• Progress in Superconductivity
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• 제6권1호
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• pp.46-51
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• 2004

We fabricated a resistive type superconducting fault current limiter (SFCL) of 3-phase $6.6 kV_{rms}$ / rating, based on YBCO thin films grown on sapphire substrates with a diameter off inch. Each element of the SFCL was designed to have the rated voltage of $600 V_{rms}$ $/35A_{rms}$. The elements produced a single phase with 8${\times}$6 components connected in series and parallel. In addition, a NiCr shunt resistor of 23 $\Omega$ was connected in parallel to each of them for simultaneous quenches between the elements. Prior to investigating the performance of the 3 phase SFCL, we examined the quench characteristics for 8 elements connected in series. For all elements, simultaneous quenches and equal voltage distribution within 10% deviation from the average were obtained. Based on these results, performance of the SFCL for single line-to-ground faults was investigated. The SFCL successfully limited the fault current of $10 kA_{ rms}$ below 816 $A_{peak}$ within 0.12 msec right after the fault occurred. During the quench process, average temperature of all components did not exceed 250 K, and the SFCL was totally safe during the whole operation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.85-86
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• 2008

This paper analyzes the improvement of the power quality by the reduction of the inrush current. We analyze the existing methods and simulate the segragated point-on-wave closing method selected as the proper method. And we attempts to use the resistive type Superconducting Fault Current Limiter(SFCL) to reduce the transformer inrush current. We simulate the various insertion resistances and analyze the voltage drop. All simulation are performed by EMTP. The simulation results show the validity and effectiveness of a SFCL application and the segragated point-on-wave closing method to reduce the inrush current and improve the power quality.

• 조명전기설비학회논문지
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• 제22권1호
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• pp.113-117
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• 2008

본 논문에서는 결선방향에 따른 자속구속형 전류제한기의 전류제한 및 회 특성에 대해 분석하였다. 자속구속형 초전도 한류기는 초전도 소자와 직렬로 연결된 2차 권선과 병렬로 연결된 1 2차 권선으로 구성되어 있다. 1 2차 권선의 결선방향에 따른 가극 결선과 가극 결선을 갖는 자속구속형 전류제한기를 저항형 전류제한기와 비교하여 분석하였다. 전류제한 및 회복특성은 1 2차 권선의 결선방향에 의존한다. 가극 결선을 갖는 자속구속형 전류제한기의 퀜치시간은 감극 결선이나 저항형 전류제한기보다 더 빠르다는 것을 확인하였다. 초전도 소자에서 소비되는 에너지는 $W= VIt=I^2Rt$으로 표현할 수 있다. 결선 방향에 따라 초전도 소자에서 소비되는 에너지의 차이는 초전도 소자에서 부담하는 전압의 차이 때문이라는 것을 확인할 수 있었다.

• Progress in Superconductivity
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• 제3권2호
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• pp.252-256
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• 2002

We studied YBCO films for current limiting of the resistive type which utilizes a transition from superconducting to normal state caused by exceeding critical current. The films were deposited on sapphire substrates and covered by gold top layer. The current limiting element consists of 2 mm wide YBCO stripes connected in series. A serious problem in using YBCO films for current limiting is inhomogeneities caused by imperfect manufacturing. Therefore simultaneous quench is a difficult problem when elements for current limiting are connected in series. So some researchers have recently proposed using magnetic field and heating for simultaneous quench. We have measured extended exec trim field-current density(E-J) characteristics for current limiting elements of YBCO films in applied magnetic field of 0 - 130 mT. And we have investigated quench characteristics in current limiting elements and between elements of YBCO films in applied magnetic field. The result of the experiments show that the presence of applied magnetic fields induces uniform quench distribution fur the stripes in element at $50V_{rms}$, otherwise non-uniform quenches were observed. And simultaneous quenches between elements were investigated at $150V_{rms}$. We suggest that suppressing the critical current by increased fields due to fault current effectively forced the stripes of higher $J_{c}$(0) to quench, resulting in equalizing quench times.s.s.s.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.188-189
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• 2006

The flux-lock type superconducting fault current limiter (SFCL) has the attractive characteristics that can adjust the current limiting level by the turns ratio and the winding direction of two coils. To apply this type SFCL into power system, the analysis for the recovery characteristics of it together with the current limiting characteristic is needed. In this paper, the experiments of the current limiting and the recovery characteristics of the flux-lock type SFCL with YBCO thin film were performed. The recovery characteristics of the flux-lock type SFCL dependent on the winding direction of two coils were analyzed through the comparison with the resistive type SFCL.

• 대한전기학회논문지:전력기술부문A
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• 제55권2호
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• pp.62-66
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• 2006

We investigated the characteristics of the hybrid-type superconducting fault current limiter (SFCL) by the number of secondary windings. The SFCL consists of a transformer, which has a primary winding and several secondary windings with serially connected $YB_{a2}Cu_{3}O_{7}$ films. In order to increase the capacity. of the SFCL, the serial connection between each current limiting unit is necessary. Resistive-type SFCL has a difficulty in quenching simultaneously between the units due to slight differences of their critical current densities. The hybrid-type SFCL could achieve the simultaneous quenching through the electrical isolation and the mutual flux linkage among the units. We confirmed that the capacity of the SFCL could be increased effectively through the simultaneous quenching among the units. In addition, the power burden of the system could be reduced by adjusting the number of secondary windings. We will investigate the method to increase the capacity through serial and Parallel connections among current limiting units.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.971-972
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• 2011

초전도 저항형 한류기는 계통에서 발생하는 대규모의 사고 전류를 매우 빠른 시간 안에 효과적으로 제한할 수 있어 주목받고 있는 초전도 전력기기이다. 저항형 한류기를 제작할 때 사용되는 초전도 선재의 총 길이는 저항형 한류기의 전체 설계에 있어서 가장 핵심적인 변수중 하나로 기존의 허용전기장을 이용한 방법으로 도출될 수 있다. 하지만 기존의 방법에서는 계통의 라인 저항을 고려하지 않는 가정을 도입 했기 때문에 이를 이용하여 설계할 경우 실제로 시스템에서 요구하는 설계 변수와 큰 차이를 보일 수 있다. 본 논문에서는 라인저항의 영향을 고려한 허용 전기장을 도출하고, 새로 계산된 선재의 길이와 기존의 방법을 이용하여 계산된 선재의 길이를 비교해 봄으로써 보다 정확한 설계의 가능성을 제시한다.