Research On Power CPS Voltage Control Strategy Under Data Tampering Attack

Advanced computing and communication technologies bring opportunities to the development of the power system,promote its intelligence and informatization,but also increase the threat from the information system.As a result,various power businesses will be monitored and used by attackers during the implementation process,causing information leakage or decision errors in the power cyber-physical fusion system(CPS),and causing various economic and social losses.As a very threatening network attack,data tampering attacks are often used by attackers to cause harm to the power grid.With false data injection attack,attackers can secretly inject false data into a smart meter measurement or state estimation monitoring mechanism,thereby affecting system judgment and causing voltage overrun and other issues.Therefore,in the context of deep coupling of power cyber-physical systems,the existence of cyber attacks makes power CPS need to be further studied.The modeling and analysis must be able to integrate the attack situation on the information side and the dynamic change on the power side in order to propose more effective control and improvement strategies.This paper mainly proposes new control strategies for voltage instability caused by tampering attacks.The main research contents include:(1)The complex network theory is used to analyze the importance of the nodes in the information communication network topology.Secondly,based on the vulnerabilities of the equipment,the attack graph is used to quantify the probability of the information node attack associated with the vulnerabilities.As a consequence,the importance of infrastructure in power CPS is comprehensively analyzed by taking relevant power side indicators as consequences.The results evaluate the criticality of secondary equipment and provide guidance for power CPS defense.(2)Based on the interaction effect and fault propagation characteristics of power CPS information side and physical side,this paper analyzes the intrusion mode of network attack to gain control and tamper attack,constructs the intrusion model of attack and information transfer model by using generalized random Petri net theory,and calculates the probability of successful injection of malicious packets.Then,the influence of tamper attack on voltage was analyzed.Through the analysis of voltage regulation model,a unified model of power CPS voltage regulation based on Petri net theory was constructed.(3)Based on the established pressure regulating model,On-load tap changer(OLTC)is selected as the regulating device,and the pressure regulating strategy under tamper attack is proposed.In order to ensure the safe and reliable operation of the system under attack,and to identify the occurrence of attack as far as possible,the event triggering mechanism is added into the policy,so that the voltage comparison can be made in time when the attack event is detected,so as to avoid the instability of the system due to delayed action.The voltage regulator is strategically located near key measuring devices to reduce the impact of network attacks on the system,and particle swarm optimization is used to find the most suitable tap adjustment point to maintain stable system voltage.Finally,the effectiveness of the method is proved by numerical examples.Reasonable use of this method can maintain the security and stability of power system under tamper attack.