Liquid Nitrogen Cooled Superconducting Power Cable with No Solid Insulation

Abstract

In an attempt to eliminate solid insulation challenges in cryogenic superconducting power cables, a new design concept for liquid cryogen cooled superconducting power cable was investigated. The design is based on superconducting gas insulated line (S-GIL). The design used liquid cryogen as the sole insulation medium. The suitability of the design for medium voltage power cables is discussed and the benefits of eliminating a solid insulation were identified. Experiments on 1-m long model cables with insulator tubes as spacers showed that the design is suitable for cables at 50 kV or higher. The actual limits could not be identified because of the experimental limitations originated from limited standoff distances in the measurement setup used. On a fundamental level, the investigations presented in the study showed a direct correlation between the intrinsic dielectric strength of the cryogen used and the maximum tolerated voltage for a given diameter of the cable system. The results show the promise for liquid nitrogen (LN2) and liquid hydrogen (LH2) cooled cables for various medium voltage applications, including electric aviation and electric ships.

Superconducting liquid cryogen insulated power cables for medium voltage applications

“…For DC HTS cables, with lengths less than 100m, the heat loads typically come from the terminations and heat leak from the cryostat. For the terminations, the heat loads are typically 100 -300 W and the heat load along the HTS cable due to cryogenic leaks is approximately 1 W/m [15], [16].…”

Numerical Studies on Two-Phase Flow of Liquid Nitrogen to Cool HTS Power Cables

“…The power transmission capacity may be affected as the critical current reduces due to the rise in temperature of the cable core [3]. This temperature rise results in two-phase of cryogen which enhances probability of voltage breakdown due to the presence of bubbles [4] [5] resulting in the occurrence of faults. In addition, this also affects the thermo-hydraulic characteristics of Figure 1.…”