Research On Security Risk Assessment And Attack-defense Game Of Smart Distribution Network Cyber-physical System

In order to achieve the goal of low-carbon economy and sustainable development in the context of the global energy crisis,the distribution network that accommodates a large number of distributed energy sources,new loads and energy storage equipment has become the focus of research in the electric power academic community.The traditional distribution network has evolved into an information The Cyber-Physical System(CPS)of the distribution network,which is highly coupled physically,not only supports the safe and stable operation of the distribution network,but also introduces risks into it.In order to ensure the safety and reliability of the distribution network CPS,it is of great practical significance to fully excavate the high-risk links on both sides of the system,and to carry out the security risk assessment of the distribution network CPS under the background of network attack and attack-defense game.On the basis of the existing research results,this paper considers the distribution network CPS distributed control logic and control method,establishes the whole network unified model and the system global risk analysis model conforming to the distribution network CPS topology structure and operation characteristics,and conducts DGs collaboration Quantitative risk assessment of master-slave offensive and defensive game systems under control.(1)Based on the multi-level physical entity architecture and functional characteristics of the distribution network CPS,abstract modeling of the distribution network CPS.Considering the intra-layer and inter-layer topological connection relationship and data flow process,establish a secondary device layer model,a secondary device-physical interface model,and a secondary device-information interface model to describe the information-physical coupling relationship and secondary device node master-slave attributes,Finally,the CPS unit model of the distribution network is constructed through the association matrix,and then the unified model of the entire CPS network of the distribution network is established according to the multi-level regional regulation mode.Taking the centralized feeder automation process of 33-node power distribution system as an example,the model building process is briefly explained,and the feasibility of the model is verified.(2)On the basis of the unified model of distribution network CPS of the whole network,construct the distribution network CPS risk analysis model under the data blocking method and data tampering method.Study the impact of network attacks on physical lines and information measurement and control processes on distribution network CPS,consider the distribution network fault recovery process under the influence of data attacks,and establish security risk assessment indicators from two aspects of fault loss and fault recovery.The system is used to analyze the risk of distribution network CPS under different attack scenarios.Taking the 3-feeder distribution system as an example,the applicability of the risk analysis model is verified.During the research,it was found that in the maintenance and operation planning of the distribution network,it is necessary to provide more protection to the outlet circuit breaker and the terminal equipment of the tie switch;the series-parallel structure of the distribution network lines under different attack modes will also affect the system risk level.(3)From the perspective of attackers and defenders,establish a dynamic attackdefense game model with complete information.On the basis of the system model,the communication topology weights of secondary equipment nodes are considered,and the risk propagation process of DGs and their terminal equipment in the process of CPS scheduling of distribution network in the process of unilateral attack and bilateral coordinated attack is finely described,from the total amount of attack resources,defense resources Sensitivity analysis of system risk is carried out from four perspectives: total amount,attack time,and dispatch power ratio.Taking the 33-node power distribution system as an example,the effectiveness of the attack-defense game risk assessment method is verified.During the research,it was found that the DG and its terminal equipment directly connected to the "dominant" DG need to be protected;the investment of attack resources has marginal cost effect;Attack,the attacker can get the most benefit.