The Effect of Paperboard Depression on Discharge under Positive and Negative DC Electric Field

Partial discharge (PD) is considered to be the main reason for insulation aging and insulation failure. In order to research the PD characteristics of oil-paper insulation under DC electric field, the charge and PD under DC electric field was simulated based on two kinds of charge transport model, which used to simulate the discharge process in solid and liquid respectively. The image of discharge and space charge gained by the simulation were explained, and the affect of DC electric field polarity and paperboard depression on the partial discharge characteristics is analyzed. The conclusion of this paper is that PD development under DC voltage shows an obvious polarity effect, and the electric field at the depression is seriously distorted. The results above is conducive to the advancement of PD mechanism of oil-paper insulation.