Flashover Performance of Electrodes With Different Roughness Coated by Dielectric Film

The design and operation of many pulsed-power devices are affected by surface flashover of insulator, resulting in reduction of voltage and current output; therefore, the physical research under the corresponding parameter is limited. Since the primary electron emission plays a critical role in the flashover process, methods that can prohibit electron emission from the cathode are expected to improve flashover performance effectively. In this article, stainless steel electrodes of different roughness are coated with alumina films by means of thermal vacuum evaporation, and the surface flashover performance is studied and compared with untreated electrodes. The results show that the first breakdown voltage, condition voltage, and hold-on voltage of coated electrodes increased by 39%, 26%, and 39% for Ra 0.8, and the increase of Ra 3.2 was quite limited. To substantially improve the flashover performance, it still needs to figure out other factors which will affect the electron emission threshold.