# Four boundary points of wind speed region division of 5MW base-land wind turbine

Dear Jason,

I want to know the four boundary points of wind speed region division of 5MW base-land wind turbine and I calculated it by myself.

The first point to between region1 and 1.5:the generator speed is 671rpm,so the rator speed is 670/97=6.9072rpm(about 0.7233rad/s) ,so at this point the wind speed is :0.7244*63/7.55=6.0357m/s (63 is the value of radus,7.55 is optimal tip-speed ratio).
I used the same way to get the value of the next two points:7.8464m/s and 10.4675m/s.Is this right?

Because i found the the value of a is smaller than b,but the width of b looks like biger a in the picture.I think there is something wrong about the value i get.(the value of a is 0.4,cut_out speed 11.4-11=0.4,b=10.4675-10=0.4675)

Dear Kayiu,

Your equation for calculating wind speed from the optimal tip-speed ratio can only be applied in Region 2; in other control regions, the TSR is not optimal. And please note that the baseline controller for the NREL 5-MW wind turbine does not make use of wind speed in its calculations.

Regardless, the transition wind speeds in the plot you are referring to were estimated visually as follows:
Region 1 to 1.5: 3 m/s
Region 1.5 to 2: 7.8 m/s
Region 2 to 2.5: 10.3 m/s
Region 2.5 to 3: 11.4 m/s

Best regards,

Dear Jason,

Thank you for your answer. It really helps a lot.I know the baseline controller for the NREL 5-MW wind turbine does not make use of wind speed in its calculations bacause the controller only need the value ofthe GenSpeed.the reason that I want to calculate these value is i want to know the wind speed suitalbe for NREL 5MW land-base wind turbine in region 2.Thank you for your patient reply again!

Dear Jason,
I am using the 3rd wind type(binary TurbSim FF),I want to know the wind speed in the above picture (such as 7.8-10.3m/s in region 2)in FAST v8.16 means Wind1VelX or RtVAvgxh?.Actually I want to design another Torque control for region 2,so I want to know this.

Dear Kaiyu.Fang,

The above figure was generated by using distinct simulations at each wind speed, using unique steady uniform wind conditions without shear (WindType = 1) for each simulation. So, the value of Wind1VelX would equal the prescribed wind speed.

Best regards,