IEC 62979-2017 PDF

Full title and description

Photovoltaic modules - Bypass diode - Thermal runaway test. This international standard specifies a test method to evaluate whether a bypass diode as mounted in a PV module is susceptible to thermal runaway or whether the module provides sufficient cooling for the diode to survive the transition from forward-bias to reverse-bias without overheating.

Abstract

IEC 62979:2017 defines a practical thermal-runaway test procedure for bypass diodes installed in photovoltaic modules. The method is particularly suited to Schottky barrier diodes, which can show increasing reverse leakage with temperature and therefore a higher risk of thermal runaway; the standard sets out test steps, pass/fail criteria and reporting requirements to determine diode safety in-module.

General information

• Status: Published / Valid
• Publication date: 10 August 2017
• Publisher: International Electrotechnical Commission (IEC)
• ICS / categories: 27.160 (Solar energy engineering)
• Edition / version: Edition 1.0 (2017)
• Number of pages: 13

Core bibliographic details above (edition, date, ICS, page count) follow the IEC publication record.

Scope

IEC 62979:2017 provides a method for evaluating whether a bypass diode, as mounted in the photovoltaic module, is susceptible to thermal runaway or whether there is sufficient cooling for it to survive the transition from forward-bias operation to reverse-bias operation without overheating. The scope explicitly notes applicability to Schottky barrier diodes because of their temperature-dependent reverse leakage behaviour and describes the intended test environment and outcome reporting.

Key topics and requirements

• Definition of the thermal runaway phenomenon for bypass diodes in PV modules.
• Test sequence to move a diode from forward-bias to reverse-bias while monitoring temperature and leakage current.
• Pass/fail criteria based on temperature rise, diode survival, and absence of destructive overheating.
• Requirements for test instrumentation, thermal measurement points and data recording.
• Test report content and required information (test conditions, specimen description, results and conclusions).
• Special considerations for Schottky barrier diodes and guidance on interpreting leakage-current behaviour under reverse bias at elevated temperature.

These topics mirror the standard’s table of contents and normative test/reporting requirements.

Typical use and users

This standard is used by photovoltaic module manufacturers (to verify module diode mounting and thermal performance), diode and component suppliers (to assess diode suitability for module use), independent test laboratories and certification bodies (for type testing and safety verification), design and reliability engineers, and R&D groups investigating module failure modes and thermal management.

Related standards

IEC 62979 is complementary to PV module design and safety standards such as IEC 61215 (design qualification) and IEC 61730 (safety requirements) and is published under the work of IEC TC 82. It has identical European adoption as EN 62979:2017 and is referenced by related PV terminology and guidance documents.

Keywords

photovoltaic modules; bypass diode; thermal runaway; Schottky barrier diode; thermal test; reverse leakage; PV safety; IEC TC 82; module qualification; test report.

FAQ

Q: What is this standard?

A: IEC 62979:2017 is an international standard that specifies a thermal-runaway test method for bypass diodes mounted in photovoltaic modules.

Q: What does it cover?

A: It covers the test procedure, instrumentation and measurement points, pass/fail criteria and the required test report to determine if a bypass diode will overheat (thermal runaway) when it transitions from forward to reverse bias while installed in a module.

Q: Who typically uses it?

A: PV module manufacturers, diode/component suppliers, test laboratories, certification bodies, and reliability and design engineers working on PV module safety and qualification.

Q: Is it current or superseded?

A: IEC 62979:2017 is the first edition published 10 August 2017 and is listed as a published/valid IEC standard; the IEC record indicates stability to 2026 for this edition.

Q: Is it part of a series?

A: It is a stand‑alone test standard within the suite of IEC TC 82 photovoltaic standards (complementary to standards such as IEC 61215 and IEC 61730) and has been adopted identically at the European level as EN 62979:2017.

Q: What are the key keywords?

A: Photovoltaic module, bypass diode, thermal runaway, Schottky diode, reverse leakage, thermal test, module qualification.