SIST EN 61557-15:2014
(Main)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 15: Functional safety requirements for insulation monitoring devices and for equipment for insulation fault location in IT systems (IEC 61557-15:2014)
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 15: Functional safety requirements for insulation monitoring devices and for equipment for insulation fault location in IT systems (IEC 61557-15:2014)
IEC 61557-15:2014 specifies requirements related to functional safety and is based on the IEC 61508 standard series for the realization of Insulation Monitoring Devices (IMD) as specified in IEC 61557-8 and for Insulation Fault Location Systems (IFLS) according to IEC 61557-9, according to phase 10 of the IEC 61508-1 lifecycle. These devices provide safety related functions for IT systems. This part of IEC 61557 is - concerned only with functional safety requirements intended to reduce the functional risk during the use of IMDs and IFLSs; - restricted to risks arising directly from the device itself or from several IMDs or IFLSs working together in a system; and - intended to define the basic safety functions provided by the devices. This part of IEC 61557 does not - deal with electrical safety according to IEC 61010-1 and the requirements of IEC 61557-8 and IEC 61557-9; - cover the hazard and risk analysis of a particular use of the IMD or IFLS; - identify all the safety functions for the application in which the IMD or IFLS is used; and - cover the IMD or IFLS manufacturing process. This part of IEC 61557 is to be used in conjunction with Part 8 and Part 9. Functional safety requirements depend on the application and should be considered as part of the overall risk assessment of the specific application. The supplier of IMDs and IFLSs is not responsible for the application. The application designer is responsible for the risk assessment and for specifying the overall functional safety requirements of the complete IT system and he should select the functional safety level (SIL) of the IMD and/or IFLS when their safety function is part of the functional safety assessment in the IT system.
Elektrische Sicherheit in Niederspannungsnetzen bis AC 1 000 V und DC 1 500 V - Geräte zum Prüfen, Messen oder Überwachen von Schutzmaßnahmen - Teil 15: Anforderungen zur Funktionalen Sicherheit von Isolationsüberwachungsgeräten in IT-Systemen und von Einrichtungen zur Isolationsfehlersuche in IT-Systemen (IEC 61557-15:2014)
Sécurité électrique dans les réseaux de distribution basse tension de 1 000 V c.a. et 1 500 V c.c. - Dispositifs de contrôle, de mesure ou de surveillance de mesures de protection - Partie 15: Exigences de sécurité fonctionnelle pour les contrôleurs d'isolement de réseaux IT et les dispositifs de localisation de défauts d'isolement pour réseaux IT (CEI 61557-15:2014)
L'IEC 61557-15:2014 spécifie les exigences relatives à la sécurité fonctionnelle; elle se fonde sur la série de normes CEI 61508 pour la réalisation de contrôleurs d'isolement (CPI) tels que spécifiés dans la CEI 61557-8 et de systèmes de localisation de défauts d'isolement (DLD) conformes à la CEI 61557-9 et à la phase 10 du cycle de vie de la CEI 61508-1. Ces dispositifs assurent des fonctions relatives à la sécurité pour des réseaux IT. La présente partie de la CEI 61557 - traite uniquement des exigences de sécurité fonctionnelle visant à réduire le risque fonctionnel lors de l'utilisation des CPI et des DLD; - se limite aux risques résultant directement du dispositif proprement dit ou de plusieurs dispositifs CPI ou DLD collaborant au sein d'un réseau donné; et - vise à définir les fonctions de sécurité de base assurées par les dispositifs. La présente partie de la CEI 61557 - ne traite pas de la sécurité électrique selon la CEI 61010-1 et des exigences des normes CEI 61557-8 et CEI 61557-9; - ne couvre pas l'analyse des dangers et des risques d'un usage particulier de l'CPI ou de l'DLD; - n'identifie pas toutes les fonctions de sécurité de l'application où l'CPI ou l'DLD est utilisé; et ne couvre pas le processus de fabrication de l'CPI ou de l'DLD. La présente partie de la CEI 61557 doit être utilisée conjointement aux Parties 8 et 9. Les exigences de sécurité fonctionnelle dépendent de l'application et il convient d'en tenir compte dans le cadre de l'appréciation globale du risque de l'application spécifique. Le fournisseur des CPI et des DLD n'est pas responsable de l'application qui en est faite. Le concepteur de l'application est responsable de l'appréciation du risque et il lui incombe de spécifier les exigences globales de sécurité fonctionnelle de l'ensemble du réseau IT et il convient qu'il sélectionne le niveau de sécurité fonctionnelle (SIL) de l'CPI et/ou de l'DLD lorsque leur fonction de sécurité fait partie de l'évaluation de la sécurité fonctionnelle du réseau IT.
