Reliability Evaluation Method Of Micro-energy Grid Cyber-physical System

The micro-energy grid is an extension of the microgrid,coupling and coordinating the supply of electricity,cold(heat),gas and other energy sources.As an independent subsystem of the integrated energy system and the physical carrier of the energy internet,the microenergy grid is a typical system of cyber-physical integration.The control and operation of the micro-energy grid depend on information feedback and decision-making,and the coupling relationship between cyber networks and energy networks is becoming more and more complex,which brings new challenges to the reliability evaluation and vulnerability analysis of the micro-energy grid cyber-physical system.The thesis takes the micro-energy grid under the background of CPS as the research object,and carries out the following aspects of research:(1)Given the failure of the traditional single evaluation index to comprehensively and quantitatively evaluate the reliability of micro-energy grid cyber-physical system,this thesis established the reliability evaluation index of micro-energy grid cyber-physical system by combining energy entropy and information entropy theory,and proposed a reliability evaluation method based on random matrix theory.The reliability evaluation model is established by random matrix theory,and the abnormal state of the system is identified by analyzing the statistical characteristics of the matrix,which avoids the factors such as the difficulty in accurate modeling of the distribution system and the limitation of data utilization.Finally,the rationality and effectiveness of the proposed index and method are verified by arithmetic cases.(2)To address the vulnerability evaluation of micro-energy grid CPS under cyber-attack,a suitable vulnerability evaluation index for micro-energy grid CPS is established,and a coupled model of micro-energy grid cyber-physical system is constructed and analyzed for its vulnerability.The weighted line betweenness and the weighted node betweenness are introduced to formulate corresponding attack methods to attack the micro-energy grid cyber physical system.The vulnerability evaluation index of node loss ratio and load loss ratio are established,which can overcome the limitations of traditional indexes and effectively identify the impact of nodes and branches on system vulnerability.Finally,the proposed index and model can effectively analyze the vulnerability change law of the micro-energy grid through arithmetic cases.(3)To address the problem of increased security risk of the interaction between cyberphysical systems after cyber-attack on micro-energy network information systems,an electric-gas coupled cyber-physical system-based model is constructed,and a system reliability reliability method under cyber-attack is proposed.On this basis,a multi-timescale reliability enhancement strategy for branch power and pipeline flow optimization of the cyber-physical system of electric-gas coupled micro-energy networks considering false data injection attacks is proposed.The proposed optimization strategy reduces the overrun range of transmission lines and natural gas pipelines,reduces the probability of cascade failures in the system under cyber attacks,and improves the system’s resistance to cyber attacks and the reliability of energy supply.