Creepage discharge characteristics over solid-liquid interfaces with grounded side electrode

The properties of streamers traveling over the surface of oil-immersed solid dielectrics were experimentally studied under lightning impulse conditions. Streamer polarity and the position of a grounded side electrode significantly affected the relationship between the streamer extension length and the applied voltage. The solid surface charging had also a large effect on the streamer propagation. However, the streamer propagation properties showed a consistent dependence on the potential at solid-liquid interfaces. In addition, the potential drop inside the streamer channel was measured as a function of normalized streamer length. The curve revealed that the potential drop was increased drastically within the region of ~20% from the streamer tip. The streamer appeared to progress with a constant mean velocity.