Planning the coordination of directional overcurrent relays for distribution systems considering DG

Introduction of distributed generation (DG) to the power system may lead to nonselective protection actions. For every future DG installation, the relay settings need to be modified to guarantee protection coordination that can lead to numerous changes in relay settings. This paper presents a novel approach to plan relay protection coordination considering future DG installations. Thus, this paper aims at proposing a method capable of optimally identifying one set of relay settings valid for all possible future DG planning scenarios. The proposed algorithm is formulated as a linear programming problem and the simplex algorithm is utilized to solve it. The proposed approach is tested on the distribution part of the modified meshed IEEE 14-bus system and the IEEE 13-bus radial test system. Comparative studies have been conducted to highlight the advantages of the proposed approach under various planning scenarios considering application of fault current limiters.