Surface Deterioration And Flashover Phenomenon Of Silicone Rubber Insulator Under Multi-Environments

With implementation of western developm ent, completion of Qingzang railway as well as developm ent of ultra-H V tr ansmission project, long distance power transmission lines will be in service under dif ferent environm ents. As polym er insulators are widely accepted in these lines, it is ur gent to investigate the aging and flashover problems under different conditions.UV-light source with dif ferent wave ba nds UV-A, UV-B, UV-C were adopted to simulate the ultraviolet radiation in sun light, after radiation of 5,000 hours, contact angle of silicone rubber specim ens was m easured to get changing tendency of the hydrophobicity. Results showed that afte r being irradiated by UV -C, surface hydrophobicity of the samples declined appr eciably, while samples under UV-A and UV-B did not change apparently . Meanwhile, the rig idity and co lor varia tion of samples were observed.In corona aging experiments, a decompression chamber was employed to simulate different ambient pressures ass ociated with various high-al titude regions. Multi-needles to pla te ele ctrode model were used to produce corona dischar ge. Results sho wed that surface hydrophobicity got worse with the d ecrease of environmental pressure to 60 kPa, whereafter the deterioration situation got better.In rime flashover experim ent, an artificial chamber was applied to simulate the rime conditions with the specim ens vertically hung in the cham ber. Once the rime was condensed on the insulator su rface, the source voltage was applied until th e flashover occurred. Accord ing to visual observation, the flashover process was separated into six stages. Mean value, variance and frequency spectrum of leakage current were analyzed. It is found that amplitude of the current increased and signal pulse got sharper in the process. There were more low frequency components in first three stages while less in the following sections.