• 한국태양에너지학회 논문집
• /
• 제34권2호
• /
• pp.82-90
• /
• 2014

The MERRA reanalysis data provided online by NASA was applied to predict the annual energy productions of two largest wind farms in Korea. The two wind farms, Gangwon wind farm and Yeongyang wind farm, are located on complex terrain. For the prediction, a commercial CFD program, WindSim, was used. The annual energy productions of the two wind farms were obtained for three separate years of MERRA data from June 2007 to May 2012, and the results were compared with the measured values listed in the CDM reports of the two wind farms. As the result, the prediction errors of six comparisons were within 9 percent when the availabilities of the wind farms were assumed to be 100 percent. Although further investigations are necessary, the MERRA reanalysis data seem useful tentatively to predict adjacent wind resources when measurement data are not available.

• 한국해양공학회:학술대회논문집
• /
• 한국해양공학회 2000년도 추계학술대회 논문집
• /
• pp.79-83
• /
• 2000

A sliding mode fuzzy control (SMFC) with disturbance estimator is applied to design a controller for the third generation benchmark problem on an wind-excited building. A distinctive feature in vibration control of large civil infrastructure is the existence of large disturbances, such as wind, earthquake, and sea wave forces. Those disturbances govern the behavior of the structure, however, they cannot be precisely measured, especially for the case of wind-induced vibration control. Since the structural accelerations are measured only at a limited number of locations without the measurement of the wind forces, the structure of the conventional control may have the feed-back loop only. General structure of the SMFC is composed of a compensation part and a convergent part. The compensation part prevents the system diverge, and the convergent part makes the system converge to the sliding surface. The compensation part uses not only the structural response measurement but also the disturbance measurement, so the SMFC has a feed-back loop and a feed-forward loop. To realize the virtual feed-forward loop for the wind-induced vibration control, disturbance estimation filter is introduced. the structure of the filter is constructed based on an auto regressive model for the stochastic wind force. This filter estimates the wind force at each time instance based on the measured structural responses and the stochastic information of the wind force. For the verification of the proposed algorithm, a numerical simulation is carried out on the benchmark problem of a wind-excited building. The results indicate that the present control algorithm is very efficient for reducing the wind-induced vibration and that the performance indices improve as the filter for wind force estimation is employed.

• 한국항공우주학회지
• /
• 제37권11호
• /
• pp.1121-1130
• /
• 2009

QuikSCAT 위성의 관측자료를 이용하여 2000년 1월로부터 2008년 12월에 걸쳐 한반도 근해의 풍력자원을 평가 하였다. QuikSCAT 위성은 초단파 scatterometer를 이용하여 해수면 가까이의 풍향과 풍속을 전천후 상태에서 측정한다. 해면으로부터 10 m 높이에서 측정된 풍속을 power law모델을 이용하여 허브 높이에 맞게 외삽 보정하였다. 계산 결과 한반도의 남해와 동해에서 풍력에너지가 상대적으로 우세하다는 것을 알 수 있었다. 풍력 터빈 타워의 설치를 위해 깊은 수심을 피하고 대규모 풍력단지 조성을 위해 남해의 다도해 지역을 피한다면 한반도 서쪽 또는 남서쪽 연안이 대규모 풍력단지 조성에 유리하나 상대적으로 낮은 풍속을 고려한 블레이드 개발을 요한다. 바람 지도를 작성하였으며, 특정 지점에 대한 월별 풍속 변화를 파악하였다. 그리고 풍력에너지 밀도를 이용한 바람장미를 파악하였다.

