EHD motion induced by reversal of DC polarity in transformer oil

An experimental investigation of the transient EHD (electrohydrodynamic) phenomena induced in transformer oil after reversal polarity of the electric field is reported. It is shown that the electrical behavior of the oil under the reversal polarity depends on the induced motions. The induced motion under the reverse polarity is explained in terms of bipolar injection from the charged layers accumulated in the vicinity of electrode surfaces. The motion has a turbulent character and occurs at low fields. The onset of motion produces an increase and a peak phenomenon of total current. Field distribution is affected by the electric double layer at electrode/oil interfaces