scholarly journals Time-Domain Modeling of Tower Shadow and Wind Shear in Wind Turbines

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Swagata Das ◽  
Neeraj Karnik ◽  
Surya Santoso
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Time Domain ◽  
Wind Shear ◽  
Electrical Power ◽  
Rotational Frequency ◽  
Domain Modeling ◽  
Periodic Fluctuations ◽  
Electrical Power Output ◽  
Tower Shadow

Tower shadow and wind shear contribute to periodic fluctuations in electrical power output of a wind turbine generator. The frequency of the periodic fluctuations is times the blade rotational frequency , where is the number of blades. For three-bladed wind turbines, this inherent characteristic is known as the effect. In a weak-power system, it results in voltage fluctuation or flicker at the point of common coupling of the wind turbine to the grid. The phenomenon is important to model so as to evaluate the flicker magnitude at the design level. Hence, the paper aims to develop a detailed time-domain upwind fixed speed wind turbine model which includes the turbine's aerodynamic, mechanical, electrical, as well as tower shadow and wind shear components. The model allows users to input factors such as terrain, tower height, and tower diameter to calculate the oscillations. The model can be expanded to suit studies involving variable speed wind turbines. Six case studies demonstrate how the model can be used for studying wind turbine interconnection and voltage flicker analysis. Results indicate that the model performs as expected.

scholarly journals Dynamic Modeling of Wind Turbines Based on Estimated Wind Speed under Turbulent Conditions

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1907 ◽  
Author(s):  
Ahmed G. Abo-Khalil ◽  
Saeed Alyami ◽  
Khairy Sayed ◽  
Ayman Alhejji
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Shear ◽  
Large Scale ◽  
Estimation Error ◽  
Turbine Rotor ◽  
Average Wind Speed ◽  
Rotating Speed ◽  
Tower Shadow

Large-scale wind turbines with a large blade radius rotates under fluctuating conditions depending on the blade position. The wind speed is maximum in the highest point when the blade in the upward position and minimum in the lowest point when the blade in the downward position. The spatial distribution of wind speed, which is known as the wind shear, leads to periodic fluctuations in the turbine rotor, which causes fluctuations in the generator output voltage and power. In addition, the turbine torque is affected by other factors such as tower shadow and turbine inertia. The space between the blade and tower, the tower diameter, and the blade diameter are very critical design factors that should be considered to reduce the output power fluctuations of a wind turbine generator. To model realistic characteristics while considering the critical factors of a wind turbine system, a wind turbine model is implemented using a squirrel-cage induction motor. Since the wind speed is the most important factor in modeling the aerodynamics of wind turbine, an accurate measurement or estimation is essential to have a valid model. This paper estimates the average wind speed, instead of measuring, from the generator power and rotating speed and models the turbine’s aerodynamics, including tower shadow and wind shear components, without having to measure the wind speed at any height. The proposed algorithm overcomes the errors of measuring wind speed in single or multiple locations by estimating the wind speed with estimation error less than 2%.

scholarly journals Mitigation of Flickering in DFIG Based Wind Turbines using Individual Pitch Control

2019 ◽  
Vol 8 (11S2) ◽  
pp. 71-78
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Shear ◽  
Control Method ◽  
Matlab Simulink ◽  
Pitch Control ◽  
Set Up ◽  
Individual Pitch Control ◽  
Tower Shadow

due to the breeze beat boom, wind shear and tower shadow affects, community related breeze generators are the wellsprings of power modifications which additionally can also supply shimmer over the span of regular development. This paper proposes a model of a MW-set up variable-pace wind turbine with a doubly continued confirmation generator to research the blaze transmission and equalization problems. To facilitate the flashes we were the usage of a man or female make commitments manage contraption the earlier days. on this paper, a moved pitch territory control method relying on the smooth cause is proposed for the variable-rhythm wind turbine systems, in which the generator pace slip-up and exchange speed blunder are utilized as manage enter elements for the cushy cause controller (FLC). The pitch vicinity reference is made through manner of the use of the FLC, that could capture up at the nonlinear regular for the pitch element to the breeze pace. This paper offers head alternate of wind energy, wind turbine linearization and dynamic displaying are settled. The feathery reason controller is carried out for trade draining edge of wind turbine and customary energy might be collect. The square represent of proposed pitch oversee which consolidates pitch controller, actuator version and turbine linearized displayed with the nice valuable asset of the usage of Matlab/Simulink programming.

