Calculation of Impulse Flashover Voltage of a Water Column

The impulse flashover voltage of a water colume has been calculated using numerical techniques, while considering the constriction of the water column and the dynamic behavior of the discharge propagating along a water surface. The computed values have been compared with the experimental results obtained under 1/5, 1/50, 1/500, 1/5000, 1/50000 impulse voltages of both polarities for water columns having varying total lengths, flow rates, and initial unit length resistances. Agreement between the measured 50% and the calculated flashover voltages has been obtained especially for shorter wave tail durations at negative polarity.