Identification of Weak Nodes in AC/DC Hybrid Power Grid Based on Entropy Theory

With the successive operation of large-scale HVDC transmission system, the cascading failure risk of hybrid grid is also increasing. In the past, the identification of weak nodes does not involve the AC/DC hybrid power grid. Therefore, based on the entropy theory, this paper proposes an integrated entropy index weak node identification method for AC/DC hybrid power grid, which considers the topological structure entropy, power flow transfer entropy and voltage margin entropy, to measure the severity of the fault from the structural characteristics and actual operation characteristics of the hybrid power grid. At the same time, the security evaluation of the modified IEEE39 bus system is carried out, and the effectiveness of the proposed method is verified by the comparison of simulation results and the verification of weak node attack. This method can find the weak nodes in hybrid power grid in time, and can effectively prevent the occurrence of blackout.