• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.12
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• pp.1000-1003
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• 2012

The superconducting fault current limiter (SFCL) can quickly limit the fault current shortly after the short circuit occurs and recover the superconducting state after the fault removes and plays a role in compensating the voltage sag of the sound feeder adjacent to the fault feeder as well as the fault current limiting operation of the fault feeder. Especially, the flux-lock type SFCL with an isolated transformer, which consists of two parallel connected coils on an iron core and the isolated transformer connected in series with one of two coils, has different voltage sag compensating and current limiting characteristics due to the winding direction and the inductance ratio of two coils. The current limiting and the voltage sag compensating characteristics of a SFCL using a transformer winding were analyzed. Through the analysis on the short-circuit tests results considering the winding direction of two coils, the SFCL designed with the additive polarity winding has shown the higher limited fault current than the SFCL designed with the subtractive polarity winding. It could be confirmed that the higher fault current limitation of the SFCL could be contributed to the higher load voltage sag compensation.

• Transactions on Electrical and Electronic Materials
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• v.18 no.1
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• pp.42-45
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• 2017

In this paper, a transformer type SFCL (superconducting fault current limiter) using an additional magnetically coupled circuit was suggested. Its transient fault current limiting characteristics, due to the winding direction of additional coupled circuit, were analyzed through fault current limiting tests. The suggested transformer type SFCL was composed of the primary winding, and one secondary winding wound on the same iron core together with an additional magnetically coupled circuit. That circuit consists of the other secondary winding together with the other SC (superconducting) element connected in parallel with its other secondary winding. As one of the effective design parameters to affect the transient fault current of the SFCL, the fault current limiting tests of the suggested SFCL were carried out considering the winding direction of its additional coupled circuit. It was confirmed that, through the analysis on the fault current tests of the SFCL, the quench sequence of two SC elements comprising the suggested SFCL could be adjusted by the winding direction of the additional coupled circuit.

• Transactions on Electrical and Electronic Materials
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• v.18 no.3
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• pp.159-162
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• 2017

In designing the autotransformer type superconducting fault-current limiter (SFCL), one must consider that the iron core can be saturated for the SFCL to have effective fault-current limiting operation. In this paper, to examine the saturation of the iron core comprising SFCL during the fault period, the linkage flux and the magnetizing current of the SFCL were derived from the electrical equivalent circuit with the nonlinear exciting branch. By analysis on the linkage flux versus the magnetizing current of the autotransformer type SFCL, calculated from the short-circuit tests, the design condition for the suppression of the iron core's saturation was discussed.

• Progress in Superconductivity
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• v.7 no.2
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• pp.114-119
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• 2006

High critical current density, high n value, multiple faults endurances, and fast recovery characteristics of YBCO thin films are very attractive characteristics for developing resistive type superconducting fault current limiters. But due to the limited current and voltage ratings of one YBCO module, it is needed to construct series and parallel module connections for high capacity electric networks. Especially for distribution network, more than 30 units should be connected in series to meet voltage level. So in order to construct distribution-level superconducting fault current limiter, simultaneous quench in one YBCO thin films should be realized, and furthermore, quench should be occurred in all fault current limiting units equally to avoid local heating and failures. In this paper, we proposed optimum design of YBCO thin films for fault current limiting module and technical method using shunt resistor to achieve simultaneous quench between multi current limiting units. From the analytical and the experimental results, optimal current path and thickness of shunt material was determined for YBCO thin films and shunt resistor between modules was developed. Finally, 14 kV one phase resistive fault current limiter using multi YBCO thin films was constructed and it was possible to get satisfactory test results.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.148-150
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• 2002

Recently the demand for electrical power is significantly increased due to the life improvement of customers. Correspond to the result, the transmission capacity is larger, also the fault current is significantly larger. Within the methods of limiting this fault current, the methods of using the fault current limiter is on the rise. If the Superconducting Fault Current Limiter(SFCL) is applied, then the power delivery loss doesn't exist between the plural power systems, also the fault current can be reduce. But for applying the real system, it needs to investigate the effect of SFCL before appling to real power systems. Consequently, the fault of transmission with SFCL was simulated using EMTP. It was investigated to the effect of SFCL at the 345[kV] transmission fault according to compare with the case of appling SFCL and removing SFCL.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.6
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• pp.255-258
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• 2006

We investigated the operating characteristics of the hybrid-type superconducting fault current limiter (SFCL) according to the inductance of secondary windings. The hybrid type SFCL consists of a transformer that has a primary winding and a secondary winding with serially connected $YBa_2Cu_3O_7$ (YBCO) films. The resistive-type SFCL has difficulty when it comes to raising the capacity of the SFCL due to slight differences of critical current densities between units and structure of the SFCL. The hybrid-type SFCL with closed-loop is able to achieve capacity increase through the electrical isolation and reduction of the inductance of the secondary winding with a superconducting element of the same critical current. On the other hand, the current limiting characteristics were nearly identical in the hybrid-type SFCL with open-loop compared to closed-loop, but quench time was longer than the hybrid-type SFCL with closed-loop. We confirmed that the capacity of the SFCL was increased effectively by the reduced inductance of the secondary winding. In addition, the power burden of the system also could be lowered by reducing the inductance of secondary winding.

• 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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.3
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• pp.191-195
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• 2015

Inside the existing superconducting cables, the superconducting wire carries a loss-free current, and the cable former (the stranded copper wire) bypasses the fault current to prevent damage and loss of the superconducting cable when the fault current is applied. The fault-current-limiting-type superconducting cable proposed in this paper usually carries a steady current; but in a fault state, the cable generates self-resistance that makes the fault current lower than a certain width. That is, the superconducting cable that transmitted only a low voltage and a large capacity power repetitively limits the fault current, as does a superconducting current limiter. To complete this structure, it is essential to investigate the mutual resistance relationship between the superconducting wires after applying a fault current. Therefore, in this paper, one kinds of superconducting wires (a wire without a stabilization layer) were connected parallel 4 tapes, respectively; and after applying a fault current, the current, voltage, resistance and thermal stability of the HTS thin-film wires were examined.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.21-22
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• 2008

The increase of fault current due to larger power demand has caused the capacity of power machines in grid to increase. To protect the power system effectively from the increased fault current, the superconducting fault current limiter (SFCL) have proposed one of several countermeasures. Therefore, to introduce SFCL into power distribution system, the position of SFCL in power distribution system is selected among some cases. Each position changes fault current limiting characteristics and SFCL's requirement. In this paper, the characteristics of limiting fault current according to installed SFCL's location in power distribution system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.296-297
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• 2005

We have investigated the quench performance of shunt reactors in the parallel connection of resistive type superconducting fault current limiter (SFCL) components based on YBCO films. To increase voltage rating, components are connected in series and to increase current level, they are connected in parallel. This method has cauesd the unbalanced quench between each components. To improve the problem, we have compared the quench properties between the current limiting components without and with shunt reactors connected in parallel. To improve the quench performance, across individual SFCL components connected the shunt reactor in parallel. The components with shunt reactors successfully produced simultaneous quench, resulting from the bypass of the fault current in the direction of the shunt reactor.