Island partitioning of smart distribution systems in emergency situations considering voltage and frequency stability

Abstract

Island partitioning is a solution to restore service in smart distribution systems after the disconnection of the main grid due to faults. A two-stage and multi-objective solution is presented to restore the services of the island system. At first stage, the proposed partitioning scheme is presented with regards to the available time to decide on control measures, considering the voltage stability and the priority and controllability of the loads in the load shedding, and considering the frequency response and the voltage stability margin in finding the borders of the partitions. In the second stage, optimal power flow is done to set the partitions and satisfy the system operational constraints. The results show the proposed method not only leads to the creation of partitions with the allowable bus voltage and frequency but also leads to the lowest losses, the largest amount of restored load, and supplying loads with the highest values. Moreover, proposed method is more comprehensive due to considering voltage stability, frequency stability, occurrence of simultaneous faults, existence of controllable and uncontrollable distributed generation, power reserve, controllability of loads and DGs, position of switches, maximum time available to make decisions about control measures and the time delay between control measures