How do wind turbines operate?
Wind turbines are sophisticated machines with computer controls.
A typical operating sequence is as follows:
- when the wind speed reaches the cut-in speed of the turbine (usually around 4 metres per second), the turbine blades will spin up to operating speed, usually around 14 to 29 rpm (varies by turbine model), and start generating electricity
- as the wind speed increases, the generator output increases
- when the wind speed increases to the rated wind speed (usually around 12-13 metres per second), the generator will output its nameplate-rated capacity (i.e. a 750-kW turbine would now output 750 kW)
- as the wind speed continues to increase, the generator output will remain at the rated capacity (i.e. 750 kW) until the wind reaches the cut-out speed (usually around 25 metres per second)
- at this wind speed, the turbine will deploy its tip-brakes and then apply its disk brake, stopping the blades in a few revolutions
- it will then rotate itself 90 degrees out of the wind and park itself
- if the wind speed drops to a level below the cut-out speed for a sufficient length of time, the turbine will point itself back into the wind, release the brake, and resume power production.