Numerical simulations of bridging phenomena in contaminated transformer oil

Experiments were carried out on transformer oil contaminated by cellulose fibre. After the high voltage was applied to the electrodes, the pressboard particles accumulated in the highest electric field region and eventually formed a bridge. We have developed a mathematical model to simulate the bridging dynamics. The dielectrophoretic and drag forces are considered for simulation of the particles motion and accumulation. The predicted bridge formation rate and the conduction current between the electrodes showed similar trend to the experimental results. The model is a successful means of predicting bridge formation phenomenon compared with the experimental data.