Research On Dynamic Risk Analysis And Evaluation Method Of Metro Power Supply System

With the rapid development of the city and the increasing demand for travel,the metro has developed rapidly as a high-volume,high-efficiency vehicle.The main traction power of the metro train comes from the power supply system.Whether the state of the metro power supply system is stable will affect the stability of the operation of the railway network.Therefore,the risk level of the metro power supply system has received widespread attention in recent years.Studying the risk analysis and evaluation method of the metro power supply system has a very positive significance for the operation and development of the metro.In this thesis,the modeling and simulation of the metro power supply system is used to understand the operation and failure mechanism of the metro power supply system.The combination of static risk assessment and dynamic risk assessment is used to comprehensively consider the various equipments of the system and discover the weak links of the system.Moreover,the research on the risk characteristics of the system along the risk chain propagation process is carried out,and the impact of the operation status of the power supply system on the passenger flow of the railway network is considered,so that the dynamic risk level of the metro power supply system can be more comprehensively understood.Dynamic risk research can detect systemic risk bottlenecks and risk sprouts early,and help to take timely security measures to keep system risk levels within safe limits.Firstly,a model of a relatively complete metro power supply system is established by understanding the structure and various components of the metro power supply system.The mechanism simulation of the normal and fault conditions of the metro power supply system is carried out to understand the changes of the relevant electrical quantities in the system,which provides a basis for subsequent risk analysis and evaluation.Secondly,the failure mode and effects analysis is combined with the fault tree method.The failure mode and effects analysis table of the metro power supply system is listed,and the 1500V power failure fault tree model of the metro power supply system is established.Through the analysis,the risk level of each basic event in the system is obtained,and the weak links are found,which provides support for further dynamic risk analysis and evaluation.At last,the dynamic risk assessment of the DC cable breakdown risk chain of the subway power supply system is carried out.In this thesis,the probability of DC cable breakdown in metro power supply system is obtained by fuzzy reasoning.The knowledge of graph theory is used to obtain the severity of the consequences caused by DC cable breakdown on the railway network.The probability level can be combined with the severity of the consequences to analyze the risk level.This thesis proposes preventive and control measures for the risk assessment results to ensure the normal operation of the railway network.