• Wind and Structures
• /
• 제25권5호
• /
• pp.415-432
• /
• 2017

The nonlinear aerodynamic instability of a tensioned plane orthotropic membrane structure is theoretically investigated in this paper. The interaction governing equation of wind-structure coupling is established by the Von $K\acute{a}rm\acute{a}n's$ large amplitude theory and the D'Alembert's principle. The aerodynamic force is determined by the potential flow theory of fluid mechanics and the thin airfoil theory of aerodynamics. Then the interaction governing equation is transformed into a second order nonlinear differential equation with constant coefficients by the Bubnov-Galerkin method. The critical wind velocity is obtained by judging the stability of the second order nonlinear differential equation. From the analysis of examples, we can conclude that it's of great significance to consider the orthotropy and geometrical nonlinearity to prevent the aerodynamic instability of plane membrane structures; we should comprehensively consider the effects of various factors on the design of plane membrane structures; and the formula of critical wind velocity obtained in this paper provides a more accurate theoretical solution for the aerodynamic stability of the plane membrane structures than the previous studies.

• 동력기계공학회지
• /
• 제19권4호
• /
• pp.17-23
• /
• 2015

Because of the energy resources shortage and global pollution, the wind power systems have been developed consistently. Among the components of the wind power system, the rotor blades are the most important component. Generally it is made of GFRP material. Recently, GFRP material has been replaced by CFRP composite material in the blade which has an aerodynamic profile and twisted tip. However the failures has occurred in the trailing edge of the blade by the severe wind loading. Thus, tougher material than CFRP material is needed as like the aramid fiber. In this study, we investigated the mechanical behaviors of the blade using aramid fiber composites about wind speed variation. One-way FSI (fluid-structure interaction)analysis for the wind rotor blade was conducted. The structural analyses using the surface pressure loading resulted from wind flow field analysis were carried out. The results and analysis procedure in this paper can be utilized for the best strength design of the blade with aramid fiber composites.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2008년도 추계학술대회 논문집
• /
• pp.274-277
• /
• 2008

To evaluate high-resolution wind resources for local and coastal area with complex terrain was attemped to combine the prognostic MM5 mesoscale model with CALMET diagnostic modeling this study. Firstly, MM5 was simulated for 1km resolution, nested fine domain, with FDDA using QuikSCAT seawinds data was employed to improve initial meteorological fields. Wind field and other meteorological variables from MM5 with all vertical levels used as initial guess field for CALMET. And 5 surface and 1 radio sonde observation data is performed objective analysis whole domain cells. Initial and boundary condition are given by 3 hourly RDAPS data of KMA in prognostic MM5 simulation. Geophysical data was used high-resolution terrain elevation and land cover(30 seconds) data from USGS with MM5 simulation. On the other hand SRTM 90m resolution and EGIS 30m landuse was adopted for CALMET diagnostic simulation. The simulation was performed on whole year for 2007. Vertical wind field a hour from CALMET and latest results of MM5 simulation was comparison with wind profiler(KEOP-2007 campaign) data at HAENAM site.

• 드라이브 ㆍ 컨트롤
• /
• 제21권1호
• /
• pp.16-21
• /
• 2024

The yaw gearbox is a key device in a wind power generator that improves power generation efficiency by rotating hundreds of tons (400 to 600 tons) of nacelle so that the blade reaches 90 degrees in the wind direction. Recently, installation sites have been advancing from land to sea as they have become super-large at (8-12) MW to increase the economic feasibility of wind power generators and utilize excellent wind resources, and the target life of large wind power generators is 25 to 30 years. The yaw gearbox of 6 to 12 sets is installed in a very complex place inside the nacelle on the tower with parallels, and it is important to secure the reliability of the yaw gearbox because if a failure occurs after installation, it costs tens to hundreds of times the price of a new product to restore. In this study, equivalent loads were calculated by analyzing failure mode and field data, accelerated life test conditions were established, and a test device was constructed to perform the accelerated life tests and performance tests to ensure the reliability of the gearbox.

