Characterization of discharge associated with fiber particle aggregation in oil streams under high voltage direct current field

Compared to stationary insulation oil, the agglomeration characteristics of fiber particles and their accompanying partial discharge characteristics in flowing insulation oil are more complex. In order to investigate the effects of voltage amplitude, agglomeration level, and oil flow velocity on the agglomeration characteristics of fiber particles and their accompanying partial discharge characteristics, an experimental platform for high-voltage direct current discharge detection under oil flow conditions was established in this study. The research findings are as follows: when the oil flow velocity and voltage amplitude are constant, with the increase of continuous pressurization time, the partial discharge quantity accompanying the agglomeration of fiber particles between the electrodes will rapidly increase when the fiber particles aggregate to form a through "impurity small bridge". The impact of voltage amplitude on the agglomeration of fiber particles and the characteristics of their associated discharges is more significant than that of oil flow velocity and agglomeration level. In a high-voltage direct current (HVDC) uniform electric field. It’s observed that the UHF signals detected are characterized as half-wave signals. As the velocity of the oil flow increases, there’s a noticeable reduction in the discharge quantity of agglomerated fiber particles, and the effectiveness of flow velocity in mitigating partial discharges starts to wane. At an oil flow velocity of 0.2 m/s and a voltage level of 16 kV, fiber particles show minimal agglomeration between electrodes. At the same duration of continuous pressurization, the degree of aggregation of fiber impurity particles between the electrodes gradually increases with the rise in voltage amplitude.