Study On Modeling Business Importance And Business Reliability Of Grid Cyber Physical System

With the developing level of informatization and digitization,the influence between information flow and power flow has been more frequent in smart grid.Smart grid is a typical cyber physical system(CPS).The concept of GCPS(Grid Cyber Physical System)is put forward to reflect the global operation of physical and information process in smart grid,and highlight the mechanism of fusion and interaction.By using more advanced control methods,it can improve energy efficiency,equipment potential and safety,stability and reliability of power system.The purpose of GCPS is to promote the system performance and optimize the whole system operation.However,the uncertainty and complexity of heterogeneous network bring new uncertain factors to GCPS.With the increasing dependence on the information network in GCPS,the cyber attack or failure of information system will affect the reliable operation of the power grid.The system modeling and safety and reliability research of GCPS are the problems to be solved at present.Firstly,the hierarchical model of GCPS is established in this paper.This model has five layers,which are information equipment layer,communication subnet layer,network layer,information business layer and physical system layer.According to the flow characteristics of information in the model,the vertical structure and horizontal structure model of layer relationship are put forward.Considering the importance of power business,the vertical structure and horizontal structure model of information business layer are established.These models are the basic work of the follow-up research.Secondly,considering the hierarchical model,the evaluation model of business importance based on the requirement of communication performance is established.The evaluation model takes the evaluation indexes of communication performance and the relevance model of business data flows into account,which can evaluate business importance comprehensively.Business importance is the influence factor of system risk management and safety protection.Taking the evaluation of business in production and control area as an example,the evaluation results conform to the actual operation situation and verify the correctness and objectivity of this model.Lastly,the analysis model of business reliability considering the cyber attack factor is established,which combines the relationship within business layer and between business layer and others.Based on the selection of cyber attack factors in CPS,the evaluation indexes of information equipment considering attack factor and business factor is put forward.Then the evaluation model of business reliability is established with information equipment associated.The model combines the analytic hierarchy process and the Bayesian network method to calculate the business availability.Business availability is one of the factors influencing the reliability analysis of power system in GCPS.Taking the reliability evaluation of wide-area control business as an example,the result shows that the proposed method in this paper is practicable and reasonable.It provides reference for reliability analysis of GCPS.