Turbines and Generators in Hydropower: A Comprehensive Guide for University Students

Question 1

Which type of turbine is commonly employed in large-scale hydropower facilities?

Accepted Answer

Francis turbine

Answer

Pelton turbine

Answer

Kaplan turbine

Question 2

In a hydropower system, what is the governor's primary function?

Accepted Answer

Controlling turbine speed

Answer

Regulating water flow through the turbine

Answer

Generating electricity

Question 3

How is the output voltage of a generator in a hydropower plant typically regulated?

Accepted Answer

By adjusting the field excitation

Answer

By controlling the rotor speed

Answer

By utilizing an external voltage regulator

Question 4

What is the purpose of a tailrace in a hydropower plant?

Accepted Answer

To discharge water downstream after passing through the turbine

Answer

To regulate the flow of water

Answer

To enhance water pressure

Question 5

For a hydropower site with a high water head and low water flow rate, which turbine type is most appropriate for electricity generation?

Accepted Answer

Pelton turbine

Answer

Francis turbine

Answer

Kaplan turbine

Answer

Turgo turbine

Question 6

Which type of turbine is commonly utilized in high-head hydropower plants with constricted water passages?

Accepted Answer

Pelton turbine

Answer

Francis turbine

Answer

Kaplan turbine

Answer

Cross-flow turbine

Question 7

What is the primary function of a draft tube in a hydropower plant?

Accepted Answer

To reduce cavitation by lowering the pressure at the turbine outlet

Answer

To convert the kinetic energy of water into rotational energy

Answer

To increase the pressure of water entering the turbine

Answer

To control the flow rate of water through the turbine

Question 8

Which type of generator is typically employed in large-scale hydropower plants?

Accepted Answer

Synchronous generator

Answer

Induction generator

Answer

Permanent magnet generator

Answer

DC generator

Question 9

What is the purpose of the wicket gates in a Francis turbine?

Accepted Answer

To control the flow rate of water entering the turbine

Answer

To adjust the speed of the turbine

Answer

To prevent cavitation

Answer

To regulate the voltage output of the generator

Question 10

Which type of hydropower plant is most suited for low-head applications?

Accepted Answer

Run-of-the-river

Answer

Dam-based

Answer

Pumped-storage

Answer

Tidal

Question 11

In high-head hydropower plants, which turbine type is primarily employed?

Accepted Answer

Pelton turbine

Answer

Francis turbine

Answer

Kaplan turbine

Answer

Cross-flow turbine

Question 12

In a hydropower plant, the function of a draft tube is to:

Accepted Answer

Recover kinetic energy from water exiting the turbine

Answer

Elevate the pressure of water entering the turbine

Answer

Control the water flow rate through the turbine

Answer

Prevent cavitation within the turbine

Question 13

Which factor does NOT influence generator efficiency?

Accepted Answer

Temperature

Answer

Strength of the magnetic field

Answer

Friction-related losses

Answer

Quantity of poles

Question 14

In small-scale hydropower facilities, which generator type is typically utilized?

Accepted Answer

Permanent magnet generator

Answer

Synchronous generator

Answer

Asynchronous generator

Answer

Induction generator

Question 15

What is the primary purpose of a governor in a hydropower plant?

Accepted Answer

Regulate water flow through the turbine

Answer

Maintain consistent voltage output

Answer

Protect the generator from overloads

Answer

Synchronize the generator with the grid

Question 16

Which technology is considered a renewable energy source?

Accepted Answer

Hydropower

Answer

Coal

Answer

Nuclear

Answer

Natural gas

Question 17

For a hydropower site with a high head and low flow rate, which turbine type is most suitable?

Accepted Answer

Pelton

Answer

Francis

Answer

Kaplan

Answer

Turgo

Question 18

What is the primary function of a draft tube in a hydropower system?

Accepted Answer

Increase turbine efficiency by reducing pressure

Answer

Store excess water for later use

Answer

Regulate water flow into the turbine

Answer

Convert kinetic energy into electrical energy

Question 19

Which factor does NOT affect the efficiency of a hydroelectric generator?

Accepted Answer

Water temperature

Answer

Number of poles

Answer

Rotational speed

Answer

Magnetic field strength

Question 20

Which method is primarily used to control the output voltage of a hydroelectric generator?

Accepted Answer

Field excitation

Answer

Load control

Answer

Governor control

Answer

Speed regulation

Question 21

What is the relationship between the number of poles in a generator and the frequency of the generated electricity?

Accepted Answer

Directly proportional

Answer

Inversely proportional

Answer

Square root relationship

Answer

No relationship

Question 22

Which type of generator is typically preferred for large-scale hydropower plants?

Accepted Answer

Synchronous generator

Answer

Asynchronous generator

Answer

DC generator

Answer

Permanent magnet generator

Question 23

Which type of turbine is commonly employed in high-head applications, featuring a vertical shaft orientation?

Accepted Answer

Pelton turbine

Answer

Kaplan turbine

Answer

Francis turbine

Answer

Deriaz turbine

Question 24

In a hydropower system, what is the primary function of a governor?

Accepted Answer

Controlling the speed of the generator

Answer

Regulating water flow to the turbine

Answer

Converting mechanical energy into electrical energy

Answer

Storing energy for peak demand periods

Question 25

Which factor significantly influences the efficiency of a Kaplan turbine?

