• Proceedings of the KIPE Conference
• /
• 2012.07a
• /
• pp.128-129
• /
• 2012

This paper proposed the wind turbine simulator for comparative study of the MPPT controls. The development of this wind turbine simulator is based on the torque controlled induction motor. The torque reference is obtained from a mathematical model of wind turbine whereas the inputs are rotor speed, wind speed and fixed-value of pitch angle. By using this wind turbine simulator, the real wind is not needed. Wind speed information can be stored and regenerated anytime. Hence it is possible to apply the same wind speed condition to different MPPT controls. With the same wind speed condition, it can fairly compare the advantages and disadvantages of the MPPT controls. The proposed wind turbine simulator is verified through PSIM simulation.

• 한국태양에너지학회:학술대회논문집
• /
• 2009.11a
• /
• pp.400-403
• /
• 2009

Current wind turbine units that are used primarily 3Blade type devices or large-scale wind-term capacity of 2MW of 60m~90m Blade diameter is applied. This is not the best suitable design with the designing condition for the special quality of wind condition in the South-West Coastal Areas of Korea where the wind speed frequency of average wind speed and over 10m/s high wind velocity is fairly low. For this matter, in this dissertation, the expecting generation amount of electric power is measured excluding a mechanical moment, considering wind power energy traveling to the Blade when 60m~120m blade is applied, based on 2MW wind generator. Also, we would like to propose the Blade diameter which is fitted by wind condition of South-West Coastal Areas of Korea.

• Atmosphere
• /
• v.16 no.3
• /
• pp.169-185
• /
• 2006

We have investigated the wind speed variations over the leeward region when the strong wind blows. In this study we employ Envi-met numerical model to simulate the effect of surface boundary conditions. This model is applied for three cases which are characterized by land use and terrain height. The base case having natural geographical condition shows the weakest wind speed around lee side of Chunsudae. The others which remove the vegetation and cut off the terrain above 20 m ASL represent the stronger wind speed than base case. The main factor of this result is the surface friction. The distinct variation of wind is found at offshore area between Chunsudae and the southern part of village, but the northern part where is apart from Chunsudae shows a small variation of wind pattern. The weakening of wind speed around residential area is a maximum of 4~10 m/s when the wind blows in the village as strong as 55 m/s. The gust wind speed is weakened about 7~17 m/s in this case if the coefficient of gust wind adapted as 1.75.

• Proceedings of the KSME Conference
• /
• 2001.06e
• /
• pp.361-366
• /
• 2001

The present study describes a practical estimation procedure about the pantograph under several severe aerodynamic load conditions. As the operating speed of the Korean Train Express(KTX) reaches 350km/h, structural safety at various conditions should be examined at the design stage. In the present study, a compact and reliable procedure is developed to get aerodynamic loads on each part of the pantograph regarding the typhoon condition, the train/tunnel interaction, the train/train interaction and the side wind condition. In the estimation procedure, 3-dimensional steady and unsteady CFD simulation around the high speed train facilitates assigning the external local flow condition around the pantograph. The procedure is verified using the results of the low speed wind tunnel test at JARI and applied to 7 flow conditions and 4 operation configurations.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.1178-1179
• /
• 2008

This paper describes a modeling of fixed speed wind power generation system which comprise of wind turbine, generator and grid. The wind turbine is based on MOD-2, which is IEEE standard wind turbine, and includes a component using wind turbine characteristic equation. Fixed speed induction generator is directly connected to grid, so the variation of wind speed has effects on the electrical torque and electrical output power. Therefore the power control mode pitch control system is necessary for aerodynamic control of the blades. But the power control mode does not operate at the fault condition. So it is required some methods to control the rotor speed at transient state for stabilization of wind power system. In this paper, simulation model of a fixed speed wind power generation system based on the PSCAD/EMTDC is presented and implemented under the real weather conditions. Also, a new pitch control system is proposed to stabilize the wind power system at the fault condition. The validity of the stabilization method is demonstrated with the results produced through sets of simulation.

