A study of charged droplets on silicone rubber nanocomposite surafce under DC voltage stress

The 800kv dc transmission line is now in experimental operation in china. Recently, polymer nanocomposites have attracted wide interest as a method of enhancing polymer properties, which may apply as insulators in the UHV and EHV transmission line. A number of papers have reported enhanced electrical performance (aging and breakdown) of silicone rubber nanocomposite, but little attention has been focused on charged droplet on nanocomposite surface of silicone rubber under dc voltage stress. In this research, charge quantity of droplet and contact angle of the charged water droplets deposited on the surface of silicone rubber nanocomposite was observed. The samples were made by dispersing nano-scale SiO₂ powdered in silicone rubber with the weight ratios of 0, 1, 2, 3wt%, and were put under needle electrodes with dc voltage for 5 minutes before the test. Charged water droplets were dropped on the surface, and the surface charge potential was measured. Then the experiment was carried out under dc stress between two plate electrodes. The relationship among the surface charge of sample, the charge quantity of droplet, the contact angle, and the flashover voltage were obtained. The result shows that charge quantity of droplet and surface charge density has significantly effect on contact angle of the droplet and flashover voltage of samples.