• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.157-159
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• 2008

This paper describes modeling and analysis of magnetic inrush for a 765kV transformer using EMTP-RV. EMTP-RV generates the core flux and thus helps show the behavior of the core, i.e. hysteresis characteristics. The results of three kinds of the magnetic inrush such as initial inrush, sympathetic inrush, and recovery inrush are included. This modelling can help the design of a protection relay for a transformer.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.255-257
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• 2005

This paper proposes a compensating algorithm of a measurement torrent transformer (CT) using DSP. The core flux is calculated and then magnetizing current is estimated in accordance with the flux-magnetizing current curve. The core loss current is obtained with the core loss resistance and the secondary voltage. The correct secondary current is estimated by adding the exciting current to the measured secondary current. The performance of the proposed algorithm was tested using EMTP generated data. The experiment on the real CT was conducted using the prototype compensated system based on a digital signal processor. The results indicate that the algorithm can increase the accuracy of the measurement CT significantly.

• 대한예방의학회:학술대회논문집
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• 2002.10a
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• pp.352-353
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• 2002

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.636-640
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• 2002

Acoustic coupled combustion instability, which is one of the most undesirable phenomena in the development of liquid propellant rocket engine, can cause serious damage to a rocket itself, and must be avoided by all means. Unfortunately, KSR-III rocket went through combustion instability during engine start at the propulsion test article No.2. To resolve the problem, time sequence (cyclogram) has been changed, and baffle system has been applied. In consequence of change, stable combustion was achieved.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.236-237
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• 2006

A microgrid is a new type of power system which is formed by the interconnection of small generator to distribution systems. Microgrids are able to supply electric power to their loads independently, which is called with islanding operation, even if they're separated from the power system. As a result, microgrids must be equipped with specific islanding detection schemes for the islanding operation of microgrids. This paper studies an islanding detection method considering reactive power. The proposed method is dealing with the reactive power of the cable which connects between a microgrid and a power system. To show the validity of the proposed method, many islanding operation cases are tested by varying the load conditions of microgrids.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.208-209
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• 2006

Voltage Transformer is used to transform high voltage into low voltage to input signal of protection relay. Most of the Voltage Transformers use the iron core which maximizes the flux linkage. The ratio of the Voltage Transformer depends on the transformer turns ratio. The current which flows in the Voltage Transformer has non-linear characteristic caused by hysteresis of the iron core, it causes a voltage loss in the winding impedances which makes measurement errors. This paper describes an error compensation method considering hysteresis characteristic. The proposed compensation method improves error by calculating the primary current from the exciting current of the hysteresis loop in the Voltage Transformer, compensating the voltage loss.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.363-365
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• 2006

This paper proposes an estimation method for a circulating current of a Y-${\Delta}$ Transformer. The delta winding current can be decomposed into the two components i.e. a non-circulating component and a circulating component. The former can be estimated using the line currents. However, the latter can not be estimated directly using the line currents. A first order differential equation for the circulating current is derived by applying the Kirchhoff's voltage law on the loop of the delta side. The circulating current can be estimated by the solving the differential equation. The performance of the proposed algorithm is investigated under various conditions including magnetic inrush and over-excitation. The algorithm can estimate the circulating current very accurately even under magnetic inrush and over-excitation.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.180.2-181
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• 2003

Capsaicin (8-methyl-N-vanillyl-6-nonenamide), a pungent ingredient of hot chili peppers, has been reported to possess substantial anticarcinogenic and antimutagenic activities. In the present study. we investigated the effects of capsaicin on pulmonary metastasis of B 16-F10 murine melanoma cells. as well as its mechanism of action. Capsaicin (i.p.. 2.5mg/kg) suppressed the number of lung colonies (58％) in experimental lung metastasis assay. (omitted)

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09b
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• pp.1355-1355
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• 2005

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2004.11a
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• pp.112-112
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• 2004