The Effect of Residual Charges on the Discharge of the Long Air Gap with a Floating Conductor Under Positive Switching Impulse

The discharge experiment of the long air gap with a floating conductor is an effective experimental method in power transmission and distribution engineering. In order to avoid the effect of residual charges on the experimental results, the operators need to ground all the experimental devices before each set of experiments according to the normative process, which causes an increase in work intensity of the operators and the time for experiment. In this article, the comparative experiment on the effect of residual charges on discharge parameters is carried out. The result indicates that the residual charges have a slight effect on the breakdown voltage, the maximum voltage deviation is only about 5.72%, and the position of the minimum breakdown voltage of the gap isn't changed. The results can contribute to simplifying the experimental operation and shortening the time without causing inaccuracies.