1、BSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06Photovoltaic modules - Bypass diode - Thermal runaway test (IEC 2979:2017)BS EN 62979:2017EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 62979 October 2017 ICS 27.160 English Version Photovoltaic module - Bypass d
2、iode - Thermal runaway test (IEC 62979:2017) Essai demballement thermique portant sur les diodes de drivation des modules photovoltaques (IEC 62979:2017) Photvoltaik-Module - Bypass-Diode - Prfung des thermischen Durchgehens (IEC 62979:2017) This European Standard was approved by CENELEC on 2017-09-
3、14. 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 obtai
4、ned 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
5、 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,
6、 Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. European Committee for Electrotechnical Standardization Comit Europen de Normalisation E
7、lectrotechnique Europisches Komitee fr Elektrotechnische Normung CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2017 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members. Ref. No. EN 62979:2017 E National forewordThis British Standa
8、rd is the UK implementation of EN 62979:2017. It is identical to IEC 62979:2017.The UK participation in its preparation was entrusted to Technical Committee GEL/82, Photovoltaic Energy Systems.A list of organizations represented on this committee can be obtained on request to its secretary.This publ
9、ication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2017 Published by BSI Standards Limited 2017ISBN 978 0 580 91892 6ICS 27.160Compliance with a British Standard cannot confer immunity f
10、rom legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 December 2017.Amendments/corrigenda issued since publicationDate Text affected BRITISH STANDARDBS EN 62979:2017EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 62979
11、 October 2017 ICS 27.160 English Version Photovoltaic module - Bypass diode - Thermal runaway test (IEC 62979:2017) Essai demballement thermique portant sur les diodes de drivation des modules photovoltaques (IEC 62979:2017) Photvoltaik-Module - Bypass-Diode - Prfung des thermischen Durchgehens (IEC
12、 62979:2017) This European Standard was approved by CENELEC on 2017-09-14. 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 bib
13、liographical 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 r
14、esponsibility 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, F
15、inland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. European Committe
16、e for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2017 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC
17、 Members. Ref. No. EN 62979:2017 E BS EN 62979:2017EN 62979:2017 2 European foreword The text of document 82/1269/FDIS, future edition 1 of IEC 62979, prepared by IEC/TC 82 “Solar photovoltaic energy systems“ was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as EN 62979:2017. Th
18、e following dates are fixed: latest date by which the document has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2018-06-14 latest date by which the national standards conflicting with the document have to be withdrawn (dow) 2020-09-14 A
19、ttention 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. Endorsement notice The text of the International Standard IEC 62979:2017 was approved by CENELEC a
20、s a European Standard without any modification. BS EN 62979:2017EN 62979:2017 3 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 c
21、onstitutes 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 When an International Publication has been modified by common modifications, indicated by (
22、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/TS 61836 - Solar photovoltaic energy systems - Terms, definitions and symbols - - BS EN 62979
23、2017This page deliberately left blank 2 IEC 62979:2017 IEC 2017 CONTENTS FOREWORD . 3 INTRODUCTION . 5 1 Scope 6 2 Normative references 6 3 Terms and definitions 6 4 Thermal runaway test 7 4.1 Diode thermal runaway . 7 4.2 Test conditions . 8 4.3 Preparation of test specimen. 8 4.4 Test equipment .
