REP Wind Power Technologies 3

Question 1

What is the Weibull distribution used for in wind energy analysis?

Accepted Answer

Statistically describing the frequency distribution of wind speeds at a site

Answer

The Weibull distribution is the standard statistical model used to characterize the probability distribution of wind speeds at a given location for energy yield assessments.

Question 2

Direct-drive wind turbines eliminate which major component compared to conventional turbines?

Accepted Answer

The gearbox

Answer

Direct-drive turbines connect the rotor shaft directly to a low-speed generator, eliminating the gearbox and its associated maintenance requirements and failure modes.

Question 3

Which IEC wind turbine class designation indicates the highest wind speed design environment?

Accepted Answer

IEC Class I

Answer

IEC Class I turbines are designed for high-wind sites with average wind speeds up to 10 m/s, while Class III covers lower-wind sites up to 7.5 m/s average.

Question 4

What phenomenon causes the 'three-per-revolution' (3P) excitation in a three-bladed wind turbine?

Accepted Answer

Each blade passing the tower once per revolution, creating periodic loading

Answer

Each of the three blades passes the tower once per revolution, creating three structural load pulses per revolution known as 3P excitation.

Question 5

What is the primary advantage of variable-speed wind turbines over fixed-speed designs?

Accepted Answer

Ability to operate at optimal tip-speed ratio across a wider wind range

Answer

Variable-speed turbines adjust rotor speed to maintain optimal tip-speed ratio as wind speed changes, capturing more energy across a broader range of wind conditions.

(REP) Certified Renewable Energy Professional Practice Test

(REP) Certified Renewable Energy Professional Practice Test

REP Wind Power Technologies 3