Research On Risk Assessment And Active Defense Method For Cascading Failures Of Electric Cyber-Physical System

With the rise and development of the smart grid,the model power system has developed into a complex integrated network system that integrates the information system and the power system.The high integration of information system and physical system brings convenience to the development of power grid s,it also brings new challenges.For the electric cyber-physical system,initial failures include physical failures and information failures.Physical failures will not only change the load distribution of the network,but also cause communication network failures,and even cause cascading failures.The potential failure of the information layer may not directly lead to the failure of the power grid,but it will increase the probability of power grid outage,and increase the risk of power outage;due to weather disasters and man-made attacks,coordinated failures of the power grid and communication network,and even cascading failures.It can be seen that it is necessary to carry out risk assessment of cascading failures in electric cyber-physical systems,and it is urgent to propose research methods to suppress cascading failures.It has important theoretical value and practical significance for understanding the mutual influence mechanism and risk management of power grid and communication network.This paper takes the main object of electric cyber-physical system,and investigates the electric cyber-physical system modeling methods.Aiming at the risk of electric cyber-physical system and cascading failures,risk assessment of cascading failures of electric cyber-physical systems based on information flow control;The maximally disjoint dual paths is configured in the information network layer to suppress the cascading failure of the electric cyber-physical system,and improve the robustness of the electric cyber-physical system.The main work is as follows:(1)Risk assessment of electric cyber-physical system cascading failure based on information flow control.Aiming at the influence of communication network information flow control on electric cyber-physical system,a model of information flow control delay is established,combined with the optimal DC power flow model,a SDN-based information flow control delay effectiveness model is established,and use the loss of load rate as an evaluation index to perform risk assessment.Finally,the simulation experiment is carried out with the IEEE-14 node examples and the IEEE-39 node examples,the experimental results show that considering the information flow control in the risk assessment can effectively reduce the scale of the cascading failure of the electric cyber-physical system and reduce the loss of load rate.(2)Active defense method based on information space configuration for maximally disjoint dual paths.Aiming at the problems of high cost and poor flexibility in the active defense method of cascading failure of electric cyber-physical system,according to the real working state of the communication network,based on the interdependence between the power grid and the communication network,a cascading failure propagation model of electric cyber-physical system is established,and the maximally disjoint dual path is configured in the communication network to reduce the number of failed nodes in cascading failures.Simulation experiments are carried out using IEEE-14 node examples and IEEE-39 node examples,the experimental results indicate that the method can effectively suppress the cascading failure of electric cyber-physical system under both random attack and intentional attack,the improve the robustness of interdependent power grids and communication networks.