中文摘要：

由于现有电气化铁道牵引负荷的不对称性,导致电力系统含有大量负序电流,牵引变压器运行效率不高。为了解决上述问题,对星形-双梯形接线三相变两相平衡变压器进行了研究,重点分析其负序特性及效率特性,并在不同负载工况下,探讨一次侧电流不平衡度及变压器运行效率的情况,得出了电流不平衡度为零且变压器运行效率最高的条件。通过MATLAB建模对其负序特性与效率特性进行了仿真研究,结果表明该变压器能抑制负序电流的产生。

英文摘要：

The unbalanced load of electrified railway causes big negative sequence currents,resulting in low efficiency of traction transformer. The three-phase to two-phase balance transformer connected in Y and double trapezoids is researched and its characteristics of negative-sequence and efficiency are analyzed. The unbalance degree of the current at primary side and the operating efficiency of transformer are studied under different loads ,and the conditions to achieve zero current unbalance degree with highest transformer efficiency are obtained. Simulative study is carried out with MATLAB and results show that the transformer suppresses the negative sequence current effectively.