A new application of graph theory for coordination of protective relays

The coordination of protective relays of multiloop networks is a tedious and time consuming process. The complicated part of this process is the determination of a set of relays referred to as the break-point set (BPS), with a minimal size to start the coordination procedure. This letter introduces a new graph-theoretical approach to determine the BPS. This method reduces the complexity of the problem, by exploiting the available sparsity of the dependencies among relays in protection systems.