Modeling of Partial Discharges from a Spherical Cavity within a Dielectric Material under Variable Frequency Electric Fields

Partial discharge (PD) is a discharge event that does not bridge the electrodes within an electrical insulation system under high voltage stress. In high voltage components, the measurement of partial discharge is used in the performance assessment of an insulation system. Through modeling the discharge process a better understanding of the phenomena may be attained. Previous studies have considered the modeling of PD activity from a cylindrical cavity. However, this is a limited approach as the most common types of cavities found in the insulation materials are either spherical or ellipsoidal. This paper describes the development of a model for a spherical cavity within a homogeneous dielectric. The model developed has been used to study the influence of the applied frequency on partial discharge activity and obtained results are presented.