Research On The Impact Of Cyber-attack On The Security Of Physical Power System And Its Risk Assessment

CPS integrates computing,network and physical environment in a multidimensional space,and deeply integrates the computing,communication and control technology,which makes the physical system have the ability of real-time perception,dynamic control and communication services.The power system,which is a typical large-scale cyber-physical system,is closely integrated with the communication network infrastructure that supports it For the electric cyber physical system(ECPS),when the information network is attacked(or failure),it may lead to the cascading failure of the whole power system,which will eventually lead to catastrophic blackout.For instance,in 2005 the Supervisory Control and Data Acquisition(SCADA)systems in at least three areas of power utilities in the Ukrainian power system were attacked by BlackEnergy virus resulting in the large scale blackout.The reliability analysis method based on graph theory is applied to study the security of network topology in macro view.However,it is difficult to apply to study the impact on ECPS and the safety assessment of cyber-attack inside the ESP zone without cooperating with model simulation method.In view of the above problems,this paper carries on the following research.(1)OPNET and PSS/E are used to build the model of the electric cyber physical system.Furthermore,influence of the DDoS attack on the message transmission delay and its threat to the physical power system security are investigated in this paper.The results show that the network structure plays a light role in defending against the cyber-attack that has invaded the ESP.The larger the message traffic in the normal operation,the greater the influence of the communication delay.The critical attack strength of information security is less than that of physical security.When the critical attack strength of information security is greater than that of physical security,the cyber-attack can damage the physical power system.(2)According to the depth interaction between the physical domain and the information domain,a method of security risk assessment on the ECPS is proposed in this chapter,which is used to evaluate the impact of information system failure on the physical power system.From the perspective of defense,this paper develop a method of optimal allocation of finite defense resources.The results show that,Comprehensive evaluation the risk of information nodes in power system under cyber-attack,it is need to consider the possibility of successful intrusion of information nodes in the information domain,active loss of physical nodes in the physical domain resulting from damage,and the risk of cyber-attack across the information domain to threaten the physical domain.Compared to the defense resource average allocation method,the dynamic allocation method based on risk is a better allocation method on defense resource.Because it is a more rational allocation method on allocating limited defense resources.It greatly reduces the average risk of information nodes,but also reduces the difference in value of risk between different information nodes,and effectively avoids nodes with great risk under cyber-attack.