Arcing voltage for a medium-voltage air load break switch

Abstract

Air is an environmentally benign and attractive alternative to SF6 as arc quenching gas in switching devices for modest current and voltage ratings. Several interruption tests with a simple air medium-voltage load break test switch have been carried out to investigate the arc and the arcing voltage behavior for different circuit and switch design parameters. During the first half-cycle after contact separation, the arc voltage is typically 100 - 200 V. Approximately 50 μs before current zero the arc voltage increases in magnitude, before collapsing at current zero. The arc voltage increases with increasing contact gap, with decreasing current, and with increasing air flow. The arc voltage measurements from this work are believed to be suitable as experimental reference for verifying results from computational current interruption models.