Investigation on discharge development phenomena on D.C. high voltage insulator of two grooves

The local discharge propagation direction towards flashover was investigated using an HV laboratory insulator of two grooves with the same resistance per unit channel length. The experimental results revealed that the presence of a metallic sphere in one channel influenced the discharge propagation direction. In addition to the gradient of potential and current in the pollution, we deduced that the electric field strength around the discharge tip has an effect on the discharge development direction.