Local corona behavior and creeping discharge on (needle-dielectric, semiconductor) composite electrodes

Abstract

SUMMARYThis paper describes local corona behavior and creeping discharge on composite electrode systems in N 2 . The composite electrode consisted of a needle contacted with a borosilicate glass or a ZnO disk on a needle-plane configuration. The discharge voltages increased when the needle was in contact with the glass with increasing creeping distance (L) from the needle tip to the bottom of the disk. The discharge voltages showed a reversed polarity effect beginning at L = 4 mm. In the case of a needle in contact with ZnO, the discharge voltage increased with distance until L = 2 mm, but decreased beyond L = 2 mm. Observation using an ultrahigh-speed camera showed that the discharge behavior was different for the glass and for the ZnO. Corona photographs taken by a camera with an image intensifier showed that the corona was generated at the triple junction in the case of ZnO. The differences in discharge voltage characteristics and the discharge behavior between the glass and ZnO were associated with the corona properties.