Leakage current analysis on RTV coated porcelain insulators during long term fog experiments

RTV silicone rubber coatings have successfully helped traditional glass and porcelain insulators to avoid serious pollution flashover accidents. This paper presents experimental results of pollution withstand properties of partially coated porcelain insulators. The influence of the position of insulators was also evaluated. In order to evaluate the influence of both the position of the insulators and the surface status (hydrophobic and hydrophilic), three salt fog test series which combined these two factors were carried out. Leakage current was monitored during these tests as an indicator of the long term performance of the insulators. Finally, the measurement and analysis of the change of SDD on insulators with different positions before and after these tests was also performed to establish the relationship between insulator positions and their long term performance.