• 한국초전도ㆍ저온공학회논문지
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• 제3권1호
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• pp.40-44
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• 2001

Recently. the high-tc superconducting fault col-rent limiters (SFCL) are studied worldwide to be classified as a resistive type or an inductive type such as a magnetic shielding type and a inductive type. The high-tc SFCL wish an open core belongs to the magnetic shielding type SFCL. Unlike conventional magnetic shielding type SFCLS it uses the open core to reduce the mechanical vibrations and installation space, The high-tc SFCL with an open core was designed and manufactured by stacking three BSCCO 2212 tubes. It was tested in the maximum source voltage of 400 Vrms. The results such as the reduction of fault current and impedance of the SFCL are described in this paper. The results show that the fault current in the source voltage of 400 Vrms was reduced to be about 123 Apeak. about 3.9 times greater than the normal state current. Also, the impedance of the high-tc SFCL was about 9${\Omega}$ about 9 times greater than the normal state impedance. The impedance of the SFCL appears just after the fault, and its size is dependent on the source voltage. From the impedance, the inductance of the SFCL was calculated.

• 대한전기학회논문지:전력기술부문A
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• 제55권6호
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• pp.255-258
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• 2006

We investigated the operating characteristics of the hybrid-type superconducting fault current limiter (SFCL) according to the inductance of secondary windings. The hybrid type SFCL consists of a transformer that has a primary winding and a secondary winding with serially connected $YBa_2Cu_3O_7$ (YBCO) films. The resistive-type SFCL has difficulty when it comes to raising the capacity of the SFCL due to slight differences of critical current densities between units and structure of the SFCL. The hybrid-type SFCL with closed-loop is able to achieve capacity increase through the electrical isolation and reduction of the inductance of the secondary winding with a superconducting element of the same critical current. On the other hand, the current limiting characteristics were nearly identical in the hybrid-type SFCL with open-loop compared to closed-loop, but quench time was longer than the hybrid-type SFCL with closed-loop. We confirmed that the capacity of the SFCL was increased effectively by the reduced inductance of the secondary winding. In addition, the power burden of the system also could be lowered by reducing the inductance of secondary winding.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 초전도 자성체 연구회
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• pp.77-79
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• 2003

The quench characteristics of flux-lock type high-Tc superconducting fault current limiters(SFCL) was investigated. $YBa_2Cu_3O_{7-x}$(YBCO) thin film was used as the current limiting elements of the flux-lock type SFCL. The quench characteristics of current limiting elements consisting of the flux-lock type SFCL was more improved than that of the resistive type SFCL.

• 전기학회논문지
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• 제58권5호
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• pp.905-910
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• 2009

For proper application and operation of a SFCL(Superconducting Fault Current Limiter) in distribution systems, the prior investigation of fundamental characteristics and its effects analysis to the systems are very important. A point of view in coordination with recloser in distribution systems, characteristic about quenching and recovering of SFCL should be studied. Especially, its detailed study of recovery characteristic is particularly important to avoid conflict between the SFCL and the recloser. In this paper, the resistive type SFCL and recloser, which used in distribution system, were implemented using EMTP/ATPDraw and MODELS language. To analyze the recovery characteristics of SFCL according to recloser operation in distribution systems, case studies have been simulated and investigated.

• 전기학회논문지
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• 제60권6호
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• pp.1268-1273
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• 2011

The study on power capacity increase of superconducting fault current limiter (SFCL) is one of the most important researches to apply a SFCL in the power system. To achieve this, we thought that the unbalanced quenching problem generated in series connection of superconducting units should be solved. In this paper, we investigated the quenching characteristics of superconducting units in the transformer-type SFCL with or without the neutral line between secondary windings and superconducting units. In case of transformer-type SFCL without neutral line, the connection structure of superconducting units is identical to that of the resistive-type SFCL connected in series. Therefore, the unbalanced quenching was occurred by difference of critical current between superconducting units. However, in case of transformer-type SFCL with neutral line, the superconducting units with different critical current were simultaneously quenched. It was because the currents induced by secondary winding were separately flowed through the superconducting units. By these results, we confirmed that the resistances and consumption powers of the superconducting units were equally generated.

