• KIEAE Journal
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• 제12권1호
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• pp.127-132
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• 2012

The energy consumption in the world is growing rapidly. And the environmental issues of climate become a important task. The interest in renewable energy like wind and solar is increasing now. Especially, by reducing power transmission loss, a small wind power is getting attention at the residential areas and campus of university. In this study, we attempted to estimate and compare the wind energy density using wind data of AWS (Automatic Weather Station) of H University. In this case of a campus, the weibull distribution parameter C is 2.27, and K is 0.88. According to the data, the energy density of the small wind power is 12.7 W/m2. We did CFD(Computational Fluid Dynamics) simulations at H University campus by 7 wind directions(ENE, ESE, SE, NW, WNW, W, WSW). In the results, we suggest 4 small wind powers. The small wind power generating system can produce 4,514kWh annually.

• Journal of Power Electronics
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• 제13권5호
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• pp.737-745
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• 2013

Offshore wind farms are rapidly growing owing to their comparatively more stable wind conditions than onshore and land-based wind farms. The power capacity of offshore wind turbines has been increased to 5MW in order to capture a larger amount of wind energy, which results in an increase of each component's size. Furthermore, the weight of the marine turbine components installed in the nacelle directly influences the total mechanical design, as well as the operation and maintenance (O&M) costs. A reduction in the weight of the nacelle allows for cost-effective tower and foundation structures. On the other hand, longer transmission distances from an offshore wind turbine to the load leads to higher energy losses. In this regard, DC transmission is more useful than AC transmission in terms of efficiency because no reactive power is generated/consumed by DC transmission cables. This paper describes some of the challenges and difficulties faced in designing high-power-density power conversion systems (HPDPCSs) for offshore wind turbines. A new approach for high gain/high voltage systems is introduced using transformerless power conversion technologies. Finally, the proposed converter is evaluated in terms of step-up conversion ratio, device number, modulation, and costs.

• 한국지구과학회지
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• 제31권3호
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• pp.225-233
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• 2010

북한 지역의 27개 기상관측지점의 30년 바람 자료를 이용하여 고도 50 m에서의 풍력밀도를 분석하였다. 27개 지점의 연평균 풍력밀도는 58.6W/$m^2$로 1등급에 해당하는 풍력 자원이었다. 계절에 따른 평균 풍력밀도는 겨울보다 봄에 더 높았으며, 여름에는 봄의 50% 정도의 풍력밀도를 나타냈다. 풍력밀도의 일변화를 보면 거의 모든 관측 지점에서 오후에 비교적 높은 풍력밀도와 오전 3-6시 경에 낮은 풍력밀도를 보였으며, 일변화의 진폭은 봄에 가장 컸다. 특히 내륙 중심부인 개마고원 지역과 함경북도 동북부, 평안도 남부 해안, 황해도 해안 근처에서 비교적 높은 값을 나타냈다. 장진에서의 연평균 풍력밀도는 3등급인 151.2 W/$m^2$를 나타냈으며, 용연은 2등급인 102.4 W/$m^2$의 값을 보였다.

• 신재생에너지
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• 제7권3호
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• pp.83-91
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• 2011

The purpose of this study is to select appropriate location factors for wind power plant, provide detailed classification criteria, and find out appropriate sites for installing wind power plant in Gangwondo. In this study, the following 11 factors were extracted for site selection of wind power plant : wind resource, topography (valley angle, distance to the ridge), forest density, land use, preservation area, national park, Baekdu-Daegan, noise, shade, Transmission Line, and approaching roads. Each factor had relatively different level of importance so that AHP (Analytic Hierarchy Process) technique was used to calculated the weighted value per factor. For overlay analysis, classification criteria were prepared for each factor and each factor was classified into 3 grades : very appropriate, intermediate, poor. According to overlay analysis, the areas which received the highest grade (grade 5) was only in 0.16% of the total area of Gangwondo and had a tendency to exist along the mountain ridge over 600-meter elevation. Through analyzing the yearly average of wind power density, it was proved that the wind power density of areas with grade 4 or 5 had abundant wind resource over $400W/m^2$.

• 한국태양에너지학회 논문집
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• 제30권2호
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• pp.54-64
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• 2010

Interest in new and renewable energies like solar energy and wind energy is increasing throughout the world due to the rapidly expanding energy consumption and environmental reasons. An essential requirement for wind force power generation is estimating the size of wind energy accurately. Wind energy is estimated usually using meteorological data or field measurement. This study attempted to estimate wind energy density using meteorological data on daily mean wind speed and the Weibull parameters in Seoul, a representative inland city where over 60% of 15 story or higher apartments in Korea are situated, and Busan, Incheon, Ulsan and Jeju that are major coastal cities in Korea. According to the results of analysis, the monthly mean probability density distribution based on the daily mean wind speed agreed well with the monthly mean probability density distribution based on the Weibull parameters. This finding suggests that the Weibull parameters, which is highly applicable and convenient, can be utilized to estimate the wind energy density distribution of each area. Another finding was that wind energy density was higher in coastal cities Busan and Incheon than in inland city Seoul.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.501-504
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• 2009

In order to investigate of possibility for developing urban wind power, wind profile and wind power density are estimated using Sodar and Lidar based on surface. Since poor performance of Sodar and Lidar are often shown in a paticular meteorological condition, inter-comparison and validation with radio-sonde for each of instruments are performed. As a result, Lidar shows a good performance and wind data from Lidar are used to analyze wind profile and wind power density. It can be found that a wind power system mounted tall building in urban area is very attractive.

