Experiences on ageing of epoxy overhead insulators

摘要

A series of various medium voltagernoverhead insulator constructions has been designedrnand executed. These being considered as test modelsrnand prototype insulators, have been subjected tornlaboratory tests and partly to field service tests underrnsea climate conditions. The main aim was to evaluaternthe applicability of the materials and design solutionsrnused. As main criteria of casting epoxy resinsrnapplicability for outdoor conditions, the followingrnhave been adopted:rn- resistance to electrical arc,rn- resistance to tracking,rn- stability of the above parameters at longrnlasting,rnThe comparison tests on the resistance to tracking ofrnvarious epoxy compositions have been carried out basingrnupon high voltage methods. The test resultsrnenabled to select some compositions for long lastingrninvestigations in which the differential methodrn(ASTM D 2302) has been assumed as mostrnpracticable for estimation of creepage currentrnresistance changes due to ultra-violet radiationrnestimation.