Study On Aging Performance Of AC Composite Insulators

Composite insulators have been being widely used in power system due to the characteristics of high strength, light in weight, high comtamination flashover voltage, and convenient maintenance. Composite insulators have been being exposed to several factors action such as electrical, mechanical and environment. The aging problem of composite insulators aroused high focus by manufacturer, power company and research institute.AC composite insulators were systematically tested according to appearance, salt density, dust density, contamination analysis, hydrophobicity, comtamination flashover voltage, mechanics and electrical property of sheds, infra-red spectrum and thermally stablization. Typical aging characteristics of composite insulators in Guangdong province and northeast of China was concluded, the aging level method of composite insulator shed was determined. The aging quantitative analysis method of silicone rubber based on infrared spectrum absorption peak area was put forward, the relationship of various performance parameter and numerical range of shed were obtained, the relationship of shed property and severice environment with operating time, different position of shed was concluded, and such parameter of composite insulator including appearance, clear surface hydrophobicity, transference of hydrophobicity, tensile strength, hardness and dielectric strength was put forward to evaluate the aging performance of composite insulators sheds.The transference of hydrophobicity affected by salt density, dust density, six kinds of contamination components, temperature, humidity and ultraviolet irradiation was studied deeply. The change regular of transference of hydrophobicity and the value scope of contact angle of silicone rubber was obtained. The contact angle measurement influenced by water volume and roughness was analyzed, and the effect of electrical and mechanical property of silicone rubber after sanding was discovered.Eight group needle-plane corona discharge test equipment was designed, track wheel test system based on structure of grooved pulley was developed. Systematic acceleration ageing research on composite insulators including ultraviolet irradiation, moist heat, corona discharge, salt fog as well as track wheel test were carried out in order to quantify the hydrophobicity property, mechanical performance, appearance profile and dielectric characteristics and infra-red spectrum. According to the ageing tests data, effects of each ageing factor are verified. The ageing data regular of composite insulator and shed parameter scope at different stage were obtained. The aging mechanics of ultraviolet irradiation, moist heat, corona discharge, salt fog and track wheel test was explained. The test result was used for realization of relationship of composite insulator shed aging property and operation time, operation environment and change of parameter regular. It is important for the study of aging mechanis, performance evaluation and operation detection of ac composite insulator.