• Journal of Electrical Engineering and Technology
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• 제12권5호
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• pp.1719-1728
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• 2017

Recent concerns about environmental conditions have triggered the growing interest in using green energy resources. These sources of energy, however, bring new challenges mainly due to their uncertainty and intermittency. In order to alleviate the concerns on the penetration of intermittent energy resources, this paper investigates impacts of realizing demand-side potentials. Among different demand-side management programs, this paper considers demand response wherein consumers change their consumption pattern in response to changing prices. The research studies demand response potentials from different load sectors on generation system well-being. Consumers' sensitivity to time-varying prices is captured via self and cross elasticity coefficients. In the calculation of well-being indices, sequential Monte Carlo simulation approach is accompanied with fuzzy logic. Finally, IEEE-RTS is used as the test bed to conduct several simulations and the associated results are thoroughly discussed.

• Journal of Electrical Engineering and Technology
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• 제1권4호
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• pp.414-422
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• 2006

Deterministic techniques have been applied in power system planning for many years and there is a growing interest in combining these techniques with probabilistic considerations to assess the increased system stress due to the restructured electricity environment. The overall reliability framework proposed in this paper incorporates the deterministic N-1 criterion in a probabilistic framework, and results in the joint inclusion of both adequacy and security considerations in system planning. The combined framework is achieved using system well-being analysis and traditional adequacy assessment. System well-being analysis is used to quantify the degree of N-1 security and N-1 insecurity in terms of probabilities and frequencies. Traditional adequacy assessment is Incorporated to quantify the magnitude of the severity and consequences associated with system failure. The concepts are illustrated by application to two test systems. The results based on the overall reliability analysis framework indicate that adequacy indices are adversely affected by a generation deficient environment and security indices are adversely affected by a transmission deficient environment. The combined adequacy and security framework presented in this paper can assist system planners to realize the overall benefits associated with system modifications based on the degree of adequacy and security, and therefore facilitate the decision making process.

• 조명전기설비학회논문지
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• 제28권12호
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• pp.38-44
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• 2014

The photovoltaic power system is performing power generation by being installed in outdoors. Therefore it has the characteristics affected by environmental factors. In particular, if the solar power generation facility connected to the grid, the power can be generated continuously in a state of being secured operating voltage of the inverter and solar irradiation. In that case, if an abnormal situation such as flooding or heavy rains has occur, the possibility of electric shock or damage of facilities due to current leakage or a floating matters is present. In this paper, we performed electrical safety assessment about the connection part, junction box and cable of the solar module when the solar power system was flooded. we also assessed whether or not the leakage current is occurred in case of the cable was damaged. As a result, in case of the leakage current is large, we can be known that it is the risk of electric shock as well as cause of inverter damage.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.855-861
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• 2008

The development of fuel cell hybrid power system, as a next generation power system for solving the global warming, has been being made actively progress around passenger vehicles. Also, in case of railway vehicles in unelectrified railway line, the adoption of fuel cell hybrid power system is being studied around well-known manufacturers. This paper introduces both the configuration and the control strategy of fuel cell hybrid power system in order to apply to a light electronic railway vehicle having a repeated driving pattern of acceleration, coasting and deceleration and provides simulation results to evaluate their validity.

• 신재생에너지
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• 제9권2호
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• pp.51-57
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• 2013

The Grid code is being strengthen as increase of renewable energy ratio. Especially, the grid connection regulations are continuously being updated for stable operation of power grids. Static grid support and Dynamic grid support must make an accurate measure at Grid connected point because they needs control algorithm individually. It has to exactly measure voltage including switching ripple at the output of the inverter generating system. In addition, it is necessary to have an accurate voltage measurement when the situation rapidly changing the grid impedance is caused by the input of serial impedance of transformer and line impedance as well as Grid Fault Device. In this paper, We propose a new detection method of grid voltage to calculate accurately the r.m.s voltage of the grid connection point along the standard required by the low voltage regulation. We verified performance through simulation grid fault device.

