An investigation into the effect of varying the main field and local field on the PD characteristics of nanofilled polypropylene films

When a rod - plane electrode system with a dielectric barrier is subjected to a power frequency voltage, the progression of partial discharges is dependent on the combined field due to applied voltage and local field caused by residual charges resulting from earlier partial discharges. The goal of this paper is to investigate the effect of variations in main (applied) field in comparison to variations in local field due to space charges on the progression of surface partial discharge behavior in polymer nanocomposites. In the first set of experiments, keeping all the other conditions constant, the effect of variation in gap spacing on the partial discharge behavior and its effect on depth of erosion in unfilled polypropylene is studied. In the second set of investigations, keeping the main field constant, composition of the polymer nanocomposite (i.e. content of the nanofiller) of the dielectric barrier is varied thereby altering the local fields by virtue of their difference in response to PD occurrence. The results of our investigations and their analysis is presented.