Coordinated Defense-conventional Planning Models Of Power Systems For Defending Against Coordinated Cyber-physical Attacks

With the large-scale application of information and communication technology in power systems,the modern power system has developed into a complex cyber-physical system(CPS).However,the current operation of the power system is facing a considerable challenge,which is the attack against CPS,especially coordinated attacks involving the cyber-attack and the physical attack,which seriously threaten the safety and reliable operation of power systems.Therefore,it has important theoretical significance and practical value in engineering to model and analyze the coordinated cyber-physical attacks(CCPA),come up with an effective defense planning scheme,combine it with conventional planning to obtain more scientific planning schemes,and provide a more scientific decision-making basis for planners.Supported by National Science Foundation for Distinguished Young Scholars(No.51725701),this paper focuses on the modeling of CCPA,defense planning strategy based on coordinated generation and transmission expansion planning(CGTEP),and coordinated conventional-defense planning.The main research contents are as follows:In order to accurately quantify and evaluate the impact of CCPA on the power system,this paper establishes a bi-level coordinated cyber-physical attacks optimization model from the perspective of the attacker based on the background of the cyber-physical system.The attack behavior of the attacker is described by the upper-level model,and the objective function is the maximum load shedding caused by the attack.The scheduling behavior of the operator is described by the lower-level model,and the objective function is the minimum load shedding caused by the attack.The model involves traditional physical attacks that damage the adequacy of the system’s transmission capacity and generation capacity,as well as load redistribution(LR)attack of cyber attacks that maliciously tamper with the measurement data.At the same time,the mechanism of coordinated attacks to avoid resulting in islanding is also considered.The model is transformed into a single-level optimization model for solution using Karush–Kuhn–Tucker(KKT)conditions,and the Gurobi toolbox is used to solve the problem.Case studies on the IEEE RTS-79 system were performed and the results show that CCPA can achieve better attack effect.In order to effectively defend against CCPA,a tri-level robust defense planning model based on the coordinated generation and transmission expansion planning(CGTEP)is proposed.In the process of modeling,the upper-level model represents the perspective of the planner,with the aim of minimizing the load shedding of the planning system after the attack,and the overload problem that may be caused by the false power flow of transmission lines is considered;The middle-level model stands at the viewpoint of the attacker.It aims at generating an optimal CCPA scheme in the light of the planning strategy determined by the upper-level model to maximize the load shedding caused by the attack.The optimal operation behavior of the operator is described by the lower-level model,which minimizes the load shedding by defending the CCPA attack.The tri-level model is iteratively solved by the column and constraint generation(C&CG)algorithm,which decomposes the defense model into the master problem and the subproblem.Case studies on a modified IEEE RTS-79 system were performed to investigate the defense effects of CGTEP.The results show that the defense planning strategy proposed in this paper can effectively defend against CCPA.In order to improve the expansion planning strategy,a tri-level coordinated defense-conventional robust optimization planning model is proposed in cooperation with defense planning,considering the requirements of conventional planning and CCPA that may be suffered in the future.It also takes into account the uncertainty of load and output of renewable energy generators during the planning period.The upper-level model represents the perspective of the planner and determines CGTEP and wind turbine expansion planning strategy to minimize the total planning cost,and the nominal situation of the planning system and the actual situation of the planning system under the worst operation scenario are considered;The middlei-level model selects the operation scenario that maximizes the load shedding of the planning system considering the uncertainty of attackers,load and output of wind turbines.The optimal operation behavior of the operator is described by the lower-level model,which minimizes the load shedding of the planning system in the worst operation scenario.The C&CG algorithm is used to solve the coordinated planning model.Case studies based on the modified IEEE RTS-79 system were performed.The results show that the coordinated planning strategy is more effective in dealing with disturbance of future uncertainty.