• 한국환경과학회지
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• 제20권7호
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• pp.839-843
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• 2011

We have established a wind map of Singapore, a city-state characterized its land cover by urban buildings to confirm a possibility of wind farm development. As a simple but useful approximation of urban canopy, a zero-plane displacement concept was employed. The territory is divided into 15 sectors having similar urban building layouts, and zero-plane displacement, equivalent roughness height at each sector was calculated to setup a terrain boundary condition. Annual mean wind speed and mean wind power density map were drawn by a CFD micrositing model, WindSim where Changi International Airport wind data was used as an in-situ measurement. Unfortunately, predicted wind power density does not exceed 80 $W/m^2$ at 50 m above ground level which would not sufficient for wind power generation. However, the established Singapore wind map is expected to be applied for wind environment assessment and urban planning purpose.

• 대기
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• 제28권1호
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• pp.1-13
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• 2018

Characteristics of wind resources of offshore and coastal regions were compared using wind data obtained from HeMOSU-1 (Herald of Meteorological and Oceanographic Special Unit-1) meteorological mast located at Southwestern Sea, and ground-based LiDAR (Light Detection And Ranging) at Gochang observation site near it. The analysis includes comparison of basic wind statistics such as mean wind speed, wind direction, power law exponent and their temporal variability as well as site assessment items for the wind power plant such as turbulence intensity and wind power density at the two observation sites. It was found that the wind at HeMOSU-1 site has lower diurnal and seasonal variability than that at Gochang site, which lead to smaller turbulence intensity. Overall, the results of the comparative analysis show that the wind resource at HeMOSU-1 site located offshore has more favorable condition for wind power generation than the wind resource at Gochang which shows nature of coastal area.

• 한국측량학회지
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• 제30권3호
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• pp.295-303
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• 2012

풍력발전 단지의 수익성 평가를 위해 연간 에너지 생산량(AEP ; Annual Energy Production)의 계산이 중요하다. AEP를 계산하기 위해서는 바람의 확률밀도함수(PDF ; Probability Density Function)와 풍력발전기의 발전곡선(PC; Power Curve)이 필요하며, AEP 예측의 정확성을 향상시키기 위해서는 허브 높이에서의 PDF예측과 그 높이의 공기밀도에 따른 풍력발전기 PC의 결정이 중요하다. 본 연구에서는 제주도 한동, 평대의 실관측 풍황탑(met mast) 자료를 이용하였으며 풍속의 PDF를 Weibull 분포 함수로 가정 하였고 Weibull 함수의 파라미터의 값이 높이에 따라 변화하는 양상을 확인하였다. Weibul 함수의 계산은 모멘트법과 LN-least법을 사용하였으며, 모멘트법과 LN-least법에 의한 형상계수의 경우 높이의 증가에 따라 변화를 보이지 않았고 평균값에서 ${\pm}0.1$의 변화 패턴을 보였다. 척도계수의 경우 높이가 증가함에 따라 선형적으로 증가하였으며 지형별 분류에 따른 높이별 척도계수의 기울기는 확연한 차이를 보이고 있었다. 60m 높이에서 관측된 바람의 상대도수와 관측 값의 높이 보정에 의한 공기밀도와 일반식에 의한 공기밀도를 각각 계산하여 그 결과에 대응하는PC를 선택하여 AEP차이를 계산하였다.

• 한국태양에너지학회 논문집
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• 제28권6호
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• pp.24-32
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• 2008

This paper discussed the Feasibility study of wind power generation considering the topographical characteristics of Korea. In order to estimate the exact generation of wind power plants, we analyzed and compared wind resources in mountain areas and plain areas by introducing not only wind speed, the most important variable, but also wind distribution and wind standard deviation that can reflect the influence of landform sufficiently. According to the results of this study, generation was almost the same at wind power plants installed in southwestern coastal areas where wind speed was low as at those installed in mountain areas in Gangwondo where wind speed was high. This demonstrates that the shape parameter of wind distribution is low due to the characteristics of mountain areas, and the standard deviation of wind speed is large due to the effect of mountain winds, therefore, actual generation compared to southwestern coastal areas is almost similar in mountain areas even though wind speed is high.