• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.288-288
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• 2008

The flux-coupling type superconducting fault current limiter(SFCL) is composed of a series transformer and superconducting unit of the YBCO thin films. The primary and secondary coils in the transformer were wound in series each other through an iron core and the YBCO thin film was connected with secondary coil in parallel. In a normal condition, the flux generated from a primary coil is cancelled out by its structure and the zero resistance of the YBCO thin films. When a fault occurs, the resistance of the YBCO thin films was generated and the fault current was limited by the SFCL. In this paper, we investigated the fault current limiting characteristics according to fault current level in the flux-coupling type SFCL. The experiment results that the fault current limiting characteristics was improved according to increase of the fault current level.

• Transactions on Electrical and Electronic Materials
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• 제8권5호
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• pp.222-225
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• 2007

In this paper, we compared the current limiting characteristics of both the hybrid type and the flux-lock type superconducting fault current limiters(SFCLs), which have a magnetic coupling structure between a primary winding and several secondary windings. The limiting impedances of two SFCLs were derived from each equivalent circuit considering the design parameters of SFCL such as the self-inductance of secondary winding and the resistance of $high-T_C$ superconducting(HTSC) element. Through the comparison for the limiting impedances of two SFCLs considering the dependence of the HTSC element's resistance on the applying voltage into the SFCL, the hybrid type SFCL was confirmed to have larger limiting impedance with smaller resistance of HTSC element than the flux-lock type SFCL. It was expected from the analysis that the hybrid type SFCL was more advantageous than the flux-lock type SFCL from the viewpoint of the fault current limiting level.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.344-345
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• 2009

The flux-coupling type superconducting fault current limiter(SFCL) is composed of a series transformer and superconducting unit of the YBCO coated conductor. The primary and secondary coils in the transformer were wound in series each other through an iron core and the YBCO coated conductor was connected with secondary coil in parallel. In a normal condition, the flux generated from a primary coil is cancelled out by its structure and the zero resistance of the YBCO thin films. When a fault occurs, the resistance of the YBCO coated conductor was generated and the fault current was limited by the SFCL. In this paper, we investigated the fault current limiting characteristics according to turn ratio in the flux-coupling type SFCL. The experiment results that the fault current limiting characteristics was improved according to turn ratio.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 추계학술대회 논문집
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• pp.249-251
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• 2008

We investigated a flux-coupling type superconducting fault current(SFCL) limiter. The SFCL consisted of the primary and secondary coils, which were wound in series each other through an iron core. Superconducting unit was connected with secondary coil in parallel. The flux generated from a coil in normal operation is cancelled out by its structure and the zero resistance of the superconducting unit. In this paper. In order to compare the current limiting effects of the SFCL by applied voltage. When a lied voltage was increased, quench time was shortened Fast quench time is important component under the same fault condition because power burden of the SFCL is reduced by that of the superconducting units. The current limiting behavior of flux-coupling type SFCL was dependent upon the applied voltage.

• 한국전기전자재료학회논문지
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• 제22권8호
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• pp.694-697
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• 2009

The separated three-phase flux-coupling type superconducting fault current limiter(SFCL) is composed of a series transformer and superconducting unit of the YBCO coated conductor. The primary and secondary coils in the transformer were wound in series each other through an iron core and the YBCO coated conductor was connected with secondary coil in parallel. In this paper, we investigated the current limiting characteristics through winding number of coil 2 and winding direction in the flux-coupling type SFCL. Through the analysis, it was shown that additive polarity condition and lower winding number of coil 2 have advantaged from the point of view of fault current limiting and burned of YBCO coated conductor.

• 전기학회논문지
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• 제60권5호
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• pp.1073-1077
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• 2011

