• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1492-1494
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• 2015

분산전원 연계기준에 따라 변압기 1차 중성점을 접지운전시 Y-Y-3Limb, $Y-{\Delta}$결선방식은 비대칭 계통전압에 의해 순환전류가 발생된다. 이러한 순환전류는 상별 전류에 영향을 주어 보호계전기 오동작 및 전력량계 오차를 발생시킨다. 따라서 순환전류로 인한 전력계산의 문제를 해결하기 위해 신동파워이론을 만들었다. 본 이론의 핵심은 비대칭 3상 전압과 변압기 결선 및 구조에 의해 발생되는 영상 임피던스(R+jX) 해석을 통해 중성선의 순환전류를 계산하였다. 따라서 정확한 전력계산을 위해 순환전류에 의해 발생되는 상별전류를 보정하는 새로운 이론을 소개 하고자 한다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2000.11a
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• pp.251-256
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• 2000

The assessment of the condition of a transformer winding which is suspected of having suffered short circuit damage can be difficult. Conventional test such as winding resistance, magnetisation current or insulation resistance will only detect damage if a permanent electrical fault exists. Visual inspection of windings necessitates the removal of oil and in many cases only a very small proportion of the winding can be seen. We describe the characteristics. As the front rise time of recurrent-surge generator pulse less than 1000ns and the peak value of pulse is about 500V, we have the good results of detecting winding deformation in the LVI test of transformers.

• Journal of Korea Multimedia Society
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• v.20 no.7
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• pp.1046-1053
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• 2017

We propose a design method of high accuracy power measuring device and the method of securing the reliability of the measured data. As a design method for the development of the high accuracy power measuring device, the circuit was made by reflecting the high accuracy power measuring ICs and the CT (Current Transformer). To ensure the reliability of the power meter, we requested to the watt-hour meter certified testing organization to measure the error rate, and the error rate of active power based on the "Wattmeter Technical Standard(Revision notify 2014-283)" was measure, and the error rate was confirmed to be less than 0.1%.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.372-374
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• 2006

This paper reported the experimental results of the 2 stage converter using a Buck converter and a soft switching dc-to-dc converter that employs two separate transformers. A 2 stage converter module is designed with the specifications of an 3.3V output voltage, 20A output current, 66W output power and 36-75V input voltage. A prototype converter module is successfully implemented within 85.2% efficiency and 3% voltage regulation for the entire input voltage range, thereby demonstrating its application potentials to future telecommunication electronics.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.348-351
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• 2006

연료전지로부터의 낮고 변동폭이 큰 전압을 안정되게 승압시키기 위하여 부스트 컨버터가 사용되고 있으며 전기적인 절연이 요구되지 않는 응용에서는 손실, 가격 및 부피 상승의 원인이 되는 고주파변압기가 없는 무변압기형의 부스트 컨버터가 장점을 갖는다. 본 논문에서는 $6{\sim}8$배의 실제 사용 가능한 승압비를 가지며 입출력 전류리플이 매우 작은 새로운 무변압기형 부스트 컨버터를 제안하고 모의실험을 통하여 그 타당성을 검증한다.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.242-244
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• 2006

본 논문은 LCD Backlight 인버터 구동 응용을 위한 다중 램프 점등 시 트랜스포머 소자 수 감소를 이를 수 있는 전류평형 트랜스포머의 구조 및 형상에 관한 것으로서, 제안된 트랜스포머 구조는 기존의 트랜스포머 구조 방식에 비해 소자 수가 줄어들어, LCD Backlight 인버터의 원가를 저감 할 수 있는 트랜스포머 구조 및 형상에 관한 것이다.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.466-469
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• 2002

Many power plants in the thermal and hydraulic utilities, the pulp and the paper industry are faced with high maintenance and down time due to the aged excitation system. For the life extension of the aged power plants, the static excitation system with SCPT type had been developed by KEPRI(Korea Electric Power Research Institute) This paper will discuss the design conception and the application results of system which includes the phase controlled rectifiers of the shunt type, SCPT and redundant analog controller.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.337-338
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• 2010

LCD TV의 화면을 균등한 휘도로 표현하기 위해 기존의 구동회로는 다 채널의 LED를 정전류로 제어하는 DC/DC 컨버터가 각각 적용되었고, 이는 원가 상승 및 효율 저하의 원인이 되었다. 이를 해결하기 위하여 본 논문에서는 각 LED 채널에 적용되는 DC/DC 컨버터 없이 트랜스포머와 커패시터를 이용하여 모든 LED 채널의 정전류 제어가 가능한 고효율 저가격형 구동회로를 제안하고, 이에 대한 이론적 해석을 제시한다. 최종적으로 제안 회로를 46" LCD TV 백라이트에 적용하여 그 실험 결과를 바탕으로 제안 회로의 타당성을 검증한다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.05a
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• pp.123-128
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• 1996

As electrode materials like as Cu-Pb, Cu-Bi, WC-Ag, W-Ag for vacuum circuit breaker have high chopping current or bad insulation-recovery characteristics, it can affect induction machinery like as transformer and motor. To produce low surge electrode material, it have been suggested Co-Ag-Te electrode which were infiltrated with Ag-Te intermetallic compound into sintered Co matrix in vacuum. In this paper, we would like to represent that production method and microstructure of Co-Ag-Te electrode material in each condition. The microstructure and characteristics of Ag-Te intermetallic compound and Co-(Ag-Te) electrode were investigated by using optical microscope, SEM, XRD, EPMA.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.361-363
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• 1999

This paper proposes an SSSC based on 3-level half-bridge inverters. The dynamic characteristic of the proposed SSSC was analyzed by EMTP simulation, assuming that the SSSC is inserted in the transmission line of the one-machine-infinite-bus power system. The proposed SSSC has six 3-level half-bridge inverters per phase, which operates in PWM mode. The proposed SSSC generates a quasi-sinusoidal output voltage by 90 degree phase shift to the line current. The proposed SSSC does not require the coupling transformer for voltage injection, and has a flexibility in operation voltage by increasing the number of series connection.