Abstract: A superconducting cable system in which at least one superconducting electrical cable is arranged in a cryostat which consists of two metallic tubes, which are arranged concentrically and at a distance from one another. Vacuum insulation is fitted in the circumferential gap formed by the distance between the tubes, which vacuum insulation consists of spaces composed of a material having low thermal conductivity and plastic films coated with a metal and having high reflectivity. The gap is evacuated. In addition, thermally insulating material (9) is arranged in the gap, and its thermally insulating characteristics are independent of the vacuum which is produced between the two tubes (5, 6).