Optimum Overcurrent Relay Coordination for Radial Distribution Networks Using Improved Mathematical Formulation

Protective relays are critical components in the protection of a power system. One of the fundamental principles of protective relaying is primary relay should operate first and if it fails to operate then the backup relay should clear the fault. Such type of coordination between primary and backup relays makes protection a crucial or complex task. In this paper, using an improved mathematical formulation of relay coordination, the complexity is reduced. The reduced complexity and avoiding miscoordination is an outcome of employing a new objective function with an additional constraint. Further, it is compared with the conventional approach considering all parameters of radial distribution as it is. Obtained results show that the proposed approach is superior, optimal, and effective as compared to the conventional approach. The performance and effectiveness of the proposed approach are evaluated on two radial distribution networks.