Influence of partial discharge on breakdown of air-polymer composite

The influence of PD on the breakdown of LDPE film under AC voltage was studied using needle-plane electrode system. The purpose of this study is to clarify the effect of magnitude partial on breakdown mechanism of air-polymer composite insulation. The experiments were also performed by resistor (R-Shunt) in front of the sample for control the intensity of partial discharge with varied of voltage application. The time up to breakdown (TB) was measured under different condition. Increasing the voltage amplitude under the same R-Shunt will decrease the TB. However, the PD cannot be considered as the only factor which can decrease the TB, because at the same time the electric field was also increased with increasing the voltage. One way to show the influence of PD on breakdown of polymer film is the increase of magnitude of PD by increasing the R-shunt value. Two regions of TB were obtained with parameters of the magnitude of PD and applied electric field. The first was obtained when the breakdown occurred at the higher electric field. The magnitude of PD little affected the TB. The second was obtained when the breakdown occurred at the lower electric field. The high magnitude of PD gave a lower TB.