Simulation of Bubble Deformation in Flowing Transformer Oil

The bubble deformation in flowing oil is different from that in static state, which can change the distribution of electric field and then affects partial discharge (PD) intensity. However, research on bubble deformation in flowing oil is seldom studied. Therefore, a finite element method is used to determine the bubble deformation. The effect of bubble shapes on electric field is simulated, and the comparison of bubble deformation between flowing oil and stationary oil are also performed. Besides, PD experiments are performed in both two states to verify the simulation results. The simulations show that the bubble deformation determines the electric field distribution. The electric field distortion in horizontal elliptical bubbles is larger than that in vertical elliptical bubbles. In return, the electric field can also elongate bubbles in the direction of electric field. In stationary oil, the steady shape of bubble is a horizontal ellipsoid with serious stretching, which cause significant electric field distortion. In flowing oil, the Flow field and electric field can weaken the horizontal elongation of bubbles, leading to the decline of the electric field distortion compared with that in stationary oil. PD experiments induced by bubbles in both stationary and flowing states are performed on an experiment platform, and the experiment measurements are consistent with the simulation results.