Current dependence of heat leak on the terminals in the superconducting DC transmission and distribution system of CASER-2

Abstract

Superconductivity can solve the energy problems in the world as energy saving technologies. In particular, superconducting direct current (DC) transmission and distribution (T&D) systems is promising, as it can be easily extended to large scale energy transmission systems for energy sharing. We are developing criogenic systems for effective cooling of superconducting T&D systems. In the cooling experiments with the 200 m-class superconducting DC T&D system at Chubu University (CASER-2), we have estimated the performance of the system. For example, our superconducting cable is connected to the outside at the terminals using Peltier current leads (PCLs). The PCL is composed of a thermoelectric material and a copper lead. Small thermal conductivity and large thermopower of the thermoelectric modules can effectively insulate the heat leak to the low temperature end. We measured the temperature along the current leads and the heat leak at the terminals. As current leads have an optimal shape factor, the optimum operation current exists. The current dependence of the system performance is discussed.