Električna varnost v nizkonapetostnih razdelilnih sistemih izmenične napetosti do 1 kV in enosmerne napetosti do 1,5 kV - Oprema za preskušanje, merjenje ali nadzorovanje zaščitnih ukrepov - 15. del: Zahteve za funkcionalno varnost za naprave za nadzorovanje izolacije in opremo za ugotavljanje mesta izolacijske okvare v sistemih IT (IEC 61557-15:2014)
Standard EN IEC 61557-15 določa zahteve za funkcionalno varnost in temelji na skupini standardov IEC 61508 za realizacijo naprav za nadzorovanje izolacije (IMD), kot je opredeljeno v standardu IEC 61557-8, in za sisteme za ugotavljanje mesta izolacijske okvare (IFLS) v skladu s standardom IEC 61557-9, v skladu s fazo 10 življenjske dobe IEC 61508-1. Te naprave zagotavljajo z varnostjo povezane funkcije za sisteme IT: Ta del standarda IEC 61557: – obravnava le zahteve za funkcionalno varnost, namenjene zmanjšanju funkcionalnega tveganja med uporabo IMD in IFLS; – je omejen na tveganja, ki izhajajo neposredno iz same naprave ali iz več IMD ali IFLS, ki skupaj delujejo v sistemu; – je namenjen opredelitvi osnovnih varnostnih funkcij, ki jih zagotavljajo naprave. Ta del standarda IEC 61557 ne: – obravnava električne varnosti v skladu s standardom IEC 61010-1 ter zahtev standardov IEC 61557-8 in IEC 61557-9; – obravnava analize nevarnosti in tveganj posamezne uporabe IMD ali IFLS; – opredeljuje vseh varnostnih funkcij za uporabo, v kateri se uporabljata IMD ali IFLS; – obravnava proizvodnega procesa IMD ali IFLS. Zahteve za funkcionalno varnost so odvisne od uporabe in naj bi se štele za del splošne ocene tveganja za posamezno uporabo. Dobavitelj IMD ali IFLS ni odgovoren za uporabo. Snovalec uporabe je odgovoren za oceno tveganja in opredelitev splošnih zahtev za funkcionalno varnost celotnega sistema IT ter naj bi izbral raven funkcionalne varnosti (SIL) IMD in/ali IFLS, kadar je njuna varnostna funkcija del ocene funkcionalne varnosti sistema IT.
