微电网线路保护方案优化研究

针对微电网在并网和孤岛运行状态下,故障电流差距较大,使得保护识别故障和上下级线路保护之间的选择性配合较为困难。文中考虑传统保护整定配合困难及无法同时满足两种运行模式下的上下级线路选择性或速动性要求,提出了保护采用正序电流识别故障方向和过电流辅助保护的启动条件。其次提出基于通信系统实现线路上下级保护的自适应整定延时和阶梯形的后备延时作为选择性方案。文中通过MATLAB/Simulink环境中构建了典型的辐射型微电网算例,通过典型工况验证了该方案的有效性。

Research on Optimization of Microgrid Line Protection Scheme

As the micro-grid operating in the grid and island conditions, the fault current gap is large, which making it difficult to identify and realize a better coordination between the upper and lower lines. In this paper, it is necessary to consider the requirements of the traditional protection setting and the difficulty of setting the upper and lower line tripping time of the microgrid in the two modes of operation. In this way, it is proposed to use the positive sequence current to identify the fault current direction and adopt the overcurrent coordination protection condition under the grid and island state protection. Secondly, this paper proposes an adaptive tuning delay and stepped backup delay based on the communication system to realize the upper and lower protection of the line as the selective scheme. For the more micro-radiation micro-network, the communication system to the public connection point for the most advanced, each line level in turn decline, which subordinate delay signal to the higher level transmission. In the MATLAB / Simulink environment, a typical example of radiation microgrid is constructed, and the effectiveness of the comprehensive protection scheme is verified by typical working conditions.