• 전력전자학회:학술대회논문집
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• 전력전자학회 2009년도 정기총회 및 추계학술대회 논문집
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• pp.287-289
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• 2009

This paper deals with a parallel processing uninterruptible power supply (UPS) for sudden voltage fluctuation in computer applications to integrate power quality improvement, load voltage stabilization and UPS. To reduce the complexity, cost and number of power conversions, which results in higher efficiency, only one voltage-controlled voltage source inverter (VCVSI) is used. The system provides sinusoidal voltage at the fundamental value of 220V/60Hz for the load during abnormal utility power conditions or grid failure. Also, the system can be operated to mitigate the harmonic current and voltage demand from nonlinear loads and provide voltage stabilization for loads when sudden voltage fluctuation occur, such as sag and swell. System operation simulation demonstrates that the system protects against outages caused by abnormal utility power conditions and sudden voltage fluctuations and changes.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.3-11
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• 2002

This paper presents the trend of low voltage and high current technology for DC-DC converters. It can be said that the output voltage of the on-board power supply has been rapidly moving forward a low voltage in proportion to the minuteness of the semiconductors. As for as its speed is concerned, the change of the market situation seems to be faster than that of R&D for the low voltage and high current products put out by power supply manufacturers. Here, the present situation and the trend of non-isolated type step-down DC-DC converter and isolated type DC-DC converter called "Brick" will be taken up mainly from the fellowing point of view. -low voltage and high current keeping up with the current demand for the latest telecommunication networks and broadband. -build-up of the total solution for dispersion system power supply. In this paper, an explanation is given to mainly concerning to the newest products in the supplier's position.

• 디지털융복합연구
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• 제15권7호
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• pp.41-53
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• 2017

본 연구에서는 2011년 3월 발생한 동일본대지진 이후 스마트그리드에 대한 관심이 높아지고 있는 가운데 일본의 스마트그리드 정책 추진현황 및 문제점에 초점을 맞춰 살펴보았다. 분석 결과, 일본에서는 2011년 동일본대지진으로 인한 전력수급 문제를 계기로 신재생에너지의 고정가격매수제도가 도입되고, 나아가 신재생에너지로 생산된 전력을 거래하는 분산형 그린 전력매매 시장을 설립하는 등 에너지 위기와 환경문제를 동시 해결하는 하나의 솔루션으로서 스마트그리드 관련 프로젝트가 본격적으로 실행되었다. 그 결과 피크전력 억제 및 CO2 삭감효과, 신재생에너지원을 이용한 에너지 수급의 안정적 확보 등 가시적인 성과를 거두었다. 한편, 현행 일본의 스마트그리드 정책 운영상의 개선과제로는 전력계통 안정화 장치의 도입(송배전망의 광역적 운용이나 대형 축전지 도입 등), 스마트그리드 관련 자국기술의 국제표준, 추진 스마트 그리드의 보안성 강화 지원 등을 제시하였다.

• Management Science and Financial Engineering
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• 제18권2호
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• pp.23-27
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• 2012

The problem of jointly determining a robust optimal bundle of price and order quantity for a retailer in a single-retailer, single supplier, single-product supply chain is considered. Demand is modeled as a decreasing power function of product price, and unit purchasing cost is modeled as a decreasing power function of order quantity and demand. Parameters defining the two power functions are uncertain but their possible values are characterized by ellipsoids. We extend a previous study in two ways; the purchasing cost function is generalized to take into account the economies of scale realized by higher product demand in addition to larger order quantity, and an exact transformation into an equivalent convex optimization program is developed instead of a geometric programming approximation scheme proposed in the previous study.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(2)
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• pp.760-763
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• 2004

The recent growth in the use of impactive and nonlinear loads, electronic, and medical devices sensitive to power quality has caused many power quality problems and power supply-and-demand problem. Recently, in power system not only the reliability of the power supply but also the DVR(Dynamic Voltage Restorer), UPS, and APF are being studied more and more. Hence, in this paper, Voltage sag detection algorithm for voltage sag corrector is proposed. Also, simple circuit for the experimental voltage sag is Introduced.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.498-500
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• 2012

According to the climatic characteristics of the wind power output is difficult to predict and a severe strain due to a change in output has been very influential in the grid. Jeju Hangwon wind farm, many of the wind generator is installed in a wide area because it is not have this device that artificially Smoothing is needed. In addition, By the requirements of the power company active power supply / control and improve power system reliability and energy storage during the peak demand for electricity using the energy stored in the power supply is needed. In this paper, Unit 12 in Jeju Hangwon demonstrated 0.5MW PCS and energy storage system associated with the wind through the stabilization of output and the leveling of output and test results will be introduced.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.301-303
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• 2005

This paper presents long-term shunt capacitor planning using optimal power flow. OPF allows the planning engineer to find feasible solution with minimal amount of engineering time. We used OPF for Shunt capacitor planning to get an optimal solution. The result of OPF is compared to the analysis by the conventional loadflow method and it is proved that OPF gives more cheaper and better planning solution. With the result, we analyzed the operational perspective for the reactive power supply and demand.

• 자원ㆍ환경경제연구
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• 제19권2호
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• pp.243-282
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• 2010

본 연구는 1991년~2007년간 우리나라 전력산업의 탄소배출에 미치는 요인들과 영향의 정도를 전력 수요측면과 공급측면으로 나누어 요인분해분석을 수행하였다. 전력수요측면에서는 전력사용의 효율성 향상이 배출 감소에 주된 영향을 미치는 반면, 전력을 소비하는 산업의 구조 변화는 오히려 배출을 증가시키는데 기여했음을 확인하였다. 공급측면에서는 탄소배출에 미치는 주요 요인으로 연료혼합, 화력발전효율, 발전구조의 변화 등이 있었으며 분석 결과 전력수요의 증가와 화력발전의 구조 변화가 탄소배출을 증가시키는 주요한 요인으로 작용한 반면 연료효율성은 향상되어 배출을 감소시키는 역할을 한 것으로 나타났다. 이로써 전력산업의 온실가스 감축을 위해 수요차원에서는 전력사용의 효율성을 향상시키고 공급차원에서는 화력발전을 대체하면서 발전 및 배출 효율성을 향상시킬 수 있는 정책이 마련되어야 한다는 것을 알 수 있었다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.940-947
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• 2011

Load capacity varies according to a day of the week in traction power supply system, because time schedule in railway is changed as demand for passengers and freights. Therefore, Voltage drop also varies as load capacity. In Korea railway, Voltage collected from catenary in train is decreased, as load supplied traction power supply system is increased. Therefore, investigation about voltage drop should be performed, before development of countermeasure against voltage drop. The investigation can be performed by simulation or field test. Naturally, field test is more precise than simulation. In addition, field test should be carried out at peak load. This paper presents test and analysis about voltage drop in railway. The test is performed in both a day of the week and weekend. The analysis is figured out comparison load capacity between two days and voltage drop across terminal.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.2210-2211
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• 2011

Load capacity varies according to a day of the week in traction power supply system, because time schedule in railway is changed as demand for passengers and freights. Therefore, Voltage drop also varies as load capacity. In Korea railway, Voltage collected from catenary in train is decreased, as load supplied traction power supply system is increased. Therefore, investigation about voltage drop should be performed, before development of countermeasure against voltage drop. The investigation can be performed by simulation or field test. Naturally, field test is more precise than simulation. In addition, field test should be carried out at peak load. This paper presents test and analysis about voltage drop in railway. The test is performed in both a day of the week and weekend. The analysis is figured out comparison load capacity between two days and voltage drop across terminal.