Research On Vulnerability Of Power Cyber-Physical System Under Malicious Attack

With the advancement of national information construction,advanced information technology and intelligent sensor equipment have been widely used in power system.Modern power system has developed into power cyber-physical system with deep coupling of cyber and physics.Aiming at the new security risks and more diversified malicious attacks that the system may suffer after the deep fusion of cyber elements,it is of great significance to establish the model of power cyber-physical system,study the malicious attack model and fault propagation mechanism of power cyber-physical system,carry out system vulnerability analysis and propose defense strategies to improve system vulnerability.In this paper,a two-stage malicious attack model of power cyber-physical system is established.The attack resources are extended from conventional load to data center load with spatial transfer characteristics.The vulnerability of power cyber-physical system in this scenario is analyzed,and corresponding defense strategy is proposed to improve system vulnerability.The main research results of this paper are as follows:(1)A two-stage malicious attack model of power cyber-physical system is established.A new malicious attack path of power cyber physical system is explored through the cooperation of DoS(Denial of Service)attack on the cyber system side and improved electricity price attack on the power system side.Firstly,the network model of power cyber physical system is established based on Louvain community discovery algorithm.On this basis,a two-stage malicious attack model is proposed.In the first stage,DoS attack is carried out on the access layer nodes of cyber subsystem,which destroys the observability of power subsystem lines.The attack model is established by maximum flow theory and KKT(Karush-Kuhn-Tucker)condition.In the second stage,the electricity price attack is carried out on the nodes of the power subsystem.The demand response of the load is used to cause the unobservable line to be overloaded and disconnected.Based on the traditional electricity price attack,the observability information of the power subsystem line is added and the objective function is improved to establish the attack model.The vulnerability of the power cyber-physical system in this scenario is analyzed.(2)A two-stage malicious attack model of power cyber-physical system considering data center load is established.Firstly,the energy consumption characteristics of the data center are modeled at the CPU level.The M/M/1 queuing theory is used to construct the service quality constraint,and the data center transmission optical fiber network is established to describe the transfer path of the data load.The economic optimization problem of the data center operator is embedded into the main problem of the two-stage attack through the KKT condition.A twostage malicious attack model considering the data center load is established.It is verified that the data center load can realize the spatial transfer of active power demand.At the same time,the economic optimization of the data center operator makes the data center nodes that are not directly attacked indirectly join the attack process,which expands the attack range and further enhances the potential of the two-stage malicious attack of power cyber-physical system.The vulnerability of the power cyber-physical system in this scenario is analyzed.(3)A defense strategy of power cyber-physical system under two-stage malicious attack is proposed.For the first stage malicious attack of power cyber-physical system,the objective function and related constraints of the defender ’s perspective are first constructed,and then the fitness function is constructed by the penalty function,and the optimal defense resource allocation scheme is obtained by the particle swarm optimization algorithm.For the second stage malicious attack of power cyber-physical system,the key node identification work is first carried out.Based on the entropy theory,the line observability information obtained by the cyber subsystem is integrated into the index evaluation,and the node criticality index in the second stage malicious attack scenario is established.Based on this index,a specific defense resource allocation process is proposed.The effectiveness of the proposed two-stage defense strategy is verified,and compared with the defense resource allocation scheme established based on the traditional node criticality index,the system loss after the attack is more effectively suppressed,and the superiority of the proposed index is verified.