The very fast transient over-voltage/over-current generated during switching operation of disconnector may result in a significant threat to the reliability of power grid. However

there is a lack of research on the variation characteristics and law of electromagnetic interference in the very fast transient process of the disconnector. In this paper

the transient voltage a

nd current data of opening and closing small capacitive current test of disconnector is taken as the base

the characteristic data of the corresponding macropulse and monopulse waveform is extracted to perform comprehensive statistical analysis of the transient waveform characteristic data by way of probability density function fitting and Kolmogorov-Smirnov (

K

S

) test of the sample cumulative empirical distribution. The results show that the probability density of macropulse waveform duration of opening and closing operation follows generalized extreme value (GEV) and inverse Gaussian distribution respectively. The maximum peak of VFTO and VFTC monopulse is 50 kV and 370 A respectively

the rise time is in the range of nano- and micro- seconds respectively. The monopulse interval time is ms level. The number of monopulse of opening and closing operation shows normal distribution. The research result can provide scientific evidence for the development of strong electromagnetic disturbance standard test source and the formulation of electromagnetic compatibility standard tests at system level.