• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.960-962
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• 2005

In this paper, we investigated the quench characteristics of high-Tc superconducting(HTSC) elements in the integrated three-phase flux-lock type superconducting fault current limiter(SFCL) according to fault types such as the single-line-to-ground fault, the double-line-to-ground fault, the line-to-line fault and the triple-line-to-ground fault. The integrated three-phase flux-lock type SFCL is an upgrade version of single-phase flux-lock type SFCL. The structure of the integrated three-phase flux-lock type SFCL consisted of a three-phase flux-lock reactor wound on an iron core with the ratio of the same turn between coil 1 and coil 2 in each phase. When the SFCL is under the normal condition, the flux generated in the iron core is zero because the flux generated between two coils of each single phase is canceled out. Therefore, the SFCL's impedance is zero, and the SFCL has negligible influence on the power system. However, if a fault occurs in any single one of three phases, the flux generated in the iron core is not zero any more. The flux makes HTSC elements of all phases to quench irrespective of the fault type, which reduces the current in fault phase as well as the current of sound phase. It was obtained that the fault current limiting characteristics of the suggested SFCL were dependent on the quench characteristics of HTSC elements in all three phases.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.1
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• pp.68-72
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• 2013

The series connection-type superconducting fault current limiter (SFCL) with two magnetically coupled circuits was suggested and its effectiveness through the analysis on the current limiting and recovery characteristics was described. The fault current limiting characteristics of the proposed SFCL as well as the load voltage sag compensating characteristics according to the winding direction were investigated. To confirm the fault current limiting and the voltage sag suppressing characteristics of the this SFCL, the short-circuit tests for the simulated power system with the series connection-type SFCL were carried out. The series connection-type SFCL designed with the additive polarity winding was shown to perform more effective fault current limiting and load voltage sag compensating operations through the fast quench occurrence right after the fault appears and the fast recovery operation after the fault removes than that with the subtractive polarity winding.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.5
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• pp.410-415
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• 2011

In this paper, we investigated the fault current limiting and the load voltage sag suppressing characteristics of the flux-lock type SFCL, designed with the additive polarity winding, according to the variations of turn number's ratio and the comparative analysis between the resistive type and the flux-lock type SFCLs were performed as well. From the analysis for the short-circuit tests, the flux-lock type SFCL designed with the larger turn number's ratio was shown to perform more effective fault current limiting and load voltage sag suppressing operations compared to the flux-lock type SFCL designed with the lower turn number's ratio through the fast quench occurrence of the high-$T_C$ superconducting (HTSC) element comprising the flux-lock type SFCL. In addition, the recovery time of the flux-lock type SFCL after the fault removed could be confirmed to be shorter in case of the flux-lock type SFCL designed with the lower turn number ratio.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.6
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• pp.940-945
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• 2016

In this paper, zero sequence equivalent circuit of Yg-Yg three phase core-type transformer is analyzed. Many problems by iron core structure of the three phase transformer due to asymmetric three phase lines, which includes line disconnection, ground fault, COS OFF, and unbalanced load are reported in the distribution system. To verify a feasibility of zero sequence impedance of Yg-Yg type three phase transformer, fault current generation in the three phase core and shell-type Yg-Yg transformer is compared by PSCAD/EMTDC when single line ground fault is occurred. As a result, shell-type transformer does not affect the flow of fault current, but core-type transformer generate an adverse effect by the zero sequence impedance. The adverse effect is explained by the zero sequence equivalent circuit of core-type transformer and Yg-Yg type three phase core-type transformer supplies a zero sequence fault current to the distribution system.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.2
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• pp.361-370
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• 2024

In this paper, a method was studied for applying a series resonant type fault current limiter that can be manufactured at low cost to the smart grid distribution system. First, the impact of the harmonic components of the short-circuit fault current injected into the series resonance circuit of the fault current limiter on the peak value of the transient response was analyzed, and a methodology for determining the steady-state response was studied using percent impedance-based fault current computation method. Next, the effectiveness of the method was verified by applying it to a test distribution line. The test distribution system using the designed current limiter was modeled using EMTP_RV, and a three-phase short-circuit fault was simulated. In the fault simulation results, it was confirmed that the steady-state response of the fault current accurately followed the design target value after applying the fault current limiter. In addition, by comparing the fault current waveform before and after applying the fault current limiter, it was confirmed that the fault current was greatly suppressed, confirming the effect of applying the series resonance type current limiter to the distribution system.

• Journal of Electrical Engineering and Technology
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• v.3 no.2
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• pp.213-217
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• 2008

The flux-lock type superconducting fault current limiter(SFCL) can apply the magnetic field into the high-$T_C$ superconducting(HTSC) element by adopting the magnetic field coil in its third winding. To apply the magnetic field into the HTSC element effectively, the capacitor for LC resonance is connected in series with the magnetic field coil. However, the current waveform of third winding for the application of the magnetic field is affected by the LC resonance condition for the frequency of the source voltage and can affect the waveform of the limited fault current. In this paper, the current waveform of the third winding in the flux-lock type SFCL according to LC resonance condition during a fault period was analyzed. From the differential equation for its electrical circuit, the current equation of the third winding was derived and described with the natural frequency and the damping ratio as design parameters. Through the analysis according to the design parameters of the third winding, the waveform of the limited fault current was confirmed to be influenced by the current waveform of the third winding and the design condition for the stable fault current limiting operation of this SFCL was obtained.

• 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 Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.511-514
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• 2002

In this paper, we compared the characteristic of fault current liminting in the magnetic shielding type High-Tc superconducting fault current limiter(FCL) using both Piecewise linear magnetization curve and real magnetization one of iron core. From this paper, the characteristics of fault current limiting in both cases showed many differences. The latter has higher fault current than the former, because the saturation of iron core was reflected and more accumulated during fault. It is expected that the more exact characteristic of magnetic shielding type High-Tc superconducting FCL was obtained in the case of design and modeling.

• Proceedings of the KIEE Conference
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• summer
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• pp.409-411
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• 2004

The need for Fault Current Limiters (FCL) is associated with the continuous growth and interconnection of modem power systems and increase in dispersed generation facilities, which result in progressive increase in the short circuit capacity far beyond their original design capacity. Fault Current Limiters (FCL) clips the fault currents and reduces the electromechanical stresses on the network and the need to handle excessive fault currents. In addition, the reduction of the fault duration Provided by the limiter should increase the power transmission capability and improve the dynamic stability. This paper proposes the model of resistive type superconducting fault current limiter using EMTDC(Electromagnetic transients for DC analysis program). In order to verify the effectiveness of the SFCL, in this paper, the analysis of fault current in a transmission system through the EMTDC based simulation by using the modeled component of a resistive type SFCL is peformed and the detailed results are given.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.355-356
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• 2009

In this paper, we investigated the fault current limiting characteristics according to the increase of voltage in the separates three-phase flux-lock type high-Tc superconducting fault current limiter using YBCO CC. The separated three-phase flux-lock type SFCL consists of single-phase flux-phase type SFCL in each phase. Superconductor was using the YBCO CC. To analyze the current limiting characteristics of a three-phase flux-lock type SFCL, the short circuit experiments were carded out fault such as the triple line-to-ground fault. The experimental result shows that fault current limiting characteristics was improved on the high voltage level.