Study On The Influence To Pollution Flashover Performance Of Insulator With RTV Coating Damage

RTV anti-pollution flashover coating is extensively used on the face of porcelain insulator to raise its flashover voltage recently. There are some kinds of damage like cracks or abscission on the face of RTV coating-insulator which have been used for many year. Due to this phenomenon probably have some influence to insulator’s anti-pollution characteristic, which is worth to intensive study.Based on the existing research results at home and abroad, this paper select XP-160 insulator coated with RTV anti-pollution flashover coating as test sample. A lot of laboratory investigations on the pollution-flashover performances of RTV sample insulator strings with different damage were carried out in the artificial fog room at Key Laboratory of Chongqing University, the main work and conclusion for this paper is as follows:① Measure the liquid static contact angle of RTV surface by using special instrument. Analyze the hydrophobic property of two different RTV coating called S-RTV and P-RTV, and then choose P-RTV to carry out the following experiment.② Study the pollution characteristics of RTV coating insulator in the natural environment. Test the ESDD and the NSDD of XP-160 and RTV coatings under natural contamination, and by analyzing the difference between them, the effect of RTV coating on pollution characteristics of insulator is obtained.③ Study the AC flashover performance of insulator string of RTV coating surface in the state of no damage, continuous sector damage, inner surface damage, outer surface damage. The results show that the pollution flashover voltage decreases with the increase of salt density and area of RTV coating damage. In the same degree of damage area, the flashover voltage value from big to small is respectively: no surface damage> outer surface damage> inner surface damage > continuous sector damage. The variation trend of flashover voltage decreased coefficient k is consistent with the pollution flashover voltage of RTV insulator in different damage location and damage area compared to no damage RTV insulator.④ Study the AC flashover performance of insulator string under the test of RTV coating in intermittent damage. The test results show that the same area in different size under continuous damage of pollution flashover voltage is respectively: a single intermittent damage< two intermittent damage < three intermittent damage < four intermittent damage, and with the increase of damage area, the pollution flashover voltage gradually reduced⑤ Measure the leakage current of RTV coating insulator in flashover process of surface coatings with different damage conditions, and according to the measurement results, the critical flashover currents are obtained. Test results show that the critical flashover current increases with the increase of salt density and RTV coating damage area; In the same degree of damage area, the order of the critical flashover current from big to small is: sector surface damage> inner surface damage> outer surface damage.⑥ The AC pollution flashover process of insulator strings of RTV under different damages were captured, and divided the pollution flashover into four stages including corona discharge, fine filamentous local small arc formation, local large arc formation and local arc development to complete flashover.