Lightning Impulse Long Delay Breakdown of Centimeter Vacuum Gaps.

This paper presents an experimental investigation into the breakdown voltage fall time t f of lightning voltage breakdown of 2–4 centimeter vacuum gaps having a long breakdown delay time t d (>30 µs). The results show that the average 50% breakdown voltage fall time t 50 decreases with increasing vacuum gap. It is considered that the lightning impulse breakdown of the centimeter vacuum gaps with a long breakdown delay time may be initiated by the interaction between the cathode thermal processes and the micro-particles phenomena. The increase of the electrode diameter and the decrease of the electrode radius of curvature may contribute to the decrease of the breakdown voltage fall time. [ABSTRACT FROM AUTHOR]