Effect of different shapes of electrodes on bridging in contaminated transformer oil

Contaminated transformer oil has been tested under non uniform electric fields and the effect of different electrode systems presented in this paper. Three different electric fields were examined i.e. DC, AC and DC biased AC. These experiments revealed that with all the different electrodes arrangements, contaminated particles were always formed bridges between electrodes under DC electric field. AC field does not induce any bridging. Combination of AC and DC enhances the bridging dynamics. The bridges were thicker or more particles attracted with more uniform electric field (spherical electrode) than diverse electric field (needle-plane).