IEC 60904-7:2008

Photovoltaic devices - Part 7: Computation of the spectral mismatch correction for measurements of photovoltaic devices

IEC 60904-7:2008 describes the procedure for correcting the bias error introduced in the testing of a photovoltaic device, caused by the mismatch between the test spectrum and the reference spectrum and by the mismatch between the spectral responses (SR) of the reference cell and of the test specimen. The procedure applies only to photovoltaic devices linear in SR as defined in IEC 60904-10. This procedure is valid for single junction devices but the principle may be extended to cover multijunction devices. This new edition includes the following changes with respect to the previous one: description of when it is necessary to use the method and when it may not be needed; addition of new clauses.

Dispositifs photovoltaïques - Partie 7: Calcul de la correction de désadaptation des réponses spectrales dans les mesures de dispositifs photovoltaïques

La CEI 60904-7:2008 décrit la procédure pour corriger l'erreur de justesse de mesure introduite dans l'essai d'un dispositif photovoltaïque, due d'une part à la désadaptation du spectre pour l'essai et du spectre de référence, et d'autre part à la désadaptation entre les réponses spectrales de la cellule de référence et du spécimen en essai. La procédure s'applique seulement aux dispositifs photovoltaïques linéaires en réponses spectrales tels que définis dans la CEI 60904-10. Cette procédure est valable pour les dispositifs à jonction unique mais le principe peut être étendu aux dispositifs à multi-jonctions. Cette nouvelle édition contient les différences suivantes par rapport à l'édition précédente: une description indiquant quand il faut utiliser la méthode et quand elle n'est pas nécessaire; ajout de nouveaux paragraphes.

General Information

• Status: Published
• Publication Date: 25-Nov-2008
• ICS: 27.160 - Solar energy engineering
• Technical Committee: TC 82 - Solar photovoltaic energy systems
• Drafting Committee: WG 2 - TC 82/WG 2
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 20-Aug-2019

Relations

• Revised: IEC 60904-7:2019 - Photovoltaic devices - Part 7: Computation of the spectral mismatch correction for measurements of photovoltaic devices
• Effective Date: 05-Sep-2023
• Revises: IEC 60904-7:1998 - Photovoltaic devices - Part 7: Computation of spectral mismatch error introduced in the testing of a photovoltaic device
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 60904-7
Edition 3.0 2008-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Photovoltaic devices –
Part 7: Computation of the spectral mismatch correction for measurements of
photovoltaic devices
Dispositifs photovoltaïques –
Partie 7: Calcul de la correction de désadaptation des réponses spectrales dans
les mesures de dispositifs photovoltaïques

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IEC 60904-7
Edition 3.0 2008-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Photovoltaic devices –
Part 7: Computation of the spectral mismatch correction for measurements of
photovoltaic devices
Dispositifs photovoltaïques –
Partie 7: Calcul de la correction de désadaptation des réponses spectrales dans
les mesures de dispositifs photovoltaïques

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
K
CODE PRIX
ICS 27.160 ISBN 978-2-88910-324-9
– 2 – 60904-7 © IEC:2008
CONTENTS
FOREWORD.3

1 Scope and object.5

2 Normative references .5

3 Description of method.6

4 Apparatus.7

5 Determination of spectral response .7

6 Determination of test spectrum .7

7 Determination of the spectral mismatch factor .8
8 Report .9
Bibliography.10

60904-7 © IEC:2008 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
PHOTOVOLTAIC DEVICES –
Part 7: Computation of the spectral mismatch correction

for measurements of photovoltaic devices

FOREWORD
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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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.
International Standard IEC 60904-7 has been prepared by IEC technical committee 82: Solar
photovoltaic energy systems.
The text of this standard is based on the following documents:
FDIS Report on voting
82/540/FDIS 82/547/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This third edition cancels and replaces the second edition published in 1998. It constitutes a
technical revision. The main changes with respect to the previous edition are listed below:
• the title has been modified in order to better reflect the purpose of the standard (changed
from “mismatch error” to “mismatch correction”);

– 4 – 60904-7 © IEC:2008
• formulae are now accompanied by explanatory text;

• Clause 3 “Description of method” now describes when it is necessary to use the method
and when it may not be needed. It describes what data must be collected before the

mismatch correction can be calculated;

• Clauses 4, 5 and 6 have added;

• the formula for the mismatch correction has been corrected.

This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

A list of all parts of 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 publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
60904-7 © IEC:2008 – 5 –
PHOTOVOLTAIC DEVICES –
Part 7: Computation of the spectral mismatch correction

for measurements of photovoltaic devices

1 Scope and object
This part of IEC 60904 describes the procedure for correcting the bias error introduced in the
testing of a photovoltaic device, caused by the mismatch between the test spectrum and the
reference spectrum and by the mismatch between the spectral responses (SR) of the
reference cell and of the test specimen. The procedure applies only to photovoltaic devices
linear in SR as defined in IEC 60904-10. This procedure is valid for single junction devices
but the principle may be extended to cover multijunction devices.
The purpose of this standard is to give guidelines for the correction of measurement bias,
should there be a mismatch between both the test spectrum and the reference spectrum and
between the reference device SR and the test specimen SR.
Since a PV device has a wavelength-dependent response, its performance is significantly
affected by the spectral distribution of the incident radiation, which in natural sunlight varies
with several factors such as location, weather, time of year, time of day, orientation of the
receiving surface, etc., and with a simulator varies with its type and conditions. If the
irradiance is measured with a thermopile-type radiometer (that is not spectrally selective) or
with a reference solar cell, the spectral irradiance distribution of the incoming light must be
known to make the necessary corrections to obtain the performance of the PV device under
the reference solar spectral distribution defined in IEC 60904-3.
If a reference PV device or a thermopile type detector is used to measure the irradiance then,
following the procedure given in this standard, it is possible to calculate the spectral mismatch
correction necessary to obtain the short-circuit current of the test PV device under the
reference solar spectral irradiance distribution included in Table 1 of IEC 60904-3 or any
other reference spectrum. If the reference PV device has the same relative spectral response
as the test PV device then the reference device automatically takes into account deviations of
the real light spectral distribution from the standard spectral distribution, and no further
correction of spectral bias errors is necessary. In this case, location and weather conditions
are not critical when the reference device method is used for outdoor performance
measurements provided both reference cell and test PV device have the same relative
spectral response. Also, for identical relative SR’s, the spectral classification
...