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-oktober-2014
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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 15:
Functional safety requirements for insulation monitoring devices and for equipment for
insulation fault location in IT systems (IEC 61557-15:2014)
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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
Sécurité électrique dans les réseaux de distribution basse tension de 1 000 V c.a. et 1
500 V c.c. - Dispositifs de contrôle, de mesure ou de surveillance de mesures de
protection - Partie 15: Exigences de sécurité fonctionnelle pour les contrôleurs
d'isolement de réseaux IT et les dispositifs de localisation de défauts d'isolement pour
réseaux IT (CEI 61557-15:2014)
Ta slovenski standard je istoveten z: EN 61557-15:2014
ICS:
17.220.20 0HUMHQMHHOHNWULþQLKLQ Measurement of electrical
PDJQHWQLKYHOLþLQ and magnetic quantities
29.080.01 (OHNWULþQDL]RODFLMDQD Electrical insulation in
VSORãQR general
29.240.01 2PUHåMD]DSUHQRVLQ Power transmission and
GLVWULEXFLMRHOHNWULþQHHQHUJLMH distribution networks in
QDVSORãQR general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD EN 61557-15
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2014
ICS 17.220.20; 29.080.01; 29.240.01
English Version
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 15: Functional safety
requirements for insulation monitoring devices in IT systems and
equipment for insulation fault location in IT systems
(IEC 61557-15:2014)
Sécurité électrique dans les réseaux de distribution basse Elektrische Sicherheit in Niederspannungsnetzen bis AC 1
tension de 1 000 V c.a. et 1 500 V c.c. - Dispositifs de 000 V und DC 1 500 V - Geräte zum Prüfen, Messen oder
contrôle, de mesure ou de surveillance de mesures de Überwachen von Schutzmaßnahmen - Teil 15:
protection - Partie 15: Exigences de sécurité fonctionnelle Anforderungen zur Funktionalen Sicherheit von
pour les contrôleurs d'isolement de réseaux IT et les Isolationsüberwachungsgeräten in IT-Systemen und von
dispositifs de localisation de défauts d'isolement pour Einrichtungen zur Isolationsfehlersuche in IT-Systemen
réseaux IT (IEC 61557-15:2014)
(CEI 61557-15:2014)
This European Standard was approved by CENELEC on 2014-03-19. 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 CEN-CENELEC
Management Centre 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 CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2014 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 61557-15:2014 E
Foreword
The text of document 85/465/FDIS, future edition 1 of IEC 61557-15, prepared by IEC/TC 85 "Measuring
equipment for electrical and electromagnetic quantities" was submitted to the IEC-CENELEC parallel vote
and approved by CENELEC as EN 61557-15:2014.
The following dates are fixed:
• latest date by which the document has to be (dop) 2014-12-19
implemented at national level by
publication of an identical national
standard or by endorsement
(dow) 2017-03-19
• latest date by which the national
standards conflicting with the
document have to be withdrawn
This standard is to be used in conjunction with EN 61557-8 and EN 61557-9.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent rights.
This standard covers the Principle Elements of the Safety Objectives for Electrical Equipment Designed for
Use within Certain Voltage Limits (LVD).
Endorsement notice
The text of the International Standard IEC 61557-15:2014 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 60300-3-1 NOTE Harmonized as EN 60300-3-1.
1)
IEC 60335-1:2001 NOTE Harmonized as EN 60335-1:2002 (not modified).
1)
IEC 60335-1:2001/A1:2004 NOTE Harmonized as EN 60335-1:2002/A1:2004 (not modified).
1)
IEC 60335-1:2001/A2:2006 + Corr. 08-2006 NOTE Harmonized as EN 60335-1:2002/A2:2006 (not modified).
IEC 60364-4-41:2005 NOTE Harmonized as HD 60364-4-41:2007 (modified).
IEC 60364-5-55:2011 NOTE Harmonized as HD 60364-5-559:2012 (modified).
IEC 60364-7-710:2002 NOTE Harmonized as HD 60364-7-710:2012 (modified).
IEC 60730-1:2010 NOTE Harmonized as EN 60730-1:2011 (modified).
IEC 60812:2006 NOTE Harmonized as EN 60812:2006 (not modified).
IEC 61010-1:2010 + Corr. 05-2011 NOTE Harmonized as EN 61010-1:2010 (not modified).
IEC 61025 NOTE Harmonized as EN 61025.
IEC 61078 NOTE Harmonized as EN 61078.
IEC 61165 NOTE Harmonized as EN 61165.
