• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2001.02a
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• pp.172-175
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• 2001

AC loss which is generated in an HTS wire varies with the direction of the external magnetic field. This paper calculates the AC loss in an HTS tape, where effects of the perpendicular direction of the magnetic field are considered. Brandt equation is used to calculate the loss by perpendicular magnetic field. In the calculation, current densities are varied along the variation of the magnitude of the external magnetic field. Results of calculation are compared with those of the conventional method.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.5
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• pp.473-477
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• 2005

A Bi-2223 tape has been developed for power applications such as a fault current limiter, a power cable and a superconducting magnetic energy storage system. In such applications, the Bi-2223 tape carries time varying transport current and in addition experiences time varying external magnetic field. It is well known that the external magnetic field not only causes magnetization loss in the Bi-2223 tape, but also drastically increases transport loss due to a so-called 'dynamic resistance' We developed an evaluation setup, which can measure transport loss in external at magnetic fields. Using this equipment, we measured the dynamic resistances for various amplitudes and frequencies of an external at magnetic field perpendicular to the face in the tape. Simultaneously we investigated the effect of an external ac field on transport loss with different experimental conditions. This paper describes test results ana discussions on correlation between the dynamic resistance and the transport loss for the Bi-2223 tape.

• Progress in Superconductivity and Cryogenics
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• v.19 no.1
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• pp.26-29
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• 2017

We studied the distribution of the current density and its magnetic-field dependence in GdBCO coated conductors with AC bias currents using low temperature scanning Hall probe microscopy. We selectively measured magnetic field profiles from AC signal obtained by Lock-in technique and calculated current distributions by inversion calculation. In order to confirm the AC measurement results, we applied DC current corresponding to RMS value of AC current and compared distribution of AC and DC transport current. We carried out the same measurements at various external DC magnetic fields, and investigated field dependence of AC current distribution. We notice that the AC current distribution unaffected by external magnetic fields and preserved their own path on the contrary to DC current.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.02a
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• pp.15-18
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• 2003

HTS(High Temperature Superconductor) tapes have dependence on critical characteristics such as electric, magnetic field and temperature. In order to confirm these effects, we examined the current transport characteristics of HTS tapes. First, after being fed DC and AC, the dependence of HTS tapes of 10cm on external magnetic field was investigated. On centeral region of HTS tape, about 1cm, external magnetic field was applied. Second, after applying DC of 50A to HTS tapes, we applied time variable magnetic field about 100mT and investigated the quench characteristics. Finally, AC, which is about 10 times of I$_{c}$, was applied to HTS tapes and over current characteristics were investigated. The data acquired in this study will be used as a source for the study of HTS cable conductor which is supposed to carry on.n.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1225-1227
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• 2005

A Bi-2223 tape has beer developed for power applications such as a fault current limiter, a power cable and a superconducting magnetic energy storage system. In such applications, the Bi-2223 tape carries time varying transport current and in addition experiences time varying external magnetic field. It is well known that the external magnetic field not only causes magnetization loss in the Bi-2223 tape, but also drastically increases transport loss due to a so-called "dynamic resistance". We developed an evaluation setup, which can measure transport loss in external at magnetic fields. Using this equipment, we measured the dynamic resistances for various amplitudes and frequencies of an external ac magnetic field perpendicular to the face in the tape. Simultaneously we investigated the effect of an external ac field on transport loss with different experimental conditions. This paper describes test results and discussions on correlation between the dynamic resistance and the transport loss for the Bi-2223 tape.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.6
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• pp.290-295
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• 2001

The transport loss of a Bi-2223 tape exposed to external magnetic fields was investigated. The results show that the transport loss is independent on voltage lead arrangements in case the magnetization loss is compensated. A serous increase of the transport loss due to external AC magnetic field is observed. The loss is described well by dynamic resistance loss in relatively high fields, but another mechanism than the dynamic resistance must be responsible for the increase of the loss in low fields. The transport loss is also dependent strongly on the orientation of the external fields.

• Progress in Superconductivity and Cryogenics
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• v.5 no.1
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• pp.97-101
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• 2003

When HTS tapes are used in power application, they are used by winding form, such as, a pancake and a solenoid. When AC current is applied to the coil, Ac magnetic field is generated in winding. This AC magnetic field acts as an external magnetic field and makes loss. In this paper the radial magnetic field component ($B_r$) and the axial magnetic field component ($B_z$) in a pancake and a solenoid were calculated by numerical analysis method and compare with measured value. AC losses of a short sample were calculated by Norris equation and n numerical analysis based on Brandt equation. AC losses of the pancake coil and the solenoid coil were also calculated.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.250-252
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• 1997

Phase difference of external magnetic field and self field is known to do an important role in the generation of the AC loss. This paper analize the AC loss of AC superconducting wire in combined action of an AC transport current and AC magnetic field for various phase differences.

• Progress in Superconductivity and Cryogenics
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• v.7 no.4
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• pp.10-13
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• 2005

Transport current and magnetic field which is generated by transport current make AC current - AC mag-netic field condition(AC-AC condition) in AC power application system using HTS tape. Therefore, characteristics of AC loss under the AC-AC condition are necessary to estimate AC loss of power device with accuracy such as HTS transformer. In this paper, we researched transport current loss, magnetization loss by perpendicular magnetic field and total loss which is represented as summation of both losses under the AC-AC condition in single HTS tape. As a result, magnetization loss showed increasing behavior under 65mT and decreasing behavior upper 65mT by influence of transport current. Transport current loss was increased continuously through out whole measurement ranges in the AC-AC condition. Total loss in HTS tape was dominated entirely by magnetization loss.

• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.71-73
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• 2006

AC loss on variation of external magnetic field is a very important factor in development of power applications. In this paper, we measured and compared AC loss of hybrid-multi stacked wire made of the combination of 1G wires and 2G wires and uniform-multi-stacked wire made of one type of wires, 1G wires or 2G wires. Measurement was performed using by the linked-picked coil method. As results, as the number of wires increase, AC loss per unit volume of both stacked wires in low external magnetic field is reduced. Also AC loss of 2G slacked wire is higher than that of 1G wire. AC loss per unit length of 2G stacked wire is less than that of 1G stacked wire. And AC loss of hybrid-multi stacked wire made of the combination of 1G wires and 2G wires was between uniform-multi-stacked wire made of 1G wires and 2G wires.