The effect of viscosity on the negative streamer inception in PFPE

This paper describes the effects of viscosity on the impulse pre-breakdown phenomena in D40 under nonuniform field condition. Both the streamer inception and the current waveform are measured simultaneously. The viscosity used are 41, 90 and 250 cSt which correspond to the temperature of 20, 7.5 and -4.5°C, respectively. The first appearance of the current pulse preceded the streamer inception in D40. The streamer inception as well as streamer propagation suppressed by increasing viscosity. The effect of viscosity on the first appearance of current pulse appeared in the statistical time lag. The time duration of current pulse activity increased with viscosity. It seemed to be caused by the decrease of mobility of charge carriers in D40 with viscosity