Adjustment Method of Optimum Breakdown Charge During Impulse Voltage Conditioning Process for Vacuum Interrupter

Impulse voltage conditioning is the key toimproving the insulation performance of vacuum inter-rupter, which is closely related to the breakdown (BD)charge. The objective of this article is to propose a methodfor adjusting the optimum BD charge during the impulsevoltage conditioning process for vacuum interrupter, basedon the experimental study on the conditioning charac-teristics of vacuum gaps under different BD charges.In experiments, a pair of copper sphere-plane electrodes ina commercial vacuum interrupter was selected. A standardlightning impulse voltage (LIV) was applied. The limitingresistance R(L )ranged from 0 to 10 k Omega. The experimen-tal results reveal that the BD charge has a significantimpact on the BD voltage of vacuum gaps in the condi-tioning process. For copper electrodes in a vacuum witha gap distance of 2.0 mm, the optimum BD chargeQBDinconditioning is determined to be 1.6 mQ. Under the opti-mumQ(BD), the BD voltage in the saturation region reaches135.3 kV, which is 66.4% higher than that without the adjustment of Q(BD). Moreover, an adjustment method dur-ing the impulse voltage conditioning process is proposed,in which the optimumQBDis judged by the maximumQBDon the premise of a low scatter of BD voltage under theincreasing R-L .