• Progress in Superconductivity and Cryogenics
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• v.13 no.4
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• pp.26-29
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• 2011

In a High temperature superconducting (HTS) tape with high aspect ratio, the magnetic field applied to the HTS tape can be different considerably within the HTS tape. The current distribution in the HTS tape is generally non-uniform because the current distribution is strongly dependent on the applied magnetic field. Non-uniform current distribution in a HTS tape has not been properly considered when the critical current has been estimated. This paper shows the calculation of critical current of a HTS magnet consisting of pancake windings. Non-uniform distribution of current in the HTS tape is considered during the calculation of the critical current. Results of calculation show the current concentrated in the middle part of the HTS tape which is used for one pancake winding.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.903-905
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• 2002

According to the improvement of the HTS wires performance, several types of HTS superconducting machines, such as, transformer, motors, current limiters, and transmission cables are being developed. Degradation of the critical current in HTS tape owing to external field is very important subject in developing the HTS machines. Considering that stacked HTS tapes are widely used to develop the large HTS machines, the critical current characteristics of stacked HTS tapes in external field need to be examined. In this paper, we present critical current characteristics of 4-stacked HTS tapes which are exposed to the external field. HTS tape with critical current of 4-stacked HTS tape. Test results prove that four times critical current of single HTS tape is smaller than critical current of stacked HTS tape in high external field.

• 한국초전도학회:학술대회논문집
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• v.10
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• pp.308-310
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• 2000

일반적으로 Bi계 고온초전도선재(HTS Tape)는 저온초전도선재(LTS Tape)에 비해서 비열이 수백 배 이상 크므로 열적으로 상당히 안정한 성격을 가진다. 그러므로 이러한 HTS Tape를 TQ(Thermal Quench)시켜주는 일은 매우 어렵게 되는데, 일반적으로 HTS Tape를 이용한 초전도응용 분야에서 TQ를 이용한 스위칭 동작이 매우 중요하므로, 응응에 앞서 이에 관한 연구가 반드시 이루어져야 할 것이다. 본 연구에서는 Bi-2223 Short Sample의 TQ 특성을 실험하여 온도특성과 전압특성 등을 비교하였으며, 또한 이론적으로 HTS Tape를 TQ시켜주기 위한 열량과 실제 실험에서 사용된 열량의 값을 비교하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.284-285
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• 2005

Bi-2223 High-Temperature Superconducting(HTS) tape is one of the most widely used HTS tape for power application. Characteristics of the over current of HTS tape with different sheath are described. This paper presents the basic properties such as temperature and resistivity rise of the Bi-2223 HTS tape which is exposed to the over current. It is expected that results from this study can be utilized as basic data in designing superconducting power devices.

• Progress in Superconductivity and Cryogenics
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• v.2 no.1
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• pp.36-39
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• 2000

The main issues for the power application of high Tc superconducting tape are lower AC loss and higher stability conditions. HTS tape has large stability margin by high heat capacity of superconductor itself and high temperature margin. But, it can be damaged by continuous heat generation at quench point, because normal zone propagation velocity by generating heat is very low. Here, we analyze the quench propagation characteristics using finite element method for BSCCO-2223 HTS tape.

• Progress in Superconductivity and Cryogenics
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• v.1 no.2
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• pp.15-19
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• 1999

For large scale applications of high temperature superconductor (HTS) such as transmission cables, motors and generators, long length of flexible HTS conductor is required. Currently, Bi-2223 HTS tape is capable of being fabricated in longer than 100 m length by industrial processes. In this study, we fabricated 100 m 19 filamentary Bi-2223 ($Bi_{1.8}Pb_{0.4}Sr_2Ca_2O_{10+x}$) HTS tape by PIT (Power in Tube) process. Critical current(IC) of this long length tape was measured 18.5 A at 77K, self field. Critical current of 100 m length tape was mainly resulted from the increase of inhomogeneity in oxide from the increase of inhomogeneity in oxide layer. Engineering critical current (Je=Ic/total tape cross-section area) that is important factor for practical applications and fabrication cost was measured 2.2 kA/cm2.

• Progress in Superconductivity and Cryogenics
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• v.17 no.2
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• pp.50-53
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• 2015

The properties of High Temperature Superconducting (HTS) tapes are progressing, as HTS tapes evolve from 1st generation to 2nd generation. This paper presents design and construction of a 2nd generation HTS magnet consisting of two nested GdBCO and YBCO pancake coils. Two HTS tapes of different widths were used to wind the HTS nested magnet. Considering that a higher magnetic field is applied to the inner magnet than to the outer magnet, 12 mm GdBCO tape was used for winding the inner magnet, which consisted of four single pancake windings. Eight double pancake windings wound with 4.4 mm YBCO tapes were used for the outer magnet. The test results show that the central magnetic field of the HTS nested magnet was 920 mT. The measured critical currents of the inner and outer magnet at 77K were 80.8 A and 32.6 A, respectively.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 1999.02a
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• pp.10-13
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• 1999

For large scale applications of high temperature superconductor(HTS) such as transmission cables, motors and generators, long length of flexible HTS conductors is required. Currently, HTS tape that is capable of being fabricated in long length by industrial processes is the Bi-2223 HTS tape. In this study, we fabricated 19 filamentary Bi-2223($Bi_{1.8}$$Pb_{0.4}$$Sr_{2}$$Ca_{2}$$Cu_{3}$$O_{10+X}$) HTS tape with 100m length by PIT(Powder In Tube) process. Critical current(Ic) of this long length tape was measured 18.5 A at 77 K, self field and short sample Ic is 32.5 A at the same condition. Critical current of 100m length tape was decreased by about 1/3 compared to that of short tape. This was mainly resulted from the increase of non homogeneity in oxide layer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.69-72
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• 2004

In order to use HTS tape on electric power applications, such as cable, motor, transformer, fault current limiter, a long length of HTS tape with a good uniformity of critical current is inevitable. The longer length of HTS tape, the wider in the range of application and the lower cost of HTS tape. In this study three long length Bi-2223/Ag tapes(268m, 253m and 187m) were fabricated. Critical current uniformity along the length was greatly improved through the optimization of cold deformation and thermo-mechanical process. Average critical current of the tapes was 63.2 A, 54.6 A and 64.2 A, respectively Critical tensile strength and critical bending radius (77 K, 5 % Ic degradation) was 135 MPa and 56 m, respectively.

• Progress in Superconductivity and Cryogenics
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• v.17 no.3
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• pp.47-50
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• 2015

The high temperature superconducting (HTS) magnet has been developed for the high magnetic field applications such as NMR, MRI and other industrial machinery. In designing process of these HTS magnets, the accurate estimation on the critical current (Ic) is essential to predict and secure the electromagnetic performance. The critical current of 2G HTS tape has anisotropic Ic degradation characteristics with the application of magnetic field - angular dependency of critical current. It is known that the perpendicular magnetic field to the face of HTS tape makes dominant degradation on the critical current for conventional 2G HTS tape. However, recently developed 2G HTS tape has more complex characteristics due to the artificial pinning center. Therefore, the method for Ic estimation reflecting such characteristics of 2G HTS tape needs to be devised. The method considering the angular dependency is introduced in this paper. And the result of newly devised method is compared with that of previous method.