Advantages of water-cooled Peltier current leads for HTS devices

Efficiency of high-temperature superconducting (HTS) devices can be increased by reducing the heat leak into the cold zone through current leads. There are many models of cryogenic current leads; however, the Wiedemann-Franz law severely restricts the possibility of their optimization. According to our experience, the qualitative improvement of the characteristics of the current lead can be achieved using Peltier element as a heat pump, which prevents the penetration of heat inside the HTS device. Test samples of Peltier current leads (PCLs) were mounted on the experimental HTS DC power transmission lines constructed in Japan. Currently we are studying the possibility of increasing the PCL efficiency using water-cooling of the hot side of the current lead.