Cryogenic components for a superconducting DC-rail.

The power distribution at high current industrial applications like e. g. aluminum smelters, chlorine electrolysis or graphitization plants are mainly realized in the form of large cross section DC-rails made of copper or aluminum ― they handle up to some hundred kA. Superconductors offer the advantage of a higher current density compared to conventional conduction. Reductions in resistive losses, installation area and prize are the benefits of that technology. Concept, design and experimental results of the main components of a cryogenic cooling system for a superconducting DC-rail are discussed in this paper. A high power cryocooler based on the pulse tube principle with 400 W cooling capacity at a temperature of 65 K is described as well as a double acting cryogenic liquid piston pump. This pump delivers a subcooled liquid nitrogen mass flow of up to 0.5 kg×s−1 against a pressure drop of 2 bar and is fully submerged into the cryogenic liquid inside its reservoir.