• Progress in Superconductivity and Cryogenics
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• v.9 no.1
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• pp.9-13
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• 2007

Coated conductor(CC) is recently in actively progress for the research and development, and its can be used various stabilizer lot the specific requirements for each application. Among various superconducting applications, coated conductor applied to superconducting fault current limiters(SFCLS) bypasses fault current to its stabilizer, where the surge is abruptly reduced ; thus, stainless steel, which has large resistivity can be a suitable stabilizer for SFCLS. Despite high n-value of the YBCO, CC stabilized with stainless steel did not effectively limit the first peak fault current. In the short circuit test results of AMSC's 344S, a half period delay was observed between the fault and the generation of resistance(60Hz). In this paper, we performed short-circuit experiments with stacked and unstacked CC and compared the test results to analyze effective fault current limiting characteristics. we compared time of the generated resistance as the fault current limiting characteristics and made the samples one is the stacked CC and the other is unstacked CC. These samples were used equal numbers of pieces of CC. In addition, comparison and analysis was made for the stacked structure by measuring fault current limiting characteristics with respect to thermal insulation by impregnating with epoxy resin.

• 한국초전도학회:학술대회논문집
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• 2009.07a
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• pp.126-126
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• 2009

• 한국초전도학회:학술대회논문집
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• 2009.07a
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• pp.116-116
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• 2009

• 한국초전도학회:학술대회논문집
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• 2009.07a
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• pp.117-117
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• 2009

• Progress in Superconductivity
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• v.6 no.1
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• pp.74-78
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• 2004

YBCO coated conductor is one of the most promising materials as a new generations wire especially for practical power applications. In this work, $YBa_2$$Cu_3$$O_{7}$ -$\delta$/(YBCO) coated conductors (CC) were deposited by pulsed laser deposition (PLD) from buffer layers to superconducting layer on hi-axially textured metal tape. The oxide multilayer buffered substrate of architectures of $CeO_2$/$YSZ/Y_2$$O_3$ was fabricated by PLD at steady status. Then YBCO layer was deposited on RABiTS substrate by stationary and reel-to-reel (R2R) continuous process and we compared with deposition conditions of both processes. The degree of texture of each layer was investigated using X-ray diffraction including $\theta$-2$\theta$ scans, $\omega$-scans and $\Phi$-scans analysis. Their surface morphology was observed by scanning electron microscopy (SEM). The FWHM of the X-ray $\Phi$-scans and $\Phi$-scans indicated that YBCO and buffer layers closely replicate the in-plane and out-of-plane texture of metal tape. Critical current (Ic) at 77 K, self-field of 75.8 A/cm-width, critical temperature (Tc) of 85 K, and critical current density (Ic) of 3.7 MA/$\textrm{cm}^2$ were measured from coated conductor deposited by stationary process. And coated conductor deposited by R2R continuous process had Ic of 57.5 A/cm-width, Tc of 86.5 K and Jc of 2.0 MA/$\textrm{cm}^2$. The film also exhibits a homogeneous and dense surface morphology.

• Progress in Superconductivity
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• v.10 no.2
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• pp.149-154
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• 2009

We measured and analyzed the quench development in coated conductor(CC) tapes. The CC was grown on hastelloy substrates and has an Ag protection layer. The tapes were subjected to simulated AC fault currents for quench development measurement. They were immersed in liquid nitrogen during the experiment. The quench resistance increased rapidly first, and the increase slowed down afterwards. It increased linearly with applied voltage at lower voltages, and depended less strongly on applied voltage at higher voltages. The resistance was compared with that of Au/YBCO films grown on sapphire substrates, and found to increase more monotonously than the latter. Data were analyzed quantitatively with the concept of heat transfer within the tape and the surrounding liquid nitrogen. A heat balance equation was derived and solved, taking into consideration temperature dependence of thermal parameters of the tapes. Solutions, together with values of thermal parameters taken from the literature, explained the data well. Cooling by liquid nitrogen affected the quench development considerably at lower applied voltages. Dependence on applied voltages could be also understood quantitatively.

• Progress in Superconductivity and Cryogenics
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• v.15 no.2
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• pp.24-28
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• 2013

In this study, the homogeneity of critical current, $I_c$, along the lengthwise direction in the coated conductor (CC) tape under uniaxial tension was investigated using a multiple voltage tap configuration. Initially, a gradual and homogeneous $I_c$ degradation occurred in all subsections of the tape up to a certain strain value. This was followed by an abrupt $I_c$ degradation in some subsections, which caused scattering in $I_c$ values along the length with increasing tension strain. The $I_c$ degradation behaviour was also explained through n-value as well as microstructure analyses. Subsections showed $I_c$ scattering corresponding to damaged areas of the CC tape revealed that transverse cracks were distributed throughout the gauge length. This homogeneous $I_c$ degradation behaviour under tension is similar with the case under torsion strain but different with the case under hard bending which were previously reported. This behaviour is also different with the case using Bi-2223 HTS tapes under tension strain.

• Progress in Superconductivity and Cryogenics
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• v.9 no.1
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• pp.47-52
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• 2007

This paper presents characteristics analysis of persistent current switch(PCS) system on a small scale by using YBCO coated conductor(CC). A high temperature superconductor(HTS) PCS system mainly consists of a PCS, a HTS magnet load and a magnet power supply(MPS). To design the optimal heater triggering switch. the three-dimensional heat conduction model was analyzed by finite element method(FEM). The electrical equivalent model considering the n-value of CC was applied to analyze current decay during persistent current mode. In the experiment and simulation, the heater was applied with a current of 0.43A and the current was ramped up to 10A and 20A with 0.2A/s. Finally, experimental results of the HTS PCS system have been compared with the theoretical results. It has been concluded that flux creep can not influence the results because the operating current was 40% of critical current and optimal sequential operation of the PCS system is indispensable to enhance its performance.

• Progress in Superconductivity and Cryogenics
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• v.8 no.3
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• pp.9-12
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• 2006

Batch type co-evaporation EDDC (Evaporation using Drum in Dual Chambers) system was recently manufactured to fabricate 100m - long SmBCO superconducting coated conductor. As a preliminary study before the fabrication of long tape. short CC samples have been fabricated using the EDDC system and their crystal texture and $I_c$ properties were investigated. $1.2 {\mu}m$-thick SmBCO layers were deposited on $CeO_2/YSZ/CeO_2$ buffered Ni-W tapes. $I_c$ of 128A/cm-w and corresponding $J_c$ of $1.1 MA/cm^2$ at 77K in self-field were obtained for SmBCO CC tape. In-field property of SmBCO CC was confirmed to be better than that of YBCO deposited by PLD.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.894-895
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• 2011

본 논문은 5 MJ의 저장용량을 가지는 초전도 에너지 저장장치용(Superconducting Magnetic Energy Storage System, SMES) 마그넷의 설계에 관한 연구 결과이다. 마그넷의 설계에 사용된 초전도 선재는 2세대 고온초전도 선재인 YBCO CC이고, 초전도 선재의 냉각방식은 냉동기를 이용한 전도냉각으로 마그넷의 운전온도는 14 K 이다. SMES용 마그넷은 테이프형태를 가지고 있는 초전도 선재의 형태를 고려하여 팬케이크 코일로 권선된 모듈코일을 이용하여 토로이드 형태의 마그넷 구조로 설계되었다. 설계를 통해 마그넷의 저장에너지와 초전도 선재의 사용량, 자속밀도 분포 등을 확인하였다.