Cascading failures can occur in many technical systems where the components are organized as in series–parallel structures. The failures in these systems may propagate from one component to the other, not only within the same parallel sub-structure but also between different sub-structures. This article presents a recursive aggregation method based on the extended models of reliability block diagram, for analyzing the impacts of cascading failures on the reliability of series–parallel systems. Based on the reliability analysis, the effects of safety barriers on preventing cascading failures are studied, and the importance of safety barriers at different locations is evaluated. One simple example of three components and one practical case from an oil production system are presented. The findings in these case studies illustrate how system designers and safety managers can identify the effective and reasonable ways of installing safety barriers by using the proposed approaches, for the mitigation of cascading failures in series–parallel technical systems.

级联故障可能发生在许多技术系统中，这些系统中的组件以串联-并联结构的形式组织。这些系统中的故障可能会从一个组件传播到另一个组件，不仅在同一并行子结构内，而且在不同子结构之间。本文提出了一种基于可靠性框图扩展模型的递归聚合方法，用于分析级联故障对串并联系统可靠性的影响。基于可靠性分析，研究了安全栅对防止级联故障的影响，并评估了安全栅在不同位置的重要性。提出了一个由三个组成部分组成的简单示例，一个来自石油生产系统的实际案例。