基于原牵引变电所的结构和接线,增设断路器和变流器.通过闭合和开断断路器,使牵引网电压相位一致,实现异相供电向同相供电的转换；变流器作为平衡变换装置,当端口接线角相差±90°时,采用背靠背单相变流器,相差±120°时,根据接线形式分别采用三桥三端子或三桥四端子变流器；根据所给出的补偿电流公式,不同的平衡变换装置均可输出期望的补偿电流,解决同相供电方式带来的负序电流叠加问题.仿真结果表明,平衡装置投入后,电力系统三相电流为对称的纯正弦基波波形与高频调制波形的叠加,是与电压同相位的正弦波.%The out-phase power supply is transferred to in-phase power supply by applying additional breakers and converters to original structure and lines of traction substation. The phases of traction voltage become consistent by switching on/off the breakers. The converter is used as balancing device. Single-phase back-to-back converter is applied when the phase difference between two ports is ±90° while three-bridge three-terminal or three-bridge four-terminal converter is applied according to the connection mode when the phase difference is ±120° The expected compensative current is generated by the balancing device according to the given formula to avoid the superposition of negative currents caused by in-phase power supply. Simulative results show that,the three-phase current of power system is the superposition of the sine fundamental wave and the high-frequency modulation wave,which is in-phase with the voltage.
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