Evaluating the relationship of breakdown voltage and material losses of different types of electrodes by SEM

Abstract

This research was presented the measurement of the breakdown voltage of air with 4 sets of electrode experimenting kits which consisted of rod gap electrode type, needle gap electrode type, spherical gap electrode type and partial spherical gap electrode type. The result showed that the highest breakdown voltage occurred in a partial spherical gap electrode type, followed by spherical gap electrode type, needle gap electrode type and rod gap electrode type. It also showed that the greater the gap distance was, the higher the breakdown voltage occurred. The breakdown voltage varied in proportional to the gap distance. The surface damage of the needle gap electrode after the breakdown voltage experiment was characterized by SEM and revealed that cross-sectional area of electrode’s sharpness diameter increased as the gap distance and breakdown voltage increased. This also showed that the cross-sectional area of electrode’s sharpness diameter was directly proportional to the gap distance and the breakdown voltage. The physical characteristic of the surface of the needle gap electrode was rough with cracks and deep holes. In conclusion, based on this research, the deterioration of electrical equipment caused by accumulated partial discharge activities over time would eventually cause insulation breakdown and permanent damage of the equipment.