• Progress in Superconductivity and Cryogenics
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• v.19 no.4
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• pp.40-44
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• 2017

This paper analyzed the fault current limiting characteristics of the previously proposed transformer superconducting fault current limiter (TSFCL) interruption system according to its transformer type. The TSFCL interruption system is an interruption technology that combines a TSFCL, which uses a transformer and a superconductor, and a mechanical DC circuit breaker. This technology first limits the fault current using the inductance of the transformer winding and the quench characteristics of the superconductor. The limited fault current is then interrupted by a mechanical DC circuit breaker. The magnitude of the limited fault current can be controlled by the quench resistance of the superconductor in the TSFCL and the turns ratio of the transformer. When the fault current is controlled using a superconductor, additional costs are incurred due to the cooling vessel and the length of the superconductor. When the fault current is controlled using step-up and step-down transformers, however, it is possible to control the fault current more economically than using the superconductor. The TSFCL interruption system was designed using PSCAD/EMTDC-based analysis software, and the fault current limiting characteristics according to the type of the transformer were analyzed. The turns ratios of the step-up and step-down transformers were set to 1:2 and 2:1. The results were compared with those of a transformer with a 1:1 turns ratio.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.8
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• pp.107-112
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• 2007

The flux-lock type SFCL consists of transformer with primary and secondary windings connected to a superconducting element in serial. It can be divided into the subtractive and the additive polarity windings according to the winding direction. It could change the fault current limiting characteristics according to the inductance ratio between the coil 1 and coil 2. We investigated the voltage-current characteristics of the flux-lock type SFCL according to the increment of applied voltage. When the applied voltage of the SFCL with the subtractive and the additive polarity windings was increased a initial limiting current ($I_{ini}$) and the quench time of the superconducting element were increased. The recovery time of the superconducting element was increased by increment of applied voltage. Therefore, it was confirmed that recovery characteristics in the flux-lock type SFCL were largely dependent on the consumed energy of a superconducting element because of increment of the consumption power into the superconducting element.

• 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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.189-189
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• 2010

The Improved flux-lock 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 through the spot at the beginning of the fault current in the Improved flux-lock type SFCL. The experiment results that the fault current limiting characteristics was difference according to the point of a fault current started. Through the analysis, it was shown that shorter the time of a phase transition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.235-236
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• 2007

변압기형 전류제한기는 1차측이 선로와 연결되어 있고 2차측은 고온 초전도 소자가 연결되어 있다. 사고 시 고온 초전도 소자의 부담을 줄이고자 2차측에 무유도 션트 저항을 연결하여 특성을 분석하였다. 션트가 없을 때 선로전류 제한율은 좋은나 2차측에 있는 초전도 소자가 부담해야하는 전력은 크다. 션트가 있을 때는 선로전류 제한율은 감소하는 반면 초전도 소자가 부당해야하는 전력은 크게 줄어들었다. 이때 2차측의 전압과 전류 중 전압의 감소 폭이 더 컸으며 션트저항 값이 작을수록 전압의 크기는 더 작아졌다. 결론적으로 션트저항의 연결에 따라 제한율은 낮아지지만 소자가 부담해야하는 전력은 크게 줄어든다.

• Proceedings of the KIEE Conference
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• 2008.07a
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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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.4
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• pp.595-599
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• 2018

Interruption system with the transformer type superconducting fault current limiter(TSFCL) is proposed in this paper. The interruption system with a TSFCL is a technology that it maximizes the interruption function of a mechanical DC circuit breaker using a transformer and a superconducting fault current limiter. By a TSFCL, the system limits the fault current till the breakable current range in the fault state. Therefore, the fault current could be cut off by a mechanical DC circuit breaker. The Interruption system with a TSFCL were designed using PSCAD/EMTDC. In addition, the Interruption system with a TSFCL was applied to the DC test circuit to analyze characteristics of a current-limiting and a interruption operation. The simulation results showed that the Interruption system with a TSFCL interrupted the fault current in a stable when a fault occurred. Also, The current-limiting rate of the Interruption system with a TSFCL was approximately 69.55%, and the interruption time was less than 8 ms.

• Proceedings of the KIEE Conference
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• 2011.07a
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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.

• Progress in Superconductivity and Cryogenics
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• v.7 no.4
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• pp.28-31
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• 2005

To verify the feasibility of bifilar winding type superconducting fault current limiter (SFCL) using BSCCO tape, two types of magnets were fabricated and tested by short-circuit in this research. Even if the FCL using high Tc superconducting (HTS) tape has zero resistance in normal state, it needs to be wound as a bifilar winding for zero inductance. Solenoid type and pancake type bifilar winding magnets are designed and fabricated with the same length of BSCCO tape. The test system consists of AC power supply, transformer, fault switch, load and bifilar winding magnet. The applied AC voltages during fault duration, 0.1s, were from 0.5V to 20V. The test results without bifilar winding magnet were compared with those with each type magnets. The test results include voltage against magnet, transport current and generated resistance curve. Thermal stability, the recovery time, was studied from the results of two type magnets. The pancake type was the most effective to limit fault current but the solenoid type was thermally the most stable. From this research, short-circuit characteristics of the two types were obtained.