Bridging phenomenon in contaminated transformer oil

The effect of cellulose particles contamination on transformer oil has been investigated. Different sizes and concentration levels of cellulose fibres were used to contaminate the transformer oil for the experiments. The conduction current was measured using electrodes of 10 mm diameter with a 10 mm gap and the optical microscopic images of bridge creation between the electrodes were also recorded. The bridge was thickened with increasing concentration level and the bridging time was shortened as the voltage increased. The conduction current increased with concentration level and voltage. Smaller size particles had stronger bond while creating the bridge and higher conduction current.