Hi everyone,
I’m a PhD student. My research is effect of turbulence intensity on load of WT blade,
I also ran FAST code but I have some problems:
Thank you very much.
Sang.Le
Dear Sang.Le,
A negative value for GenPwr in FAST implies a motoring situation where the generator is causing the rotor to spin. Is motoring expected in your simulation?
I’m not sure I understand your second question. Are you asking what blade output channels are normally analyzed in a loads analysis or something else?
Best regards,
Dear Jason.Jonkman,
Thanks for your reply,
I’m calculating for WT 100kW and I want to know electricity produce from WT.
Therefore, is my result of WT a motor?
The second question is “If I choose blade output for loads analysis of blade, is it ok or not?”
and I want to deeply understand about loads analysis of blade, what should I focus on?
I’m also studying XFLR5 and somethings.
Thank you very much for your help.
Dear Sang.Le,
A motoring situation implies e.g. a generator-induced start-up event. Is this the simulation you are trying to run? The generator power should be positive during normal operation.
Loads analysis for blades typically involves running a series of time-domain simulations for the whole turbine system (rotor + nacelle + tower) across a range of operational, start-up/shut-down, parked/idling, and fault conditions. For each simulation, the blade loads (the two transverse bending moments at a minimum) at the blade root, and typically several other stations along the length of the blade are output, as well as blade-tip deflection for checking e.g. tower clearance. These time-series are post-processed to find the ultimate loads (highest load in e.g. 50 years) and fatigue loads (over e.g. the 20-yr lifetime). See the appropriate IEC design standards (e.g,. 61400-1 or 61400-2) for details on the process.
XFLR5 is not an NREL/DOE developed/supported tool, so, I doubt we’d be able to offer any guidance on that tool here.
Best regards,
Dear Jason,
Thank you very much for your help.
Your explanation was very helpful to me.
I want to change generator power to position. What can I change?
I will try to run FAST again and I’m going to analyse load of WT’s blade. I will ask you later.
Best regards
Sang.Le
Dear Sang,
I’m sorry, but I’m not sure I understand your question. What position do you want to output? The generator azimuth angle is not an output from FAST, but you can output the azimuth angle of the low-speed shaft on the generator- (LSSGagPxa) or rotor-side (LSSTipPxa) of the shaft.
Best regards,
Dear Jason,
Thank you very much for your answer,
I’m going to calculate again.
Best regard.
Dear Jason,
Please explain to me:
Assuming PCMode = 0, but I change BlPitch(1) = 0 and BlPitchF(1) = 20.
This mean “Is pitch angle change?”
So, I want to change yaw control and rotor speed in FAST. How can I changes?
If YCMode = 0, VSContrl = 0.
Best regards.
Dear Sang.Le,
FAST input PCMode determines how active control will be implemented e.g. through the Fortran subroutine PitchCntrl, through Simulink, or through a Bladed-style DLL. FAST input BlPitch is always the initial pitch angle. The override pitch maneuvers determined by TPitManS, BlPitchF, etc. override what the active controller is doing, regardless of the method selected. If you want to confirm that the pitch angle is responding as expected, include the blade pitch in the FAST output file and plot the time series.
I’m not sure I understand your other questions. But if you want to control yaw without an active yaw controller through YCMode, you can use the override yaw maneuvers instead. Control of the torque is possible through an active controller (via VSContrl) or a generator model (GenModel).
Best regards,
Dear Jason,
Thank you very much for your helpful information.
I want to calculate rpm of rotor of WT. How can i find calculated method?
Because I see that If Pitch angle (wind speed from 3-20 m/s) will have rpm of rotor respectively.
Please show to me.
Best regards.
Dear Sang.Le,
Again, I’m not really sure I know what you are asking. Please write clearer questions.
It sounds like you want to know how to calculate steady-state (or mean) values of rotor speed and pitch as a function of wind speed. For a given wind turbine with a given control system, you can do this by running a series of FAST simulations at a number of given, steady, and uniform wind speeds (with pitch and torque control enabled). Separate simulations can be run at each wind speed and each simulation should be run long enough to ensure that all transient behavior had died out, then record the steady-state values of rotor speed and pitch angle.
Best regards,
Dear Jason,
Thank you very much for your explanation.
I’m so sorry because my question was not clear. Luckily, your explanation is right for me.
The mean of your explanation is: I have to run separate simulations with conditions such as steady and uniform wind speed, no pitch control,
no yaw control to find out optimal values (steady-state values) of PtchPMzc1 and RotSpeed . But, input file of FAST, we have to enter the fixed value of RotSpeed.
So, How to know when we have optimal values of PtchPMzc1 and RotSpeed (based on what kind of output parameters) ? I understand slowly, please explain deeply to me.
Once more, I’m running FAST code with turbulence condition, but the results are not good
because the output values of PtchPMzc1 and RotSpeed are steady so it is not correct. I don’t know why?
But I think that values of PtchPMzc1 and RotSpeed should be unsteady in turbulence wind condition.
Please help me.
Best regards.
Dear Sang.Le,
Actually, you enter the initial rotor speed in FAST. If the generator and drivetrain DOFs are disabled, the initial rotor speed becomes the constant rotor speed used throughout the simulation.
If you’re trying to find optimal values of the blade-pitch and rotor speed, you should output e.g. the power coefficient (RotCp). To calculate the maximum (optimal) RotCp for a given rotor, you could run FAST with the torque and pitch controllers disabled (with the generator DOF disabled), and run a series of simulations at different fixed rotor speeds and pitch angles at a fixed wind speed (say 8 m/s) in order to sweep a range of tip-speed ratios (TSR) and pitch angles. The maximum RotCp should be obvious by viewing the resulting surface of RotCp versus TSR and pitch.
You should only run a simulation with turbulence with a proper operational torque and pitch control system enabled (with the generator DOF enabled).
Best regards,
Dear Jason,
Thank you very much for your help.
I understood. I will practise FAST code.
I focus on load analysis of blade. I will ask you later.
Best regards.
Dear Jason,
I want to make Blade.dat for wind turbine. Please show me.
Thank you very much for your comments.
Best regards.
Dear Sang.Le,
Instead of creating a blade data file from scratch, start by editing one of the example models provided in the CertTest folder of the FAST archive. A detailed description of each input can be found in the FAST User’s Guide.
Best regards,
Dear Jason,
Please help me
I’m running FAST code with some conditions as followed:
I assumed:
TPitManS(1) = 11; TPitManE(1) = 35; TPitManS(2) = 11; TPitManE(2) = 35; TPitManS(3) = 11; TPitManE(3) = 35
BlPitch(1) = 0; BlPitchF(1) = 25; BlPitch(2) = 0; BlPitchF(2) = 25; BlPitch(3) = 0; BlPitchF(3) = 25
My question is how is period of time (TPitManS and TPitManE) optimal for my simulation?
Best regards.
Dear Sang.Le,
I’m not sure what you mean by “optimal”. Pitch ramps are normally based on actuator limits.
Best regards,
Dear Jason,
Thank you very much for your explain.
I have to study more and ask you later.
Best regards.
Sang.Le
Dear Jason,
Thank you very much for your help.
I’m running FAST code with turbulent wind condition (A, B, C and specify TI = 8%).
How ever, the P-V graph don’t show expected power curve.
The power of A turbulent wind condition is the highest.
Please show my mistake in FAST input file.
Best regards.
Sang.Le