Vulnerability assessment based on power flow entropy for lines in cascading failures and its application in Sichuan backbone power grid

Based on the entropy theory and combined with the characteristics of power flow transfer and distribution of transmission lines, the concepts of transfer entropy and distribution entropy of transmission line power flow are proposed. According to the transfer characteristics of power grid weak links in different operating conditions and the change characteristics of power flow entropy under the disturbances of overload and line break, a vulnerability assessment model based on power flow entropy is proposed for transmission lines with the consideration of real time operational risk of power grid. The simulative results of IEEE 30-bus system show the reliability and comprehensiveness of the proposed method. Its application in Sichuan backbone power grid during high and low flow periods show that, the line with higher power distribution entropy and smaller power flow transfer entropy has bigger overload vulnerability; the line with heavier power flow load, higher operational fault rate and smaller power flow transfer entropy has bigger line break vulnerability; the vulnerable links of high flow period are different to those of low flow period, and the comprehensive vulnerable lines based on power flow entropy is consistent with the actual weak links of power grid.