Wetting characteristics of various kinds of insulators

Recently, superior anti-contamination insulators based on the wetting characteristics, such as, polymer and room temperature vulcanized silicone rubber coated insulators having superior hydrophobicity, and semiconducting glaze insulators having drying effect by leakage current in the glaze, have been developed. However, such superior performances of these insulators can not be always expected. Hydrophobicity of silicone rubber and drying effect of semiconducting glaze may not be fully effective under some wetting conditions. In order to establish application and maintenance guidelines for these insulators, we investigated the netting characteristics of these new insulators comparing with standard porcelain insulators both in artificial fog chamber and in outdoor field. We could confirm the effects of relative humidity on the deliquescence/absorption of water vapor in air by salt deposited on actual insulator surface.