• 한국초전도ㆍ저온공학회논문지
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• 제7권4호
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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.

• 한국전기전자재료학회논문지
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• 제14권3호
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• pp.251-256
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• 2001

Bi-2223 tapes have been developed for low-field power applications at liquid nitrogen temperature. When the Bi-2223 tapes are used in an application such as a power transmission cable or a power transformer, they are supplied with an AC transport current simultaneously. AC loss taking into account such real applications is a crucial issue for power applications fo the Bi-2223 tapes to be feasible. In this paper, the transport losses for different AC current levels and arrangements of the neighboring tapes have been measured in a 1./5 m long Bi-2223 tape. The significant increase of the transport losses due to neighboring tape's AC currents is observed. An increase of the transport losses caused by a decrease of the Bi-2223 tape's critical current is a minor effect. The measured trasprot losses could not be explained by a dynamic resistance loss based on DC voltage-current characteristics in combination with the neighboring tape's AC currents.The trasport losses do not depend on the frequency of the neighboring tape's AC currents but is arrangements in the range of small current especially.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권6호
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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.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전력기술부문
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• pp.96-100
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• 2001

Bi-2223 tapes have been developed for low-field power applications at liquid nitrogen temperature. When the Bi-2223 tapes are used in an application such as a power transmission cable or a power transformer, they are supplied with an AC transport current and exposed to an external magnetic field generated by neighboring tape's AC currents simultaneously. AC loss taking into account such real applications is a crucial issue for power applications of the Bi-2223 tapes to be feasible. In this paper, the transport losses for different AC current levels and arrangements of the neighboring tapes have been measured in a 1.5 m long Bi-2223 tape. The significant increase of the transport losses due to neighboring tape's AC currents is observed. An increase of the transport losses caused by a decrease of the Bi-2223 tape's critical current is a minor effect. The measured transport losses could not be explained by a dynamic resistance loss based on DC voltage-current characteristics in combination with the neighboring tape's AC currents. The transport losses do not depend on the frequency of the neighboring tape's AC currents but its arrangements in the range of small current especially.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2008년도 High Temperature Superconductivity Vol.XVIII
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• pp.75-75
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• 2008

• 한국전기전자재료학회논문지
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• 제18권5호
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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.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권1호
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• pp.10-14
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• 2001

The superconducting transmission cable is one of interesting part in power application using high temperature superconducting wire. One important parameter in HTS cable design is transport current sharing because it is related with current transmission capacity and loss. In this paper, we calculate self inductances of each layer and mutual inductances between two layers from magnetic field energy, and current sharing of each layer for 4-layer cable using the electric circuit model which contain inductance and resistance (by joint and AC loss). Also, transport current losses which are calculated by monoblock model and Norris equation are compared. As a results, outer layer has always larger transport current than inner layer, and current capacity of each layer is largely influenced by resistance per unit cable length. As a conclusion, for high current uniformity and low AC loss, we have to decrease inductances themselves or those differences.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.56-58
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• 2007

AC transport current losses is an important factor in the development of superconducting tapes and superconducting power applications. In this paper we compared measurement, calculation and Norris equation of AC transport current loss in BSCCO single and multi stacked wire. And present a distribution flux density and current density in the HTS single wire and multi stacked wire. The result of Measurement and calculation of Ac transport current loss show that the same. And show that HTS characteristic of inside HTS wire.

• 한국초전도ㆍ저온공학회논문지
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• 제11권3호
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• pp.31-34
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• 2009

An HTS power cable is generally composed of 2 layers for conducting and 1 layer for shielding. For the analysis of AC loss of an HTS power cable, 2-dimensional magnetic field analysis is carried out. The magnetization loss in HTS cable core was calculated, and the transport current loss was obtained from the monoblock equation and the elliptical Norris Equation. And the total AC loss of the cable was expected by the sum of magnetization loss and transport current loss. The variation of ac loss with respect to the gap and uncertain factor between the superconducting tapes was investigated, and the ac loss of 22.9kV/50MVA high-Tc superconducting power cable was calculated. These results well agree with those of experiment.

• 한국초전도ㆍ저온공학회논문지
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• 제14권2호
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• pp.16-19
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• 2012

The influence of current distribution on the transport current loss in vertically stacked high-$T_c$ superconductor (HTS) tapes was evaluated. AC loss was analyzed as a function of current distribution by introducing a current distribution parameter through a numerical method (finite element analysis). AC loss under non-uniform current distribution is always higher than that for a uniformly distributed transport current in a conductor. Although the effect of non-uniformity is relatively insignificant in low transport current, AC loss increases substantially in high transport current regions as non-uniformity is enlarged. The results verify that non-uniform current distribution causes extra loss by examining the cross-sectional view of current densities in stacked conductor.