中文摘要：

牵引负荷是电力网电压不平衡的主要原因，为治理电气化铁路负序问题，首先给出牵引负荷产生的负序电流的通用计算方法，并结合牵引变电所实测负荷数据，以某电力系统为例，通过编程、仿真分析了牵引负荷引起的电压不平衡度在电网中的分布规律。结果表明：1）从单个牵引变电所来看，阻抗匹配平衡变压器具有非常好的降低负序的效果；2）牵引负荷对高电压等级节点的电压不平衡度的影响很小；3）电压不平衡度随节点距牵引变电所的距离的增大而减小。

英文摘要：

Traction load is the main reason for the unbalanced voltage of electric power networks.The general calculation method for negative sequence current of traction load is given, and the distribution law of voltage unbalance in power system is analyzed by means of the load data.The results show that： 1） from a single traction substation, the impedance matching balance transformer has a very good effect of reducing the negative sequence, 2） traction load on the voltage level of high voltage, the impact is very small; 3） the voltage unbalance degree decreases with the increase in the distance between the nodes.