Power Grid Vulnerability Assessment Based On Risk Theory

Power grid vulnerability assessment is a new concept of security assessment,it can more effectively reflect the security level of the grid. Previous methods of vulnerability assessment are based on reliability theory or complex network theory,but the vulnerability of power grid is not only related with the network structure and device parameters,but also related with the real-time operating conditions and constraints. So a new assessment method is proposed based on complex network theory and risk theory in this paper. Firstly,establishing the topological model of power grid based on complex network theory,using the node importance indicator and the improved line betweenness indicator to identify the vulnerable sources in power grid. The fault model of vulnerable sources is established by condition-based maintenance data and the failure rate is calculated by the health index of electrical components. Then simulating the vulnerable source components fault and using the utility theory to assess the severity of components fault consequences,calculating the corresponding integrated static risk indicators. Finally, based on the network structural indicator and integrated static risk indicator define the node vulnerability degree indicator,line vulnerability degree indicator and power grid vulnerability degree indicator. A regional power grid is analyzed with the proposed algorithm,the results show that the vulnerability degree indicators defined in the paper can effectively overcome the shortcomings of previous methods from single aspect to assess the power grid vulnerability. Meanwhile,the method proposed improves the precision in distinguishing the vulnerable part of power grid, it is verified that the proposed method is rational and effective.