Research On Risk Assessment And Security Defense Method Of Grid CPS Based On Predicted Accident Scene

With the development of cyber physical systems in the industrial field,power systems and other industrial systems are provided with a faster and more convenient mode of operation,while the power system relies heavily on information systems,and the security problems that follow are not allowed.Neglecting,it is of great practical significance to carry out research on the safety defense method of grid cyber physical system.Therefore,this thesis studies the risk assessment and security defense methods of grid cyber physical system under the scenario of expected accidents.Firstly,this thesis introduces the interaction process between the three components of the cyber physical system and the energy flow-information flow.It extracts the key attributes of the information system and extracts the key attributes and constructs the initial accident scene.Considering the huge number of initial accident scenes,the scene filtering is carried out.In addition to scene aggregation and scene correlation,the expected accident scenario is finally obtained.This method can be used for offline and real-time alarm data processing and analysis of power systems.Secondly,the scenario of the expected accident caused by fraudulent data is identified,and the state estimation method without fraudulent data is adopted.In order to improve the accuracy of state estimation,the SCADA system data and the WAMS system data are merged from four aspects:data component,data time profile,data accuracy and data frequency.The generator exit power is taken as the observation sequence,and the state vector is obtained based on the dynamic programming principle.Achieve higher-precision fraudulent data detection and perform consistency check of state vectors.The example analysis shows that the method can accurately identify the expected accident scene caused by fraudulent data.Then,from the perspective of the grid to deal with the accident scene state and external intrusion,an all-round comprehensive risk assessment index system including user security risk,grid operation risk,power communication network risk,human factor intrusion risk and environmental factor intrusion risk is established.Then,the calculation methods of each index are given,and the risk grading and risk quantification are carried out.A weighting method for risk assessment index based on analytic hierarchy process-entropy coefficient method is proposed,which improves the defects of large difference and poor adaptability of entropy weight method.Get the results of the comprehensive risk assessment of the expected accident scenario.The method gives detailed risk assessment steps.The grid dispatcher formulates a security defense strategy after considering the risk assessment results,paving the way for security defense.Finally,on the basis of predicting the comprehensive risk assessment of the accident scene,the viewpoint of engineering game is introduced,and the security defense method of the expected accident scene based on evolutionary game is proposed.The method takes the expected accident scene as the attacker strategy,and gives four defense party strategies.The comprehensive risk assessment result is used as the fitness function,the defense party strategy is combined,and the optimal strategy is solved by the evolutionary stable equilibrium to obtain the specific security defense.Program.After the example is verified,the method can reasonably select the defense strategy,which can improve the stable operation capability of the distribution network to a certain extent and reduce the load loss.