Photovoltaic (PV) arrays - Earth fault protection equipment - Safety and safety-related functionality

IEC 63112:2021 is applicable to low voltage Photovoltaic Earth-Fault Protection Equipment (PV-EFPE) whose function is to detect, interrupt, and warn system operators of earth faults in solar photovoltaic arrays. This document specifies:
- the types and levels of the monitoring and protection functions that may be provided;
- the nature and timing of responses to earth faults;
- test methods for validating the monitoring and protection functions provided;
- requirements for functional safety and fault tolerance;
- requirements for product safety including construction, environmental suitability, markings, documentation, and testing.

Groupes photovoltaïques (PV) - Matériel de protection contre les défauts à la terre - Sécurité et fonctionnalités relatives à la sécurité

IEC 63112:2021 s'applique aux matériels de protection contre les défauts à la terre photovoltaïques (PV-EFPE) dont la fonction est de détecter, d'interrompre et de mettre en garde les opérateurs de réseau en cas de défauts à la terre dans les groupes photovoltaïques. Le présent document spécifie:
- les types et les niveaux des fonctions de surveillance et de protection qui peuvent être fournies;
- la nature et la chronologie des réponses aux défauts à la terre;
- les méthodes d'essai pour la validation des fonctions de surveillance et de protection fournies;
- les exigences en matière de sécurité fonctionnelle et de tolérance aux pannes;
- les exigences relatives à la sécurité du produit, y compris la construction, l'adaptation à l'environnement, les marquages, la documentation et les essais

General Information

Status
Published
Publication Date
21-Jun-2021
Current Stage
PPUB - Publication issued
Completion Date
22-Jun-2021
Ref Project

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IEC 63112
Edition 1.0 2021-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Photovoltaic (PV) arrays – Earth fault protection equipment – Safety and safety-
related functionality
Groupes photovoltaïques (PV) – Matériel de protection contre les défauts à la
terre – Sécurité et fonctionnalités relatives à la sécurité
IEC 63112:2021-06(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 63112
Edition 1.0 2021-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Photovoltaic (PV) arrays – Earth fault protection equipment – Safety and safety-
related functionality
Groupes photovoltaïques (PV) – Matériel de protection contre les défauts à la
terre – Sécurité et fonctionnalités relatives à la sécurité
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.160 ISBN 978-2-8322-9872-5

Warning! Make sure that you obtained this publication from an authorized distributor.

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® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – IEC 63112:2021 © IEC 2021
CONTENTS

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

INTRODUCTION ..................................................................................................................... 8

1 Scope .............................................................................................................................. 9

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

3 Terms, definitions, symbols and abbreviated terms ........................................................ 10

4 Requirements relating PV-EFP to system topology ........................................................ 12

4.1 General ................................................................................................................. 12

4.2 PV-EFP functions for different system topologies .................................................. 16

4.3 PV-EFPE control over host system operation ........................................................ 18

4.3.1 General ......................................................................................................... 18

4.3.2 Types of PV-EFPE requiring host system control ........................................... 18

4.3.3 Methods of control of the host system operation ............................................ 18

4.4 Disconnection under fault conditions ..................................................................... 19

4.4.1 General ......................................................................................................... 19

4.4.2 Disconnecting means ..................................................................................... 19

4.4.3 High impedance connections ......................................................................... 19

4.4.4 Indirect disconnection .................................................................................... 19

4.5 Systems with more than one sub-array (informative) ............................................. 20

4.5.1 General ......................................................................................................... 20

4.5.2 Isolated sub-arrays ........................................................................................ 20

4.5.3 Non-isolated sub-arrays ................................................................................. 20

5 PV array to earth insulation monitoring .......................................................................... 20

5.1 General ................................................................................................................. 20

5.2 Array insulation monitoring requirements .............................................................. 21

5.3 Array insulation fault response requirements......................................................... 21

5.4 Provisions for reset ............................................................................................... 22

5.5 Insulation monitoring function adjustability ............................................................ 22

6 PV array residual or earth current monitoring................................................................. 22

6.1 General ................................................................................................................. 22

6.2 Required PV-EFP current monitoring functions ..................................................... 22

6.3 Shock hazard current monitoring ........................................................................... 23

6.3.1 General ......................................................................................................... 23

6.3.2 Limits and response....................................................................................... 23

6.3.3 Provisions for reset ........................................................................................ 23

6.3.4 Shock hazard current monitoring – adjustability ............................................. 24

6.3.5 Fault tolerance of shock hazard current monitoring ........................................ 24

6.4 Fire hazard (continuous) current monitoring by electronic means .......................... 24

6.4.1 Overview ....................................................................................................... 24

