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Difference between revisions of "Wind Turbine Technology"

From energypedia
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=== Operation of Variable Speed Wind-Turbines<br>  ===
 
=== Operation of Variable Speed Wind-Turbines<br>  ===
  
Start up (with open breaker) if wind speed &gt; cut-in wi
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Start up (with open breaker) if wind speed &gt; cut-in wi  
  
 
[[Image:Typical power curves of wind turbines.jpg|frame|right|Typical power curves of wind turbines.jpg]]  
 
[[Image:Typical power curves of wind turbines.jpg|frame|right|Typical power curves of wind turbines.jpg]]  
  
nd speed<br>• Close breaker<br>
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nd speed<br>• Close breaker<br>  
  
 +
<br>
  
 +
<br>
  
 +
• Below rated wind-speed<br>– Maximum power coefficient (Max. Power Tracking)<br>
  
 +
<br>
  
• Below rated wind-speed<br>– Maximum power coefficient (Max. Power Tracking)<br>
+
<br>  
  
 +
– Evt: Speed Limitation<br>• Above rated wind-speed:<br>– P=Pr<br>ated (Limited by power electronics converter)<br>– Pitching
 +
 +
• Advantages of variable speed operation:<br>– Lower cut-in wind speeds<br>– Higher efficiency, especially at low wind speeds<br>– Lower power variations (compared to fixed speed turbines)<br>• Disadvantage: More expensive!<br>
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 +
<br>
  
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<br>
  
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== Generator concepts<br>  ==
  
 +
[[Image:Overview_Wind_generator_concepts.jpg|frame|center]]
  
– Evt: Speed Limitation<br>• Above rated wind-speed:<br>– P=Pr<br>ated (Limited by power electronics converter)<br>– Pitching
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=== Fixed Speed Induction Generator<br> ===
  
• Advantages of variable speed operation:<br>– Lower cut-in wind speeds<br>– Higher efficiency, especially at low wind speeds<br>– Lower power variations (compared to fixed speed turbines)<br>• Disadvantage: More expensive!<br>
+
[[Image:Fixed speed induction generator.jpg|frame|center|Fixed speed induction generator.jpg]]Only fix speed operation possible (stall control required)<br>• Reactive power compensation required<br>• No reactive power control capability. Additional devices required:<br>– TSCs (Thyristor switched capacitors)<br>– STATCOMs<br>• Risk of dynamic voltage collapse<br>GTZ Expert Workshop 2010: Grid and System Integration of Wind Energy, 22/23.11.2010, Berlin/Germany<br>y g p<br>– &gt; Typically, wind generators based on induction generators are asked to<br>disconnect in case of voltage dips<br>  
  
 +
=== Induction Generator with Variable Rotor Resistance<br>  ===
  
 +
[[Image:Induction Generator with Variable Rotor Resistance.jpg|frame|center|Induction Generator with Variable Rotor Resistance.jpg]]Simple concept for variable speed operation.<br>• Reactive power compensation required.<br>• No reactive power control capability. Additional devices required:<br>– TSCs (Thyristor switched capacitors)<br>– STATCOMs<br>• Limited LVRT capability. Dynamic voltage collapse problems have to<br>GTZ Expert Workshop 2010: Grid and System Integration of Wind Energy, 22/23.11.2010, Berlin/Germany<br>be mitigated by:<br>– Fast increase of rotor resistance during faults<br>– Additional reactive power compensation devices (typically TSCs)<br>
  
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=== <br>Doubly-Fed Induction Generator<br>  ===
  
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=== [[Image:Doubly-fed_induction_generator.jpg|frame|center]][[Image:Doubly_fed_induction_generatorf_Power_flow_over-_and_subsyncronous_speed.jpg|frame|center]]Generator with Fully Rated Converter<br> ===
  
== Generator concepts<br> ==
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=== [[Image:Generator_with_Fully_Rated_Converter_Kopie.jpg|frame|center]]Generator with fully rated converter and direct drive <br> ===
  
=== Fixed Speed Induction Generator<br> ===
+
<br>
  
[[Image:Fixed_speed_induction_generator.jpg|frame|center]]Only fix speed operation possible (stall control required)<br>• Reactive power compensation required<br>• No reactive power control capability. Additional devices required:<br>– TSCs (Thyristor switched capacitors)<br>– STATCOMs<br>• Risk of dynamic voltage collapse<br>GTZ Expert Workshop 2010: Grid and System Integration of Wind Energy, 22/23.11.2010, Berlin/Germany<br>y g p<br>– &gt; Typically, wind generators based on induction generators are asked to<br>disconnect in case of voltage dips<br>
+
[[Image:Generator_with_Fully_Rated_Converter_and_direct_drive.jpg|frame|center]]
  
