A Novel Protection Coordination Scheme for Regionalized Microgrid at Islanded Mode

The modern microgrids are becoming very complex due to the growing penetration levels of renewable distributed generations (RDGs). The integration of RDGs in power system can lead to change in the fault current level and network topologies, which in turn cause the overcurrent and relay coordination issues. Design and selection of a proper protection scheme is very important for reliable and safe operation of microgrid. In this paper, the effect of different penetration levels of renewable DGs and loads has been considered for an adaptive protection coordination scheme of regionalized microgrid. The main focus of this paper is on use of optimization algorithm to obtain maximum current along each line. Based on these values, proper pick-up current setting can be determined for each over-current protection. Case studies have been performed with the different ranges of penetration level of RDGs and load demands. Results have shown the strength of proposed algorithm. This analysis can be very helpful to maintain the reliability and security of the grids with high penetration level of renewable generation.