• Proceedings of the KIEE Conference
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• 1986.07a
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• pp.55-59
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• 1986

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.579-580
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• 1987

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.6
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• pp.691-698
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• 2015

Recently, the power industry has a great interest in the superconducting energy storage device as a way to maximize energy efficiency to cope with global warming. A superconducting energy storage device can archive maximization of electric energy use efficiency by storing in the form of a magnetic field energy or a kinetic energy without loss a large amount of electrical energy at the non-peak load and then converting it again into electric energy at the peak load. Therefore, in this study, such as the concept of the superconducting energy storage technologies, the present state of its research and development and its applications are surveyed and analyzed to establish methodology applying the superconducting energy storage technologies to power system.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.86-88
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• 1997

The detection of the normal zones in the coil winding and the initiation of the proper dump sequence have been one of the most important areas in the superconducting magnet technology. In this paper, the process to derive optimal dump sequence has been investigated through quench simulation and analysis of magnetically coupled superconducting magnet system. The magnet terminal voltage and maximum temperature rise in the quench initiated point are calculated with respect to various input variables such as operation current, dump resistance, etc. The experimental system is comprised of sc solenoidal coil, data aquisition device, external circuit breakers and dump resistor. The quench behavior of the magnet(e.g., temperature profile and the voltage signal) was measured. From this results, theoretical predictions were found to coincide with the experimental observations.

• Progress in Superconductivity and Cryogenics
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• v.21 no.3
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• pp.43-46
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• 2019

A rare-earth barium copper oxide (REBCO) superconducting magnet was designed using no-insulation (NI) and multi-width (MW) winding techniques. The proposed magnet is comprised of 58 REBCO-wound single pancake coils with a bore size of 240 mm. When the magnet is operated at 20 K, the center magnetic flux density is designed to reach 3 T with an operational current of 169.55 A, 70 % of its critical current. The critical current was evaluated using experimental data of a short REBCO conductor sample. The designed magnet was then simulated using FEM software with uniform current density model. Magnetic field and mechanical properties of the magnet are evaluated using the simulated data. This magnet was designed as one of the base designs for the project "Tesla-Level Magnets with Large Bore Sizes for Industrial Applications" which was initiated in 2019, and will be wound using REBCO wires with the defect-irrelevant-winding (DIW) technique incorporated to reduce the overall manufacturing cost.

• Progress in Superconductivity and Cryogenics
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• v.11 no.4
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• pp.33-36
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• 2009

An air gap between the pancake windings was provided in this paper to increase the central magnetic field of a high temperature superconducting (HTS) magnet consisting of pancake windings. Unlike the LTS magnet, providing an air gap between the pancake windings increases the central magnetic field of a HTS magnet. Furthermore, the uniformity of the magnetic field near the center of the magnet increased because the pancake windings spread out in wider area. Effects of the air gap on the central magnetic field of an HTS magnet was described in this paper, Calculation of the critical current was carried out by using E-J relation of the HTS wire and the optimization technique was adopted to obtain the appropriate critical current which could maximize the central magnetic field. Pancake windings with BSCCO-2223 HTS wire were wound on glass epoxy bobbin. 6 double pancake windings with 200 turns were used to construct a HTS magnet. Characteristics of the HTS magnet including the central magnetic field and the uniformity of the magnetic field were measured and compared with the results of calculation.

• Progress in Superconductivity and Cryogenics
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• v.17 no.3
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• pp.62-66
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• 2015

The cryostat is designed for the superconducting quadrupole magnets to be used in a heavy-ion accelerator facility. The main accelerator is superconducting linac, which can accelerate a $^{238}U$ beam to 200 MeV/u (Mega electron voltage per nucleon). The cryostat for the magnet employs an innovative design primarily driven by the requirement of the compactness, user-friendliness and reliability. Also, several ancillary requirements such as background field, space restriction due to the beam line and cryostat structure need technical attentions. The development of the cryostat for three quadrupole magnets in the in-flight fragmentation separator is presented in the paper. The concept of cryogenic design is reported and the amount of cryogenic load is estimated by a relevant analysis. The structure of the cryostat to endure the heavy iron yoke including three quadrupole magnets is presented. In addition, the design as well as the performance test of the support link for the cold mass is described.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.03b
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• pp.12-12
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• 2010

The hall probe measurement system was used to measure the critical current distribution of superconducting coated conductor. The system consists of reel to reel moving apparatus, 7 array hall probe, a rotary encoder and permanent magnet. The magnetic field profile across the width of superconducting coated conductor using Bean's critical state model was calculated. The effect of various parameters of the formulas on the magnetic field distribution and the effect of shape and size of artificial defects, which were formed on the surface of SmBa2Cu3O7-d(SmBCO) coated conductor using laser marking system, on the hall probe magnetic field signal of the hall probe measurement system was investigated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.149-150
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• 2005

According to the trend for electric power equipment of high capacity and reduction of its size, the needs for the new high performance electric equipments become more and more important. On of the possible solution is high temperature superconducting (HTS) power application. Following the successful development of practical HTS wires, there have been renewed activities in developing superconducting power equipment. HTS equipments have to be operated in a coolant such as liquid nitrogen ($LN_2$) or cooled by conduction-cooling method such as using Gifford-McMahon (G-M) cryocooler to maintain the temperature below critical level. In this paper, the dielectric strength of unfilled epoxy and filled epoxy in $LN_2$ was analyzed. The filled epoxy composite not only compensates for this fragile property but enhances its dielectric strength.

• Progress in Superconductivity and Cryogenics
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• v.24 no.1
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• pp.1-7
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• 2022

So far, large-scale scientific devices such as nuclear fusion tokamaks and high energy circular accelerators were constructed using high-current conductors made of metallic superconducting wires. Recently, as REBCO superconducting wires usable in high magnetic fields have been developed by several companies, researchesto apply high current cable type REBCO conductors to next-generation large superconducting magnets were also started. High critical currents of several kA or more in high magnetic fields have been successfully demonstrated on test samples of REBCO cable conductors by several research groups. In this review article, the main features and properties of the representative high current REBCO conductors such as CORC(Conductor On Round Core), TSTC(Twisted Stacked-Tape Cable) and RACC(Roebel-Assembled Coated Conductor), which are currently being developed at abroad are briefly introduced. Research activities of high-current density REBCO MHOS(Multi HTS layers on One Substrate) conductor at KERI, whose structure is different from other cable type REBCO conductors are also shortly introduced.