Degree of polymerization mapping Raman feature extraction of oil-paper insulation aging based on quadratic mutual information.

To assess the aging of oil-paper insulation, an accelerated aging experiment is executed. Raman spectroscopy, a nondestructive detection method with access to component identification and fault diagnosis, is used to analyze the aging of oil-paper insulation. Raman feature of oil-paper insulation aging with a close relationship with the degree of polymerization is obtained based on the concept of quadratic mutual information. By analyzing the relationship between the extracted feature and the degree of polymerization of samples at different aging degrees, the feasibility of reflecting the aging degree of oil-paper insulation is determined. By load analysis, the chemical correlation between the extracted feature and oil-paper insulation aging is clarified. For eight test samples, the prediction error of degree of polymerization based on Raman features is less than 50. These results show that the features extracted in this paper are helpful to realizing the Raman spectrum diagnosis of oil-paper insulation aging.