WTT Wind Turbine Components & Design 3

Question 1

What is the primary role of the yaw system in a horizontal-axis wind turbine?

Accepted Answer

To rotate the nacelle so the rotor faces into the wind

Answer

The yaw system continuously rotates the nacelle about the vertical tower axis to keep the rotor aligned with the wind direction for maximum energy capture.

Question 2

In a doubly fed induction generator (DFIG) wind turbine, power is fed to the grid from:

Accepted Answer

Both the stator and rotor windings simultaneously

Answer

DFIG turbines inject power into the grid from both the stator directly and the rotor through back-to-back power converters, enabling variable-speed operation.

Question 3

Which bearing type is commonly used at the main shaft of a wind turbine to handle combined radial and axial (thrust) loads?

Accepted Answer

Spherical roller bearing or tapered roller bearing

Answer

Spherical or tapered roller bearings are used at the main shaft because they can carry the large combined radial loads from rotor weight and axial thrust from wind pressure.

Question 4

What is the purpose of a wind turbine's transformer located at the base of the tower?

Accepted Answer

To step up generator voltage to grid transmission voltage

Answer

The pad-mount or tower-base transformer steps up the low generator voltage (typically 690 V) to medium-voltage grid level (e.g., 34.5 kV) for efficient transmission.

Question 5

What distinguishes an upwind turbine design from a downwind design?

Accepted Answer

The rotor faces into the wind on an upwind turbine, while the rotor is on the lee side on a downwind turbine

Answer

Upwind turbines position the rotor facing the oncoming wind, preventing tower shadow effects, while downwind turbines place the rotor behind the tower, which can cause blade fatigue from tower wake.

(WTT) Wind Turbine Technician Certification Practice Test

(WTT) Wind Turbine Technician Certification Practice Test

WTT Wind Turbine Components & Design 3