REP Wind Power Technologies 4

Question 1

What is the 'cut-in wind speed' of a wind turbine?

Accepted Answer

The minimum wind speed at which the turbine begins generating electricity

Answer

Cut-in wind speed (typically 3–4 m/s) is the minimum wind speed at which a turbine's rotor produces enough torque to generate net positive electrical output.

Question 2

Which atmospheric layer is most relevant to wind turbine operation and resource assessment?

Accepted Answer

Atmospheric boundary layer

Answer

The atmospheric boundary layer (lowest ~1–2 km of the atmosphere) is where wind turbines operate and where surface friction, thermal gradients, and turbulence most affect wind resources.

Question 3

What does a turbine's 'power curve' depict?

Accepted Answer

Power output as a function of wind speed

Answer

A turbine's power curve is a graph showing electrical power output (kW or MW) at each wind speed from cut-in through rated to cut-out conditions.

Question 4

Why are wind turbine blades twisted along their length?

Accepted Answer

To account for varying relative wind angles from root to tip due to rotational speed

Answer

Blade twist compensates for the fact that tip sections move much faster than root sections, ensuring each blade section encounters wind at an optimal angle of attack.

Question 5

What is 'curtailment' in the context of wind power generation?

Accepted Answer

Deliberate reduction of turbine output below available capacity

Answer

Curtailment is the intentional reduction of a wind farm's output, typically ordered by grid operators when generation exceeds transmission capacity or grid demand.

(REP) Certified Renewable Energy Professional Practice Test

(REP) Certified Renewable Energy Professional Practice Test

REP Wind Power Technologies 4