Modeling And Reliability Evaluation Of Cyber Physical Distribution System

Distribution system intelligence is a very important part of smart grid construction.As the scale of the grid continues to expand,smart city construction and distributed power supply access have higher and higher requirements for distribution system intelligence.The realization of distribution system intelligence requires the support of information and communication technology to achieve fast fault location,isolation,and service restoration(FLISR).In the FLISR process,the frequent interaction between the communication network and the distribution network makes them form a typical architecture consisting of a cyber system and a physical system,i.e.Cyber-Physical Distribution System(CPDS).The modeling of CPDS helps to simulate the intelligent process of the distribution systems more objectively and scientifically and provides theoretical support for the construction of the distribution system.It is important to evaluate the reliability of CPDS and analyze the factors influencing the reliability of CPDS for system optimization.However,CPDS modeling and reliability assessment still face some challenges,mainly focusing on the inability of conventional CPDS models to intuitively reflect the cyber-physical interaction process and the low efficiency of reliability assessment.This paper uses this as an entry point to conduct research.First,the distribution physical system model and the distribution cyber system model are constructed.The distribution physical system model includes distributed power supply model,time-series load model,and physical component sampling model,which can simulate the real state of distributed power supply,load,and physical components.The distribution cyber system model includes the information channel availability model and the Intelligent Electronic Device(IED)model.The information channel time delay sampling method is optimized,which can improve the efficiency of the distribution cyber system state evaluation.Then,the FLISR process model is constructed to portray the FLISR process of distribution system through physical state matrix,information transmission state matrix,control transmission state matrix,fault information matrix,control command matrix,and IED action matrix and their interactions and effects,and then obtain the outage time matrix and fault isolation interval,which can reflect the cyber-physical interaction mechanism more clearly and provide a basis for CPDS reliability assessment.Finally,the CPDS reliability assessment method is proposed,and different CPDS reliability assessment models are constructed according to different structural distribution network FLISR processes to improve the generalizability of the CPDS reliability assessment method.In this paper,simulation analysis of the evaluation efficiency of the information channel availability model is carried out,and the simulation results show that the model can achieve fast and accurate simulation of information channel reliability,which can improve the accuracy and speed of CPDS reliability evaluation.The simulation analysis of the influence of different distribution network structures,different information components,and different information network structures on CPDS reliability is carried out,and the results reveal the key elements to guarantee and improve CPDS reliability,which can provide valuable reference and basis for distribution network planning and distribution network reliability optimization.