Factors affecting transformer oil flow electrification in electric power apparatus

The factors affecting the generation and accumulation of static charges due to oil flow are investigated and discussed. These factors are oil temperature, flow rate, type of electric field applied, moisture content, anti-static additives, aging, and type of material interfacing with oil. In addition, a comparison between the calculated and the measured values of the relative streaming currents is carried out. The streaming electrification phenomenon is shown to exist for both energized and unenergized systems, and the streaming current increases in proportion to the increase in both oil temperature and oil flow velocity, as well with applied electric field. The increase in frequency of the applied electric field reduces the charging tendency of the oil. The material of the rotating disk and oil aging have a pronounced effect on oil electrification.