IEC 61508-7:2010 NOTE Harmonized as EN 61508-7:2010 (not modified).
2)
IEC 61709:1996 NOTE Harmonized as EN 61709:1998 (not modified).
3)
IEC 61784-3:2007 NOTE Harmonized as EN 61784-3:2008 (not modified).
IEC 61800-5-2:2007 NOTE Harmonized as EN 61800-5-2:2007 (not modified).
IEC/ISO 31010:2009 NOTE Harmonized as EN 31010:2010 (not modified).
ISO 9001:2008 NOTE Harmonized as EN ISO 9001:2008 (not modified).
1)
Superseded by EN 60335-1:2012 (IEC 60335-1:2010, mod.)
2)
Superseded by EN 61709:2011 (IEC 61709:2011).
3)
Superseded by EN 61784-3:2010 (IEC 61784-3:2010).
- 3 - EN 61557-15:2014
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
NOTE 1 When an International Publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here: www.cenelec.eu
Publication Year Title EN/HD Year
IEC 61326-2-4 2012 Electrical equipment for measurement, EN 61326-2-4 2013
control and laboratory use -
EMC requirements -
Part 2-4: Particular requirements - Test
configurations, operational conditions and
performance criteria for insulation monitoring
devices according to IEC 61557-8 and for
equipment for insulation fault location according
to IEC 61557-9
IEC 61326-3-1 2008 Electrical equipment for measurement, EN 61326-3-1 2008
+ corr. August 2008 control and laboratory use -
EMC requirements -
Part 3-1: Immunity requirements for safety-
related systems and for equipment intended to
perform safety-related functions (functional
safety) - General industrial applications
IEC 61508-1 2010 Functional safety of EN 61508-1 2010
electrical/electronic/programmable electronic
safety-related systems -
Part 1: General requirements
IEC 61508-2 2010 Functional safety of EN 61508-2 2010
electrical/electronic/programmable electronic
safety-related systems -
Part 2: Requirements for
electrical/electronic/programmable electronic
safety-related systems
IEC 61508-3 2010 Functional safety of EN 61508-3 2010
electrical/electronic/programmable electronic
safety-related systems -
Part 3: Software requirements
IEC 61508-4 2010 Functional safety of EN 61508-4 2010
electrical/electronic/programmable electronic
safety-related systems -
Part 4: Definitions and abbreviations
IEC 61508-5 2010 Functional safety of EN 61508-5 2010
electrical/electronic/programmable electronic
safety-related systems -
Part 5: Examples of methods for the
determination of safety integrity levels
Publication Year Title EN/HD Year
IEC 61508-6 2010 Functional safety of EN 61508-6 2010
electrical/electronic/programmable electronic
safety-related systems -
Part 6: Guidelines on the application of
IEC 61508-2 and IEC 61508-3
IEC 61557-1 - Electrical safety in low voltage distribution EN 61557-1 -
systems up to 1 000 V a.c. and 1 500 V d.c. -
Equipment for testing, measuring or monitoring
of protective measures -
Part 1: General requirements
IEC 61557-8 - Electrical safety in low voltage distribution EN 61557-8 -
systems up to 1 000 V a.c. and 1 500 V d.c. -
Equipment for testing, measuring or monitoring
of protective measures -
Part 8: Insulation monitoring devices
for IT systems
IEC 61557-9 2009 Electrical safety in low voltage distribution EN 61557-9 2009
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
IEC 61557-15 ®
Edition 1.0 2014-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
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 15: Functional safety requirements for insulation monitoring devices in IT
systems and equipment for insulation fault location in IT systems
Sécurité électrique dans les réseaux de distribution basse tension de
1 000 V c.a. et 1 500 V c.c. – Dispositifs de contrôle, de mesure ou de
surveillance de mesures de protection –
Partie 15: Exigences de sécurité fonctionnelle pour les contrôleurs d'isolement
de réseaux IT et les dispositifs de localisation de défauts d'isolement pour
réseaux IT
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX XC
