• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.718-719
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• 2011

Lately, the demand for electrical power has been significantly increased. As a result a power transmission system has been improved. On the other hand fault current increased more than past. Superconducting fault current limiter (SFCL) is one of the solutions to limit fault current. However, SFCL's research has not advanced in a power transmission system fully. Therefore, we studied effect of SFCL in a power transmission system. The power distribution system is open-loop circuit, but a power transmission system is closed-loop system. Consequently, Fault current in a power transmission system is larger than fault current in a power distribution system. we exerimented a simple closed-loop power transmission system circuit.

• KIEE International Transactions on Power Engineering
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• v.4A no.2
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• pp.84-90
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• 2004

This paper presents a new method for choosing the best line for transmission system expansion planning considering the highest reliability level of the transmission system. Conventional methodologies for transmission system expansion planning have been mainly focused on economics, which is the minimization of construction costs. However, quantitative evaluation of transmission system reliability is important because successful operation and planning of an electric power system under the deregulated electricity market depends on transmission system reliability management. Therefore, it is expected that the development of methodology for choosing the best lines considering the highest transmission system reliability level while taking into account uncertainties of transmission system equipment is useful for the future. The characteristics and effectiveness of the proposed methodology are illustrated by the case study using a MRBTS.

• KIEE International Transactions on Power Engineering
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• v.3A no.3
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• pp.119-123
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• 2003

Successful operation of power systems under the deregulated electricity market depends on the management of the transmission system reliability. Quantitative evaluation of the transmission system reliability is an important issue. Particularly, the nodal reliability indices can be of value in the management and control of congestion and reliability of the transmission system under the deregulated electricity market. In this study, a method developed for the reliability evaluation of the transmission system is presented. The Monte Carlo methods are used because of their flexibility when complex operating conditions are being considered. The usefulness and effectiveness of the proposed method are illustrated by a case study with the KEPCO system.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.1
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• pp.34-43
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• 2009

In this thesis, we explain developing processes of the power transmission system for lift truck. Conventional power transmission system had some problems such as spatial constraints or low speed and high torque problem. Because conventional power transmission system was mainly designed for high speed vehicles. In this paper we developed power shift drive axle specialized for $2.0{\sim}3.5$ ton lift truck. Innovative structure of transmission which is built in inside axle, enables to reduce system weight and size by 40% compared to the conventional power transmission system. Also, it is possible to do additional functions such as auto parking system and anti-roll back system.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.397-399
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• 2000

This paper presents a method for assessing reliability indices of transmission system. Because successful operation of electric power under the deregulated electricity market depends on transmission system reliability management, quantity evaluation of transmission system reliability is very important. The key point idea is based on that the reliability level of transmission system is equal to reliability level difference of between composite power system(HLII) and generation system(HLI). It is sure that risk indices of reliability of composite power system are larger than those of generation system. It is the reason that composite power system includes uncertainties and capacity limit of transmission lines. The characteristics and effectiveness of this methodology are illustrated by the case study using MRBTS.

• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.273-274
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• 2001

This paper presents the effects on 154kV electrical power customers' productive activities by the instantaneous voltage sag or interruption in power system. According to the survey all respondents (8customers) experienced the breakdown of facilities when instantaneous voltage sag over about twenty percents of pre-fault occurred in power system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.1
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• pp.7-15
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• 2017

Ambient Adjusted line Rating(AAR) method for overhead transmission lines considering Risk Tolerance(RT) was proposed in this paper. AAR is suitable for system operators to plan their operation strategy and maintenance schedule because this can be designed as a seasonal line rating. Several candidate transmission lines are chosen to apply the proposed method in the paper. As a result, it is shown that system reliability was significantly enhanced through maximizing transfer capability, solving the system constraints.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.171-173
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• 2002

This paper presents a power system decomposition technique for digital simulation of large power system. To decompose power system, distributed transmission line model is used. But this model can be used only for long transmission lines. In this paper, capacitor compensation method is proposed to use distributed transmission line model for short transmission line. And case study shows proposed method can be used for effective power system decompositon in digital simulation of large power system.

• Journal of the Semiconductor & Display Technology
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• v.13 no.4
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• pp.59-63
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• 2014

Previous studies have selected wireless power transmission system using 2.45 GHz of ISM band, but the researches for 5.8 GHz microwave wireless power transmission have been relatively rare. The 5.8 GHz has some advantages compared with 2.45 GHz. Those are smaller antenna and smaller integrated system for RFIC. In this paper, the 5.8 GHz wireless power transmission system was developed and transmission efficiency was measured according to the distance. A transmitter sent the amplified microwaves through an antenna amplified by a power amplifier of 1W for 5.8 GHz, and a receiver was converted to DC from RF through a RF-DC Converter. In the 1W 5.8GHz wireless power transmission system, the converted currents and voltages were measured to evaluate transmission efficiency at each distance where LED lights up to 1m. The RF-DC Converter is designed and fabricated by impedance matching using full-wave rectifier circuit. The transmission-efficiency of the system shows from 1.05% at 0cm to 0.095% at 100cm by distance.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.3
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• pp.131-137
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• 2014

It is expected that there will be delay of scheduled transmission network reinforcement and huge investment of renewable energy resources in Korea. As transmission capacity expansion delayed, supplying power to Seoul metropolitan area will not be increased as scheduled. In addition, uncertain renewable energy out of Seoul metropolitan area can cause transmission congestion in the future power system. These two combining effects will make the difference in locational marginal prices(LMP) and congestion costs increase. In that sense, this paper will analyze how much the congestion costs for Korea power system are incurred in the future power system. Most of previous approaches to analyze the congestion costs for electric power system are based on the optimal power flow model which cannot deal with hourly variation of power system. However, this study attempted to perform the analysis using market simulation model(M-Core) which has the capability of analyzing the hourly power generation cost and power transmission capacity, and market prices by region. As a result, we can estimate the congestion costs of future power system considering the uncertainty of renewable energy and transmission capacity.