Research on the Influences of Temperature on Frequency Domain Dielectric Spectroscopy of the ERIP Bushing Capacitor Core

Epoxy resin impregnated paper (ERIP) bushing capacitor core is one of the main insulation part of the capacitance graded bushing. The insulating property of the ERIP bushing capacitor core is influenced by the temperature in the actual operation environmental. In order to explore the influence of temperature on frequency dielectric response of the ERIP bushing capacitor core, the frequency domain dielectric spectroscopy (FDS) is utilized for ERIP bushing capacitor core at different temperature, then a double relaxation Debye model is proposed in the paper. Firstly, the temperature experiment of ERIP bushing capacitor core is carried out, and the FDS test is performed on the bushing core at 20°C, 40°C, 60°C, 80°C and 100°C, respectively. Secondly, the FDS spectrum of the dielectric loss factor (tanδ) and the real and imaginary parts of the complex capacitance are plotted at different temperature. Finally, the influences of temperature on FDS test of ERIP bushing capacitor core are analyzed based on a double relaxation Debye model. The test results and analysis indicated that the entire spectrum of tanδ, the imaginary part of the complex capacitance are shown to shift toward the positive vertical direction and move to the high frequency. A good fitness result is obtained by the double relaxation Debye model, and the degree of fit on the data exceeds 90%. The high-frequency dielectric constant, interfacial polarization loss and dipole polarization loss can be made up for the real part of the complex capacitance. These conclusions can provide a mathematical model for the ERIP bushing capacitor core, which will be supportive for ageing state of bushing core insulation.