利用二元决策图求解故障树的基本事件排序

Basic event ordering in fault tree analyses using binary decision diagram

故障树分析是一种核电站常用的概率安全评价方法。对利用二元决策图求解故障树方法中的关键问题——基本事件排序进行了研究。先将故障树转化成二元决策图,然后通过遍历二元决策图直接获取割集。在转化的过程中,基本事件的排序对二元决策图的规模和计算速度有着直接的影响。寻找基本事件的最优排序是该方法的重点。该文提出的三条排序法则,对基本事件的排序有明显的帮助,可使二元决策图结点数减少约二分之一。

Fault Tree Analysis （FTA） is widely used to analyze system reliability. This paper describes the use of the Binary Decision Diagram （BDD） for FTA and the ordering of the basic events. The Fault Tree is first transformed to a BDD, and then cut sets are directly obtained. The ordering of the basic events is crucial to the size of the resulting BDD and the analysis speed, so the optimal ordering is a key part of the analysis. Ordering rules presented applicable for most FTA cases can reduce the number of BDD nodes by almost half.