Saeed Nikbakhsh Jahromi - Department of electrical engineering, Sharif University of Technology, Tehran, Iran
Ehsan Hajipour - Department of Electrical Engineering, Sharif University of Technology, Tehran, Iran
Mehdi Ehsan - Department of Electrical Engineering, Sharif University of Technology, Tehran, Iran

Recent weather-related disasters experienced worldwide with considerable damages to the interconnected power infrastructure have highlighted the importance and urgency of enhancing the resiliency of the distribution grid. A Resilient distribution grid can withstand and recover from such rare events. Resiliency against extreme events is conceptualized in three distinct stages: prior, during, and after the event. Rapid recovery is a feature of after the event stage. In this paper, restoration strategies to restore maximum loads as quickly as possible are investigated. The proposed approach attempts to restore the critical loads by using tie-switches to reconfigure the network. In the case of isolated areas without the possibility of using upstream utility grid, sectionalizing the grid into several microgrids (MGs) is proposed to improve the system resiliency. The number of isolated MGs is an issue that is required to be correctly determined. So, a new approach is proposed to compromise between amount and reliability of supplied load to find the optimum number of MGs. The proposed method is simulated on the unbalanced IEEE-۱۲۳ and ۳۷-bus distribution grid with random locations for DERs.

Resiliency, Reconfiguration, Microgrid, Restoration, Critical load