• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.2
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• pp.300-304
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• 2017

Due to the introduction of various types of dispersed generations (DGs) with larger capacity in a power distribution system, the short-circuit current is expected to be increased, which more requires for the effective fault current limiting methods. As one of the promising countermeasures, the superconducting fault current limiter (SFCL) has been noticed. However, the decreased fault current by SFCL affects the operation of the overcurrent relay (OCR), representative protective device in a power distribution system. In this paper, the operation of the overcurrent relay due to the application of a SFCL in a power distribution system with DG linked by its bus line was analysed through the short-circuit tests. To analyze the effect of the SFCL application in a power distribution system with DG, the experimental simulated circuits were designed and the short-circuit tests for the power distributed system assembled with the DG, the OCR and the SFCL were carried out. Through the analysis on the short-circuit tests, the application of the SFCL in a power distribution system with DG could be confirmed to be contributed to the operational improvement of overcurrent relay.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.547-550
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• 2004

Superconducting fault current limiter(SFCL) is expected to be introduced into electric power system in future as an effective countermeasure for the increase of the short-circuit current due to the growth of the electric power system. SFCL has a merit that the fault current can be limited by the resistance generated when a superconductor transits from a superconducting state to a normal state without additional detecting device. In this paper, we investigated the resistance variance of resistive type SFCL and the fault current limiting characteristics due to the amplitude of source voltage. We could obtain the more effective fault current limiting characteristics of SFCL as the source voltage increased.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.523-526
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• 2004

According to the continuous demand for power and the growth of electric power utilities, the electric power transmission capacity was increased. The increase of the electric power transmission capacity results in an increase of the fault current level a fault happened. So the superconducting fault current limiter(SFCL) has been reached as the countermeasure for the reduction of the fault current. In this paper, we investigate the fault currents characteristics of resistive type SFCL according to fault angles when AC power source applied. As the fault angles increase, the first peak value of fault current decreased lower. On the other hand, the power burden of SFCL increased.

• 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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• 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.

• Progress in Superconductivity and Cryogenics
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• v.9 no.3
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• pp.46-51
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• 2007

The 22.9kV/630A superconducting fault current limiter (SFCL) is developed by the KEPRI-LSIS collaboration group. This resistive SFCL uses three pairs of conduction-cooled current leads. When the SFCL system is in the fault mode. the current flows 20 times more than the steady state. Therefore. it is important that the current lead is designed to have the thermal stability in order to minimize the heat input of the cold-end. This paper presents the design and performance results of a pair of conduction-cooled brass current leads considering both cases that the SFCL system operates at the steady state and the fault current.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.11
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• pp.1345-1352
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• 2012

This paper aims to evaluate the low-velocity impact responses and mechanical properties of balsa-wood and urethane-foam core materials and their sandwich panels, which are applied as the impact limiter of a nuclear spent fuel shipping cask. For the urethane-foam core, which is isotropic, tensile, compressive, and shear mechanical tests were conducted. For the balsa-wood core, which is orthotropic and shows different material properties in different orthogonal directions, nine mechanical properties were determined. The impact test specimens for the core material and their sandwich panel were subjected to low-velocity impact loads using an instrumented testing machine at impact energy levels of 1, 3, and 5 J. The experimental results showed that both the urethane-foam and the balsa-wood core except in the growth direction (z-direction) had a similar impact response for the energy absorbing capacity, contact force, and indentation. Furthermore, it was found that the urethane-foam core was suitable as an impact limiter material owing to its resistance to fire and low cost, and the balsa-wood core could also be strongly considered as an impact limiter material for a lightweight nuclear spent fuel shipping cask.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.2B
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• pp.100-107
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• 2007

Recently, a study of BcN(Broadband convergence Network) is progressing continuously, and it is important to improve the quality of the service according to subscribers because a scale of network is about to be larger. It is more important to manage QoS(Quality of Service) of all subscribers in layer 2 than layer 3 network since managing it in layer 3 network cost both additional processes and large hardware. Moreover, QoS based on Best-Effort service has been developed because tots of subscribers should use limited resource in BcN. However, they want to be supplied with different service even though they pay more charge. Therefore, it is essential to assign the different bandwidth to subscribers depending on their level of charge. The method of current Rate Limiter limits the bandwidth of each port that does not offer fair service to subscribers. The Rate Limiter proposed in this paper limits bandwidth according to each subscriber. Therefore, subscribers can get fair service regardless of switch structure. This new Rate Limiter controls the bandwidth of subscribers according to the information of learning subscriber and manages maximum performance of Ethernet switch and QoS.

• Progress in Superconductivity and Cryogenics
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• v.5 no.1
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• pp.102-102
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• 2003

• 한국초전도학회:학술대회논문집
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• v.14
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• pp.5-5
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• 2004