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Energy Engineering Multiple Choice Questions on “Classification of Hydro-Plant”.
1. What type of Hydro plant is it if the Plant head is above 100m?
A. High head hydro-plant
B. Medium head hydro-plant
C. Low head hydro-plant
D. Base load hydro-plant
View Answer
Answer: A
clarification: If the head of water available is above 100m, the plant is known as a high head plant. IN this head, water available for producing electricity is very high and it can extend to 1000 meters. These are most commonly constructed hydro plants.
2. Which type of hydro plant is it if the head of a hydro plant is 30 – 100m?
A. High head hydro-plant
B. Medium head hydro-plant
C. Low head hydro-plant
D. Base load hydro-plant
Answer: B
clarification: If the water available is more than 30m but less than 100m, than this type of plant is known as medium head plant. Water stored in fore bay is conveyed to the turbine through penstocks. In these plants the river water is tapped off to a fore bay on one bank of rive.
3. Low head hydro plant is also known as ____________
A. Canal power plant
B. Medium head hydro-plant
C. Run-off river hydro-plant
D. Base load hydro plant
Answer: A
clarification: Low head hydro electric power plant is also known as canal power plant. The dam in this type of power plant is of very small head may be even few meters only. The low head type of power plants cannot store water.
4. Which plants supply the peak load for the base power plants?
A. Mini hydel plants
B. Pump storage power plants
C. Low head plants
D. Run-off river power plants
Answer: B
clarification: Pumped storage plants supply the peak load for the base power plants and pump all or a portion of their own water supply. The plant contains a tail water pond and a head water pond connected by a penstock.
5. Which plants are used with steam and IC engines?
A. Pumped storage plants
B. Mini hydel plants
C. Low head Hydel plant
D. Run-off river plants
Answer: A
clarification: Pumped storage plants can be used with hydro, steam and IC engines. The generating pumping unit is at the lower end. During off peak hours some of the surplus electric energy generated by the base plant is utilized to pump water from tail water pond into the head water pond.
6. Which type of turbines does modern hydro power plant use?
A. Kaplan turbine
B. Francis turbine
C. Pelton wheel
D. Cross flow turbine
Answer: B
clarification: Modern power plants use Francis turbine. Francis turbine is a water turbine developed by James Francis. It is an inward flow reaction turbine that combines radial and axial flow concepts. These are primarily used for electric production.
7. Which type of hydro power plant can be with or without pondage?
A. Mini hydel plants
B. Pump storage power plants
C. Low head plants
D. Run-off river power plants
Answer: D
clarification: Run-off river power plants can be with or without pondage. A runoff river plant without pondage has no control over river flow and uses water as it comes. The runoff river plant with pondage may supply base load power.
8. The surge tank controls the water when the load on the turbine is ________
A. Equal
B. Decreased
C. Increased
D. Not present
View Answer
Answer: B
clarification: The surge tank controls the water when the load on the turbine decreases. The excess water is stored in the surge tank and hence the pressure variations in the penstock are taken care of preventing water hammer.
9. Which type of valves is preferred for moderate heads?
A. Butterfly valve
B. Tube valve
C. Needle vale
D. Globe valve
View Answer
Answer: A
clarification: For moderate heads butterfly valves are preferred. Gate valves are used to regulate the flow. This valve is used both as intake gate and as turbine valve. It helps inspection without dewatering the penstock line.
10. Which type of gate valves are used in high head installations?
A. Needle valves
B. Butterfly valves
C. Globe valve
D. Pinch valve
Answer: A
clarification: Needle valves are used in high head installations. The needle valve consists of three water filled chambers A, B and C in which hydraulic pressures can be varied. The valves are opened and closed by varying the pressures in these chambers.