Optimal relay coordination in transmission and distribution system: a critical review

This paper presents a state of art review of optimal relay coordination in transmission and distribution system. In power system properly coordinated scheme is designed to ensure that the only faulted zone of system will be disconnected when system faces abnormality. As the power system is complex and demand is continuously increasing, the utilities must improve the reliability using properly coordination techniques for relays. Many researchers have taken efforts to cater all techniques used for overcurrent relay coordination. Different methods have been used till date for coordination of distance and overcurrent relay. These techniques include some conventional methods; artificial intelligence (AI) & nature inspire algorithm (NIA) as well as some optimization techniques. Review of application of all these methods for optimum coordination of relays along with critical comments and future scope in this area are systematically presented in this paper.