全功率双向变电站与地铁杂散电流问题

地铁杂散电流会腐蚀地铁当中的金属(如承重墙里面的钢筋)，为系统安全埋下隐患。与混合型变电站(由二极管整流器和 PWM 变流器组合而成)相比，由 PWM 变流器构成的全功率双向变电站不但具备正常的能馈功能，而且可基于其良好的调节直流电压的能力来维持各变电站输出电压一致，从而达到降低杂散电流的目的。分析全功率双向变电站降低地铁杂散电流的原理及其改善效果，仿真结果表明，全功率双向变电站能使地铁当中的杂散电流吸收垫充分发挥作用，显著降低地铁杂散电流。

Full-Power Bidirectional Substation and the Problem of Subway Stray Current

Metro stray current can corrode the metal in the subway (for example, the steel bar in the load-bearing wall), which are hidden dangers for the safety of the system. M Compared with hybrid substations (composed of a diode rectifier and PWM (pulse width modulation) converter), full-power bidirectional substations composed of a PWM converter can feed regenerative braking energy back to the power grid. It also has good ability to adjust DC voltage, so it can reduce stray current by maintaining the same output voltage of each substation, as illustrated by the example of the Tsukuba Express Line in Japan, where using a full-power bidirectional substation reduced stray current significantly. This study analyses the principles and effects of the full-power bidirectional substation in improving the stray current problem in metro systems. The simulation results show that the application of a full-power bidirectional substation can make the stray current absorber pad play a full role, and significantly reduce the stray current in the metro system.