Temperature state of electrical insulation of a superconducting DC cable

•A mathematical model governing the temperature distribution in the electrical insulation layer is constructed.•A quantitative assay is carried out for the electrical insulation layer of a superconducting cable.•The results make it possible to evaluate the applicability of specific electrical insulating materials. The purpose of the study was to build a nonlinear mathematical model governing the steady-state one-dimensional temperature distribution in the electrical insulation layer made in the form of a long hollow circular cylinder whose surfaces are given a constant electric field potential difference. By means of this model, integral ratios, which connecting the parameters of the temperature state of this layer, the heat transfer conditions on its surfaces and the temperature-dependent heat conduction coefficient and the electrical resistivity of the electrical insulating material with a given electrical potential difference, were built. A quantitative assay of the integral ratios is carried out with regard to the electrical insulation layer of a superconducting cable cooled by liquid nitrogen.