基于图论的配电网孤岛连通性判别

当配电网主干线发生故障，需要将配网与大电网断开，然后对配电网进行网络重构。要使得重构后的配电网能够稳定运行，需要对重构后的孤岛系统进行连通性判别。传统的判别方法仅考虑了传统的备用电源，并没有考虑大量的分布式电源。大量分布式电源(DG)接入配电网后，若配电网重构，使得配电网的网络结构更加复杂。采用改进的广度优先搜索算法对配网的连通块进行电气连通性判别，并采用含分布式电源的19节点系统进行算例分析。结果表明，考虑DG接入的电气连通性判断算法不但能搜索出含DG的配电网的多个连通块，还能准确判别各个连通块的电气连通性。

Research on the Connectivity of Distribution Network Island Based on Graph Theory

A large number of distributed generation(DG) has accessed to the distribution network which makes the structure of the distribution network complicated. When a fault occurs on a trunk line in distribution network, it is needed to disconnect the faulty part of distribution networks from the grid, and reconfigure the distribution networks. The utilization of DG to recover the part load supply can improve both the reliability of distribution network and the utilization rate of the distributed power supply. In order to maintenance the stable operation of the reconfigured network, it is needed to distinguish the connectivity of islanding system after the reconfiguration. The conventional discriminant method only considers the traditional standby power but ignore the large number of distributed generators. In this paper, the improved breadth-first search algorithm is used to distinguish the connectivity blocks of the distribution network, and a 19-node system with distributed generation is adopted in the case study. The results show that the proposed algorithm can not only search the multiple connected blocks of the distribution network containing DG, but also can accurately distinguish the electrical connectivity of each connected block.