Vulnerability Assessment Of Cyber Physical Power System Based On Critical Power Line Attack

The deep coupling of the power grid and the information network brings intelligence and automation,but also makes the Cyber Physical Power System(CPPS)face a large number of security,vulnerability and other challenges.Specifically,the fault can be cascaded from the power grid to the information network,and vice versa.In view of the above background,evaluating the vulnerability of CPPS under different coupling strategies based on the attack effect of key lines in the power grid can avoid large-scale cascading failures in the power system.If only considering the structure or state characteristics of the power grid can not accurately identify the critical line,in this paper,the structural vulnerability and state vulnerability of the power grid are evaluated on the power line.Among them,the structural vulnerability adopts the improved power flow betweenness of the line,and the state vulnerability adopts the weighted power flow transfer entropy of the line and the variance load ratio,and the importance weighted index of the power line is proposed.Set the optimal weight reasonably to obtain the key lines in the power grid.Through the simulation test of IEEE 39 and IEEE 118 node systems,the top ten lines in the order of comprehensive weighting values in IEEE 39 and IEEE 118 systems are obtained,and the effectiveness of the proposed comprehensive weighting index is verified under different attack methods.The CPPS is modeled based on the complex network theory,and the "gravity-power gravity"coupling strategy is proposed on the basis of the failure model of the information node.Consider the topological characteristics of information nodes through the "gravity" index;considering the topological structure and electrical characteristics of the power node through the "power gravity"index,and coupling with the "degree-electrical degree","degree-betweenness" coupling and random coupling strategies are compared.One-to-one connections are used between nodes.Launch an attack on the critical line of the power grid,and the vulnerability of the power grid under different coupling strengths and different attack methods is obtained.It is found that increasing the CPPS coupling strength under random attacks can improve the performance of the power grid.At this time,the robustness of the power grid is highest when the "gravity-power gravity"coupling is adopted;in addition,compared with random attacks,CPPS is more susceptible to malicious attacks.During an attack,the greater the coupling strength,the higher the vulnerability of the power grid.At this time,the random coupling strategy is the best.