An HTS CORC Conductor with a Stainless Steel Sheath: Numerical Simulation and Electromagnetic Properties

The rapid pace of urbanization has significantly elevated short-circuit currents in the grid, often surpassing the interrupting capacity of circuit breakers. This has turned limiting fault currents into a significant technical and economic challenge for the power grid. The superconducting fault current limiter (SFCL) offers distinct advantages, including a rapid current limiting response, self-triggering capabilities, minimal losses, and fast recovery. However, current SFCLs used in power grids face challenges related to the substantial use of superconducting materials, which usually exceeds cost constraints in medium and low voltage lines. The high temperature superconducting (HTS) Conductor on Round Core (CORC) cable offers superior mechanical properties and exceptional current carrying capacity. Therefore, the SFCL that utilizes the CORC conductor for current limiting boasts higher current capacity and lower production costs, enhancing both reliability and cost-effectiveness. To ensure the safety and efficiency of the CORC conductor, critical factors such as the critical current and alternating current (AC) loss must be considered when HTS CORC conductors are applied on alternating currents. This paper presents a numerical analysis of the electromagnetic field within an HTS CORC conductor that comprises six superconducting tapes with reversal winding and a stainless steel sheath. The analysis is based on the T-A formulation and finite element method (FEM). The findings indicate the critical current of this CORC conductor is 1070 A. Furthermore, the study reveals the impact of applied current and self-field on AC loss variations and branch shunting between the superconductor layer and stainless steel sheath: when the applied current exceeds 3000A, the current of the sheath layer will exceed that of the HTS layers, achieving the effect of shunt protection. This study paves the way to investigate the feasibility of CORC conductor working for an SFCL.