AbstractThis paper presents an overview on optimal overcurrent relay coordination in protection system and protective relays. Efforts have been made to include all methods used for the coordination of overcurrent relays. It includes techniques, such as Artificial Intelligence (AI) and Nature Inspire Algorithm (NIA) as well as other conventional methods used for overcurrent protection. A brief mentioned is made about conventional methods while more prominence is given on the application of AI and NIA for the protection of overcurrent relays. This paper presents a set of references of all respective papers related and provides a brief summary of the research work. In addition, the results of these techniques also provided in the respective references.