• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.3
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• pp.323-327
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• 2008

We investigated the quench characteristics of a flux-lock type superconducting fault current limiter (SFCL) depending on the methods of the serial and parallel connections between the superconducting elements. The flux-lock type SFCL consists of two coils. The primary coil is wound in parallel to the secondary coil through an iron core, and the secondary coil is connected to the superconducting elements in series and parallel. In this paper, the analyses of voltage, current, and resistance of the superconducting elements connected in serial and parallel were performed to increase the power capacity of the flux-lock type SFCL. A part of the superconducting elements was not quenched in $2{\times}2$ serial connection between the elements and then the power burden of the quenched elements was increased. However the elements with $2{\times}2$ parallel connection was all quenched. This means that the power burden of each superconducting element can be reduced under the same conditions. We found that $2{\times}2$ parallel connection was more profitable for the current limiting effects and the increase of the power capacity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.155-156
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• 2005

We investigated the quench characteristics of the flux-lock type superconducting fault current limiter (SFCL) integrated three-phase according to fault types such as the single-line-to-ground fault, the double-line-to-ground fault and the three-line-to-ground. The structure of integrated three-phase flux-lock type SFCL consists of single core which have three-phase flux-lock reactors. The superconducting elements connected sound phase as well as fault phase happened to quenching. Therefore we conformed that the superconducting elements were dependent.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.157-158
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• 2005

Superconducting fault currents(SFCLs) are expected to improve not only reliability but also stability of real power systems. The analysis on the single line-to-ground fault of the integrated three phase flux-lock type SFCL, which consists of three flux-lock reactor wound on an iron core in each single phase and three YBCO thin films, was investigated in current limiting operation characteristics. We compared 21turn numbers with 42turn numbers according to wound turn numbers each the coil 2 under the additive polarity winding operation between coil 1 and coil 2. The three phase flux-lock type SFCL using an iron core differently operates general three phase resistive SFCLs. When a single line-to-ground fault occurred, the SFCL's three units were quenched after fault onset. We confirmed effective current limiting operation characteristics with adjustable inductance level.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05b
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• pp.20-23
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• 2003

The operational characteristics of flux-lock type high-Tc superconducting fault currentlimiters(HTSC-FCLs) was described and currents equation at each coil was derived from equivalent circuit. $YBa_{2}Cu_{3}O_{7-x}$(YBCO) thin film was used as the current limiting elements of the flux-lock type HTSC-FCL, which were fabricated by etching the YBCO thin film into 2 mm wide and 420 mm long meander line consisting of foureen stripes with different length. The 2nd peak on the current of coil 2 after a fault disappeared by current of the 3rd winding, which was installed in the flux-lock type HTSC-FCL.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.05a
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• pp.146-148
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• 2006

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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.39-40
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• 2007

The analysis of fault current limiting characteristics according to variation of fault current level in the integrated three-phase flux-lock type superconducting fault current limiter (SFCL), which consisted of three-phase flux-lock reactor wound on an iron core with the same turn's ratio between coil 1 and coil 2 for each single phase, was performed. To analyze the current limiting characteristics of this integrated three-phase flux-lock type SFCL, the short circuit experiments was carried out the various three-phase faults such as the single line-to-ground fault, the double line-to-ground fault, the triple line-to-ground fault. From the experimental results, the fault current limiting characteristic was improved according to increase of fault current level.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.08a
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• pp.105-108
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• 2002

In this paper, we investigated the fault current limiting characteristic of flux-lock type High-Tc superconducting fault current limiter(HTSC-FCL), which is comprised of a flux-lock reactor and an external magnetic field coil covering the HTSC element In this HTSC-FCL, the initial limiting current level can be controlled by adjusting the inductance of the each coil. Furthermore, the fault current limiting characteristics of HTSC-FCL can be improved by applying 'the external magnetic field into the HTSC element We performed the computer simulation by numerical analysis about the flux-lock type HTSC-FCL and compared the results of experiment with simulation ones. We can obtain the same results from both the computer simulation and the experiment except for the time immediately after fault occurs.

• Proceedings of the KIEE Conference
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• 2007.04b
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• pp.35-36
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• 2007

We investigated the characteristics of three phase flux-lock type SFCL. Three phase flux-lock type consists of three reactor wound on an iron core in each single phase and the secondary coil is connected to the superconducting elements in series. the superconducting elements with serial connection were quenched simultangously in the single line-to-ground fault.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.9
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• pp.812-815
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• 2007

To apply the superconducting fault current limiter(SFCL) into a power system, the analysis for its recovery characteristics as well as the consideration for its cooperation with other protecting machine such as a circuit breaker is required. The recovery characteristics of the flux-lock type SFCL like its current limiting characteristics are dependent on the winding direction of two coils. 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. From the analysis on the experimental results due to the winding direction of two coils, the limited fault current in case of the additive polarity winding was observed to be lower than that for the case of the subtractive polarity winding. In addition, the recovery time was found to be faster in case of the additive polarity winding compared to the subtractive polarity winding.

• Proceedings of the KIEE Conference
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• 2007.11b
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• pp.87-88
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• 2007

We investigated the current limiting characteristics of flux-lock type superconducting fault current limiter using YBCO films University, Gwangju health college. The flux-lock type SFCL consisted of the transformer with a primary winding and a secondary winding connected in parallel, and the superconducting element was connected with secondary winding in series or parallel. Serial and parallel connections of superconducting elements are necessary for the increase of voltage and current capacities when we intend to apply the flux-lock type SFCL.