Effect of variation in main field and nanoparticle content on the partial discharge characteristics of polypropylene nanocomposites

Abstract. The effect of varying the main and local field on the partial discharge characteristics of polypropylene film is studied by analyzing the temporal behavior of partial discharge parameters. In the first set of experiments, keeping the applied voltage constant, the gap spacing is varied altering the applied field. When the gap is relatively small, discharges appear in quick succession deepening the craters in front of the rod tip where space charges are widely distributed, precipitating discharges of wide range of amplitudes. At relatively larger spacing, the discharge behavior is largely controlled by electric field distribution. In the fixed gap experiments, the local field is varied by introducing polymer nanocomposites that have different filler content. For a fixed gap and constant voltage, discharge magnitudes are lower in samples with nanofiller content below the percolation threshold than in the base polymer. The scatter in discharge magnitudes is lower in samples with nanoparticle content below the percolation threshold than in samples with nanofiller content above the threshold. The major conclusion is the maximum advantage of adding nanofillers is gained only when the particle content is below the percolation threshold.