Effect of voltage reverse time on space charge and transient field in polyethylene

Adopting pulsed electro-acoustic method space charge measurement method, space charge profiles and maximal transient fields of polyethylene (PE) films were measured at room temperature (ΔT=0°C) and under temperature gradient (ΔT=40°C), when DC stress of -50 kV/mm was applied for 2 hours and then voltage polarity reverses to stress of 50 kV/mm with the time of 20 s, 30 s and 60 s respectively. The test results show that the faster the voltage reversal at room temperature the higher the maximal transient field. However under temperature gradient (ΔT=40°C), the faster the voltage reversal the lower the maximal transient field, and the time reaching the maximal transient field decreases with the increase of voltage reverse time gradually.