SIST EN IEC 60904-2:2024

Photovoltaic devices - Part 2: Requirements for photovoltaic reference devices

IEC 60904-2:2023 gives requirements for the classification, selection, packaging, marking, calibration and care of photovoltaic reference devices. This document applies to photovoltaic (PV) reference devices that are used to measure the irradiance of natural or simulated sunlight for the purpose of quantifying the electrical performance of photovoltaic devices (cells, modules and arrays). It does not cover photovoltaic reference devices for use under concentrated sunlight. This fourth edition cancels and replaces the third edition published in 2015. This edition includes the following significant technical changes with respect to the previous edition:
a) added calibration procedures for calibrating PV devices at maximum power by extending the respective Clauses 12 and 13;
b) revised requirements for mandatory measurement of spectral responsivity, temperature coefficients and linearity, depending on usage and allowing some measurements on equivalent devices;
c) revised requirements for built-in shunt resistor;
d) added requirements for traceability of calibration explicitly.

Photovoltaische Einrichtungen - Teil 2: Anforderungen an Referenz-Solarelemente

Dispositifs photovoltaïques - Partie 2: Exigences applicables aux dispositifs photovoltaïques de référence

L'IEC 60904-2:2023 donne les exigences relatives à la classification, à la sélection, au conditionnement, au marquage, à l’étalonnage et aux précautions d’utilisation des dispositifs photovoltaïques de référence. Le présent document s’applique aux dispositifs photovoltaïques (PV) de référence utilisés pour mesurer l’irradiance de la lumière solaire naturelle ou simulée afin de quantifier les performances électriques des dispositifs PV (cellules, modules et panneaux). Il ne couvre pas les dispositifs photovoltaïques de référence pour une utilisation sous éclairement solaire concentré. Cette quatrième édition annule et remplace la troisième édition parue en 2015. Cette édition inclut les modifications techniques majeures suivantes par rapport à l’édition précédente:
a) ajout de procédures d’étalonnage des dispositifs PV à la puissance maximale en développant les Articles 12 et 13) correspondants;
b) révision des exigences applicables au mesurage obligatoire de la sensibilité spectrale, des coefficients de température et de la linéarité, en fonction de l’usage et en permettant certains mesurages sur des dispositifs équivalents;
c) révision des exigences applicables aux résistances de shunt intégrées;
d) ajout d’exigences pour la traçabilité de l’étalonnage de manière explicite.

Fotonapetostne naprave - 2. del: Zahteve za referenčne sončne naprave

Standard IEC 60904-2:2023 podaja zahteve za klasifikacijo, izbiro, pakiranje, označevanje, umerjanje in oskrbo referenčnih sončnih naprav. Ta dokument se uporablja za referenčne sončne naprave, ki se uporabljajo za merjenje obsevanja naravne ali simulirane sončne svetlobe z namenom količinske opredelitve električne učinkovitosti fotonapetostnih (PV) naprav (celic, modulov in polj). Ne zajema referenčnih sončnih naprav za uporabo pod koncentrirano sončno svetlobo. Četrta izdaja razveljavlja in nadomešča tretjo izdajo, objavljeno leta 2015. Ta izdaja v primerjavi s prejšnjo vključuje naslednje pomembne tehnične spremembe:
a) z razširitvijo točk 12 in 13 so bili dodani postopki za umerjanje fotonapetostnih naprav pri največji moči;
b) zahteve za obvezno merjenje spektralne odzivnosti, temperaturnih koeficientov in linearnosti so bile spremenjene glede na uporabo, pri čemer je bilo nekaj meritev opravljenih na enakovrednih napravah;
c) zahteve za vgrajene odvodne upore so bile spremenjene;
d) dodane so bile zahteve izrecno za sledljivost umerjanja.

General Information

• Status: Published
• Publication Date: 10-Dec-2023
• ICS: 27.160 - Solar energy engineering
• Technical Committee: PVS - Solar photovoltaic energy systems
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 09-Nov-2023
• Due Date: 14-Jan-2024
• Completion Date: 11-Dec-2023
• Ref Project: EN IEC 60904-2:2023 - Photovoltaic devices - Part 2: Requirements for photovoltaic reference devices

Relations

• Revised: SIST EN 60904-2:2015 - Photovoltaic devices - Part 2: Requirements for reference solar devices
• Effective Date: 09-Dec-2021

Standards Content (Sample)

SLOVENSKI STANDARD
01-januar-2024
Fotonapetostne naprave - 2. del: Zahteve za referenčne sončne naprave
Photovoltaic devices - Part 2: Requirements for photovoltaic reference devices
Photovoltaische Einrichtungen - Teil 2: Anforderungen an Referenz-Solarelemente
Dispositifs photovoltaïques - Partie 2: Exigences applicables aux dispositifs
photovoltaïques de référence
Ta slovenski standard je istoveten z: EN IEC 60904-2:2023
ICS:
27.160 Sončna energija Solar energy engineering
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 60904-2

