IEC 62548-1:2023

Photovoltaic (PV) arrays - Part 1: Design requirements

IEC 62548-1:2023 sets out design requirements for photovoltaic (PV) arrays including DC array wiring, electrical protection devices, switching and earthing provisions. The scope includes all parts of the PV array and final power conversion equipment (PCE), but not including energy storage devices, loads or AC or DC distribution network supplying loads. The object of this document is to address the design safety requirements arising from the particular characteristics of photovoltaic systems. This document also includes extra protection requirements of PV arrays when they are directly connected with batteries at the DC level.
This first edition cancels and replaces IEC 62548 published in 2016. This edition includes the following significant technical changes with respect to the previous edition:
a) Revised provisions for systems including DC to DC conditioning units.
b) Revision of mounting structure requirements.
c) Revised cable requirements.
d) Revision of Clause 6 on safety issues which includes provisions for protection against electric shock including array insulation monitoring and earth fault detection.
e) Revision of 7.2.7 and 7.3 with respect to isolation means.
f) Provisions for use of bifacial modules and modules mounted in non-optimal orientations.
g) New Annex F containing: KI factor calculations for bifacial and non-optimally oriented systems; anti-PID equipment and arc flash.

Groupes photovoltaïques (PV) - Partie 1: Exigences de conception

General Information

• Status: Published
• Publication Date: 06-Dec-2023
• ICS: 27.160 - Solar energy engineering
• Technical Committee: TC 82 - Solar photovoltaic energy systems
• Drafting Committee: WG 3 - TC 82/WG 3
• Current Stage: PPUB - Publication issued
• Start Date: 15-Dec-2023
• Completion Date: 07-Dec-2023

Relations

• Replaces: IEC 62548:2016 - Photovoltaic (PV) arrays - Design requirements
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 62548-1 ®
Edition 1.0 2023-12
INTERNATIONAL
STANDARD
colour
inside
Photovoltaic (PV) arrays –
Part 1: Design requirements
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IEC 62548-1 ®
Edition 1.0 2023-12
INTERNATIONAL
STANDARD
colour
inside
Photovoltaic (PV) arrays –
Part 1: Design requirements
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.160  ISBN 978-2-8322-7848-2

– 2 – IEC 62548-1:2023 © IEC 2023
CONTENTS
FOREWORD . 6
1 Scope . 8
2 Normative references . 8
3 Terms, definitions, symbols and abbreviated terms . 11
3.1 Terms and definitions . 11
3.2 Symbols . 17
3.3 Abbreviated terms . 20
4 Compliance with IEC 60364 series . 20
5 PV array system configuration . 21
5.1 General . 21
5.1.1 Functional configuration of a PV system . 21
5.1.2 PV system topologies . 21
5.1.3 Array electrical diagrams . 22
5.1.4 Use of PCE with multiple DC inputs . 28
5.1.5 PV arrays using DCUs . 28
5.1.6 Series-parallel configuration . 33
5.1.7 Batteries in systems . 33
5.1.8 Backfeed and reverse currents . 34
5.1.9 Considerations due to prospective fault current conditions within a PV
array . 34
5.1.10 Considerations due to operating temperature . 34
5.1.11 Performance issues . 35
5.1.12 Potential induced degradation. 36
5.1.13 Corrosion . 36
5.1.14 Mechanical design . 36
5.1.15 Mechanical loads on PV structures . 37
6 Safety issues . 39
6.1 General . 39
6.2 Protection against electric shock . 39
6.2.1 General . 39
6.2.2 Protective measure: double or reinforced insulation . 39
6.2.3 Protective measure: extra-low-voltage provided by SELV or PELV. 39
6.3 Protection against thermal effects . 39
6.3.1 General . 39
6.3.2 Protection against fire caused by arcs . 40
6.3.3 Protection against arc flash . 40
6.4 Protection against the effects of insulation faults . 40
6.4.1 General . 40
6.4.2 Segregation of PV circuits from other circuits . 41
6.4.3 Earth fault detection and indication requirements . 41
6.5 Protection against overcurrent . 47
6.5.1 General . 47
6.5.2 Requirement for overcurrent protection . 47
6.5.3 Requirements for overcurrent protection of circuits . 48
6.5.4 Overcurrent protection for PV systems connected to batteries . 50
6.5.5 Overcurrent protection location . 51
6.6 Protection against effects of lightning and overvoltage . 51

6.6.1 General . 51
6.6.2 Protection against overvoltage . 52
7 Selection and erection of electrical equipment . 53
7.1 General . 53
7.2 Component requirements . 54
7.2.1 General . 54
7.2.2 Current rating of PV circuits . 54
7.2.3 PV modules . 55
7.2.4 PV array and PV string combiner boxes . 56
7.2.5 Fuses . 57
7.2.6 Circuit breakers used for overcurrent protection . 57
7.2.7 Isolation means and isolation means with breaking capabilities . 58
7.2.8 Cables . 60
7.2.9 Plugs, sockets and connectors in PV circuits . 62
7.2.10 Wiring in combiner boxes . 63
7.2.11 Bypass diodes . 63
7.2.12 Blocking diodes . 64
7.2.13 Power conversion equipment (PCE) including DC conditioning units
(DCUs) . 64
7.3 Location and installation requirements . 65
7.3.1 Isolation means . 65
7.3.2 Earthing and bonding arrangements . 67
7.3.3 Wiring system . 70
8 Acceptance. 74
9 Operation/maintenance . 74
10 Marking and documentation . 74
10.1 Equipment marking . 74
10.2 Requirements for signs . 74
10.3 Identification of a PV installation . 74
10.4 Labelling of PV array and PV string combiner boxes . 74
10.5 Labelling of isolation means . 75
10.5.1 General . 75
10.5.2 PV array isolation means with breaking capabilities . 75
10.6 Warning sign for anti-PID equipment . 75
10.7 Documentation . 75
Annex A (informative) Examples of signs . 76
Annex B (informative) Examples of system earthing configurations in PV arrays . 77
Annex C (informative) Blocking diode . 80
C.1 General . 80
C.2 Use of blocking diodes to prevent overcurrent/fault current in arrays . 80
C.3 Examples of blocking diode use in fault situations . 80
C.3.1 General . 80
C.3.2 Short circuit in PV string . 80
C.4 Specification of blocking diode . 82
C.5 Heat dissipation design for blocking diode . 82
Annex D (informative) Arc fault detection and interruption in PV arrays . 84
Annex E (normative) DVC limits . 85

– 4 – IEC 62548-1:2023 © IEC 2023
Annex F (normative)  Determination of maximum voltage and maximum currents in PV
circuits . 86
F.1 U . 86
OC MAX
F.1.1 PV array maximum voltage . 86
F.1.2 PV strings constructed using DC conditioning units . 87
F.2 String maximum current .
...