Surface Roughness Effect on the Hydrophobicity Characteristic of Operating Composite Insulators

Abstract

Pretreatment needs to be done before measuring the hydrophobicity of the composite insulators. However, the necessity of such pretreatment is questionable for operating composite insulators. Therefore, surface roughness of light pollution level, heavily pollution level, chalking and the impact of surface roughness on hydrophobicity characteristic (HC) was investigated in this paper. The paper does the research on the result indicated the surface roughness is one of main factor about the pretreatment effect on HC level and static contact angle. The pretreatment effect on HC level and static contact angle seemed to be very obvious and the percentage of static contact angle changed up to 15.3%, as the surface roughness was varied. The R-a and R-SM of different pollution level shed percentage change up to 130% and 269%. While R-a and R-SM of high surface roughness degree reach up to 3.242 mu m and 400 mu m, the hydrophobicity on the composite insulators lost permanent. The surface roughness can lead the water drop to two kinds of states transitions and it can make sample static contact Angle changed up to 31% within 10 minutes, which will also cause the different results of two measurement methods. Surface roughness of composite insulators was suggested as the added parameter in hydrophobicity tests.