windtest kaiser-wilhelm-koog gmbh ewec 2007 session dt2 slide no. 1 comparison of the zephir...

WINDTESTKaiser-Wilhelm-Koog GmbH

EWEC 2007 Session DT2 Slide No. 1

Comparison of the ZephIR Wind-LiDAR to Classical Cup MeasurementsOn- and Offshore

Detlef Kindler WINDTEST Kaiser-Wilhelm-Koog GmbH

Andy Oldroyd Oldbaum Services Ltd.

EWEC 2007, Milan, Italy

“Advances in measuring methods”

Technical Track - Session DT2, 10 Mai 2007

supported by: EU-Project DOWNVInD - Partners

Title



• Motivation

• Onshore and Offshore Assesment Campaign 5M met.mast site, Brunsbüttel Offshore platform FINO-1, Germany

• Assessment Results Availability Data quality

• Wind Speed Profiles

• Turbulence Comparisons

• Summary

Outline



Remote Sensing (LiDAR) as primary wind resource monitoring method for Beatrice Windfarm Demonstrator Project

• Assessment of capabilities of the ZephIR Wind LiDAR

• Suitability for offshore purposes

Motivation

5M Offshore



Acceptance Criteria

Acceptance criteria for the ZephIR being used

as the primary wind monitioring method

on the Beatrice Alpha platform:

Availability: > 95 % (system & data)

Data quality: wind speed relative to cups (4 to 16 m/s)

linear regression through origin

Y = mx + b (i.e. with b==0)

0.97 < m < 1

R2 > 0.95



5M Onshore Test

4.0 m

Thiesfirst class

RisoeSonic

Windrichtung(Thies)

Temperatur(Thies)

Luftdruck(Thies)

Thiesfirst class

Thiesfirst class

sonic

Thiesfirst class

Temperatur(Thies)

Niederschlag

120 m

90 m

60 m

• 3 month campaign: 30 Sep 2005 until 5 Jan 2006

• Fairly large distance to met.mast

• Complex surrounding: industrial plants, wind turbines

70 m



FINO-1 Offshore Test

ZephIR

• North Sea, 45 km North of German island Borkum

• Annual mean wind speed on 100 m: ~ 10 m/s

• Prevailing wind dir.: SW

• Mast top height: 103 m

• ZephIR height: 25 m

• 5 Month campaignMarch to July 2006

• ZephIR close to mast ( ~ 10 m)

• No disturbance by met.mast on LiDAR

103 m

81 m

61 m



Availability

Onshore – 5M Met.-Mast Site

Overall System Availability: 99.6 %

Overall Data Availability (10-Min.-Avg.): 95.2 %

Offshore – FINO 1 Platform

Overall System Availability: 100.0 %

Overall Data Availability (10-Min.-Avg.): 99.6 %



WS Regressions Onshore

Slope:m = 0.97

Regr. coefficient:R2 = 0.97

90mSlope:m = 0.95


120m



Height:103 (78) m

WS range:

2 to 23 m/s

Regression:

m = 0.97

R2 = 0.99

WS Comparison Offshore

Cup

LiD

AR



WS Regressions Offshore

81 (56) m

Slope:m = 0.97


61 (36) m

Slope:m = 0.98




WS Regression Results

Sector 125° to 255°CUP CUP CUP

1st Period 120 m 90 m 60 m

10-min-avg. values 3034 / /

Slope "m" 0.94 / /

Regr. Coeff "R2" 0.95 / /

2nd Period 120 m 90 m 60 m

10-min-avg. values 2532 1688 1577Slope "m" 0.95 0.97 0.99

Regr. Coeff "R2" 0.96 0.97 0.95

Onshore180° to 255°

Sectors15°-75°, 105°-165°, 195°-

255°, 295°-345°

CUP CUP CUP

1st Period 103 (78) m 81 (56) m 61 (36) m

10-min-avg. values 1965 / /

Slope "m" 0.97 / /

Regr. Coeff "R2" 0.99 / /

2nd Period 103 (78) m 81 (56) m 61 (36) m

10-min-avg. values 6005 2589 2749

Slope "m" 0.98 0,97 0,98

Regr. Coeff "R2" 0.99 0.99 1,00

Offshore30° to 90° and 180° to 240°



WS Weibull Distribution

Cup LiDAR



Assessment Summary

• Good performance onshore despite terrain complexity ZephIR passed acceptance

• Offshore test FINO-1, similar environment as on Beatrice better correlation offshore than onshore

• Main result WS deviation from Cups < 3% Availability close to 100% (NO weather dependence) good handling, easy to install

• System passed acceptance onshore and offshore installation on Beatrice in Nov. 2006 stand-alone operation for wind monitoring,

good performance since

Note: 1st Beatrice 5M wind turbine connected since last Tue, 8th May 2007



WS Profiles

Wind Speed Profiles – Vertical Sampling:

Cup: point measurement

LiDAR: “average” over vertical range change of probing length with height 2

1( )

s

Ls

L s

20 40 60 80 100 120 140 160 180 200 220

Range (m)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

Sen

siti

vity

(re

l. t

o p

eak)

Altitude L

40m 2.5 m

60m 6 m

100m 16 m

200m 65 m

Source: RISOE



WS Profiles Offshore



WS Turbulence

Wind Speed Turbulence (10 minute averaging)

TRB = WS-STD / WS-Mean [%]

Sampling Cup: 1 Hz

600 values

Sampling LiDAR: 3 sec for individual height scan

5 consecutive heights

max. 40 values



WS Standard Deviation

Onshore Offshore



Turbulence vs. WS

Onshore Offshore



Turbulence WS Binned

Onshore Offshore



Turbulence

Differences in mast measurements

• Cup type Thies-1st-Class (On-), Vector (Offshore)

• STD calculation1Hz, 600 values, 10 Min.-STD1Hz, 60 values, 1 Min.STD 10 Min.STD (according to IEC)

Other differences onshore vs. offshore

• Terrain, obstacles

• Surface roughness

• Atmospheric stability

impact on dominant turbulence length scales

Character of volume measuring technique more pronounced onshore …



Overall Summary / Outlook

Assessment campaign: good availability and data quality onshore & offshore

Absolute wind speed accuracy is close to that of cups (with high quality calibrations)

WS profiles: good resemblance to cup / met.mast results

ZephIR turbulence measures compare to cup turbulence measures onshore and offshore, differently …?

Outlook

• More operational experiences are needed e.g. complex terrain applications

• Reproducibility device to device needs to be proven

• Best practice application procedures – testing / calibration

• Work towards standard acceptance / incorporation (e.g. IEC)



Thanks

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