Fault Current Analysis in a Tri-Axial HTS Cable
Fault Current Analysis in a Tri-Axial HTS Cable
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DOI：
10.1109/tasc.2010.2042941
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发表时间：
2010-03
影响因子：
1.8
通讯作者：
N. Hu;M. Toda;A. N. Ozcivan;T. Yagai;M. Tsuda;T. Hamajima
中科院分区：
文献类型：
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作者：
N. Hu;M. Toda;A. N. Ozcivan;T. Yagai;M. Tsuda;T. Hamajima
三轴电缆因其结构更紧凑、漏磁场小、发热和交流损耗低等优点而得到迅速发展。另一方面，由于同心层半径不同，导致固有的三相电流分布不平衡。在我们之前的研究中，证明了所提出的由两个纵向部分组成的三轴电缆，其绞距可调整，可以传输平衡的三相电流。然而，在电缆安装到实际电网中之前，应确保电缆在稳态运行和故障情况下的热可靠性。在平衡电流分布下稳态三轴电缆的热平衡计算使我们能够估计电缆的热参数，例如入口和出口温度、压降和工作温度。当故障情况下相电流突然变化时，由于故障相和正常相之间的互感，剩余相电流变大。对典型故障的模拟表明，高温超导带上的铜稳定剂用量是为了保证稳定性和安全性。研究发现，2mm厚的铜可使电缆温度保持在110K以下。
Tri-axial cable has been rapidly developed recently because of the advantages such as more compact structure, small leakage field, and low heat and AC losses. One the other hand, it causes an inherent imbalanced three-phase currents distribution due to the different radii of concentric layers. In our previous research, it is demonstrated that a proposed tri-axial cable composed of two longitudinal sections with adjusted twist pitches can transmit balanced three-phase currents. However, before the cable can be installed in a real grid, the heat reliability of the cable in steady-state operation and fault condition should be ensured. The heat balance calculation of the tri-axial cable in steady state under the balanced current distribution allows us to estimate thermal parameters of the cable such as inlet and outlet temperatures, pressure drop and operation temperature. When a phase current suddenly changes under fault conditions, the remaining phase currents become large because of mutual inductances between fault and sound phases. Simulation of the typical fault suggests the copper stabilizer amount on the HTS tape for stability and safety. It is found that copper of 2 mm in thickness keeps the cable temperature under 110 K.