基于本地信息的有限选择性直流微电网保护方案

为兼顾直流保护的经济性和选择性，提出一种面向双端直流微电网的有限选择性直流保护方案。首先划分保护区域，分析直流短路故障下的突变电流方向和变化率特征。继而利用区域出口线路的电流突变量信息和有限数目直流断路器的延时配合，形成二级级差式保护方案。待故障电流降至为零，分布式电源有序重启，基于本地电流或电压信息完成“握手式”的健全区域供电恢复。Pscad仿真结果表明，所提保护方案能够摆脱对远程通信的依赖，实现对故障区域的快速辨识和有效隔离。

Protection Scheme with Limited Selectivity for DC Microgrid Based on Local Measurements

To balance the economy and selectivity of DC protection， the paper proposes a DC protection scheme with limited selectivity for dual-terminal DC microgrid. Firstly，the protection area is partitioned， and the direction and change rate of the fault current component under a DC short-circuit fault is analyzed. Then a two-level differential protection scheme is formed by using the fault current components of the power lines connected to the protected area and the time delays of a limited number of DC circuit breakers. When the fault current drops to zero， the distributed generators restart in order. Based on the local current or voltage measurements，the power supply of the sound area is restored in a handshake way. The simulation results of PSCAD show that the proposed protection scheme is independent of the remote communication and can realize the fast identification and effective isolation of the fault area.