Subsequently, the grade diffusing process was described combining with the failure pervasion intensity, and the failure propagation paths and relevant key nodes with high pervasion ability were found with the ant colony algorithm.

• 结合故障的扩散强度，按照分步扩散的原则对故障传播的过程进行了描述，同时用蚁群算法求得扩散能力最强的故障传播路径及相应的关键节点。