Accepted Answer

Blade angle

Answer

Runner diameter

Answer

Water head

Answer

Speed of rotation

Question 26

In a hydropower plant, what is the purpose of a draft tube?

Accepted Answer

Reducing water pressure after exiting the turbine

Answer

Increasing water pressure before entering the turbine

Answer

Guiding water flow smoothly into the turbine

Answer

Generating additional power from discharged water

Question 27

Which type of generator is specifically designed for variable-speed applications in hydropower plants?

Accepted Answer

Doubly-fed induction generator

Answer

Synchronous generator

Answer

Asynchronous generator

Answer

Permanent magnet generator

Question 28

Which performance characteristic is used to evaluate the efficiency of a hydropower plant?

Accepted Answer

Overall efficiency

Answer

Specific speed

Answer

Hydraulic efficiency

Answer

Mechanical efficiency

Question 29

Which type of turbine blade is designed to handle high water velocities?

Accepted Answer

Pelton bucket

Answer

Kaplan blade

Answer

Francis blade

Answer

Propeller blade

Question 30

In a hydropower plant, how does the power factor of the load affect the efficiency of the generator? Suggest practical steps to improve the generator's efficiency.

Accepted Answer

Adding capacitors to the load circuit can improve power factor and generator efficiency.

Answer

The power factor has no impact on generator efficiency.

Answer

A lower power factor increases generator efficiency.

Answer

Generator efficiency is solely determined by its design and cannot be influenced by external factors.

Question 31

Which of the following accurately describes a key difference between Kaplan and Pelton turbines?

Accepted Answer

Kaplan turbines are designed for low water heads, whereas Pelton turbines are suitable for high water heads.

Answer

Kaplan turbines have superior efficiency compared to Pelton turbines.

Answer

Pelton turbines operate at faster speeds than Kaplan turbines.

Question 32

In a hydropower plant, what is the primary function of a generator?

Accepted Answer

Converting mechanical energy from the turbine into electrical energy.

Answer

Regulating the voltage of the electrical output.

Answer

Controlling the flow of water passing through the turbine.

Question 33

Which of the following factors influence the efficiency of a turbine?

Accepted Answer

Head, flow rate, and blade design

Answer

Blade design alone

Answer

Head alone

Answer

Flow rate alone

Question 34

What is the purpose of a draft tube in a turbine system?

Accepted Answer

Recovering kinetic energy from the water exiting the turbine.

Answer

Enhancing the efficiency of the generator.

Answer

Regulating the flow of water through the turbine.

Question 35

For small-scale hydropower plants, which type of generator is commonly employed?

Accepted Answer

Permanent magnet generator

Answer

Synchronous generator

Answer

Induction generator

Question 36

What is a primary advantage of using a synchronous generator in a hydropower plant?

Accepted Answer

It allows for precise control of voltage and frequency in the electrical output.

Answer

It is less expensive than other generator types.

Answer

It has higher efficiency compared to other generator types.

Question 37

What is the primary role of a governor in a hydropower plant?

Accepted Answer

To regulate the turbine's speed and maintain a stable power output.

Answer

To measure the flow rate of water.

Answer

To initiate and halt the turbine's operation.

Question 38

When selecting a turbine for a specific hydropower site, which factor is crucial to consider?

Accepted Answer

Water head and flow rate

Answer

Environmental impact

Answer

Installation costs

Answer

Generator size

Question 39

What are the primary environmental benefits associated with using hydropower as a renewable energy source?

Accepted Answer

Reduced emissions of greenhouse gases and minimized water pollution.

Answer

High energy density

Answer

Low operating expenses

Question 40

Which turbine type is most appropriate for high-head, low-flow applications?

Accepted Answer

Pelton

Answer

Kaplan

Answer

Francis

Question 41

Which factor exerts the greatest influence on turbine efficiency?

Accepted Answer

Blade design

Answer

Turbine speed

Answer

Water temperature

Answer

Generator size

Question 42

What is the function of a draft tube in a turbine system?

Accepted Answer

Recover pressure energy from the discharged water.

Answer

Cool the turbine shaft.

Answer

Increase the water flow rate to the turbine.

Answer

Mitigate cavitation on turbine blades.

Question 43

In large-scale hydropower plants, which generator type is typically employed?

Accepted Answer

Synchronous

Answer

DC

Answer

Induction

Answer

Permanent magnet

Question 44

What is the key distinction between Kaplan and Francis turbines?

Accepted Answer

Kaplan turbines have adjustable blades, while Francis turbines have fixed blades.

Answer

Francis turbines surpass Kaplan turbines in efficiency at low flow rates.

Answer

Kaplan turbines operate at higher head ranges than Francis turbines.

Question 45

What is the purpose of reactive power compensation in a hydropower system?

Accepted Answer

To maintain voltage stability and minimize power losses.

Answer

To reduce turbine wear.

Answer

To enhance generator efficiency.

Question 46

What is the primary function of the penstock in a hydropower plant?

Accepted Answer

Convey water from the reservoir to the turbine.

Answer

Regulate the water flow to the turbine.

Answer

Store water for peak power generation.

Question 47

What is the main benefit of employing a synchronous condenser in a hydropower system?

Accepted Answer

Provide reactive power compensation and voltage regulation.

Answer

Reduce turbine maintenance costs.

Answer

Increase generator output.