is pitch control decided by power output or wind speed

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Yanda.Jiang
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is pitch control decided by power output or wind speed

Postby Yanda.Jiang » Fri Dec 27, 2019 10:13 pm

Hi guys,

When we talk about pitch control, we assume only if wind speed is larger than rated wind speed then mechanical power output could be larger than rated power output.
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However, considering wind speed is measured at hub height and wind speed at top and bottom of blade differ in direction and speed, wind power actually is much more complicated than formula 1/2*rho*area*v^3. I am wondering if it is possible when wind speed is still smaller than rated speed, the power output is already larger than rated power output. If so, then this might generate electrical power above limit value, which will harm generator. Under this condition, should pitch control still be decided by wind speed or by power output? Many thx in advance for your response.



Sincerely,
Yanda

Jason.Jonkman
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Re: is pitch control decided by power output or wind speed

Postby Jason.Jonkman » Sat Dec 28, 2019 8:40 am

Dear Yanda,

It is rare for the pitch controller to use a direct wind speed measurement in its feedback loop. Using the generator speed and/or electrical power is more common. The wind at hub height does not determine the control region.

Best regards,
Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

Yanda.Jiang
Posts: 16
Joined: Sun Mar 10, 2019 7:44 pm
Organization: Iowa state university
Location: United States

Re: is pitch control decided by power output or wind speed

Postby Yanda.Jiang » Sat Dec 28, 2019 9:09 am

Jason.Jonkman wrote:Dear Yanda,

It is rare for the pitch controller to use a direct wind speed measurement in its feedback loop. Using the generator speed and/or electrical power is more common. The wind at hub height does not determine the control region.

Best regards,


Thx, Jason. That makes sense. So the ideal power curve of wind turbine is only used to evaluate system condition of large scale renewable integration, right?

Jason.Jonkman
Posts: 5082
Joined: Thu Nov 03, 2005 4:38 pm
Location: Boulder, CO
Contact:

Re: is pitch control decided by power output or wind speed

Postby Jason.Jonkman » Sat Dec 28, 2019 10:06 am

Dear Yanda,

There are multiple uses for a power curve, but what you state is one of them. The power curve you show is really an averaged quantity.

Best regards,
Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

Yanda.Jiang
Posts: 16
Joined: Sun Mar 10, 2019 7:44 pm
Organization: Iowa state university
Location: United States

Re: is pitch control decided by power output or wind speed

Postby Yanda.Jiang » Sat Dec 28, 2019 10:13 am

Jason.Jonkman wrote:Dear Yanda,

There are multiple uses for a power curve, but what you state is one of them. The power curve you show is really an averaged quantity.

Best regards,


Thx, Jason. I appreciate your help on weekends.


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