Optimal Protective Coordination of Overcurrent Relays in Electrical Distribution System with the Presence of Distributed Generation

Abstract

In the current scenario, the principle of penetration of electric grid delivery generation technologies is being rigorously applied. With the inclusion of distributed generation sources within the network, the short circuit MVA capacity of the electrical distribution network increases. The variation in short circuit current levels would depend on the network layout, DG sizing, and the DG placement. The discrimination time period associated with the pair of main and backup relays is breached because of the variation in short-circuit current levels. Thus, with the presence of distributed generation, coordination between main and back up relay’s malfunctions. The relay settings should therefore be properly updated in every region of the power system. By choosing the Optimum time dial setting (TDS) and pickup current or plug setting, an optimum setting of Overcurrent Relay coordination (OCR) coordination can be achieved. The Elephant herding algorithm (EHA) is suggested to overcome the optimum overcurrent relay coordination without sacrificing the characteristics. The impact of penetration of various Distributed Generation sources on Over-Current Relays in the 33-test bus distribution system has been observed from the simulation outcome and analysis, and the optimal relay settings as well as the usefulness of the proposed algorithm in locating optimal coordination of over-current relays.