Superconducting DC energy pipeline incorporates HTS DC cables and the LNG pipeline, and the overall efficiency is improved compared to the conventional HTS DC cables. In the energy pipeline, LNG is cooled down to 90 K at which Bi2223 tapes can still conduct moderate currents although the critical current density J_c at 90 K drops to about half of that at 77 K. According to the power law, three-dimensional models are constructed to investigate and contrast the current distributions and degradations on helical Bi2223 tapes of the bipolar double-core DC cables under different voltage levels. It is found that the current distributions on Bi2223 tapes tend to the sides which are closer to the cable of opposite polarity. Both the perpendicular and parallel magnetic fields on the surfaces of helical tapes are compared in ±100 kV and ±10 kV cables. The average degradations of critical current density of the cable influenced by the magnetic fields are estimated and the results indicate that the degradations of critical current density are similar with different insulation distance between poles.

中文翻译：

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超导双极直流输电管道Bi2223带内电流分布分析


超导直流能源管道将高温超导直流电缆和液化天然气管道结合在一起，与传统高温超导直流电缆相比，整体效率得到了提高。在能源管道中，LNG被冷却到90 K，此时Bi2223带仍然可以传导中等电流，尽管90 K时的临界电流密度Jc下降到77 K时的一半左右。根据幂律，三维模型构建了双极双芯直流电缆螺旋 Bi2223 胶带在不同电压水平下的电流分布和衰减研究并对比。发现Bi2223胶带上的电流分布倾向于靠近相反极性电缆的一侧。比较了 ±100 kV 和 ±10 kV 电缆中螺旋带表面的垂直和平行磁场。估算了磁场影响下电缆临界电流密度的平均衰减量，结果表明，不同极间绝缘距离下，临界电流密度的衰减量相似。