Numerical Simulation on Magnetic Field Generated by Screening Current in 10-T-Class REBCO Coil

Ueda, Hiroshi; Imaichi, Yohei; Wang, Tao; Ishiyama, Atsushi; Noguchi, So; Iwai, Sadanori; Miyazaki, Hiroshi; Tosaka, Taizo; Nomura, Shunji; Kurusu, Tsutomu; Urayama, Shin‐ichi; Fukuyama, Hidenao

doi:10.1109/tasc.2016.2535965

Cited by 55 publications

(22 citation statements)

References 12 publications

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“…The Hastelloy substrate is not considered in the circuit analysis since it has a large value of resistance. The equivalent resistance of superconducting layer is calculated according to the n-value model, and the critical current density is obtained from an approximate equation derived from the experimental data [8]. Since there is no insulation between turns, the contact resistance has to be considered in the radial direction.…”

Section: Simulation Methodsmentioning

confidence: 99%

Electromagnetic and thermal simulation of stacked NI REBCO pancake coils after normal-state transition

Miyao

Igarashi

Noguchi

2019

JAE

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This paper presents the current and thermal phenomena of multi-stacked No-Insulation (NI) REBa2Cu3O7-x (REBCO, RE = Rare Earth) pancake coils during a local normal-state transition. An NI winding technique is expected to enhance the thermal stability of REBCO pancake coils, and it was verified in numerical simulations on a single pancake coil. However, a multi-stack of pancake coils are used to generate a high magnetic field in practical applications. When a normalstate transition occurs in one of multi-stacked pancake coils, it may deteriorate the stability of the other pancake coils. Therefore, we have developed a numerical simulation code to clarify the current and thermal behaviors of multi-stacked NI REBCO pancake coils using a partial element equivalent circuit model and a thermal finite element method.

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Section: Simulation Methodsmentioning

confidence: 99%

Electromagnetic and thermal simulation of stacked NI REBCO pancake coils after normal-state transition

Miyao

Igarashi

Noguchi

2019

JAE

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“…The circuit element of each winding turn is composed of the REBCO layer resistance , the copper matrix resistance , and the inductance [13]. Here, to consider the magnetic field and temperature dependencies of REBCO critical current characteristics, a power index E-J characteristic model given in [14] is used as a critical current model of REBCO layer resistance. The resistances of the conductive epoxy resin and the contact between REBCO coil and conductive epoxy resin are represented as and , respectively.…”

Section: Simulation Modelmentioning

confidence: 99%

Sudden Discharging and Overcurrent Simulations of REBCO Coils Coated With Conductive Epoxy Resin

Mato

Noguchi

2021

IEEE Trans. Appl. Supercond.

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In 2011, a no-insulation (NI) winding technique was first proposed. Rare-Earth Barium Copper Oxide (REBCO) pancake coils using the NI winding technique are promising to generate an ultrahigh magnetic field, because the NI winding technique drastically enhances the thermal stability. When a local hot spot appears on a turn of the NI REBCO pancake coil, the enforced current can bypass into the adjacent turns to suppress the Joule heat generation. Recently, different types of REBCO coils to enhance the thermal stability by escaping the current flow from a local hot spot have been researched and developed. A few years ago, a REBCO single pancake coil whose upper surface was coated with conductive epoxy resin was proposed as one kind of NI winding techniques. The high thermal stability of conductive-epoxy-resin-coated (CERC) REBCO single pancake coil was demonstrated through an overcurrent test. However, the current behavior in the coil is still unclear. Therefore, we have newly developed an equivalent circuit model for CERC REBCO pancake coils. The sudden discharging and overcurrent tests were simulated for CERC REBCO pancake coils, and the resistance parameters were varied to investigate the coil stability.  Index Terms-Conductive-epoxy-resin-coated REBCO coil, magnet stability, no-insulation winding technique, quench protection.

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“…Modelling of magnetization currents in REBCO coils is a problem that has been widely studied in superconducting applications, especially for computation of AC losses [19][20][21][22][23] as they have a significant impact on the quality of the magnetic field or the refrigeration requirements for instance. However, we propose here to investigate these transient behaviours for protection purposes.…”

Section: Introductionmentioning

confidence: 99%

Calculation of the local current density in high-temperature superconducting insulated rare earth–barium–copper oxide coils using a volume integral formulation and its contribution to coil protection

Rozier

Badel

Ramdane

et al. 2019

Supercond. Sci. Technol.

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High-temperature superconducting materials have remarkable current-carrying capabilities, even when operated under high magnetic fields. Since long rare earth-barium-copper oxide (REBCO)-coated conductors are now available (thanks to improvements in the fabrication process) this material has become an attractive option for high field magnet applications. However, such extreme operating conditions require an efficient quench protection system to prevent the coil from developing damaging hot spots, which greatly depends on the winding used. We focus here on the protection of insulated HTS coils against thermal runaways that can locally destroy the magnet. We developed a transient two-dimensional (2D) axisymmetric model using a volume integral formulation based on generalization of the partial element equivalent circuit method to compute the local current density distribution inside REBCO-insulated coils and account for local performance variations. Indeed, the most interesting property of integral methods is the requirement that only active regions are meshed, which leads to a significant reduction in the size of the problem. The formulation is introduced for general 3D cases and its adaptation to 2D axisymmetric problems is detailed. The formulation has been validated thanks to a bulk magnetization benchmark, the results of which (obtained with the finite element method) were compared with our integral formulation solution. The model has also been compared with experimental data obtained on a double pancake coil. The objective is to study the effects of magnetization on the transient voltage due to dynamic current distribution when ramping up the magnet so as to be able to determine some key parameters associated with coil protection. Such an approach is developed on a small-scale test case and the transient behaviours observed are discussed.

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Numerical Simulation on Magnetic Field Generated by Screening Current in 10-T-Class REBCO Coil

Cited by 55 publications

References 12 publications

Electromagnetic and thermal simulation of stacked NI REBCO pancake coils after normal-state transition

Electromagnetic and thermal simulation of stacked NI REBCO pancake coils after normal-state transition

Sudden Discharging and Overcurrent Simulations of REBCO Coils Coated With Conductive Epoxy Resin

Calculation of the local current density in high-temperature superconducting insulated rare earth–barium–copper oxide coils using a volume integral formulation and its contribution to coil protection

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