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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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Introduction

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Applications

1. Power curve2. Yaw misalignment3. Blockage effect

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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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Working principle

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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

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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

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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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3. Blockage effect

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3. Blockage effect

Good fit with theory (average and filtered)

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Financial feasibility

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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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The future

• Power curve measurement• Feed-forward control• R&D

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Questions

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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.

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Power and yaw misalignment

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Yaw misalignment and RPM/V