Computer investigation of voltage effect on electrical treeing

Abstract

The propagation of electrical tree channels into dielectrics with the subsequent breakdown of the electrode gap is one of the main causes for failure of high voltage insulation systems. The tree growth occurs s in regions of high electric field due to the accumulation of dielectric material damage, The damage is caused by partial discharges within the gas-filled tree channels, Dissado and Fothergill [1]. The parameters of the partial discharge activity depend on the electrical tree shape and growth mode. The partial discharges and the tree growth are simultaneous and selfconsistent processes resulting in insulation degradation. It is desirable to have a self-consistent model, which involves both electrical tree growth with local electrical fields and partial discharge events within the growing tree channels. This self-consistent model has been previously introduced in order to describe the simultaneous tree growth and partial discharge activity in solid insulation under AC voltages by Malinovski et al [2]. In the present paper the suggested approach is extended to more thoroughly investigate the effect of applied voltage on the spatial and temporal development of electrical trees and partial discharge characteristics.