Research On Dynamic Risk Analysis And Evaluation Method For High Speed Train Traction System

The traction system is the core system for powering high-speed trains.If its safety cannot be effectively guaranteed,the safety of passengers and vehicles will always be threatened.In actual operation,high-speed train traction system failures frequently occur,which will lead to high-speed train speed reduction,stopping,and even may lead to personal injury and other adverse consequences.These faults are often evolved from other small anomalies or fault propagation.If the propagation evolution path can be cut off effectively and timely,negative consequences events can be avoided.Therefore,it is very important to study the dynamic risk assessment method of high-speed train traction system.Taking the CRH2 high-speed train traction system as an example,a comprehensive fault mode analysis and risk ranking was carried out,and two fault modes with higher risk order number were obtained.Using Matlab/Simulink to simulate and analyze the fault mechanism,considering the risk characteristics such as IGBT junction temperature rise,combined with the actual operation of high-speed train and operation and maintenance factors,the dynamic risk assessment is carried out,and the obtained risk analysis results are more realistic.Firstly,in this thesis,taking the CRH2 high-speed train traction system as an example,the distribution of each component in each compartment and its working principle based on its circuit topology are introduced.The technical characteristics,working principle and technical parameters of traction transformer,traction converter and traction motor are introduced,which provides a basis for subsequent FMEA analysis and modeling.Secondly,in order to understand the fault condition of the traction system as comprehensively as possible,this thesis combines the introduction of the structure of the traction system of CRH2 high-speed train,draws its structural level block diagram,and uses the FMEA hardware method to analyze the risk from the structure.In the analysis,the typical 17 failure modes are listed,and their fault causes are dug into,and fault effects and compensation are measured.Through the ordering of the number of dangerous sequences,the weak links in the traction system are obtained and operational and maintenance aspects are proposed.The static risk analysis assessment based on FMEA laid the foundation for dynamic risk analysis assessment.Thirdly,in this thesis,Matlab/Simulink is used to model and simulate the CRH2 high-speed train traction system,focusing on the SVPWM control mode and simulation model of the three-level inverter.At the same time of simulating the normal operating conditions,this thesis also selects the IGBT single-tube open-circuit fault,the small gain of the speed sensor,and the composite fault of the two,as an example,and obtain the traction inverter output when the fault is respectively obtained.The waveforms of voltage,traction motor stator current,electromagnetic torque and speed are compared with normal waveforms.The mechanism of the above faults and the process of propagation evolution are analyzed,which provides a basis for dynamic risk consequence analysis.Finally,in this thesis a dynamic risk analysis method for high-speed train traction system based on feature quantity is proposed.Taking the fault chain of "CRH2 high-speed train traction system composite fault" as an example,combined with the previous fault mechanism and propagation evolution analysis,establish mathematics model.Based on the experimental data and relevant national standards,the mathematical relationship between the composite fault feature quantity and the traction motor failure rate is obtained,and the probability of dynamic composite risk chain occurrence is obtained.The event tree method and gray clustering method are used to analyze the consequences of the composite risk.At last,taking the actual "Chengdu-Chongqing Passenger Dedicated Line" as an example,the risk analysis and evaluation of the specific trains were carried out to verify the feasibility of the method.Through the above research and analysis,this thesis provides theoretical support for reducing the risk of high-speed train traction system,improving the safety of personnel and transportation operation and maintenance,and has important practical significance.