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Ice Induced Vibration Measurements On MW scale wind turbines Presented by: Ville Lehtomäki, VTT Matthew Wadham-Gagnon, TCE 2013-02-12 WinterWind 2013

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Page 1: Lehtomäki ville

Ice Induced Vibration Measurements

On MW scale wind turbines

Presented by:

Ville Lehtomäki, VTT

Matthew Wadham-Gagnon, TCE

2013-02-12

WinterWind 2013

Page 2: Lehtomäki ville

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Co-authors

V. Lehtomäki, VTT, Finland

S. Rissanen, VTT, Finland

T. Karlsson, VTT , Finland

M. Wadham-Gagnon, TCE, QC, Canada

D. Bolduc, TCE , QC, Canada

B. Boucher, TCE , QC, Canada

E. Bechoefer, NRG, VT, USA

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Content

• Motivation

• Case Canada • Infrastructure

• Icing Event no1: glaze

• Icing Event no2: rime

• Case Finland • Site & measurement system description

• Ice detection: Finding icing cases from various databases

• Icing Event no3: light rime

• Loads on blades & tower

• Conclusions

• Future work

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Motivation

• Currently 60 GW of wind energy in cold and icing climate (CIC) [3]

• Global wind energy in CIC ≈ 3 x global offshore! [5]

• NREL estimate: 50% of US wind fleet in CIC by 2030 [4]

• Problem of production losses caused by iced blades “well known”.

• BUT no clear idea, how turbine lifetime is affected by iced

blades.

• Thesis: Are premature failure of main components e.g.

gearboxes & towers resulting to “hidden” financial penalties

BIGGER than production losses?

• ULTIMATE GOAL: Increase knowledge & improve wind energy

reliability in CIC.

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Work presented here

• Preliminary analysis to feed in to:

• IcedBlades – Research consortium with European partners to

assess the effect of ice induced vibration on fatigue loads

• TC88 Cold Climate Sub Committee to include ice load case in

next edition of IEC61400-1

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Main questions to be answered:

1. Does icing of blades increase vibrations and loads?

2. Which turbine components are most affected?

3. What causes increased loads?

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Case Canada

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TCE infrastructure location

Over 900MW in operation

TCE R&D wind farm

8

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TCE R&D Wind Farm

www.eolien.qc.ca

• Two 2.05 MW Repower MM92 wind turbines

• Located in Riviere-au-Renard, Québec, Canada

• Icing & complex terrain

• Commissionned in March 2010

• Research, development and technology transfer projects involving northern climates and complex terrain.

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TCE 126m Met Mast

Compliant with

CSA-S37-01

(DLC: 40 mm of ice

and 57 m/s)

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Infrastructure Topographic Layout

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Health Monitoring System

• Text

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• Measurement Campaign running since December 2011

• 2-axis sensor to measure nacelle accelerations

• Nacelle X (fore and aft) & Nacelle Y (side to side)

13

Vibration Data

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• Measurement Campaign running since December 2011

• 2-axis sensor to measure nacelle accelerations

• Nacelle X (fore and aft) & Nacelle Y (side to side)

• FFT1 = Normalised magnitude of first tower eigenvalue from FFT

• FFT1 data Normalised with respect to wind speed (WS) and turbulence

intensity (TI) BIN matrix as follows:

14

Vibration Data

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Vibration Data

0

0.2

0.4

0.6

0.8

1

1.2

1.4

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• Possibility of ice induced vibration when y-axis value exceeds 1

16

Vibration Data

0

0.2

0.4

0.6

0.8

1

1.2

1.4

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• Not all values that exceed 1 are due to icing

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Vibration Data

0

0.2

0.4

0.6

0.8

1

1.2

1.4

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Icing Event example 1 (IE1) - Glaze

~5mm of glaze 2012-01-16

2012-01-14

• Freezing Rain

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IE1 – Meteorological Icing

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

Event type Method Duration

Meteorological Icing Ice sensor ~ 6 hours (15 hours)

Meteorological icing

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IE1 – Instrumental Icing

Event type Method Duration

Meteorological Icing Ice sensor ~ 6 hours (15 hours)

Instrumental Icing Heat/Unheat Anemometers ~ 65 hours

0

5

10

15

20

25

WS

(m/s

)

WS1 WS2

Meteorological icing Instr. Icing

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IE1 – Production Loss

Event type Method Duration

Meteorological Icing Ice sensor ~ 6 hours (15 hours)

