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Energy Engineering Questions and Answers for Campus interviews focuses on “Site Selection for Hydro Electric Power Plants”.
1. Water gets polluted by submerged vegetation mineral.
A. True
B. False
Answer: A
clarification: Water gets polluted by submerged vegetation mineral deposits, presence of algae, Leaves, twigs, logs under water decay and generates bad smelling gases. Thermal stratification and depletion of oxygen in lower strata generate harmful gases such CO2 which pollute the water.
2. Water containing H2S, CO2 and CH2 are less corrosive to dam structure.
A. True
B. False
Answer: B
clarification: Water containing H2S, CO2 and CH2 are highly corrosive to dam structure. H2SO4 formed by oxidation of H2S attack the cement and disintegrate the concrete. These gases increase the solubility of soil and rocks. Structures, metallic piping and penstock are also affected.
3. Presence of Corrosive gases like H2S and SO2 affect the voltage drop.
A. True
B. False
View Answer
Answer: A
clarification: Presence of Corrosive gases like H2S and SO2 does affect the voltage drop at brush contacts in generator leading to poor commutation. Silver contacts of relays get blackened and lead to high contact resistance and failure of relay occurs.
4. Which among the following reduces the capacity of reservoir and causes rapid erosion of turbine blades?
A. Contamination of highly corrosive material
B. Sedimentation effect
C. Submerged vegetation
D. Solid contamination
View Answer
Answer: B
clarification: Sediments in the aquatic ecosystem are analogous to soil in the terrestrial ecosystem as they are the source of substrate nutrients, and micro- and macro flora and -fauna that are the basis of support to living aquatic resources.
5. What is the basic requirement of hydroelectric power station?
A. Reservoir
B. Turbine
C. Power house
D. Penstock
View Answer
Answer: A
clarification: The basic requirement of a hydroelectric power station is a reservoir where large quantity of water is stored during flood season and used during dry season. The reservoir is generally built of constructing dam across river.
6. The water from is drawn by the __________
A. Canal
B. Hose
C. Stream
D. Penstock
View Answer
Answer: A
clarification: The water from reservoir is drawn by the fore bay through an open canal or tunnel. The water from fore bay is supplied to water turbine through penstock which is located at much lower level than the height of water in reservoir.
7. What is used to prevent the entry of debris into turbine?
A. Wiper
B. Fore bay
C. Trash rack
D. Filter
Answer: C
clarification: Trash rack is used to prevent the entry of debris which might damage the Wicket gate and turbine. It is a wooden or metal structure and is supported by masonry, that prevents waterborne debris from entering into penstock which than connects to turbine.
8. A pipe between surge tank and prime mover is known as?
A. Canal
B. Draft tube
C. Penstock
D. Hose
Answer: C
clarification: A pipe between the surge tank and prime mover is known as penstock. It is made of steel through reinforced concrete. Cast iron is used for small plants. The intake of penstock at the dam or fore bay of canal should be positioned such that it always provides adequate water even at low level.
9. Which type of penstock is used in cold climates?
A. Buried penstock
B. Covered penstock
C. Open penstock
D. Exposed penstock
View Answer
Answer: A
clarification: Buried penstocks are used in cold climates where freezing is expected. types of penstocks have shorter life period. A buried penstock will not be subjected to the problem of harmonic vibrations sometimes associated with the traditional penstock.
10. Which type of penstocks is less expensive?
A. Buried penstock
B. Covered penstock
C. Open penstock
D. Exposed penstock
Answer: D
clarification: Exposed penstocks are less expensive and have a longer life. Their inspection and maintenance is easier. Penstocks are not covered because exposed pipes are easily accessible. The water flow rate is 2, 4, and 7 m/s in low, medium and high head power plants respectively.
11. A safety valve for a dam to discharge major floods is called?
A. Spillway
B. Penstock
C. Fore bay
D. Canal
Answer: A
clarification: Spillway is a safety valve for a dam to discharge major floods without damage to dam. It keeps the reservoir level below some predetermined maximum level. Spillway ensures that water does not overflow and damage or destroy the dam.
12. What is introduced between the dam and power house?
A. Penstock
B. Draft tube
C. Prime mover
D. Surge tank
View Answer
Answer: D
clarification: Surge tank is introduced between the dam and power house nearest to the power house and preferably on the high ground to reduce the height of tower to provide better regulation of water pressure in the system during variable load condition.