Alternative coordination approaches for implementation in Smart Grid

As Smart Grid concept is employed in the electric power system, network load flow and topologyis changingintensively to meet the best generation-demand balancing point. These changes must be accounted for the protection devices in order to enhance their performance. The coordination of directional overcurrent relays is most commonly studied based on fixed network operation and topology within a mesh power system. But the sub-transmission and distribution systems constantly operate differently in order to satisfy the variety of load demand levels throughout the day and year. Hence, if the setting of directional overcurrent relays (DOCRs) change according to the different operations of the system, then relay operation time and sensitivity can both be enhanced. This can potentially improve the protection performance in Smart Grid system. Therefore, the study is carried out based on the comparison among three coordination approaches: conventional (fixed settings), discrete (changing setting groups), and continuous or real time (dynamic settings).