• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.11
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• pp.742-747
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• 1999

On-line diagnosis system has been developed and is now applied the detection of shorted turns in the field winding of large generator. This system consists of data aquisition system and display PC. The data aquisition system detects voltage waveforms from flux probe sensor installed in the stator slot. The display PC shows theshorted-turn situation of generator rotor winding. A shorted-turn diagnosis test wasperformed on five gas turbine generators at the Seoinchon combined cycle power plant. The test was conducted using an new diagnosis system and digital oscilloscope which can identify the pole location, the slot number and the number of shorted turns within each slot. It is confirmed that results of two systems are very same in the field tests.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.8
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• pp.401-406
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• 2004

In this experimentation, we investigated the characteristics of electromagnetic wave absorption of ferroxplana powder and silicone rubber composite. Ferroxplana was prepared by flux method at low temperature. The crystallization, magnetic properties and particle morphology of the obtained ferroxplana powder were investigated by using XRD, VSM and SEM. The particle size of ferroxplana powder was 2∼4$\mu\textrm{m}$ at the ratio of R=26, The coercivity and saturation magnetization of ferroxplana powder increased slightly with increase of temperature, The magnetic loss was the main factor of electromagnetic wave absorption of ferroxplana powder and silicone rubber composite, The maximum reflection loss of composite was about -l5dB below 4GHz.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.5
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• pp.232-237
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• 2001

The transition avalanche to streamer are presented in atmospheric pressure nitrogen. The results of two-dimensional simulation are obtained by using finite Elements Method combined with Flux Corrected Transport algorithm(FEM-FCT). We modeled the negative streamer which enables to propagate with out and with photoionization. The results of simulation without photoionization and with photoionization are compared. We show that photoionization plays important roles not only in streamer formation but also in streamer propagation.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.186-189
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• 1996

Convential inrush current detection method is used to harmonic restraint method by filtered second frequency component. Nowadays this technique must be modified because harmonics are occurred in steady state of power system. A purpose of this study is to develop of inrush current detection relaying algorithm for power transformer based on flux-current derivative curve method. We used the relaying signals obtained from EMTP simulation.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.177-179
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• 1995

The hybrid type LOA is electric machine which reciprocates the mover by thrust force produced by interaction of flux between coil current and permanent magnet. In this paper, the shape of LOA is designed conceptually and calculating algorithm of leakage inductance in the stator slot and magnetizing inductance between stator and mover is obtained. Using the conceptually designed LOA, the change of flux distribution is studied in consideration with movement of a mover.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.5
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• pp.661-678
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• 2006

Products developed in this research is a software which can transfer the type of shape(.shp) into the type of ascii using the land cover data and the topography data in the metropolitan area of Seoul. In addition, it can calculate the $CO_2$ flux according to distribution of plants within the land cover data. The $CO_2$ flux is calculated by the experimental equation which is compose of the meteorological parameters such as the solar radiation and the air temperature. The net flux was shown in about $-19ton/km^2$ by removing $CO_2$ through the photosynthesis during daytime, and in 2 ton/km2 by producing it through the respiration during nighttime on 10 August 2004, the maximum day of air temperature during the period of 3yr(2001 to 2004), in the metropolitan area of Seoul. Spatial distribution of the air temperature and the wind field is simulated by substituting the middle classification of the land cover map data, upgraded by the Korean Ministry of Environment(KME), for the land-use data of the United States Geological Survey(USGS) within the Meteorological Mesoscale Model Version 5(MM5) on 10 August 2006 in the metropolitan area of Seoul. Difference of the air temperature between both data was shown in the maximum range of $-2^{\circ}C\;to\;2.9^{\circ}C$, and the air temperature due to the land use data of KME was higher than that of USGS in average $0.4^{\circ}C$. Also, those of wind vectors were meanly lower than that of USGS in daytime and nighttime. Furthermore, the hourly time series of Volatile Organic Components(VOCs) is calculated by using the Biosphere Emission and Interaction System Version 2(BEIS2) including the new land cover data and the meteorological parameters such as the air temperature and so]ar insolation. It is possible to calculate the concentration of ozone due to the biogenic emission of VOCs.

• 한국초전도학회:학술대회논문집
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• v.11
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• pp.46-46
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• 2001

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.211.2-211.2
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• 2008

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.212.1-212.1
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• 2008

• Proceedings of the Korean Nuclear Society Conference
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• 1998.10a
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• pp.138-138
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• 1998