基于小波包能量熵和Fisher判别的油纸绝缘老化拉曼光谱诊断

准确诊断油纸绝缘材料的老化程度是保证油纸绝缘设备安全运行的重要技术手段。拉曼光谱在物质成分分析及状态诊断领域已经普遍应用。结合实验室搭建的油纸绝缘拉曼光谱分析平台,根据绝缘纸的平均聚合度将加速热老化实验获得的油纸样本分为四个老化阶段。通过对不同老化样本拉曼光谱所包含的能量信息分析,运用小波包能量熵提取特征量,结合Fisher判别法构造判别函数,建立基于拉曼光谱老化特征量的油纸绝缘老化诊断模型,并收集现场变压器油样验证诊断模型的泛化能力。结果表明,两个判别函数能区分不同老化阶段的绝缘油样,对于老化样本的判别正确率达到84.2%。拉曼光谱结合小波包能量熵和Fisher判别分析法能够有效地对油纸绝缘老化状态进行诊断。

Raman Spectroscopy Diagnosis of Oil-Paper Insulation Ageing Based on Wavelet Packet Energy Entropy and Fisher Discrimination

Accurate diagnosis of oil-paper insulation material is an essential technology to ensure the safe operation of equipment insulation. Raman spectroscopy has been widely used in material composition analysis and state diagnosis. In this paper, the oil-paper insulation samples obtained from the accelerated thermal ageing experiment were divided into four ageing stages according to the degree of polymerization of the paper, and researched based on the Raman spectroscopy platform. By analyzing the energy information contained in the Raman spectra of different ageing samples, the feature vector was extracted by Wavelet Packet Energy Entropy, and the discriminant function was constructed by Fisher discriminant method. What’s more, the ageing model of oil-paper insulation based on Raman spectroscopy was established, and oil samples of running transformers were collected to verify the generalization ability of diagnostic model. The results show that two discriminant functions can distinguish different ageing stages, and the accuracy rate of ageing samples reaches 84.2%. Raman spectroscopy combined with wavelet packet entropy and Fisher discriminant analysis can effectively diagnose the ageing state of oil-paper insulation.