Optimal coordination of directional overcurrent protection relays using genetic algorithm

This paper studies on establishing the mathematical optimization formulation to coordinate the operating times of directional overcurrent relays in transmission networks. The objective function of this optimization formulation is to minimize the total operation time of all directional overcurrent relays, and it must satisfy the highly nonlinear constraints such as the time multiplier setting range, the plug setting range, and the coordination time interval between the primary and backup relay pair.