Studies of impulse creepage discharge in transformer oil

The propagation process of a creepage discharge on the surface of a solid insulator in transformer oil was investigated in detail when impulse voltages with various rates of rise T/sub f/ of the wave front are applied to a point electrode. The shape and size of the Schlieren figures agree well with dust figures. The propagation of density changes (steamer-like density changes) corresponds to the current and the charge waveform. The effect of T/sub f/ on their propagation is also discussed.>