Effect of Profiled Surface on Streamer Propagation and the Corner Effect

Streamer behavior near dielectric surfaces is an important characteristic of gas-solid electrical insulation systems. This paper presents the numerical study on the propagation of positive streamers along dielectric surface with different roughness and shape in ambient air. Each surface is designed to have different roughness but the same streamer propagation length to exclude the effect of elongated profiled surface on the streamer. So other factors that involved in streamer propagation on profiled dielectric surface could be analyzed. When streamers propagate to the corner on a surface with concaves, the radius of streamer increases and the electric field in front of the streamer decreases. The phenomenon is called corner effect. With the increase of roughness, the radius of the streamer becomes larger and the electric field in front of the streamer becomes smaller at the corner. Meanwhile, the increase of the roughness results in an inhibition on the streamer development. Moreover, it is found that the streamer accelerates when it descends on the slope and decelerates when ascending. When the streamer propagates on a dielectric surface with convexities, the streamer development is also impeded. However, the variations of streamer radius and electric field at the corner show different trend as that in a concave.