Study on the mechanism of static electrification in transformer oil

We have studied the influence of various impurities produced due to thermal aging in transformer oil and ionic surfactants on static electrification. A model for producing static electrification is proposed. The static electrification measurement was carried out in a system with a rotating disk. The impurities, such as ROH, RCOOH, ROR, R-C=O etc., and negative ionic surfactant make the positive static electrification increase. However, electrostatic charging charges in transformer oil become negative after thermal aging at 110/spl deg/C about 12 hours. The experimental results show that positive ionic surfactant can produce negative charges in transformer oil. It is proposed that in aging transformer oil the impurities to be similar to positive ionic surfactant may be formed.