Preliminary Design of a Superconducting LVDC Power Cable for Tokamak Application

Abstract

Tokamak device requires a very high current power supply from the local power distribution sources to the targeted magnets such as toroidal field (TF) coils and poloidal field (PF) coils. This paper presents a preliminary design of a 30-m/1-kV/10-kA low voltage direct current (LVDC) superconducting cable for the potential in Tokamak applications. The outer diameter of the DC cable is 122.41 mm, and the pressure drop of liquid nitrogen (LN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) in the inner and outer channels is about 6.59 kPa. The flow velocity of inner and outer LN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> channels are 0.5 m/s and 0.25 m/s, respectively. The temperature rise of the entire cable was designed to be less than 5 K, which enhances the electricity supply safety and reliability. These preliminary design lays some technical bases for achieving high current and low loss power transmission. The designing results show that the LVDC superconducting cable has significant potentials for Tokamak applications compared with conventional copper cables.