Presentation by René Cattin, Meteotest at Winterwind 2012. "Ice throw reloaded – studies at Guetsch and St. Brais"

1. Ice throw studies
Gütsch and St. Brais
February 8, 2012
René Cattin

2. Icing in wind energy
Ice throw studies | Seite 2 | 2012-02-08

3. Icing in Switzerland
Wind map of Switzerland
Ice throw studies | Seite 3 | 2012-02-08

4. Icing in Switzerland
Icing map of Switzerland
Ice throw studies | Seite 4 | 2012-02-08

5. Gütsch
2‘300 m asl
Ice throw studies | Seite 5 | 2012-02-08

6. Gütsch
Does ice throw occur?
Enercon E-44
- How often?
- How far?
- How heavy?
- Where?
Enercon E-40
Enercon E-44
Ca. 7 days/year meteorological icing
Ca. 30 days/year instrumental icing
Ca. 150 days/year temperature below 0°C
Wind turbines equipped with blade heating
Ice throw studies | Seite 6 | 2012-02-08

7. Alpine Test Site Gütsch
COST Action 727: Atmospheric Icing on Structures
2005 to 2009
Ice throw studies | Seite 7 | 2012-02-08

8. Method
After each icing event, the area around the wind turbine
is inspected for ice throw.
All found ice fragments are recorded
- Distance
- Angle
- Size
- Weight
- Type of ice (rime, glaze, wet snow)
- Photo of ice fragment
Ice throw studies | Seite 8 | 2012-02-08

9. Method
Ice throw studies | Seite 9 | 2012-02-08

10. Method
Ice throw studies | Seite 10 | 2012-02-08

11. Methodik
• Not all events could be captured
• Inspection partly delayed
• Exact time of ice throw unknown
• No distinction between ice throw and
ice fall
Inspections during 4 winters (2005 bis 2009)
à 32 icing events recorded
à 228 ice fragments documented
à Also during summer
Ice throw studies | Seite 11 | 2012-02-08

12. Ice throw study Gütsch
Maximum distance: 92m (2.25 rotor diameter)
Maximum weight: 1.8 kg
Ice throw studies | Seite 12 | 2012-02-08

13. Ice throw study Gütsch
Ice throw studies | Seite 13 | 2012-02-08

14. Ice throw study Gütsch
Ice throw studies | Seite 14 | 2012-02-08

15. Ice throw study Gütsch
Icing
Föhn
à Risky areas seem to be dependant on
wind statistics under icing consitions
Ice throw studies | Seite 15 | 2012-02-08

16. Ice throw study Gütsch
Types of ice
Rime Glaze Wet snow
Ice throw studies | Seite 16 | 2012-02-08

17. Ice throw study Gütsch
Distance to wind turbine
50%
Rotor blade
Ice throw studies | Seite 17 | 2012-02-08

18. Ice throw study Gütsch
Angle relative to wind turbine
Ice throw studies | Seite 18 | 2012-02-08

19. Ice throw study Gütsch
Resulta
te
Ice throw studies | Seite 19 | 2012-02-08

20. Conclusions
• Ice throw occurs
• Wind conditions during icing event define risk areas
• Ice throw when blade is moving downwards?
• 50% of ice fragments found under rotor blade
• Heavy ice fragments (> 600 g) under rotor blade
• Ice throw also during summer time
à Übertragbarkeit der Resultate auf grössere WEA??
Ice throw studies | Seite 20 | 2012-02-08

21. Counter measures
• Routing of winter walkway was changes
• Warning signs were installed
Ice throw studies | Seite 21 | 2012-02-08

22. Conclusions
Further study during winter 2011/12
2 Enercon E-82
Hub height 78 m
Enercon blade heating
St. Brais
1‘100 m asl
No real icing events so far
Ice throw studies | Seite 22 | 2012-02-08

23. Ice throw model SWIM
• Simple Wind turbine Icethrow Model
Ice throw studies | Seite 23 | 2012-02-08

24. Ice throw model SWIM
• Simple Wind turbine Icethrow Model
Ice throw studies | Seite 24 | 2012-02-08

25. Ice throw model SWIM
• Simple Wind turbine Icethrow Model
Ice throw studies | Seite 25 | 2012-02-08

26. Thank you…
METEOTEST …for your attention
Fabrikstrasse 14
CH-3012 Bern
www.meteotest.ch
Ice throw studies | Seite 26 | 2012-02-08