Impact of metal particle size on partial discharge characteristics of moving metal particles in transformer oil

Metal particle contamination in transformer oil can cause PD. When the size of metal particles changes, it seriously affects all kinds of forces acting on metal particles. The variation of these forces will further affect the trajectory, distribution, and PD of metal particles. This study analyzes PDIV, PRPD Diagram, and Statistical Characteristic Parameters under the condition of different particle sizes. The impact of particle size on the characteristic parameters of PD is examined. The trajectories are simulated in an oil duct when the particle size varies. As the metal particle size increases, the initial discharge voltage decreases, the number and amplitude of discharge increases, the time interval between adjacent discharges shortens, the equivalent cumulative discharge increases, and the signal entropy becomes more complex, which makes PD more intense. Overall, a rise in particle size increases PD possibly because of particle oscillation within the system.