基于灰色关联分析和聚类云模型的变压器油纸绝缘状态评估

Evaluation of transformer oil-paper insulation status based on grey relational analysis and a cluster cloud model

电力变压器复合油纸绝缘状态的准确诊断对电力系统安全稳定运行以及设备自身运维具有重要指导意义。针对油纸绝缘介电响应少数特征量评估和未考虑系统随机性导致评估不准确的问题,提出基于灰色关联分析(grey relational analysis,GRA)与聚类云模型的评估方法。首先,基于回复电压法和扩展德拜模型提取5个相关特征量,建立油纸绝缘状态评估体系。然后,针对多特征量在反映绝缘状态的敏感性差异,采用组合赋权法综合GRA和改进层次分析法,避免了数据信息丢失,使权重分配更加合理。最后,利用云模型雾化特性反映数据随机性,全面考虑评估指标等级分类边界的随机性和模糊性后构建了聚类云模型隶属度选择器。通过多台不同糠醛含量变压器实测数据进行验证表明,该评估方法不仅能够准确反映变压器实际绝缘状态,而且能体现其劣化趋势,为检修策略的制定提供参考依据。

Accurate diagnosis of the composite oil-paper insulation state of power transformers is of great guiding significance for the safe and stable operation of power systems and the operation and maintenance of equipment itself.In this paper,an evaluation method based on grey relational analysis(GRA)and a clustering cloud model is proposed to solve the problem of inaccurate evaluation caused by few characteristic quantities of the dielectric response of oil-paper insulation and failure to consider the randomness of the system.First,based on the recovery voltage method and the extended Debye model,five relevant features are extracted to establish the oil-paper insulation state evaluation system.Second,in view of the sensitivity differences of multiple feature quantities in the reactive insulation state,a combination weighting method combining GRA and an improved analytic hierarchy process is used to avoid data information loss and make the weight allocation more reasonable.Finally,it uses the atomization characteristics of the cloud model to reflect the randomness of the data,and comprehensively considers the randomness and fuzziness of the classification boundary of the evaluation index grade.After that a clustering cloud model membership selector is constructed.The validation of measured data from multiple transformers with different furfural content shows that the evaluation method can not only accurately reflect the actual insulation status of the transformer,but also reflect its deterioration trend,providing a reference basis for the formulation of maintenance strategies.