6.4.2 General ......................................................................................................... 24

6.4.3 Settings and response ................................................................................... 24

6.4.4 Provisions for reset ........................................................................................ 25

6.4.5 Fire hazard current monitoring function adjustability ...................................... 25

6.4.6 Fault tolerance of fire hazard current monitoring by electronic means ............ 25

6.5 Fire hazard current monitoring by an overcurrent protective device in the

functional earthing conductor ................................................................................ 25

6.5.1 Overview ....................................................................................................... 25

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IEC 63112:2021 © IEC 2021 – 3 –

6.5.2 General ......................................................................................................... 25

6.5.3 Ratings .......................................................................................................... 26

6.5.4 Response ...................................................................................................... 26

6.5.5 Provisions for reset ........................................................................................ 26

6.5.6 Overcurrent protective device adjustability and replacement .......................... 26

7 Construction .................................................................................................................. 27

7.1 General ................................................................................................................. 27

7.2 Environmental considerations ............................................................................... 27

8 PV-EFP Fault Indication ................................................................................................ 28

8.1 General ................................................................................................................. 28

8.2 Integral fault indication .......................................................................................... 28

8.3 Remote fault indication ......................................................................................... 28

8.3.1 General ......................................................................................................... 28

8.3.2 Observability ................................................................................................. 28

8.3.3 Remote fault indication means ....................................................................... 28

8.4 Resetting of the fault indication ............................................................................. 28

9 Testing .......................................................................................................................... 29

9.1 General requirements for the tests in 9.2 through 9.5 ............................................ 29

9.1.1 Tests required ............................................................................................... 29

9.1.2 DC sources .................................................................................................... 29

9.1.3 AC sources .................................................................................................... 30

9.1.4 Laboratory conditions .................................................................................... 30

9.1.5 Monitoring the PV-EFPE means of control of the host system ........................ 30

9.1.6 Control of the PV-EFPE state ........................................................................ 30

9.1.7 Test setup ..................................................................................................... 31

9.2 Tests for PV array insulation monitoring functions ................................................. 32

9.2.1 Setup ............................................................................................................. 32

9.2.2 Sequence of tests .......................................................................................... 33

9.2.3 Test for R above setting during system start-up ......................................... 34

iso

9.2.4 Test for R below setting during system start-up ......................................... 34

iso

9.2.5 Test for R dropping below setting during operation .................................... 34

iso

9.2.6 Test for short circuit earth fault during system start-up .................................. 35

9.2.7 Test for short circuit earth fault during operation – non-earth-referenced

PV arrays ...................................................................................................... 35

9.2.8 Tests for PV array mid-point fault detection ................................................... 36

9.2.9 24 h timer test ............................................................................................... 36

9.3 Tests for residual or earth current monitoring functions: ........................................ 36

9.3.1 Setup ............................................................................................................. 36

9.3.2 Sequence of tests .......................................................................................... 37

9.3.3 Tests for shock hazard current monitoring ..................................................... 37

9.3.4 Tests for fire hazard current monitoring by electronic means ......................... 39

9.3.5 Fault-tolerance of shock hazard current monitoring and fire hazard

current monitoring by electronic means.......................................................... 41

9.3.6 Tests for fire hazard current monitoring by an overcurrent protective

device in the functional earthing conductor .................................................... 42

9.4 Test for short circuit earth fault during operation ................................................... 42

9.4.1 General ......................................................................................................... 42

9.4.2 Short circuit earth fault test procedure ........................................................... 42

9.4.3 Short circuit earth fault test pass/fail criteria .................................................. 42

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– 4 – IEC 63112:2021 © IEC 2021

9.5 Tests for coordination of PV-EFP functions ........................................................... 43

9.6 Product safety tests .............................................................................................. 44

10 Software or firmware performing safety critical functions ............................................... 44

10.1 General ................................................................................................................. 44

10.1.1 Overview ....................................................................................................... 44

10.1.2 Risk analysis ................................................................................................. 44

10.1.3 Integrated PV-EFPE ...................................................................................... 45

10.2 Evaluation methods .............................................................................................. 45

10.2.1 General ......................................................................................................... 45

10.2.2 Testing with features disabled ....................................................................... 45

10.2.3 Functional safety analysis .............................................................................. 45

11 Marking and documentation ........................................................................................... 46

11.1 Equipment markings ............................................................................................. 46

11.1.1 General ......................................................................................................... 46

11.1.2 Marking content ............................................................................................. 46

11.2 Installation and operating instructions ................................................................... 48

11.2.1 General ......................................................................................................... 48

