WindPack 1.5MW power coefficient

dear all
i want to control WindPack 1.5MW turbine for absorbing maximum energy from wind and for my simulation, i need power coefficient as a function of tip speed ratio and pitch angle.so i use WTPERF for obtaining power coefficient these data has been attached below.

i think there is a conflict with these data. as i know,the maximum power coefficient occur in blade pitch angle zero but
the maximum power coefficient happens in pitch angle 3. what is wrong with these calculation?
i will be so grate full for your answer as soon as possible.
best regards
wp baseline input file.txt (5.58 KB)
wp baseline .txt (326 KB)

Dear Farshad,

I have not looked at the files you attached, but–as discussed on the following forum topic and reference report: http://forums.nrel.gov/t/cp-power-coefficient-of-windpact-1-5-mw-turbine/790/7 --the rotor for the WindPACT 1.5-MW baseline wind turbine was designed for a maximum power coefficient (Cpmax) of 0.50 at an optimal tip-speed ratio (TSR) of 7.0 and an optimal blade-pitch angle (thetap) of 2.6 degrees.

Best regards,

dear jason
thank you very much for your answer. i will be so grateful if you confirm that these data are logical and can i use them for my control purpose?
best regards

Dear Farshad,

I’m sorry, but what data are you asking me to review? If you’re data using WT_Perf matches the values I reported in my prior post, that should give you confidence that you model is good.

Best regards,

Dear Jonkman,

I’m quite new at using FAST v8.16. Now on i’m testing the WindPack 1.5MW for control purposes. I’ve been traying to obtain the Cp-Lambda-betha curve but i’m not sure if i did it right. Here i present the steps i followed:

Servodyn:

     0 Pcmode
     0 VsCntrl
     2 GenModel(thevenin)

Elastodyn
Only GenDOF active

      0  BlPitch(1)  - Blade 1 initial pitch (degrees)
      0  BlPitch(2)  - Blade 2 initial pitch (degrees)
      0  BlPitch(3)  - Blade 3 initial pitch (degrees)
      0   RotSpeed

Attached you can find the wind profile used and the Cp-Lambda-Betha graph i got with this configuration. I had to change manually the pitch angle for each simulation.wind_profile.png

is this the correct procedure?
should i follow a different procedure?

I appreciate your help.

Best regards,

Dear Hernan,

I’m a bit concerned about two things in your approach:
*Instead allowing the rotor speed to vary based on the Thevenin model, I would suggest using a constant generator speed by disabling GenDOF.
*Instead of linearly ramping the wind speed, I would suggest stepping the wind speed from 5 to 15 m/s e.g. in steps of 1 m/s and record the steady-state Cp before the next step. There is likely a delay/dynamics between the input wind speed and output power, so, linearly ramping the wind speed may not give you desired effect.

Best regards,

Hello Mr. Jonkman,

Thanks for your quick reply. I just test the first step you mentioned (disabling GenDOF). This is what did:

  • Set initial or fix rotor speed equal to 5 rpm.
  • Use a Step wind of 5 m/s.

Once made this steps, i realize that the steady-state value of Cp varies depending on which DOF’s are activated. To clarify what i say, please see the figure shown below

As you can see, i ran the follow tests:

a) Drivetrain (DTT)/Yaw DOF (red line)
b) Drivetrain DOF (blue line)
c) Yaw DOF (magenta line)
d) No DOF active (black line)

We can see that a) and c) have the same behavior. On the other hand, b) and d) have a similar behavior.

My question is: what is the correct approach?

Best regards,

Dear Hernan,

It looks like the nacelle-yaw DOF is influencing your solution. I’m surprised that enabling the yaw increases the Cp. How are you calculating Cp? Do you have active yaw control? Have you set appropriate nacelle-yaw spring and damping or are you modeling free yaw? Are you simulating with a yaw error such that when you enable the yaw DOF the yaw is error is being reduced?

