On the Rotor Effects upon Nacelle Anemometry for Wind Turbines

Smaïli, Arezki; Masson, Christian

doi:10.1260/0309524043729958

Cited by 30 publications

(23 citation statements)

References 6 publications

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“…Subsequently, some researchers have investigated the applicability of operational nacelle wind data towards inflow research. An obstacle to such research is the modification of nacelle-sampled flow by the turbine structure and rotor circulation, which can cause these measurements to nonlinearly deviate from free-stream values (Antoniou and Pedersen 1997, Smith et al 2002, Smaïli and Masson 2004. Nacelle transfer functions (NTFs), relationships between the nacelle-measured winds and free-stream winds, can be used to prepare nacelle data for use in power output studies, provided that conditions on the data collection platforms are met (Liu 2011).…”

Section: Introductionmentioning

confidence: 99%

The modification of wind turbine performance by statistically distinct atmospheric regimes

Vanderwende

Lundquist

2012

Environ. Res. Lett.

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Power production from wind turbines can deviate from the manufacturer's specifications due to variability in atmospheric inflow characteristics, including stability, wind shear and turbulence. The practice of insufficient data at many operational wind farms has made it difficult to characterize this meteorological forcing. In this study, nacelle wind measurements from a wind farm in the high plains of central North America were examined along with meteorological tower data to quantify the effects of atmospheric stability regimes in the boundary layer on turbine power generation. The wind power law coefficient and the bulk Richardson number were used to segregate time periods by stability to generate regime-dependent power curves. Results indicated underperformance during stable regimes and overperformance during convective regimes at moderate wind speeds (8-12 m s −1 ). Statistical testing using the Monte Carlo approach demonstrated that these results were robust, despite potential deviations of the nacelle wind speeds from free-stream inflow values due to momentum loss from the turbine structure and spinning rotor. A hypothetical stability dependence between free-stream and nacelle wind speeds was generated that can be evaluated in future analyses. The low instrumentation requirement of our power analysis technique should enable similar studies at many wind sites formerly considered inappropriate.

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Section: Introductionmentioning

confidence: 99%

The modification of wind turbine performance by statistically distinct atmospheric regimes

Vanderwende

Lundquist

2012

Environ. Res. Lett.

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“…Several studies have found that nacelle anemometer measurements can be adjusted by the use of transfer functions between an upwind hub-height measurement and the nacellemounted anemometer measurement (Antoniou and Pedersen, 1997;Hunter et al, 2001, Smith et al, 2002Smaïli and Masson, 2004). The IEC (2013) standard now allows the use of nacelle-mounted anemometers to verify power curves based on these transfer functions, or fitted functions of correction factors between upwind hub-height wind speed (UHWS) measurements and nacelle-mounted anemometer wind speed (NAWS) measurements.…”

Section: Introductionmentioning

confidence: 99%

“…In previous work, the relationship between UHWS measurements and NAWS measurements has been found to depend on multiple factors, including rotor and turbine control settings such as blade pitch angle and inflow angle, the use of vortex generators, yaw error, terrain, flow induction, calibration of the anemometer, and nacelle height and position (Antoniou and Pedersen, 1997;Dahlberg et al, 1999;Smith et al, 2002;Smaïli and Masson, 2004;Frandsen et al, 2009;Zahle and Sørensen, 2011).…”

Section: Introductionmentioning

confidence: 99%

Atmospheric turbulence affects wind turbine nacelle transfer functions

Martin¹,

Lundquist

Clifton

et al. 2017

Wind Energ. Sci.

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Abstract. Despite their potential as a valuable source of individual turbine power performance and turbine array energy production optimization information, nacelle-mounted anemometers have often been neglected because complex flows around the blades and nacelle interfere with their measurements. This work quantitatively explores the accuracy of and potential corrections to nacelle anemometer measurements to determine the degree to which they may be useful when corrected for these complex flows, particularly for calculating annual energy production (AEP) in the absence of other meteorological data. Using upwind meteorological tower measurements along with nacelle-based measurements from a General Electric (GE) 1.5sle model, we calculate empirical nacelle transfer functions (NTFs) and explore how they are impacted by different atmospheric and turbulence parameters. This work provides guidelines for the use of NTFs for deriving useful wind measurements from nacelle-mounted anemometers. Corrections to the nacelle anemometer wind speed measurements can be made with NTFs and used to calculate an AEP that comes within 1 % of an AEP calculated with upwind measurements. We also calculate unique NTFs for different atmospheric conditions defined by temperature stratification as well as turbulence intensity, turbulence kinetic energy, and wind shear. During periods of low stability as defined by the Bulk Richardson number (R B ), the nacelle-mounted anemometer underestimates the upwind wind speed more than during periods of high stability at some wind speed bins below rated speed, leading to a steeper NTF during periods of low stability. Similarly, during periods of high turbulence, the nacelle-mounted anemometer underestimates the upwind wind speed more than during periods of low turbulence at most wind bins between cut-in and rated wind speed. Based on these results, we suggest different NTFs be calculated for different regimes of atmospheric stability and turbulence for power performance validation purposes.

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“…Nacelle‐based observations were originally considered to be too inaccurate for power performance testing since they are influenced by an interference from the nacelle and the moving blades of the wind turbine . Consequently, some studies have looked at numerical modeling of the wind flow around the nacelles to better understand and potentially correct such interferences . Each paper makes some useful recommendations on the treatment of nacelle‐based measurements, including discussions on the location of the anemometers on the nacelle.…”

Section: Introductionmentioning

confidence: 99%

“…14 Consequently, some studies have looked at numerical modeling of the wind flow around the nacelles to better understand and potentially correct such interferences. 12,15 Each paper makes some useful recommendations on the treatment of nacelle-based measurements, including discussions on the location of the anemometers on the nacelle.…”

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confidence: 99%

Using nacelle‐based wind speed observations to improve power curve modeling for wind power forecasting

2011

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Wind power forecasting for projection times of 0–48 h can have a particular value in facilitating the integration of wind power into power systems. Accurate observations of the wind speed received by wind turbines are important inputs for some of the most useful methods for making such forecasts. In particular, they are used to derive power curves relating wind speeds to wind power production. By using power curve modeling, this paper compares two types of wind speed observations typically available at wind farms: the wind speed and wind direction measurements at the nacelles of the wind turbines and those at one or more on‐site meteorological masts (met masts). For the three Australian wind farms studied in this project, the results favor the nacelle‐based observations despite the inherent interference from the nacelle and the blades and despite calibration corrections to the met mast observations. This trend was found to be stronger for wind farm sites with more complex terrain. In addition, a numerical weather prediction (NWP) system was used to show that, for the wind farms studied, smaller single time‐series forecast errors can be achieved with the average wind speed from the nacelle‐based observations. This suggests that the nacelle‐average observations are more representative of the wind behavior predicted by an NWP system than the met mast observations. Also, when using an NWP system to predict wind farm power production, it suggests the use of a wind farm power curve based on nacelle‐average observations instead of met mast observations. Further, it suggests that historical and real‐time nacelle‐average observations should be calculated for large wind farms and used in wind power forecasting. Copyright © 2011 John Wiley & Sons, Ltd.

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On the Rotor Effects upon Nacelle Anemometry for Wind Turbines

Cited by 30 publications

References 6 publications

The modification of wind turbine performance by statistically distinct atmospheric regimes

The modification of wind turbine performance by statistically distinct atmospheric regimes

Atmospheric turbulence affects wind turbine nacelle transfer functions

Using nacelle‐based wind speed observations to improve power curve modeling for wind power forecasting

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