IEC TS 63126:2020

IEC TS 63126 ®
Edition 1.0 2020-06
TECHNICAL
SPECIFICATION
colour
inside
Guidelines for qualifying PV modules, components and materials for operation
at high temperatures
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IEC TS 63126 ®
Edition 1.0 2020-06
TECHNICAL
SPECIFICATION
colour
inside
Guidelines for qualifying PV modules, components and materials for operation

at high temperatures
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.160 ISBN 978-2-8322-8396-7

– 2 – IEC TS 63126:2020 © IEC 2020
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Modifications to IEC 61215-2 . 9
4.1 General . 9
4.2 Hot-spot endurance test (MQT 09) . 9
4.3 UV preconditioning test (MQT 10) . 9
4.4 Thermal cycling test (MQT 11) . 9
4.5 Bypass diode testing (MQT 18) . 9
5 Modifications to IEC 61730 . 10
5.1 IEC 61730-1 . 10
5.2 IEC 61730-2 . 10
5.2.1 General . 10
5.2.2 Hot spot endurance test (MST 22) . 10
5.2.3 Bypass diode thermal test (MST 25) . 10
5.2.4 Materials creep test (MST 37) . 10
5.2.5 Thermal cycling test (MST 51) . 11
5.2.6 UV test (MST 54) . 11
5.2.7 Dry heat conditioning (MST 56) . 11
6 Modifications to component standards . 11
6.1 Polymeric packaging material testing requirements . 11
6.1.1 Test procedures for durability of polymer packaging materials . 11
6.1.2 Polymeric back sheets and front sheets . 11
6.2 Junction boxes according to IEC 62790 . 11
6.3 Connectors for DC application in photovoltaic systems according to
IEC 62852 . 12
6.4 Electric cables for photovoltaic systems with a voltage rating of 1,5 KV DC
according to IEC 62930 . 12
7 Test modification summary . 12
8 Reporting. 12
Annex A (informative) Determination of temperature level . 13
A.1 General . 13
A.2 Modelling . 13
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A.3 98 -percentile temperatures (T ) . 14
98th
A.4 Guidance on module temperature for several locations . 15
Bibliography . 18

Figure A.1 – Histogram and CDF of module temperature for Riyadh, Saudi Arabia. 15
Figure A.2 – Time series from the model for Riyadh . 15
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Figure A.3 – 98 -percentile temperature for an open-rack, or thermally unrestricted,
glass superstrate, polymer backsheet module . 16

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Figure A.4 – 98 -percentile temperature for a close-roof mounted glass superstrate,
polymer backsheet module . 16
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Figure A.5 – 98 -percentile temperature for insulated-back glass superstrate, polymer
backsheet module . 17

Table 1 – Test modification summary . 12

– 4 – IEC TS 63126:2020 © IEC 2020
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
GUIDELINES FOR QUALIFYING PV MODULES, COMPONENTS
AND MATERIALS FOR OPERATION AT HIGH TEMPERATURES

FOREWORD
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Technical Specifications are subject to review within three years of publication to decide
whether they can be transformed into International Standards.
IEC TS 63126, which is a Technical Specification, has been prepared by IEC technical
committee 82: Solar photovoltaic energy systems.

The text of this Technical Specification is based on the following documents:
Draft TS Report on voting
82/1662/DTS 82/1706A/RVDTS
Full information on the voting for the approval of this Technical Specification can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this publication will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific publication. At this date, the publication will be
• transformed into an International standard,
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication 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.

