• Journal of Electrical Engineering and Technology
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• 제7권5호
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• pp.659-663
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• 2012

The application of large power transformer into a power distribution system was inevitable due to the increase of power demand and distributed generation. However, the decrease of the power transformer's impedance caused the short-circuit current of the power distribution system to be increase thus, the higher short-circuit current exceeded the cut-off ratings of the protective devices such as circuit breaker. To solve these problems, several countermeasures have been proposed to protect the power system effectively from higher fault current and the superconducting fault current limiter (SFCL) has been expected to be the promising countermeasure. In spite of excellent current limiting performances of the SFCL, on the other hand, the efforts to apply the SFCL into power system has been delayed due to both the limited spaces for the SFCL's installation and its long recovery time after the fault removal. In order to solve these problems, a hybrid SFCL, which can perform either first half cycle limiting of first half cycle non-limiting operation, has been developed by corporation of LSIS (LS Industrial System) and KEPCO (Korea Electric Power Corporation). In this paper, we tried to requirements hybrid SFCL by PSCAD/EMTDC. Simulation results of our analysis of the hybrid SFCL is that its accompanied the characteristics both the limit the fault current and quick recovery caused by the less impact from superconductor.

• 전기학회논문지
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• 제62권7호
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• pp.925-930
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• 2013

The fault current of the power transmission system is greater than that of the power distribution system. Therefore, the introduction of superconducting fault current limiter (SFCL) is more needed to reduce the increased fault current. The trigger-type SFCL consists of the high-temperature superconducting element (HTSC), the current limiting reactor (CLR) and the circuit breaker (CB). The trigger-type SFCL can be used to supplement the disadvantages of the resistive-type SFCL. The operation characteristics of the current ratio differential relay which is usually applied to the protection device of the power transmission system are expected to be affected under fault conditions and the applicability of the trigger-type SFCL. In this paper, we analyzed the operating characteristics, by the fault conditions, between the current ratio differential relay for line protection and the trigger-type SFCL in the power transmission system through the PSCAD/EMTDC simulation.

• 한국전기전자재료학회논문지
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• 제24권5호
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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.

• 한국전기전자재료학회논문지
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• 제24권2호
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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.

• Progress in Superconductivity
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• 제6권1호
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• pp.46-51
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• 2004

We fabricated a resistive type superconducting fault current limiter (SFCL) of 3-phase $6.6 kV_{rms}$ / rating, based on YBCO thin films grown on sapphire substrates with a diameter off inch. Each element of the SFCL was designed to have the rated voltage of $600 V_{rms}$ $/35A_{rms}$. The elements produced a single phase with 8${\times}$6 components connected in series and parallel. In addition, a NiCr shunt resistor of 23 $\Omega$ was connected in parallel to each of them for simultaneous quenches between the elements. Prior to investigating the performance of the 3 phase SFCL, we examined the quench characteristics for 8 elements connected in series. For all elements, simultaneous quenches and equal voltage distribution within 10% deviation from the average were obtained. Based on these results, performance of the SFCL for single line-to-ground faults was investigated. The SFCL successfully limited the fault current of $10 kA_{ rms}$ below 816 $A_{peak}$ within 0.12 msec right after the fault occurred. During the quench process, average temperature of all components did not exceed 250 K, and the SFCL was totally safe during the whole operation.

• Transactions on Electrical and Electronic Materials
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• 제18권1호
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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.

• 조명전기설비학회논문지
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• 제23권2호
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• pp.77-81
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• 2009

병렬연결된 두 코일을 가진 자속구속형 초전도 전류제한기의 사고발생시 철심의 포화를 억제하기 위한 방안으로 공극을 도입하였다. 하지만, 공극의 도입으로 인해 자화전류가 증가하게 되어 자속구속형 초전도 전류제한기의 임피던스 감소를 초래하게 된다. 본 논문에서는 공극유무에 따른 병렬연결된 두 코일을 가진 자속구속형 초전도 전류제한기의 전류제한 특성을 등가회로와 실험결과에 대한 비교분석을 통해 공극도입의 장.단점을 확인하였다.

• 전기학회논문지
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• 제64권3호
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• pp.357-364
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• 2015

The power system configuration is changed to solve increasing power demand. This changes in power system configuration with mesh-, network grid generate the problem of fault current increase. Superconducting fault current limiter (SFCL) has been expected the one of the solutions to solve this problem. And there has already been reported much to the application and research of SFCL in the power distribution system. However, the application and research of SFCL are insufficient in a transmission power system. Also, the fault current limiting effect by the SFCL varies with installation location of SFCL. Therefore, this paper constructed the power transmission system through experiment and analyzed installation location method of SFCL using the current rate of each circuit breaker (CB) according to fault location.

• 전기학회논문지
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• 제60권1호
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• pp.20-25
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• 2011

This paper analyzed the application of Superconducting Fault Current Limiter (SFCL) on 22.9 [kV] bus tie in a power distribution system. Commonly, the parallel operations of power main transformers offer a lot of merits. However, when a fault occurs in the parallel operation of power main transformer, the fault currents might exceed the interruption capacity of existing protective devices. To resolve this problem, thus, the SFCL has been studied as the fascinating device. In case that, Particularly, the SFCL could be installed to parallel operation of various power main transformers in power distribution system of the Korea Electric Power Corporation (KEPCO) on 22.9 [kV] bus tie, the effect of the resistance of SFCL could reduce the increased fault currents and meet the interruption capacity of existing protective devices by them. Therefore, we analyzed the effect of application and proposed the proper impedance of the R-type SFCL on 22.9 [kV] bus tie in a power distribution system using PSCAD/EMTDC.

• 전기학회논문지
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• 제60권2호
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• pp.239-244
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• 2011

Due to large demand, the increase of fault current has caused the capacity of power machines in power grid to increase. Among several countermeasures, the superconducting fault current limiter (SFCL) has been noticed as one of the promising countermeasures to solve these problems. However, in spite of excellent current limiting performances of the SFCL, the application of SFCL to power system has been delayed due to both the limited space for the SFCL's installation and its longer recovery time after the fault removal. In order to solve these problems, a hybrid type SFCL was developed. In this paper, we studied the operation characteristics of the hybrid SFCL with first half cycle non-limiting operation by modelling using PSCAD/EMTDC and experiment. It was shown through the simulation using PSCAD/EMTDC and the simulated experiment that the fault current limiting and the fast recovery operations of the hybrid SFCL with the first half cycle non-limiting operation were achieved.