模糊综合评价和改进证据理论相融合的变压器状态评价方法研究

Research on state evaluation method of transformer based on fusion of fuzzy comprehensive evaluation and improved D-S evidence theory

针对电力变压器状态评价中各评价指标存在的复杂性和不确定性,借鉴变压器状态评价的多年工作经验,模拟专家诊断思维过程,提出了模糊综合评价和改进D-S证据理论相融合的变压器状态评价方法,通过改进D-S证据理论融合多源信息,不仅解决了高冲突证据融合时产生相悖结论的问题,同时提高了状态评价结果的准确性,模糊综合评价则改善了评价指标界限过于硬化的问题,并结合专家经验采用层次分析法确定模糊综合评价模型的权重集.实例结果表明,该状态评价方法的结果与变压器实际运行状态一致,不仅能定量地从各层次和总体角度反映变压器的健康状况,同时为设备性能的进一步改进提供了一定的科学依据.

In order to avoid the complexity and uncertainty of variables in the state evaluation process of transformers,this paper proposes a state evaluation method of transformer,which is established through the work experience of transformer and expert diagnostic thinking process.The fusion of fuzzy comprehensive evaluation and improved D-S evidence theory is employed to build the evaluation model of the method,of which the analytic hierarchy process is obtained to determine the weight set.With the improved D-S evidence theory,the uncertainty of evidence information is reduced;and the effect of conflict evidences on results is weakened.The fuzzy comprehensive evaluation is suitable for comprehensive evaluation of the project that large number of indicators are difficult to quantify.The proposed method has been applied successfully.The results indicate that the evaluation method can reflect the current state of a transformer quantitatively.Meanwhile,the method can provide the grid manager with theoretical guide in seeking further optimization maintenance strategy and improving further performance of a transformer.