Experiment and modeling of void discharges within dielectric insulation material under impulse voltage

The presence of cavity in motor insulation fed by variable speed drive is one of the sources of partial discharge (PD) occurrence, especially under impulse voltage. This is a serious problem as PD can accelerate degradation of the motor insulation. Therefore, it is important to prevent void discharges from occurring in motor insulation under impulse voltage. In this work, the characteristics of void discharges within dielectric insulation material under impulse voltage were investigated through experiment and modeling. The test object consists of a rectangular void within a polyethylene material. The test object was stressed with different peak magnitude, front time and tail time of the applied impulse voltage. The experimental results were reproduced by simulation results from a void discharge model in insulation material. From the model that was developed, a better understanding on physical parameters that influence the characteristics of void discharges within dielectric material under impulse voltage can be attained.