Distribution Network Fault Recovery Strategy Considering Hierarchical Division and Convergence of Islands

Considering the severe consequences after multi-point faults in distribution grids caused by frequent occurrence of extreme disasters, Utilizing the advantages of closed-loop design of distribution networks, a fault recovery strategy for distribution networks considering islanding hierarchical division and fusion is proposed. Firstly, we consider the influence of contact switches in the traditional islanding model and propose an islanding hierarchical classification method, which is solved by using a breadth-first algorithm and a hybrid particle swarm algorithm to obtain an islanding scheme; secondly, we establish an islanding fusion model, and the islanding fusion model is transformed into a mixed-integer second-order conic planning model by means of a relaxation of nonlinear constraints, and then solved; finally, the proposed method is validated through the simulation of the improved PG&E69 node distribution system. Finally, the effectiveness of the proposed method is verified by the improved PG&E69 node distribution system simulation. Finally, the effectiveness of the proposed method is verified through simulation of the improved PG&E69 distribution system. The case study shows that the proposed distribution network fault restoration strategy can increase the amount of important loads to be restored and expand the scope of load restoration.