• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.374-377
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• 2007

This paper deals with a pitch control for reducing load of the wind turbine system. To make a model of the wind turbine system, the Momentum Theory and Blade Element Theory are used. Considering wind shear, wind model was also built. Due to a difference of the wind speed between upper parts and lower parts of the sweep area, overturning moment of the wind turbine is generated. So, in this paper through analyzing of the system model of the wind turbine, a control algorithm which was able to achieve both maintaining power and reducing overturning moment was proposed. Using matlab simulink, controller performance was verified.

• 한국전산유체공학회:학술대회논문집
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• 2006.10a
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• pp.155-158
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• 2006

In the present paper, the scale effects of two-dimensional airfoil and three-dimensional wind turbine were investigated by using FLUENT software. For two dimensional analysis, flow around S809 airfoil with various Reynolds No. and Mach No. conditions were simulated. For three dimensional analysis, scaled NREL Phase VI wind turbine models from 6% to 1,600% were simulated under the same tip speed ratio condition. Finally, aerodynamic comparisons between two-dimensional flow and three dimensional wind turbine flow are made for the feasibility study of scale effect corrections. Currently, KARI(Korea Aerospace Research Institute) is preparing for the wind tunnel test of 12% NREL Phase VI wind turbine and the performance analysis of the scaled NREL wind turbine model will be validated by the wind tunnel test.

• New & Renewable Energy
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• v.6 no.3
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• pp.39-46
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• 2010

With growing of wind turbine industry, offshore wind energy is getting more attention in recent years. Among all the components of offshore wind turbines, the foundation of the offshore wind turbine plays a key role in stability of whole system. In this work, the 5 MW NREL reference wind turbine with rated speed of 11.4 m/s is used for load calculation. Wind and wave loads are calculated using GH-Bladed (Garard Hassan) and FAST (NREL). Additionally, FE simulation is carried out to investigate the wave effect on the support structure. Meanwhile, this work is to simulate systemic and optimized load cases for the foundation analysis of wind turbine system.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.2
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• pp.185-192
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• 1996

This paper presents a design of vertical axis Darrieus wind turbine combine with Savonius for wind-power generating system to be adapted for variable wind speed. The wind turbine consists of two troposkien- and four Savonius-blades. Darrieus turbine is designed with diameter 9.4[m], chord length 380[mm], tip speed ratio 5. Savonius turbine is designed with diameter 1.8[m], height 2[m], tip speed ratio 0.95. The design of turbine is laid for the main data of rated wind speed 10[m/s], turbine speed 101.4[rpm]. The generating power is estimated to maximum power 20[kW], and this is converted to commercial power line by means of three phase synchronous generator-inverter system. Generating system is designed for operation on VSVF(variable speed variable frequency) condition and constant voltage system.

• Journal of Ocean Engineering and Technology
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• v.35 no.5
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• pp.347-359
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• 2021

This study aims to evaluate the dynamic responses of the jacket-type offshore wind turbine using FAST software (Fatigue, Aerodynamics, Structures, and Turbulence). A systematic series of simulation cases of a 5 MW jacket-type offshore wind turbine, including wind-only, wave-only, wind & wave load cases are conducted. The dynamic responses of the wind turbine structure are obtained, including the structure displacement, rotor speed, thrust force, nacelle acceleration, bending moment at the tower bottom, and shear force on the jacket leg. The calculated time-domain results are transformed to frequency domain results using FFT and the environmental load with more impact on each dynamic response is identified. It is confirmed that the dynamic displacements of the wind turbine are dominant in the wave frequency under the incident wave alone condition, and the rotor thrust, nacelle acceleration, and bending moment at the bottom of the tower exhibit high responses in the natural frequency band of the wind turbine. In the wind only condition, all responses except the vertical displacement of the wind turbine are dominant at three times the rotor rotation frequency (considering the number of blades) generated by the wind. In a combined external force with wind and waves, it was observed that the horizontal displacement is dominant by the wind load. Additionally, the bending moment on the tower base is highly affected by the wind. The shear force of the jacket leg is basically influenced by the wave loads, but it can be affected by both the wind and wave loads especially under the turbulent wind and irregular wave conditions.