• 한국환경과학회지
• /
• 제19권8호
• /
• pp.983-999
• /
• 2010

Wind power energy is one of the favorable and fast growing renewable energies. It is most important for exact analysis of wind to evaluate and forecast the wind power energy. The purpose of this study is to improve the performance of numerical atmospheric model by data assimilation over a complex coastal area. The benefit of the profiler is its high temporal resolution and dense observation data at the lower troposphere. Three wind profiler sites used in this study are inhomogeneously situated near south-western coastal area of Korean Peninsula. The method of the data assimilation for using the profiler to the model simulation is the three-dimensional variational data assimilation (3DVAR). The experiment of two cases, with/without assimilation, were conducted for how to effect on model results with wind profiler data. It was found that the assimilated case shows the more reasonable results than the other case compared with vertical observation and surface Automatic Weather Station(AWS) data. Although the effect of sonde data was better than profiler at a higher altitude, the profiler data improves the model performance at lower atmosphere. Comparison with the results of 4 June and 5 June suggests that the efficiency with hourly assimilated profiler data is strongly influenced by synoptic conditions. The reduction rate of Normalized Mean Error(NME), mean bias normalized by averaged wind speed of observation, on 4 June was 28% which was larger than 13% of 5 June. In order to examine the difference in wind power energy, the wind power density(WPD) was calculated and compared.

• 한국유체기계학회 논문집
• /
• 제14권3호
• /
• pp.50-58
• /
• 2011

To utilize wind resources effectively around buildings in urban area, the magnitudes of wind velocity and turbulence intensity are important, which means the need of the information about the relationship between the magnitude of wind velocity and that of fluctuating wind velocity. In the paper, wind-tunnel experiments were performed to provide the information about Characteristic of Wind flow around buildings with the spanwise distance and the side ratio of buildings as variables. For a single building with the side ratios of one and two, the average velocity ratio was 1.4 and the velocity standard deviation ratio ranged from 1.4 to 2.6 at the height of 0.02m at the corner of the windward side, in which flow separation occurred. For twin buildings with the side ratios of one and two, the velocity ratio ranged from 2 to 2.5 as the spanwise distance varied at the height of 0.02m, and the velocity standard deviation ratio varied near 1.25. For twin buildings with the side ratios of one and two, the maximum velocity ratio was 1.75 at the height of 0.6m, and the maximum velocity standard deviation ratio was 2.1. It was also found from the results of CFD analysis and wind-tunnel experiments that for twin buildings with the side ratios of one and two, the difference between the velocity ratio of CFD analysis and that of wind-tunnel experiments at streamwise distances was near 0.75.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.349-353
• /
• 2001

Korea has a variety of favorable conditions for utilizing wind as energy. First of all, as a geographical characteristic, it is a peninsular country with its three frontiers surrounded by sea. Such a location makes the country influenced, all the year round, both by sea winds and by seasonal winds, so that it has a good possibility of putting its rich wind resources to use as an energy source. Particularly, in view of the results of observations and analysis of actual data about wind sources, it is quite possible to build wind paver plants in many regions across the country, such as inhabited islands dotted on its southern and western coasts around the Korean peninsular, a number of uninhabited islets attached the main islands, large-scaled reclaimed lands, and major inland areas. In Korea, the attempt to develop the technology of wind paver generation started in the 1970's. It was since 1988, when the Law on the promotion of Alternative Energy Development was enacted, that research and development activities for employing the wind force as a part of energy source have got into full swing. At that moment, however, due to the low level of domestic technological development, such efforts were mainly focused on the attainment of basic technologies with regard to wind power generation. Recently, there have been many noticeable changes in the international as well as domestic environments, such as the conclusion of the International Climate Treaty and the increase in public concerns of natural environment. It is quite possible to predict that the demand for wind paver generation will increase in the near future. Therefore, recognizing that wind, as a clean energy source, can be a promising method for coping with the International Climate Treaty and for replacing the fossil fuel, oil, this essay investigates the development history of wind paver generation systems and the status of technological development in Korea and presents an appropriate model for the development of the paver generation system that can compete with other energy sources.