• 대한공간정보학회지
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• 제17권2호
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• pp.133-143
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• 2009

차세대 수치지도 수시갱신 시스템은 효율적인 수시갱신 체계를 구축하고 데이터의 최신성을 유지하며 고품질의 서비스와 효율적 관리를 수행하기 위한 시스템으로 기존 도엽단위의 수치지도 뿐만 아니라 객체 기반 연속 수치지도의 수시갱신이 가능하도록 시스템이 설계되었으며, 이에 따라 개발이 이루어지고 있다. 본 연구에서는 차세대 수치지도 수시갱신 시스템의 활용 방안 제시 및 경쟁력 확보에 기여하고자 차세대 수치지도 수시갱신 시스템에 대하여 객체기반의 연속 수치지도 및 도엽단위 수치지도의 갱신 실험을 수행하여 시스템 운영에 따른 문제점과 개선사항을 제시하였다. 또한 국토지리정보원을 대상으로 시스템 도입에 따른 비용 및 편익에 대한 분석을 수행하여 차세대 수치지도 수시갱신 시스템의 경제성에 대한 분석을 수행하였다.

• International Journal of Precision Engineering and Manufacturing-Green Technology
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• 제5권5호
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• pp.623-630
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• 2018

The renewable energy systems have been in the spotlight as an alternative for environmental issues. Therefore, the governmental policies are being implemented to spread of promote power generation system using renewable energy in various countries around the world. In addition, Korea has also developed a policy called the power trading contract which can profit from electricity produced from renewable power generation system through Korea Electric Power Corporation (KEPCO) and Korea Power Exchange (KPX). As a result, the power trading contracts can trade power after self-consuming in-house by using small-scale renewable power system for residential customers as well as electricity retailers. The power trading contracts applicable as a small-scale power system have a 'Net metering (NM)' and a 'Power Purchase Agreement (PPA)', and these two types of power trading contracts trade surplus power, but payment method of each power trading is different. The microgrid proposed in this paper is based on grid connected microgrid using Photovoltaic (PV) system and Energy Storage System (ESS), that supplied power to residential demand, we evaluate the operation cost of microgrid by power demand in each power trading contracts and propose the appropriate power trading contracts according to electricity demand.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.405-408
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• 2004

The sheet parts are formed with dies conventionally. But this conventional forming process is not suited to small volume and varied production for the reason of high cost. For the solution of this problem, a new forming process, which is called CNC incremental sheet forming, is being introduced. This process can form sheet parts without die, and is very well suited to small volume and varied production in space flight and automobile. In this paper, dieless CNC forming system based on a machining center is developed. A special device to grasp and pull the blank sheet built in the machining center and tool path generation S/W from STL file of 3-D model are developed. Several sheet parts are incrementally formed to verify the effectiveness of the developed system.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 추계학술대회논문집
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• pp.184-187
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• 2004

The sheet parts are formed with dies conventionally. But this conventional forming process is not suited to small volume and varied production for the reason of high cost. For the solution of this problem, a new forming process, which is called CNC incremental sheet forming, is being introduced. This process can form sheet parts without die, and is very well suited to small volume and varied production in space flight and automobile. In this paper, dieless CNC forming system based on a machining center is developed. A special device to grasp and pull the blank sheet built in the machining center and tool path generation S/W from STL file of 3-D model are developed. Several sheet parts are incrementally formed to verify the effectiveness of the developed system.

• 한국농공학회논문집
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• 제50권6호
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• pp.37-47
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• 2008

Photovoltaic power generation is currently being recognized as one of the most popular sources for renewable resources over the country. Although it is also being adapted to rural area for may reasons, it is important to estimate the magnitudes of power outputs with reliable statistical methodologies, while applying historical daily solar energy data, for correct feasibility analysis. In this study, one of the well-known statistical methodologies is employed to define the appropriate probability distributions for monthly power outputs for the selected rural area, county of Seo-san, province of Chungnam. The results imply that the assumption of normal distributions for several months may lead to incorrect decision-making and therefore lead to the unreliable feasibility analysis. Generalized beta and triangular distributions were found to be superior to normal distribution, when describing monthly probability distributions for daily photovoltaic power. Based on the appropriate distributions resulted from this study, Monte Carlo simulation technique was also applied to provide additional flexible information for the relevant decision makers. This study found out new finding that the probability distributions should be considered to make planning of the photovoltaic power system in rural village unit, in order to give reasonable economic analysis to the decision makers.