• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.386-389
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• 2006

The sea surface wind speed (SSWS) derived by microwave radiometer can be contaminated by change of microwave brightness temperature owing to the angle between the sensor azimuth and the wind direction (Relative Wind Direction). We attempt to correct the contamination to the SSWS derived by Advanced Microwave Scanning Radiometer (AMSR) on Advanced Earth Observing Satellite II (ADEOS-II), by applying the method proposed by Konda and Shibata (2004). The improvement of accuracy of the SSWS estimation amounts to roughly 60% of the error caused by the RWD effect.

• 신재생에너지
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• 제4권2호
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• pp.87-93
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• 2008

Wind tunnel test for the 12% scaled model of NREL Phase VI wind turbine was conducted in KARI low speed wind tunnel for $2006{\sim}2007$. The 1st and 2nd test was designed to find out the wind tunnel test method for the blade manufacturing accuracy and surface treatment method by using the composite and aluminum blades. And the 3rd test was designed to study the scale effect. The chord extension method which was used for Bo-105 40% scaled model was adapted for scale effect correction. Test results shows that the chord extension method works well for the torque slope but the maximum torque for scaled model is about 8% below than the real scale model. New correction method to correct this offset was proposed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.92-96
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• 2007

Microphone array beamforming method has been recognized as an important aeroacoustic research field and become a standard technique in localizing sound sources. This method also used in flight acoustic measurement, and especially, it is very useful when measure sounds inside the wind tunnel. In measuring sound which is inside the wind tunnel by traditional beamforming method, there are some errors caused by airstream. The speed and the propagation path of the sound changes as it travel through the airstream. This makes the error which the position of sound is changed a little bit to the down stream direction. In this paper, validation test has made about the correction equation for this wind effects of previous researches. And beamforming including shear layer correction was performed about a sound source in the anechoic open-jet windtunnel.

• 한국태양에너지학회 논문집
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• 제31권3호
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• pp.1-7
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• 2011

In the performance test for wind turbines of medium and large, The reference met-mast should be installed for measurement reference wind speed as IEC 61400-12-1 standards and design of booms for mounted an anemometer must be considered exactly. Boom-mounted cup anemometer are influenced by flow distortion of the mast and the boom. Therefore design of booms must be important so that flow distortion due to booms should be kept below 0.5%. But, in some cases at size of met-mast structure, the distance of boom from mast is longer then measurement of wind speed is impossible because of oscillation of boom-mounted anemometer. In this paper, We measured a wind speed at several point from mast and boom and we analyzed the error of wind speed at each point of measurement. Also, we will suggest a correction method using the data curve fitting about errors of wind speed between each point of mounted anemometer.

• 신재생에너지
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• 제9권1호
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• pp.12-16
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• 2013

The nacelle anemometer mounted behind the blade roots of a wind turbine measures distorted wind speed comparable with free-stream wind because of the wake effects caused dependent upon the operation of the wind turbine and the rotation of its blades. The field campaign was carried out to measure free-stream wind speed at a height identical to the height of the nacelle anemometer by deploying a ground-based remote-sensing equipment, LIDAR. It is derived that a third-order polynomial equation for correcting wind speed measured by the nacelle anemometer to undistorted free-stream wind speed incident to a wind turbine. It is anticipated that the derived correction equation enables wind speed measured by the nacelle anemometer to be used as a precise input for a wind turbine performance test and for developing an active control logic.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 추계학술대회 논문집
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• pp.278-281
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• 2008

In these days the installation of wind turbines or wind parks includes a high financial risk. So for the planning and the constructing of wind farms, long-term data of wind speed and wind direction is required. However, in most cases only few data are available at the designated places. Traditional Measure-Correlate-Predict (MCP) can extend this data by using data of nearby meteorological stations. But also Neural Networks can create such long-term predictions. The key issue of this paper is to demonstrate the possibility and the quality of predictions using Neural Networks. Thereto this paper compares the results of different MCP Models and Neural Networks for creating long-term data with various indexes.

• 대기
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• 제17권4호
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• pp.421-433
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• 2007

We have investigated the seasonal characteristics of surface turbulent fluxes observed at Ieodo Ocean Research Station from 2005 to 2006. Both 10Hz and 30 minutes flux data are quality controled, and tilt correction is performed in 10Hz data before quality control. The turbulent fluxes of open sea shows clear seasonal variations, though diurnal variations are barely shown. The seasonal ratio of stable and unstable conditions are closely related to the temperature difference between sea surface and air. In stable and semi-stable condition, latent and sensible heat fluxes have very small values without any relationship with wind speed. Though friction velocity shows slightly increasing trend with wind speed, it has many outliers. In unstable condition, turbulent fluxes increased with wind speed. Especially, latent heat flux increased rapidly during DJF. The latent heat flux at high wind speeds is more scatter.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
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• pp.375-378
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• 2003

This paper presents a study on the power factor improvement of the Wind turbine Generation System(WTGS) at Haeng-won wind farm in Jeju Island. Vestas WTGS named V47 as a model system is selected in this paper, and has 660 kW Power ratings. In this system, power factor correction is controlled by the conventional method with power condenor bank. So, model system at Haeng-won wind farm has very low power factor in the area of low wind speed, which is from 4 m/s to 6 m/s. This is caused by the power factor correction using power condenser bank To improve the power factor in the area of low wind speed, we used the static var compensator(SVC) using current controlled PWM power converter by IGBT switching device. finally, to verify the profosed method, the results of computer simulation using Psim program are presented to support the discussion.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.521-524
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• 2009

This study describes aerodynamic noise of high speed wind turbine system, which is invented as a new concept in order to reduce the torque of main shaft, for design parameters of the rotor blade. For parametric study of high speed rotor aerodynamic noise, Unsteady Vortex Lattice Method with Nonlinear Vortex Correction Method is used for analysis of wind turbine blade aerodynamic and Farassat1A and Semi-Empirical are used for low frequency noise and airfoil self noise. Parameters are chord length, twist and rotational speed for this parametric research. In the low frequency range, the change of noise is predicted the same level as each parameters varies. However, in case of broadband noise of blade, the change of rotational speed makes more variation of noise than other parameters. When the geometric angles of attack are fixed, as the rotational speed is increased by 5RPM, the noise level is increased by 4dB.

• 산업기술연구
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• 제25권B호
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• pp.157-164
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• 2005

Two methods, the bin averaging method and least square method, are often used in calibrating wind turbine test sites. The objective of this work was to determine a better method to predict the wind speed at wind turbine installing point. The calibration was done at the test site on a complex terrain located in Daegwallyeong, Korea. It was performed for two different cases based on the IEC 61400-12 power performance measurement standard. The wind speeds averaged for 10 minutes ranged between 4 m/s and 16 m/s. The wind-direction bins of each meteorological mast were 10 degrees apart, and only the bins having data measured for more than 24 hours were employed for the test site calibration. For both cases, the two methods were found to yield almost same results which estimated real wind speed very closely.