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Search Results: 1 - 10 of 2661 matches for " Wind Turbines "
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Exergy Analysis of Single Array Wind Farm Using Wake Effects  [PDF]
A. Jeya Saravanan, C. P. Karthikeyan, Anand A. Samuel
Engineering (ENG) , 2011, DOI: 10.4236/eng.2011.39117
Abstract: The influence of wake parameters on the exergy analysis of single array wind farm is studied in this paper. Key parameters which influence wake effects in a wind farm are wind velocity, tip speed ratio, number of blades, rotor speed, rotor diameter and hub height. Three different models namely power, wake and exergy model were used in estimating the exergy efficiency of the single array wind farm. Even though it is ideal for wind farms to fix the wind turbines in rows and columns the conditions of the site may not always be condu- cive for it. Hence analysis has been done keeping the wind turbines at random in a row and the effect of positioning on the performance is analyzed. Energy and exergy efficiency calculations were made for different cases by varying the positions of wind turbines in the single array wind farm. Standard relations were used in estimating the energy deficit in the wind farm due to wake effects. The wake effects were found to have an aggregated influence on the energy production of the wind farm, which results from the changes in the key parameters mentioned above. Potential areas for reducing energy losses by proper location and selection of turbines based on rating are highlighted. The influence of individual parameters contributing to the wake ef-fect were analyzed and discussed in detail.
Design and Development of a Wind Turbine Simulator Using a Separately Excited DC Motor  [PDF]
K. K. M. S. Kariyawasam, K. K. N. P. Karunarathna, R. M. A. Karunarathne, M. P. D. S. C. Kularathne, K. T. M. U. Hemapala
Smart Grid and Renewable Energy (SGRE) , 2013, DOI: 10.4236/sgre.2013.43031
Abstract: Over the course of the past decade, power generation based on wind energy has become a significant component in modern power systems, which has caused substantial increase in the wind power based research. As it is complicated to use a real wind turbine for laboratory purposes, development of a replica of a real wind turbine that can be connected and used indoors is imperative. This paper presents the design and development of a wind turbine simulator that operates on the typical power-speed characteristics of a wind turbine. First, the mathematical model of the wind turbine simulator is developed and the corresponding CAD simulations are carried out. Proposed hardware implementations involve a DC motor-DC generator set, a variable load and a control system based on PI controllers. It is a simple, low power and low cost design that can be easily connected to an AC system through an inverter.
Vientos extremos en la provincia de Neuquén
Lassig,Jorge L.; Palese,Claudia; Apcarian,Anabel;
Meteorologica , 2011,
Abstract: the objective of this work is to calculate the extreme values of wind speed with different models proposed in international standards that are utilized so much in the design of wind farms as in civil structures. the employed models are described and the calculations are carried out in 5 places of the neuquén province, utilizing data of winds measured whose series have between 8 months and 5 years of length. the extreme values are obtained with a return period of 50 years and they correspond to the extreme of the 10-minute and 3-second average wind speed. the found values are analysed and it are compared among them, with measurements and with values proposed in the standard of security of civil structures of argentina. the extremes values that were estimated according to the european wind turbine standards ii do not underestimate the available measurements and the smaller differences observed with the results of the other models correspond to the longest series. the shape parameter of the weibull distribution and the sample length (time period) would be the most important factors in the estimations of the extremes values of wind speed.
Simulación de la Producción de Energía Eléctrica con Aerogeneradores de Peque?o Tama?o
Araújo,Alex M; Melo,Gilberto M; de Medeiros,Armando L. R; dos Santos,Maurílio J;
Información tecnológica , 2009, DOI: 10.4067/S0718-07642009000300006
Abstract: this paper presents a simulation of electricity production from several small wind turbines in the wind regime of olinda-pe-brazil, taking into account a number of records wind speeds and temperature in 1998, with the aim of developing a performance analysis tool that allows its selection. the hourly wind speed data were discretized at appropriate intervals to allow better handling of the information contained in the curves of electricity, supplied by manufacturers. the tool allows a comparative analysis of the performance of wind turbines, both in the aspect of the electrical energy production as its efficiency in function of wind speed. the results show that of the local wind regime influenced the production of electricity and that the data provided by manufacturers must be certified.
Modelo de análisis de cargas máximas en aerogeneradores producidas por vientos extremos
Herrera - Sánchez,Omar; Schellong,Wolfgang; González - Fernández,Vladimir;
Ingenier?-a Mec??nica , 2010,
Abstract: abstract the use of the wind energy by means of the wind turbines in areas of high risk of occurrence of hurricanes comes being an important challenge for the designers of wind farm at world for some years. the wind generator is not usually designed to support this type of phenomena, for this reason the areas of high incidence of tropical hurricanes of the planning are excluded, that which, in occasions disables the use of this renewable source of energy totally, either because the country is very small, or because it coincides the area of more potential fully with that of high risk. to counteract this situation, a model of analysis of maxims loads has been elaborated taken place the extreme winds in wind turbines of great behavior. this model has the advantage of determining, in a chosen place, for the installation of a wind farm, the micro-areas with higher risk of wind loads above the acceptable for the standard classes of wind turbines.