– 6 – IEC TS 63126:2020 © IEC 2020
INTRODUCTION
The IEC 61215 series, IEC 61730 series, IEC 62790 and IEC 62852 are considered suitable for
an environmental temperature range of at least -40 °C to + 40 °C and for modules operating in
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such conditions that a 98 percentile module operational temperature of 70 °C or less applies.
This environmental temperature range encompasses many locations and installation styles in
these locations. As an example, it has been determined that thermally unrestricted, or open-
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rack-style structures, in most cases do not result in 98 percentile module operational
temperatures exceeding 70 °C and as such, the originating standards are suitable as written.
th
percentile
Module operating temperatures exceeding 70 °C, on the other hand, at the 98
typically will occur with roof-parallel or building-integrated roof top applications in climates with
local environmental temperatures that exceed 40 °C.
This document is written for two purposes: to provide modified testing conditions for modules
that will be deployed in climates that have a higher environmental air temperature than 40 °C
and/or for module installation methods that restrict cooling, resulting in higher operational
temperatures than anticipated in the originating standards. This work will also aid in providing
an alternative definition of “rack mount” in the context of IEC 61215 series and IEC 61730
series. This term was initially used as a place holder to restrict the scope of PV module type
testing for those installation styles that permit open and unrestricted cooling from all surfaces
of a PV module. Now that the testing has matured there is a desire to refine definitions for the
range of applicability of these standards.
This document is intended to be used as an intermediate step to define high temperature
environment use requirements. These requirements are planned to be incorporated into
standards in the future. It is not necessarily cost effective for module materials to comply with
level 1 or level 2 requirements defined in this document, unless the module temperature is
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expected to exceed 70 °C at the 98 percentile. Module materials capable of temperature level
1 or temperature level 2 are expected to impose higher expectations of endurance and cost
than normal modules.
Component standard IEC 62930 is considered to be adequate for modules operating at high
temperatures without modification due to requiring cable to have a 120 °C or greater thermal
endurance at a 20 000 h correlation lifetime. Similarly, IEC 62979 is considered adequate for
bypass diode thermal runaway determination due to testing temperatures of 90 °C for roof-
mounted modules and 75°C for “rack mounted” modules.
Similar to electric cables, IEC 61730-1 requires a RTI, TI, or RTE of 90 °C or larger. A module
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operating in an environment and installation style resulting in a 98 percentile temperature of
70 °C requires a RTI, TI, or RTE safety factor of +20 °C to establish a 25-year lifetime when
the polymer has a minimum activation energy of 46 kJ/mol and the correlation lifetime is
20 000 h. This work applies that safety factor of +20 °C for polymer RTI, TI, or RTE when the
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98 percentile operating temperature is above 70 °C.
Finally, data from PV modules in hot climates and modelling were used to understand operating
temperatures and resulted in two categories of high temperature operation, temperature level 1
and temperature level 2. These categories are defined within this document and it is relevant
to indicate that level 2 temperatures were not found in field data, but may result from insulated
substrate modules on pitched roofs facing the sun when ambient air temperature exceeds
40 °C. This may be most consistent with building-integrated PV module roofs and to allow for
this possibility, the temperature level 2 category remains in this document.

GUIDELINES FOR QUALIFYING PV MODULES, COMPONENTS
AND MATERIALS FOR OPERATION AT HIGH TEMPERATURES

1 Scope
This document defines additional testing requirements for modules deployed under conditions
leading to higher module temperature which are beyond the scope of IEC 61215-1 and
IEC 61730-1 and the relevant component standards, IEC 62790 and IEC 62852. The testing
conditions specified in IEC 61215-2 and IEC 61730-2 (and the relevant component standards
IEC 62790 and IEC 62852) assumed that these standards are applicable for module
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deployment where the 98 percentile temperature (T ), that is the temperature that a module
98th
would be expected to equal or exceed for 175,2 h per year, is less than 70 °C.
NOTE 175,2 h represents 2 % of a total year as some thermal failure modes are a function of time at temperature
and not sensitive to day-only or night-only exposure.
This document defines two temperature regimes, temperature level 1 and temperature level 2,
which were designed considering deployment in environments with mounting configurations
such that the T is less than or equal to 80 °C for temperature level 1, and less than or equal
98th
to 90 °C for temperature level 2. This document provides recommended additional testing
conditions within the IEC 61215 series, IEC 61730 series, IEC 62790 and IEC 62852 for module
operation in temperature levels 1 and 2.
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 cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 61215-2:2016, Terrestrial photovoltaic (PV) modules – Design qualification and type
approval – Part 2: Test procedures
IEC 61730-1, Photovoltaic (PV) module safety qualification – Part 1: Requirements for
construction
IEC 61730-2, Photovoltaic (PV) module safety qualification – Part 2: Requirements for testing
IEC TS 61836, Solar photovoltaic energy systems – Terms, definitions and symbols
IEC 62788-1-7, Measurement procedures for materials used in photovoltaic modules – Part 1-
7: Encapsulants – Test procedure of optical durability
IEC TS 62788-2:2017, Measurement procedures for materials used in photovoltaic modules –
Part 2: Polymeric materials – Frontsheets and backsheets
IEC TS 62788-7-2, Measurement procedures for materials used in photovoltaic modules –
Part 7-2: Environmental exposures – Accelerated weathering tests of polymeric materials
IEC 62790, Junction boxes for photovoltaic modules – Safety requirements and tests

– 8 – IEC TS 63126:2020 © IEC 2020
IEC 62852, Connectors for DC-application in photovoltaic systems – Safety requirements and
tests
IEC 62930, Electric cables for photovoltaic s
...