柔性中压直流铁路牵引供电系统分布式协调控制策略

Distributed coordinated control strategy for flexible medium voltage direct current railway traction power system

柔性中压直流铁路牵引供电系统可缓解传统工频单相交流25 kV铁路牵引供电系统存在的电能质量问题并取消电分相。针对柔性中压直流铁路牵引供电系统中并联牵引变电所的协调控制问题,提出了一种分布式协调控制策略。该控制策略由两级控制组成,牵引变电所的一级控制通过下垂控制实现负载功率的一次分配。二级控制与相邻牵引变电所进行信息交互,利用有限时间一致性算法,实现各牵引变电所输出电压平均值二次调节。该控制策略在维持牵引网直流电压稳定的同时,实现负载功率的就近分配,减小了系统供电损耗。当某牵引变电所超负荷或故障退出时,可由距其最近的牵引变电所补充出力,避免供电中断事故,提升了牵引供电系统的供电可靠性。进一步地,建立详细的柔性中压直流铁路牵引供电系统仿真模型,模拟真实的机车运行工况,仿真结果验证了所提控制策略的有效性。

Flexible MVDC(Medium Voltage Direct Current)railway TPS(Traction Power System)can relieve the power quality problem of conventional power frequency single-phase AC 25 kV railway TPS and cancel the catenary neutral sections.Aiming at the coordinated control problem of parallel TSS(Traction SubStation)of flexible MVDC railway TPS,a distributed coordinated control strategy is proposed.The control strategy consists of primary control and secondary control,the primary control of TSSs responses the primary distribution of load power by droop control.The secondary control interacts with the adjacent TSSs and employs the finite time consistency algorithm to realize the secondary regulation of the TSSs’average voltage.While maintaining the stability of the DC voltage of the traction network,it realizes the nearby distribution of load power and reduces the system power supply loss.When a TSS overloads or exits operation with a fault,the power can be supplemented by the nearest TSSs,which avoids power interruption accidents to improve power supply reliability of TPS.Furthermore,a comprehensive simulation model of the flexible MVDC railway TPS is conducted to simulate the actual operating conditions of the trains,and the simulative results verify the availability of the proposed control strategy.