Power generation from wind turbines in a solar chimney
Tudor Foote, Ramesh K. Agarwal
International Journal of Energy and Environment , 2013,
Abstract: Recent studies have shown that shrouded wind turbines can generate greater power compared to bare turbines. A solar chimney generates an upward draft of wind inside a tower and a shroud around the wind turbine. There are numerous empty silos on farms in the U.S. that can be converted to solar chimneys with minor modifications at modest cost. The objective of this study is to determine the potential of these silos/chimneys for generating wind power. The study is conducted through analytical/computational approach by employing the commercial Computational Fluid Dynamics (CFD) software. Computations are performed for five different geometric configurations consisting of a turbine, a cylindrical silo, and/or a venturi and/or a diffuser using the dimensions of typical silos and assuming Class 3 wind velocity. The incompressible Navier-Stokes equations with the Boussinesq approximation and a two equation realizable k – ε model are employed in the calculations, and the turbine is modeled as an actuator disk. The power coefficient (Cp) and generated power are calculated for the five cases. Consistent with recent literature, it was found that the silos with diffusers increase the Cp beyond Betz’s limit significantly and thus the generated power. It should be noted that Cp is calculated by normalizing it by the turbine area swept by the wind. This study shows the potential of using abandoned silos in the mid-west and other parts of the country for localized wind power generation.
Problems of Determining Size and Character of Wind Turbines’ Visual Impact Zones on Lithuanian Landscape
Jonas Abromas,Jūrat? Kami?aityt?-Virba?ien?
Environmental Research, Engineering and Management , 2013, DOI: 10.5755/j01.erem.62.4.2363
Abstract: landscape variety, time of the day, and other factors (Tsoutsos et al., 2009). In this paper the factors that influence the wind turbine’s visibility are analyzed. One of the most important aspects determining wind turbine’s visual impact is observation distance. The visual impact zones of wind turbines in different countries having been analyzed and the situation in Lithuania taken in, the Table of wind turbine’s visual impact hypothetical degrees is set up. To determine the precision of visual impact degrees, the survey in situ is done and its results have been compared to the theoretical-hypothetical visual impact degrees (a comparative analysis). Visual impact zones of wind turbines are evaluated from ten pre-selected observation points. Six wind turbines (of 2 MW power each), installed in Kretinga district near village Vydmantai, are analyzed. At the end of the study, it is identified that the categorization of visual impact zones of wind turbines should be corrected in accordance with the visual character of Lithuanian landscape. Different observation distances have a great influence on the significance of a visual impact. Being 0-7 km from the wind farm (in this case the wind turbine’s visual impact on the landscape varies from dominants to subdominants), the intervals of observation distances have to be shorter. It is noticed that forests, buildings, and other vertical objects that are located near the observation point change the visual impact significance very much. Weather conditions make significant influence as well, especially on visibility of wind turbine wheels. DOI: http://dx.doi.org/10.5755/j01.erem.62.4.2363
Analysis of Transient Phenomena Due to a Direct Lightning Strike on a Wind Energy System
Rafael B. Rodrigues,Victor M. F. Mendes,Jo?o P. S. Catal?o
Energies , 2012, DOI: 10.3390/en5072545
Abstract: This paper is concerned with the protection of wind energy systems against the direct effects of lightning. As wind power generation undergoes rapid growth, lightning damages involving wind turbines have come to be regarded as a serious problem. Nevertheless, very few studies exist yet in Portugal regarding lightning protection of wind energy systems using numerical codes. A new case study is presented in this paper, based on a wind turbine with an interconnecting transformer, for the analysis of transient phenomena due to a direct lightning strike to the blade. Comprehensive simulation results are provided by using models of the Restructured Version of the Electro-Magnetic Transients Program (EMTP), and conclusions are duly drawn.
Design and Fabrication of Convergent Wind Mill
Mr. K.Maharaja,Mr.S.N.Vijayan,Mr.S.Sendhil Kumar
International Journal of Recent Technology and Engineering , 2013,
Abstract: Nowadays electrical energy is very essential for human beings to fulfill the requirements of day to day activities in various measures. The demand of the electrical energy increases day by day. It is most essential to promote renewable energies so that they definitely become a strong alternative to generate electrical power for small scale needs of society. This paper discusses the convergent horizontal axis wind mill which uses the bicycle wheel instead of using propeller blades for producing power. Design of the horizontal axis wind mill is discussed and presented in this paper considering the various design factors. The results observed through various experiments in the various time zones which validate the results obtained analytically.
Vibration Signals and Condition Monitoring for Wind Turbines  [PDF]
Dimitrios Koulocheris, Georgios Gyparakis, Andonios Stathis, Theodore Costopoulos
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.512116

Rolling element bearings are critical parts of modern wind turbines as they carry the loads of the turning structure and the wind force. The stochastic nature of the wind loads makes it difficult to estimate the useful operational life of the bearings. Condition monitoring of these bearings in a real time environment could be very helpful in estimating their performance and in scheduling maintenance actions when a condition-based maintenance strategy is followed. This procedure can be successfully implemented by using vibration analysis in the time domain or in the frequency domain, giving useful results about the current condition of bearings and the location of potential faults. Permanently located transducers on proper positions on the bearings’ housings can be used in order to collect, process and evaluate real time measurements and provide information about the bearing’s performance. In this work, a test rig is utilized in order to evaluate the performance of rolling bearings. The results of the experimentation are satisfactory and the progress of fatigue failures can be predicted through vibration analysis techniques showing that implementation in real scale may be useful.

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