EWEC 2006 IEA ANNEX XXI SPECIAL SESSION

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EWEC 2006 IEA ANNEX XXI SPECIAL SESSION
Assessment of structural dynamics for model
validation of induction generator-based wind
turbines
Olimpo Anaya-Lara, G. Ramtharan Ervin Bossanyi
and Nick Jenkins
IEA Annex XXI
Dynamic Models of Wind Farms for Power System
Studies
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OBJECTIVES

• Suggest which representation of the rotor
  structural dynamics is more appropriate for a
  particular study to ensure the correct validation
  of dynamic models of Fixed-Speed Induction
  Generator (FSIG) and Doubly-Fed Induction
  Generator (DFIG) wind turbines

• Develop FSIG and DFIG performance assessment
  during electrical transient such as three-phase
  faults (voltage dip) and network frequency
  variations

• Conduct studies in GH Bladed, which offers a
  suitable common platform with highly developed
  mechanical/electrical systems of FSIGs and DFIGs

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Rotor structural dynamics
Blade bending motions
In-plane blade bending
Out-of-plane blade bending
Flexible structure of a wind turbine rotor
As rotor size increases blade flexibiities
becomes significant and need to be represented
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Natural frequency of vibration
Low-speed shaft torque response (and harmonic
spectrum) with full rotor structural dynamics
during a 50 voltage sag (300 kW FSIG-based wind
turbine)

• Single-mass model neglects blade and shaft
  flexibility
• Typical two-mass model only considers shaft
  flexibility
• Full model in Bladed Complete representation of
  rotor structural dynamics (shaft and blade
  flexibilities)

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Assessment during a three-phase fault
300kW FSIG during a three phase fault (80
voltage drop, 20 retained voltage)
2MW DFIG during a three phase fault (85 voltage
drop, 15 retained voltage)
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Assessment during frequency variation
Applied frequency variation at the terminal of
the generators
300kW FSIG-based wind farm
2MW DFIG-based wind farm
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Conclusion and recommendations

• Rotor structural dynamics can influence the wind
  turbine response during electrical faults. Hence,
  for fault studies a model of the structural
  dynamics that includes both shaft and blades
  flexibilities may be more appropriate.

• Rotor structural dynamics have little effect on
  wind turbine performance in the event of loss of
  generation (frequency variations), therefore a
  simple single-mass model representation of the
  rotor structural dynamics may be appropriate for
  this type of studies