Research And Verification Of Trust Guarantee Mechanism Under Multi Scenario Access Of Station-Equipment

In recent years,the continuous improvement of the business level of intelligent substation has promoted the rapid innovation of relevant technologies.The deep integration of information system and physical system has played a directional role in the development of intelligent substation.There are certain security vulnerabilities in the establishment and improvement of intelligent substation cyber physical system,which is easy to be exploited by attackers.Therefore,the network attack of substation has spread all over the world.As one of the most common equipment in intelligent substation,the stability and reliability of its operation are directly related to the safe operation of substation.The diversity of terminal types and complex operation environment in the station significantly increase the difficulty of security,so that the risk is easy to spread to the whole substation system through the terminal.It can be seen that the terminal security capability is weak,and it is easy to become a springboard for attackers.There are many cases of invading the substation through the terminal.The most representative is the blackout in Ukraine in 2015,and the terminal safety should be paid attention to.In this paper,various communication networks and terminal access scenarios of intelligent substation are deeply studied.By constructing the terminal equipment risk assessment scheme,the terminal security is analyzed,and the terminal access process is constructed to verify the accuracy of the risk assessment scheme.Finally,the reliable guarantee measures of terminal access are given according to the experimental results,so as to prevent the potential safety hazards caused by terminal equipment and ensure the reliable operation of intelligent substation.(1)With the help of cyber physical system model,this paper analyzes the structure and characteristics of intelligent substation,creates the cyber physical model under intelligent substation,analyzes the interaction between physical system and information system,and the security risk caused by the coupling of energy flow and information flow.Combined with the substation communication specification and the terminal access requirements of the power industry,the terminal network access model is constructed.Combined with the terminal structure and the communication interface with the substation,the hidden dangers of the terminal itself and the hidden dangers brought by accessing the substation are analyzed.By analyzing the characteristics and security of most communication scenarios in substation,the security control scheme of terminal multi scenario access to substation is given.(2)In order to realize the quantitative risk assessment of terminal equipment in intelligent substation,firstly analyze the intrusion behavior of attackers according to the topology of substation,then establish the quantitative formula of terminal risk factor by constructing terminal value coefficient and quality coefficient,and quantify the risk according to the defense ability of other equipment on the communication link,Then,the risk propagation path is obtained by using the equipment connection matrix and the risk propagation probability formula.Finally,the attack intensity and communication scene security factor are added to the evaluation index to build a complete risk evaluation scheme.(3)Taking t1-1 substation as the research object,extract the functional nodes and find out their corresponding equipment,calculate the risk factor according to the equipment vulnerability and the terminal risk quantification method,simulate the risk propagation process using the risk assessment scheme constructed in this paper,and verify it with Simulink simulation tool.Taking the terminal CPU utilization and the data transmission time between the terminal and the secondary equipment of the substation as the terminal risk detection index,this paper analyzes the importance of the four attributes in the terminal quality coefficient,and analyzes the risk factors of the terminal under different communication scenarios,so as to give the credible guarantee scheme.