With the accelerating construction of strong smart grid

and the grid voltage level rising

performance requirements for the electrical insulation of electrical equipment also continue to increase.In terms of the advantages of RTV on antifouling

the ability of RTV-based paints coated insulator against pollution conditions can significantly increase

mainly due to RTV coating with hydrophobicity and migration.But when the hydrophobic surface is in the fully wet

many small drops of water on the surface will be gathered into to form large drops of water

which will distort the surface electric field.The flashover voltage of the hydrophobic surface’s separated water droplets under DC and AC electric field are analyzed comparatively in this paper

while some influencing factors such as different dielectrics and volume of water drops

are introduced in specific experiments

and their effects on the flashover voltage are analyzed.The flashover voltages are studied for hydrophobic and hydrophilic surface under DC field in order to find the differences of flashover voltage in both cases.