管内电缆导体绞缆序列比对耦合损耗作用的优化计算

Optimization Calculation Concerning Effect of Cabling Sequence Ratio on Coupling Loss for Cable-in-conduit Conductors

建造中的国际热核试验堆以及国内准备建设的聚变工程实验堆上的管内电缆导体(cable-in-conduit conductor,CICC),将运行在快速励磁的大电流复杂磁场中,这使得中心螺线管线圈(central solenoid,CS)上的CICC导体会受到约12 T磁场的冲击。因此,现有的CICC已采用铌三锡(Nb3Sn)导体,Nb3Sn导体应变敏感性不仅导致电缆临界性能的退化,而且导体中各级绞缆扭距序列对耦合损耗影响很大。为此,对目前ITER项目建议的CS磁体上多种导体的绞缆结构,开展了不同扭距序列对耦合损耗作用的探索。研究分析显示:扭距长度不是决定多级绞缆CICC导体耦合损耗数量大小的唯一因素;当导体中各级绞缆的扭距序列比接近1时,耦合损耗会极大减小。测试数据与数值模拟结果对比分析表明:通过合理选择扭距序列比可以优化计算CICC导体的耦合损耗。

The International Thermal-nuclear Experimental Reactor （ITER） built by seven partners and the China fusion engineering testing reactor to be built in the future, will run in the complex magnetic field excited by large currents quickly, which makes the cable-in-conduit conductor （CICC） of the central solenoid （CS） magnet suffer the impact of the magnetic field about 12 T. The Nb3Sn conductor has been used. The strain sensitivity of Nb3Sn-based conductor leads to the degradation of critical performance. Moreover, the cabling sequence ratio of all stages in cable has an important influence on the coupling loss of conductors. Therefore, for the various cabling structures of conductors on CS magnet proposed for ITER, the exploration of the effect with the different cabling sequence ratio on coupling losses is carried out. The analysis shows that the twist pitch is not the only factor to decide the magnitude of coupling losses in multistage CICC. When the cabling sequence ratio of the conductor is close to 1, the coupling loss of CICC will decrease. The contrastive analysis of test data and numerical simulation show that the coupling loss calculation of CICC can be optimized through the proper selection of twist pitch.