New investigation on pseudospark discharge and quenching phenomenon at zero current

These studies, carried out on the pseudospark discharge, show its high ability to open a circuit at zero current. The interesting results are linked to the diffuse discharge mode, and allow avoidance of the development of anodic spots at high peak current above 40 kA. In these experiments, after a pulse current of 18 kA and 225 /spl mu/s duration, the rate of reapplied voltage is 18 kV//spl mu/s and the peak of withstand voltage is 18 kV. This ability depends strongly on the electrode conditioning. The authors obtained the best results with a number of shots up to 200 and a rate current lower than 210/sup 8/ A/s. They believe that the values of the rate of current at zero current (conduction phase) have a great influence on the opening switch performance. They investigate other characteristics, such as the dimensions of the cavities, the hole diameter, the gap and the pressure, in order to increase performance. A CCD camera allows investigation of the conduction phase and the recovery phase before and after zero current crossing.