3D modelling of partial discharge within epoxy-resin dielectric of cables for distribution and transmission networks

This paper presents a 3D model of Partial Discharge (PD) phenomena, based on Finite Integration Technique (FIT), using the CST STUDIO® software. PD modeling is useful to study discharge event phenomena and to analyse the critical parameters that characterize its behaviour. The knowledge of PD phenomena inside electrical insulation is an important issue to assess the insulation condition and its degradation state, obtaining information about its defect types and the possible risk of failure that can occur. PD models based on numerical methods have the advantage to give an insight into the discharge events, to describe non-uniform E-field distributions inside the material and the charge distribution on the surface of the defects and on the electrodes. In this paper, a model of PD event inside an air disk inclusion within epoxy-resin dielectric of cables for distribution and transmission networks is presented. The E-field distribution is calculated in relation to two different positions of the defect inside the dielectric and the displacement current density on the electrodes is evaluated together with the conduction current density inside the void. The proposed study is the first step of a work in progress that aims to describe the propagation of PD signals in distribution and transmission networks.