Conveners
Mon-Af-Po1.20 - Stability of Conductors and Coils I
- Minfeng Xu (GE)
- Etienne Rochepault (Université Paris-Saclay (FR))
Recently, several high temperature superconductor (HTS) companies, such as SuperPower, SuperOx, Shanghai Superconductor Technology (SST), and THEVA, succeeded in improving current-carrying performance of their REBCO products under high magnetic field at low temperature. However, except HTS coils made of SuperPower REBCO tape, there are insufficient reports regarding thermal, electrical and...
As a novel high-temperature superconducting (HTS) conductor structure composed of the stacked 1-mm wide REBCO tapes, Narrow-Staked (NS) wire has been demonstrated to have a significant reduction effect of AC loss and screening current induced field (SCIF) in the insulated HTS coils. Thus, NS wire is a promising HTS conductor design for the practical magnet applications. Meanwhile, due to the...
Abstract:
Comparing with conventional insulated high temperature superconducting (HTS) coil, the no-insulation (NI) one has advantages of high stability, self-protection and fast quench recovery. However, the unstable and non-uniform magnetic field appear in NI coil during exciting owing to too low transverse resistivity among turns. This paper proposed a method for increasing stability and...
When high temperature superconducting (HTS) devices run in the power system, the superconducting tapes may quench due to power system fault. Therefore, quench characteristic is one of the most important characteristics of superconducting tapes. In this paper, in order to obtain the quench characteristics of YBCO coated conductor, we have established an over-current experiment system based on...
NI (no-insulation) winding method have been widely used to develop high field superconducting magnets using REBCO wires due to excellent mechanical and electromagnetic stability. When REBCO magnets are operated in a bath of cryogens such as liquid helium and liquid nitrogen, sufficient cooling is achieved by pool boiling of the cryogen. However, conduction-cooled REBCO magnets must ensure...
We have been studied the no-insulation (NI) technique and co-winding method with various metallic tapes. The improved thermal stability of NI test coils by bypassing the transport current into the transverse direction was experimentally confirmed and reported. However, there are the problems of the transient stability and the reduction of critical current of NI HTS coils due to the thermal and...
The no-insulation coil is expected as a technology that can realize both high current density and high thermal stability which are originally trade-off relationship in REBCO coil application. And this technique has been mainly studied for application to small diameter inner coil of NMR magnet exceeding 30T. In this case, the coil is cooled by 4.2 K liquid helium. On the other hand, we have...
We have tested an intermediate-size HTS stainless steel double pancake coil (132 turns per coil) and discovered dynamic effects during sudden discharge on millisecond scale. Two main approaches have been compared: soft and hard breaks. The soft break is when the power supply is turned off suddenly but the shunt resistors (168 milliohm) is still connected. The hard break uses a high voltage...
