SIST EN 61829:2016

SLOVENSKI STANDARD
SIST EN 61829:2016
01-april-2016
1DGRPHãþD
SIST EN 61829:2001
Fotonapetostno polje iz kristalnega silicija – Merjenje karakteristike I-U na mestu
vgradnje
Crystalline silicon photovoltaic (PV) array - On-site measurement of I-V characteristics
Champ de modules photovoltaïques (PV) au silicium cristallin - Mesure sur site des
caractéristiques I-V
Ta slovenski standard je istoveten z: EN 61829:2016
ICS:
27.160 6RQþQDHQHUJLMD Solar energy engineering
SIST EN 61829:2016 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 61829:2016

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SIST EN 61829:2016


EUROPEAN STANDARD EN 61829

NORME EUROPÉENNE

EUROPÄISCHE NORM
February 2016
ICS 27.160 Supersedes EN 61829:1998
English Version
Photovoltaic (PV) array - On-site measurement of current-
voltage characteristics
(IEC 61829:2015)
Champ de modules photovoltaïques (PV) - Mesurage sur Photovoltaische (PV) Modulgruppen - Messen
site des caractéristiques courant-tension der Strom-/Spannungskennlinien am Einsatzort
(IEC 61829:2015) (IEC 61829:2015)
This European Standard was approved by CENELEC on 2015-11-26. 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.


European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2016 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
 Ref. No. EN 61829:2016 E

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SIST EN 61829:2016
EN 61829:2016
European foreword
The text of document 82/1008/FDIS, future edition 2 of IEC 61829, prepared by IEC/TC 82 “Solar
photovoltaic energy systems" was submitted to the IEC-CENELEC parallel vote and approved by
CENELEC as EN 61829:2016.

The following dates are fixed:
(dop) 2016-08-26
• latest date by which the document has to be
implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2019-02-26
standards conflicting with the
document have to be withdrawn

This document supersedes EN 61829:1998.

Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such
patent rights.

Endorsement notice
The text of the International Standard IEC 61829:2015 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 standards indicated:

IEC 60904-5 NOTE Harmonized as EN 60904-5.
IEC 61853-1:2011 NOTE Harmonized as EN 61853-1:2011 (not modified).
ISO/IEC 17025 NOTE Harmonized as EN ISO/IEC 17025.
2

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SIST EN 61829:2016
EN 61829:2016
Annex ZA
(normative)

Normative references to international publications
with their corresponding European publications

The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.

NOTE 1 When 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.cenelec.eu

Publication Year Title EN/HD Year

IEC 60891 -  Photovoltaic devices - Procedures for EN 60891 -
temperature and irradiance corrections to
measured I-V characteristics
IEC 60904-1 -  Photovoltaic devices - EN 60904-1 -
Part 1: Measurement of photovoltaic
current-voltage characteristics
IEC 60904-2 -  Photovoltaic devices - EN 60904-2 -
Part 2: Requirements for photovoltaic
reference devices
IEC 60904-3 -  Photovoltaic devices - EN 60904-3 -
Part 3: Measurement principles for
terrestrial photovoltaic (PV) solar devices
with reference spectral irradiance data
IEC 60904-4 -  Photovoltaic devices - EN 60904-4 -
Part 4: Reference solar devices -
Procedures for establishing calibration
traceability
IEC 60904-7 -  Photovoltaic devices - EN 60904-7 -
Part 7: Computation of the spectral
mismatch correction for measurements of
photovoltaic devices
IEC 60904-10 -  Photovoltaic devices - EN 60904-10 -
Part 10: Methods of linearity measurement

