Optimal Coordination of Directional Overcurrent Relays Using Bacteria Foraging Algorithm

Optimal setting in relay coordination of Directional overcurrent relay (DOCR) is a major challenge for protection engineers. This paper throws light on the application of Bacteria Foraging Algorithm (BFA) in solving problems related to coordination of directional overcurrent relays. The Time Dial Setting (TDS) and pick up current setting or plug setting (I-p) act as decision variables of each relay. The objective function for optimal coordination of the relays is to minimize the summation of operating times of all the primary relays, responding to clear the faults of their corresponding zones. In this study three models are considered namely IEEE 3-bus model, IEEE 4-bus model and IEEE 6-bus model. The results show that the proposed algorithm is competent and efficient to solve such non-linear problems.