一种电力系统连锁故障的概率风险评估方法

讨论了连锁故障风险评估的框架结构，即确定元件停运模型、选择初始系统状态、相继故障过程分析和风险计算。该文在分析中考虑了保护误动、断路器拒动、元件组停运、电站相关停运、共因停运等相关停运模型，利用功能组分解技术和事件树分析法，选择连锁故障的初始系统状态，提出简化相继故障过程分析的依据和处理方法，进而提出一种新的连锁故障概率风险评价方法。通过算例，给出不同停运模式的风险指标以及系统元件的风险排序。仿真结果显示，系统发生连锁故障的总风险值随负荷率的增长而增长。当负荷率小于1时，连锁故障总风险主要由保护误动模式承担；当负荷率达到1和1.26两个临界点时，总风险发生两次突变。其中，第1个临界点受共因停运模式的影响，第2个临界点受单元件强迫停运模式的影响。

A Probabilistic Risk Assessment Method for Cascading Failure of Power System

The article discussed frame structure of risk assessment for cascading failure, namely decision of component outage model, choice of initial system state, analysis of continual fault process, and risk computation. Besides protection maloperation model, this paper thought over other dependent outage models such as stuck breaker, component-group outage, station-originated outage and common cause outage; the article chose initial system state of cascading failure by using of function group decomposition technique and event tree analysis, provided simplification principle and processing method of continual fault process analysis, then proposed one new probabilistic risk assessment method for cascading failure. Through the example, the article provided risk index of component outage models and risk ranking of system components. The simulation demonstrated that, the total risk value of cascading failure grows along with load factor growth. When load factor is smaller than 1, the total risk of cascading failure is mainly undertaken by protection maloperation model; when load factor achieved critical points of 1 and 1.262, the total risk value has two times of sudden changes. The first critical point is affected by common cause outage, the second critical point is affected by single component forced outage.