• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.312-315
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• 2003

Basic design of RC-GCTs (Reserve-Conducting Gate-Commutated Thyristors) by novel punch-through (PT) concept with 5,500v rated voltage is described here. A PT and NPT (non punch-through) concept for the same blocking voltage has been compared in detail. The simulation work indicates that GCT with such PT design exhibits that the forward breakdown voltage is 6,400V which is enough for supporting 5500V blocking. Additionally, the real IGCT turn-off in the mode of PNP transistor has been realized. However, the carrier extraction from N-base to gate terminal will be drastic slowly in terms of NPT structure except for the high on-state voltage drop.

• 대한전기학회논문지:전력기술부문A
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• 제51권2호
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• pp.93-101
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• 2002

This paper describes a new method for determining the permissible operating range of DG(Distributed Generation) when DG is introduced into power distribution systems of which the voltage is controlled by LDC(Line Drop Compensator). Much of the DG installed during the next millennium will be accomplished through the reconstruction of the electric power industry. But in that case, it is difficult to properly maintain the terminal voltage of low voltage customers by using only LDC. This paper presents a method for determining the permissible operating range of DG for proper voltage regulation of power distribution systems with LDC. Proposed method has been applied to a 22.9 kV model and practical distribution systems, and its result is almost identical with the simulation result.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 A
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• pp.19-21
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• 2001

Nowadays, small scale DGS(Distributed Generation System), as a wind power generation or photovoltaic generation, becomes to be introduced into the power distribution system. But in that case it is difficult to properly maintain the terminal voltage of low voltage customers by using only LDC(Line Drop Compensator). So, it is necessary to determine the permissible operation limit of the introduced DGS for proper voltage in distribution system. In this paper clarifies the relationship between LDC voltage regulation principle and real, reactive power of DGS, and examines the permissible operation limit of the introduced DGS in distribution system which the voltage is controlled by LDC.

• Journal of Power Electronics
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• 제15권6호
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• pp.1601-1608
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• 2015

This paper presents a PQ control strategy for micro grid inverters with axial voltage regulators. The inverter works in the voltage-controlled mode and can help improve the terminal power quality. The inverter has two axial voltage regulators. The 1st regulator involves the output voltage amplitude and output impedance, while the 2nd regulator controls the output frequency. The inverter system is equivalent to a controllable voltage source with a controllable inner output impedance. The basic PQ control for micro grid inverters is easy to accomplish. The output active and reactive powers can be decoupled well by controlling the two axial voltages. The 1st axial voltage regulator controls the reactive power, while the 2nd regulator controls the active power. The paper analyses the axial voltage regulation mechanism, and evaluates the PQ decoupling effect mathematically. The effectiveness of the proposed control strategy is validated by simulation and experimental results.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.184.3-184.3
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• 2010

This study suggests a modeling of grid-connected wind turbine generation systems and performs simulation according to increase/decrease of real wind speed. MATLAB & SIMULINK implemented modeling of grid-connected wind turbine generation system. Terminal voltage, grid voltage, and active/reactive power shall be observed following the performance of simulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 전문대학교육위원
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• pp.92-95
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• 2004

Power transformer is an important apparatus in transforming and delivering the power in a power system. It shows less accident ratio than other system apparatus, but once the accident occurs, it causes long-term operation stoppage and economic loss. It brings high bad spillover effects. Therefore, the role of protective relaying, which is to prevent internal fault a power transformer is highly important. This study proposed advanced algorithm that can clearly determine internal fault of the power transformer and magnetizing inrush, through numerical analysis by using the terminal voltage and input output current.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 추계학술대회 논문집
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• pp.321-323
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• 2008

This study suggests a modeling of grid-connected wind turbine generation systems and performs simulation according to increase/decrease of real wind speed. MATLAB/Simulink implemented modeling of grid-connected wind turbine generation system. Terminal voltage, grid voltage, and active/reactive power shall be observed following the performance of simulation.

• 전자공학회논문지A
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• 제28A권9호
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• pp.700-707
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• 1991

Transmission line crosstalk of a printed circuit baord terminated with the linear resistive and nonlinear terminal network is analyzed. Based on a quasi-static approximation, crosstalk voltage is computed in frequency domain by applying the modal analysis. A scheme to calculate the maximum crosstalk voltage for a line terminated with the nonlinear digital gate is proposed. And also, crosstalk quantities are numerically obtained for the microstrip and strip line, and compared with the experimental data to validate relevance of this method.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2000년도 춘계종합학술대회
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• pp.132-134
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• 2000

This paper presents self-oscillating mixer(SOM) with simple structure which includes dc source, a cross type groove, and a three terminal GaAsFET. By using parasitic elements such as cooper wires, If level of the active antenna is increased. In order to include active device into FDTD analysis, equivalent voltage source are used to substitute for the active device and to describe the voltage-current relationships. This approach is applied to analyze SOM theoretically.

• 대한전기학회논문지
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• 제40권6호
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• pp.619-625
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• 1991

Phenomena of streaming electrification of insulting oil(T.O) is studied where the oil is contacted with solid insulating materials when it is pumped through a circulating system in a large power transformer. The leakage current, the electrical potential at the neutral terminal point of the transformer and the surface electrical potential of the oil are investigated. And the leakage current from the neutral terminal point is measured as a function of a bias polarity applied to a transformer case to investigate the polarty of ion which is absorbed in the case at the interface between the case and oil. As a result, it is found that insulating materials, and it is suggested that the leakage current is the sum of the relaxation current by positive charge from insulating oil to the neutral terminal point and by electrification current from negative charge electrified by the contact with solid insulating materials.