• 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 KIEE Conference
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• 2011.07a
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• pp.718-719
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• 2011

Lately, the demand for electrical power has been significantly increased. As a result a power transmission system has been improved. On the other hand fault current increased more than past. Superconducting fault current limiter (SFCL) is one of the solutions to limit fault current. However, SFCL's research has not advanced in a power transmission system fully. Therefore, we studied effect of SFCL in a power transmission system. The power distribution system is open-loop circuit, but a power transmission system is closed-loop system. Consequently, Fault current in a power transmission system is larger than fault current in a power distribution system. we exerimented a simple closed-loop power transmission system circuit.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.135_136
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• 2009

This paper proposes the new reclosing scheme considering the recovery time of SFCL in distribution systems which is based on variable dead time control. The main idea is that it uses the carrier signal to distinguish whether the fault is instantaneous or permanent following initial recloser opening. The system and SFCL is modeled by using Electromagnetic Transient Program(EMTP) and the validity of the reclosing scheme represented in this paper is analyzed according to the value of the fault resistance and the time of the fault removal.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.266_267
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• 2009

22.9kV HTS(High Temperature Superconducting) cable and SFCL(Superconducting Fault Current Limiter) will be installed to Icheon 154kV substation for real distribution power system operation in 2010. This paper proposes CLR (Current Limiting Resistance) specification of the SFCL and fault current condition fo the HTS cable for applying to Korean power system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.3
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• pp.450-454
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• 2009

This paper analyzes a asymmetry current with SFCL (Superconducting Fault Current Limiter) operation during transient period, when a fault occurs in power systems. The principle of asymmetry current nature is reviewed and asymmetry components reduction with SFCL operation is explained. To verify the performance of SFCL, a EMTP/ATPDraw model of SFCLs using MODELS language developed and simulated. Throughout the simulation, results presents the main factors for reducing the asymmetry component of fault current are not a quenching time, but a limiting resistance of SFCL and fault initiated angle.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.12
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• pp.74-79
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• 2012

Currently, separated buses were increased to limit a fault currents in power transmission system. However, separated buses caused bad influences such as a decrease of reliability and stability. Superconducting fault current limiter (SFCL) was proposed to limit a fault current lately and that has many merits beside any other solutions. Therefore, we proposed the install of Superconducting fault current limiter (SFCL) in power transmission system with separated bus. And our proposal was verified by reliability of power system.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.229-230
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• 2007

We investigated the quench characteristics of a superconducting element, two superconducting elements in order to increase the current capacity of flux lock type SFCL. 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. The applied voltage at that time was 160 ${\sqrt{3}}$. We found that the parallel connection between the superconducting elements increased the power capacity and let quench characteristics improve through their mutual linkage.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.1
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• pp.38-42
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• 2004

In this paper we analyzed the electromagnetic behavior of a superconducting fault current limiter (SFCL) under the quench state using FEM. The analysis model used in this work is 5.5 KVA meander-line type SFCLs which are currently developed by Superconductor Power System Lab in Korea Electric Power Research Institute. Meshes of 3,650 triangular elements were used in the analysis of this SFCL. Analysis results showed that the distribution of current density was concentrated to inner curved line in meander-line type SFCL and the maximum current density was 14.61 A/$m^2$ and also the maximum Joule heat was 2,030 W/$m^2$ in this region. We think that the new and the modified structure must be considered for an uniform distribution of the electromagnetic field.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.717-719
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• 2001

This paper deals with simulation of the three-phase dc reactor type fault current limiter(FCL). This is a preliminary step to develop the FCL's faculties for an application to high voltage transmission line. A three-phase dc reactor type FCL consists of transformers, diodes, and a superconducting coil. By this simulation for the short-circuit test we can investigate the safety of FCL's elements. And, result of simulation will contribute parameter toward optimal design.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.916-917
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• 2001

We investigated the properties of a hybrid type superconducting fault current limiter (SFCL), which consists of a transformer with multiple secondary windings and resistive $YBa_2Cu_3O_7$ (YBCO) thin film stripes. The secondary windings of the transformer were coupled with each other, and a superconducting current limiting unit of YBCO stripes was connected to each of them as a switch. Simple connection in series of SFCL units tends to produce imbalance in power among the units due to slight differences in quench current. In current design, magnetic coupling between the SFCL units provides a solution to power dissipation imbalance, inducing simultaneous quench by current redistribution in the YBCO films.