Effect of different temperature gradient distributions on the variation of dielectric spectrum in superconducting cables

China's energy resources are mainly distributed in the west and north, while electricity demand is concentrated in the centre and east. This distribution leads to the need for cross-regional, long-distance and large-scale energy transmission. The western region is rich in hydropower, thermal power, wind and solar energy resources, as well as oil and natural gas resources, which has led to the implementation of large-scale energy transmission projects, such as the ‘West-to-East Electricity Transmission’ and the ‘West-to-East Gas Transmission’. High-temperature superconducting power transmission technology uses high-temperature superconducting materials to replace traditional copper and aluminium wires for power transmission. Since the thermal conductivity of different insulating materials varies with the length of the superconducting cable system, a temperature gradient distribution occurs during pre-cooling and warm-up. Therefore, this paper focuses on the relationship between the temperature gradient distribution and the variation of the dielectric spectrum of each layer of PPLP materials.