IEC TR 63227:2020

Lightning and surge voltage protection for photovoltaic (PV) power supply systems

IEC TR 63227:2020 deals with the protection of PV power supply systems against detrimental effects of lightning strikes and surge voltages of atmospheric origin. In the event that a lightning and/or surge voltage protection is required to be erected, this document describes requirements and measures for maintaining the safety, functionality, and availability of the PV power supply systems.

General Information

• Status: Published
• Publication Date: 19-Oct-2020
• ICS: 27.160 - Solar energy engineering
• Technical Committee: TC 82 - Solar photovoltaic energy systems
• Current Stage: PPUB - Publication issued
• Start Date: 17-Nov-2020
• Completion Date: 20-Oct-2020

Standards Content (Sample)

IEC TR 63227 ®
Edition 1.0 2020-10
INTERNATIONAL
STANDARD
colour
inside
Lightning and surge voltage protection for photovoltaic (PV) power supply
systems
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IEC TR 63227 ®
Edition 1.0 2020-10
INTERNATIONAL
STANDARD
colour
inside
Lightning and surge voltage protection for photovoltaic (PV) power supply

systems
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.160 ISBN 978-2-8322-8950-1

– 2 – IEC TR 63227:2020 © IEC 2020
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Design principles . 8
4.1 Causes of damage and damages . 8
4.2 Galvanic coupling . 8
4.3 Magnetic field coupling . 9
4.4 Electric field coupling . 10
4.5 Risk management . 10
5 Lightning protection system (LPS) . 11
5.1 General . 11
5.2 External lightning protection . 12
5.3 Internal lightning protection . 14
5.4 Lightning equipotential bonding . 15
5.5 Lightning protection zone concept . 15
5.6 Selection of surge protective devices (SPDs) . 15
5.6.1 General . 15
5.6.2 Class I tested SPD, lightning current-carrying capacity I . 21
imp
5.6.3 Class II tested SPD, nominal impulse discharge surge current I . 23
n
5.7 Coordination of surge protective devices . 23
5.8 Selection of surge protective devices for a functionally earthed line
conductor . 23
6 Routing and shielding of cables/lines . 23
7 Functional earthing/lightning equipotential bonding . 25
8 Inspection and documentation . 26
Annex A (informative)  Shadowing . 27
Annex B (informative)  Tracking PV power supply system – External lightning
protection/down-conductors . 29
Annex C (informative) Practical example: lightning protection for a PV power supply
system installed on a saddle roof building . 30
Annex D (informative)  PV power supply system as a free-field system . 32
D.1 General . 32
D.2 Earth screw foundations . 32
D.3 Plate and strip or ring foundations . 33
D.4 Lightning current-carrying capacity of Class I tested SPDs for free-field
systems . 34
Annex E (informative) Metal roof and metal façade . 36
E.1 Metal roof . 36
E.2 Metal façades . 36
Bibliography . 38

Figure 1 – Examples of direct-axis components of voltage for galvanic coupling . 9
Figure 2 – Voltages induced in loops by the steepness of the lightning current . 10

Figure 3 – High resolution full climatology (HRFC) . 11
Figure 4 – Example for the design of the air-termination system for a PV power supply
system using the rolling sphere method . 12
Figure 5 – Maintaining the separation distance . 13
Figure 6 – Example for the design of the air-termination system for a PV power supply

system . 14
Figure 7 – Use of SPDs in PV power supply systems . 16
Figure 8 – Situation A) The surge voltage protection concept for a PV power supply
system on a building without external lightning protection . 17
Figure 9 – Situation B) Surge voltage protection concept for a PV power supply system
on a building with external lightning protection, the separation distance s is maintained . 17
Figure 10 – Situation C) Surge voltage protection concept for a PV power supply
system on a building with external lightning protection, the separation distance s is not
maintained . 18
Figure 11 – Situation C) Surge voltage protection concept for a PV power supply
system on a building with external lightning protection, the separation distance s is not
maintained, use of a shield able to carry the lightning current . 18
Figure 12 – Flow chart for the selection of protective measures . 20
Figure 13 – Example of a structure with two down-conductors of the external lightning
protection system. 22
Figure 14 – Reduction of the effects of induction by shielding and line routing . 24
Figure 15 – Example for the shielding of the generator main lines by closed metal
cable channels . 25
Figure 16 – Functional earthing of the module racks in case no external lightning
protection is available or the separation distance is not maintained . 26
Figure 17 – Lightning equipotential bonding at the module racks in case the separation
distance is not maintained . 26
Figure A.1 – Shadowing of a PV module by a lightning rod . 27
Figure A.2 – Minimum distance between the lightning rod or lightning line and the
PV module required to prevent an umbra . 28
Figure C.1 – Saddle roof building – Meshed air-termination systems of lightning
protection level III, the PV power supply system spans several meshes . 30
Figure C.2 – Example for the calculation of the separation distances for lightning
protection level III . 31
Figure D.1 – Connection of module tables to the earthing system for pile-driven
foundations and earth screw foundations . 33
Figure D.2 – Connection of module tables to the earthing system for strip foundations . 34
Figure D.3 – Earthing concept and arrangement of the SPDs for a free field . 35

Table 1 – Selection of the SPD test class (type) and minimum cross-section of the
equipotential bonding . 16
Table 2 – Selection of the minimum discharge capacity of voltage limiting SPDs of
Class I tested (voltage limiting type) or combined SPDs of Type 1 (series connection of
voltage limiting type and voltage switching type) . 21
Table 3 – Selection of the minimum discharge capacity of voltage switching class I
tested SPDs (voltage switching) or combined class I tested SPDs (parallel connection
of voltage limiting and voltage switching) . 22
Table A.1 – Minimum distance of air-termination systems required to avoid an umbra . 28
Table D.1 – Minimum discharge capacity of voltage limiting or combined Class I tested
SPDs and voltage switching type class I tested SPDs . 35

– 4 – IEC TR 63227:2020 © IEC 2020
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LIGHTNING AND SURGE VOLTAGE PROTECTION
FOR PHOTOVOLTAIC (PV) POWER SUPPLY SYSTEMS

FOREWORD
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