ICS 17.220.20, 29.080.01, 29.240.01 ISBN 978-2-8322-1406-0
– 2 – 61557-15 © IEC:2014
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 10
2 Normative references . 10
3 Terms, definitions and abbreviations . 11
3.1 Terms and definitions . 11
3.2 Abbreviations . 22
4 Definition of safety functions embedded in IMDs and IFLSs . 23
4.1 General . 23
4.2 Definition of safety functions . 23
4.2.1 Local insulation warning (LIW) . 23
4.2.2 Remote insulation warning (RIW) . 24
4.2.3 Local location warning (LLW) . 24
4.2.4 Remote location warning (RLW). 24
4.2.5 Remote enabling / disabling command (REDC) . 25
4.2.6 Local transformer monitoring warning (LTMW) . 25
5 Requirements on products implementing safety-related functions . 25
5.1 Requirement on non-safety-related functions . 25
5.2 Additional performance requirements for products implementing safety
functions . 26
5.2.1 General . 26
5.2.2 Additional performance requirements for IMDs complying with
SIL 1 or SIL 2 . 26
5.2.3 Additional performance requirements for IFLSs complying with
SIL 1 or SIL 2 . 26
6 Management of functional safety during the development lifecycle . 26
6.1 Management of functional safety for the IT system . 26
6.2 Use of IMDs and IFLSs in IT systems. 27
6.3 Safety lifecycle of IMDs and IFLSs in the realisation phase . 27
7 Management of functional safety during the realisation lifecycle of IMDs and
IFLSs. 28
7.1 General . 28
7.2 IMD and IFL design requirement specification (phase 10.1) . 29
7.2.1 Specification of functional safety requirements . 29
7.2.2 Provisions for the development of safety functions . 29
7.2.3 Verification plan for the development of safety functions . 30
7.2.4 Validation plan for the development of safety functions . 30
7.2.5 Planning of commissioning, installation and setting into
operation . 30
7.2.6 Planning of user documentation . 31
7.3 IMD and IFLS safety validation planning (phase 10.2) . 31
7.3.1 General . 31
7.3.2 Functional safety plan . 31
7.4 IMD and IFLS design and development (phase 10.3) . 32
7.4.1 General . 32
7.4.2 Design standards . 32
7.4.3 Realization . 32
61557-15 © IEC:2014 – 3 –
7.4.4 Safety integrity and fault detection . 32
7.4.5 Safety integrity level (SIL) assignment . 33
7.4.6 Hardware requirements . 33
7.4.7 Software requirements . 33
7.4.8 Review of requirements . 33
7.4.9 Requirements for the probability of dangerous failure on
demand (PFD) . 34
7.4.10 Failure rate data . 35
7.4.11 Diagnostic test interval . 35
7.4.12 Architectural constraints . 35
7.4.13 Estimation of safe failure fraction (SFF) . 37
7.4.14 Requirements for systematic safety integrity . 37
7.5 IMD and IFLS integration (phase 10.4) . 40
7.5.1 Hardware integration . 40
7.5.2 Software integration . 40
7.5.3 Modifications during integration . 40
7.5.4 Integration tests . 40
7.6 IMD and IFLS documentation related to installation, commissioning,
operation and maintenance procedures (phase 10.5) . 41
7.6.1 General . 41
7.6.2 Functional specification . 41
7.6.3 Compliance information . 41
7.6.4 Information for commissioning, installation, setting into
operation, operation and maintenance . 41
7.7 IMD and IFLS safety validation (phase 10.6) . 42
7.7.1 General . 42
7.7.2 Test . 42
7.7.3 Verification . 42
7.7.4 Validation . 43
7.7.5 EMC requirements . 43
8 Requirements for modifications. 44
8.1 General . 44
8.2 Modification request . 44
8.3 Impact analysis . 44
8.4 Authorization. 44
9 Proven in use approach . 44
Annex A (informative) Risk analysis and SIL assignment for IMDs and IFLSs . 45
A.1 General . 45
A.2 SIL assignment for IMDs and IFLSs . 47
A.3 Example of risk graph . 48
A.4 Alternative method of SIL assignment – quantitative method . 49
Annex B (informative) Examples for the determination of PFD, DC and SFF . 50
B.1 General . 50
B.2 Examples of IMD and IFLS architectures . 51
Annex C (informative) Failure rate databases . 52
C.1 General . 52
