Coordination of directional overcurrent relay using evolutionary algorithm and linear programming

In this article, we present a new method to coordinate the directional overcurrent relay (DOCR) installed in a meshed electricity network. Using evolutionary algorithms and linear programming we solve the problem that allows the calculation of the adjustment intensity (relay setting current, J) and the time multiplier factor, K, such that, in the light of any triphasic or biphasic failure that may occur in the network, the relays may act in the least time possible and in a coordinated manner. We are considering the problem without taking into account the intensity variations that occur when a switch is opened. It may happen that the problem at hand does not have a solution, in that case we determine the constraints that should be removed in order to achieve at least a partial coordination of the relays.