Wind Turbine Derating Settings

Under certain circumstances a wind turbine may be derated, meaning its maximum power output gets limited to something less than its nameplate capacity. Derating logic may account for several variables including elevation, extreme temperatures, turbulence, shear, and veer. Windographer's derating logic accounts for the first two: elevation and temperature.

In Windographer, the derating settings consist of one or more more curves of maximum power output versus temperature, where each curve corresponds to an elevation. Windographer uses the maximum power curve as an upper limit to the power output of the turbine, meaning it sets the turbine power output in a particular time step to the lesser of that predicted by the power curve and that predicted by the derating curve.

The curves shown in the screenshot below, for example, indicate that:

At elevations below 500m, the turbine's maximum power output is 3000 kW at temperatures down to -15°C, dropping to 2500 kW at -22°C and then to only 1000 kW at -25°C. At the other end of the temperature scale, the maximum power stays at 3000 kW up to 25°C, then drops 2500 kW at 30°C, and then to 1000 kW at 35°C. (Windographer will assume that the turbine shuts down at more extreme temperatures.)
At elevations above 500m and below 1000m, the maximum power output decreases slightly to 2850 kW in the moderate temperature range, with similar low- and high-temperature derating beginning at slightly less extreme temperatures.
For elevations above 1000m and below 1500m, the maximum power output in the moderate temperature range falls to 2400 kW, and the moderate temperature range shrinks further.
For elevations above 1500m, the maximum power output in the moderate temperature range falls to 2000 kW, and the moderate temperature range shrinks again.

Tip: Windographer will assume that the turbine produces no power outside the temperature range that you specify in the derating curve.

You can enter the derating settings in the Edit Wind Turbine window, and in the Wind Turbine Output window you can indicate whether you want to apply them.