3

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SIST EN 61829:2016

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SIST EN 61829:2016



IEC 61829

®


Edition 2.0 2015-10




INTERNATIONAL



STANDARD




NORME



INTERNATIONALE











Photovoltaic (PV) array – On-site measurement of current-voltage characteristics



Champ de modules photovoltaïques (PV) – Mesurage sur site des caractéristiques


courant-tension

















INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE


INTERNATIONALE




ICS 27.160 ISBN 978-2-8322-2966-8



Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

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SIST EN 61829:2016
– 2 – IEC 61829:2015 © IEC 2015
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Apparatus . 7
4.1 Irradiance measurements in natural sunlight . 7
4.2 Module temperature measurements . 8
4.3 Electrical measurements . 8
5 Measurement procedure . 9
5.1 Choose and record appropriate conditions for measurement . 9
5.2 Clean the modules . 9
5.3 Check for shading . 9
5.4 Confirm uniformity of irradiance over the test array . 10
5.5 Mount the reference device . 10
5.6 Prepare to measure the array temperature . 10
5.7 Disconnect the array . 11
5.8 Connect the measurement system to the array to be measured . 11
5.9 Record electrical data and measurement conditions . 11
5.10 Record spectral data . 12
5.11 Typical and extreme module selection . 12
6 Analysis . 13
6.1 Adjust the measured irradiance for any deviation from reference conditions . 13
6.2 Compute the average temperature of the array under test . 13
6.3 Compute the junction temperature . 14
6.4 Translate the measurement to the desired test condition . 14
6.5 Correct for soiling losses . 14
7 Test report . 14
Annex A (informative) Reference values and reference device . 16
A.1 Reference test conditions (RTC) . 16
A.2 Standard test conditions (STC) . 16
A.3 Reference device . 16
Bibliography . 17

Figure 1 – Examples of extreme and central modules . 13

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SIST EN 61829:2016
IEC 61829:2015 © IEC 2015 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

PHOTOVOLTAIC (PV) ARRAY –
ON-SITE MEASUREMENT OF CURRENT-VOLTAGE CHARACTERISTICS

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.
International Standard IEC 61829 has been prepared by IEC technical committee 82: Solar
photovoltaic energy systems.
This second edition cancels and replaces the first edition published in 1995. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) it addresses many outdated procedures;
b) it accommodates commonly used commercial I-V curve tracers;
c) it provides a more practical approach for addressing field uncertainties;
d) it removes and replaces procedures with references to other updated and pertinent
standards, including the IEC 60904 series, and IEC 60891.

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The result is a much more practical and useful standard.
The text of this standard is based on the following documents:
FDIS Report on voting
82/1008/FDIS 82/1041/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 publication 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
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

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SIST EN 61829:2016
IEC 61829:2015 © IEC 2015 – 5 –
INTRODUCTION
The performance of photovoltaic (PV) systems over their decades-long life time is determined
by comparing measured power production with the expected production as estimated from
recorded weather conditions. Continuous measurements of system- or subsystem-level
operating output can detect underperforming arrays but are not well suited for tracking
degradation with any accuracy, or for identifying the weaknesses or failure modes that may
exist within the array. Field I-V curve measurements offer a practical method of in situ
benchmarking or troubleshooting for modules, strings and arrays. This International Standard
specifies methods and approaches for field I-V curve measurements and calculations, and
includes guidance for addressing the uncertainties associated with measurement devices and
array configurations. Consistent and proper application of I-V curve measurement procedures
helps to ensure that a PV system’s performance is adequately characterized over time.

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PHOTOVOLTAIC (PV) ARRAY –
ON-SITE MEASUREMENT OF CURRENT-VOLTAGE CHARACTERISTICS



1 Scope
This International Standard specifies procedures for on-site measurement of flat-plate
photovoltaic (PV) array characteristics, the accompanying meteorological conditions, and use
of these for translating to standard test conditions (STC) or other selected conditions.
Measurements of PV array current-voltage (I-V) characteristics under actual on-site conditions
and their translation to reference test conditions (RTC) can provide:
• data for power rating or capacity testing;
• verification of installed array power performance relative to design specifications;
• detection of possible differences between on-site module characteristics and laboratory or
factory measurements;
• detection of possible performance degradation of modules and arrays with respect to on-
site initial data;
• detection of possible module or array failures or poor performance.
For a particular module, on-site measurements translated to STC can be directly compared
with results previously obtained in a laboratory or factory for that module. Corrections for
differences in the spectral or spatial response of the reference devices may need to be
assessed as specified in IEC 60904.
On-site array measurements are affected by diode, cable, and mismatch losses, soiling and
shading, degradation due to aging, and other uncontrolled effects. Therefore, they are not
expected to be equal to the product of the number of modules and the respective module
data.
If a PV array is formed with sub-arrays of different tilt, orientation, technology, or electrical
configuration, the procedure specified in this International Standard is applied to each unique
PV sub-array of interest.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. 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 60904-2, Photovoltaic devices – Part 2: Requirements for photovoltaic reference devices
IEC 60904-3, Photovoltaic devices – Part 3: Measurement principles for terrestrial
photovoltaic (PV) solar devices with reference spectral irradiance data

