Cellulose particle dynamics simulation in transformer oil under non-uniform electric field

Abstract

The transformer oil and impregnated paper are widely used as the electrical insulation for electric power apparatus designs. The high contamination level of cellulose particle in the transformer oil can reduce the dielectric strength of the oil paper insulation in transformers and may generate partial discharge or even breakdown with particle accumulation. The motion of the cellulose particle in dielectric liquid is under the influence of electrohydrodynamic (EHD) which concerned with the interaction of dielectric fluids and the electric field. The dynamics of the cellulose particle in transformer oil under nonuniform electric field is theoretically explored in this paper. A numerical model is introduced for the cellulose particle dynamics in the transformer oil under non-uniform electric field. The electrodynamics force is calculated by integrating the Maxwell stress tensor on the surface of the particle, and then the particle velocity and trajectory are obtained through the force calculation of the particle under the non-uniform electric field. Notably, trajectories calculated indicate the particle aggregation in concentrated area of the electric field between the needle-plane electrode, and different particle radius will affect the trajectory of the particle. Also, different electric field strength causes the change in the velocity of particle between the electrodes. It is concluded that the cellulose particle can play a catalytic role in the breakdown of the oil gap.