The Reason And Presentaion Research Of Synthtic Insulator Flashing Over Under Working Condition

The composite insulators have some good performances, such as high intensity, high ratios of strength to weight, no zero values, vandalism resistant, and high polluted flashover voltage. However, accidents in process take place from time to time, even no obvious fault point can be found out after some accidents. Hence, it is important to research the unknown flashover of the composite insulators. This paper, based on a great deal of references, starts with material, structure, processing craftwork, experience, experiment result to synthetically analyze the causes of the flashover fault of the composite insulators. And the flashover reason is the dry-arc distance too short. Another reason is in some severe weather, hydrophobicity of silicone rubber was difficult to transfer to the pollutant, and was likely to degrade partly or be lost completely as result of surface discharge. The choose of leakage distance is illogical. So we suppose that in those areas where the thunder happens frequently the dry-arc distance should be added up to 1050mm from original 1000mm in 110kV line. Unknown flashover of the composite insulator takes place mostly because that the silicon-rubber absorbs moisture under the long-term dirty and wet circumstance, which causes the surface hydrophobicity to vanish excessively; the other reasons are that the leakage ratio-distance are choiced irrationally, or some riband is adhere on the insulator surface. Though contaminated by coal ash and aluminum-oxygen power, the composite insulator can maintain comparatively high polluted flashover voltage in condition of high altitude and high humidity in Guiyang.