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Field-test of nacelle-based lidar to explore its applications for Vattenfall as wind park operator
Monday, 18 May 2015
Stefan Goossens
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Content
(Research objective I)
(Research objective II)(Research objective III)(Research objective IV)(Research objective V)
Measurement campaignWorking principleExperienceValidation1. Power curve2. Yaw misalignment3. Blockage effect Financial feasibilityConclusions and RecommendationsQuestions
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Measurement campaign
• Slufterdam West• Wind Iris installed 18 September 2014• Sodar installed 13 October 2014• Campaign length: 3 months
Photo: Havenbedrijf Rotterdam N.V., Projectorganisatie Maasvlakte 2
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Experience
• Installation ~8 hours by 4 technicians, no major issues
• Easy access to data; good availability (90%)• Data processing relatively straightforward• Good support during the campaign from Oldbaum• Plenty of literature and guidelines for comparison and
verification
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Validation
Comparison to on-site sodar• Wind Iris is able to measure 10-min
wind speed accurately: good
correlation, in accordance with
literature
• Turbulence intensity questionable
• YM measurement less accurate than
anticipated: 4°vs 0.5°
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1. Power curve
• Wind speed at hub height and 2.5D• Power measurement requires more certainty to be IEC
compliant• Density correction• Shear & Veer
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2. Yaw misalignment
What is the ideal yaw misalignment when it comes to the power curve?
A small angle (~5 degrees)90 degrees
As close to zero as possible?
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• Mean yaw misalignment: 1.5 degrees• 0 degrees yaw misalignment not necessarily best?
2. Yaw misalignment
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2. Yaw misalignment
??
What is the ideal yaw misalignment when it comes to the power curve?
A small angle (~5 degrees)90 degrees
As close to zero as possible
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Financial feasibility
• Strongest drivers of ROI:• Purchase costs
• PV improvement factor
• Break even point (ROI 0%) for PV improvement of 1.2%
• Implementation not recommended due to uncertainty in PV improvement
• Financially attractive if power curve improvement can be quantified
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Conclusions
• Wind Iris advantages:• Power curve measurement
• R&D applications (e.g. blockage)
• Wind Iris disadvantages:• Yaw misalignment measurement less accurate than anticipated
• No density, shear and veer measurements (yet)
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Recommendations
• Use Wind Iris for PV measurement, R&D and if large yaw misalignment is suspected
• More research to investigate effect of yaw misalignment on the PV curve (e.g. intentional YM)
• Implementation recommended if PV improvement can be quantified
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Research objectives
I. Gain experience with the installation and operation of the Avent Wind Iris,
as well as the collection and analysis of the data, considering that a good
dataset is a prerequisite for further analysis.
II. Determine the power curve based on lidar.
III. Determine how much Slufterdam West 09 and the park can gain from the
installation of a nacelle-based lidar.
a. (Rotor speed dependent) wind vane calibration.
b. Determine if other turbines in the park can benefit from the installation of one nacelle-based lidar.
c. Match yaw misalignment angle, power and wind speed to estimate the power loss due to yaw misalignment.
IV. Estimate the blockage effect/compression zone in front of the turbine and
compare to models.
V. Determine under what conditions a nacelle-based lidar is financially
feasible.