The Vulnerability Analysis Of Integrated Energy System Based On Dependency Characteristics

With the development of economy and society and the improvement of people’s living standard,the traditional single energy supply method can hardly meet the diversified energy demand,thus leading to the problem of imbalance between energy supply and demand in many countries and regions.The proposed integrated energy system can realize the efficient distribution and transformation of energy and improve the efficiency of energy utilization.However,integrated energy systems contain multiple energy sources,multiple energy conversion methods and multiple devices,and their system structures are relatively complex.In order to better analyze the operation of the integrated energy system,discover the problems in the system,and take corresponding measures to improve the reliability and stability of the system,this paper studies the vulnerability of the integrated energy system.Firstly,the basic structure and dependency characteristics of the integrated energy system are studied,the structural characteristics of the system are analyzed,the general conversion model and typical energy conversion equipment model are comprehensively sorted out and summarized,the system dependency relationships are classified into four types:physical,information,geographical and logical,and then the dependency concept diagram of the integrated energy system is constructed,which lays a theoretical foundation for the comprehensive vulnerability analysis of the system.Secondly,for the energy subsystem,a system vulnerability analysis method based on dynamic fault tree and continuous time Bayesian network is proposed to establish a more accurate and complete system failure model,effectively capture the fault propagation dynamics within the system,and calculate the probability of failure caused by the energy subsystem.The interdependence network of the integrated energy system is then constructed based on the dependency concept diagram of the integrated energy system and based on the four dependency relationships.A simulation-based approach is proposed to calculate the integrated failure probability of the system to realize the integrated vulnerability analysis of the integrated energy system.In order to verify the effectiveness of the proposed integrated vulnerability analysis method for integrated energy systems,an integrated energy system consisting of electric power subsystem,natural gas subsystem,and thermal subsystem is used as a test case to calculate the probability of failure within the subsystem,the probability of failure between the subsystems,and the integrated probability of failure within and between the subsystems.The analysis results of the cases verify the universality of the proposed vulnerability analysis method for integrated energy systems based on the dependency characteristics,and enable accurate quantitative analysis of the vulnerability of integrated energy systems.