Correlation of AC, switching surge and DC breakdown test results for insulating blankets and line hoses

Abstract

The paper presents the information reported during the ESMO-90 panel session, entitled "Rationale for Test Criteria,, o f Live-Line Maintenance Protective Equipment . The paper discusses the rationale for electrical testing of live line maintenance tools, in particular, the Insulating Protective Equipment, (IPE), like insulating blankets and line hoses. The present status of such testing is compared to the existing standards. The main thrust of the paper is the presentation of test results from a special international test program involving ten laboratories. Data are given on the breakdown voltage correlation between power frequency, direct current and switching overvoltage tests. The results indicate that the equivalence in testing between power frequency and DC, and power frequency and switching overvoltage now used in the industry and standards may be incorrect.Kevwords : Insulating Protective Equipment, electrical testing, live-line maintenance, safety.In cooperation between IEC-TC 78 and IEEE ESMOL Subcommittee, a special test program was set up to establish a correlation between power frequency, switch-