1998 Volume 118 Issue 5 Pages 502-508
Acid rain is one of the more serious environmental contaminations. Some research results have shown the influence of acid rain on the tracking resistance of outdoor polymer insulating materials. The degradation effects of acid rain on the outdoor composite insulators of silicone rubber and Ethylene Vinyl Acetate (EVA) are investigated by the accelerating aging of artificial acid rain in this paper. Based on the investigation of acid rain, the artificial acid rain is chosen to agree well with the actual ingredients of precipitation. Furthermore, the influence of hydrophobicity degradation on the surface discharge current of insulators is studied. The relations among the hydrophobicity degradation, micro chemical structure and physical morphology of material surface layer are discussed. Test results show that the insulators suffer a large attack and degradation from acid rain. The surface becomes rough, hydrophobicity decreases and surface discharge currentincreases. The erosion of acid rain on the insulating materials in power system is larger than that on the outdoor materialsfor the other purposes. Silicone rubber shows a larger resistance against acid rain than EVA.