市域铁路双边供电系统的稳态潮流

Steady-State Power Flow in Bilateral Power Supply System for Suburban Railways

针对市域铁路列车不中断供电的要求,对市域铁路采用双边供电技术取消电分相进行分析研究.根据不同的外部电源供电方式建立平行双边供电和树形双边供电的等值电路模型,推导均衡电流的计算模型,分析减小均衡电流的措施;并以某市域线路为例,仿真计算系统不同运行方式下的潮流分布和均衡电流,验证均衡电流计算模型的正确性以及市域铁路单相交流牵引供电采用双边供电方式的可行性.研究结果表明:实例中的市域线路合环时,牵引变压器最大功率为70.36 MV·A,最大电压波动为0.702 5%,110 kV输电线路承受的最大电流为833.418 A,双边供电系统中“电磁环网”对电网潮流分布的影响均在牵引变压器、输电线路承受范围内,稳态情况下满足电力系统要求;合环线路中均衡电流占比为2.322%,对系统的影响较小.

As suburban railways necessitate uninterrupted power supply,bilateral power supply technology is explored to apply in canceling electric phase separation.The equivalent circuit models of parallel bilateral power supply and tree bilateral power supply are established in different modes of external power supply.The calculation model of equilibrium currents is deduced,and the measures are analyzed to reduce equilibrium currents.Taking a city line as an example,the power flow distribution and equilibrium current are simulated under different system operation modes,and the calculation model of equilibrium currents is verified.The feasibility analysis is conducted as to using the bilateral power supply modes in the single-phase AC traction for suburban railways.The results show that in this case when the municipal lines are closed,the maximum power of the traction transformer is 70.36 MV·A,the maximum voltage fluctuation 0.702 5%,and the maximum current in110 kV transmission line 833.418 A.In the bilateral power supply system,the traction transformer and the transmission line can endure the influence of the electromagnetic loop network on the power flow distribution of the grid,which meets the power system requirements in the steady state.The proportion of the equilibrium current in loop closing lines is 2.322%,which has small influence on the system.