Effect of electronegative gases on prebreakdown conduction-current pulses in transformer oil

Results are given of the effect on prebreakdown conduction-current pulses of dissolving air, oxygen (O2) and sulphur hexafluoride (SF6 in transformer oil. The pulses were recorded during the experiments on magnetic tape and subsequently subjected to statistical analysis. It was found that during the stress-conditioning pulses of different magnitudes behaved differently. Air or O2 in solution in the oil resulted in a pronounced quenching effect on the pulses. A similar effect was observed with SF6 in solution, but after a breakdown a drastic change in the behaviour of the pulses was noticed.