SIST EN 62788-1-2:2016

Measurement procedures for materials used in photovoltaic modules - Part 1-2: Encapsulants - Measurement of volume resistivity of photovoltaic encapsulation and backsheet materials

IEC 62788-1 2:2016 provides a method and guidelines for measuring the volume resistivity of materials used as encapsulation, edge seals, front-sheets, backsheets, or any other insulating material in a photovoltaic (PV) module. The test is performed on dry, humid or wet preconditioned samples. In the case of frontsheets and backsheets comprised of multiple layers, the measured resistivity is an effective value. This test is designed for room temperature measurement, but can also be utilized at higher temperatures.

Messverfahren für Werkstoffe, die in Photovoltaikmodulen verwendet werden - Teil 1-2: Verkapselungsstoffe - Messung des spezifischen Durchgangswiderstandes von Verkapselungsstoffen und anderen Polymer-Materialien von Photovoltaikmodulen

Procédures de mesure des matériaux utilisés dans les modules photovoltaïques - Partie 1-2: Encapsulants - Mesurage de la résistivité transversale des encapsulants photovoltaïques et autres matériaux polymères

L'IEC 62788-1-2:2016 fournit une méthode et des lignes directrices pour la mesure de la résistivité transversale des matériaux utilisés comme matériaux d'encapsulation, joints d'étanchéité périphériques, couches avant et couches arrière, ou tout autre matériau isolant dans un module photovoltaïque (PV). L'essai est effectué sur des échantillons préconditionnés secs, humides ou mouillés. Dans le cas des couches avant et des couches arrière qui comprennent plusieurs couches, la résistivité mesurée est une valeur efficace. Cet essai est conçu pour un mesurage à la température ambiante, mais il peut également être utilisé à des températures plus élevées.

Merilni postopki za materiale, uporabljene v fotonapetostnih modulih - 1-2. del: Enkapsulanti - Merjenje prostorninske upornosti fotonapetostnih enkapsulacij in materialov nosilne plasti

Ta del standarda IEC 62788 določa metodo in smernice za merjenje prostorninske upornosti materialov, ki se uporabljajo kot enkapsulacije, robna tesnila, prednje plasti, nosilne plasti ali kateri koli drug izolacijski material v fotonapetostnem (PV) modulu. Preskus se opravi za suhe, vlažne ali mokre predhodno pripravljene vzorce. V primeru večslojnih prednjih plasti in nosilnih plasti je izmerjena upornost dejanska vrednost. Ta preskus je namenjen za merjenje pri sobni temperaturi, mogoče pa ga je uporabiti tudi pri višjih temperaturah.
Znano je, da pride do razpadanja fotonapetostnih modulov delno zaradi elektromehanske korozije in drugih potencialnih induciranih procesov razpadanja. Ti procesi so lahko odvisni od upornosti polimernega sestavnega dela. Zaradi tega je DC-upornost polimernih delov pomembna za zasnovo modula in trajnost na področju uporabe. Upornost je lahko odvisna od stanja obdelave, temperature, vsebnosti vode in zgodovine napetostnih pogojev. Vključenih je več možnosti, ki omogočajo izvedbo meritve na način, skladen z reprezentativnimi pogoji modulov na področju uporabe.
Večina metod in opreme za merjenje upornosti običajno postane nenatančna in spremenljiva za materiale s prostorninsko upornostjo nad 1016 Ω cm [5]1. Zaradi tega se ta standard uporablja za meritve vrednosti, nižjih od 1⋅1017 Ω cm.
Za meritev so primerni tako monolitni kot večslojni materiali (npr. prednje plasti in nosilne plasti). Metode so opisane za merjenje pri sobni temperaturi, vključene pa so tudi smernice za preskušanje pri višjih temperaturah.
Rezultati se lahko razlikujejo glede na vsebnost vlage, zaradi česar naj bi materiale preskušali na način, pričakovan za uporabo. Vključeni so postopki predhodne obdelave za suho, vlažno in mokro okolje.
Odvisno od materiala bo na izmerjeni rezultat vplivala zgodovina napetostnih pogojev. Stopnja spremembe toka in čas do ravnovesja je odvisna od materiala, pri čemer vzpostavitev statične ravni pogostokrat traja več ur ali dni. Zaradi tega sta vključeni dolgoročna in kratkoročna metoda (A in B). Podana kratkoročna metoda B z izmenično polarnostjo je namenjena za kvalitativno primerjavo. Dolgoročna metoda A z vklopom/izklopom polarnosti se priporoča za karakterizacijo v povezavi z upornostjo PID.
Meritve, pridobljene z eno od teh metod, lahko proizvajalci materiala uporabijo za nadzor kakovosti svojih elektroizolacijskih materialov in navedbe v tehničnih listih proizvodov. Proizvajalci fotonapetostnih modulov lahko ti metodi uporabijo za namene sprejemljivosti materiala, izbire materiala, razvoj procesov, analizo zasnove ali analizo napak.
To merilno metodo je mogoče uporabiti tudi za nadzor učinkovitosti delovanja elektroizolacijskih materialov po izpostavljenosti vremenskim vplivom, na podlagi česar se poda ocena trajnosti.

