• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.931-933
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• 2000

Bi-2223 테이프의 실제 전력기기 응용측면을 고려할 때 테이프는 외부자계하에 놓이게 된다. 따라서 본 연구에서는 외부자계가 Bi-2223 테이프의 통전손실에 미치는 영향에 대해서 조사하였다. 비교적 작은 자계가 인가된 경우는 전압리드의 배역이 통전손실측정에 영향을 미쳤으나 비교적 큰 자계가 인가된 경우는 전압리드의 배열에 무관하다는 사실과, 전계와 통전손실은 외부사계가 증가함에 따라 각각 증가하였으며 비교적 큰 자계가 인가된 경우에 통선손실은 동저항 손실이 지배적이었으며. 외부자계가 작은 영역에서 통전손실은 동저항 이외의 또 다른 메카니즘에 의한 것으로 사려된다.

• 한국초전도ㆍ저온공학회논문지
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• 제7권1호
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• pp.47-50
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• 2005

The AC loss is an important issue in the design of the high temperature superconductor (HTS) power cables, which consist of a number of lli 2223 tapes wound on a former. In the cables, the tapes have different critical currents intrinsically. And they are electrically connected to each other and current leads. These make loss measurements considerably complex, especially for short samples of laboratory size. In this work we have prepared a multi-tape conductor composed of Bi-2223 tapes. The at losses of the conductor have experimentally investigated. The loss tests indicate that the effect of tapes critical currents on AC loss measurement in the multi tape conductor is negligible only if currents in the tapes flow uniformly Moreover, the measured tosses of the conductor are in good agreement with the sum of the transport losses in the tapes. However, in the case of non-uniform current distributions, the measured AC losses considerably depend on the current distribution parameter of the positioning of a voltage lead. Thus special cautions should be needed for the measurement of the true AC losses in the short power cable samples.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 학술대회 논문집
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• pp.213-215
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• 2003

This paper deals with the characteristics of a prototype solenoid for basic design of DC reactor type superconducting fault current limiter (SFCL). The prototype high-Tc Super-conducting (HTS) solenoid was manufactured with 4 stacked Bi-2223 tape. The critical currents were measured with respect to the number of stacks. In order to test the safety of HTS solenoid in quenched state, the transport tests of AC over-current were performed. These experimental results could be applied to the basic design of HTS DC reactor for SFCL effectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.817-818
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• 2006

A 2.0T class HTS conduction cooled magnet was designed. Designing of magnet shape was performed through two steps. First step is to find a basic cross section for minimize the amount of conductor used and second step to optimize the coil shape to satisfy the magnetic field homogeneity. The magnetic fields was analyzed with FEM and the critical current value of magnet was also expected with the result of field analysis and the Ic to B curve of Bi-2223 HTS tape.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.775-777
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• 2000

Superconducting racetrack coils are used in areas of generators, motors, wiggler magnets and so on. Especially now a days many advanced nations including U.S., Japan are developing high temperature superconducting(HTS) wire which has better performance than low temperature superconducting(LTS) wire. Most of HTS wires such as Bi-2223 are manufactured with PIT(Power In Tube Method) process, so the shape of the wire looks like tape different from LTS wire of round shape as normal conductors. Generally HTS racetrack coils are composed of a few partial double-pancake colis and then the double-pancakes are jointed each other according to their applications.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 추계학술대회 논문집
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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.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.735-737
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• 2003

A superconducting motor consisting of high temperature superconducting (HTS) rotor and air-core stator is under development in Korea Electrotechnology Research Institute. HTS motor was designed for having the rated power of 100hp at 1800 rpm. HTS field winding is composed of sixteen HTS race track shaped coils wound with stainless steel-reinforced Bi-2223 tape conductor by react and wind fabrication method. Nomex Paper was used for electrical insulation. Each of four magnet pole assemblies was constructed with four double pancake sub-coils, mechanically stacked and electrically in series. Four magnet assemblies were fixed on an aluminum support structure to make effective heat transfer. Critical current (Ic) of HTS field winding was 41A but minimum Ic of sub-coils was 35A at 77K and self field. Joule heat generated in HTS field winding was 2.11W at 77K and 35A.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.725-726
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• 2006

In large scale superconducting rotating machine, HTS field coils are constructed with many stacks of single or double pancake coils connected in series. In spite of its higher thermal stability, HTS field coil experiences some quench, which results in some part of burn-out in the field coils. Thus in the view point of the HTS rotating machine field coil design and testing, it was very important to predict the possibility of quench occurrence in the designed field coils. In this paper, a HTS racetrack coil constructed with two single pancake coils and one double pancake coil was tested in LN2 and cooling by GM refrigerator. It is wound using the Bi-2223 tape. The experimental details and results are presented in this paper.

• 한국초전도ㆍ저온공학회논문지
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• 제5권2호
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• pp.36-40
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• 2003

Inductive superconducting fault current limiter(SFCL) with DC reator rated on 6.6k $V_{rms}$/200 $A_{rms}$ has been developed in Yonsei University. The development of the DC reactor is the key technology in this type SFCL. This paper deals with the fabrication and characteristic test of the DC reactor. For the development of this magnet, the winding machine for high-Tc superconducting solenoid was manufactured. Using this machine, a large-scale HTS solenoid using Bi-2223 tape was fabricated successfully. This coil has 5 layers which are connected in series each other. The inductance of the DC reactor coil is 84mB. The cooling system was the sub-cooled nitrogen whose temperature is about 65K. The characteristic test of the coil was performed. The full quench current of this coil is about 490A.90A.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2000년도 KIASC Conference 2000 / 2000년도 학술대회 논문집
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• pp.69-72
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• 2000

AC losses in multifilamentary HTS tapes can be classified to hysteresis loss, coupling loss, and eddy current loss from the viewpoint of their generation mechanism. From the viewpoint of the major magnetic field component generating them, they can be classified to magnetization loss, transport loss, and total loss. Dividing superconductor to fine filaments, twisting filaments bundle and increasing transverse resistivity are effectively reduce magnetization loss and total loss when the external magnetic field is relatively large. Recently, twisted multifilamentary Bi 2223 tapes with pure silver matrix were fabricated and the reduction of magnetization loss was proved experimentally in the parallel magnetic field to the tape wide face. However, when the perpendicular magnetic field is applied, increasing transverse resistivity is required essentially to reduce the AC losses. The transverse resistivity was increased successfully by the introduction of resistive barrier between filaments.