C.2 Failure rate references in current standards . 52
Annex D (informative) Guide to embedded software design and development . 53
D.1 General . 53
– 4 – 61557-15 © IEC:2014
D.2 Software element guidelines . 53
D.2.1 General . 53
D.2.2 Interface with system architecture. 53
D.2.3 Software specifications . 53
D.2.4 Pre-existent software . 54
D.2.5 Software design . 55
D.2.6 Coding . 55
D.3 Software development process guidelines . 55
D.3.1 Development process: software lifecycle . 55
D.3.2 Documentation: documentation management . 55
D.3.3 Configuration and software modification management . 56
D.3.4 Configuration and archiving management . 56
D.3.5 Software modifications management . 57
D.4 Development tools . 57
D.5 Reproduction of executable code production . 57
D.6 Software verification and validation . 57
D.7 General verification and validation guidelines . 57
D.8 Verification and validation review . 58
D.9 Software testing . 58
D.9.1 General validation . 58
D.9.2 Software specification verification: validation tests . 59
D.9.3 Software design verification: software integration tests . 59
D.9.4 Detailed design verification: module tests . 60
Annex E (informative) Information for the assessment of safety functions . 61
E.1 General . 61
E.2 Documentation management . 61
E.3 Documentation provided for conformity assessment . 61
E.4 Documentation of the development lifecycle. 63
E.5 Design documentation . 63
E.6 Documentation of verification and validation . 63
E.7 Test documentation . 63
E.8 Documentation of modifications . 63
E.9 Information for use . 63
Annex F (informative) Example of applications . 64
F.1 Overview. 64
F.2 Limitation in applications . 64
F.3 Typical applications covered by IEC 61557-15 . 64
F.3.1 General . 64
F.3.2 Local alarming . 64
F.3.3 Local transformer monitoring warning . 65
F.3.4 Alarming and processing of remote insulation warning and/or
remote location warning . 66
F.3.5 Automatic disconnection of the complete IT system in case of
a first insulation fault . 67
F.3.6 Automatic disconnection of an IT system sub-network . 69
F.3.7 Management of multiple source system (two incomers or of
incomer plus generator) . 71
F.3.8 Management of multiple source systems (two incomers or of
incomer plus generator – with a load shedder) . 72
Bibliography . 74
61557-15 © IEC:2014 – 5 –
Figure 1 – Relationship between IEC 61557-15 and related standards . 8
Figure 2 – Overall safety lifecycle applicable to an IT system . 27
Figure 3 – IMD and IFLS safety lifecycle (in realisation phase) . 28
Figure A.1 – Functional elements of an IT system and their relationship to the
definitions and abbreviations of the IEC 61508 series . 45
Figure A.2 – SIL assignment for IMDs and IFLSs . 47
Figure A.2 – Example of risk graph . 48
Figure B.1 – Flowchart for PFD, DC, SFF determination . 51
Figure F.1 – Local alarming, based on the systematic presence of one person and
based on a well-defined alarming management process. 65
Figure F.2 – Local transformer monitoring warning, based on the systematic presence
of a skilled person, and based on a well-defined alarming management process . 66
Figure F.3 – Alarming and processing of the remote insulation warning and/or the
remote location warning in a supervisory control system . 67
Figure F.4 – Disconnection of the complete IT system in case of insulation fault
detection . 68
Figure F.5 – Threshold 1 warning information and threshold 2 disconnection of the
complete IT system in case of an insulation fault detection . 69
Figure F.6 – Automatic disconnection of a faulty feeder via direct signal from the IFLS . 70
Figure F.7 – Automatic disconnection of a faulty feeder via a PLC . 71
Figure F.8 – Management of multiple source systems (two incomers or of one incomer
plus generator) . 72
Figure F.9 – Management of multiple source system (two incomers or of one incomer
plus generator, with a load shedder) . 73