NORME EUROPÉENNE
EUROPÄISCHE NORM August 2023
ICS 27.160 Supersedes EN 60904-2:2015
English Version
Photovoltaic devices - Part 2: Requirements for photovoltaic
reference devices
(IEC 60904-2:2023)
Dispositifs photovoltaïques - Partie 2: Exigences Photovoltaische Einrichtungen - Teil 2: Anforderungen an
applicables aux dispositifs photovoltaïques de référence Referenz-Solarelemente
(IEC 60904-2:2023) (IEC 60904-2:2023)
This European Standard was approved by CENELEC on 2023-07-24. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN IEC 60904-2:2023 E

European foreword
The text of document 82/2127/FDIS, future edition 4 of IEC 60904-2, prepared by IEC/TC 82 "Solar
photovoltaic energy systems" was submitted to the IEC-CENELEC parallel vote and approved by
CENELEC as EN IEC 60904-2:2023.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2024-04-24
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2026-07-24
document have to be withdrawn
This document supersedes EN 60904-2:2015 and all of its amendments and corrigenda (if any).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 60904-2:2023 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standard indicated:
IEC 61215 (series) NOTE Approved as EN IEC 61215 (series)
IEC 61853-1 NOTE Approved as EN 61853-1
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
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.
NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod), the
relevant EN/HD applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cencenelec.eu.
Publication Year Title EN/HD Year
IEC 60891 - Photovoltaic devices - Procedures for EN IEC 60891 -
temperature and irradiance corrections to
measured I-V characteristics
IEC 60904-1 - Photovoltaic devices - Part 1: EN IEC 60904-1 -
Measurement of photovoltaic current-
voltage characteristics
IEC 60904-3 - Photovoltaic devices - Part 3: EN IEC 60904-3 -
Measurement principles for terrestrial
photovoltaic (PV) solar devices with
reference spectral irradiance data
IEC 60904-4 - Photovoltaic devices - Part 4: Photovoltaic EN IEC 60904-4 -
reference devices - Procedures for
establishing calibration traceability
IEC 60904-5 - Photovoltaic devices - Part 5: EN 60904-5 -
Determination of the equivalent cell
temperature (ECT) of photovoltaic (PV)
devices by the open-circuit voltage method
IEC 60904-7 - Photovoltaic devices - Part 7: Computation EN IEC 60904-7 -
of the spectral mismatch correction for
measurements of photovoltaic devices
IEC 60904-8 - Photovoltaic devices - Part 8: EN 60904-8 -
Measurement of spectral responsivity of a
photovoltaic (PV) device
IEC 60904-9 - Photovoltaic devices - Part 9: Classification EN IEC 60904-9 -
of solar simulator characteristics
IEC 60904-10 - Photovoltaic devices - Part 10: Methods of EN IEC 60904-10 -
linear dependence and linearity
measurements
IEC/TS 61836 - Solar photovoltaic energy systems - CLC/TS 61836 -
Terms, definitions and symbols

IEC 60904-2 ®
Edition 4.0 2023-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Photovoltaic devices –
Part 2: Requirements for photovoltaic reference devices

Dispositifs photovoltaïques –
Partie 2: Exigences applicables aux dispositifs photovoltaïques de référence

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.160 ISBN 978-2-8322-6948-0

– 2 – IEC 60904-2:2023 © IEC 2023
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 6
4 Selection of reference device . 8
4.1 General requirements . 8
4.2 Additional requirements for single reference cell in a multi-cell package . 8
4.3 Additional requirements for reference modules . 9
4.4 Requirements for built-in shunt resistors . 9
5 Temperature measurement . 10
6 Electrical connections . 10
7 Calibration . 10
7.1 General requirements . 10
7.2 Calibration value(s) . 10
7.3 Spectral responsivity . 11
7.4 Temperature coefficients . 11
7.5 Linearity . 11
8 Documentation and report . 11
8.1 General . 11
8.2 Device documentation . 11
8.3 Calibration report . 12
9 Marking . 12
10 Packaging . 12
10.1 Recommended packaging for use in natural sunlight . 12
10.2 Recommended packaging for use under solar simulators . 13
10.3 Single cell package . 13
11 Care of reference devices . 13
12 Usage of reference devices . 14
13 Calibration of secondary reference devices against a primary reference cell . 14
13.1 General . 14
13.2 Natural sunlight . 15
13.3 Simulated sunlight . 15
13.4 Test procedure . 15
13.5 Additional measurements . 17
13.5.1 Spectral responsivity . 17
13.5.2 Temperature coefficient(s) . 17
13.5.3 Linearity . 17
14 Calibration of working reference device against a secondary reference device . 17
Bibliography . 19

