Observation of corona and flashover on the surface of composite insulators

The complexity of insulators´ structure make it difficult to control the accumulation of water droplets on the shed surface and to observe the discharge. Locally, the water droplets on the shed surface of composite insulators are in relatively uniform electric field. In this paper, a model of composite insulators was designed to simulate the local uniform electric field and a high-speed video camera (Motion Scope^® PCI 2000 S) was used to record the phenomena of testing. The distortion and movement of water droplets that were discharging on the surfaces of sample insulators was observed and the process of the discharge is analyzed. At last, the possibility of water droplet induced corona and its influence on composite insulators´ hydrophobicity were discussed.