Table 1 – Abbreviations with reference . 22
Table 2 – Safety integrity levels (SIL) and probability of a dangerous failure on
demand (PFD) of IMDs and IFLSs . 29
Table 3 – Hardware safety integrity: architectural constraints on type A and type B
safety-related subsystems . 37
Table A.1 – IT system risk analysis . 46
Table A.3 – Link between minimum risk reduction and SIL . 48
Table A.4 – Example of classifications according to risk graph Figure A.1 . 49
Table E.1 – Documentation to be provided . 62
– 6 – 61557-15 © IEC:2014
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
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 15: Functional safety requirements for insulation monitoring devices
in IT systems and equipment for insulation fault location in IT systems
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61557-15 has been prepared by IEC technical committee 85:
Measuring equipment for electrical and electromagnetic quantities.
The text of this standard is based on the following documents:
FDIS Report on voting
85/465/FDIS 85/470/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
61557-15 © IEC:2014 – 7 –
This part of IEC 61557 is to be used in conjunction with Part 8 and Part 9.
A list of all parts of the IEC 61557 series, published under the general title 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, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 8 – 61557-15 © IEC:2014
INTRODUCTION
IEC 61508 deals with functional safety, this topic being of upmost importance for safety
related systems. Functional safety may be applicable to IT systems where safety is based on
insulation monitoring devices (IMD) and insulation fault location systems (IFLS), and also on
additional safety related measures (e.g. circuit-breakers).
Insulation monitoring devices and insulation fault location systems comprise electrical and
electronic components and can comprise embedded software.
Product requirements for these devices are defined in IEC 61557-8 and IEC 61557-9. These
standards include elementary requirements which need to be taken into account for the
functional safety approach according to IEC 61557-15, but do not cover the whole range of
requirements which shall be fulfilled for the assignment of a defined level of functional safety
and for the respective validation.
IEC 61508 series covers basic aspects to be considered when electrical and electronic
systems are used to carry out safety functions. One of the major objectives of this series of
standards is to facilitate the development of international application or equipment standards
by the responsible technical committee. This will allow the technical committee to take the
special requirements of their application fully into account.
It is recognized that there is a great variety of applications of insulation monitoring devices
and of insulation fault location systems in IT systems. This part of IEC 61557 defines basic
safety functions as well as their related levels of functional safety (SIL) and defines feasible
measures and principles to develop and validate these devices and systems under functional
safety aspects.
Figure 1 shows the link between IEC 61557-15 and the relevant product, safety and EMC
standards as well as the link to the IEC 61508 series.
IEC 61557-1
General requirements
IEC 61557-8
Insulation monitoring
devices (IMD) IEC 61326-3-1 IEC 61557-15 IEC 61508
series
EMC requirements Functional
(functional safety) safety Functional
to be used in requirements safety
combination with for IMDs basic standard
IEC 61326-2-4 and IFLSs
IEC 61557-9
Insulation fault location
systems (IFLS)
IEC 0440/14
Figure 1 – Relationship between IEC 61557-15 and related standards
This part of IEC 61557 does not cover phases 1 to 9 and 11 to 16 of IEC 61508-1 for the
complete IT systems. In particular, this standard does not cover the use of IMDs and IFLSs in
customer application.
