Discharge characteristics and mechanism of conductive metal particles in function of the oil flow under AC voltages

To obtain the characteristics and mechanism of partial discharge caused by metal particles in function of the oil flow under AC voltages, the author established a mechanical model of metal particles motion in dielectric liquid. The motion trajectory and distribution regularities of metal particles in flowing transformer oil were simulated and calculated. The discharge phenomenon caused by metal particles was explained based on 4 discharge types and discharge mechanism was investigated. Additionally, Experiments were carried out to research the variation of Partial discharge inception voltage (PDIV) with velocity and temperature caused by metal particles. It was observed that discharge amplitude increased within a little scale and discharge number decreased significantly with the increase of velocity. Rise time increased with the increase of velocity while duration time decreased. It was proved that insulating property of transformer oil which was contaminated with metal particles could be improved by increasing the velocity of transformer oil.