Short interval measurement of transient space charge distribution and electrical breakdown in polymer film in high temperature region

Space charge dynamics in low-density polyethylene (LDPE) films were observed by the pulsed electroacoustic (PEA) method during breakdown test at various temperatures. In order to investigate the intrinsic electrical breakdown phenomena, the applied electric field was increased 3MV/cm in 150ms, and kept constant until breakdown, or 300ms at the longest. Space charge profiles were measured at 1ms intervals. A significant positive charge propagation into the sample was observed only immediately before the breakdown at 90/spl deg/C. These measurements revealed that the positive charge behavior is related to the breakdown phenomena.