• Progress in Superconductivity
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• v.3 no.2
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• pp.229-234
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• 2002

In this paper, we analyzed the fault current performance in a $high-T_{c}$ superconductor(HTS) which was installed on flux-lock reactor with an external magnetic field coil covering the HTS. In this HTS fault current limiter using flux-lock concepts, the initial limiting current level can be controlled by adjusting the inductance of the coils. Furthermore, the current limiting characteristics of $high-T_{c}$ superconducting FCL can be improved by applying the external magnetic field into the $high-T_{c}$ superconductor. This paper discusses current limiting performance according to the inductance of the coil 1 in two cases with ac magnetic field coil or not and suggests the methods to improve the current limiting factor $P_{limit}$, which is defined as the ratio of the limited current $I_{FCL}$ at the current limiting phase to the prospective short -circuit current $I_{PSC}$.TEX> PSC/.

• 한국초전도학회:학술대회논문집
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• v.11
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• pp.70-70
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• 2001

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.3
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• pp.398-402
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• 2008

Recently, the development of superconducting fault current limiters (SFCLs) has been required as power demands increase in the power system. A distribution-level prototype resistive SFCL using coated conductor (CC) has been developed by Hyundai Heavy Industries Co., Ltd. and Yonsei University for the first time in the world. The ratings of the SFCL are 13.2kV/630A at normal operating condition. A novel non-inductive winding method is used in fabricating coils so there is almost zero impedance during normal operation. The distribution SFCL is cooled by sub-cooled liquid nitrogen $(LN_2)$ of 65K and 3 bar to enhance cryo-dielectric performance, critical current density, and thermal conductivity. In order to make reliable operation of an SFCL in real power systems, we monitored and controled its operation conditions by using supervisory control and data acquisition (SCADA) method. Thus, a monitoring system for the SFCL employing information technology (IT) is proposed and developed to be on the lookout for the operation conditions such as inside temperature, inside pressure, $LN_2$ level, voltage and current. Since operation temperature should be kept constant, bang-bang control for temperature feedback with a heater attached to the cold head of cryo-cooler is applied to the system. Short-circuit tests with prospective fault current of 10kA and AC dielectric withstand voltage tests up to 143kV for 1 minute were successfully performed at Korea Electrotechnology Research Institute. This paper deals with the development of a distribution level SFCL and its monitoring system for reliable operation.

• Journal of Electrical Engineering and Technology
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• v.6 no.4
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• pp.474-483
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• 2011

Solid-state fault current limiters (SSFCL) in power systems are alternative devices to limit prospective short circuit currents from reaching lower levels. Fault current limiters (FCL) can be classified into two categories: R-type (resistive) FCLs and L-type (inductive) FCLs. L-type FCL uses an inductor to limit fault level and is more efficient in suppressing voltage drop during a fault. In contrast, R-type FCL is constructed with a resistance and is more effective in consuming the acceleration energy of generators during a fault. Both functions enhance the transient stability of the power system. In the present paper, a novel SSFCL is proposed to enhance power system transient stability and power quality. The proposed SSFCL uses both functions of an L-type and R-type FCL. SSFCL consists of four diodes, one self-turn-off IGCT, a current-limiting by-pass inductor (L), and a variable resistance parallel with an inductor for improvement of power system stability and prevention of over-voltage across SSFCL. The main advantages of the proposed SSFCL are the simplicity of its structure and control, low steady-state impedance, fast response, and the existence of R-type and Ltype impedances during the fault, all of which improve power system stability and power quality. Simulations are accomplished in PSCAD/EMTDC.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.943-944
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• 2007

In this paper, the development and the test of 13.2kV/630A high-Tc superconducting fault current limiting coil are described. The fault current limiting coil made of Coated Conductor (CC) was fabricated with bifilar winding method for non-inductive characteristics and tested in the distribution power system level in Dec. 2006. In order to determine the length of the superconducting coil, applied voltage per unit length(V/m) was studied analytically and it was verified through experiments. For the volume minimization, the coil was designed with concentrical arrangement method. The short-circuit test was performed with the prospective fault current of asymmetrical 10kA whose maximum fault current was $30kA_{peak}$. In the test, the voltage drop and the current of the coil were measured and the resistance of the coil was obtained. Also, the temperature rise of the coil was calculated with the relationship between the resistance and the temperature of CC. In this paper, the experimental results are analyzed and compared with the simulation.