• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.804-806
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• 2000

동일한 임계전류 특성을 갖는 Bi-2223 테이프에 전력기기의 실제 응용에서 발생되는 큰 사고전류를 고려한 임계전류보다 큰 과임계전류를 흘렸을 때 테이프의 온도상승 및 저항 특성을 중요한 인자에 대해 조사하였다. 냉각이 좋은 즉 비절연 테이프의 경우 온도상승은 없고, 표피효과에 의한 저항의 증가도 없고, 특히 비절연 테이프의 경우 과도 및 정상 상태 저항이 동일한 반면 절연 테이프의 경우 매우 상이하고, 전기절연 길이를 전압탭보다 길게만 해주면 길이에 무관하게 온도상승 및 저항이 동일하였으며 마지막으로 모재의 저항율이 상이하여도 임계전류만 동일하면 온도상승 및 저항은 유사함을 알 수 있었다.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.340-342
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• 1998

This paper presents the ac losses simulation in the rotor having an high-Tc superconducting field winding using Ag sheathed Bi-2223. The analysis was conducted with an equivalent model of the high-Tc superconducting motor under transition condition during the load that varies from 250watt to 500watt. The simulation results show that the transient state lasts for about 2 seconds, and the ac losses decreased exponentially from the initial value above 2 watts.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05a
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• pp.17-22
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• 2003

HTS superconducting tapes are now commercially available for practical applications such as magnets and cables. Since superconductors in such applications are subjected to high mechanical loads that can significantly degrade the superconducting properties, mechanical properties and the strain tolerance known as the strain effect on superconducting properties are needed to be estimated for developing superconducting devices. The progress in technology achieved in the field of strain effect evaluation on the critical current of HTS tapes in various deformation modes is discussed in this study.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.10a
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• pp.274-277
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• 2003

Critical current(Ic) degradation of HTS tapes after bending is one of the hottest issues in HTS development and application studies. Many people are measuring Ic degradations for effect of bending radius. However even if the bending radius is larger than the breaking radius a HTS tapes can be damaged by repetitive bending, which is unavoidable in the winding processes. Therefore, We studied the Ic degradation after repetitive bending. at 77K with self-field, of Bi-2223 tapes processed by "Powder-in-Tube" technique, which was made by America Superconductor Corporation(AMSC) and superconductiing tapes that strain is imposed measured critical current by temperature difference of L$N_2$ and normal temperature. Like this, critical current could measure that degradation about 1~3％ by temperature difference. These results will amount the most important basis data in power electric machine of superconductivity cable, magnet, etc that winding work is require.

• Progress in Superconductivity and Cryogenics
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• v.19 no.3
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• pp.1-7
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• 2017

It is required to reduce the cost of superconducting cable to realize a superconducting DC power network that covers a wide area in order to utilize renewable energy. In this paper a new concept of innovative cable is introduced that can enhance the current-carrying capacity even though the same superconducting tape is used. Such a cable can be realized by designing an optimal winding structure in such a way that the angle between the tape and magnetic field becomes small. This idea was confirmed by preliminary experiments for a single layer model cable made of Bi-2223 tapes and REBCO coated conductors. Experiments of three and four layer cables of practical sizes were also done and it was found that the current-carrying capacity increased as theoretically predicted. If the critical current properties of commercial superconducting tapes are further improved in a parallel magnetic field, the enhancement will become pronounced and this technology will surely contribute to realization of superconducting DC power network.

• Proceedings of the KIEE Conference
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• summer
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• pp.1121-1123
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• 2004

Characteristics of the break down current of HTS tape with different insulator are described. The various insulators are utilized for enduring the high voltage in superconducting power devices. The break down current of HTS tape largely depends on insulators wound round HTS tape. In this research, The break down currents of Bi-2223 tape, which is widely used for superconducting power devices are tested and discussed. It is expected that results from this study can be utilized as basic data in designing superconducting power devices.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.452-455
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• 2000

Superconducting power cable is one of the most promising energy application of high-T$_{c}$ superconductors (HTS). A prototype HTS cable have been constructed multi-layer cable using Bi-2223 tape and tested. The AC transport losses under self field were investigated at 77K on the 19 filamentary tape and multi-layer HTS cables. And we carried out numerical analysis using bean model. The result shows that the total transport current of HTS cable in L$N_2$ was 475[A], and transport current passed through almost the outer layer (2-layer). Also, AC transport losses in outer layer of HTS cable was proportion to I$^2$ and higher than losses of inner layer. In case of Ip=Ic, calculated numerical loss density was concentrated on the edge of tape and most of loss density in cable was distributed outer layer more than inner layer. As magnetic distribution was concentrated on outer layer.r.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.05a
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• pp.34-37
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• 1994

.In this study, we measured Ic depending on a curvature radios of High Tc superconducting tapes which were made of a single wire, two and three WIT(wire in tube). Wires are manufactured by the process of press ins and sintering (150h, at 845$^{\circ}C$ ) for the growth of 2223 high Tc Bi superconducting phase. We know that Ic of a single wire decrease with reduction of a curvature radius. The maximum Ic of 2 WIT wire is 2.54 (A) and have a better characteristic than a single wire (0.89 A) at a curvature radius 75mm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.244-245
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• 2007

Specially, High Temperature Superconducting power-transmission cable(HTS cable), 3-phase 100m long, 22.9kV class HTS power transmission cable system have been developed by Korea Electrotechnology Research Institute (KERI) and LS cable Ltd. that is one of 21st century frontier project in Korea. This cable was installed in KEPCO(Go-chang) testing site. In case of manufacturing HTS cable, superconducting joint is very important because they need very long tapes. Therefore, this paper gives some investigation of AC Loss in joined HTS tape by using several joint methods. Finally, this paper was shown background data for the form of HTS cable joint.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.939-940
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• 2007

다수본의 Bi-2223테이프로 구성되는 초전도전력케이블에서 발생되는 교류손실은 케이블의 효율을 저하시킬 뿐만 아니라 냉동기비용 증가로 인한 기존 케이블과의 가격경쟁에서 경제성을 저하시키는 주된 요인으로 작용하기 때문에 이의 상용화에 앞서 교류손실에 대한 정확한 규명이 되어야 한다. 그러나 다수본으로 구성되는 고온초전도전력케이블의 교류손실을 올바르게 평가하는 것은 테이프의 상이한 임계전류, 전압리드의 배열, 전류분포의 불균일성 및 인접한 테이프에 흐르는 전류위상 상이 등 복잡한 영향인자 때문에 매우 난해하다. 이와 같은 교류손실 평가와 관련된 복잡한 문제들을 규명하기 위해 다수본의 고온초전도도체 샘플을 제작하였으며 그 손실 특성을 실험적으로 조사 및 검토 하였다. 그 결과 다수본 고온초전도도체의 측정된 교류손실은 Monoblock모델 이론값 및 다각형모델에 근거한 수치해석 결과와도 상이함을 알 수 있다.