Impulse Breakdown Characteristics In Air In The Presence Of A Local Spark

Abstract

In this paper, we study the flashover phenomena in air gaps containing floating metallic objects. The effect of a local spark on the impulse breakdown characteristics of a model gap arrangement which simulating a gas insulated switch (GIS) has been experimentally investigated. The three electrode gap consists of two conical rods facing each other together with a ground plane (or conical rod with the angle of the tip being varied). One of the horizontal rods is energized and one is left floating. Possible mechanisms by which the local spark may influence the main breakdown voltage are discussed. The possible mechanism by which the local spark initiates the main breakdown would seem to be associated with the high electric field around the Jocal spark channel enhanced by unnecessary streamers protruding from its surface.