带变权的电力变压器状态模糊综合评判

Fuzzy Synthetic Evaluation of Power Transformer Condition with Variable Weights

针对常权无法客观反映电力变压器部分参数偏离正常值时对整体评估影响的不足,提出了带变权的状态综合模糊评判方法。通过分析影响变压器状态主要方面的特征参量,建立了层次型评估指标体系;在用层次分析法确定指标常权的基础上,引入了基于均衡函数的变权模式,综合考虑指标间的均衡性,并根据实际数据偏离正常值的大小,对常权修正得到变权;最后利用模糊理论确定单因素对各状态等级的隶属度,并基于多级模糊评判的思想分别对各层进行评判,综合得出了变压器状态。用实例比较变权与常权模糊评判的结果表明,应用基于均衡函数的变权综合比常权更合理、客观,其评判结论更接近变压器真实的运行状态。

Aiming at the deficiency that constant weight is unable to objectively reflect the impact of the deviation of some parameters, a fuzzy synthetic evaluation method with variable weights for condition of power transformers was introduced. Through analyzing the state variables affecting main facts of operation condition, a layered evaluation indices system for transformer condition assessment was built. First, the AHP method was used to determine the constant weight of every indices, then the variable weight model was introduced based on balanced function, in which the constant weights was modified to get the variable weights, according to the deviation of actual data and normal state. Then the fuzzy set theory was applied to determine the membership degree of a single index, and based on the idea of mufti-grade fuzzy evaluation, the condition of every grade was valuated to get the comprehensive status of power transformers. By comparing the fuzzy synthetic evaluation based on constant weights with that based on variable weighs, the example showed that, the condition assessment for power transformers using variable weights based on balanced function is more reasonable and more objective, and the valuation conclusion was also more close to the actual condition of transformer.