protection and control group, zanjan regional electric company
Directional overcurrent relays (DOCRs) are widely used to protect power systems. For optimal coordination of DOCRs, several techniques have been proposed to solve this problem. A common way of optimal coordination of DOCRs is using evolutionary algorithms such as genetic algorithm (GA). In this paper, a novel strategy for DOCRs coordination is proposed. In the proposed strategy, a new objective function (OF) is introduced. The proposed objective function can removed mis-coordination between paired relays and can result in better coordination. Proposed OF is applied to 6-bus and 30-bus sample networks.