Abstract: Firstly， the slow and fast dynamic processes of the complex networks were given and analyzed respectively for the power grid and the disaster， and the analytic strategy of the reciprocal impact between the power grid and disaster was proposed， in which twelve aspects of the impact were studied and discussed in detail. A novel method was proposed to identify the critical lines and nodes of the power systems on the basis of the maximum flow theory and reciprocal effect between the power grid and disaster. A synthetic performance index was defined as the basis of identification which not only could reflect the internal operation characteristics but also the external operation characteristics of the power system under the influence of disaster. Finally， an example of the power grid in Tibet was provided to test the proposed method， and the result showed that the method can effectively identify the critical lines and nodes under the influence of the disaster， and is appropriate for vulnerability estimation of power system influenced by disaster， which demonstrates the rationality and validity of the proposed method.

Key words: power grid, disaster, complex networks, identification of critical lines and nodes；vulnerability estimation