Optimal Islanding for Restoration of Power Distribution Systems Using Prim's MST Algorithm

Power systems can suffer outages, causing complete or partial disconnection of their power supply to load centers within the distribution networks. Distributed Generation (DG) plays an essential role in power systems. DG can be used as a back-up power source to enhance the resiliency and reliability of a power system. Island mode operations after outages in an active distributing network (ADN) is an effective way to maintain continuity of the power supply to significant loads. It is a quite complicated task for power system operators to find the power flow path. Previous studies have primarily used pre-defined guidelines to find feasible power flow paths, and have focused on multiple islands for restoration. In these studies, possible restoration pathfinding with DG was the fundamental weakness, and furthermore, the power of DG was limited to pre-defined boundaries in the form of islands. Therefore, in this study, a new algorithm has been proposed, which uses the minimum spanning tree (MST) method to find the most feasible path. The proposed algorithm starts at any random node (in this case, DG), and progresses by selecting the next node with the least cost (weight), thus considering all the nodes through which power will flow. The proposed model is formulated as a multi-objective program considering the priority of loads and minimum power loss. The effectiveness of the proposed model is tested on a modified IEEE69-bus distribution system with the penetration of multiple distributed generation sources at different nodes. Results were compared with the strategies found in literature, and the proposed method was found to be feasible and efficient.