Technology
IEEE PES
22 July 2008
JP Lyons - Novus Energy Partners
Bob Thresher – NREL Wind Tech Center
Mike Robinson – NREL Wind Tech Center
Paul Veers – Sandia National Labs
Modern Wind Turbines
Electrical Pitch
Drives
GE 1.5sl
• 1.5 MW
• 77 M Rotor Diameter
• 50-100 M Tower
Doubly-Fed
Generator
• 98% Availability
• Speed 10-20 RPM
Main Shaft &
Bearing
• Variable Pitch
Gearbox
Epoxy-Glass
Composite Blades
Transformer &
Electrical
Power Electronic
Converter
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Vestas V100-2.75
Land Based Technology
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80-100m tapered cylindrical steel towers
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3 stage gearbox
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Distributed component drivetrain
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Clipper 2.5-93
1.5 -3.0 MW upwind configuration
Full span pitch control
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200+MW Windfarms
Capacity Factor = (Annual Yield MWHrs)/(24*365*Power Rating)
Performance
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97+% Availability
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40+% CF at IEC-II 8.5 m/s
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CF% +10 pts in last 5 yrs
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~65 kWhr/kg tower top mass
GE 2.5xl
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Blades
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July, 2008
Wind Energy Conversion
Rotor power: P = 1/2 cp ρAvw3 cp - rotor power coefficient ρ - air density
A - rotor swept area
Ideal cp = 0.593 (Betz factor) where V2 = 1/3 V1 (wind velocity slows by 2/3)
Tip speed ratio: λ = vt / vw cp = f(λ)
“Windturbines: Fundamentals, Technologies, Application and Economics”, Erich Hau, ISBN: 3540570640; (April 30, 2000)
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Wind
Turbine
Dynamics
Periodic Forces Excite Mechanical System
• dominated by blade passing frequency (BP)
• 3P - wind shear, yaw error, tower shadow
• 1P - rotor unbalance gravity
• P - rotational frequency
Turbine Natural Frequencies
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Tower bending modes
Blade flap bending mode
Blade flutter & torsional modes
Yaw system torsional mode
Drive train torsional oscillation
“Windturbines: Fundamentals, Technologies, Application and Economics”, Erich Hau, ISBN: 3540570640; (April 30, 2000)
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