新型24kV柔性直流铁路牵引供电系统分层控制策略研究

A Hierarchical Control Strategy for the Novel 24kV Flexible Direct Current Railway Traction Power System

相比于传统25kV工频单相交流牵引供电系统,24kV直流铁路牵引供电系统在电能质量治理、增加供电距离、易于可再生能源接入等方面更具优越性。针对24kV直流铁路牵引供电系统中多个并联运行牵引变电所的协调控制问题,该文提出一种基于离散时间动态一致性算法的分层控制策略。该方法通过一层控制和二层控制实现各直流牵引变电所根据其额定容量按比例分担所有负荷功率,同时调节各个牵引变电所的输出电压使其均值稳定在系统额定电压。进而,从状态空间建模和稳定性分析方面,分析了牵引负荷移动情况下所提控制策略的有效性。最后搭建系统仿真模型,仿真结果表明提出的分层控制策略在负荷移动、突变、牵引变电所故障、机车再生制动情况下均可以保证各牵引变电所输出稳定直流电压,并且根据其额定容量按比例分担牵引负荷功率。

The 24 kV direct current(DC)railway traction power system is an alternative mode to the conventional 25 kV single-phase AC railway traction power system in terms of the power quality improvement,extending power supply distance,and the easy integration of renewable energies.In order to address the problem of the coordinated control among the multiple parallel-connected traction substations(TSSs)in the 24 kV DC railway traction power system,this paper proposed a hierarchical control strategy based on the dynamic consensus algorithm.Through the primary control and secondary control,the traction load power was proportionally shared among the TSSs according to its rated capacity,and the average value of the output voltage of all TSSs was stabilized at the rated voltage of the system simultaneously.Furthermore,the state space model of the system with proposed hierarchical control strategy was established to analyze the stability of the system under load movement.Finally,the simulation results demonstrated that the proposed hierarchical control strategy could achieve stable output voltage of each TSS and traction load power could be proportionally shared among the TSSs under the condition of load movement,sudden change,any fault of a TSS,and when trains were in regenerative braking status.