具有故障限流功能的线间直流潮流控制器及其控制方法

针对多端直流输电系统潮流调节和故障电流抑制两大难题,提出一种具有故障限流功能的线间直流潮流控制器(IDCPFC),可以实现线路电流灵活调节和直流故障电流抑制.首先,介绍了IDCPFC的拓扑结构、工作原理和等效电路,该结构具有模块化、可拓展的优势,在此基础上提出了电压、电流分时控制方法.然后,分析了所提IDCPFC在直流短路故障工况下的运行特性,提出了闭锁降压限流方法和过压旁路保护策略,研究了故障电流抑制能力的影响因素及参数选取.最后,在PLECS中建立了三端直流系统的仿真模型,仿真结果证明了所提IDCPFC在潮流控制、功率阶跃和故障限流工况下的有效性,并研制了小型样机验证了IDCPFC的潮流调节和故障限流功能.

Interline DC Power Flow Controller with Fault Current Limiting Function and Its Control Method

In order to solve the problems of power flow regulation and fault current limitation in the multi-terminal DC transmission system, an interline DC power flow controller (IDCPFC) with fault current limiting function is proposed, which can achieve flexible adjustment of line current and DC fault current limitation. Firstly, the topological structure, operation principle and equivalent circuit of the IDCPFC are introduced. The structure has the advantages of modularity and expandability. On this basis, a voltage and current time-sharing control method is proposed. Then the operation characteristics of the proposed IDCPFC under the DC short-circuit fault condition are analyzed, and the blocking method for voltage-reducing and current-limiting and the over-voltage bypass protection strategy are proposed. The influencing factors and parameter selection of the fault current limiting capability are studied. Finally, a simulation model of the three-terminal DC system is established in PLECS. The simulation results show the effectiveness of the proposed IDCPFC in the conditions of power flow control, power step change and fault current limiting. A small prototype is developed to verify the power flow control and fault current limiting functions of the IDCPFC.