Research On Load Frequency Control Method Based On Event-triggered Under DoS Attacks

With the development of society and the increasing requirements of industry for power quality,it is very important to eliminate the impact of load change on the frequency stability of power system.At the same time,the continuous expansion of the interconnected power system and improvement of the informatization,automation and intelligence of the power grid have also caused some new problems.In addition to the problem of excessive traffic caused by the expansion of interconnected power systems,the power grid is also more vulnerable to malicious network attacks,which endangers the safe and stable operation of the power grid.Load frequency control(LFC),as an important part of power systems,is to ensure that the frequency of whole power systems is stable in the set value,by maintaining the balance between generation power and load consumption power in power systems.With development of smart grid,when network is damaged,the impact on system stability is more serious than that of directly damaging equipment.Among a variety of network attacks,denial of service(Do S)attacks that prevents communication between networked systems are the most easily realized in the network,which will cause communication network congestion,make the control function ineffective,and finally lead power systems to instability.Therefore,it is very important to ensure the stable operation of power systems under Do S attacks.Aiming at all kinds of interference that the power system may encounter,the increase of communication data caused by the continuous expansion of interconnected power system and the possible Do S attacks,this paper carries out the main research as follows:1.This paper briefly describes the background,significance and research status of this research project,and summarizes the main research work.2.The mathematical model of load frequency control system in interconnected power system is established,and the fundamental theory is provided.3.Aiming at the problems of various disturbances and excessive communication in interconnected power systems,firstly,a linear active disturbance rejection control(LADRC)based on event triggering is designed and its stability is analyzed.Then,the particle swarm optimization algorithm is used to optimize the controller parameters and event-trigger parameters,and select the appropriate optimization performance index to make the load frequency control system achieve the optimal dynamic performance and reduce the amount of communication data in the control process as much as possible.Finally,the simulation results show that the designed controller not only has good robustness,but also effectively reduces the amount of communication data.4.Considering the instability of interconnected load frequency control systems under random Do S attacks,the stability of load frequency control system under Do S attacks is studied.Firstly,the load frequency control system model under Do S attacks is established.Then,the quantitative relationship between Do S attacks intensity and system stability is analyzed via input-to-state stability(ISS)method,study the optimization performance index of particle swarm optimization when optimizing event triggering parameters,and the appropriate signal transmission timing is determined by particle swarm optimization algorithm.Finally,the influence of Do S attacks with different intensities on system stability is analyzed through example simulations,and the quantitative relationship between Do S attacks intensity and system stability is obtained,which proves the correctness of the analysis method.5.The whole work of this thesis is summarized,and future research direction is put forward.