Distribution of natural pollution surface layers on silicone rubber insulators and their UV absorption

The authors present results of uniformity distribution studies of an industrial type pollution layer on RTV silicone rubber insulator surfaces under natural conditions. Similar distributions were also measured on porcelain insulators. Results of investigations of the layer ability to absorb the UV irradiation for different types of contaminants, i.e. artificial and natural ones, are presented. It was found that naturally polluted composite insulators did not lose their good insulating properties after a long time in an extremely polluted area. Specifically, it was found that seven years service experience with silicone composite insulators have proved their usefulness for work under heavily polluted conditions. The housing material lost neither its elasticity nor its hydrophobic properties, despite the pollution layer accumulation on its surface. The layer is more uniformly distributed and thinner than on porcelain insulators. It can absorb about 40 to 60% of natural UV irradiation and significantly reduces its destructive action on the housing material. It is suggested that the good behaviour under these conditions may be caused by a screening effect of the surface pollutant, because of its significant ability to absorb UV irradiation