• Journal of Hydrogen and New Energy
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• v.24 no.6
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• pp.558-565
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• 2013

This paper presents how to determine AEP(Annual Energy Production) by a small wind turbine in DuckjeokDo island. Evaluation of AEP is introduced to make a self-contained island including renewable energy sources of wind, solar, and tidal energy. To determine the AEP in DuckjeokDo island, a local wind data is analyzed using the annual wind data from Korea Institute of Energy Research firstly. After the wind data is separated in 12-direction, a mean wind speed at each direction is determined. And then, a small wind turbine power curve is selected by introducing the capacity of a small wind turbine and the energy production of the wind turbine according to each wind direction. Finally, total annual wind energy production for each small wind turbine can be evaluated using the local wind density and local energy production considering a mechanical energy loss. Throughout the analytic study, it is found that the AEP of DuckjeokDo island is about 2.02MWh/y and 3.47MWh/y per a 1kW small wind turbine installed at the altitude of 10 m and 21m, respectively.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.286-289
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• 2008

Wind turbine industry is booming and spending a lot on research for improving the performance of its present machines and increasing their capacity. Wind turbine requires service life of about 20 years and each components of wind turbine requires high durability, because installation and maintenance costs are more expensive than generated electricity by wind-turbine. So the design of wind turbine must be verified in various condition before production step. For this work, high reliability model for analysis is required. Drivetrain model is modeled by multibody dynamic modeling method. The model constituted with rotor blades, hub, main shaft, gear box, high speed shaft and generator. Natural frequency and torsional stiffness of drivetrain are calculated and analyzed.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.512-515
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• 2009

This research describes on airfoil shape design, crucial to core technique and algorithm optimization for the wind turbine blade development. We grasped the parameter to define the airfoil shape in the wind turbine blade and aircraft, and the important performance characteristic of the airfoil. The airfoil shape function is selected by studying which is suitable for wind turbine blade airfoil development. The selected method is verified by to compare the generated airfoil shape with base airfoil. The new airfoils were created by the selecting shape function based on the well-known airfoil for wind turbine blades. In addition, we performed aerodynamic analysis about the generated airfoils by XFOIL and estimated the point of difference in the airfoil shape parameter using the aerodynamic performance results which is compared with basic airfoil. This result data applies to the fundamental research for a wind turbine blade optimization design and accomplished the aerodynamic analysis manual.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.8
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• pp.877-884
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• 2006

The objective of this study is to investigate the aerodynamic characteristics of a vertical axis wind turbine blade as the basic study of a design of a vertical axis wind turbine. The lift and drag coefficients of the various shape of the vortical axis wind turbine blades are analyzed and compared using the CFD code Fluent. To validate the numerical analysis, the predicted results of the Fluent are compared with those of the Xfoil code and the experimental results. We conclude that the program Fluent can be used to predict the aerodynamics of the wind turbine blade. By comparing the predicted results of the aerodynamic characteristics of the different shape of the blades, an appropriate shape of the blade is suggested to design the vortical axis wind turbine blade.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.5
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• pp.326-333
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• 2009

Design life-time of a wind turbine is required to be at least 20 years. In the meantime, the wind turbine will experience a lot of load cases such as extreme loads and fatigue loads which will include several typhoons per year and extreme gusts with 50 years recurrence period as well as endless turbulence flow. Therefore, IEC61400-1 specifies design load cases to be considered in the wind turbine design and requires the wind turbine to withstand the load cases in various operational situations. This paper investigates the ultimate loads which the wind turbine will experience for 20 years and their characteristics based on the IEC61400-1 using an aero-elastic software, GH-Bladed. And the performance characteristics of a wind turbine such as electrical power generation and annual energy yield are also investigated.