Influence of Paper Surface Morphology on Streamer Propagation at Oil-Paper Interface

Partial discharges (PDs) can erode insulating paper, altering its surface morphology. This morphological transformation, subsequently, influences the evolution of further PDs. This study constructs a numeric streamer model, integrating the hydrodynamic drift-diffusion model in oil, the bipolar charge transport model in the insulating paper, and the Ohmic model for interface charge transfer. The model serves to explore how changes in surface morphology affect the discharge process. Simulation results demonstrate that morphological alterations on the profiled surface accelerate PD development and augment surface charge accumulation on the insulating paper. The generalized concave crater’s charge accumulation effect results in an intensity increase at the bottom of the electric field and a decrease at the top of the profiled surface. The positioning of concave and convex features on the surface primarily impacts the amplitude of local electric fields, which decreases as the distance from the arc center increases. The distortion rate of the electric field in a convex or concave surface is a time-independent characteristic, solely reliant on surface morphology. Given identical surface morphology, a greater value of surface roughness suggests a higher capability for electric field distortion. The results in this article contribute to a better understanding of surface morphology’s effect on the streamer propagation process.