Simulation of PD patterns due to a narrow void in different E-field distribution

For simulation of Partial Discharge (PD) patterns, a Finite Difference Method (FDM) based model is put forward, in which three significant PD parameters are incorporated, viz. the critical field intensity for partial discharge occurrence Ec, residual field intensity Er and locations of voids inside the dielectric. The void taken in this simulation is a narrow rectangular parallelepiped, i.e. the length and breadth of the void (in the direction normal to the field) is less compared to the height (in the direction of the field) of the void. In this paper, three different electrode systems are considered, viz. Plane-Plane, Point-Plane and Point-Point. The supply voltage is considered to be sinusoidal in nature. PD simulations for different locations of voids inside the dielectric for these three configurations are carried out considering occurrence of PD and residual field to be stochastic in nature for a constant Ec. The inception and extinction of PD, effect of applied voltage on PD, shape of PD patterns in relation to instantaneous released charge amplitude, and the amount of charge which is released due to PDs during a course of time, are studied and reported in this paper.