Optimal coordination of directional overcurrent relay coordination

Directional overcurrent relays are used to protect interconnected power systems and looped distribution systems. Several techniques and formulations have been proposed to solve the directional overcurrent relay problem. In this paper, the proposed formulations for relay coordination problem are discussed. The protective relay coordination problem is reformulated to take into account the discrete pickup current values. The directional overcurrent relay coordination problem is formulated as a mixed integer-programming problem. The problem is solved using the OSL solver of the general algebraic modeling system (GAMS).