نتایج جستجو برای: wind speed
تعداد نتایج: 276062 فیلتر نتایج به سال:
the major problem of wind turbines is the great variability of wind power production. the dynamic change of the wind speed returns the quantity of the power injected to networks. therefore, wind–thermal generation scheduling problem plays a key role to implement clean power producers in a competitive environment. in deregulated power systems, the scheduling problem has various objectives than i...
abstract climate variability empowers critical consequences on sustainability of soil and water resources. in this paper the trend of annual and seasonal time scale of temperature (minimum, maximum, average), relative humidity (minimum, maximum, average), precipitation, wind speed, extreme events, cloudiness, reference evapotranspiration employing mann-kendall and least square errors were studi...
Transient responses of sap flow to step changes in wind speed were experimentally investigated in a wind tunnel. A Granier-type sap flow sensor was calibrated and tested in a cylindrical tube for analysis of its transient time response. Then the sensor was used to measure the transient response of a well-watered Pachira macrocarpa plant to wind speed variations. The transient response of sap fl...
Wind measurement is important for estimating wind energy potential, but it is relatively cost-intensive and often conducted at a narrow height from the ground level. The typical range of most turbine hub heights is from 30-50 m or even higher. Extrapolation on wind data thus becomes necessary to estimate the wind speed at different heights. Doing so requires the essential understanding of wind ...
Introduction: Energy as a contributor to human well-being plays an important role in the sustainable development of human societies. The growing demand for energy, higher standards of living, global warming, and decreasing fossil fuel resources have focused the global attention on renewable energies (Kaya and Kahraman, 2010). Owing to the rapid development of wind energy extraction technologies...
We study the Cauchy-Matern CM process with long-range dependence LRD . The closed form of its power spectrum density PSD function is given. We apply it to model the autocovariance function ACF and the PSD of the sea surface wind speed wind speed for short observed in the Lake Worth, Florida, over the 1984–2006 period. The present results exhibit that the wind speed at the Lake Worth over 1984–2...
In this work, a second-order sliding mode control algorithm is proposed for variable speed laboratory size DC generator wind turbine experiment system in order to track a speed profile and operate the wind turbine at maximum power extraction. The turbine torque, which varies with the wind speed, is considered as an unknown disturbance and rejected by the sliding mode strategy. The sliding mode ...
System identification techniques are powerful tools that help improve modeling capabilities of real world dynamic systems. These techniques are well established and have been successfully used on countless systems in many areas. However, wind turbines provide a unique challenge for system identification because of the difficulty in measuring its primary input: wind. This thesis first motivates ...
Modern utility-scale wind turbines are typically controlled using yaw, generator torque, and blade pitch actuation (Pao and Johnson, 2011). The yaw motor is used to align the rotor with the wind direction for the purpose of maximizing power capture. Generator torque is controlled during below-rated (region 2) operation to maximize power capture by maintaining the optimal tip speed ratio. In abo...
In this paper, the spatio-temporal (multi-channel) linear models, which use temporal and the neighbouring wind speed measurements around the target location, for the best short-term wind speed forecasting are investigated. Multi-channel autoregressive moving average (MARMA) models are formulated in matrix form and efficient linear prediction coefficient estimation techniques are first used and ...
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