IEC TS 63397:2022
(Main)Photovoltaic (PV) modules - Qualifying guidelines for increased hail resistance
Photovoltaic (PV) modules - Qualifying guidelines for increased hail resistance
IEC TS 63397:2022 defines additional testing requirements for modules deployed under applications or in environments where PV modules are likely to be exposed to the impact of hailstones leading to higher stress beyond the scope of the IEC 61215 series. This document aims to assist in the selection of modules for deployment in specific regions that have a higher risk of hail damage and to provide tools for improving module design.
The contents of the corrigendum of July 2023 have been included in this copy.
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IEC TS 63397
®
Edition 1.0 2022-12
TECHNICAL
SPECIFICATION
colour
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Photovoltaic (PV) modules – Qualifying guidelines for increased hail resistance
IEC TS 63397:2022-12(en)
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IEC TS 63397
®
Edition 1.0 2022-12
TECHNICAL
SPECIFICATION
colour
inside
Photovoltaic (PV) modules – Qualifying guidelines for increased hail resistance
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.160 ISBN 978-2-8322-6194-1
Warning! Make sure that you obtained this publication from an authorized distributor.
® Registered trademark of the International Electrotechnical Commission
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– 2 – IEC TS 63397:2022 © IEC 2022
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Number and selection of test samples . 8
5 Test procedures . 8
5.1 General . 8
5.2 Visual inspection (MQT 01) . 8
5.3 Initial stabilization (MQT 19.1) . 8
5.4 Performance at STC (MQT 06.1) . 8
5.5 Performance at low irradiance (MQT 07) . 9
5.6 Insulation test (MQT 03) . 9
5.7 Wet leakage current test (MQT 15) . 9
5.8 Electroluminescence imaging . 9
5.9 Damp heat test (MQT 13) . 9
5.10 Hail test (HMQT 17) . 9
5.10.1 General . 9
5.10.2 Purpose . 9
5.10.3 Apparatus . 9
5.10.4 Procedure . 11
5.10.5 Final measurement . 12
5.10.6 Requirements . 12
5.11 Cyclic (dynamic) mechanical load test (MQT 20) . 13
5.12 Thermal cycling test (MQT 11) . 13
5.13 Humidity-freeze test (MQT 12) . 14
5.14 Final stabilization test (MQT 19.2) . 14
5.15 Requirements . 14
6 Report . 16
Annex A (informative) Hail maps . 18
Bibliography . 19
Figure 1 – Hail test equipment . 10
Figure 2 – Hail test example impact locations for wafer/cell based technologies and for
monolithic thin film technologies . 13
Figure 3 – Test flow . 15
Figure A.1 – Hailstorm map: Global . 18
Table 1 – Ice-ball masses and kinetic energy . 11
Table 2 – Impact locations . 12
Table 3 – Example of power loss reporting. 16
Table 4 – Schematic example of electroluminescence images prior and post stress
tests . 17
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IEC TS 63397:2022 © IEC 2022 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PHOTOVOLTAIC (PV) MODULES – QUALIFYING
GUIDELINES FOR INCREASED HAIL RESISTANCE
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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rights. IEC shall not be held responsible for identifying any or all such patent rights.
IEC TS 63397 has been prepared by IEC technical committee 82: Solar photovoltaic energy
systems. It is a Technical Specification.
The text of this Technical Specification is based on the following documents:
Draft Report on voting
82/2062/DTS 82/2090/RVDTS
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this Technical Specification is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
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– 4 – IEC TS 63397:2022 © IEC 2022
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The "colour inside" logo on the cover page of this document indicates that it
contains colours which are considered to be useful for the correct understanding of its
contents. Users should therefore print this document using a colour printer.
The contents of the corrigendum 1 (2023-07) have been included in this copy.
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IEC TS 63397:2022 © IEC 2022 – 5 –
INTRODUCTION
The hail test (MQT 17) of IEC 61215-2:2021, 4.17 examines PV modules for minimum hail
resistance by using spherical ice balls of a minimum diameter of 25 mm, or optionally larger.
The requirements after the test, as specified in IEC 61215-2, are:
a) no intermittent open-circuit fault detected during the test,
b) no evidence of major visual defects,
c) wet leakage current meeting the same requirements as for the initial measurements and the
power loss requirement of (Gate No. 2) IEC 61215-1:2021, 7.2.3.
