基于事故树分析的铁路牵引供电系统可靠性评价

提出一种基于事故树分析的可靠性评价方法,用于描述电气化铁路牵引供电系统各失效原因之间的逻辑关系,并通过定量分析方法计算系统失效概率函数。虽然事故树分析方法被用于评价复杂大系统的可靠性时具有良好效果,但不足之处是需要消耗大量的计算时间。因此,本文又进一步提出一种事故树近似评价方法,根据串-并联和并-串联系统的可靠性函数计算事故树顶事件发生概率的上、下边界,然后计算上、下边界的平均值作为事故树顶事件发生概率的近似值。本文以电气化铁路交流牵引供电系统AT供电方式为例建立事故树,并应用本文提出的近似方法对该算例事故树顶事件发生概率进行计算,证明本文方法与传统的准确评价方法的计算结果之间误差很小,且较大程度减少了评价过程所需的计算时间。

Reliability Evaluation of Railway Traction Power Systems by Fault Tree Analysis

A reliability evaluation method by fault tree analysis is presented.It depicts the logical relationships among failure factors of railway traction power systems and calculates their failure probability with the quantitative method.Fault Tree analysis is well applied in the evaluation of a large and complex system,however,it appears to have a disadvantage of much time consumption.So,an approximate evaluation method by fault tree analysis is presented.The upper bounds and lower bounds of the occurrence probability of top events in fault trees are calculated according to the reliability functions of both a series-parallel system and a parallel-series system.An approximate occurrence probability is obtained through computing the mean values of the upper bounds and lower bounds.Finally,the occurrence probability of top events of the fault tree is calculated with the proposed approximate evaluation method by example of the established fault tree of an AC traction power supply system of an electrified railway.The result shows that the proposed method has small errors ascompared with the traditional method and it saves the calculation time for evaluation to a comparatively great degree.