Non-Sustained Disruptive Discharge Phenomena After Current Interruption in Vacuum Gap

Though the generation mechanism has not been clarified, nonsustained disruptive discharges (NSDD) sometimes occur when the voltage is impressed for a certain time between vacuum gaps after the current is interrupted. So we studied for clarifying the generation factor of this phenomenon, the contact material used is CuCr, CuW, and AgWC. We impressed the voltage (20 kV ~ 30 kV) of AC 50Hz after current interruption (1 kArms ~ 8 kArms), and checked the generating frequency of NSDD. After the current interruption test, we measured contact surface roughness and field emission current. As a result, we understood that metallic particle must be related to these phenomena