Design of Cryogenic Systems for 154 kV HTS Power Cable

Cryogenic cooling is necessary for HTS power cables to perform their intended function. In the cooling process, sub-cooled liquid nitrogen is circulated by a pump to absorb and dissipate the heat generated in the cable and introduced from outside. To ensure successful cooling, the hydraulic characteristics of the cooling passages of the HTS cable as well as the thermal load have to be understood. The thermal load of the cable determines the capacity of the cooling system, and the pressure drop in the cooling passage is an important design parameter that determines the length and diameter of the cable and the capacity of the circulation pump. In this study, a cryogenic cooling system equipped with two cooling passages was designed. In the system, sub-cooled liquid nitrogen flows through the core (former) and the circumferential side of the cable in the same direction to cool the cable, and then returns to the cryogenic cooling system through the return line. In this study, the thermal load of the cable system was analysed to determine the type and capacity of the cryogenic cooler, and the pressure drop in the cooling passage was analysed to determine the pressure of the liquid nitrogen and the size and shape of the cooling passages of the cable.