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COMPARISON OF A PULSED DOPPLER LiDAR WITH A 200 M MET MAST IN COMPLEX TERRAIN. Tobias Klaas 1 , Doron Callies 1 Christoph Langenmayr 1 ,Lukas Pauscher 1 , Saskia Hagemann 1 , Zouhair Khadiri-Yazami 1 , Bernhard Lange 1 (1) Fraunhofer IWES, Kassel, Germany . Outline. - PowerPoint PPT Presentation


<p>Folie 1</p> <p>COMPARISON OF A PULSED DOPPLER LiDAR WITH A 200 M MET MAST IN COMPLEX TERRAINTobias Klaas1, Doron Callies1 Christoph Langenmayr1,Lukas Pauscher1, Saskia Hagemann1, Zouhair Khadiri-Yazami1, Bernhard Lange1 (1) Fraunhofer IWES, Kassel, Germany </p> <p> Fraunhofer IWES10 sec1OutlineMeasurement site at Rdeser BergSite description, measurement campaign, data basisLiDAR measurements in complex terrainPerformance of LiDAR vs. mast measurementsCorrection with WAsP Engineering and Meteodyn WTPredicted bias compared to measured differenceVirtual met mastConclusion and Outlook</p> <p> Fraunhofer IWES20 sec2</p> <p>Project Utilization of Inland Wind Power</p> <p>Source: RP Kassel, 2012Source: Die Auswrtige Presse, 2011Complex TerrainForestNew onshore windturbinesMesoscale modellingProject duration 2012 2014Wind characteristics, LiDAR measurements, onshore wind energy potential Fraunhofer IWES</p> <p>Measurement location in central GermanySource: Google Earthmeasurement siteWind measurements in complex terrain at Rdeser BergTypical wind farm location in central / south Germany</p> <p> Fraunhofer IWES30 sec4</p> <p>Mast layout and specifications</p> <p>200 m wind measurement mast in complex forested terrain IEC conform booms with 5,40 m length, orthogonal to main wind direction13 measurement heightsCo-located LiDAR measurements with LEOSPHERE Windcube WLS7 V1</p> <p> Fraunhofer IWES1 min5Measurement campaign and data processingMast - LiDAR comparisonMeasurement period: 21 Jan 30 June 2012 Periods of icing were removed by visual comparison of heated vs. unheated cupsInvalid and/or physically unreasonable values were removedMeasurements are compared at 120, 160 and 200 mMean wind profileScatter plots and linear regressionDiurnal patternDirectional dependence of bias Due to terrain complexity and wind LiDAR measurement principle we expect significant bias.</p> <p> Fraunhofer IWES1 min6LiDAR availability with height</p> <p>More than 80% of measured valuesin 10 minute averaging interval must be availablePeriods of rain were removed</p> <p>Availability decreases with height:85 % at 135m60 % at 200m Fraunhofer IWES30 sec7LiDAR vs. mast measurements:Mean wind profile</p> <p>Mean profile fits well, LiDAR shows small underestimationStrong effects from forest and terrain below 60m height Fraunhofer IWES30 sec8LiDAR vs. mast measurements:scatter plot at 120 m and 200 m</p> <p>Compared to flat terrain (Hovsre) the scatter is significantly higherSource: Gottschall, Courtney 2010 Fraunhofer IWES1 min9LiDAR vs. mast measurements:Diurnal variation at different heights</p> <p>Significant diurnal pattern at all heightsDeviations between mast and LiDAR increase during nighttime Fraunhofer IWES1 min10</p> <p>LiDAR vs. mast measurements:Directional dependence at 120 monly wind speeds &gt; 4m s-1Mean bias approx. between -4% and +2% Fraunhofer IWES2 min11</p> <p>only wind speeds &gt; 4m s-1</p> <p>LiDAR vs. mast measurements:Directional dependence at 120 mPositive deviation for flow along the ridge Fraunhofer IWES30 sec12</p> <p>LiDAR vs. mast measurements:Directional dependence at 120 mSignificant underestimation in main wind directiononly wind speeds &gt; 4m s-1</p> <p> Fraunhofer IWES30 sec13</p> <p>LiDAR vs. mast measurements:Directional dependence with heightLightning rodonly wind speeds &gt; 4m s-1Shape and mean bias similar for all heightsHeight dependency of about 1%, depending on sector Fraunhofer IWES1 min14LiDAR correction with flow simulationLiDAR measurement bias is mainly caused by flow inhomogeneityFlow simulation can be used to assess the wind conditions and develop correction methodsWAsP Engineering with Bingls correction scriptMeteodyn WT and LiDAR correction module</p> <p>measurement sitemain wind dir.Source: Bingl 2009 Fraunhofer IWES30 sec15Comparison of different correction algorithms to measured biasWEng estimation is much too high, but the pattern is reproducedBias estimated by Meteodyn WT fits much better, but is slightly too low</p> <p> Fraunhofer IWES1 min16Correction with Meteodyn WT:Predicted bias for three heightsLess symmetry in estimation due to CFD simulationHeight-dependency of bias for certain sectors</p> <p> Fraunhofer IWES1 min17</p> <p>Three Windcube v1 LiDARs mounted on maneuverable tilting platformsFocusing of the three laser beams on one pointAutomatically measuring heights from 40m to 200mResults were compared to the 200m mast at Rdeser BergRealization of a virtual met mast using three Pulsed Doppler LiDARs </p> <p> Fraunhofer IWES2 minutes18ConclusionsLiDAR shows error in complex terrain:Patterns follow orography, effects are site specificDeviation follows same pattern at all heights (up to 200m!)Deviations approx. between -4% and +2% Compensating effects in mean wind profileDeviations during night time</p> <p>Meteodyn and WEng correction:Shape of predicted bias fits (fairly) well for both toolsBias predicted by WEng is much too highVery good reproduction of bias by Meteodyn WT Fraunhofer IWES2 minutes19OutlookDetailed evaluation of flow models at complex site with mast dataDifferent stabilitiesDifferent forest/roughness parameterizationLiDAR vs. Mast in complex terrain at several other complex sitesMore complex sites, more forested sitesEvaluation of different CFD-tools for LiDAR correctionMeteodyn WT / WindSim / WEng / OpenFoam3D-LiDAR experimentsDetailed comparison of virtual vs. real met. mast Fraunhofer IWES1 minute20M. Sc. Tobias</p> <p>Fraunhofer Institute for Wind Energy and Energy System Technology IWES Knigstor 59, 34119 Kassel, Germany </p> <p>Thank you for your attentionVisit us at stand B-B77!Do not miss our related posters and presentations:Pauscher, Lukas: Wind over complex, forested terrain: First year of measurement with 200m research mastTuesday, 5 February 2013,Room: LEHAR 2-4,11:00 - 12:30 Wind Resources - Moving the barriers (part 1)Khadiri-Yazami, Zouhair: The realization of a Virtual met mast based on three Doppler wind LiDAR, Poster No. 404 Fraunhofer IWES21</p>