Study on critical lines identification

Critical lines may have serious impacts on large scale blackouts and cascading failures in power grids. Based on complex network theory and network flow theory, the flow betweenness is proposed as line critical index, which measures the constraint degree of network transmission capability. The drop of net-ability and the fault critical clearing time are chosen to confirm the vulnerability of lines identified by the presented method. Numeric example of IEEE 39-bus system demonstrates that the proposed method is effective and practical, and the max-flow betweenness can reflect the specific features of both operation state and network structure.