=== Induction Generator with Variable Rotor Resistance<br> ===
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=== Directly Coupled Synchronous Generator with Variable Gear Box<br> ===
  
[[Image:Induction_Generator_with_Variable_Rotor_Resistance.jpg|frame|center]]Simple concept for variable speed operation.<br>• Reactive power compensation required.<br>• No reactive power control capability. Additional devices required:<br>– TSCs (Thyristor switched capacitors)<br>– STATCOMs<br>• Limited LVRT capability. Dynamic voltage collapse problems have to<br>GTZ Expert Workshop 2010: Grid and System Integration of Wind Energy, 22/23.11.2010, Berlin/Germany<br>be mitigated by:<br>– Fast increase of rotor resistance during faults<br>– Additional reactive power compensation devices (typically TSCs)<br><br>
+
[[Image:Directly_Coupled_Synchronous_Generator_with_Variable_Gear_Box.jpg|frame|center]]<br>

Revision as of 16:15, 12 July 2011

Wind turbine control concepts

Aerodynamics

Aerodynamics of a wind turbine blade
Stall

Wind turbine blade aerodynamics - stall control.jpg

Stall Control:
– Passive Stall:
Power of the wind turbine is limited by the aerodynamic characteristics
of the turbine.
– Active stall:
Power of the wind turbine is limited additionally by decreasing the pitch
angle (increasing the inflow angle ).

Pitch

Aerodynamics at a wind turbine blade during control through pitching

Pitch Control:
– Power of the wind turbine is limited by increasing the pitch angle
(decreasing the inflow angle )

Wind turbine operation

Operation of Fix Speed Wind Turbine (passive stall)

• Start up (with open breaker) if wind speed > cut-in wind speed
• Close breaker
• Operation at constant blade angle over the whole wind speed range
• In case of large wind speeds: Power limited by aerodynamic profile.


Operation of Variable Speed Wind-Turbines

Start up (with open breaker) if wind speed > cut-in wi

Typical power curves of wind turbines.jpg

nd speed
• Close breaker



• Below rated wind-speed
– Maximum power coefficient (Max. Power Tracking)



– Evt: Speed Limitation
• Above rated wind-speed:
– P=Pr
ated (Limited by power electronics converter)
– Pitching

• Advantages of variable speed operation:
– Lower cut-in wind speeds
– Higher efficiency, especially at low wind speeds
– Lower power variations (compared to fixed speed turbines)
• Disadvantage: More expensive!



Generator concepts

Overview Wind generator concepts.jpg

Fixed Speed Induction Generator

Fixed speed induction generator.jpg

Only fix speed operation possible (stall control required)
• Reactive power compensation required
• No reactive power control capability. Additional devices required:
– TSCs (Thyristor switched capacitors)
– STATCOMs
• Risk of dynamic voltage collapse
GTZ Expert Workshop 2010: Grid and System Integration of Wind Energy, 22/23.11.2010, Berlin/Germany
y g p
– > Typically, wind generators based on induction generators are asked to
disconnect in case of voltage dips

Induction Generator with Variable Rotor Resistance

Induction Generator with Variable Rotor Resistance.jpg

Simple concept for variable speed operation.
• Reactive power compensation required.
• No reactive power control capability. Additional devices required:
– TSCs (Thyristor switched capacitors)
– STATCOMs
• Limited LVRT capability. Dynamic voltage collapse problems have to
GTZ Expert Workshop 2010: Grid and System Integration of Wind Energy, 22/23.11.2010, Berlin/Germany
be mitigated by:
– Fast increase of rotor resistance during faults
– Additional reactive power compensation devices (typically TSCs)


Doubly-Fed Induction Generator

Doubly-fed induction generator.jpg
Doubly fed induction generatorf Power flow over- and subsyncronous speed.jpg
Generator with Fully Rated Converter

Generator with Fully Rated Converter Kopie.jpg
Generator with fully rated converter and direct drive


Generator with Fully Rated Converter and direct drive.jpg

Directly Coupled Synchronous Generator with Variable Gear Box

Directly Coupled Synchronous Generator with Variable Gear Box.jpg