• Progress in Superconductivity and Cryogenics
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• v.16 no.3
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• pp.10-14
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• 2014

Due to continuous increase of electric power consumption, couple of resolutions for improving accuracy in power system like line separation are being studied. The increase of the power demand can cause problems such as supply difficulties of the electricity and broadband outages, failure, etc. When a fault occurs in the power system, a fault current also increases. Fault current creates problems like reduction of lifespan and failure on the power system. In order to resolve these problems, the reduction of initial fault current using the characteristics of superconducting element was applied to fault current limiter. We applied the system to high speed fault current limiter. We found that the superconducting element effectively reduced initial fault current and the fault current was limited by changing operation of high speed interrupter.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.168-170
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• 2001

This paper presents the strategy of reactive power compensation which directly improves voltage stability. Voltage stability index that serves as an indirect assessment of voltage stability margin is derived from M.G.C.F. (Modified Generalized Curve Fit) algorithm incorporating load model. Weak buses are ranked by this stability index, and amounts of reactive power compensation are determined by function of reactive power and stability index. Using the proposed strategy, all load buses can be prevented from voltage collapse gradually. A simple illustrative example is given as well as simulation results obtained on 5 bus test system and 19 bus real power system.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2130-2132
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• 1998

With the increasing demands for clean environment, development of air cleaning systems has been received increasing attention. EP is usually used for air cleaning in the coal power plant. One of the key technology in the EP is high voltage pulse power supply, which affects the performance of the overall system. In this study, high voltage micro pulse power supply for the EP is developed for a 500MW coal power plant. The power supply has a dc source and a pulse one. The ratings of the dc and pulse source are 60kV, 800mA and 70kV, 400mA respectively.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1908-1910
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• 1997

The electric and magnetic fields (EMFs) near 345/154 kV overhead transmission lines were measured. The average values of maximum electric field and magnetic field for 44 transmission lines were 1.11 kV/m and 24.5 mG, respectively. These values were lower than any standards of advanced countries. The EMFs of distribution lines and substation, and electric appliances were also measured and compared with those of transmission lines.

• Journal of Power System Engineering
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• v.11 no.1
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• pp.39-44
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• 2007

The purpose of this study is to verify availability of the acoustic emission in-situ monitoring method to the internal leak and operating conditions of the major valves at nuclear power plants. In this study, acoustic emission tests are performed when the pressurized temperature water and steam flowed through glove valve(main steam dump valve) and check valve(main steam outlet pump check valve) on the normal size of 12 and 18". The valve internal leak monitoring system for practical field was designed. The acoustic emission method was applied to the valves at the site, and the background noise was measured for the abnormal plant condition. To improve the reliability, a judgment of leak on the system was used various factors which are AE parameters, trend analysis, frequency analysis, voltage analysis and amplitude analysis of acoustic signal emitted from the valve operating condition internal leak.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.707-710
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• 2005

This paper presents a 3kW grid-connection photovoltaic power generation system and its topology. Photovoltaic system must provide the sinusoidal output voltage wave for unity power factor High frequency switching converters are becoming more popular because of several benefits which are essential in power conversion system. This paper introduces a high speed digital controller using TMS320F2812 DSP chip which can be used for high frequency switching converters. The experimental results of the proposed PWM Inverter demonstrates its high performance with unity input power factor having very low distorsion in input current waveforms and good dynamic characteristics at full load.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.102-105
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• 2005

For transferring the primary power to the secondary one, the high frequency series resonant converter has been widely used for the contactless power supply system. However, the high frequency series resonant converter has the disadvantages such as the low efficiency, the high voltage gain characteristics and deviation of the phase angle in the overall load range. To improve this disadvantage, In this paper, the characteristics of the high efficiency and unit voltage gain as well as in phase are revealed in the proposed three-level LCLC ( Inductor - Capacitor - Inductor -Capacitor)resonant converter. The results are verified on the simulation based on the theoretical analysis and the 4kW experimental prototype.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.10
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• pp.67-72
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• 2010

G8 summit meeting held in July 2008 decided to set up a long-term goal, by 2050, reducing the world greenhouse emissions by half of those emitted in 1990. In November 2009, the Government announced to reduce the national $CO_2$ emission by 30[%] of BAU by 2020. Electric power industries in Korea produce most of their electricity by burning fossil fuels, and emit approximately 28[%] of national $CO_2$ emissions. Monitoring the $CO_2$ emissions. Monitoring the $CO_2$ emission of electric power plants is very important. This paper presents a method to calculate the hourly $CO_2$ emission for a thermal power plant burning mixture of coal and oil using the performance test data and coal-oil mix rate. An example of $CO_2$ emission calculation is also demonstrated.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.77-79
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• 2007

The phase angle of the utility voltage is used in current control of grid-tied fuel cell power converter. Therefore if the detection of phase angle is a problem, Current control is affected by the distorted phase angle. This paper presents a problem of synchronous reference frame PLL algorithm for single-phase systems and proposes compensated synchronous reference frame PLL algorithm. The proposed method helps power quality improvement of grid-tied fuel cell power converter under distorted utility conditions. Simulation and experimental results are presented to demonstrate the validity of the proposed method.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.746-748
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• 1996

House load operation (HLO) is the Willy of a plant to continue to operate while completely separated from the transmission system. HLO capability is recently adopted as basic design requirement for nuclear power plants, since HLO capability increases the plant availability and power system reliability. However, HLO results in the voltage and frequency transients to motors and pumps. This paper presents the computer simulation results such as the transient speeds, voltages, and control system responses of turbine/g enerator during HLO. This paper also suggests the plant design features required for HLO capability and the transient speed/vlitage limits caused by HLO.