Impulse breakdown of small air gap in electric field Part I: Influence of barrier position

Abstract

The influence of barrier position on breakdown voltage in air dielectric has been investigated. Needle and Cone positive point electrodes were used and the effects of electrode curvature on barrier position for maximum breakdown voltage were compared, with air gap for the point to plane electrode fixed at 10 cm for all the tests. The breakdown probability was found for barrier position, and at every barrier distance, the breakdown voltage differed. The position for maximum breakdown for needle electrode was in the range of 28 - 30 % from the poi-nt electrode. The position for optimum breakdown for cone electrode was 50 % from the point electrode, and the deviation originated from the electrode configuration. The effect of defective barrier was tested by introducing holes of different diameter at the barrier centre, and the maximum breakdown voltage was affected depending upon the diameter of the hole on the barrier.