Security Control Of Power Cyber Physical System Under Malicious Attack

With the continuous progress of communication,control and computing technology,the reliability and security of Cyber-Physical System（CPS）have attracted more and more attention.As the scale of the power system continues to increase,smart components,sensor measurement units and communication technologies are widely used in the power system,and the traditional power grid system has gradually evolved into a smart grid system with CPS characteristics.The information layer,physical layer and control decision layer of the smart grid system are connected to the communication network,and the reliable information exchange is realized through the communication channel.Although this greatly improves the efficiency of grid operation,it also makes the power system more coupled,complex and open.In this paper,by using adaptive,state estimation,sliding mode control and other technologies,the security control of power CPS systems under malicious attacks is studied,involving adaptive sliding mode control under hybrid attacks,attack identification and security control under false data injection（FDI）attacks,optimal adaptive sliding mode control of power CPS system under process attack,and state estimation and security control of nonlinear system under malicious attacks.The main research contents of the paper are as follows:（1）For the power CPS system attacked by FDI attacks,an adaptive attack identification scheme is developed based on a robust adaptive sliding mode observer and a sliding mode control strategy is designed to eliminate the effect of FDI attacks.First of all,the power CPS system model attacked by false data injection is given,and a robust adaptive sliding mode observer is designed for the attacked power system.Secondly,an adaptive attack identification scheme and a security control strategy are designed to reconstruct the attack signal and eliminate the impact of FDI attacks,respectively.Finally,the effectiveness of attack identification and security control strategy is verified by simulation.（2）A sliding mode control scheme is designed based on the adaptive method for the power CPS system under mixed attack.First of all,according to the attack characteristics,the model of the power CPS system under mixed attack is given.Second,considering the influence of disturbance,we design an adaptive security control strategy with H_?performance using an adaptive mechanism.Finally,the feasibility of the designed adaptive sliding mode control strategy is verified by simulation.（3）For a class of nonlinear power CPS systems subject to process attacks,we design a sliding mode control strategy based on the intermediate variable observer.Firstly,an intermediate variable observer is designed to estimate the system state.Secondly,we reconstruct the attack signal and design a state estimation-dependent integral sliding mode function.Then use the reconstructed attack signal and output error to design a security control strategy to eliminate the impact of the attack.Finally,the tracking effect of the intermediate variable observer and the effectiveness of the safety control scheme will be verified by simulation.（4）For a class of power CPS systems under process attack,we design an adaptive integral sliding mode control strategy based on robust observer with H_?performance.Firstly,the mathematical model of power system with cyber-attack is established and a robust observer is designed,and the estimated system state is used to establish integral sliding mode function.Secondly,we analyze the upper bound on the state deviation after the system under malicious attacks.Thirdly,we will design a new control strategy using the adaptive mechanism,in which we will obtain the optimal control gain by using guaranteed cost control.Finally,a power system with3 generators and 6 buses will be taken as an example to verified the feasibility of the proposed theory.Finally,we summarize the research content of this paper,and based on other problems encountered in the research,we have an outlook on the next steps to be carried out in this topic.