中文摘要：

敏感设备电压暂降故障水平评估的最大困难在于各影响因素的不确定性和评估建模。根据相关因素的内涵和外延不确定特征，对电压暂降强度、设备电压耐受能力、设备故障状态的不确定性进行研究，建立相应的数学模型。在此基础上，基于模糊安全事件隶属函数的建立原则与模糊事件概率计算模型，构建能同时反映各影响因素不确定性的敏感设备电压暂降故障水平评估模型，并对相应算法和评估过程进行较详细的研究。对个人计算机进行评估，结果证明该方法的正确性和可行性，该方法不需专家经验或主观假设，能客观地反映实际情况，并可方便地推广应用于相关领域。

英文摘要：

The greatest difficulty for the evaluation of sensitive equipment failure level caused by voltage sag lies in the uncertainties of influencing factors and the method of modeling assessment. In order to evaluate the failure probability of equipment caused by voltage sag, the uncertain properties of voltage sag severity, voltage tolerance of equipment and the running state of equipment were studied based on the uncertainty of intension and extension. The uncertain models of influencing factors were established. The evaluation model for failure probability of equipment was established and its algorithms and assessment process were studied, using the determination principle of fuzzy membership function of the fuzzy safety event and the probability computation model of the fuzzy event. This method considers the multi-uncertainty of influencing factors of equipment failure level caused by voltage sag at the same time. Simulation studies have been carried out in the personal computer. The results show this method is correct and viable, and it can be conveniently applied in other related areas, not demanding any expert experience or subjective hypotheses.