• Journal of the Korean Physical Society
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• 제73권12호
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• pp.1889-1894
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• 2018

An innovative small-scale piezoelectric energy harvester has been proposed to gather wind energy. A conventional horizontal-axis wind power generation has a low generating efficiency at low wind speed. To overcome this weakness, we designed a piezoelectric windmill optimized at low-speed wind. A piezoelectric device having high energy conversion efficiency is used in a small windmill. The maximum output power of the windmill was about 3.14 mW when wind speed was 1.94 m/s. Finally, the output power and the efficiency of the system were compared with a conventional wind power system. This work will be beneficial for the piezoelectric energy harvesting technology to be applied to the real world such as wireless sensor networks (WSN).

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 춘계학술발표대회 논문집
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• pp.277-280
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• 2009

Wind monitoring system is an absolutely-required system for assessing a performance and fatigue load of the wind energy generator in an on-shore wind energy experimental research complex. It was implemented for the purpose of monitoring the wind information measured from a meteorological tower at the monitoring house and of utilizing the measured data for the performance assessment, by using the LabVIEW program. Then, by adding the performance assessment-related data acquired from the wind energy generator during the performance assessment and the data recorder for synchronizing the data of meteorological tower, the system was implemented. Because it transmitted the data by converting the output 'RS-232' of data logger which measures the wind condition into CAN protocol, the data error rate was minimized, This paper is intended to explain the developed wind data monitoring system.

• 전기학회논문지
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• 제66권4호
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• pp.605-612
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• 2017

One of the biggest environmental issues that our world has been facing is climate change. In order to cope with such environmental issues, the world is putting a great deal of effort into energy conservation. The building sector, in particular, consumes 36% of the energy consumed worldwide and emits considerable amount of greenhouse gases. Therefore, introduction of renewable energies in the building sector is highly recommended. Renewable energy sources that can be utilized in the building sector include sunlight, solar heat, geothermal heat, fuel cells and wind power. The wind power generation system which converts wind energy into electrical energy has advantages in that wind is an unlimited and pollution-free resource. It is suitable to be connected to existing buildings because many years of operational experience and the enhanced stability of the system have made it possible to downsize the electrical generator. In case of existing buildings, it is necessary to consider the live loads of the buildings to connect the wind power generation system. This paper, through the connection of the wind power generation with existing buildings, promotes reduction of greenhouse gas emissions and energy independence by reducing energy consumption in the building sector. In order to connect the wind power generation system with an exciting building, the live load of the building and the area of the rooftop should be considered. The installable model is selected by comparing the live load of the building and the load of the wind power generation system. The maximum number of the wind turbines that can be installed is obtained by considering the separation distance between the wind turbines within the area of the rooftop. Installations are divided into single installations and multiple installations of two different types of wind turbines. After determining the maximum installable number, the optimal model that can achieve the maximum annual power generation will be selected by comparing the respective total annual amount of the power generation of different models.

• 한국지구과학회지
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• 제34권7호
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• pp.633-644
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• 2013

풍력 발전단지의 효율성 평가를 위하여 풍력-기상자원지도로부터 이론적 잠재량을 계산하고 행원 발전단지 발전량과 비교하였다. 풍력-기상자원지도는 기상청 국립기상연구소에서 개발된 1 km 해상도 자료를 이용하였다. 풍력-기상자원지도와 AWS(구좌) 풍속의 비교 검증 결과는 풍속이 과대 모의되었으며, 행원 발전단지 풍속의 일 변동성은 해륙풍의 영향으로 오후에 최대가 되는 일 변동 특성을 보였다. 풍력-기상자원지도로부터 산출된 발전량과 행원 발전단지 발전량의 비율은 24.8%이나, 발전량 빈도수 분포 형태는 유사하였다. 발전량 차이의 원인은 터빈의 기계적 오류, 풍력-기상자원지도 풍속의 과대 모의에 기인한 것으로 생각된다. 본 연구는 향후의 발전단지 효율성 증가를 위한 터빈의 재배치에 기여 할 것이다.

