High voltage nanosecond breakdown in transformer oil

In this paper, the main influencing factors and results of other research on nanosecond breakdown in transformer oil are introduced. The breakdown characteristics of transformer oil under single and repetitive nanosecond pulses ranged from 1 Hz to 1000 Hz have been investigated. The voltages with single and repetitive pulses are applied and the gap distances are ranged from 0.15 mm to 1 mm. The breakdown waveforms of voltage, current and breakdown time have been measured. The results indicate that the ns-level high voltage pulse breakdown field is much higher than breakdown in DC and AC. The breakdown field value decreases with repetition rate increase. From 10 Hz to 100 Hz, the breakdown field falls quickly. When the repetitive rate exceeds 100 Hz, the field value fall speed is slow. An experiential formula is put forward in this paper which fits transformer oil breakdown characteristics under ns high voltage pulses. The experiment results are discussed.