• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.533-539
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• 2018

In this paper, the transformer type superconducting fault current limiter (SFCL) with additionally coupled circuit was suggested and its peak fault current limiting characteristics due to the fault condition to affect the fault current were analyzed through the fault current limiting tests. The suggested transformer type SFCL is basically identical to the previous transformer type SFCL except for the additional coupled circuit. The additional coupled circuit, which consists of the magnetically coupled winding to the primary and the secondary windings together with another superconducting element and is connected in parallel with the secondary winding of the transformer type SFCL, is contributed to the peak fault current limiting operation for the larger transient fault current directly after the fault occurrence. To confirm the fault current limiting operation of the suggested SFCL, the fault current limiting tests of the suggested SFCL were performed and its effective peak fault current limiting characteristics were analyzed through the analysis on the electrical equivalent circuit.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.9
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• pp.584-589
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• 2000

We fabricated resistive superconducting fault current limiters (SFCL) based on YBCO thin films grown on a 2-inch diameter Al2O3 substrate. The current limiting element was 1 mm wide and 260mm long meander line prepared by standard photolithography. The minimum quench current of the current limiting element was about 8 Apeak. This SFCL sucessfully controlled the fault current below 14.3 Apeak at the voltage of 100 Apeak which is otherwise to increase up to 141 Apeak. The quench completion time was less than 3 msec. The temperature of the current limiting element rose to about 200 K in 3 cycles after fault. The SFCL showed reproducible quench during hundreds times of repeated experiments.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.6
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• pp.614-619
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• 2023

The fault current limiting characteristics of three-phase transformer type superconducting fault current limiter (SFCL), which consisted of three-phase primary and secondary windings wound on E-I iron core, one high-TC superconducting (HTSC) element connected with the secondary winding of one phase and another HTSC element connected in parallel with other two secondary windings of two phases, were analyzed. Unlike other three-phase transformer type SFCLs with three HTSC elements, three-phase transformer type SFCL using double quench has the merit to perform fault current limiting operation for three-phase ground faults with two HTSC elements. To verify its proper three-phase ground fault current limiting operation, three-phase ground faults such as single-line ground, double-line ground and triple-line ground faults were generated in three-phase simulated power system installed with three-phase transformer type SFCL using double quench. From analysis of its fault current limiting characteristics based on tested results, three-phase transformer type SFCL using double quench was shown to be effectively operated for all three-phase ground faults.

• Progress in Superconductivity and Cryogenics
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• v.10 no.1
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• pp.42-47
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• 2008

In this paper, the fault current limiting characteristics for the superconducting fault current limiter(SFCL) using magnetic coupling between two coils were investigated. The SFCL consists of a high-$T_c$ superconducting(HTSC) element and two coils. This SFCL has different characteristics that depend on the connection form, the winding direction and the inductance ratio of two coils. The impedance and the operational current of the SFCL can be adjusted higher or lower than the resistance and the critical current of HTSC element. Therefore, the SFCL can change the amplitude of the limited fault current. To confirm it, the HTSC element was modeled and the fault current limiting characteristics of the SFCL were analysed through computer simulation. It was obtained from the analysis that the connection form and the winding direction of two coils of the SFCL were the important design parameters.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.1
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• pp.47-51
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• 2011

The superconducting fault current limiter (SFCL) with a peak current limiting function according to the initial fault current with the different amplitudes was suggested. The proposed SFCL, which consists of two limiting components, causes only the first superconducting element among two limiting components to be quenched in case that the initial fault current with the lower peak amplitude happens. On the other hand, the initial fault current with the higher peak amplitude makes both the superconducting elements of two limiting components to be quenched, which contributes to the peak current limiting function of the SFCL. To confirm the fault current limiting operation of the proposed SFCL, the short-circuit tests of the SFCL according to the fault angle were carried out and its effective fault current limiting operations could be discussed.

• 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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.2
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• pp.136-140
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• 2011

The fault current limiting characteristics of the flux-lock type superconducting fault current limiter (SFCL) using a transformer winding were investigated. The suggested flux-lock type SFCL consists of two parallel connected coils on an iron core and the transformer winding connected in series with one of two coils. In this SFCL, the high-TC superconducting (HTSC) element was connected with the secondary side of the transformer. The short-circuit experimental devices to analyze the fault current limiting characteristics of the flux-lock type SFCL using the transformer winding were constructed. Through the short-circuit tests, the flux-lock type SFCL using transformer winding was shown to perform more effective fault current limiting operation compared to the previous flux-lock type SFCL without the transformer winding from the viewpoint of the quench occurrence and the recovery time of the HTSC element.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.10
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• pp.889-894
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• 2007

We investigated the quench velocity of superconducting fault current limiter (SFCL) dependent on the source voltage. $YBa_2Cu_3O_7$ (YBCO) thin film was used as the current limiting element for SFCL. The analysis on the quench velocity of SFCL is essential to determine the capacity of circuit breaker (CB) or coordinate with CB. Generally, the quench velocity of SFCL is related with the short-circuit current. To change the short-circuit current, in this paper, the amplitude of the power source voltage is adjusted. Through the fault current limiting experiments, the quench velocity of SFCL was confirmed to increase fast as the source voltage increased. On the other hand, the peak limited current was shown to increase with steady rate of increase.

• Progress in Superconductivity and Cryogenics
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• v.4 no.1
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• pp.84-88
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• 2002

The resistive fault current limiter (SFCL) is a very attractive device for power networks. But it has a serious Problem in using YBCO films for fault current limiter is inhomogeneities caused by imperpect manufacturing. So simultaneous quenches are a difficult problem which elements for current limiting are connected in series for increasing voltage ratings. We investigated extended electric field-current characteristics for current limiting element of YBCO film when O-130mT magnetic field is applied. And quench characteristics were investigated in over all element and between elements of YBCO films. From the experiments, it was shown that applied magnetic fields using solenoid coil induced uniform quench distribution for over all stripes and simultaneous quench in all elements for current limiting of YBCO film was realized. We have achieved resistive fault current limiter of 1.2kV/20A rating using magnetic field.

• Transactions on Electrical and Electronic Materials
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• v.9 no.6
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• pp.255-259
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• 2008

The magnetic field application effect on resistance of a high-$T_c$ superconducting (HTSC) element comprising a flux-lock type superconducting fault current limiter (SFCL) was investigated. The YBCO thin film, which was etched into a meander line using a lithography, was used as a current limiting element of the flux-lock type SFCL. To increase the magnetic field applied into HTSC element, the capacitor was connected in series with a solenoid-type magnetic field coil installed in the third winding of the flux-lock type SFCL. There was no magnetic field application effect on the resistance of HTSC element despite the application of larger magnetic field into the HTSC element when a fault happened. The resistance of HTSC element, on the contrary, started to decrease at the point of four periods from a fault instant although the amplitude of the applied magnetic field increased.