Browsing by Subject "Wind turbines"
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Item Analysis of the correlation between wind power generation and system response characteristics following unit trips on the ERCOT grid(2010-05) Lovelace, William Edward; Grady, W. M.; Santoso, SuryaElectric power generation using wind turbines is on the rise in not only the United States but the entire globe. While the benefits from such methods of generation include clean and renewable energy, wind turbines may pose a potential risk to the stability of grid operation. Wind turbine generators are similar to conventional generators; however, the manner with which the wind turbine is coupled to the grid may reduce system inertia and increase the magnitude of transient stability problems. This study empirically examines the effect of wind generation on ERCOT system response characteristics following unit trips such as frequency drop, and phasor oscillation frequency and damping. It is shown with a high degree of certainty that an increase in wind generation is leading to a greater phasor oscillation frequency and lesser system inertia. Wind generation may also be leading to less system damping and smaller power frequency drops.Item Analysis of the temperature effects related to power generation surrounding wind turbine installations southwest of Abilene, Texas(2022-12-02) Crues, Ashton Grace; King, Carey Wayne, 1974-; Yang, Zong-liang; Helper, MarkThe wind farms in Texas southwest of Abilene are some of the oldest in the United States and have provided many researchers the opportunity to study the long-term effects of wind turbines on the environment. The principal objective of this thesis was to compare 2020 maximum and minimum land surface temperatures on both high- and low-generation days within and adjacent to an Abilene wind farm. This work shows the impact of turbine placement on differential temperature ranges and on diurnal temperatures and temperature ranges between and within high- and low-power generation days. I used National Aeronautics and Space Administration (NASA) 1-kilometer temperature data and QGIS for temperature differential, defined as the temperature difference at a specific location within a specific area compared to the same average difference for a control area outside of turbine influence. I compared temperature differentials within 1 km of wind turbines to those at 5 km or greater from the nearest turbine to define areas inside versus outside of turbine influence. First, the LST datasets show a statistically significant lower average temperature within wind farms compared to the average outside the farms for the high-generation day. Second, the LST datasets show a small but statistically significant higher average temperature within wind farms for low-generation day minimum temperatures. Third, there is no statistically significant average temperature difference between wind farms and areas outside of them when considering low-generation day maximum temperatures. The between generation days analysis reveals that the average difference in temperatures between high- and low-generation days within the wind farms was less than this same average difference outside of the wind farms. The high-generation day was associated with a slightly greater average range of diurnal temperature within wind farms compared to the average diurnal temperature range outside of the wind farms. The same isn’t true for the low-generation day, where there was no statistically significant difference in average diurnal temperature range. The Horse Hollow wind farm and adjacent turbines on high power generation days are associated with a noticeable land surface temperature decrease within the wind farm compared to the surrounding area.Item Computation of near-field distribution around wind turbines(2014-05) Liu, Xiao, active 21st century; Ling, HaoIn this work, two approaches for computing the near-field distribution around wind turbines are proposed, including: (1) Huygens Principle and (2) the parabolic equation technique. In order to simplify the problem, the cylinder model is utilized to represent the wind turbines and transform the problem into a two-dimensional case. To make Huygens Principle computationally tractable, several approximations are made based on the problem geometry especially modelling the cylinder as a plate. The expression of the electromagnetic field radiated by the equivalent magnetic current can be analytically solved by the error function. To verify the results, FEKO is utilized to simulate the scattering of infinitely long cylinders using periodic boundary condition (PBC). In order to solve the problem of multiple cylinders, a modified method is derived. For more accurate results, the parabolic equation (PE) technique is utilized to solve this problem, which is usually utilized to solve wave propagation problems. In this case, wide-angle approximation is used to solve the parabolic equation, which can obtain accurate results in a region of up to 45 degrees. Although these two approaches are not full-wave simulation, the calculation time is significantly reduced and the error is acceptable. To further verify the computed results by the parabolic equation technique, two commercial transceivers from Time Domain Corporation are used to measure the field distribution behind a finite-length metal pole. The frequency-domain results are obtained from the measured time-domain results using the fast Fourier transform. It is shown that the computed results by the parabolic equation technique agree well with the measurement results.Item Dynamic models for wind power plants(2011-08) Singh, Mohit, 1982-; Santoso, Surya; Grady, William M.; Driga, Mircea; Muljadi, Eduard; Longoria, Raul G.Manufacturer-specific models of wind turbines are favored for use in wind power interconnection studies. While they are detailed and accurate, their usages are limited to the terms of the non-disclosure agreement, thus stifling model sharing. The primary objective of the work proposed is to develop universal manufacturer-independent wind power plant models that can be shared, used, and improved without any restrictions by project developers, manufacturers, and engineers. Each of these models includes representations of general turbine aerodynamics, the mechanical