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SIST EN 61829:2016
IEC 61829:2015 © IEC 2015 – 7 –
IEC 60904-4, Photovoltaic devices – Part 4: Reference solar devices – Procedures for
establishing calibration traceability
IEC60904-7, Photovoltaic devices – Part 7: Computation of the spectral mismatch correction
for measurements of photovoltaic devices
IEC 60904-10, Photovoltaic devices – Part 10: Methods for linearity measurements
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
pyranometer
radiometer normally used to measure global irradiance on a horizontal plane
Note 1 to entry: A pyranometer can also be used to measure diffuse irradiance when used with a shade ring or
disc.
Note 2 to entry: A pyranometer can also be used to measure total irradiance on an inclined plane, which would
include radiation reflected from the foreground.
[SOURCE: IEC TS 61836:2007, 3.5.7 b)]
3.2
radiometer
instrument for measuring the intensity of solar irradiance
Note 1 to entry: See also IEC 60050-845:1987, 845-05-06.
Note 2 to entry: Commonly, a radiometer is a thermal instrument using thermocouples or thermopiles and is
independent of wavelength.
[SOURCE: IEC TS 61836:2007, 3.5.7]
3.3
spectroradiometer
instrument used to measure spectral irradiance distribution of an incident radiation as a
function of wavelength
[SOURCE: IEC TS 61836:2007, 3.5.7 d)]
4 Apparatus
4.1 Irradiance measurements in natural sunlight
The irradiance measurements shall be made using a PV reference device packaged and
calibrated in conformance with IEC 60904-2 or with a pyranometer. PV reference devices
shall have spectral matching addressed by one of the following methods.
a) The reference device is spectrally matched to the modules in the array under test.
b) A spectral mismatch correction should be performed in conformance with IEC 60904-7.
The reference device shall be linear in short-circuit current as defined in IEC 60904-10
over the irradiance range of interest.
c) If spectral measurements are not practical, uncertainties associated with the irradiance
measurement and specific sensors used should be reported as part of the analysis.
Measurements should be completed under clear-sky conditions with the nearest clouds at

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least 15° from the sun and the sensor mounted in the plane of the items under test as
discussed elsewhere.
To be considered spectrally matched, a reference device shall be constructed using the same
cell technology and encapsulation package as the modules in the array under test. If this is
not the case, the spectral mismatch shall be reported or an estimate of the uncertainty shall
be made as part of the analysis. Spectral mismatch is of particular concern with thin film
modules.
For modules that concentrate sunlight with an optical concentration ratio of greater than 3:1,
at least one radiometer shall provide a collimated measure of direct normal irradiance
(IEC 60904-4).
The temperature of the reference device shall be measured using instrumentation with an
accuracy of ±1 °C with repeatability of ±0,5 °C. If the reference device has internal correction
for temperature or if the reference device is a pyranometer with a temperature coefficient
< 0,02 %/°C, temperature measurement is not required. However, the mounting of a
thermopile shall be consistent with the conditions used for calibrating it.
A suitable means is required to check that the reference device and the modules are coplanar
within ±2° accuracy.
NOTE A digital level or other calibrated device can be used to confirm coplanar modules.
An additional pyranometer is required for checking the uniformity of the in-plane radiance.
This radiometer shall provide a stable output, but need not be calibrated since it is only used
for relative measurements.
If spectral corrections will be made, a spectroradiometer is required that is capable of
measuring the spectral irradiance of the sunlight in the range of the spectral response of the
test specimen and the reference device.
4.2 Module temperature measurements
The temperature of the module backsheets of the array under test shall be measured using
instrumentation with an accuracy of ±1 °C with repeatability of ±0,5 °C. It is recommended to
mechanically attach a flat thermal sensor with fine leads directly to the backsheet in the
middle of a module and at least 10 cm from any junction box, but opposite an active part of
the module. The attachment method should not change the temperature of the module, as
may be identified by infrared imaging from the front of the module. An optical thermometer
may be used only if the backsheet emissivity has been calibrated well enough that the optical
thermometer accuracy is within 1 °C. A handheld contact thermometer may be used only if it
has been verified that the accuracy is within 1 °C.
NOTE Most handheld thermometers conduct heat into the handle of the thermometer causing a temperature
reading that is less than the actual backsheet temperature.
4.3 Electrical measurements
A self-contained I-V curve tracing unit shall be able to accommodate the anticipated array
voltage, current, and power levels. The rate at which the unit sweeps the curve should be fast
enough to avoid changes in irradiance during the curve but slow enough to ensure that the PV
modules are achieving steady state conditions. Other equipment suitable for sweeping the
array through a significant portion of its I-V curve may be used though any limitations with
respect to the above requirements shall be clearly stated in the measurement report.
The I-V curve tracing unit shall be able to measure voltages and currents with an accuracy of
±1 % of the open-circuit voltage and short-circuit current using independent leads from the
terminals of the array under test and keeping all wires that would add series resistance as
short as possible. If only two leads are used, the error introduced shall be included in the

