Research On Cyber Physical System Co-simulation And Distributed Protection And Control Method For Smart Distribution Network

With the rapid development of distributed generation,electric vehicles and other new equipment,a large number of equipment are connected to the distribution network,making it large and complex.Distribution network is changing to the direction of distributed,shared,power supply and user interactive energy Internet,so the traditional centralized protection and control methods have been unable to meet the demand.The distributed protection and control method has the advantages of simple logic,high reliability and easy expansion,which is especially suitable for complex distribution network.However,its characteristics of relying on communication and decentralization of decision-making change the basis of modeling,making the traditional analysis and simulation methods no longer applicable.The research on distributed algorithm of smart distribution network needs a new set of theory and method support.The cyber-physical system can accurately model the complex system,and can be analyzed across multiple systems such as power and communication.By introducing this system,this paper proposes an analysis and evaluation method on distributed control strategy based on co-simulation for smart distribution network,and the corresponding co-simulation environment.Then,the distributed protection and control methods are studied in four typical cyber-physical coupling scenarios using this method.The performed fundamental research and the related innovative achievement in this thesis are summarized as follows:(1)The analysis and evaluation method for distributed control strategy and the design scheme of co-simulation environment.Considering the characteristics of smart distribution network,an analysis and evaluation method for distributed control strategy based on cyber-physical co-simulation is proposed.In order to solve the lack of support for distributed control simulation in current cyber-physical co-simulation,a co-simulation environment of distribution cyber-physical system Based on JADE is designed.This scheme not only studies the simulation details such as simulation framework,module connection and time synchronization,but also proposes a method to establish accurate controller model based on the performance evaluation of distributed controller.Using the co-simulation environment to analyze and evaluate the distributed fault location algorithm based on local anomaly factor,the implementation methods of model building,coupling point performance analysis and co-simulation evaluation are demonstrated.The results show the effectiveness of the proposed analysis and evaluation method and the cosimulation environment.(2)Application of differential protection in Ethernet passive optical network.By analyzing the differential protection algorithm of distribution network and Ethernet passive optical network,a differential protection method based on Ethernet passive optical network is proposed.The processing flow,server location selection and long distance communication scheme are deeply studied.Using the method of cyber-physical joint modeling,the feeder and Ethernet passive optical network models under short-circuit fault are constructed,and the influence of synchronization error and delay on differential protection is analyzed quantitatively.An Ethernet passive optical network communication system is designed for ieee-34 test feeders.Its electrical model and communication model are built in the co-simulation environment,and the effectiveness of the protection strategy is evaluated by co-simulation.The research results show that the differential protection algorithm can achieve fast and reliable fault location and isolation in Ethernet passive optical network through reasonable design.(3)Communication network and parameter optimization method for distributed feeder automation.The influence of communication mode,topology,communication protocol and data synchronization on current differential protection is analyzed in detail by using the method of cyber-physical system correlation analysis.A communication system scheme for distributed current differential protection is proposed.The interference model of communication system delay,data loss and communication jitter on distributed protection is established using the method of cyber-physical joint modeling,and the optimization method of communication parameters is studied.Referring to a real distribution line scenario,the corresponding protection and communication system is designed and built based on the co-simulation environment,and the performance evaluation and numerical analysis are carried out by co-simulation.Simulation results show that the proposed communication network scheme and parameter optimization method can effectively improve the reliability of current differential protection.(4)Distributed self-healing algorithm of distribution network based on auction theory.Based on the theory of multi-agent system,a distributed self-healing system of distribution network based on multi-agent technology is designed.The system structure,node control strategy and regional operation are studied in detail.A distributed selfhealing algorithm of distribution network based on auction theory is proposed.The autonomous control and negotiation method of agents are described through four steps of regional and global goal setting,resource identification,bidding and adjudication,so as to realize the rapid self-healing of distribution network.Based on an actual distribution line,a complete set of electrical,communication and controller models is built in the cosimulation environment.The game process and self-healing effect among agents are analyzed and evaluated by co-simulation.The simulation results show that the distributed self-healing algorithm based on the multi-agent system can quickly find the optimal reconstruction scheme and realize the power supply restoration in the largest area.(5)Application of distributed power flow control algorithm in smart metro power supply system.By modeling the energy flow of metro power supply system,the loss characteristics under different train operation modes are analyzed,and the optimal control objective of regenerative braking electric energy feedback is determined.The electric and communication network of Metro energy feedback system based on energy router is designed.The distributed control strategy of energy router based on parallel genetic algorithm is proposed.The system state confirmation,optimal control model and distributed optimization process are discussed in detail.The co-simulation environment is used to build a metro power supply and communication model including four energy routers and four metro vehicles to verify the effectiveness and real-time performance of the distributed control strategy.The simulation results show that the energy router based on distributed control strategy can reduce the loss of subway power supply network by36.7%,and has a good effect on improving the energy utilization rate of the system.This paper presents a distributed control strategy analysis and evaluation method,corresponding joint simulation environment,and distributed protection and control algorithm based on theory and co-simulation.On the one hand,the research results verify the effectiveness of the proposed distributed protection and control method,on the other hand,it also proves that the analysis and evaluation theory can analyze the complex system with deep coupling between power and communication,showing the advantages of the theory in the study of related complex systems,providing a new theoretical and methodological support for the research of smart distribution network.