Massive Mitigation of Transport AC Losses in Superconducting Hybrid CORC-TSTC Cables

TL;DR

This study demonstrates that independent current feeding in hybrid CORC-TSTC superconducting cables significantly reduces transport AC losses by up to 90%, enhancing power transmission efficiency.

Contribution

It reveals the critical impact of current injection strategy on electrodynamics and loss reduction in hybrid superconducting cables, proposing electrical decoupling as an effective solution.

Findings

Independent feeding suppresses inter-conductor current exchange.

Non-insulated feeding causes strong current redistribution and waveform distortion.

AC losses are reduced by up to 90% with independent current feeding.

Abstract

High-current superconducting cables are emerging as key enablers for next-generation power transmission systems; however, their deployment is often limited by transport AC losses. Hybrid superconducting cables combining Conductor-on-Round-Core (CORC) and Twisted Stacked-Tape Conductor (TSTC) architectures have recently been proposed as a promising route toward cables with high current capacity and compact form factors. However, their electrodynamic response under transport current operation remains poorly understood, particularly regarding how current injection conditions govern internal current redistribution. Here, we employ a fully-3D electromagnetic model, previously validated against magnetisation experiments in equivalent cables, to investigate the influence of current injection strategy on the electrodynamics of hybrid CORC-TSTC cables under self-field conditions. By comparing configurations in which the total current is either injected through a common connection between the CORC and TSTC conductors (non-insulated feeding) or supplied independently to each conductor (insulated feeding), we show that electrical coupling in non-insulated designs leads to strong current redistribution, pronounced waveform distortion and elevated AC losses once the CORC layers approach magnetic saturation. In contrast, independent current feeding suppresses inter-conductor current exchange, stabilises the current waveforms, and exhibits an outstanding reduction in transport AC losses of up to 90% at practical operating currents, compared with conventional feeding schemes. These findings reveal the central role of the current injection strategy in governing the internal electrodynamics and energy dissipation of hybrid superconducting cables, and identify the electrical decoupling of the constituent conductors at the feeding point as a simple and scalable route toward ultra-efficient power cables.