Optical characteristic of vacuum surface flashover of grooved dielectrics

Using an ultra high-speed framing camera Hsfc-Pro, the development of vacuum surface flashover of grooved dielectrics is investigated. Variations in flashover images between the plane and grooved dielectric samples are compared. Then the capability of grooved dielectrics in strengthening the insulation strength is discussed. It is found that the introduction of periodical grooves alters obviously the flashover channel. With respect to the plane samples, their flashover channel develops along a straight line across the A-K gap, while for the grooved dielectrics, their flashover channel locates at the circular edge of the samples. Such a bended path increases obviously the flashover distance, therefore, the flashover time delay of grooved dielectrics is at least /2 times that of plane ones. This certifies that grooved dielectrics can increase promisingly the insulation strength without increasing their physical dimension.