Instrumental Icing Heat/Unheat Anemometers ~ 65 hours

Production loss Actual vs expected power ~ (1.5 hours)

0

500

1 000

1 500

2 000

2 500

Po

we

r (k

W)

Power CPC

Meteorological icing Instr. Icing Prod. Loss

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0

1

2

3

4

5

6

22

IE1 – Nacelle Y

Event type Method Duration

Meteorological Icing Ice sensor ~ 6 hours (15 hours)

Instrumental Icing Heat/Unheat Anemometers ~ 65 hours

Production loss Actual vs expected power ~ 1.5 hours

Ice Induced Vibration Nacelle X and Y – FFT1 ice index ~ 5 hours (50 hours)

Meteorological icing Instr. Icing Prod. Loss Ice induced Vibration

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0

1

2

3

4

5

6

23

IE1 – Nacelle Y

Event type Method Duration

Meteorological Icing Ice sensor ~ 6 hours (15 hours)

Instrumental Icing Heat/Unheat Anemometers ~ 65 hours

Production loss Actual vs expected power ~ 1.5 hours

Ice Induced Vibration Nacelle X and Y – FFT1 ice index ~ 5 hours (50 hours)

Meteorological icing Instr. Icing Prod. Loss Ice induced Vibration

Ice Shed?

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0

0.5

1

1.5

2

2.5

3

3.5

4

24

IE1 – Nacelle X

Event type Method Duration

Meteorological Icing Ice sensor ~ 6 hours (15 hours)

Instrumental Icing Heat/Unheat Anemometers ~ 65 hours

Production loss Actual vs expected power ~ 1.5 hours

Ice Induced Vibration Nacelle X and Y – FFT1 ice index ~ 5 hours (50 hours)

Meteorological icing Instr. Icing Prod. Loss Ice induced Vibration

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Icing Event example 2 (IE2) - rime

Photos taken 2012/11/09 16:00

Estimated 15-20 cm of ice near tip

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IE2 – Meteorological Icing

0

25

50

75

100

125

150

-5

0

5

10

Clo

ud

He

igh

t (m

)

Tem

p (

oC

)

MMV2 78m T WEC1 Temp MMV2 11m Min CH

Event type Method Duration

Meteorological Icing Cloud Height & Temperature ~ 30 hours

Meteorological icing

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IE2 – Instrumental Icing

0

5

10

15

20

25

30

35

WS

(m/s

)

WEC1 WS cup WEC1 WS heat avg

Event type Method Duration

Meteorological Icing Cloud Height & Temperature ~ 30 hours

Instrumental Icing Heat/Unheat Anemometers ~ 60 hours

Meteorological icing Instr. Icing

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IE2 – Production Loss

Event type Method Duration

Meteorological Icing Cloud Height & Temperature ~ 30 hours

Instrumental Icing Heat/Unheat Anemometers ~ 60 hours

Production loss Actual vs expected power ~ 30 hours

0

500

1000

1500

2000

2500

Po

we

r (k

W)

WEC1 Power WEC1 CPC

Meteorological icing Instr. Icing Prod. Loss

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0

0.5

1

1.5

2

2.5

3

29

IE2 – Nacelle X

Event type Method Duration

Meteorological Icing Cloud Height & Temperature ~ 30 hours

Instrumental Icing Heat/Unheat Anemometers ~ 60 hours

Production loss Actual vs expected power ~ 30 hours

Ice Induced Vibration Nacelle X – FFT1 ~ 30 hours

Meteorological icing Instr. Icing Prod. Loss Ice induced Vibration

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0

0.2

0.4

0.6

0.8

1

1.2

1.4

30

IE2 – Nacelle Y

Event type Method Duration

Meteorological Icing Cloud Height & Temperature ~ 30 hours

Instrumental Icing Heat/Unheat Anemometers ~ 60 hours

Production loss Actual vs expected power ~ 30 hours

Ice Induced Vibration Nacelle X – FFT1 ~ 30 hours

Meteorological icing Instr. Icing Prod. Loss Ice induced Vibration

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Case Finland

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Case Finland

-Site & measurement system description-

• Site location: Southern Finland

• MW-scale turbine (near shore)

• Meas. acc. to IEC 61400-1-12 (power) &

-13 (loads)

• Measurement campaign: 9/2007-8/2009

• Load measurements at 50Hz

• Blade#1-2 root (flap&edge)

• Tower top (roll,pitch&yaw)

• Tower base (s2s&fa)

• Met mast

• Heated & unheated cup anemometer

• No dedicated ice detectors Bas

e: 3

0m

asl

Hu

b h

eigh

t: 1

00

m a

sl

Bla

de

tip

: 13

0m

asl

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Baseline values

• Before looking at Icing Event (IE) power production or loads, a

reference non-iced dataset is need as baseline values.

