IEC TR 60727-2-1993 PDF

Full title and description

IEC/TS 60727-2:1993 — Evaluation of electrical endurance of electrical insulation systems — Part 2: Evaluation procedures based on extreme‑value distributions. This Technical Specification provides statistical procedures and worked examples for analysing electrical‑endurance test data whose distributions are not adequately described by a normal (Gaussian) model, with emphasis on time‑to‑breakdown at constant voltage or breakdown voltage under long‑term increasing voltage stress.

Abstract

Part 2 of IEC 60727 gives guidance on statistical evaluation methods for electrical endurance tests when observed lifetimes or breakdown voltages follow extreme‑value type behaviour rather than a normal distribution. It explains appropriate distribution selection, parameter estimation and reporting practices, and includes numerical examples for groups of specimens and model insulation systems. The document assumes electrical stress is the dominant ageing factor and complements Part 1 (procedures for normal distributions).

General information

• Status: Withdrawn (withdrawal recorded by IEC in 2007).
• Publication date: 26 February 1993 (Edition 1.0).
• Publisher: International Electrotechnical Commission (IEC), TC 112.
• ICS / categories: 29.080.30 (Electrical insulating materials and systems).
• Edition / version: Edition 1.0 (Technical Specification / Technical Report status).
• Number of pages: 71 pages.

Scope

The Technical Specification covers statistical procedures to analyse data from electrical‑endurance testing of insulation systems — specifically time‑to‑breakdown under constant voltage stress and breakdown voltage under long‑term ramped stress — for groups of specimens or representative models. It addresses cases where extreme‑value distributions better represent the data than a normal distribution, gives guidance on selection of models and estimators, and provides numerical examples and reporting recommendations. The specification is intended to be used where electrical stress is the primary ageing factor.

Key topics and requirements

• Statistical treatment of electrical endurance data when distributions are of extreme‑value type (non‑Gaussian).
• Guidance on selection of appropriate extreme‑value models and parameter estimation techniques for time‑to‑failure and breakdown‑voltage data.
• Procedures for analysing grouped specimen results and for extrapolating to intended lifetimes or voltages.
• Numerical examples illustrating methods and reporting formats for test evaluation.
• Assumption that electrical stress predominates among ageing factors and implication for test design and interpretation.

Typical use and users

Used by test engineers, reliability statisticians, materials and insulation manufacturers, independent test laboratories, and standards committees when evaluating electrical‑endurance test results that do not follow normal distributions. It is useful for interpreting time‑to‑breakdown data, setting qualification criteria, and preparing technical test reports.

Related standards

Closely related to IEC/TS 60727‑1 (Part 1: procedures based on normal distributions). Other later IEC publications on electrical‑endurance evaluation and insulation assessment (for example IEC publications addressing general methods for electrical endurance) and national/adopted equivalents may provide current guidance. The IEC TS has also been adopted or referenced in some national standards (e.g., Chinese adoption IDT GB/T 23756.2‑2010 corresponds to IEC/TR 60727‑2:1993).

Keywords

electrical endurance; electrical insulation systems; time‑to‑breakdown; breakdown voltage; extreme‑value distributions; statistical evaluation; reliability; ageing; IEC TC 112.

FAQ

Q: What is this standard?

A: IEC/TS 60727‑2:1993 is a Technical Specification from the IEC that gives statistical evaluation procedures for electrical‑endurance tests of insulation systems when data follow extreme‑value type distributions.

Q: What does it cover?

A: It covers methods for analysing time‑to‑breakdown (constant voltage) and breakdown‑voltage (long‑term increasing voltage) data using extreme‑value distributions, including guidance on model selection, parameter estimation, data presentation and numerical examples.

Q: Who typically uses it?

A: Test laboratories, reliability and materials engineers, insulation manufacturers, and standards/technical committees concerned with electrical insulation endurance and qualification use this document as a statistical reference for non‑Gaussian test data.

Q: Is it current or superseded?

A: IEC/TS 60727‑2:1993 has been withdrawn (IEC records show a withdrawal date in 2007). Users should consult later IEC publications and relevant national/adopted standards for current practice; some aspects may have been incorporated into other IEC work or national equivalents.

Q: Is it part of a series?

A: Yes — it is Part 2 of IEC 60727. Part 1 (IEC/TS 60727‑1) provides complementary guidance for cases where normal (Gaussian) distributions apply.

Q: What are the key keywords?

A: Electrical endurance, electrical insulation systems, extreme‑value distributions, time‑to‑breakdown, breakdown voltage, statistical evaluation, reliability.