Bipolar DC corona discharge from a floating filamentary metal particle

The motion of a filamentary particle and also the discharge from a particle have been extensively investigated for the development of prevention and protection method in a gas-insulated switchgear (GIS). The particle showed several different patterns of motion; such as simple standing, precession motion, jumping up-and-down, and so forth. In either case of such motion, it depends on corona discharge from the particle itself. Since this motion cannot be explained with only monopolar discharge from one end of a particle, bipolar discharge from both ends of a particle occurring simultaneously have been investigated by applying the floating particle method. The particle length and the gap between particle and electrode were chosen as parameters. From experimental results, several interesting features were obtained. the curve of bipolar corona current lays between negative and positive ones of monopolar curves. There is current jump at the threshold voltage that seems to be a new feature of corona current from a filamentary particle. So far, the experimental results indicate that this threshold voltage is not a function of a particle length, but it could depend slightly on length. Flashover voltage is a function of particle length and gap. It decreases with length and increases with gap