Effect of Step Duration on Breakdown in Needle-Plane Geometry Under DC Step Voltages

In this paper, dc electrical treeing breakdown experiments are conducted using needle-plane system. Electrical treeing test can be used for the assessment of life estimation of the insulating material by estimating the voltage endurance coefficient and accumulated damage. Damage equalization method (DEM) is used for estimating the life of the dielectric material used in HVDC cables. Breakdown experiments are conducted with progressive voltage steps of different step size. Interesting new results on the role of different step size on breakdown voltage is reported which in turn shows the effect of space charge injection and accumulation. The results from the space charge distribution in a plane-plane geometry justify the authors' results on the effect step size on dc breakdown in needle-plane geometry. The experimental results obtained are compared with data available in the literature for ac electrical treeing tests for different rate of progressive voltage rise.