Effects of moss on electrical performance of electrical equipment

In this paper, moss distribution on the surface of insulators with and without room temperature vulcanized silicone rubber (RTV) coating was investigated. The flashover voltages of glass insulators, RTV coated glass insulators, mossy glass insulators and mossy RTV coated glass insulators were measured. In addition, the electric field strength is simulated for insulators with moss contamination. The results show that for insulators without RTV coating, the moss was mainly concentrated on the upper surface of the insulator near the pillar, while the moss on the surface of insulators with RTV coating was mainly concentrated near the umbrella skirt of the insulator. The adhesion of moss does not have a particularly significant effect on the dry flashover voltage of insulators. However, under high humidity conditions, the moss absorbs moisture from the air and deposits dirt from the atmosphere, which increases the electrical conductivity of the surface and causes a steep drop in electric field strength at the junction of the coating and the mossy area on the insulator surface. Therefore, the wet flashover voltage and foul flashover voltage of the mossy glass insulator and the RTV coated insulator were lower than those of the sample without moss on the surface.