Study on transformer oil breakdown under repetitive nanosecond pulses

In this paper, the results of repetitive nanosecond breakdown in transformer oil are introduced. The breakdown characteristics of 25# transformer oil under repetitive nanosecond pulses ranged from 1 Hz to 1 000 Hz and the gap distances range from 0.3~1.5 mm have been investigated. The breakdown waveforms of voltage, current and breakdown time have been measured. The results indicate that ns level high voltage pulse breakdown field is much higher than breakdown in DC and AC. The breakdown field value decreases with the repetitive rate increases. From 10 Hz to 100 Hz, the breakdown field falls quickly. When repetitive rates exceed 100 Hz, the field value fall down speed is slow. The experimental results show that the lowering of the breakdown elactric field under repetitive pulses conditions