A method for simulating powdering of silicone rubber composite insulator in coastal areas

Abstract

In recent years, the powdering phenomenon often has been found in suspension composite insulators operating in outdoor environments, and there is currently a gap in research on the composition and formation process of powdered substance. A method for simulating powdering of silicone rubber (SiR) in a high humidity salt-fog environment is proposed, and the obtained powder is compared with the natural powder. Test results show that the powder obtained from artificial environments is similar to the natural powder in coastal areas, which proves that this method is reasonable to simulate the powdering process. Powdered substances are generally composed of two types of substances, Type I is an inorganic filler and its dehydration product and Type II is a small molecular siloxane. The average particle size of artificial powder is 8–10 μm, while that of natural powder is 3–5 μm. All the dielectric properties of powdered SiR decreased, and after 12 h of ageing, the dielectric properties of the artificial sample were close to those in coastal areas, and the element composition was also similar. Aluminium hydroxide (Al(OH)₃) crystals were detected in both powders. The change trend of the characteristic functional groups in the infrared spectrum of the artificial powder is consistent with that of the natural powder, but the degree of molecular chain bond destruction is lower.