scholarly journals Power Performance Measurements of the NREL CART-2 Wind Turbine Using a Nacelle-Based Lidar Scanner

2014 ◽  
Vol 31 (10) ◽  
pp. 2029-2034 ◽  
Author(s):  
Andreas Rettenmeier ◽  
David Schlipf ◽  
Ines Würth ◽  
Po Wen Cheng
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Shear ◽  
Electrical Power ◽  
Performance Testing ◽  
Performance Measurements ◽  
Power Performance ◽  
Lidar System ◽  
Scanning Lidar ◽  
Electrical Power Output

Abstract Different certification procedures in wind energy, such as power performance testing or load estimation, require measurements of the wind speed, which is set in relation to the electrical power output or the turbine loading. The wind shear affects the behavior of the turbine as hub heights and rotor diameters of modern wind turbines increase. Different measurement methods have been developed to take the wind shear into account. In this paper an approach is presented where the wind speed is measured from the nacelle of a wind turbine using a scanning lidar system. The measurement campaign was performed on the two-bladed Controls Advanced Research Turbine (CART-2) at the National Wind Technology Center in Colorado. The wind speed of the turbine inflow was measured and recalculated in three different ways: using an anemometer installed on a meteorological mast, using the nacelle-based lidar scanner, and using the wind turbine itself. Here, the wind speed was recalculated from turbine data using the wind turbine as a big horizontal anemometer. Despite the small number of useful data, the correlation between this so-called rotor effective wind speed and the wind speed measured by the scanning nacelle-based lidar is high. It could be demonstrated that a nacelle-based scanning lidar system provides accurate measurements of the wind speed converted by a wind turbine. This is a first step, and it provides evidence to support further investigations using a much more extensive dataset and refines the parameters in the measurement process.

Coupled Dynamic Analysis for Multi-Unit Floating Offshore Wind Turbine in Maximum Operational and Survival Conditions

2015 ◽  
Author(s):  
H. K. Jang ◽  
H. C. Kim ◽  
M. H. Kim ◽  
K. H. Kim
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Time Domain ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Random Waves ◽  
Mooring Lines ◽  
Floating Offshore Wind Turbine ◽  
Coupled Dynamic Analysis ◽  
Floating Offshore Wind Turbines

Numerical tools for a single floating offshore wind turbine (FOWT) have been developed by a number of researchers, while the investigation of multi-unit floating offshore wind turbines (MUFOWT) has rarely been performed. Recently, a numerical simulator was developed by TAMU to analyze the coupled dynamics of MUFOWT including multi-rotor-floater-mooring coupled effects. In the present study, the behavior of MUFOWT in time domain is described through the comparison of two load cases in maximum operational and survival conditions. A semi-submersible floater with four 2MW wind turbines, moored by eight mooring lines is selected as an example. The combination of irregular random waves, steady currents and dynamic turbulent winds are applied as environmental loads. As a result, the global motion and kinetic responses of the system are assessed in time domain. Kane’s dynamic theory is employed to formulate the global coupled dynamic equation of the whole system. The coupling terms are carefully considered to address the interactions among multiple turbines. This newly developed tool will be helpful in the future to evaluate the performance of MUFOWT under diverse environmental scenarios. In the present study, the aerodynamic interactions among multiple turbines including wake/array effect are not considered due to the complexity and uncertainty.