11.2.2 General content ............................................................................................. 49

11.2.3 Information related to installation ................................................................... 49

11.2.4 Information related to operation ..................................................................... 51

11.2.5 Information related to maintenance ................................................................ 52

12 Routine (production) tests.............................................................................................. 52

12.1 General ................................................................................................................. 52

12.2 Routine dielectric tests .......................................................................................... 52

12.3 Routine EFP function tests .................................................................................... 52

12.3.1 General ......................................................................................................... 52

12.3.2 Shock hazard current monitoring ................................................................... 53

12.3.3 Electronic fire hazard current monitoring ........................................................ 53

12.3.4 Residual current device test function ............................................................. 53

12.3.5 PV array insulation monitoring function .......................................................... 53

Annex A (informative) Examples of system topologies with respect to PV Earth Fault

Protection ............................................................................................................................. 54

A.1 General ................................................................................................................. 54

A.2 Functionally earthed (FE) system with FE current monitoring ................................ 54

A.3 Functionally earthed (FE) system with a functionally earthed conductor fault ........ 55

A.4 Functionally earthed (FE) system with residual current monitoring ........................ 56

A.5 Non-separated system with residual current monitoring on PV+/- .......................... 57

A.6 Non-separated system with residual current monitoring on the AC side ................. 58

A.7 Non-earth-referenced system with continuous insulation monitoring ...................... 59

Annex B (informative) Background and rationale for PV Earth Fault Protection

requirements ......................................................................................................................... 60

B.1 Purpose ................................................................................................................ 60

B.2 PV earth faults – scope and meaning .................................................................... 60

B.3 PV-EFP goals ....................................................................................................... 61

B.4 PV-EFP challenges ............................................................................................... 61

B.4.1 Characteristics of PV systems that affect PV-EFP approaches ...................... 61

B.4.2 PV-EFP “blind spots” and coordination of protective measures ...................... 63

B.4.3 Relation between PV-EFP protection settings and PV system size ................ 65

B.5 Current and historical standards covering PV Earth Fault Protection ..................... 68

---------------------- Page: 6 ----------------------
IEC 63112:2021 © IEC 2021 – 5 –

B.5.1 General ......................................................................................................... 68

B.5.2 NFPA 70 – the US National Electrical Code (NEC) ........................................ 68

B.5.3 UL1741 and related documents ..................................................................... 68

B.5.4 VDE 0126-1-1 ................................................................................................ 69

B.5.5 IEC 62109-2 .................................................................................................. 70

B.5.6 IEC 60364-7-712 ........................................................................................... 71

B.5.7 IEC 62548 ..................................................................................................... 71

B.5.8 Conclusions ................................................................................................... 72

Bibliography .......................................................................................................................... 73

Figure 1 – Examples of functionally earthed system topologies ............................................. 14

Figure 2 – Examples of non-earth-referenced system topologies........................................... 15

Figure 3 – Examples of non-separated system topologies ..................................................... 16

Figure 4 – Example setup for PV-EFPE testing ..................................................................... 32

Figure 5 – Example setup for PV-EFPE testing of array mid-point faults ............................... 33

Figure A.1 – Functionally earthed (FE) system with current monitoring in the FE

conductor .............................................................................................................................. 54

Figure A.2 – Functionally earthed (FE) system with a functionally

earthed conductor fault ......................................................................................................... 55

Figure A.3 – Functionally earthed (FE) system with residual current monitoring .................... 56

Figure A.4 – Non-separated 3-phase system with residual current monitoring on PV+/- ........ 57

Figure A.5 – Non-separated 1-phase system with residual current monitoring

on the AC side ...................................................................................................................... 58

Figure A.6 – Non-earth-referenced system with continuous insulation monitoring.................. 59

Table 1 – PV-EFP functions based on system topology and earthing .................................... 17

Table 2 – Example PV array to earth insulation resistance limits ........................................... 21

Table 3 – Shock hazard – Sudden current change limits and response times ........................ 23

Table 4 – Example continuous current limits and response times .......................................... 24

Table 5 – Example trip current of overcurrent protection in the functional earthing

conductor .............................................................................................................................. 26

Table B.1 – Sudden change residual current limits ................................................................ 70

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– 6 – IEC 63112:2021 © IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PHOTOVOLTAIC (PV) ARRAYS –
EARTH FAULT PROTECTION EQUIPMENT –
SAFETY AND SAFETY-RELATED FUNCTIONALITY
FOREWORD

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International Standard IEC 63112 has been prepared by IEC technical committee 82: Solar

photovoltaic energy systems.
The text of this International Standard is based on the following documents:
FDIS Report on
...

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