• 전기학회논문지
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• 제58권6호
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• pp.1071-1077
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• 2009

Because several winds cause the a fault of transmission supply, KEPCO trys to protect the the trouble and supply the power stably. Kepco find out the weak mountains by winds and strengthen the power equipment annually. Power quality is the competition power in the international world and satisfy the customer using th power Therefore this paper deals with the fault relation between winds and transmission line.

• Journal of Electrical Engineering and Technology
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• 제11권1호
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• pp.55-64
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• 2016

The development of high-speed rail (HSR) has had a major impact on the power supply grid. Based on the monitored waveforms of HSR, a pattern recognition approach is proposed for the first time in this paper to identify the operating conditions. To reduce the data dimensions for monitored waveforms, the principal component analysis (PCA) algorithm was used to extract the characteristics and their waveforms from the monitored waveforms data. The dynamic time wrapping (DTW) algorithm was then used to identify the operating conditions of the HSR. Cases studies show that the proposed approach is effective and feasible, and that it is possible to identify the real-time operating conditions based on the monitored waveforms.

• 전기학회논문지P
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• 제58권4호
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• pp.483-489
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• 2009

Electrolytic capacitors are used in variety of equipments as smoothening element of the power converters because it has high capacitance for its size and low price. Electrolytic capacitors, which is most of the time affected by aging effect, plays a very important role for the power electronics system quality and reliability. Therefore it is important to estimate the parameter of an electrolytic capacitor to predict the failure. This objective of this paper is to propose a new method to detect the rise of equivalent series resistor(ESR) in order to realize the online failure prediction of electrolytic capacitor for DC output filter of power converter. The ESR of electrolytic capacitor estimated from RMS result of filtered waveform(BPF) of the ripple capacitor voltage/current. Therefore, the preposed online failure prediction method has the merits of easy ESR computation and circuit simplicity. Simulation and experimental results are shown to verify the performance of the proposed on-line method.

• 조명전기설비학회논문지
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• 제25권1호
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• pp.70-77
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• 2011

Sewage treatment plants, consuming 1,756[GWh] which is 0.53[%] of national wide electricity consumption, is one of the electricity consuming facilites. At the research of electricity consumption and power quality analysis on sewage treatment plants, average utilization of transformer was less than 40[%] because peak load was very lower than its capacity due to excess capacity. So reduction of power loss can be achieved by transformer design optimization. The achievement in this research, is to meet reduction of power loss through optimizing the capacity and to improve as high efficiency-low loss transformer while the transformer is operating.

• 한국멀티미디어학회논문지
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• 제20권12호
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• pp.1849-1855
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• 2017

The main purpose of cooperative communications is improvement of communication quality and efficient use of transmission power. In this paper, a cooperative retransmission method is proposed, where neighbor nodes that receive messages correctly between transmit and receive nodes will participate in retransmission of the erroneous packet of the direct link. When the proposed retransmission method is used, the performance of the PER can be greatly improved. In case that the limited information is included in the NACK message, the transmit power of the retransmission packet can be reduced using the proper power control method.

• 전력전자학회논문지
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• 제7권4호
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• pp.384-394
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• 2002

본 논문은 기존의 정전력 제어 대신에 용접품질을 향상시키기 위해 새로운 제어기법을 제안하였다. 제안된 방식을 구현하기 위해 미분기하학 이론을 근거로 한 비선형 피드백 선형화 기법을 이용하여 스폿용접 시스템을 선형시스템으로 한 후 진화전략을 이용하여 PI제어기의 최적 이득을 얻는다. 진화전략은 제어파라미터 최적화 문제를 풀기 위한 방법으로 자연진화의 원리를 모방한 알고리즘이다. 시뮬레이션과 실험결과는 진화전략에 의한 가변전력 제어의 성능이 기존의 제어방법보다 훨씬 더 우수하다는 것을 보여준다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.547-549
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• 2008

This paper presents a implementation of the monitoring program for the analysis of electric consumption characteristics in home appliances, which uses a Labview program from National Instruments Corporation. It is can provide to be easy for small-scale researcher, development groups or individual researcher to analyze electric power consumption characteristics. Also, this paper apply to actual private home and then, analyze result of monitoring and a database result of power quality etc, like the power consumption form, power factor and harmonic which follow season, and time zone. For this measured the apartment where the family which is four lives in the object.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.151-153
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• 2008

This paper deals with the electric energy saving system for lighting with power conditioning, which aims at the integration of power quality improvement and energy saving. The system consists of a CCVSI(Current-Controlled Voltage Source Inverter) and VCVSI(Voltage-Controlled Voltage Source Inverter). The CCVSI is connected in parallel to a grid, which can be operated to compensate the reactive power demanded by nonlinear and variation loads. The VCVSI is connected to the CCVSI through the DC capacitor (DC side) and in series on the AC side(lighting load), which can perform the energy saving. The operation of the proposed system is confirmed through the simulation and its usefulness is discussed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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• pp.545-546
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• 2006

최근 들어 태양광, 풍력발전 등과 같은 분산전원이 배전계통 곳곳에 연계됨에 따라 전기품질이 저하될 것이라는 우려가 있다. 본 논문에서는 현재 가장 높은 보급률을 보이고 있는 저용량 태양광 발전기가 설치된 수용가를 대상으로 전기품질을 측정하고 '분산형 전원 배전계통연계 기술기준'의 전력품질 만족여부를 분석하였다. 또한 기술기준에서 정한 TDD뿐만 아니라 THD까지 측정하여 해당 지수들의 특성을 비교 분석하였다. 저용량 태양광 발전기가 저압에 연계되었을 경우 Inverter 제작기술의 발달로 전기품질에 큰 영향을 미치지는 않는 것으로 나타났으며 THD보다는 TDD가 분산전원 설치자 측면에서 좀더 여유를 제공함을 알 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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• pp.260-261
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• 2006

This paper describes a real time digital simulation method for the application of HTS tape to power devices. At present, in order to extend the power capacity of some area which has a serious problem of power quality, especially metropolitan complex city. there are so many problems such as ROW for cable line routes, space for downtown substations, and the environmental protection, etc. HTS technology is one of the best solutions. Simulation is required for safety before install of HTS power cable, a fabrication model used at the power system simulation. Here, in this paper, authors developed an algorithm connected with HTS by using Real-Time Digital Simulator(RTDS).