Figure 1 – Single cell package . 7
Figure 2 – Single reference cell in a multi-cell package . 8

IEC 60904-2:2023 © IEC 2023 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PHOTOVOLTAIC DEVICES –
Part 2: Requirements for photovoltaic reference devices

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
Publicly Available Specifications (PAS) and Guides (hereafter referred to as "IEC Publication(s)"). Their
preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
may participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence between
any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent
rights. IEC shall not be held responsible for identifying any or all such patent rights.
IEC 60904-2 has been prepared by IEC technical committee 82: Solar photovoltaic energy
systems. It is an International Standard.
This fourth edition cancels and replaces the third edition published in 2015. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) added calibration procedures for calibrating PV devices at maximum power by extending
the respective Clauses 12 and 13;
b) revised requirements for mandatory measurement of spectral responsivity, temperature
coefficients and linearity, depending on usage and allowing some measurements on
equivalent devices;
c) revised requirements for built-in shunt resistor;
d) added requirements for traceability of calibration explicitly.

– 4 – IEC 60904-2:2023 © IEC 2023
The text of this International Standard is based on the following documents:
Draft Report on voting
82/2127/FDIS 82/2151/RVD
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 International Standard 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.
A list of all parts in the IEC 60904 series, published under the general title Photovoltaic devices,
can be found on the IEC website.
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.

IEC 60904-2:2023 © IEC 2023 – 5 –
PHOTOVOLTAIC DEVICES –
Part 2: Requirements for photovoltaic reference devices

1 Scope
This part of IEC 60904 gives requirements for the classification, selection, packaging, marking,
calibration and care of photovoltaic reference devices.
This document applies to photovoltaic (PV) reference devices that are used to measure the
irradiance of natural or simulated sunlight for the purpose of quantifying the electrical
performance of photovoltaic devices (cells, modules and arrays). It does not cover photovoltaic
reference devices for use under concentrated sunlight.
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 60891, Photovoltaic devices – Procedures for temperature and irradiance corrections to
measured I-V characteristics
IEC 60904-1, Photovoltaic devices – Part 1: Measurement of photovoltaic current-voltage
characteristics
IEC 60904-3, Photovoltaic devices – Part 3: Measurement principles for terrestrial photovoltaic
(PV) solar devices with reference spectral irradiance data
IEC 60904-4, Photovoltaic devices – Part 4: Photovoltaic reference devices – Procedures for
establishing calibration traceability
IEC 60904-5, Photovoltaic devices – Part 5: Determination of the equivalent cell temperature
(ECT) of photovoltaic (PV) devices by the open-circuit voltage method
IEC 60904-7, Photovoltaic devices – Part 7: Computation of the spectral mismatch correction
for measurements of photovoltaic devices
IEC 60904-8, Photovoltaic devices – Part 8: Measurement of spectral responsivity of a
photovoltaic (PV) device
IEC 60904-9, Photovoltaic devices – Part 9: Classification of solar simulator characteristics
IEC 60904-10, Photovoltaic devices – Part 10: Methods of linear dependence and linearity
measurements
IEC TS 61836, Solar photovoltaic energy systems – Terms, definitions and symbols

– 6 – IEC 60904-2:2023 © IEC 2023
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC TS 61836 and the
following apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
calibration traceability
requirement for any PV reference device, to tie its calibration value
to SI units in an unbroken and documented chain of calibration transfers including stated
uncertainties
Note 1 to entry: Photovoltaic reference devices are distinguished by their position in a chain of calibration
traceability.
[SOURCE IEC 60904-4:2019, 3.6, modified – The term "traceability" has been replaced with
"calibration traceability" and Note 1 to entry has been replaced.]
3.2
reference device
traceably calibrated photovoltaic device
Note 1 to entry: Normally used to measure natural or simulated solar irradiance or to set solar simulator irradiance
levels for measuring the performance of other photovoltaic devices.
3.3
primary reference device
photovoltaic reference device with calibration based on a secondary standard for irradiance
traceable to SI units as defined in IEC 60904-4
Note 1 to entry: Typically, a PV cell is used as a reference device for the measurement of natural or simulated solar
irradiance.
Note 2 to entry: Primary references are normally used by calibration and testing laboratories to calibrate secondary
references.
Note 3 to entry: Normally calibrated at periodic intervals.
3.4
secondary reference device
photovoltaic reference device calibrated in natural or simulated sunlight against a primary
reference device
Note 1 to entry: Secondary references are normally used by calibration and testing laboratories to calibrate working
references, but also for daily routine measurements, in industrial production and in monitoring.
Note 2 to entry: Normally calibrated at periodic intervals.
3.5
working reference device
photovoltaic reference device calibrated in natural or simulated sunlight against a secondary
reference device
Note 1 to entry: Working references are normally used for daily routine measurements, in industrial production and
in monitoring.
Note 2 to entry: Normally calibrated at periodic intervals.