• 전기학회논문지
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• 제62권7호
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• pp.925-930
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• 2013

The fault current of the power transmission system is greater than that of the power distribution system. Therefore, the introduction of superconducting fault current limiter (SFCL) is more needed to reduce the increased fault current. The trigger-type SFCL consists of the high-temperature superconducting element (HTSC), the current limiting reactor (CLR) and the circuit breaker (CB). The trigger-type SFCL can be used to supplement the disadvantages of the resistive-type SFCL. The operation characteristics of the current ratio differential relay which is usually applied to the protection device of the power transmission system are expected to be affected under fault conditions and the applicability of the trigger-type SFCL. In this paper, we analyzed the operating characteristics, by the fault conditions, between the current ratio differential relay for line protection and the trigger-type SFCL in the power transmission system through the PSCAD/EMTDC simulation.

• 한국전기전자재료학회논문지
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• 제24권5호
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• pp.410-415
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• 2011

In this paper, we investigated the fault current limiting and the load voltage sag suppressing characteristics of the flux-lock type SFCL, designed with the additive polarity winding, according to the variations of turn number's ratio and the comparative analysis between the resistive type and the flux-lock type SFCLs were performed as well. From the analysis for the short-circuit tests, the flux-lock type SFCL designed with the larger turn number's ratio was shown to perform more effective fault current limiting and load voltage sag suppressing operations compared to the flux-lock type SFCL designed with the lower turn number's ratio through the fast quench occurrence of the high-$T_C$ superconducting (HTSC) element comprising the flux-lock type SFCL. In addition, the recovery time of the flux-lock type SFCL after the fault removed could be confirmed to be shorter in case of the flux-lock type SFCL designed with the lower turn number ratio.

• 한국초전도ㆍ저온공학회논문지
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• 제6권3호
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• pp.50-55
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• 2004

We fabricated and tested a resistive type superconducting fault current limiter (SFCL) of three-phase 6.6 $kV_{rms}/200 A_{rms}$ rating based on YBCO thin films grown on sapphire substrates with a diameter of 4 inches, Short circuit tests were carried out at a accredited test facility for single line-to- ground faults, phase-to-phase faults and three-phase faults, Each phase of the SFCL was composed of 8${\times}$6 elements connected in series and parallel respectively. Each element was designed to have the rated voltage of 600 $V_{rms}$. A NiCr shunt resistor of 23 Ω was connected to each element for simultaneous quenches. Firstly, single phase-to-ground fault tests were carried out. The SFCL successfully developed the impedance in the circuit within 0.12 msec after fault and controlled the fault current of 10 $kA_{rms} below 816 A_{peak}$ at the first half cycle. In addition, in case of phase-to-phase fault and three- phase fault test. simultaneous quenches among the SFCLs of the phases successfully accomplished. In conclusion. the SFCL showed excellent performance of current limitation upon fault and stable operation regardless of the amplitude of fault currents.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2000년도 KIASC Conference 2000 / 2000년도 학술대회 논문집
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• pp.91-94
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• 2000

We fabricated resistive super- conducting fault current limiters (SFCL) based on YBCO thin films grown on 2" diameter $Al_{2}O_{3}$ substrates. Two SFCLs with nearly identical properties. two SFCLs with nearly identical properties were connected in series to investigate simultaneous quenching. There was a difference of several half cycles in their quench starting time, although the difference was not more than 0.1 msec when they were operated separately. This imbalance was removed by connecting a shunt resistor to an SFCL in parallel. Increased power input at high voltages also reduced the initial imbalance in power dissipation. Further efforts on the simultaneous quench in SFCLs connected in series are on the way through methods such as the artificial control of quench speed.peed.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 추계학술대회 논문집
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• pp.332-334
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• 2003

A subcooled liquid nitrogen cryostat is required for the cooling of a 6.6 ㎸, 200 A resistive type superconductive fault current limiter (SFCL). To help understand and design an appropriate cryostat for SFCL a prototype cryostat was fabricated and tested. Several states of subcooled liquid nitrogen were obtained by using cryocooler and helium gas. The temperature was uniformly distributed inside the liquid nitrogen vessel within the range of 0.4 K proving the effectiveness of the conduction cylinder.