Counter leaders in systems with a dielectric barrier

Features of the breakdown of the air gap with a large-diameter solid dielectric barrier with pulse voltage supply are considered. Usually the preliminary closure of the gap by streamers is necessary for the breakdown of gaps with a length of 5–500 cm; however, in the considered systems the closure is hampered by the large length of the path in air by-passing the barrier. The results of this study make it possible to assume that at a large diameter of the barrier the streamer-leader transition occurs on both sides of the barrier, then the pair of leaders propagates along the barrier on its different sides to the closure at the edge of the barrier. The possibility of the streamer-leader transition at moderate voltages (50–400 kV) can be provided by the considerable charge value transferred through the streamer channels on the surface of the dielectric barrier. The accumulation of the considerable charge on the surface of the barrier is possible due to the formation of a pair of spots of the heteropolar surface charge, a kind of an electric capacity.