双流制机车变压器合闸到交流电网的冲击电流分析

摘要

双流制电气机车变压器合闸到交流电网瞬间产生的冲击电流与运行于直流电网时铁心中的剩磁有关.机车运行于直流电网时变压器仅作为滤波电抗器接入回路,绕组的连接方式使磁场分布具有漏磁特点,基于此,提出采用"平均"磁化曲线和"局部"磁化曲线来刻画漏磁特性,分别计算两种磁化曲线下的合闸冲击电流,分析该两种磁化曲线对计算结果的影响,并对两种磁化曲线下的合闸冲击电流进行谐波分析.该计算方法可为双流制电力机车主变压器的电磁设计、暂态分析及继电保护提供参考依据.%Inrush current occurred at a locomotive transformer switched to AC power grid is relat-ed with residual magnetic from DC operation status.When the locomotive runs in the DC power grid,the transformer is only used as filter reactor.Because of the winding connection,the mag-netic field distribution has the characteristics of leakage flux.According to the analysis of the leakage magnetic field,an average magnetization curve and a local magnetization curve were pro-posed to reflect leakage magnetic field,and the switching inrush current under different magneti-zation curves were calculated respectively.The influences for calculation results caused by differ-ent magnetization curve were analyzed.Finally,harmonics within switching inrush current under different magnetization curves were conducted.The analysis results provide important theoretical basis for the design of the main transformer of electric locomotive,the design of filter circuit and relay protection.