Abstract：Superconducting DC energy pipelines combine high temperature superconducting (HTS) DC transmission lines with long-distance liquefied natural gas (LNG) transmission lines where the flowing LNG acts as the refrigerant for the superconducting cable in the pipeline.This greatly increases the overall system energy transmission density and efficiency.The conductors then need to be carefully designed to ensure the safety and reliability of the high-capacity superconducting transmission system for the special operating conditions of superconducting DC energy pipelines.This study analyzed the critical current density degradations of the high temperature superconducting tapes influenced by the magnetic fields at the pipeline operating temperature and the effects of the copper former during short-circuit faults in the superconducting cable.The analysis was then used to optimize the conductor design of a ±10 kV/1 kA bipolar coaxial superconducting DC energy pipeline.The results indicate that at least 12 HTS tapes are required for a single pole and the minimum cross-sectional area of the copper former is 1.48×10-4 m2.The thermal stability of the superconducting DC energy pipeline during a short-circuit fault was then verified by finite element simulations.The conductor design method presented in this paper is also applicable to the design of superconducting DC energy pipelines with various voltage and current levels and pipeline structures.
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