Considering the series compensation in optimal coordination of directional overcurrent protections using PSO technique

This paper presents an optimal coordination of inverse definite minimum time (IDMT) direction overcurrent relays (DOCR) in electrical networks considering the impact of the line series compensation (SC). The coordination problem is formulated as a non-linear constrained mono-objective optimization problem. The objective function of this optimization problem is the minimization of the total operation time of the associated relays in the power system, and the decision variables are: the time dial setting (TDS) and the pickup current setting (Ip) of each relay. To solve this complex non linear optimization problem, the Particle Swarm Optimization (PSO) is used. The original PSO algorithm is improved in order to handle the inequality constraints violation considering a penalty function. The proposed method is validated on 8-bus power transmission systems test systems considering various scenarios. The obtained results show a high efficiency of the proposed method to solve such complex optimization problem, in such a way the relays coordination is guaranteed for all simulation scenarios with minimum total operating time.