Simulation Study of Motion Characteristics of Fiber Impurity Particles Under Oil Flow and Dielectric Barrier

To investigate the charged motion of fiber impurity particles in transformers, a multiphysical field model for the solid-liquid two-phase flow of individual fiber impurity particles in flowing insulating oil was constructed. The charged motion characteristics of fiber impurity particles were analyzed under different oil flow velocities, types of electric fields, and insulation medium thickness conditions. The research conclusions are as follows: oil flow velocity has a significant impact on the motion characteristics of fiber impurity particles. Increasing the oil flow velocity can reduce the number of collisions between fiber impurity particles and electrodes, effectively lowering the probability of charge transfer between them and reducing the likelihood of bridging aggregation. In a uniform alternating electric field, it is challenging for fiber impurity particles to collide with electrodes and transfer charges between electrodes. In a combined ac–dc electric field, with the increase in the proportion of the dc component, collisions and charge transfer between fiber impurity particles and electrodes become more pronounced. The maximum charge carried by fiber impurity particles gradually decreases with the increase of insulation medium thickness, leading to a reduced probability of charge transfer for fiber impurity particles.