Composite insulators are gaining ground-25 years of Swiss experience

This paper presents the newest applications of silicone composite insulators which are finding increasing use not only in Switzerland, but also in the power industry worldwide. These applications include interesting designs for railway overhead lines, medium voltage lines, and 400 kV high voltage overhead transmission lines. Solutions are presented for high-voltage outdoor equipment, which have been conceived and manufactured with housings made of silicone hollow core composite insulators and 400 kV compact lines. As far as is known, the first composite insulators manufactured in Switzerland around 1970 were hollow core insulators with a silicone weathershed and were used as housings for cable terminations. A short time later these were followed by solid core composite insulators, which were used as line post insulators in the newly-developed catenary support structures in the Latschberg railway tunnel. Further applications soon appeared, e.g., long-rod composite insulators for overhead interphase spacers, primarily on medium voltage lines. Hollow core insulators for current and voltage transformers as well as for bushings and test capacitors were also realized in this period. Today, there is an innovative, upcoming and internationally successful industry in Switzerland, making considerable investments in order to be able to play a major role in the expanding composite insulator business worldwide.