ELECTRIFIED DROPLET ON CORONA-CHARGED SILICONE RUBBER NANOCOMPOSITE FOR HVDC OUTDOOR INSULATOR

摘要

In HVDC transmission lines, corona could occur even on well designed hardware and insulators, which can significantly damage and inject the charge in the surface of insulators. Once a charged droplet deposited on the surface, the insulation performance of the insulators will be affected. In this research, the characteristic of an electrified droplet on corona-charged silicone rubber (SiR) nanocomposite surface was observed under dc voltage stress. The samples were made by dispersing nano-scale SiO2 powdered in SiR with the weight ratios of 0, 1, 2, 3 wt%, and were charged for 5 minutes under a dc corona discharge system based on needle-plate electrode. Then the flashover test was carried out under a dc stress between two aluminum plate electrodes. The effect of nanoparticles weight percent on the surface charge density and the surface charge on contact angle was obtained. The relationships among the charge density, the contact angle and the flashover voltage via the droplet were obtained. The results show that charged droplet deposited on charged surface has a negative effect on the insulation performance of insulators and nanoparticles filled in the SiR can make the flashover occur even at lower voltage.