Research On Track Circuit System Safety Analysis And Safety Early-warning

Track circuit is an important infrastructure of train operation control system, and its performance directly affects traffic safety and transport efficiency. At present, in the practical application of signal equipments, the failure rate of track circuit runs first, which not only causes train delays and affects transport efficiency, may also result in major accidents or loss of life and property.Present study carried out on RAMS of the track circuit isintended to address condition based maintenance, and improve system availability and reliability; There has been relatively lack of research on the safety analysis, relevant work has only focused on the qualitative analysis of single device level. But according to the requirements of system safety engineering, track circuit as a safety-critical system, the comprehensive and detailed safety analysis in its whole life cycle is very necessary to ensure the acceptable level of safety. Therefore, it is very meaningful to carry out the work of the track circuit system safety analysis to ensure the safety of the track circuit system radically. As the automation degree of current computer monitoring system in railway signaling is not high enough, it brings a lot work of browsing monitoring curve and data with low efficiency and accuracy, so the research on safety early-warning of the core system hazards is conducted to reduce the probability of occurrence of hazards effectively in order to protect the operation safety and improve operational efficiency.This paper carries out a comprehensive and detailed safety analysis on ZPW-2000A/K track circuit which is commonly used in high speed railway, and establishes its feasible and efficient safety early-warning system. The main research contents and research results are as follows:1) In accordance with the requirements of EN50126, the task summary of track circuit system, the system boundary and system environment, system functions and interface functions and performance requirements are defined, and assumptions and constraints of system safety analysis are derived; the system top-level hazards are obtained by FFA; and with reference to the THR allocation method in ETCS, the safety integrity requirements of CTCS-2on-board subsystem, trackside subsystem and transmission subsystem are derived.2) The track circuit system safety is analyzed in accordance with systemic risk analysis process of railway fields proposed in EN50129:FMECA method is adopted to verify and supplement the identified top-level risks, for each hazard the FTA is used to qualitatively and quantitatively analyze the causes and combination of the causes, the potential consequences of each hazard generated by ETA, a qualitative risk assessment is conducted based on risk matrix, the risk level of each hazards is also obtained.3) Based on the characteristics of the track circuit system and its safety analysis, early-warning indicators are proposed, and then the overall of the warning system is designed. A method for safety early-warning based on fuzzy comprehensive evaluation and asymmetric proximity is proposed, the early-warning indicators threshold calculation model is constructed; And the field data of Xinkaipu station in electricity department Changsha is used to validate this method, the results show that this method has higher the accuracy and good application value, the early-warning system can be used to forecast failures, unsafe condition and monitor performance deterioration process, it can reduce the labor intensity and has important practical significance to achieve the condition based maintenance.