The breaking capacity of circuit breakers could be no more increased in the electric power system. This is because the fault current increases due to continuous increases in electric power demand and facilities. To solve the problem, it is necessary to come up with an alternative. The superconducting fault current limiter (SFCL) has received an attention among various alternatives. The SFCL effectively reduce a fault current in cooperation with a power circuit breaker. A various types of the SFCL are suggested and a study on them have been progressed. As a result of it, the SFCL can be applyed to the electric power system in the near future. But, a study on recovery behaviors of the SFCL is not enough for applying to the electric power system. If the superconducting elements do not completely recover to the superconducting state after fault operation, it might be a breakdown of the superconducting elements due to heavy power burden and it gives an bad influence on the working of other electric devices. Additionally, the distribution power system has reclosing operation such as open-0.3sec-closed/open-3min-closed/open procedure. So we need to study more about improvement of the recovery behaviors of the SFCL. In this paper, we analyzed the recovery behaviors of a flux-coupling type SFCL according to reclosing operation when a single line-to-ground fault occurred and we compared recovery behaviors of the SFCL with and without a neutral line between secondary reactors and superconducting elements. Also, the flux-coupling type SFCL has advantageous for increases of capacity by controlling the variation in turn ratios between two reactors. Consequently, when the number of turns of the secondary reactors increased, the power burden of the superconducting elements was bigger due to the increase of impedances of the secondary reactors. To distribute the power burden, two superconducting elements connected in series and the balanced quenching of the superconducting elements was induced by connecting a neutral line.

• Transactions on Electrical and Electronic Materials
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• 제6권5호
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• pp.193-197
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• 2005

We investigated fault current limiting characteristics of the flux-lock type superconducting fault current limiter (SFCL), which consisted of a primary winding and several secondary windings connected in series between $high-T_C$ superconducting (HTSC) thin films. Each YBCO thin film has a 2 mm wide and 42 cm long meander line with 14 stripes of different length. The power imbalance due to the slight difference of Ie between YBCO current limiting elements causes the significant power burden on YBCO element with lower $I_C$. We confirmed from our experiments that the mutual coupling between the primary winding and secondary windings of the flux-lock type SFCL reduced the power imbalance between YBCO current limiting elements compared with the resistive type SFCL connected in series.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.292-292
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• 2008

The superconducting fault current limiter(SFCL) can be used to limit fault current level in electrical transmission line and power system. Up to now, there are several kinds of SFCL that have proposed and it is expects that they will be applied to appropriated position considering their own properties; initial fault current limiting instant and the current limiting characteristics. In this paper, we investigated the initial fault current limiting instant and the amplitude of initial fault current in the resistive type, the flux-lock type, the flux-coupling type and the transformer type SFCL. Experiment results show that the initial fault current limiting instant and the amplitude of initial fault current of the SFCLs are dependant on the ratio of inductance of primary and secondary coils.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.2146_2147
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• 2009

현재 많은 초전도 한류기들이 개발되었고 현재도 실계통 적용을 위해 개발중이다. 본 논문에서는 초전도 소자만을 이용한 저항형 초전도 한류기와 변압기와 초전도 소자를 접목한 자속결합형 초전도 한류기의 사고전류 제한 특성과 초전도 소자의 퀜치특성을 비교 분석하였다. 자속결합형 초전도 한류기는 변압기 코일의 턴수를 조절함으로써 사고전류의 크기 및 퀜치 특성을 개선시키는 반면 저항형 초전도 한류기는 초전도 소자의 불균일 퀜치와 사고전류의 크기를 조절하기 힘들다는 단점을 가지고 있다. 또한 자속결합형 초전도 한류기의 경우에서 초전도 소자에 발생하는 전압의 크기가 현저히 작음을 알 수 있었다. 초전도 소자의 전압이 높고, 퀜치 불균일로 인해서 일부 전력 부담이 편중되는 소자의 열화가 더 빨리 진행될 것이다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.2166-2167
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• 2011

급격히 증가해온 사고전류로부터 전력망을 보호하기 위한 해결책으로 초전도 한류기가 제시되어 왔다. 초전도체의 영저항 특성을 이용한 초전도 한류기는 정상상태시 무손실로써 동작하기 때문에 전력 공급의 효율성을 저하시키지 않는 장점이 있다. 이러한 초전도 한류기를 전력망에 적용하기 위해서는, 용량증대의 문제가 우선적으로 해결되어야 하는 바, 초전도 소자의 직 병렬 연결과 더불어 변압기를 이용한 여러 타입의 초전도 한류기가 제시 및 연구되어 왔다. 본 논문에서는 변압기형 초전도 한류기와 자속결합형 초전도 한류기를 구성하여 단락사고 발생시 각 초전도 한류기의 회복성능을 비교 분석 하였다. 각 초전도 한류기는 사고전류 제한 동작특성에 따라 회복시간의 차이를 보였다.