IEC 60904-2:2023 © IEC 2023 – 7 –
3.6
reference cell
reference device consisting of a single photovoltaic cell
Note 1 to entry: For practical reasons, such cells are small in surface area, and are usually mounted on a fixture
which ensures reproducibility in mounting, thermal control, electrical connections and protects the device. A typical
sample is sketched in Figure 1.
Note 2 to entry: Normally the reference cells are also provided with a protective window and embedded in an
encapsulant.
Note 3 to entry: Recommended use: as a laboratory primary, secondary and working reference.
Note 4 to entry: If the encapsulation system has been demonstrated to withstand long-term outdoor exposure,
applying test levels according to the IEC 61215 series [1], such reference cells can also be suitable to be used as a
monitoring device for long-term assessment of operational PV arrays.
Note 5 to entry: If the reference cell is provided with a protective window but without encapsulant, then it should
only be used when measuring the performance of other PV devices using direct beam natural or simulated sunlight.

Figure 1 – Single cell package
3.7
single reference cell in a multi-cell package
reference device consisting of a single photovoltaic cell mounted in a package such that frame,
encapsulation system, shape, size and spacing of the cells surrounding it are the same as in
the PV module to be tested
Note 1 to entry: The surrounding cells may be real or dummies that have the same optical properties.
3.8
reference module
reference device consisting of a photovoltaic module
Note 1 to entry: Recommended use: for measuring other modules in order to achieve correspondence of
dimensions, mechanical construction, optical properties and electrical circuitry of the reference module and test
module, so as to minimize discrepancies due to solar simulator spatial non-uniformity, internal reflections,
temperature distribution and spectral mismatch.
Note 2 to entry: As the diffuse component of natural sunlight and non-normal incidence of simulated sunlight interact
with encapsulants and back sheets of a PV module and influence the amount of irradiance which a particular cell
receives, it is recommended that reference devices used for measuring PV modules, sub-assemblies of PV modules
and PV arrays be encapsulated matching the mechanical and optical features of the device under test.

– 8 – IEC 60904-2:2023 © IEC 2023
3.9
built-in shunt resistor
resistor connected across the output terminals of photovoltaic devices including connection
wiring
Note 1 to entry: The resistor shunts the output of the photovoltaic device providing an output voltage to be measured
and avoiding user-provided means of establishing short-circuit condition.
Note 2 to entry: For details consult 4.4.
4 Selection of reference device
4.1 General requirements
Depending on their intended use, reference devices need to meet different requirements in
terms of their spectral responsivity, mechanical construction, optical properties, dimensions and
electrical circuit. The spectral responsivity of the reference device, for example, is determined
by the transmission of any protective window in front of the device and the spectral responsivity
of the device itself. Therefore, the overall spectral responsivity can be adapted by using suitable
filters as or in addition to the protective window.
Reference devices should be made using a PV technology that is known to be stable with time.
In particular, the calibration value should not change after the reference device has been
exposed to solar irradiation, device temperatures different from its calibration temperature
and/or extended storage in the dark. The photovoltaic characteristics of a reference device shall
be stable according to the requirements in Clause 11.
The reference device shall be constructed such that the photovoltaic performance parameters,
in particular short-circuit current and maximum power, can be measured. The only exception
are devices with a built-in shunt resistor, see 4.4.
4.2 Additional requirements for single reference cell in a multi-cell package
The dotted line in Figure 2 indicates the minimum acceptable size of a multi-cell package. For
other cell arrangements, such as half-cut cells, an analogous configuration applies.

Figure 2 – Single reference cell in a multi-cell package

IEC 60904-2:2023 © IEC 2023 – 9 –
4.3 Additional requirements for reference modules
Additional requirements apply to reference modules.
a) Bypass diodes:
• general reference modules, which are used to measure a range of module types and
geometries, should not contain bypass diodes. The presence or absence of bypass
diodes shall be noted and considered in conjunction with the measurement conditions,
in particular spatial non-uniformity of the irradiance on the module during measurement;
• for reference modules, which are intended to be matched to the module under test, the
number, type and connection of bypass diodes (if present) shall match those in the
module under test.
b) If they are made from discrete cells, these should be matched as follows depending on the
intended use of the reference module:
• if only the short-circuit current of the reference module will be used, the short-circuit
current of the individual cells should be matched to within ±1 %;
• if other parameters (such as maximum power) are used additionally or exclusively, both
the short-circuit current and the fill factor of the i
...