传统的风险评估方法采用元素的长期故障模型和严重度指数,分别表征失效概率及其对系统的影响.在实际系统中,由于内部系统和外部环境的影响,故障概率具有时变特性.文中通过对系统中的每个严重性进行加权来形成严重性指数,并根据不同的重点,主观和假设的前提选择权重系数,提出了一种采用可信性度量来确定组件故障概率及全局模糊安全指数来衡量事故严重程度的新方法.选择N-1个突发事件作为级联失败的初始事件和风险等级,其应急分析的风险排序结果作为下一个模拟层的起始事件,以获得折叠序列.最后,文中模拟了RSTS六总线系统,得出的结果表明,所提出的方法更符合实际电力系统的运行状态.%In the traditional risk assessment method,the long-term failure model of element and severity indices are used to characterize the failure probability and its impact on the power system respectively.However,in the actual system,the failure probability has time-varying characteristic due to the influence of the internal system and the external environment.Severity indices are formed by weighting each severity in the system,and the weight coefficients are selected based on different focuses and with subjective and hypothetical premises.This paper introduces a novel assessment method which uses the credibility measure to establish the probability of component failure and global fuzzy security index to measure the severity of the accident.The N-1 contingencies are chosen as the initiating event of cascading failure and risk ranking.The results of risk ranking of the N-1 contingency analysis is regarded as the initiating event of the next simulation layer to obtain collapse sequences.As a case study,the RSTS six-bus system is simulated in the paper.The obtained results have shown that the proposed method is more more consistent with to the actual state of the power system.
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