敏感设备电压暂降失效率区间最大混合熵评估

Estimation of maximum interval hybrid entropy of sensitive equipment failure rate due to voltage sag

考虑设备故障状态的过渡过程,将正常和完全故障以外的状态归结为不完全故障状态,对设备在电压暂降作用下发生失效的可能性进行了评估。首先通过区间数刻画敏感设备电压耐受能力,结合供电端暂降发生的随机性,确定电压暂降作用下设备可能发生的非正常状态概率区间。为更全面考虑实际存在的复杂不确定性,利用混合熵能综合考虑供电端电压暂降的随机性和模糊性的特点,建立区间概率最大混合熵模型,在给定约束条件下识别满足熵值最大原理的分布,作为设备敏感度的评估测度,以此得到设备失效率的点值评估结果。利用实测PC机电压暂降失效率数据进行对比,发现在小样本情况下得到的结果能达到相当高的精度。最后以33节点配电网为例进行仿真,证明方法的正确性。

According to the transition process of equipment fault status ,all kinds of status excluding normal and complete fault status are considered as incomplete fault status and the possibility of equipment failure due to voltage sag is evaluated. The voltage tolerance level of sensitive equipment is characterized by the interval data and,combined with the randomness of voltage sag,the interval possibility of incomplete fault status is determined. To more comprehensively take the complexity and uncertainty into account,the hybrid entropy is used to measure the randomness and fuzziness of practical voltage sag and the model of maximum interval hybrid entropy is developed to estimate the equipment sensitivity under certain conditions and to obtain the point probability of equipment failure rate. Comparison with the measured data of personal computer failure rate due to voltage sag shows that ,the results in small samples are quite accurate. The simulation for IEEE 33-bus system proves the effectiveness of the introduced method.