Optimal coordination of IDMT directional overcurrent relays in the presence of series compensation using Differential Evolution algorithm

This research paper presents an optimal coordination of direction overcurrent relays (DOCR) in power systems. The new idea in this paper is to consider the impact of the line series compensation on the DOCR setting and coordination. The coordination problem is formulated as a nonlinear constrained mono-objective optimization problem. The objective function of this optimization problem is the minimization of the operation time of the associated relays in the systems, 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, a variant of evolutionary optimization techniques named Differential Evolution (DE) is used. The original DE algorithm is improved in order to handle the constraints violation considering a penalty function. The proposed method is validated on 6-bus power distribution system and 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 operating time.