Flashover characteristics of a droplet impacting the silicone rubber surface

The surface discharge of silicone rubber (SIR) is one of the main reasons to accelerate the aging of its surface material in power systems. It is known that static water droplets on the SIR surface can make the flashover voltage substantially fall, while the flashover characteristics of water droplets impacting the SIR surface are unknown. In this work, the dynamic flashover characteristics of the water droplets impacting the SIR surface are studied. When the water droplets impact the SIR surface, they will stretch first and then shrink. The minimum flashover voltage occurs at the moment when the spreading area of the water droplet reaches the maximum, and this flashover voltage drop is nearly 1.8 times that of the static water droplet. When the water droplet begins to shrink, the bright arc first turns into a filament-like arc and then disappears as the water droplet continues to shrink. At the same time, when the droplet falls at a large height, the water droplet will be broken under the action of electric arc force, and the broken water droplet will likely make the static flashover voltage to further fall.