Identification of power grid critical lines based on comprehensive transmission betweenness

Traditional approaches to identification of critical transmission lines generally pay attention to active power flow transmission, with reactive power flow transmission ignored. Actually, transmission lines transmit active and reactive power flow at the same time. In order to take the role of a line in both active and reactive power transmissions into consideration, comprehensive transmission betweenness is proposed in this paper. We quantify the importance of a line in active and reactive power flow transmission respectively based on tracing power flow method, and then integrate them into comprehensive transmission betweenness using weighted root mean square method. Load shedding based on optimal power flow after a transmission line attacked is used to verify that transmission lines with high comprehensive transmission betweenness are critical indeed in power grid. The validity and effectiveness of the proposed approach are illustrated on a 39-bus system and a 118-bus system.