023 CMV © IEC 2023
Figure 1 – Test configuration: I driven directly from the system to be monitored . 25
L
Figure 2 – Test configuration: Independent locating voltage source with a locating
voltage equal or below 50 V a.c. or 120 V d.c. .
Figure 2 – Test configuration: Active locating source . 26
Figure 3 – Test configuration: Independent voltage source is used with a locating
voltage above 50 V a.c. or 120 V d.c.
Figure 3 – Test configuration for current testing: Active locating source is used with a
locating voltage above 50 V AC RMS and 70 V peak or 120 V DC .
...

IEC 61557-9 ®
Edition 4.0 2023-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electrical safety in low voltage distribution systems up to 1 000 V AC and
1 500 V DC – Equipment for testing, measuring or monitoring of protective
measures –
Part 9: Equipment for insulation fault location in IT systems

Sécurité électrique dans les réseaux de distribution basse tension au plus égale
à 1 000 V C.A et 1 500 V C.C – Dispositifs de contrôle, de mesure ou de
surveillance de mesures de protection –
Partie 9: Dispositifs de localisation de défauts d'isolement pour réseaux IT
All rights reserved. Unless otherwise specified, 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
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

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About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.

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IEC 61557-9 ®
Edition 4.0 2023-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electrical safety in low voltage distribution systems up to 1 000 V AC and

1 500 V DC – Equipment for testing, measuring or monitoring of protective

measures –
Part 9: Equipment for insulation fault location in IT systems

Sécurité électrique dans les réseaux de distribution basse tension au plus égale

à 1 000 V C.A et 1 500 V C.C – Dispositifs de contrôle, de mesure ou de

surveillance de mesures de protection –

Partie 9: Dispositifs de localisation de défauts d'isolement pour réseaux IT

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 25.040.40  ISBN 978-2-8322-7836-9

– 2 – IEC 61557-9:2023 © IEC 2023
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms, definitions and abbreviated terms . 9
3.1 Terms, definitions, symbols and units . 9
3.2 Abbreviated terms and symbols . 12
4 Requirements . 13
4.1 General requirements . 13
4.2 Functions provided by an IFLS . 14
4.2.1 Location warning . 14
4.2.2 Local location warning (LLW) . 14
4.2.3 Remote location warning (RLW). 14
4.3 Optional functions provided by IFLS . 14
4.3.1 Indication of the insulation value . 14
4.3.2 Alarm in case of the interruption of the loss of the connection to the
locating current sensor (LCS) . 14
4.3.3 Self-test . 14
4.4 Performance requirements . 15
4.4.1 Response sensitivity . 15
4.4.2 Locating current I and locating voltage U . 15
L L
4.4.3 Permanently admissible nominal voltage U . 15
pa
4.4.4 Supply voltage U . 16
s
4.5 Safety requirements . 16
4.5.1 Clearance and creepage distances . 16
4.5.2 Protection class and earth connection of the IFLS . 16
4.6 Electromagnetic compatibility . 16
4.7 Mechanical requirements . 16
4.7.1 Product mechanical robustness . 16
4.7.2 IP protection class requirements . 16
4.8 Climatic environmental conditions . 17
5 Marking and operating instructions . 17
5.1 Marking . 17
5.2 Operating instructions . 17
6 Tests . 18
6.1 General . 18
6.2 Type tests . 18
6.2.1 Climatic tests . 18
6.2.2 Test of response sensitivity of the IFLS . 19
6.2.3 Test of the locating current I and locating voltage U . 20
L L
6.2.4 Test of the location warning . 23
6.2.5 Test of the indication of the insulation value . 23
6.2.6 Verification of insulation coordination . 23
6.2.7 Test of the electromagnetic compatibility (EMC) . 23
6.2.8 Test of the loss of LCS connection . 23
6.2.9 Test of the protection class and of the earth connection of the IFLS . 23
6.2.10 Inspection of the marking and operating instructions . 23

6.2.11 Mechanical test . 23
6.2.12 Record of the type test . 24
6.3 Routine tests. 24
6.3.1 General . 24
6.3.2 Voltage test . 24
6.3.3 Recording of routine tests . 24
7 Overview of requirements and tests for IFLS . 25
Annex A (normative) Insulation fault location system in medical locations (MED-IFLS) . 26
A.1 General . 26
A.2 Requirements . 26
A.2.1 General . 26
A.2.2 Performance requirements . 26
A.2.3 Electromagnetic compatibility . 26
A.3 Additional tests . 27
A.3.1 General . 27
A.3.2 Test of the performance requirements . 27
A.3.3 Test of the response time . 27
A.3.4 Test of the electromagnetic compatibility (EMC) . 27
Annex B (normative) Portable equipment for insulation fault location . 29
B.1 General . 29
B.2 Additional requirements . 29
B.2.1 General . 29
B.2.2 Performance requirements . 29
B.3 Marking and operating instructions . 29
B.4 Additional tests .
...