24、 9 4.5 Test procedure 10 5 Pass or fail criteria. 12 6 Test report . 12 Figure 1 Illustration of how thermal runaway occurs . 7 Figure 2 Circuit for measurement of Tleadand forward voltage 9 Figure 3 Circuit for flowing a forward current to the bypass diode 10 Figure 4 Circuit for applying a reverse
25、 bias voltage to the bypass diode. 10 Figure 5 The typical pattern of thermal runaway . 11 Figure 6 The pattern of non-thermal runaway . 11 2 IEC 62979:2017 IEC 2017 CONTENTS FOREWORD . 3 INTRODUCTION . 5 1 Scope 6 2 Normative references 6 3 Terms and definitions 6 4 Thermal runaway test 7 4.1 Diode
26、 thermal runaway . 7 4.2 Test conditions . 8 4.3 Preparation of test specimen. 8 4.4 Test equipment . 9 4.5 Test procedure 10 5 Pass or fail criteria. 12 6 Test report . 12 Figure 1 Illustration of how thermal runaway occurs . 7 Figure 2 Circuit for measurement of Tleadand forward voltage 9 Figure 3
27、 Circuit for flowing a forward current to the bypass diode 10 Figure 4 Circuit for applying a reverse bias voltage to the bypass diode. 10 Figure 5 The typical pattern of thermal runaway . 11 Figure 6 The pattern of non-thermal runaway . 11 BS EN 62979:2017IEC 62979:2017 IEC 2017 3 INTERNATIONAL ELE
28、CTROTECHNICAL COMMISSION _ PHOTOVOLTAIC MODULES BYPASS DIODE THERMAL RUNAWAY TEST 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 pro
29、mote 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
30、 (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 als
31、o 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 possi
32、ble, 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. Whi
33、le 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
34、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 attestati
35、on 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 th
36、is 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 in
37、direct, 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
38、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 62979 has been prep
39、ared by IEC technical committee 82: Solar photovoltaic energy systems. The text of this International Standard is based on the following documents: FDIS Report on voting 82/1269/FDIS 82/1311/RVD Full information on the voting for the approval of this International Standard can be found in the report
40、 on voting indicated in the above table. This document has been drafted in accordance with the ISO/IEC Directives, Part 2. BS EN 62979:2017 4 IEC 62979:2017 IEC 2017 The committee has decided that the contents of this document will remain unchanged until the stability date indicated on the IEC websi
41、te under “http:/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. A bilingual version of this publication may be issued at a later date. BS EN 62979:2017IEC 62979:2017 IEC 2017 5 INTROD
42、UCTION During the normal operation of PV modules the bypass diodes are reverse biased. When the PV module is partially shaded (for example by utility poles, buildings, or leaves), some of the cells in the PV module may not be able to produce the current being produced by the other cells in the serie
43、s string. The shaded cells are then driven into reverse bias so the bypass diode of the shaded cell-string becomes forward bias protecting the shaded cells. Under these circumstances, the temperature of the bypass diode increases due to the forward current flowing through the diode. It is in this co
44、ndition that the diodes are tested in accordance with IEC 61215-2:2016, 4.18.1: Bypass diode thermal test. When the shade is removed, operating conditions return to normal and the bypass diode is again reversed biased. Some of the diodes utilized as bypass diodes in PV modules have characteristics w
45、here the reverse bias leakage current increases with the diode temperature. So if the diode is already at an elevated temperature when reverse biased, there will be a substantial leakage current and the diode junction temperature can increase considerably. The worst case occurs when this heating exc
46、eeds the cooling capability of the junction box in which the diode is installed. As a result of this increasing temperature and leakage current, the diode can break down. These phenomena are called “thermal runaway”. The thermal design of the bypass diode in the junction box shall be verified to ens
47、ure that thermal runaway does not occur. BS EN 62979:2017 6 IEC 62979:2017 IEC 2017 PHOTOVOLTAIC MODULES BYPASS DIODE THERMAL RUNAWAY TEST 1 Scope This document provides a method for evaluating whether a bypass diode as mounted in the module is susceptible to thermal runaway or if there is sufficien
48、t cooling for it to survive the transition from forward bias operation to reverse bias operation without overheating. This test methodology is particularly suited for testing of Schottky barrier diodes, which have the characteristic of increasing leakage current as a function of reverse bias voltage
49、 at high temperature, making them more susceptible to thermal runaway. The test specimens which employ P/N diodes as bypass diodes are exempted from the thermal runaway test required herein, because the capability of P/N diodes to withstand the reverse bias is sufficiently high. 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 e
