Impulse Surface Flashover Development with Transient Charging on Solid Insulators in Vacuum through Streak Image Observation

As one of the most important technical issues for the advanced vacuum circuit breakers and vacuum interrupters, the suppression of surface flashover on solid insulator in vacuum is needed. To clarify the mechanism of the vacuum surface discharge, charge activities during the development of surface flashover on solid dielectrics have been investigated. In addition to fast-framing photography and real-time measurement with electrostatic probes on the grounded electrode behind the alumina dielectrics, we newly introduced a streak camera and measured the ultra-high speed streak image of the surface flashover development. Experimental results of streak images revealed that light emissions concentrated around the cathode at the start of the flashover development due to explosive electron…