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

Impulse voltage conditioning is the key to improving the insulation performance of vacuum interrupter, which is closely related to the breakdown (BD) charge. The objective of this article is to propose a method for adjusting the optimum BD charge during the impulse voltage conditioning process for vacuum interrupter, based on the experimental study on the conditioning characteristics of vacuum gaps under different BD charges. In experiments, a pair of copper sphere-plane electrodes in a commercial vacuum interrupter was selected. A standard lightning impulse voltage (LIV) was applied. The limiting resistance
${R}_{\text {L}}$
ranged from 0 to 10
$\text{k}\Omega $
. The experimental results reveal that the BD charge has a significant impact on the BD voltage of vacuum gaps in the conditioning process. For copper electrodes in a vacuum with a gap distance of 2.0 mm, the optimum BD charge
${Q}_{\text {BD}}$
in conditioning is determined to be 1.6 mQ. Under the optimum
${Q}_{\text {BD}}$
, the BD voltage in the saturation region reaches 135.3 kV, which is 66.4% higher than that without the adjustment of
${Q}_{\text {BD}}$
. Moreover, an adjustment method during the impulse voltage conditioning process is proposed, in which the optimum
${Q}_{\text {BD}}$
is judged by the maximum
${Q}_{\text {BD}}$
on the premise of a low scatter of BD voltage under the increasing
${R}_{\text {L}}$
.