Experience with the detection of faulty composite insulators onhigh-voltage power lines by the electric field measurement method

摘要

Hydro-Quebec's experience with polymer insulators began in 1977. Ansixteen km section of a 735 kV transmission line near Quebec City wasnthen re-insulated with 282 composite insulators of three different makesnin equal proportions. The objective was to study them under real servicenconditions in order to evaluate their performance and to assess thenrelative merits of each make. This experimentation was later extended tonsome other lines and/or voltage levels and has continued up to now.nDuring all these years, various methods of testing composite insulatorsnin-service have been experimented with and early in the 1990s, the firstndevice developed at IREQ for the in-situ testing of porcelain insulatorsnby the electric field method was modified and adapted for use onncomposite suspension insulators. This paper presents a few cases ofninsulators having a particularly dangerous type of failure mode andnfound on the lines by the use of the electric field method. Somenbackground information on the detection of defects by this method isnalso given and some of the experiments done in the laboratory onncomposite insulators to define the limits of the method are described