Creepage Flashover Characteristics of Oil/Pressboard Interfaces and Their Scale Effects

Creepage flashover characteristics in transformer oil under positive impulse voltage were studied by using models of which the electric field distribution was equivalent to that of actual transformeis. In the experiments, some geometrical parameters concerning creepage flashover and the model scale were varied. It is concluded that the flashover voltage characteristics are determined by electric field strength of the high-voltage electrode surface and stressed oil volume. The scale effect of the creepage flashover was found to be the power of 0.7 of the model scale.