纳秒脉冲电压下变压器油流注放电特性分析

Streamer discharge characteristics in transformer oil with nanosecond impulse voltage

为了研究纳秒脉冲电压下液体介质放电过程中带电粒子的微观动力学行为,以场致电离机理作为理论基础,仿真研究了纳秒脉冲电压下变压器油中流注放电过程,分析了流注放电随时间发展的过程,同时考察了外施电压幅值及脉冲上升时间对放电过程的影响。仿真结果表明:0.1/2μs的纳秒脉冲电压下,流注传播时空间电荷对流注的发展起决定性作用,空间电荷区域能够增强流注头部电场,促进流注不断向前发展;随着外施电压幅值升高,流注的传播速度加快,对应的电场峰值、空间电荷密度和温度增长速率加快;脉冲电压上升沿的时间越短,流注的半径越大,对应的最大电场强度越小。

Based on the field ionization mechanism, the streamer discharge process in transformer oil is simulated to study the microscopic dynamics of charged particles during liquid dielectric discharge process with nanosecond pulse voltage. Then the development of streamer discharge versus the time is analyzed. The effect of external applied voltage amplitude and pulse rise time on discharge process is investigated. The simulating results show that the space charge region can strengthen the electric field of streamer head to promote the continuous development of streamer, which plays a decisive role in the development of streamer during the streamer propagation with 0.1/2 μs nanosecond pulse voltage. And with the applied voltage amplitude increasing, the streamer propagation will speed up, as well as the rising rates of corresponding electric field peak, space charge density and temperature. Besides, the shorter pulse voltage rise time and the larger streamer radius will cause the smaller value of the maximum electric field strength.