基于LCL故障电流控制器的故障快速检测

相较于交流配电网,直流配电网存在故障电流限流、阻断和电能质量治理等多种问题。为减少直流系统中设备的数量,文中提出了一种基于LCL型多功能故障电流控制器拓扑结构,使其同时具备故障限流、故障阻断和电压调节功能。首先针对该拓扑结构,研究其在限流、阻断和电压调节等不同工作目标下的运行工作原理,分析LCL结构的滤波和限流复用过程,提出故障电流的快速检测方法。然后,通过对限流器件不同位置电压变化率和电流变化率的阈值匹配,实现双极故障、单极故障和高阻故障等多类型故障的快速判断。最后,搭建系统仿真模型,验证了该故障电流控制器拓扑同时具备调压、限流和阻断等功能,且能够快速检测故障电流。

Fault detection method based on LCL fault current controller

Compared with AC distribution network, many problems should be solved in DC distribution network, such as fault current limiting, fault current blocking and power quality control. In order to reduce the number of equipment in DC system, a multi-functional fault current controller topology based on LCL structure is proposed, which has the capacity for fault current limiting, fault current blocking and voltage regulation. On account of the topology structure, the operation principle of LCL structure under different working objectives is studied, and the multiplexing process of filtering and limiting current of LCL structure is clarified. A fast detection method of fault current is also proposed. By matching the threshold value of voltage change rate and current change rate at different positions of current limiting device, the fast judgment of bipolar fault, single pole fault and high resistance fault are realized. Finally, the system simulation model is built to verify the validity of multi-functional of the fault current controller topology, and the rapidity of fault current detection.