Effects of statistical characteristics of the output voltage in compact Marx generator on insulation test results

Lightning strikes or flashovers of insulation can result in impulse voltages with very short front times of some tens of ns. Power apparatuses are exposed to these voltages. Steep-front square impulse voltage with high accuracy can be generated by applying advanced pulsed power technology. Nowadays, compact Marx generator (CMG) is used for achieving exact results in tests. Considering the fact that the breakdown of spark gap is a statistical process, the delay times of the closing switches are statistical and voltage-dependent parameters. In this paper, taking the statistical behaviour of the breakdown process in spark gaps into consideration, the statistical characteristics of the output voltage have been studied in detail and its effect on accuracy of insulation tests are described.