Wide-area Predictive Damping Control For Interconnected Power System Considering The Influence Of Communication Network

With the continuous growth of large-scale renewable energy access with strong randomness and volatility,and the continuous improvement of the scale and complexity of power grid interconnection,the problem of inter-area low frequency oscillations in interconnected power grids has become more and more prominent.Wide area damping controller based on wide area measurement information,as an effective measure to suppress low-frequency oscillations,has been widely concerned by many scholars at home and abroad.However,the wide-area signals transmitted over networks are likely to face with time delays,packet dropouts or even cyber attacks,which will lead to the reduction of power system stability or even directly make it unstable.Therefore,it is necessary to study wide-area damping controllers of power system to tolerate these communication influences.In this paper,a network predictive control(NPC)algorithm is applied in the large-scale renewable energy AC/DC interconnected power system,and the wide-area damping controllers based on NPC are proposed.These controllers are able to suppress the low-frequency oscillations,have strong robustness,and can effectively compensate for different communication effects.The structure of the whole thesis is listed as follows:Firstly,the model of data transmission in power communication network is established.Considering the characteristics of data transmission and communication protocol in the communication network of WAMS,the communication delay model based on round-trip time,packet dropout model based on Gilbert model and the specific mathematical model of cyber attack based on data tampering are proposed.Secondly,a wide-area predictive damping controller based on NPC algorithm is presented for the communication constraints of wide-area signal such as communication time delays and packet dropouts.The simulation results show that the controller can deal with the changes of model parameters and system operation conditions,compensate the impact of time delays and packet dropouts actively and effectively,and suppress the low-frequency oscillations of the large-scale renewable energy power system.Thirdly,a resilient wide-area predictive damping controller based on SNPC(Secure NPC)algorithm is proposed for cyber attacks.And an information technology security system is designed to ensure the integrity,confidentiality and authenticity of communication control signals.The simulation results show that the controller can compensate the impact of communication constraints and cyber attacks actively and effectively,and suppress the lowfrequency oscillations of the large-scale AC / DC interconnected power system.Finally,a multi-resilient wide-area predictive damping controller based on MNPC(MultiNPC)algorithm is presented for multiple inter-area low frequency oscillations.The controller extends the NPC algorithm based on the single-input single-output system to the multi-input multi-output system.The simulation results show that the controller can deal with time delays,packet dropouts and cyber attacks in the multiple communication channel actively and effectively,and damp multiple low frequency oscillations.