Network Security Threat Determination And Defense Of Electric Vehicle Charging System Based On Propagation Probability Analysis

With the large-scale access of smart devices to the power grid,the integration of various network communication technologies and power is also becoming more and more closely,which will be very conducive to boosting the construction of the country’s smart grid.However,opportunities and dangers coexist,and the high integration with smart devices will make the power side face more attacks and threats from the network.Because of the electric vehicle charging system composed of electric vehicles and charging piles has the characteristics of large load and developed network communication.Once attackers take this as a breakthrough point,they will carry out cyber attacks on the power system,resulting in information leakage or decision-making mistakes.These will be lead to unpredictable losses and adverse effects on the economy and social stability.Therefore,it is necessary to deeply study the cyber attacks propagation characteristics of electric vehicle charging system under cyber-physical fusion,so as to propose reasonable and effective defense and control strategies.This paper studies the cyber attacks method,attack transmission process,attack impact,and countermeasures of the electric vehicle charging system under the fusion of information and physics.The details are as follows:(1)Based on the cyber-physical system model of the distribution network,the architecture and security of the electric vehicle charging system are analyzed in detail,and the attack influence is analyzed for different targets and different forms of attack behavior;then the physical properties of the charging system are analyzed.Through the analysis of the operating characteristics of the charging system,it shows the importance of the safety of the electric vehicle charging system to the power system.This result can provide physical-side defense elements for cyber-attacks against charging systems.(2)Then decompose the cyber attacks process,so as to propose corresponding security protection measures and model network protection units,including authentication model,firewall model and network device configuration security model;and then target the three cyber attacks that have the greatest impact on the attack.After that,using model and simulation to analyze the probability of success of each attack.On this basis,combined with the situational awareness of the electric vehicle charging system,the threat level and attack propagation of the electric vehicle charging system from the information side and the physical side are analyzed.This result can provide information-side defense elements for cyber-attacks against charging systems.(3)In order to fully deal with the cyber-attacks of the electric vehicle charging system under the fusion of cyber-physics,and effectively ensure the safe and stable operation of the charging system,based on the information-side defense elements and physical-side defense elements obtained above,the network with the greatest possibility obtained by simulation is analyzed.The voltage instability caused by the denial of service attack to the charging system,combined with the threat level of cyber attacks in the electric vehicle charging system,this paper proposes two different defense strategies: take a certain safety margin as the dividing point,and exceed this safety margin.The cut-off strategy is adopted for the degree of protection,and the voltage regulation strategy is adopted within the safety margin range.Finally,the effectiveness of the proposed strategy is verified by means of simulation.