High-Field Frequency Domain Dielectric Properties Analysis of Extra-High-Voltage XLPE Submarine Cable Based on Extended Debye Model

This paper is devoted to the use of circuit modelling to analyze the evolution mechanism of dielectric properties of 500 kV Extra-High-Voltage (EHV) submarine cables at different high field strengths, and to promote the application of high-field broadband dielectric spectroscopy in the condition inspection of power equipment. Taking new and aging submarine cables as analysis cases, based on extended Debye model and GA-LMA fusion algorithm, the test results of frequency domain dielectric response (HV-FDS) of high-voltage submarine cables at different test voltages are compared with the calculated results of Debye model parameters. Meanwhile, by identifying the circuit model parameters, the correlation relationship between the characteristic parameters geometric capacitance C 0 and insulation resistance R 0 and the measured voltage is constructed. The results show that the measured results of HV-FDS for new and aged submarine cables are roughly similar to the results calculated by the extended Debye parameter model reconstruction, and the goodness-of-fit values are both greater than 0.9. With the increase of the test voltage, the geometric capacitance C 0 of the new and aged submarine cables does not change significantly, but the insulation resistance R 0 gradually decreases as a function of the measured voltage. The results of this paper provide theoretical support for the application of high-field broadband dielectric spectroscopy in the condition detection and reliability assessment of Extra-High-Voltage submarine cables.