The Influence Of AC Corona On The Hydrophobicity Loss And Recovery Characteristic Of RTV Coating

Room temperature vulcanized (RTV) silicone rubber coating has become the preferred coating in the anti pollution flashover work of the power system, that’s because of its superior hydrophobicity and migration of hydrophobicity. The hydrophobicity quality of the RTV coating is directly related to the anti pollution flashover performance. In project, under the extremely uneven electric field, the corona discharge can cause local decline or loss on the coating surface, so it is necessary to study the he effect of AC corona on the of the RTV coating.In this paper, the contact angle method is used to characterize the hydrophobicity, and the test of of the silicone rubber were carried out based on the AC corona aging test system. It include the comparison of RTV and HTV under different times and different voltage amplitude, effect of temperature and repeat corona on corona, and the comparison of hydrophobicity loss and recovery of the corona point and the non-corona point after stain and soak the corona sample.From the study we could see, the static contact angle is applicable to clean and corona sample, and for the stain and soaking samper the static and the dynamic contact angle together can characterize the hydrophobic state better. Under the same corona condition the hydrophobicity loss of the RTV is slower than that of the HTV, but the recovery rate is faster. Along with the higher temperature, the recovery is slower of the RTV, but the recovery is faster.For samples immediately being contaminated after corona, under the same concentration, in the initial stage after being contaminated the contact angle of the non-corona point was larger than that of the corona point, and the hydrophobicity recovery time had a trend of increase along with the increase of the corona time. But for samples being contaminated after the hydrophobicity recovered completely, under the light or the heavy pollution, the hydrophobicity recovery difference between the corona point and the non-corona point was not obvious. For samples immediately being soaked after the corona, the contact angle of the non-corona point declined along with the increase of soaking time, but the corona point was different. As for the corona point, the hydrophobicity existed a certain degree trend of rising (samples of corona l0min and4h, soaking in the dilute solution), especially in long time corona (corona24h) it was much more obvious. In the recovery process when the samples were taken out of the solution, the hydrophobicity recovery of the non-corona point was much better, it was obvious in the initial recovery phase, and the hydrophobicity increased gradually along with the increase of the recovery time. The repeat corona can lead to a little quicken of the hydrophobicity loss, and a little increase of the hydrophobicity recovery time.