Research on Voltage Overlimit Suppression Measures for Weak Traction Networks Based on Energy Storage Type Railway Power Conditioner

In response to the problem of traction network voltage exceeding the limit under weak grid conditions, an energy storage(ES) type modular multilevel converter(MMC)-railway power conditioner(RPC), also known as ES-MMC-RPC, is adopted to suppress network voltage fluctuations and stabilize network voltage. Compared to schemes of the system power supply capacity improvement and reactive power compensation with capacitor banks, it is found through simulation that the strategy of ES-MMC-RPC installed in the section post combining both grid following(GL) and grid forming(GF)/three-degree controls has a better effect on stabilizing the voltage. In addition, it has better economic effect. Finally, a three-layer energy management strategy for the equipment is proposed and verified by simulation, which provides triple support for stabilizing the voltage through active power balance, reactive power support from the equipment itself and the ES device to ensure the voltage stability in weak grid areas.