DFT's Application In Reliability Analysis Of Automatic Train Supervision System In Subway

With the development of modern society and the improvement of living standards, public transport safety has been taken more and more attention from the government, community and general public. As an important part of the public transport, the safety and stable operation of metro also appears to be particularly important. The Automatic Train Supervision system which is a component of the signaling system plays an important part in guaranteeing safety and punctually operation of the trains.The structure and function of Automatic Train Supervision system were introduced in the paper, considering ATS system with the characteristics of fault-tolerant, order-related and redundant, reliability block diagram which is always used in system Reliability analysis, the paper discuss the disadvantages of reliability block diagram using in reliability analysis, so dynamic fault tree analysis has been put forward to analyze the Automatic Train Supervision system. Dynamic fault tree analysis is developed by introducing the dynamic logic gate on the basis of the traditional fault tree analysis, which can performance the feature of fault-tolerance, order-relative and redundancy of the system.According to the demand of reliability analysis for ATS system, we bring forward life expectancy as indicator of Reliability analysis, and indicate EBDD method and EMC method, By which life expectancy can be determined, which provides approach to reliability analysis of ATS system.Take the example of Beijing subway No.2 line ATS system, we propose processe of application, then calculate the results according to the processes, after that we analyse the results and raise some corresponding maintenance proposals, shows that DFT is more appropriate comparing to block diagram.At last, we present software framework of dynamic fault tree analysis. It contains the functions of designing trees and Qualitative and quantitative analyzing which can provide computer-aided decision support for metro trains automatic supervision.