Directional Overcurrent Relay Coordination Using Hybrid BBO-PSO Technique

Abstract

Directional Overcurrent Relays (DOCRs) coordination problem is expressed as a nonlinear optimization problem with many constraints. The aim of this optimization problem is to minimize total operating time of primary relays, which depends upon independent variables: plug setting (PS) and time multiplier setting (TMS). The developed optimization problem is exposed to numerous constraints which are mainly dealing with the coordination time interval of the primary and backup relay pair, as well as bounded value of TMS, PS and the operating time of each relay. The number of relay setting increases with the expansion of the power system network, then the optimization problem becomes very complicated and not easy to solve. In this paper optimization problem has been solved using a hybrid BBO-PSO, merge with Biogeography-Based Optimization Algorithm (BBO) and Particle Swarm Optimization (PSO). This hybridization is done to enhance the performance of both techniques. 8-bus system model is considered as test system to check the effectiveness of the proposed algorithm.