Hyperspectral-Based Corona Aging Evaluation for Composite Insulators

Composite insulators have been widely used in transmission lines due to good water repellency and hydrophobic migration. Corona discharges aggravate the aging of composite insulators. To this end, a method was proposed to evaluate the corona aging of composite insulators based on hyperspectral technology. Firstly, the new composite insulating silicone rubber sheet was subjected to corona aging, the Fourier infrared spectrum of the samples was analyzed, by which the samples were classified into six categories. Then, the reflection intensity at different bands on the surface of the silicone rubber sheet was obtained by using a hyperspectral imaging camera. Further, the characteristics of the original spectra lines was extracted by the principal component analysis (PCA). Finally, the support vector machines-insulator corona aging evaluation (SVM-CAE) model was established, and 60 sets of data were examined. The effects of different kernel functions on the accuracy of model evaluation were compared. The results of hyperspectral detection and evaluation show that, as the aging time increases, the high spectrum of samples under different aging times has obvious difference. With the increase of aging time, the spectral curves of silicone rubber insulation show a decreasing trend in 600 nm−900 nm bands. After the feature extraction by PCA algorithm, the model classification accuracy with polynomial kernel function was 93.333%.