61557-15 © IEC:2014 – 9 –
NOTE 1 An insulation fault location system (IFLS) can consist of several devices according to IEC 61557-9:
insulation fault locator (IFL), locating current injector (LCI), locating current sensor (LCS), insulation monitoring
device (IMD) according to IEC 61557-8.
IMDs and IFLSs are not protective devices in general, but they are part of the protective
measures in IT systems. IMDs and IFLSs function as permanent monitoring of the insulation
resistance of the unearthed IT system and the localization of insulation faults in any part of
the system can be seen as safety functions which are part of the protective measures in an IT
system.
This part of IEC 61557 only applies to IMDs and IFLSs implementing SIL 1 and SIL 2 related
safety functions. Higher SIL levels are not specified in this standard because those levels are
generally not required for IMDs and IFLSs in IT systems.
Conformance to this standard may be required for IMDs or IFLSs when functional safety is
requested in the respective application within IT systems. However, it does not generally
dictate that for these devices, a defined level of functional safety according to this standard is
required.
NOTE 2 Examples of applications where functional safety can be requested depending on the risk analysis are:
– chemistry,
– mines,
– marine,
– hospital,
– photovoltaic farms,
– railway signalling systems,
– control systems ( e.g. in nuclear power plants),
– etc.
Examples of typical applications are provided in Annex F.
– 10 – 61557-15 © IEC:2014
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 15: Functional safety requirements for insulation monitoring devices
in IT systems and equipment for insulation fault location in IT systems
1 Scope
This part of IEC 61557 specifies requirements related to functional safety and is based on the
IEC 61508 standard series for the realization of insulation monitoring devices (IMD) as
specified in IEC 61557-8 and for insulation fault location systems (IFLS) according to
IEC 61557-9, according to phase 10 of the IEC 61508-1 lifecycle. These devices provide
safety related functions for IT systems.
This part of IEC 61557 is:
– concerned only with functional safety requirements intended to reduce the functional risk
during the use of IMDs and IFLSs;
– restricted to risks arising directly from the device itself or from several IMDs or IFLSs
working together in a system;
– intended to define the basic safety functions provided by the devices.
This part of IEC 61557 does not:
– deal with electrical safety according to IEC 61010-1 and the requirements of IEC 61557-8
and IEC 61557-9;
– cover the hazard and risk analysis of a particular use of the IMD or IFLS;
– identify all the safety functions for the application in which the IMD or IFLS is used;
– cover the IMD or IFLS manufacturing process.
Functional safety requirements depend on the application and should be considered as part of
the overall risk assessment of the specific application. The supplier of IMDs and IFLSs is not
responsible for the application. The application designer is responsible for the risk
assessment and for specifying the overall functional safety requirements of the complete IT
system and he should select the functional safety level (SIL) of the IMD and/or IFLS when
their safety function is part of the functional safety assessment in the IT system.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 61508-1:2010, Functional safety of electrical/electronic/programmable electronic safety-
related systems – Part 1: General requirements
IEC 61508-2:2010, Functional safety of electrical/electronic/programmable electronic safety-
related systems – Part 2: Requirements for electrical/electronic/programmable electronic
safety-related systems
61557-15 © IEC:2014 – 11 –
IEC 61508-3:2010, Functional safety of electrical/electronic/programmable electronic safety-
related systems – Part 3: Software requirements
IEC 61508-4:2010, Functional safety of electrical/electronic/programmable electronic safety-
related systems – Part 4: Definitions and abbreviations
IEC 61508-5:2010, Functional safety of electrical/electronic/programmable electronic safety-
related systems – Part 5: Examples of methods for the determination of safety integrity levels
IEC 61508-6:2010, Functional safety of electrical/electronic/programmable electronic safety-
related systems – Part 6: Guidelines on the application of IEC 61508-2 and IEC 61508-3
IEC 61557-1, Electrical safety in low voltage distribution systems up to 1 000 V a.c. and
1 500 V d.c. – Equipment
...
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