Optimal directional overcurrent relay coordination based on computational intelligence technique: a review

An exponential increase in diverse load demand in the last decade has influenced the integration of more power plants into the power system. This increases the fault current due to the bidirectional flow of current, resulting in unwanted tripping of the relays if not properly coordinated. Therefore, it is imperative to ensure the installation of relays in the grid being able to sense the fault current from any direction (i.e. upstream or downstream). This can be accomplished by introducing an optimal directional overcurrent relay (DOCR) coordination scheme into the system. This paper presents an in-depth review of the applications of various optimization techniques for optimal coordination of directional overcurrent relays (DOCRs) in integrated power networks. The review highlights the advantages and limitations of techniques implemented to mitigate the DOCR coordination issues. Furthermore, potential research directions for optimal DOCR coordination are also discussed in this paper.