Measurement and modelling of partial discharge behaviour in a spherical cavity within a solid dielectric material as a function of cavity diameter

Partial discharge (PD) measurement is an important diagnostic tool for insulation system assessment, which can be used to determine degradation of the insulation. Thus, PD monitoring has become an essential tool in assessing the performance of insulation materials and the modelling of PD events has been used widely to attain a better understanding of this phenomena. In this paper, a Finite Element Analysis (FEA) model for simulation of PD activity in spherical cavities of different diameters within a homogeneous dielectric material has been developed. The model has been used to study the influence of spherical cavity size on PD activity within a solid dielectric material by comparison of the simulation and measurement results. It was found that certain parameter values in the model vary for different cavity sizes. Critical parameters affecting PD activity for different spherical cavity sizes have been identified.