基于ET-DFT分层模型的复杂系统动态概率安全评价方法研究

A Complex System Dynamic Probabilistic Safety Assessment Method Based on ET-DFT Hierarchical Model

为充分体现复杂系统的动态行为对其可靠性的影响,减少系统动态故障概率计算时的工作量,应用层次化分析思想,综合事件树(ET)和动态故障树(DFT),提出基于ET-DFT模型的动态概率安全评价(DPSA)方法。应用二元决策图(BDD)和马尔科夫链(MC)分别对静态故障树和DFT进行求解,给出将静态故障树和DFT向BDD及马尔科夫链转移图的转化算法,以及系统各状态概率的求解方法。通过应用实例的分析验证,得到系统静态模块定量的发生概率及动态模块各个状态概率随时间变化的曲线,经综合求解得到系统故障发生的概率,实现对系统较为精确的DPSA。

In order to fully consider the influence of complex systems＇dynamic behavior on their reliability, and to reduce the system dynamic failure probability calculation workload, a DPSA method based on ET-DFT model was worked out by integrating ET and DFT, where the hierarchical analysis method was used. The BDD and MC were used to solve the static fault tree and DFF. The transformation algorithms between static fault tree and BDD, and between DFT and MC transform diagram were presented. A solu- tion method of each state probability of the system was also given. A certain application example was used to illustrate the proposed method. It shows that the quantitative occurrence probability of system static module and the probability of each state change over time of system dynamic module can be obtained, and the system fault probability can be obtained through comprehensive solution. The accurate dynamic probabilistic safety assessment of the system can be realized.