Abstract
The breakdown time lags in PPS were measured in the ns and minute ranges and in a wide temperature range (-196 to 200°C). The temperature dependence of the electric breakdown strength became stronger at the longer time elapsed after the voltage application. With increasing the test temperature, the electric breakdown strength decreased from the maximum value at -196°C to the minimum value at 20°C, increased to a peak value at 100°C, and then decreased again. The time lags were normally distributed in both time ranges although the distribution of time lags in the ns range was exponential type for all of the seven kinds of polymeric insulating films, which were previously reported. The normal distribution of time lags suggests that the breakdown was not caused by a stochastic event such as an avalanche breakdown but by the process which started just the moment of the application of a voltage, regardless of the time range. The results in the minute range show that the breakdown was caused by the field distortion due to space charge, though the breakdown mechanism in the ns range was still obscure.
