A Method for Evaluating the Aging State of Oil-Paper Insulation Using Frequency Domain Spectroscopy

Power transformer is one of the most important equipment in power system, which is of great significance to supply the electricity continuously. In order to evaluate the aging state of oil-paper insulation in transformer effectively, the dielectric characteristics of oil-paper insulation under different aging degrees were studied by frequency domain spectroscopy (FDS), and the relationship between characteristic parameters and aging time was established based on Havriliak-Negami (H-N) model. Finally, the field transformer was tested by this method. The results show that with the increase of aging degree, the FDS curves do not change obviously in high and low frequency band, but increase significantly in medium frequency band, and the curves present “jujube core” shape; The characteristic parameters extracted according to the H-N model have a good corresponding relationship with the aging degree; The feasibility of this method was verified by the application of field transformer.