Finite Element Modeling of Partial Discharge Activity within a Spherical Cavity in a Solid Dielectric Material under Fast, Repetitive Voltage Pulses

Accelerated aging of insulation systems used in different apparatus under fast, repetitive voltage pulses is the most significant barrier to benefit from wide bandgap (WBG) power electronics. Frequency and slew rate which are higher for WGB devices than Si-based ones are two of the most critical factors of a voltage pulse, influencing the level of degradation of the insulation systems that are exposed to such voltage pulses. Finite element analysis (FEA) has been widely used to study partial discharge (PD) behavior under a power frequency (50/60 Hz) sinusoidal waveform within cavities in a solid dielectric. However, the new technologies urge the need to utilize it under square waveforms. In this paper, a FEA model of PD activity is developed. The model is used to investigate the change in the electric field distribution before and after PD occurrence and the impact of different involved parameters when repetitive voltage pulses are applied to the dielectric.