• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.855-858
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• 1988

Two methods for probabilistic maintenance scheduling are developed and compared ; one with operation and supplied-shortage cost and other with risk level of LOLP. Based on the real economic power dispatch, quadratic optimal maintenance conditions are obtained and simple amtrix equations are suggested for solutions. Both methods are compared in a sample system of 26,000 [MW] peak and 32,000 [MW] generation capacity.

• 한국가스학회:학술대회논문집
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• 2007.04a
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• pp.85-91
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• 2007

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.117-119
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• 1995

For an effective application of the cogeneration system for commercial and industrial buildings, we need to develop a relevant model to determine the long-term based optimal sizing of the cogeneration system considering electrical and thermal load demands, buy and sell contracts with electric utility and the annual production cost. In assessing the optimal sizing of cogeneration, we have to consider both economic parameters and their capacity expansion for the increased electrical and thermals demand in the future. In this paper, we propose a mathematical model for the optimal sizing of cogeneration systems considering annual production costs and other economic parameter such as, lifetime of the equipment, time value of the capital, etc. In the case study, we thoroughly examine the effects of the economic parameters and determine the optimal size of the sample system. In addition, we calculate the payback period of the cogeneration investment.

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.620-622
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• 1995

This paper presents an analysis of the voltage stability when the contingency is occured in the power system. The evaluation of voltage stability is examined by the system identification based on T/L losses and percent indicator which represents how relatively far-off from the voltage collapse. When contingency happens, the bus voltages can be calculated using the EMTP and then, the time-interval in contingency is linearized between the known operating points in nose curves. For the sample study, the 5-bus and 7-bus systems are selected and, countermeasures for the contingency are established in view of the voltage stability.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.958-960
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• 1998

This paper presents an application of power system stabilizer for a 5Kw Motor-Generator Set. The power system which was consisted of 5Kw Motor-Generator Set. Excitation system, Governor system and PSS was used for the performance test. The method by changing the PSS gain to allocate properly pole-zero positions was used for setting PSS parameter value. The result of the experiment was satisfactory.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.186-188
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• 2005

This paper presents a method of finding the optimal capacity of renewable energy in power system to prepare Kyoto-protocol. In order to determine the capacity of renewable energy, this paper finds a amount of CO2 emission and capacity of power reduction for each energy type. The proposed method performs economic dispatch including the existing facilities, renewable energy and Emission trading, and finds optimal capacity of renewable energy Power satisfying minimum total cost. Finally, the proposed idea is demonstrated with a case study.

• Proceedings of the Korean Society of Potoscience Conference
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• 2005.06a
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• pp.136-136
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• 2005

• Journal of the Korean Vacuum Society
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• v.14 no.1
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• pp.24-28
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• 2005

A typical method for obtaining poly-Si films is the solid phase crystallization(SPC) of amorphous Si. Advantages of SPC are uniformity, process quality and low cost of production. However, high process temperature and long process time prevent the employment of SPC process on thermally susceptible glass substrate. In this parer, we propose a new method that applies an alternating magnetic field during crystallization annealing in an alternating magnetic field crystallization(AMFC) system for lowering process temperature and shorter process time of SPC. When we crystallized, in the case of SPC, annealing time is 24 hours at 570℃. But in the case of AMFC, annealing time is only 20 minutes at the same temperature.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.1081-1086
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• 2010

The general soil nailing support system may result in excessive deformations particularly in an excavation zone of the existing weak subsoils. Pretensioning the soil nails then, could play important roles to reduce deformations mainly in part of the nailed-soil excavation system as well as to improve local stability. Morever, soil nails are installed underneath roads, underground structures, and subway structures, thereby resulting in difficulties in nail remval after completion of temporary soil nailed walls. Hence, to date, in order to solve the technical difficulties and avoid legal issues related to the construction of soil nails underneath the surrounding areas and structures, the removable soil nailing system has been developed and used. But, Therefore, a new soil nailing technique called Removable Post-tensioned Soil Nailing(RPTN) system has been developed in the current study. In this study, an investigation of the RPTN system has been conducted by carrying out field measurement. Hence, the RPTN system can reduce ground displacement and enhance stability of the soil nailed walls.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.515-517
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• 2001

The efficient and rational transmission rate system is one of the crucial factors in creation of fair and competitive electricity market. Transmission charge can be largely categorized into the line usage charge, system reliability maintenance charge, access charge and others. Therefore, transmission rate structure should be able to reflect these cost components reasonably. This Paper suggests an approach that could be used for the reasonable calcuation of transmission reliability costs with reflection of line sensitivity and line outage rate.