Cascading Fault Modeling And Vulnerability Analysis Of Power Cyber Physical System Considering Dependency Degree

The proposal put forward by President Xi Jinping at the United Nations summit: "Building a global energy Internet to promote a clean and green way to meet the global electricity demand." The initiative has accelerated the intelligent development of the power grid.At the same time,with the development of 5G technology,and the Internet of Things,the investment of more intelligent equipment and the use of information technology,the traditional power system has gradually evolved into a Power Cyber Physical System(Power CPS)that is deeply integrated with the cyber network and the power grid.The use of intelligent equipment,and advanced information technology has greatly improved the automation degree of the system and the efficiency of power grid operation,but at the same time,it has also brought new security issues to the system.Therefore,from the overall point of view,it has important research significance for the security assessment and analysis of Power CPS.Based on the above research background,the modeling,cascading fault propagation,and vulnerability of Power CPS are mainly studied.The main research contents are as follows:Firstly,establish a real-time model of a power CPS system.A static model of the Power CPS is established by using the interdependent network.Based on the unity of the structure of the power cyber network and the Network Control System,the True Time module is used as the simulation model of the Network Control System,and the dynamic model of the Power CPS is built according to the coupling relationship between the two networks in the static model.Realize real-time information transmission and scheduling control in Power CPS.Taking the IEEE30 bus Power CPS as an example,the system model is established,and the optimal cost allocation is used as the control strategy to verify the accuracy of the model.Secondly,build a cascade fault diagram with temporal relationship considering the degree of interdependence.According to the structure and function of the cyber network,combined with the operation status of the cyber network,a method for identifying the degree of interdependence between the two networks is proposed.Using the fault propagation model under the interdependent network,a cascaded fault chain model is established considering the information exchange of the Power CPS and the operating characteristics of the power system under the dependency degree.The cascading fault graph is constructed by using the mapping relationship to reflect the fault propagation path and time sequence relationship.Based on the IEEE30 system dynamic model,the fault chain and cascading fault diagrams are constructed when the initial fault occurs in branch 1,and the fault propagation path is analyzed.Finally,a vulnerability index is constructed to analyze the system vulnerability under different attack strategies.Comparing and analyzing the vulnerability of the Power CPS under different attack strategies,it is concluded that the target attack is more destructive to the network and the system is more vulnerable.The out-degree reflects the propagation characteristics of the fault,and the in-degree reflects the characteristics of the node affected by the fault.Considering the degree of interdependence between the two networks,an identification index of key nodes in the cyber network is constructed.Then,using the IEEE30 system to analyze the accuracy of the key node identification indicators,it is found that the improved key identification indicators can more accurately identify the key nodes of the cyber network,that is,the information nodes that are attacked less can lose more load.