Terahertz-based Method for Detecting the Degree of Aging of Insulating Oils

In order to solve the shortcomings of the traditional detection methods of insulating oil aging degree, such as lossy testing and cumbersome detection steps, this paper realizes the non-destructive and rapid detection of the aging degree of insulating oil by using terahertz technology. Firstly, different temperature gradient aging degree insulating oil samples were prepared in the laboratory, the spectral medium loss and terahertz time spectrum were tested, the terahertz characteristic parameter absorption spectrum integral value $S_{\alpha}$ was analyzed and extracted, the $120^{\circ} \mathrm{C}$ sample was used to establish a linear model of $S_{\alpha}$ and the aging degree, and the $130^{\circ} \mathrm{C}$ sample was used to verify the validity of the model, and the results showed that the fit of the model was better than the traditional method of testing. The results show that the goodness of fit of the model is more than 0.97, and it is able to evaluate the aging degree of insulating oil effectively and quickly without any loss, and it can be used to invert the aging degree of insulating oil according to the terahertz test results.