Study On The Reliability And Safety Of ZPW-2000A Track Circuit

The operation of Chinese high-speed railway can't be separated from the reliable and safe working of its subsystems.As the core of railway operation,railway signaling system plays an important role for the effective,stable and safe operation of high-speed railway.ZPW-2000A track circuit,which performs as the critical equipment of railway signaling system,is widely used in Chinese Train Control System-2/3,the stable and continuous working capacity of the equipment is a key guarantee for the efficiency of railway transportation and the safety of the passengers' life and property.The track circuit faults account for a relatively large proportion in railway accident causes under the application of railway field.Therefore,it can be of great significance and provide practical application value to research on the reliability and safety of ZPW-2000A track circuit.According to the structure and function of ZPW-2000A track circuit,the reliability for system equipment layer is analyzed from different aspects,then associates with the filed accidents or equipment failure,a safety analysis on track circuit viewed from system potential hazard layer is obtained.Specific research work and results are as follows:Firstly,based on the detailed analysis for system units and its functions,reliability block diagram of track circuit is conducted.Next,fault tree analysis model of track circuit considering single set of equipment and redundancy equipment are established,then reliability indexes are conducted by qualitative and quantitative analysis,and the influence of redundancy structure on system reliability is obtained by comparative analysis.Further efforts focus on system environment considering common cause failure(CCF)in detail,the change of reliability indexes of track circuit redundancy system considering CCF are observed by using ?-factor model,so,the influence of CCF on the system is evaluated quantitatively.Secondly,on the background of a large number of units in track circuit and the complexity of reliability analysis,an auto-solve program for minimum cut set(MCS)is designed based on Xamarin Studio and the system reliability simulation program based on MCS is written by MATLAB and Monte Carlo algorithm.Furthermore,the "N+1"redundancy of transmitter and the section compensation capacitors are considered into the reliability simulation of a complex track circuit system composed of nearly 30 basic units.The simulation results obtain the MTTF index,unit importance,and the weakness of system.Thirdly,based on the railway accident or fault causing by track circuit,the research extends from the system mechanical layer to the potential hazards one.According to the risk assessment process described in EN 50129,part of the top potential hazards is identified,and its risk category is determined by risk matrix method.Furthermore,through establishing safety analysis model for typical top potential hazards based on Bayesian network,underlying risks are found from top to bottom,and its posterior probability are quantitatively obtained.Next,all risks are classified,and the possible approaches causing the occurrence of potential hazards are quantitatively analyzed in multiple angles.Finally,referring to the results of quantitative analysis,the improvement measures for the safety of ZPW-2000A track circuit are put forward.