General Information

• Status: Published
• Publication Date: 28-Aug-2016
• ICS: 27.160 - Solar energy engineering
• Technical Committee: PVS - Solar photovoltaic energy systems
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 08-Jul-2016
• Due Date: 12-Sep-2016
• Completion Date: 29-Aug-2016
• Ref Project: EN 62788-1-2:2016 - Measurement procedures for materials used in photovoltaic modules - Part 1-2: Encapsulants - Measurement of volume resistivity of photovoltaic encapsulants and other polymeric materials

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 62788-1-2:2016
01-september-2016
Merilni postopki za materiale, uporabljene v fotonapetostnih modulih - 1-2. del:
Enkapsulanti - Merjenje prostorninske upornosti fotonapetostnih enkapsulacij in
materialov nosilne plasti
Measurement procedures for materials used in photovoltaic modules - Part 1-2:
Encapsulants - Measurement of volume resistivity of photovoltaic encapsulation and
backsheet materials
Ta slovenski standard je istoveten z: EN 62788-1-2:2016
ICS:
27.160 6RQþQDHQHUJLMD Solar energy engineering
SIST EN 62788-1-2:2016 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 62788-1-2:2016

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SIST EN 62788-1-2:2016


EUROPEAN STANDARD EN 62788-1-2

NORME EUROPÉENNE

EUROPÄISCHE NORM
June 2016
ICS 27.160

English Version
Measurement procedures for materials used in photovoltaic
modules - Part 1-2: Encapsulants - Measurement of volume
resistivity of photovoltaic encapsulants and other polymeric
materials
(IEC 62788-1-2:2016)
Procédures de mesure des matériaux utilisés dans les Messverfahren für Werkstoffe, die in Photovoltaikmodulen
modules photovoltaïques - Partie 1-2: Encapsulants - verwendet werden - Teil 1-2: Verkapselungsstoffe -
Mesurage de la résistivité transversale des encapsulants Messung des spezifischen Durchgangswiderstandes von
photovoltaïques et autres matériaux polymères Verkapselungsstoffen und Rückseitenfolien von
(IEC 62788-1-2:2016) Photovoltaikmodulen
(IEC 62788-1-2:2016)
This European Standard was approved by CENELEC on 2016-06-16. 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 62788-1-2:2016 E

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SIST EN 62788-1-2:2016
EN 62788-1-2:2016
European foreword
The text of document 82/1085/FDIS, future edition 1 of IEC 62788-1-2, prepared by IEC/TC 82 “Solar
photovoltaic energy systems" was submitted to the IEC-CENELEC parallel vote and approved by
CENELEC as EN 62788-1-2:2016.

The following dates are fixed:
(dop) 2017-03-16
• 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) 2019-06-16
standards conflicting with the
document have to be withdrawn


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 62788-1-2:2016 was approved by CENELEC as a
European Standard without any modification.
2

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SIST EN 62788-1-2:2016
EN 62788-1-2:2016

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 61340-2-3 2000 Electrostatics -- Part 2-3: Methods of test EN 61340-2-3 2000
for determining the resistance and
resistivity of solid planar materials used to
avoid electrostatic charge accumulation
IEC 62631-3-2 2015 Dielectric and resistive properties of solid EN 62631-3-2 2016
insulating materials - Part 3-2
Determination of resistive properties (DC
Methods) - Surface resistance and surface
resistivity
ISO/IEC 17025 -  General requirements for the competence - -
of testing and calibration laboratories
ASTM D 257-14 -  Standard Test Methods for DC Resistance - -
or Conductance of Insulating Materials

