Application of Firefly Algorithm for Optimal Directional Overcurrent Relays Coordination in the Presence of IFCL

This paper considers the impact of the Inductive Fault Current Limiter (IFCL) on d irect ional overcurrent relays coordination.The coordination problem is formulated as a non-linear constrained mono-objective optimization problem.The objective function of this optimizat ion problem is the minimizat ion of the operation time of the associated relays in the systems, and the decision variab les are: the time dial setting (TDS) and the pickup current setting (I P ) of each relay.To solve this co mplex non linear optimization problem, a variant of optimization algorith ms named Firefly A lgorith m (FA) is used.The proposed method is tested on 8-bus power transmission systems test systems considering the influences of current relay under three-phases short-circuit with and without IFCL for d ifferent locality.The results show the effectiveness of the solution.