Study on dynamics of the bubble in transformer oil under non-uniform electric field

This study explores the dynamics of gas bubbles in liquid dielectric theoretically and experimentally. A numerical model is introduced for the bubble motion in the transformer oil under non-uniform electric field. Moreover, the bubble trajectory is obtained through the force calculation of the bubble under the non-uniform electric field. The numerical calculations for different bubble sizes and applied voltages are also done. Notably, trajectories calculated indicate the bubble aggregation in concentrated area of the electric field between the needle-plane electrodes. It is concluded that the bubble can play a catalytic role in the breakdown of the oil gap. An experiment is finally conducted on the bubble motion in transformer oil gap submitted to a high divergent electric field and the suspension and aggregation of bubbles are observed before the oil gap breakdown, which confirms the results of numerical calculation.