基于矩估计法和模糊—证据融合的电力变压器套管状态评估

Condition assessment of power transformer bussing based on moments estimator and fuzzy evidence combination method

基于模糊数学和证据理论,提出了一种变压器套管状态评估模型。该模型以套管试验数据为基础并结合巡检项目,从定性与定量角度构建层次评估指标体系;考虑到目前变压器状态评估中单一赋权方法存在的局限性,引入矩估计法建立主客观权重的最小偏差函数从而得到最优组合赋权。同时针对状态参量的模糊性、不确定性,采用模糊评判法获得原始信度分配并对其修正,最后结合改进融合规则对套管状态等级进行评估。实例验证表明,此评估方法准确有效。

On the basis of the fuzzy mathematics theory and the evidence theory,an assessment model of bushing con-dition of transformers is proposed in this paper.Firstly,the hierarchical evaluation index system is constructed from the perspectives of qualitative and quantitative,which is based on experimental data and also considering the inspec-tion tour program.Then,considering the shortages of single weighting in transformer condition assessment,this paper introduces a method to obtain the optimal weight.The subjctive and objective factors are combined through solving the minimum deviation optimal function.Meanwhile,for the fuaziness and uncertainty of index information,the original reliability allocation of state varia bles are calculated and updated by adopting the fuzzy evaluation method.And then the modified evidence sources and combination rules are utilized to evaluate the bushing condition level.Finally,the results of case study show that this method is accurate and effective.