A mechanism of pulse breakdown evolution in polymeric films

We present the results of an experimental study of the pulse electrical strength of polyethylene terephthalate and polypropylene films when they are subjected to a single electric pulse. It has been found that the breakdown of these films is possible both at the front and at the plateau of the pulse, and the probability of breakdown at the front increases with pulse amplitude. We recorded a jump in the durability of the films at the transition from breakdown at the front to breakdown at the pulse plateau. It is shown that the processes that prepare the film electrical breakdown develop faster at the pulsefront than at the plateau. We discuss a possible physical mechanism to explain this effect.