• 한국초전도ㆍ저온공학회논문지
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• 제11권1호
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• pp.49-54
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• 2009

This paper presents the numerical simulation results on the moving type electrodynamic suspension (EDS) simulator and static type EDS simulator using high-Tc superconducting (HTS) levitation magnet. The levitation force of the EDS system is formed by the reaction between the moving magnet and the fixed ground conductor. The possible two ways to simulate the EDS system were simulated in this paper by using finite element method (FEM). The first way was the moving type simulator which consists of the fixed HTS magnet and the moving ground conductor. The second way was the static type simulator which consists of the fixed magnet, the fixed ground conductor and the ac current supply system. To verify the characteristics of high speed EDS system with the moving type simulator heavy, large and fast moving ground conductor is needed. The static type simulator can get the characteristics of the high speed EDS system by applying equivalent ac current to velocity, therefore it does not need large moving part. The static type EDS simulator, which can consist of an HTS magnet, the fixed ground conductor(s), an AC power supply and the measuring devices, also test the effect of the shape of the ground conductor easily. The plate type ground conductor made stronger levitation force than ring type ground conductor. Although the outer diameter 335 mm ring type ground conductor (Ring3) was larger than the outer diameter 235 mm ground conductor (Ring2), the levitation force by Ring2 was stronger than that by Ring3. From the calculation results on this paper, the consideration of the magnetic flux distribution according to the levitation height should be included in the process of the ground conductor design.

• Progress in Superconductivity
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• 제3권1호
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• pp.115-119
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• 2001

For the fabrication of HTS power cable, multifilamentary Bi-2223/Ag tapes have been prepared using the powder-in-tube (PIT) process. After final heat treatment, these tapes have $I_{c}$ value of 43A, and$ J_{c}$ value of $28,000A/\textrm{cm}^2$(77K, 0T). Prototype 1000A class multistrand conductor(length~1m) was fabricated using these tapes(length~300m). This multistrand conductor was impregnated with low-temperature epoxy. The transportation properties of prototype 1000A class multistrand conductor has been evaluated at 77K, and yielding a current capacity up to 1200A.A.A.

• 한국초전도ㆍ저온공학회논문지
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• 제15권1호
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• pp.29-34
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• 2013

AMR (Active Magnetic Regenerative) refrigerators require the large variation of the magnetic field and a HTS magnet can be used. The amount of AC loss is very important considering the overall efficiency of the AMR refrigerator. However, it is very hard to estimate the precise loss of the HTS magnet because the magnetic field distribution around the conductor itself depends on the coil configuration and the neighboring HTS wires interact each other through the distorted magnetic field by the screening current Therefore, the AC loss of HTS magnet should be calculated using the whole configuration of the HTS magnet with superconducting characteristic. This paper describes the AC loss of the HTS magnet by an appropriate FEM approach, which uses the non-linear characteristic of HTS conductor. The analysis model is based on the 2-D FEM model, called as 'magnetic field formulation and edge-element model', for whole coil configuration in cylindrical coordinates. The effects of transport current and stacked conductors on the AC loss are investigated considering the field-dependent critical current. The PDE model of 'Comsol multiphysics' is used for the FEM analysis with properly implemented equations for axisymmetric model.

• 한국초전도ㆍ저온공학회논문지
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• 제20권1호
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• pp.19-22
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• 2018

The thermal and electrical properties of the conductor are critical parametersfor the design and optimization of the superconducting magnet. This paper presents simulation code to analyze electrical and thermal stability characteristics of the second generation (2G) high-temperature superconductor (HTS) by varying copper stabilizer thickness. Two types of commercial 2G HTS coated conductor tapes, YBCO and GdBCO were used in this study. These samples were cooled by Liquid Nitrogen ($LN_2$) having boiling at 77.3 K and an equivalent electrical circuit model for them is choosen and analysed in details. Also, an over-current pulse test in which a current exceeding a critical current was performed. From the simulation results, the influences of the copper stabilizer thickness on the stability characteristics of these samples are presented.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.290-291
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• 2008

Recently High Temperature Superconductor(HTS) Tape is limelight of the applied superconducting machines. Mainly used superconducting tape are BSCCO tape and YBCO coated tape. These superconducting tape are applied such as SMES, superconducting generator and MAGLEV. Actually superconductor tape's experimental gauge is short. For this reason, experiment was conducted. Firstly length of 50cm BSCCO, YBCO Coated conductor@Cu and YBCO coated conductor@sus are prepared. and flow the over-current. Secondly, BSCCO and Coated conductor connected with lenth of 25cm and flow the over-current. Coupled line of HTS tape was compared with single line of HTS tape and these overcurrent characteristics was investigated.

• 전기학회논문지
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• 제59권10호
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• pp.1748-1753
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• 2010

This paper suggests an improved technique to establish the modeling regarding steady and transient state on three phase-in one cryostat type HTS(High Temperature Superconducting) cable. The proposed modeling is established using EMTP/ATPDraw and TACS and MODELS provided by that. It has higher accuracy than the conventional method, as the actual HTS cable is modelled. Steady and transient state analysis performed by EMTP/ATPDraw calculate the current of conductor, shield and former, respectively. In case of the transient state modeled quench state occurred by a single line-to-ground fault, current of conductor shield and former are also calculated, respectively. Especially, various fault resistances and angles are considered to improve the reliability during transient state analysis. Analysis results reveal that the proposed technique improves the accuracy of modeling.

• 한국초전도ㆍ저온공학회논문지
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• 제13권2호
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• pp.5-8
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• 2011

This paper shows results of a design work of a program that is to develop a large power single phase high temperature superconducting (HTS) transformer. The program forms a part of a national project in Korea. A target of the design work is an HTS power transformer with rated voltages of 154 kV/22.9 kV and material for windings is supposed to be coated conductor. The design results presents in this paper will include: 1)HTS winding structures for high voltage in liquid nitrogen, 2)design result of continuously transposed coated conductor (CTCC), 3)conceptual design of high voltage bushings, 4)cooling system. A feasibility study will succeed to this design work for construction of a prototype HTS power transformer with capacity/voltage of 33 MVA/154 kV.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.973-975
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• 2003

Uniform current distribution among conductor layers in HTS cables using IPTS (inter-phase transformers) was proposed. Conventional methods for current distribution, in which resistors are inserted to conductor layers, causes additional loss. In contrast, IPTS, which use magnetic coupling, make it possible that the current in parallel circuits is distributed uniformly with any load, and minimize the loss. In this study, IPTS were designed and fabricated for examination of uniform current distribution in the conductor layers of HTS cables. The ITP was designed through calculation of its impedance that can cancel the inductance of the conduction layers.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권2호
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• pp.83-88
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• 2006

AC loss is one of the main research area in AC power application using high temperature superconductor(HTS), such as HTS transformer, HTS current limiter and HTS cable, because it is closely related to efficiency, economic estimation and design of power device. A lot of research for various arrangements of HTS tapes have been performed to increase a capacity of transport current because single HTS tape can not satisfy the demanded current capacity in HTS power application. In this paper, we studied magnetization loss by different several arrangements of BSCCO tapes such as Edge-to-Edge type, Face-to-Face type and Matrix type through numerical analysis by 2D-FEM and measurement. As a result, we got the result that the magnetization loss of Face-to-Face type arrangements was lower than those of other arrangement types under the conditions of the same stacking number. We think that the result was due to shield effect by demagnetization of adjacent HTS tapes which are located face to face.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2001년도 High Temperature Superconductivity Vol.XI
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• pp.11-11
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• 2001