Best regards,

Dear Mr. Jonkman,

Please follow below the answers to your questions:

  • I get Cp from RtAeroCp variable computed by FAST

  • Yaw control is disabled

  • It seems that i’ve been simulating free yaw, but i’m not so sure about it. Here are the configured parameters already set for Yaw:

    [b] ELASTODYN[/b]
     0   NacYaw      - Initial or fixed nacelle-yaw angle (degrees)
     0   YawBrMass   - Yaw bearing mass (kg)
    
     [b]SERVODYN[/b]
      0     YCMode       - Yaw control mode {0: none, 3: user-defined from routine UserYawCont, 4: user-defined from Simulink/Labview, 5: user-defined 
                                 from Bladed-style DLL} (switch)
    

9999.9 TYCOn - Time to enable active yaw control (s) [unused when YCMode=0]
0 YawNeut - Neutral yaw position–yaw spring force is zero at this yaw (degrees)
0 YawSpr - Nacelle-yaw spring constant (N-m/rad)
0 YawDamp - Nacelle-yaw damping constant (N-m/(rad/s))
9999.9 TYawManS - Time to start override yaw maneuver and end standard yaw control (s)
2 YawManRat - Yaw maneuver rate (in absolute value) (deg/s)
0 NacYawF - Final yaw angle for override yaw maneuvers (degrees)

Hope this information helps to clarify the problem.

Best regards,

Dear Hernan,

Your settings look fine, but I’m not sure why you are simulating free yaw. I suggest that you disable the nacelle-yaw DOF (YawDOF = False).

Best regards,

Dear Mr. Jonkman,

Thanks again for your quick response. I’ve made an analysis varying the fix RotSpeed for YAWDOF case and DriveTrain (DTTr) case. This analysis yields that for low RotSpeeds the response of YawDOF influence the result, and if RotSpeed is increased, this influence seems to disappear. Well this is my approach, i’ll be thankful to know your opinion of this. Please find below the graphs for corresponding cases. I use 5 m/s wind step for all cases.
DTTrDOF_variable_RtSpeed.jpg

Best regards,

Dear Hernan,

I’m sorry, but I’m not sure I can comment as to why you are seeing an influence of the YawDOF on Cp for low rotor speeds, but not high. I suggest that you look at other outputs to understand what is going on.

Best regards,

Dear Mr. Jonkman,

I’ve made the tests as you suggested. Below is shown the Cp-lambda-Betha graph obtained from this test.

[attachment=0]cp_L_b.jpg[/attachment]

In order to fix rotor velocity, i disabled GenDof and kept enabled only DrTrDOF. Then i ran one single test for every pitch angle, aplying a Step wind input that varies from 5 m/s to 18 m/s in steps of 1 m/s.

Hope this be the approach you were expecting to see.

Best regards,

Dear Hernan,

I’m not able to see your graph, but your approach sounds OK. Please note that it is probably not useful to enable the DrTrDOF if you’ve disabled the GenDOF. (The natural frequency of the drivetrain-torsion DOF will be effected by disabling the generator DOF.)

Best regards,

Dear Jonkman,

An apologize about ths graph. Here is attached again below.

As you mentioned, i noticed that the behavior having DrTrDOF is quite different that when is disabled, but not so. I’ll make tests with the approach you suggest.

Best regards,

Dear Hernan,

Your approach sounds, and your results look, reasonable to me. But I’m not sure why your results are close, but do not exactly match the values reported above i.e. the rotor for the WindPACT 1.5-MW baseline wind turbine was designed for a maximum power coefficient (Cpmax) of 0.50 at an optimal tip-speed ratio (TSR) of 7.0 and an optimal blade-pitch angle (thetap) of 2.6 degrees. I have not run a similar analysis myself to confirm.

Best regards,

Dear Jonkman,

Actually, i’ve been wondering about the same matter but don’t know what is the root cause of this inaccuarate results. I’ll keep working and testing till get a closer approach. On the other hand, you have been very kind in help me out with this problem. Thanks a lot for your help Mr. Jonkman.

Best regards.