Influence of properties of double-insulated materials on the maximum permissible current of a cable product

Abstract

A thermodynamic model of the operation of a loaded double-insulated cable product has been developed. The obtained mathematical relation makes it possible to determine the maximum permissible current of a single-core double-insulated cable product depending on the materials and dimensions of the insulation layers and the conditions of installation. The dependence of the maximum permissible current for a hypothetical cable product with a copper core and double insulation on the ratio of the radii of the insulation layers when laid in air is constructed for cases where the first insulation layer is a material with a higher thermal conductivity coefficient, the second layer – with a lower one, and vice versa. In the first case, with an increase in the ratio of the radii of the insulation layers, the maximum permissible current decreases, and in the second case, the dual current increases by almost 15 %. The dependence of the maximum permissible current of a real H07V-K cable of typical dimensions on the ambient air temperature, which is real for the territory of Ukraine, is calculated. Recommendations on the practical application of the H07V-K cable for connecting mobile power sources in war conditions are given.