A new genetic algorithm method for optimal coordination of overcurrent relays in a mixed protection scheme with distance relays

Several optimal coordination of overcurrent relays have been done in the past by using linear programming such as simplex, two-phase simplex and dual simplex and also intelligent optimization techniques such as genetic algorithm (GA) techniques. In this paper, a powerful optimal coordination method based on GA is introduced. The objective function (OF) is developed in a way that in addition to coordination of overcurrent relays, the coordination of overcurrent and distance relays is achieved. In other words, the novelty of the paper is the modification of the existing objective function of GA, by adding a new term to OF to fulfill the coordination of both overcurrent and distance relays. The method is applied to a power network system and from the obtained results it is revealed that the new method is efficient and accurate.