RES MCQ Unit 2

At optimum tip speed ratio, torque of wind turbine is

• Directly proportional to its angular velocity

• Directly proportional to the square of its angular velocity

• Inversely proportional to its angular velocity

• None of the above

At optimum tip speed ratio, the mechanical power developed by the wind turbine is

• Directly proportional to its angular velocity

• Directly proportional to the square of its angular velocity

• Directly proportional to the cube of its angular velocity

• Inversely proportional to its angular velocity

The power contained in the wind is say 1MW. At a pitch angle of 15 degrees, the mechanical power developed is 800KW.

The above statement is

• Can be true

• Cannot be true

• Can be true depending on the pitching of the blade

• Can be true depending on the wind velocity

Angle of attack is

• The angle between the chord and the direction of wind

• The angle between the chord and the direction of relative wind

• The angle between the vertical and the direction of relative wind

• None of the above

Consider the following statements:

1) The turbine starts generating power beyond the cut in velocity.

2) The turbine operates in constant power mode between the cut-in speed and rated speed.

• Both statements are true

• Both statements are false

• First statement is true, second statement is false

• First statement is false, second statement is true

Consider the following statements:

1) At furling speed, turbine is stopped and brakes are applied.

2) Between cut in speed and rated speed, the turbine tracks and operates at maximum power.

• Both statements are true

• Both statements are false

• First statement is true, second statement is false

• First statement is false, second statement is true

Which type of wind turbines are preferred?

• Turbines running at fixed speed

• Turbines running at a variable speed depending on the wind velocity

• Turbines running at a variable speed to keep tip speed ratio constant

• None of the above

Which type of wind turbine is essentially a constant speed turbine?

• Synchronous generator with converter

• Doubly fed induction generator

• Squirrel cage induction generator connected to grid

• Wound rotor induction generator with rotor resistance control

Consider the following statements:

PMSG can operate without a gearbox.

PMSG can control reactive power.

• Both statements are true

• Both statements are false

• First statement is true, second statement is false.

• First statement is false, second statement is true

Consider the following statements:

1)Converters used with PMSG need to handle < 30% power.

2)PMSG based wind turbine has to run at constant speeds.

• Both statements are true.

• Both statements are false.

• First statement is true, second statement is false

• First statement is false, second statement is true.