drive-train, and the electrical characteristics of the generator and converter, as well as the control systems typically used. In order to determine how realistic model performance is, the performance of the one of the models (doubly fed induction generator model) has been validated using real-world wind power plant data. This work also documents selected applications of these models.Item Offshore wind turbine loads under the coupled influences of wind, waves, and currents during hurricanes(2015-05) Kim, Eungsoo; Manuel, Lance; Kinnas, Spyros A; Fu, Rong; Kallivokas, Loukas F; Basu, SukantaIn the United States, potential offshore wind plant sites have been identified along the Atlantic seaboard and in the Gulf of Mexico. At such sites, it is imperative that we consider load cases for and define external conditions associated with hurricanes and severe winter storms for which wind turbines may need to be designed. We select two hurricanes, Ike (2008) and Sandy (2012), and investigate what effect these tropical storms would have on bottom-supported offshore wind turbines that were hypothetically in or close to their path as they made landfall. For realistic turbine loads assessment, it is important that the coupled influences of the changing wind, wave, and current fields are simulated throughout the evolution of the hurricanes. We employ a coupled model—specifically, the University of Miami Coupled Model (UMCM)—that integrates atmospheric, wave, and ocean components to produce needed wind, wave, and current data. The wind data are used to generate appropriate vertical wind profiles and full wind velocity fields including turbulence; the current field over the water column is obtained by interpolated discrete output current data; and short-crested irregular second-order waves are simulated using output directional wave spectra from the coupled model. Two monopile-supported offshore wind turbines sited in 20 meters of water in the Gulf of Mexico are studied so as to estimate loads during Hurricane Ike; a jacket space-frame platform-supported offshore wind turbine sited in 50 meters of water in the mid-Atlantic region is studied so as to estimate loads during Hurricane Sandy. We discuss in detail how the simulated hurricane wind, wave, and current output data are used in turbine loads studies. We discuss important characteristics of the external conditions including the relative importance of swell versus wind seas, of aerodynamic versus hydrodynamic forces, of current velocity effects, of yaw control options for the turbine, of hydrodynamic drag versus inertia forces, and of soil-structure interaction effects. A detailed framework is presented that explains how coupled inputs can be included in turbine loads studies during a hurricane; this can aid in future efforts aimed at developing offshore wind turbine design criteria and load cases related to hurricanes.Item Pitch control of wind turbines(2005-05-21) Dhar, Shirali; Womack, Baxter F., 1930-This thesis discusses the Pitch control of wind turbines. Analysis of open and closed loop control system using a PID controller for a simple pitch control system is discussed. A Simulink simulation is performed to analyze the system response to the outside disturbancesItem The future of Texas offshore wind : analyzing case studies(2022-12-14) Swales, William David; Eaton, David J.; Faust, Kasey; Thomas, Dana; Berry, NicoleOffshore wind energy can generate renewable energy and Northern Europe already uses it as an electricity source (windeurope.org, n.d.). While some in the United States (US) have been reluctant to embrace offshore wind power, the Biden administration has advocated increasing East-Coast offshore wind power generation to up to 30 gigawatts (Eilerin & Dennis, 2021). In 2020, Texas generated approximately 20 percent of its electricity from onshore wind turbines (EIA, Today in Energy, 2020). Texas has not invested in offshore wind energy generation along hundreds of miles of available Gulf of Mexico coastline. This study describes environmental impacts case studies of previously developed United States offshore wind farms to establish recommendations for what an offshore wind farm in Texas could look like. Two case studies along the Texas Gulf Coast are used as potential guides for future Texas offshore wind development. An analysis of infrastructure requirement, environmental impacts, policy and levelized cost of energy is included to inform recommendations for further wind developments. The levelized cost of energy (LCOE) of offshore wind is compared with costs of natural gas combined cycle electricity to estimate the approximate comparative cost of those sources through 2050. Such an analysis does not deal with the real full costs, benefits, and risks of offshore wind generation, nor does it define the full range of demand and supply options for Texas’ electricity supply options. However, based on data from the Energy Information Agency and other sources, this limited LCOE provides a context for costs associated with offshore wind. The 2021 Texas winter storm exposed the vulnerability of Texas’ electrical grid. Texas would benefit from more reliable and stable energy capacity to meet demands of a rapidly growing population in one of the fastest growing states in the country. An offshore wind industry could provide security to Texas’ energy future if it represents a wise investment. This study provides a case study guide with recommendations for possible wind farm creation off the Texas Gulf Coast.Item Wind energy harvesting for bridge health monitoring(2011-05) McEvoy, Travis Kyle; Wood, Kristin L.The work discussed in this thesis provides a review of pertinent literature, a design methodology, analytical model, concept generation and development, and conclusions about energy harvesting to provide long-term power for bridge health monitoring. The methodology gives structure for acquiring information and parameters to create effective energy harvesters. The methodology is used to create a wind energy harvester to provide long-term power to a wireless communication network. An analytical model is developed so the system can be scaled for different aspects of the network. A proof of concept is constructed to test the methodology's effectiveness, and validate the feasibility and analytical model.