ABSTRACT When epoxy resin insulators and bushings in high‐voltage switchgears run in high humidity or significant temperature difference environments, condensation is easy to form on their surfaces, which may lead to a decrease in insulation performance and affect their long‐term operation. Room temperature vulcanized silicone rubber (RTV) coating has good anti‐pollution flashover performance and is widely used on the surface of ceramic or glass insulators to improve their electrical insulation performance. Based on this, RTV coating can be used to improve the electrical properties of epoxy resin in condensation environments, but it still faces the risk of aging failure under the coupling of electric field and humidity. In this paper, the RTV coating method is used to study the electrical characteristics of coatings with different thicknesses (0.3–0.6 mm) during charged aging. The charged aging characteristics of RTV coatings with different thicknesses in condensation environments were analyzed by testing the microstructure, infrared spectrum, dielectric loss and flashover voltage of the samples. The results show that the surface damage of the original sample is the most serious after aging, and a large number of cracks and holes are generated on the surface, while a small amount of particulate matter appears on the surface of the sample coated with RTV coating. With the increase of coating thickness, the static contact angle of the sample surface gradually increases, the aging rate of the RTV coating slows down, and the insulation performance is significantly improved. The electrical performance of the 0.6 mm coating sample is better than that of the thinner coating of 0.3 mm, showing higher surface resistivity and volume resistivity, and has strong resistance to charged aging in the flashover voltage and dielectric loss tests. This study can provide some reference for improving the insulation performance of switchgear in high humidity and condensation environments.
Du et al. (Wed,) studied this question.