Research On Safety Of Shunting Train Protection System Based On System Safety Risk Theory

Shunting Train Protection System is a control system developed to ensure the safety of shunting operations within the station and to improve the automation of shunting operations.STP system has complex structure and functions,high integration of hardware and software and strict safety requirements.Compared with the traditional railway signal system,STP system has been put into use for a short period of time and has not yet been fully analyzed using system safety assurance technology based on modern system safety engineering.This paper begins with the safety related functions of STP system,using system safety risk theory and method,carrying out hazard identification,risk analysis and risk control of STP system safety related functions in turn,and realizes functional safety analysis of STP system.According to relevant standards and technical data of STP system,the paper comprehensively analyzes the composition,principle and basic functions of STP system.Then the paper completes the analysis of needs of the two important safety related functions of initial positioning and vehicle tracking as well as overspeed protection of STP system,which provides a basis for subsequent hazard identification.The common methods of hazard identification are summarized and analyzed.According to the features of STP system,the identification method of functional hazards based on FMEA is selected.Taking the two main functions of STP system initial positioning and vehicle tracking as well as overspeed protection,twelve related sub-functions and two communication interfaces as examples,the FMEA analysis is performed from the three aspects of failure mode,fault cause and fault influence,which provides the basis for subsequent risks analysis.The risk analysis methods are summarized and analyzed.Based on the functional safety analysis of STP system,the risk analysis method based on the risk matrix is selected.Due to the subjective and fuzzy uncertainty of expert judgments,the theory of fuzzy sets is introduced to convert the qualitative evaluation of experts into the quantitative calculation of fuzzy numbers.Using fuzzy risk matrix method to carry on the risk analysis of STP system function hazrd,using fuzzy comprehensive evaluation method to carry on the risk analysis to STP system function and the interface.The results of risk analysis can prove the safety of STP system.The risk control methods are analyzed and the risk control process as well as options decision method are studied.This paper analyzes the options of risk control measures for four hazard that need to reduce the risk level for the two main functions of initial positioning and vehicle tracking as well as overspeed protection of STP system.Finally,the paper provides feasible risk control measures in terms of hardware,software and system functions.The paper first uses system safety risk theory to carry out safety analysis on STP system,which has great significance for ensuring the safety of STP system.