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SIST EN 61829:2016
IEC 61829:2015 © IEC 2015 – 9 –
uncertainty analysis. The measurement ranges of the data acquisition should be carefully
chosen to match the array being measured.
The instrumentation should be capable of measuring current at zero voltage, using a variable
bias (preferably electronic) to offset the voltage drop across the external series resistance. If
the instrumentation is not capable of reaching zero voltage bias, extrapolation may be used,
but the instrumentation shall be able to reach a voltage bias of 3 % of the device open-circuit
voltage.
5 Measurement procedure
5.1 Choose and record appropriate conditions for measurement
The ideal conditions for an outdoor I-V curve test are clear skies (no clouds and no fog) and
little wind. Variable irradiance and wind both introduce temperature transients in the array that
confound the accuracy of the measurements. In practice, time and contractual constraints
limit the periods in which it is possible to perform a test. Therefore, it is the responsibility of
the person(s) conducting the test to ensure that all tests are performed under the most stable
conditions possible, and that special attention is given to noting variable irradiance, wind, and
array temperatures. For example, even though irradiance during the course of the I-V
measurement does not vary more than 2 %, it may be that the irradiance increased by 30 % in
the 5 min leading up to the test, and that the array temperature may not have equilibrated
before the test was run.
Record the weather conditions, qualitatively, and periodically note when and how conditions
change over the period during which I-V curves are being taken. It is recommended to take a
picture of the sky and record the time periodically.
NOTE This information is for identifying potentially erroneous data, and is not directly used in the analysis.
5.2 Clean the modules
The cleanliness of the module surfaces shall be consistent with the intent of the test. The
state of cleanliness, whether or not cleaning has been attempted, shall be reported.
If the intent of the test is to detect any possible differences between fielded modules and
laboratory or factory measurements, either
a) the array shall be cleaned thoroughly immediately prior to the measurement, or
b) a representative string shall be tested immediately prior to and immediately after a
thorough cleaning. The level of soil on the array is determined by comparing the results of
the string I-V test before and after the cleaning. Such an assessment of soiling should be
conducted under very stable irradiance conditions, and care should be taken to allow the
string’s temperature to fully stabilize after the washing.
If the intent of the test is to document the performance of the array in a soiled state, then no
cleaning is expected, but the soiled state shall be documented through such things as
photographs and weather records defining the most recent rain.
5.3 Check for shading
Verify that there is no shading of the direct beam component of irradiance on the array under
test and that the environmental conditions meet the requirements of IEC 60904-1, with the
following exception: For measurements to be extrapolated to STC (Standard Test Conditions,
2
see Annex A), the total in-plane irradiance shall be at least 700 W/m and the incident sun
beam shall be within a cone of 45° full-aperture angle around the module normal.
There may be times when it is desirable to measure an I-V curve when the array is partially
shaded either by nearby objects or self-shading. This procedure may be used for the

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measurement procedure, but the correction of the shaded I-V curve to standard test
...