Frequency Domain Dielectric Response of Oil-Paper Capacitor Bushing Under Uneven Thermal Aging

The main function of oil-paper capacitor bushing is to achieve power transmission, electric insulation, and mechanical support for transformer winding and external wires, so its insulation state is important for equipment safety. Frequency domain spectroscopy (FDS), as a rapid and nondestructive test technique, was widely utilized for evaluating the thermal aging degree of bushing insulating paper. However, there is still a lack of studies about the uneven thermal aging status of bushings, and the FDS characteristics of bushing under uneven thermal aging are not clear yet. Therefore, this research explores the FDS characteristics of bushings with uneven thermal aging status. The outcomes show that for unevenly aged bushings, as the average polymerization degree decreases, the real and imaginary components of the FDS data change significantly and regularly, Besides, the location change of the insulation's weakest area has no significant impact on the FDS data.