STUDY ON THE EFFECT OF THE CURRENT DISTRIBUTION ON STABILITY OF A SUPERCONDUCTING MULTI-STRANDED CABLE.

多股超导电缆的稳定性受到股线间初始电流分布和部分股线失超后的瞬态均流的强烈影响。本文首先研究了多股超导电缆稳定性的研究现状。很明显，导管导体（CICC）电缆每根股线电感的微小偏差可能会导致股线之间电流分布的严重不平衡。然而，目前还没有足够的研究来解释多股电缆的电流分布与其稳定性之间的关系。对双股电缆的电流传输特性和稳定性进行了实验研究。当股线的表面在没有绝缘涂层的情况下自然氧化时，从淬火股线到另一股线的电流传递比股线之间的热传递快。双股缆索的稳定性变得更高 关于我们 由于瞬态热传递到液氦的影响，然后用一个表面无涂层的三重态超导电缆研究了三重态内电流分布对其稳定性的影响。最小猝灭能（MQE）已被测量与不同的初始电流分布在三重态。很明显，可以最大化MQE的初始电流分布随着外部磁场、总传输电流和热输入的持续时间而变化。在不同矩阵结构和不同交叉电阻的紧凑股线电缆的实验中，得到了电缆内部均流特性之间同样复杂的关系。低交叉电阻电缆的最小失超能量并不总是大于高交叉电阻电缆的最小失超能量。上述实验结果表明，超导电缆的稳定性不仅与电流分布特性有关，还与单股稳定裕度、股间传热特性和冷却条件等参数有关。根据超导线圈的真实的使用条件来设计超导电缆是十分必要的。少

The stability of a multi-stranded superconducting cable is strongly influenced by the initial current distribution among strands and the transient current sharing after a quench of a part of stands. At first, we researched the previous studies about the stability of a multi-stranded superconducting cable. It became clear that the small deviation of the inductance of each strands for a cable in conduit conductors (CICC) may cause the large unbalance of the current distribution among strands. However, there are not enough studies which can explain the relation between the current distribution of a multi-stranded cable and its stability. We studied experimentally the characteristics of the current transfer and stability of a two-strands cable. The current transfer from the quench strand to the other strand is faster than the heat transfer between strands, when the surfaces of strands are naturally oxidized without an insulation coating. The stability of a two-strands cable becomes higher … More than that of a monolith cable because of the effect of the transient heat transfer to a liquid helium. Then a triplet superconducting cable without any coating on its surface has been used to study the influences of the current distribution within the triplet on its stability. The Minimum Quench Energies (MQE) have been measured with different initial current distributions within the triplet. It became clear that the initial current distribution, which can maximize the MQE,changes with the external magnetic fields, the total transport current and the time duration of heat inputs. The same complicated relations between the current sharing properties within the cables were obtained in the experiments of the compacted strand cable with different matrix structures and different crossover resistance. The minimum quench energies of the cable with low crossover resistance were not always larger than those of the cale with high crossover resistance. Above experimental results showed that the stability of the superconducting cable is affected with not only the current distribution properties but also other parameters such as the stability margin of a single strand, the heat transfer properties between strands and the cooling conditions. It is necessary to design the superconducing cable according to the condition of the real use of the superconducting coils. Less