Wind turbine class

[FINN]

Hello,
I have a question about the turbulence intensity and wind turbine class.
There are four wind turbine classes, A+, A, B, and C, from the IEC 61400-1 Ed.4, and we can calculate with WAT.
When I make a turbulence intensity graph with WAT, there are three straight-line graphs: mean, mean+StDev, and 90%.
Which line graphs should fit to wind turbine class?

[Morten]

The IEC standard asks us to compare the TI 90% level with the NTM model for the turbulence category (A+/A/B/C) of the turbine class. We only need to make this comparison in the wind speed range indicated the WAT effective TI plot.