Effect of surface roughness on flashover characteristics of silicone rubber.

To study how the flashover voltage of silicone rubber depends on surface roughness, we prepared samples of silicone rubber of varying surface roughness to explore the relationship between surface roughness and the hydrophobicity of silicone rubber. We investigate the surface-flashover voltage of these samples. The results show that an increase in surface roughness leads to a decrease in the hydrophobicity of silicone rubber. The-dry flashover voltage of a sample with high surface roughness increases with surface roughness, and the wet-flashover voltage is reversed. The flashover characteristics for a attached water droplet depend mainly on the length of the water droplet. • The relationship between surface roughness and the hydrophobicity of silicone rubber was explained. The test results show that the hydrophobicity of silicone rubber decreases with increasing surface roughness. The spray-grading method and the contact-angle method produce different results for the degree of hydrophobicity. • The relationship between the flashover voltage and the hydrophobicity of silicone rubber was explained. The wet-flashover voltage decreases with the increase of roughness. Numerical simulations show that the degree of distortion of the surface electric field increases with surface roughness. • By comparing simulation results with experimental results, it is considered that the dry-flashover characteristics of rough silicone rubber surface in air are determined by the creeping distance of the surface and the degree of electric field distortion. [ABSTRACT FROM AUTHOR]