Dynamic Optimization of Drivetrain Gear Ratio to Maximize Wind Turbine Power Generation—Part 2: Control Design

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
John F. Hall ◽  
Dongmei Chen
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Electrical Power ◽  
Control Design ◽  
Gear Ratio ◽  
Small Wind Turbines ◽  
Full Load Operation ◽  
Wind Profiles ◽  
Turbine Model

The cost of electrical power produced by small wind turbines impedes the use of this technology, which can otherwise provide power to millions of homes in rural regions worldwide. To encourage their use, small wind turbines must capture wind energy more effectively while avoiding increased equipment costs. A variable ratio gearbox (VRG) can provide this capability to the simple fixed-speed wind turbine through discrete operating speeds. This is the second of a two-part publication that focuses on the control of a VRG-enabled wind turbine. The first part presented a 100 kW fixed speed, wind turbine model, and a method for manipulating the VRG and mechanical brake to achieve full load operation. In this study, an optimal control algorithm is developed to maximize the power production in light of the limited brake pad life. Recorded wind data are used to develop a customized control design that is specific to a given site. Three decision-making modules interact with the wind turbine model developed in Part 1 to create possible VRG gear ratio (GR) combinations. Dynamic programming is applied to select the optimal combination and establish the operating protocol. The technique is performed on 20 different wind profiles. The results suggest an increase in wind energy production of nearly 10%.

scholarly journals Relationship between Starting Torque and Thermal Behaviour for a Permanent Magnet Synchronous Generator (PMSG) Applied with Vertical Axis Wind Turbine (VAWT)

2021 ◽  
Vol 13 (16) ◽  
pp. 9151
Author(s):  
Mintra Trongtorkarn ◽  
Thanansak Theppaya ◽  
Kuaanan Techato ◽  
Montri Luengchavanon ◽  
Chainuson Kasagepongsarn
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Permanent Magnet ◽  
Wind Turbines ◽  
High Speed ◽  
Electrical Power ◽  
Vertical Axis ◽  
Vertical Axis Wind Turbine ◽  
Minimization Method ◽  
Starting Torque

The application of wind turbine technology in low wind speed regions such as Southeast Asia has recently attracted increased attention. Wind turbines are designed as special structures with low starting torque, and many starting torque minimization processes exist for permanent magnet synchronous generators (PMSGs). Plurality is applied to decrease the starting torque in radial flux permanent magnet disk generators. The most popular starting torque minimization method uses a magnet skew technique. When used at 20°, this technique reduced starting torque by 4.72% (on load) under 500 rpm at 50 Hz for 120 min. By contrast, a PMSG with magnet skew conditions set at under 2° reduced electrical power by 3.86%. For high-speed PMSGs, magnet skew techniques affect the generation of heat in the coils (stator), with heat decrease at the middle of the coil, on its surface and between the coils at 2.90%, 3.10% and 2.40%, respectively. PMSGs were installed in vertical axis wind turbines (VAWTs), and heat generation in relation to wind speed and electrical power was assessed. Magnet skew techniques can be used in PMSGs to reduce staring torque, while skew techniques also reduce electrical power and heat generated at the stator.

scholarly journals Oscillation analysis of doubly-fed unit considering wind speed variation

2021 ◽  
Vol 2087 (1) ◽  
pp. 012035
Author(s):  
Ke Wan
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Shear ◽  
Mechanical Transmission ◽  
Power Fluctuation ◽  
Shadow Effect ◽  
Oscillation Analysis ◽  
Shear Component ◽  
Doubly Fed ◽  
Tower Shadow

Abstract Tower shadow effect and wind shear may cause power oscillation of the unit. In order to study the influence of tower shadow effect and wind shear on the output power of wind turbine, a doubly-fed turbine was taken as an example. Firstly, the influence of tower shadow effect and wind shear was considered to study the periodic power fluctuation characteristics of wind turbines. Then, according to the dynamic model of mechanical transmission mechanism, the influences of the inertia constants of generator, fan and the stiffness coefficient of the shaft system on the transient performance of the wind power generation system were considered respectively. Finally, a single machine infinite bus system model including wind speed model is built on PSCAD/EMTDC platform for simulation. The results show that the tower shadow effect and wind shear component can cause the power fluctuation of the turbine. When the power fluctuation frequency of the turbine is equal to the natural oscillation frequency of the wind turbine shafting, the resonance of the turbine occurs, and the amplitude of oscillation is the largest. Changing the transmission parameters will affect the power fluctuation amplitude and speed response speed of the unit.

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