Comparative analysis of directional overcurrent relay coordination using linear and nonlinear protection schemes

In this paper, the relay coordination problem is formulated as a linear and non-linear optimization problem with a number of operational constraints. The primary objective of DOCR coordination is to identify the optimal relay settings to achieve the least overall operation time of all relays without any relay pair miscoordination. Also, a comparative analysis of relay coordination has been performed using standard and user-defined relay characteristics. In this study, the application of grey wolf optimization (GWO) for the optimal coordination of DOCRs in a mesh power system is discussed. Additionally, in terms of optimization algorithm, the obtained results are also compared with a genetic algorithm (GA). The performance of the proposed algorithm is tested on the distribution part of a modified IEEE-14 bus test system.