Time overcurrent relay coordination using the Levy flight Cuckoo search algorithm

Over-current relays provide primary as well as backup protection to electrical distribution systems. These relays should be coordinated and set at the near optimum values, to minimize the total operating time and hence ensure that least damage is caused when a fault occurs. While they provide backup protection, it is also imperative to ensure that their settings should not cause their inadvertent operation and subsequent sympathy trips. This paper describes a Cuckoo Search algorithm for optimal time coordination of these relays. The algorithm has been implemented in MATLAB software and tested on several systems, out of which two have been illustrated in this paper. The results are verified by comparing it with the linear programming method. The novel feature of this paper is the application of the Cuckoo algorithm to the problem of over-current relay coordination.