Nanosecond surface discharge with voids in dielectrics

Source abstract

Surface dielectric barrier discharge (SDBD), a partial discharge (PD) on the surface, is a serious threat to the safe operation of insulators. During the discharge, the streamer propagation will charge the surface, and result in different polarization to the dielectric corresponding to intricate dielectric configuration in and outside the dielectric. In this work, we analyse the results of negative SDBD streamer propagating on a flat surface with voids inside the dielectric. We found that the polarization inside the dielectric enhanced the electric field strength of the air in voids, resulting in partial discharge from the voids’ wall, showing a volume discharge accompanied with surface discharge in the voids. With the number of voids increased, the volume partial discharge appeared in sequence along the streamer’s propagating direction. The intensity of volume partial discharge in the voids is dependent on the polarization degree adjacent to the voids’ wall inside the dielectric. Besides, the shape and propagating speed of the discharge streamer on the flat surface varied with the quantities of voids, caused by the local electric field changing in front of streamer head.