REP Wind Power Technologies 2 — Questions and Answers
Question 1: What is the primary purpose of a wind turbine's pitch control system?
- Adjust blade angle to optimize power output and prevent overspeed (Correct answer)
- Control the yaw direction of the nacelle
- Regulate generator voltage output
- Monitor wind speed at hub height
Correct answer: Adjust blade angle to optimize power output and prevent overspeed
Pitch control adjusts the angle of attack of rotor blades to maximize energy capture at low winds and limit power at high winds to prevent mechanical damage.
Question 2: Which wind turbine configuration places the rotor downwind of the tower?
- Upwind turbine
- Downwind turbine (Correct answer)
- Horizontal axis turbine
- Darrieus turbine
Correct answer: Downwind turbine
Downwind turbines position the rotor on the lee side of the tower, allowing the rotor to self-align with the wind but experiencing tower shadow effects.
Question 3: What does the term 'wake effect' refer to in a wind farm context?
- The startup procedure after turbine shutdown
- Reduced wind speed and increased turbulence downstream of a turbine (Correct answer)
- The electrical wake-up signal sent to dormant turbines
- Morning fog that reduces turbine efficiency
Correct answer: Reduced wind speed and increased turbulence downstream of a turbine
The wake effect describes the turbulent, lower-velocity airflow that exists behind an operating turbine, which reduces energy output of downwind turbines.
Question 4: A wind turbine rated at 2 MW with a capacity factor of 35% would produce approximately how many MWh annually?
- 4,380 MWh
- 6,132 MWh (Correct answer)
- 7,000 MWh
- 8,760 MWh
Correct answer: 6,132 MWh
Annual production = 2 MW × 8,760 hours/year × 0.35 capacity factor = 6,132 MWh.
Question 5: What is the function of a nacelle in a horizontal-axis wind turbine?
- Supports the foundation and anchors the tower
- Houses the gearbox, generator, and drive train components (Correct answer)
- Stores excess electrical energy during low demand
- Provides aerodynamic fairing for the tower
Correct answer: Houses the gearbox, generator, and drive train components
The nacelle is the enclosure mounted atop the tower that contains the mechanical and electrical components including the gearbox, generator, and control systems.
Question 6: Which foundation type is most commonly used for offshore wind turbines in shallow water (up to ~30 meters)?
- Floating spar-buoy
- Tension-leg platform
- Monopile (Correct answer)
- Tripod jacket
Correct answer: Monopile
Monopile foundations—single large steel tubes driven into the seabed—are the dominant foundation choice for offshore turbines in water depths up to approximately 30 meters.
Question 7: What is 'yaw error' in wind turbine operation?
- Blade fatigue caused by uneven loading
- Misalignment between the rotor axis and wind direction (Correct answer)
- Electrical phase imbalance in the generator
- Excessive tower oscillation during high winds
Correct answer: Misalignment between the rotor axis and wind direction
Yaw error is the angular difference between the rotor's facing direction and the actual wind direction, which reduces energy capture and increases fatigue loads.
REP Wind Power Technologies 2
What is the primary purpose of a wind turbine's pitch control system?