• Baseline values are then compared to IE values.

1. Calculate baseline (non-iced) values taking into account: • Wind speed [m/s]

• Turbulence intensity [%]

• Turbine status (power production)

• Wind sector (wake or terrain effects)

• Temperature (>0

C)

2. Calculate relative values for IE using formula (1)

• If relative = 1, then IE values = baseline values.

(1)

IEC 61400-13 &

IEC 61400-1-12

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Ice detection with multiple signals (9/2007-8/2009)

Icing Event no3

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Icing Event no3 (IE3): In-cloud light rime icing

Alarm hours

1+2: 19h

1+2 or 2+3: 19h

48h from start to finish with Ice Warning & cold cup anemo freezing.

Cold (unheated) anemo stops

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IE3: Blade & tower loads

Increase in tower fatigue loads

4% flap deviation between b2 & b3 result to aerodynamic imbalance of the rotor

80% threshold of baseline limits in ”grey tube”

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IE3: Blade & tower loads

Tower fore-aft fatigue DEL increased by 5..32%

Mean flap load decrease by 10…20% Tower fore-aft mean decreased by 15..45%

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Conclusions (1/3)

• More reliable ice detection achieved with multiple methods.

• For both rime icing cases analyzed, the duration of:

• Meteorological icing ≈ cloud base height & temperature* ≈

production loss ≈ above threshold tower vibration.

• Above threshold tower vibrations in:

• IE1 (glaze) for 50h

• IE2 (rime) for 30h

• IE3 (light rime) for 14h

• IE1 (glaze) led to significant increase in nacelle-X and -Y

vibrations

• IE2 (rime) led to significant increase in nacelle-X vibration but

NO apparent vibration in nacelle-Y

* www.WindPowerIcingAtlas.com, online soon

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Conclusions (2/3)

• In IE1-2, tower vibrations continue at increased levels even

when power production is returned to baseline levels.

• Mean blade & tower loads decrease during IE3

• Tower base fatigue loads increase in IE3

* www.WindPowerIcingAtlas.com, online soon

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1. Does icing of blades increase vibrations and loads?

• Yes, during IE1-3.

2. Which turbine components are most affected?

• Blade fatigue loads decrease, tower base

fatigue loads increase.

3. What causes increased loads?

• In IE3 (light rime), aerodynamic imbalance.

Conclusions (3/3)

-Main takeaways-

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• More icing events need to be analyzed in order to get a thorough statistical view on the long-term impacts.

• Analyse P2P, RMS and RPM data

• Analyse gearbox higher speed shafts

• Determine fatigue loads for other components

• Replicate icing events with multi body dynamics simulation (e.g. NREL FAST and FLEX5)

41

Future Work

Page 42: Lehtomäki ville

Thanks, Kiitos, Tack, Merci!

Åre, 9.2.2013

Page 43: Lehtomäki ville

Matthew Wadham-Gagnon, eng, M.eng

Project Lead

[email protected]

70, rue Bolduc, Gaspé (Québec) G4X 1G2

Canada

Tél. : +1 418 368-6162

Ville Lehtomäki, M.Sc. (Tech)

Research Scientist

[email protected]

Vuorimiehentie 5, Espoo, P.O. Box 1000, FI-02044 VTT Finland

Tél. : +358 40 176 3147

Finnish Funding Agency for Technology and Innovation

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References

[1] Lehtomäki, V. et al., IcedBlades - Modelling of ice accretion on rotor blades in a coupled

wind turbine tool, WinterWind 2012 conference, Skellefteå, Sweden

[2] IEC 61400-1:2005 ed3, Wind Turbines – Part 1: Design requirements, International

Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20,

Switzerland

[3] IEA WIND TASK 19, EXPERT GROUP STUDY ON RECOMMENDED PRACTICES: 13.

WIND ENERGY PROJECTS IN COLD CLIMATES, 1. EDITION 2011, Approved by the

Executive Committee of IEA Wind May 22, 2012.

[4] Baring-Gould, I. US Wind Market Overview, WinterWind 2011 conference

[5] Laakso, T. et al., IEA WIND TASK 19 WIND ENERGY IN COLD CLIMATES: Cold Climate

Challenges, EWEA 2011 side event, Brussels, Belgium