Optimal Coordination of Over-current Relay Using KHO-KHO Algorithm

The coordination of directional overcurrent relays (DOCRs) is a crucial aspect in ensuring the safety of the power system through the proper alignment of primary and backup protection systems. The goal of the coordination problem of overcurrent relays (OC) is to optimize the sum of the total operating time for all the main relays. The plug settings (PSs) and time dial settings (TDSs) play a crucial role in determining the operating time of relays. The challenge lies in the fact that the optimization model for this problem is non-linear and highly complex. This paper aims to introduce a KHO-KHO optimization (KKO) method, to optimize the coordination of DOCRs. The algorithm proposed in this study has been tested on the lEC microgrid test systems. The results indicate the efficacy of the proposed KKO algorithm in reducing the operating time of relays for optimal coordination of the DOCRs. The results obtained from the KKO algorithm are compared with those from other optimization algorithms. The current approach provides the lowest relay operating time with optimized TDS and PS. The analysis of the results shows that the KKO method is efficient, straightforward, and accurate.