• 한국태양에너지학회 논문집
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• 제32권2호
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• pp.95-104
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• 2012

This study purposed to predict wind energy for small size wind power generators at 50m above the ground in each area using mean wind speed data for 10 minutes collected from 2001 to 2011 by meteorological data in large cities having over 60% of 15 story (50m) or higher apartments including Seoul, Daejeon, Gwangju and Daegu representing the inland region, and Busan, Incheon and Ulsan representing the coastal region. In the results of analysis, we confirmed close agree ment between observatory weather data and probability density distribution obtained using Weibull's parameters, and this suggests that Weibull's parameter is applicable to the estimation of wind energy. Hourly output energy using the mean wind speed for 10 minutes and output energy obtained from Weibull's parameter showed an error less than 5%, and thus it was found that wind energy can be evaluated using Weibull's modulus.

• 태양에너지
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• 제4권2호
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• pp.3-12
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• 1984

In this paper, how to design the wind power generation system is presented. It is shown that the wind system optimization can be achieved by consideration of the four factors; wind statistics, efficiency of conversion of wind energy to electrical energy, average annual energy extracted and load factor. The wind is characterized by a weibull probability function. The Weibull parameter is calculated for the characterizing wind and the primary design specification of ten different sites. Some graphs are presented, which can be used to design a wind system for maximum output of a specified load factor at given site. Two different systems, $V_c=0.4V_R$ and $V_c=0.5V_R$ are discussed, as samples, for investigation of the effects on the system through the variation of cut-in speed.

• 한국지진공학회논문집
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• 제21권6호
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• pp.295-301
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• 2017

This paper relates to the study of load characteristics applicable to wind turbine generators induced by earthquakes. An artificial design earthquake wave generated through the target spectrum and the envelope function of Richter Magnitude Scale (ML) 7.0 as in ASCE4-98 was created. A simulation of earthquake loads were performed according to the design load cases (DLC) 9.5~9.7 of GL guidelines. Additionally, simulation of seismic loads experienced by Wind Turbines installed in the Gyeongju region were carried out utilizing artificial earthquakes of ML 5.8 simulating the real earthquakes during the Gyeongju Earthquakes of Sept. 2016.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제14권4호
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• pp.305-312
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• 2014

This paper discusses real-time peak shaving algorithms for a large-scale battery energy storage system (BESS). Although several transmission and distribution functions could be implemented for diverse purposes in BESS applications, this paper focuses on a real-time peak shaving algorithm for an energy time shift, considering wind power generation. In a high wind penetration environment, the effective load levels obtained by subtracting the wind generation from the load time series at each long-term cycle time unit are needed for efficient peak shaving. However, errors can exist in the forecast load and wind generation levels, and the real-time peak shaving operation might require a method for wind generation that includes comparatively large forecasting errors. To effectively deal with the errors of wind generation forecasting, this paper proposes a real-time peak shaving algorithm for threshold value-based peak shaving that considers fuzzy wind power generation.

• 신재생에너지
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• 제7권1호
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• pp.8-14
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• 2011

As is the case in Korea, the expansion of renewable energy dissemination is an essential matter in Ukraine when considering its energy consumption and dependence on energy import. While Korea has set about promoting the new and renewable energy industry on the back of the national policy on green growth, Ukraine expects a virtuous circle of renewable energy industry with green tariffs and the attraction of foreign capital in association with carbon emission trade. Utilizing its well-developed heavy industrial sector including the shipbuilding and automobile industries, Korea expects wind turbine manufacturing to become one of its next-generation growth engines. Ukraine is also trying to enter the wind turbine system or parts manufacturing industry based on its automobile industry and advanced aerospace technology. Although the Crimean region in Ukraine seems to have excellent wind resources, and thus shows great potential as a location for wind farm development, political instability has been a major obstacle to the attraction of foreign capital, leading to delayed investment.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 추계학술대회 논문집
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• pp.290-294
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• 2008

Offshore wind farms will contribute significantly to the renewable generation of electricity for the world. The economic development of wind farms depends, however, on development of efficient solutions to a number of technical issues, one of these being the foundations for the offshore turbines. We review here the results of recent research for wind turbine foundations. Also it is a short overview of some of the challenges facing the growth of offshore wind energy foundation technology.