The effect of surface area on dielectric performance in vacuum

The ability to withstand high voltages in vacuum is one of the key reasons for its choice as an insulation medium for distribution-class voltage fault interrupters. However, the dielectric performance of vacuum is still not fully understood, sometimes leading to contradictory results. In this paper, high voltage withstand test results are presented. The subsequent location and quantity of the discharge locations on the electrode surfaces are compared with computer electric field models to establish a relationship between electric field, surface area, and likelihood of failure.