随着用户对供电质量要求的提高，配电系统的可靠性评价问题也越来越受到人们的重视。在分析配电系统可靠性问题的基础上，提出了配电系统可靠性评价的可变模糊方法。该方法首先根据指标特征值、指标评价区间矩阵、可变范围评价区间矩阵及点值矩阵确定相对隶属度矩阵，然后利用可变模糊评价模型对样本进行综合评价，得到样本在各级别下的综合相对隶属度，进而计算级别特征值，并以此为依据进行评价。可变模糊方法可以科学地确定样本指标对各级指标标准区间的相对隶属度，并且能够通过变化模型及其参数，合理地确定出样本的评价等级，提高对样本等级评价的可靠度。通过对某地区配电系统进行评价，得出其级别特征值比较稳定，总体评价结果为合格。结果表明，可变模糊评价方法可靠，可用于配电系统可靠性评价。

The reliability evaluation of the distribution system becomes more and more important due to the customer's requirement for a distribution system of a higher quality. Based on the analysis of reliability for distribution systems, a variable fuzzy method is proposed. Firstly the matrix of relative membership degree is calculated based on the index feature value, the matrix of index evaluation interval, the matrix of variable range evaluation interval and the matrix of point values. Then the comprehensive relative membership degree of samples is calculated by a model of variable fuzzy evaluation. The rank feature value is thus obtained, for the evaluation. The variable fuzzy engineering method can scientifically determine the relative membership degrees of sample's indexes at level intervals, and reasonably determine the evaluation level of each sample by varying the model and its parameters. From the evaluation of the reliability of the distribution system, a relative stable value can be obtained to be regarded as the final evaluation. The case study shows that the method gives more reliable evaluation of reliability of a distribution system than the method in literature.