The hail test (MQT 17) may cause visible damage detectable by MQT 01 as well as invisible
internal damage not detectable by MQT 01. Such invisible damage may also only be detected
by Gate No. 2 (power loss measurement after stress tests) if the damage is relatively large.
1
The IEC 61215 series [1] lays down requirements for the design qualification and type approval
of terrestrial photovoltaic modules suitable for long-term operation in open-air climates. It is
however not written with the intent to detect medium to long term performance losses caused
by hail to internal parts not visible to the naked eye. Such internal damages may be micro-cracks
of cells which over time can be propagated by other mechanical and thermo-mechanical
environmental stresses not addressed by the test flow of IEC 61215-1:2021, Figure 2.
The hail test (MQT 17) of IEC 61215-2:2021, 4.17 is sufficient for the generic design
qualification and type approval for applications and environments where PV modules are
unlikely to be exposed to severe hail exposure; however, a standardized test for applications
and environments where PV modules are likely to be exposed to higher hail stress is considered
useful.
IEC 61215-1:2021, Clause A.4 says: "Not all modules will experience extreme weather or
mishandling. Qualification testing that tests for performance retention under these
circumstances may lead to costly overdesign. … It is recommended to first develop and gain
experience with a TS related to hail resistance, module handling, and related performance
losses. Such a document should consider that thermal cycles might be more effective than
DML."
The share of generated photovoltaic energy globally is ever rising and the reliability and more
detailed prediction of generated power including energy loss is becoming more important for
the industry, in particular to the finance and insurance section of the industry.
The tests given in this document can differentiate the hail resistance of PV modules by exposing
samples to hail stress prior to the selected tests of IEC 61215-2:2021, Figure 2 and measure
the additional power loss to reference modules going through the same tests without hail stress.
The test sequence MQT 20 cyclic (dynamic) mechanical load test, MQT 11 thermal cycling test
and MQT 12 humidity freeze test post-hail stress tests used in this document are identical to
the test sequence 2 mechanical stress of IEC TS 63209-1:2021 [2]. The hail test HMQT 17 used
in this document contains changes to IEC 61215-2:2021, MQT 17 to improve accuracy,
comparability and repeatability of results. Additional information can be found in the Hail
Register [3]. This document, IEC TS 63397, aims to support in the selection of modules for
specific regions with higher risk to hail and the improvement of module design.
In addition to the power loss caused by the additional hail exposure the reporting section
includes electroluminescence images. The changes in these images alone are not always
indicative of power loss but may, together with the power measurement data, provide additional
insight.
—————————
1
Numbers in square brackets refer to the Bibliography.
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– 6 – IEC TS 63397:2022 © IEC 2022
Recent trends towards larger cell and module sizes may add to the risk of power loss caused
by hail. Recent, advanced cell interconnection technologies such as multi-wire technology aim
to limit power and energy loss due to cell cracks. On the system site there are trackers to bring
modules to their hail stow position to minimize impact.
Not all PV modules will be deployed to regions with increased risk of hail which is why it is not
planned to add these requirements to the IEC 61215 series. Annex A gives an example of a
global hail map with regions having a higher statistical average of hail exposure and hail ball
size.
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IEC TS 63397:2022 © IEC 2022 – 7 –
PHOTOVOLTAIC (PV) MODULES – QUALIFYING
GUIDELINES FOR INCREASED HAIL RESISTANCE
1 Scope
This document defines additional testing requirements for modules deployed under applications
or in environments where PV modules are likely to be exposed to the impact of hailstones
leading to higher stress beyond the scope of the IEC 61215 series.
The current safety standards of the IEC 61730 series [4] and design qualification and type
approval standards of the IEC 61215 series specify tests for the ability of PV modules to
withstand a defined hail impact. The requirements therein are the minimum for market entrance
and are not written to propagate potential cell damage caused by the hail impact by subsequent
mechanical and thermo-mechanical tests simulating the environmental stress that modules will
potentially be exposed to after hailstorms. In this document modules are initially exposed to
200 h of damp heat to account for some level of humidity and heat before the first hail exposure.
After that they are exposed to hail stresses and then to the selected thermo-mechanical stress
tests of sequence C of IEC 61215-1:2021, Figure 2. The power loss from these modules is then
compared to reference modules that have been through the same stress tests except the hail
stress.
Comparison of electroluminescence images and performance of both reference modules and
modules exposed to hail stress provides additional insight regarding hail resistance and
susceptibility.
This document aims to assist in the selection of modules for deployment in specific regions that
have a higher risk of hail damage and to provide tools for improving module design.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition
...
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