Determination of break point set for directional relay coordination based on analysis of breaking loop

Modern power system networks are often multi-loop structured. The coordination of the directional relays in such network poses difficulties. In order to ensure coordination, the starting relays, called break points, must be determined through network analysis firstly, which is an important and complicated process. Based on the theoretic analysis of converting mesh network into radial network, an algorithm for determination of break point set (BPS) for directional relay coordination grounded on analysis of breaking loop is proposed, which is implemented easily within the adjacency matrix of power network. This algorithm reduces the complexity of the problem by exploiting the available coupling degree of loops in power network. Examples are presented to verify the validity and simplicity of the algorithm.