Influence of Auxiliary Electrode on Discharge Characteristics in SF₆ Gas under Pulse Voltages

Abstract

The effect of a corona initiated from a needle electrode, which located near a sphere electrode relative to a plane electrode, on the discharge of the sphere-plane gap under pulse voltage was investigated in SF₆ gas under pulse voltages. The corona initiated at the needle tip was differed with a resistance connected. Under the pulse with risetime of 0.5μs, the discharge voltage of the sphereplane gap increased considerably with increasing resistance and finally reached a maximum at about 5MΩ and then decreased with continued increase in the resistance. The breakdown voltage under the slow rising pulse was scarcely influenced with the resistance used in this experiment. The mechanism of the discharge of the sphere-plane gap in complex electrode systems as mentioned above was discussed by the results obtained with an ultrahigh speed digital framing camera.