639 / 2022-03-30 22:49:19

Detection of the Aging State of Insulating Paperboard based on Terahertz Technology

terahertz,oil-paper insulation,aging,Non-Destructive Test

Evaluation of the aging state of oil-paper insulation is an important method to prevent failure of oil-paper insulation. The traditional evaluation method needs to measure the degree of polymerization (DP), which is time-consuming and damages the samples. It is a research hotspot to explore a method for rapid non-destructive testing of the aging state of insulating paper. In this paper, oil-impregnated paperboards with different aging degrees were prepared by accelerated thermal aging. The terahertz time-frequency spectra of different oil-impregnated paperboards were measured by terahertz time-domain spectroscopy, and the spectrum collection range was 0.3~2.0THz. Based on the experimental spectral characteristics, the spectral characteristic peaks were extracted by the Gaussian function, and the relationship between the characteristic peak area and the aging of the oil-impregnated paperboard was studied. It was found that there is a significant semi-logarithmic linear function relationship between the 1THz peak area and DP of oil-impregnated paperboard, and the Pearson correlation coefficient is 0.97.  This relationship can be used to predict the DP of oil-paper insulation. The research results of this paper provide a new idea for the non-destructive evaluation of the aging state of oil-paper insulation using terahertz technology.