Accumulation characteristics of free metallic particles in flowing transformer oil under uniform and non-uniform electric field

Abstract

Transformer oil is easily polluted by metal particles. Once the metal particles accumulate in the oil channel, the insulation performance of the equipment will be greatly reduced. In this paper, an oil circulation device was built and the accumulation characteristics of free metal particles in flowing transformer oil were carried out under uniform and non-uniform electric field. The images of particle accumulation process were captured by a high-speed camera. Simultaneously, we analysed the force conditions of particles in oil. And the accumulation mechanisms under different electric fields were discussed combined with the particle trajectories. It was reported that particle accumulation could be observed in static oil under both electric fields. The particle concentration between electrodes decreased gradually with time. However, when the transformer oil was flowing, the accumulation concentration of particles decreased significantly with the increase of flow velocity. The accumulation of metal particles was seriously damaged, even no longer occurred.