Topic 2-Intro to WT systems

Question 1

Use the image of wind turbine, Anatomy of a Wind Turbine (EWEA), name the components
labelled as 1‐8 and 13‐14

Answer 1

Blades or rotor; 2 – Pitch drive; 3 – Nacelle; 4 – Mechanical break; 5 – Main Shaft; 6 –
Gearbox; 7 – High‐speed shaft; 8 – Generator; 13 – Yaw drive; 14 – Tower and foundation.

Question 2

What are the two most used substructure types for current offshore wind turbines?

Answer 2

Monopile and Four‐legged jacket are most used substructure types for current offshore wind
turbines.

Question 3

What are the key considerations in designing a commercial WT?

Answer 3

Power rating; rotor blade control, rotor speed (fixed or variable); design tip speed ratio, and
generator type and speed.

Question 4

What are the key advantages of designing variable‐speed WTs?

Answer 4

Variable‐speed rotors can be operated at the optimum tip speed ratio to maximize power
conversion in low wind and at lower tip speed ratios in high winds to reduce loads on the
drivetrain.

Question 5

For a variable‐speed wind turbine, when operating below the rated rotor speed, what is the
control strategy? After the wind speed reaches the rated level, how the turbine is controlled to
maintain turbine power at the rated level?

Answer 5

At low winds, the generator control is designed to extract power by automatically operating
on maximum power tracking. Above the rated wind speed, the blades pitch to maintain turbine
power at the rated value.

Question 6

What are the reference wind speeds for wind turbine classes I, II, III defined in the IEC61400‐1
international standard?

Answer 6

For wind turbine class I, II, and III, the reference wind speed is 50, 42.5 and 37.5 m/s
respectively.