• Journal of Korean Society for Atmospheric Environment
• /
• v.22 no.6
• /
• pp.888-903
• /
• 2006

This study analyze the change of wind pattern and intensity according to the transform of surface conditions, such as land use and height of terrain, over the leeward region. In order to do this, we have employed 'Envi-met' microscale atmospheric numerical model. When the same wind condition is considered, the wind speed of base case having natural surface condition of Chunsudae shows the weakest strength among different cases such as the 'bare case' and the '20 m case' which the plants is removed and the height of terrain is flatted as 20 m above the sea level over the Chunsudae, respectively. The weakening of wind speed is a maximum of $4{\sim}8 m/s$ when the inflow wind speed is 55 m/s.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.45 no.2
• /
• pp.185-192
• /
• 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 the Korean Society for Railway
• /
• v.10 no.3 s.40
• /
• pp.271-277
• /
• 2007

The Korean Tilting Train eXpress (TTX) development program is in progress for the purpose of running speed or passenger's comfort improvement at the curved track. However, the speed up and light weight of train make poor the dynamic safety of the TTX in strong cross wind. In this paper, 3-dimensional numerical analysis on the flow field around the TTX under strong cross wind is performed for each operating condition, such as the train speed, cross wind speed, tilting/nontilting condition, and so on. Due to the strong cross wind, the pressure distribution around the train becomes asymmetric, especially at the leading car. Asymmetrical pressure distribution causes the side force and strong unstability. The side force on the train is proportional to the train speed and cross wind speed. Based on the numerical results, the overturning coefficients are predicted for investigation of the train stability, and all of them are less than the critical value, 0.9. The results in this study would be a good data for providing importance to judgement of cross wind safety of TTX.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.26 no.7
• /
• pp.922-930
• /
• 2020

Marine accidents involving fishing boats, caused by a loss of stability, have been increasing over the last decade. One of the main reasons for these accidents is a sudden wind attacks. In this regard, the wind loads acting on the ship hull need to be estimated accurately for safety assessments of the motion and maneuverability of the ship. Therefore, this study aims to develop a computational model for the inlet boundary condition and to numerically estimate the wind load acting on a fishing boat. In particular, wind loads acting on a fishing boat at the wind speed profile boundary condition were compared with the numerical results obtained under uniform wind speed. The wind loads were estimated at intervals of 15° over the range of 0° to 180°, and i.e., a total of 13 cases. Furthermore, a numerical mesh model was developed based on the results of the mesh dependency test. The numerical analysis was performed using the RANS-based commercial solver STAR-CCM+ (ver. 13.06) with the k-ω turbulent model in the steady state. The wind loads for surge, sway, and heave motions were reduced by 39.5 %, 41.6 %, and 46.1 % and roll, pitch, and yaw motions were 48.2 %, 50.6 %, and 36.5 %, respectively, as compared with the values under uniform wind speed. It was confirmed that the developed inlet boundary condition describing the wind speed gradient with respect to height features higher accuracy than the boundary condition of uniform wind speed. The insights obtained in this study can be useful for the development of a numerical computation method for ships.

• 한국신재생에너지학회:학술대회논문집
• /
• 2011.11a
• /
• pp.33.2-33.2
• /
• 2011

The 'NREL Phase VI' model with a 10.06m diameter was tested in the NASA Ames tunnel to make a reference data of the computational models. The test was conducted at the one rotational speed, blade tip speed 38m/s and the Reynolds number of the sectional airfoils in that test was around 1E6. The 1/5 scale down model of the 'NREL Phase VI' model was used in this paper to study the power characteristics in low Reynolds number region, 0.1E6 ~ 0.4E6 which is achievable range for the conventional wind tunnel facilities. The torque generated by the blade was directly measured by using the torque sensor installed in the rotating axis for a given wind speed and rotational speed. The power characteristics below the stall condition, lambda > 4, was presented in this paper. The power coefficient is very low in the condition below the Re. 0.2E6 and rapidly increases as the Re. increases. And it still increases but the variation is not so big in the condition above the Re. 0.3E6. This results shows that to study the performance of the wind turbine blade by using the scaled down model, the Re. should be larger than the 0.3E6.