Modeling And Simulation Of Process-level Network And Relay Protection In Intelligent Substation

The application of digital communication network,electronic transformer and intelligent electronic device in smart grid greatly simplifies the structure of the power secondary system.At the same time,it also introduces many uncertainties.The power information system(secondary system)and physical system(primary system)belong to discrete event system and continuous system respectively.Their modeling form is quite different.So far,there is no integrated simulation software based on unified modeling of power information and physical system.Some researches integrate special power system simulation software and information system simulation software to build a hybrid simulation environment,but it is difficult to solve the problem about timeliness and accuracy of information interaction among different software.To study the influence of the information system on the physical system is greatly significant to the development of the smart grid.Discrete event system specification(DEVS)provides a standard hierarchical modular framework for the simulation modeling of discrete event system,continuous system and hybrid system.Using DEVS can establish unified and standard simulation model to describe the dynamic process of power information system and physical system,and realize the timely and accurate interaction between the power information and the physical simulation process.It is a feasible method to construct the simulation environment of electric information and physical integration.Smart substation is an important part of the smart grid.In this paper,we take the intelligent substation process layer network and relay protection system as the object,researching the technology of building DEVS simulation models for the corresponding components and systems.The main research context is as follows:(1)The intelligent substation architecture based on the IEC61850 specification is introduced.(2)The theory and technology of DEVS modeling are analyzed.The program library DEVS++ which realize the simulation of DEVS model are introduced.(3)The DEVS models of substation process layer communication equipment(switcher,hub,channel,data link layer transmitter and receiver)and network are built.The information transmission delay of process layer is simulated.(4)The DEVS models of intelligent electronic devices(electronic transformer,merging unit,intelligent terminal,distance protection)and power physical systems are built.Together with the process layer network model,a hybrid model of physical and information of intelligent substation is established.The simulation tests verify the correctness of the model.