3

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SIST EN 62788-1-2:2016

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SIST EN 62788-1-2:2016



IEC 62788-1-2

®


Edition 1.0 2016-05




INTERNATIONAL



STANDARD




NORME



INTERNATIONALE











Measurement procedures for materials used in photovoltaic modules –

Part 1-2: Encapsulants – Measurement of volume resistivity of photovoltaic

encapsulants and other polymeric materials




Procédures de mesure des matériaux utilisés dans les modules

photovoltaïques –


Partie 1-2: Encapsulants – Mesurage de la résistivité transversale des

encapsulants photovoltaïques et autres matériaux polymères












INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE


INTERNATIONALE




ICS 27.160 ISBN 978-2-8322-3349-8



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 62788-1-2:2016
– 2 – IEC 62788-1-2:2016  IEC 2016
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references. 6
3 Sampling . 6
4 Apparatus . 6
5 Procedure . 7
5.1 Preconditioning . 7
5.2 Test conditions . 8
5.2.1 Room temperature . 8
5.2.2 Elevated temperatures . 8
5.3 Measurement voltage . 8
5.3.1 Method A voltage . 8
5.3.2 Method B voltage . 9
5.4 Measurement cycle . 9
5.4.1 Method A cycle . 9
5.4.2 Method B cycle . 9
5.5 Results . 9
6 Test report. 10
Annex A (informative) Historical studies of the volume resistivity of encapsulation
materials . 12
Annex B (informative) Example data . 13
Bibliography . 14

Figure 1 – Schematic of electrode apparatus for resistivity measurements . 7
Figure B.1 – Example data showing current and voltage as a function of time for
Method A measurement . 13

Table B.1 – End of cycle current measurements and values used for calculation of
volume resistivity according to Method A . 13

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SIST EN 62788-1-2:2016
IEC 62788-1-2:2016  IEC 2016 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

MEASUREMENT PROCEDURES FOR MATERIALS
USED IN PHOTOVOLTAIC MODULES –

Part 1-2: Encapsulants –
Measurement of volume resistivity of
photovoltaic encapsulants and other polymeric materials

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 62788-1-2 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
82/1085/FDIS 82/1105/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.

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SIST EN 62788-1-2:2016
– 4 – IEC 62788-1-2:2016  IEC 2016
A list of all parts in the IEC 62788 series, published under the general title Measurement
procedures for materials used in photovoltaic modules, can be found on the IEC website.
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 62788-1-2:2016
IEC 62788-1-2:2016  IEC 2016 – 5 –
MEASUREMENT PROCEDURES FOR MATERIALS
USED IN PHOTOVOLTAIC MODULES –

Part 1-2: Encapsulants –
Measurement of volume resistivity of
photovoltaic encapsulants and other polymeric materials



1 Scope
This part of IEC 62788 provides a method and guidelines for measuring the volume resistivity
of materials used as encapsulation, edge seals, front-sheets, backsheets, or any other
insulating material in a photovoltaic (PV) module. The test is performed on dry, humid or wet
preconditioned samples. In the case of frontsheets and backsheets comprised of multiple
layers, the measured resistivity is an effective value. This test is designed for room
temperature measurement, but can also be utilized at higher temperatures.
Degradation of PV modules is known to occur in part by electrochemical corrosion, and other
potential induced degradation processes. These processes may be dependent upon the
resistivity of a polymeric component. Therefore, the DC resistivity of polymeric components is
relevant to module design and durability in the field. The resistivity may depend on cure state,
temperature, water content, and voltage history. A number of options are included to allow the
measurement to be performed in a manner consistent with representative fielded module
conditions.
Most resistivity measurement methods and equipment typically become inaccurate and
16
1
Ω∙cm [5] .Therefore, this standard is
variable for materials with volume resistivity above 10
17
used for measurements less than 1⋅10 Ω∙cm.
Both monolithic and multilayer materials (e.g. frontsheets and backsheets) are suitable for
measurement. Methods are described for room temperature measurement, with guidelines
included for testing at elevated temperatures.
Results will vary with moisture content, therefore materials should be tested in a manner
anticipatory of usage. Preconditioning procedures for dry, humid and wet environments are
included.
Depending on the material, voltage history will affect the measured result. The rate of change
of current, and time to equilibrium varies with material often taking hours or days to come to a
static level. For this reason, long and short duration methods are included (Methods A and B).
The specified short-duration alternating polarity Method B is intended for qualitative
comparison. Method A, long-duration on/off polarity, is recommended for characterization with
regard to PID resistance.
Measurements obtained using either method may be used by material manufacturers for the
purpose of quality control of their electrical insulating material as well as for reporting in
product datasheets. PV module manufacturers may use these methods for the purpose of
material acceptance, material selection, process development, design analysis, or failure
analysis.
_______________
1
 Numbers in square brackets refer to the Bibliography.

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SIST EN 62788-1-2:2016
– 6 – IEC 62788-1-2:2016  IEC 2016
This measurement method can also be utilized to monitor the performance of electrical
insulating materials after weathering, to assess their durability.
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 61340-2-3:2000, Electrostatics – Part 2-3: Methods for test for determining the resistance
and resistivity of solid planar materials used to avoid electrostatic charge accumulation
IEC 62631-3-2:2015, Dielectric and resistive properties of solid insulating materials – Part 3-
2: Determination of resistive properties (DC methods) – Surface resistance and surfa
...