サーマルサイクリングで劣化された25KV用ポリマーガイシの雷インパルスによるダスト図形の解析

Abstract

Composite insulators used on HV transmission lines are made of a resin-impregnated fiberglass core covered by polymeric weathersheds. The first generation of polymer transmission line insulators significant advantages, compared with ceramic insulators, were; (a) Light weight-lower construction and transportation costs, (b) Vandalism resistanceless gunshot damage, and (c) High strength to weight ratio-longer spans/new tower designs so on. These advantages are especially attractive for extra high voltage transmission lines. The early experience was disappointing. Typical problems encountered after a few years of operation were; (A) Tracking and erosion of the shed material, (B) Chalking and crazing of the insulator surface, (C) Reduction of contamination flashover strength, and (D) Deterioration of mechanical strength so on. This paper discusses the change in electrical properties of 25KV insulator that have been subjected to thermal cycling. The electrical properties are investigated using the dust figure method and 50% flashover test.