Cleaning effect of rainfall on salt in pollution layer of silicone rubber insulators

Electric properties of insulators are significantly affected by the amount of salt in pollution layer. In this paper, cleaning effect of rainfall on salt in pollution of silicone rubber insulators was studied under artificial rainfall. Factors including duration and intensity of rainfall, hydrophobicity of pollution layer as well as discharge on surface of pollution were studied with artificially and naturally polluted insulators. The obtained results indicate that: factors mentioned above all had significant impact on cleaning effect. Hydrophobicity and surface discharge could weaken cleaning effect of rainfall. With cleaning duration increasing, residual salt would fall down to a stable percent which was related to intensity of rainfall. A modified diffusion model based on Fick diffusion law could be used to characterize the salt´s cleaning process of naturally polluted silicone rubber insulators under rainfall.