Heat loss analysis of a 10 kA warm dielectric HTS DC cable

• A 10 kA HTS power cable has been demonstrated, both the cable and its supporting system are introduced.
• The structure and its heat losses of the 10 kA HTS cable system are discussed in detail.
• A dual vacuum layer insertion technology is developed to connect the cryogenic envelope segment of the cable.
• The termination and cryogenic envelope are the main heat loss sources of the cable.
• The actual power consumption for the 1698 W of the HTS cable is 39 kW, 48% of that consumed by the aluminum bus.

A 10 kA/360 m warm-dielectric high-temperature superconducting direct current (DC) power cable system (10 kA cable), supported jointly the Chinese government and industrial enterprise, was developed and has been operating as a branch circuit to transmit power for a 320 kA aluminum electrolyzing production line for more than 10 months at an industrial plant in central China. Both the 10 kA cable and its supporting system of the cable system are introduced. The cryogenic system for the 10 kA cable adopts closed loop and the sub-cooled liquid nitrogen is forced to flow inside by a pump. The design of corrugated cryogenic envelope pipe is modularized and every independent module has two standardized joints, which makes it easy to integrate with the other pipes and the terminations. The heat loss sources and the structure including both the termination and the cryogenic envelope pipe of the 10 kA cable are discussed. The total heat loss of the 10 kA cable excluding the loss of cryogenic pipe for liquid nitrogen backward flowing is designed to be less than 1698 W at 10 kA, and the heat loss was compared and discussed with that of the aluminum bar. The field test and commissioning of the cable show that the 10 kA cable performs steadily and its heat loss is less than the expected value.