Electric Field Strength and Tree Propagation Speed for Electrical Treeing in Silicone Gel

Recently, silicone gel is used to encapsulate electric devices and power modules. Though a silicone gel is insulation, partial discharge is caused by the application of high electric field strength due to the miniaturization of devices, for example. In the gel, the partial discharge trace known as electrical treeing is observed. The generation and propagation of the tree has not become clear. In this research, we investigated the effect of the electric field against development of the treeing, and the influence of the degree of crosslinking of the gel on the tree propagation speed.