Hydroelectric Power Plant Interview Questions & Answers

  1. Question 1. What Are The Essential Elements Of The Hydroelectric Power Plant?

    Answer :

    Some of the essential elements of hydroelectric power plant are:

    1. Catchment area 
    2. Reservoir 
    3. Dam 
    4. Spillways 
    5. Conducts 
    6. Surge tanks 
    7. Draft Tubes 
    8. Power House 
    9. Switchyard for transmission of power
  2. Question 2. What Is The Significance Of Dam?

    Answer :

    • Dam performs the following two basic functions.
    • It develops a reservoir of the desired capacity to store water.
    • It builds up the head for power generation.
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  4. Question 3. What Are Hydrograph And Its Significance?

    Answer :

    Hydrograph is a graphical representation between the discharge or flow with time. It is plotted with flow as ordinates (Y-axis) and time intervals as abscissas ( X-axis). The ordinates may be plotted in terms of the gauge height, the number of cubic meters per second per square kilometer, the power in kW that can be developed. The abscissas may be taken in terms of hours, days, weeks or months. It also indicates the power available from the stream at different times of the day or year (particular period). Hydrograph is similar to load curve and used to study the electric power.

    A Hydrograph provides the following information:

    • The discharge at any time during the period under consideration.
    • The maximum and minimum runoff during the period.
    • The average run-off during the period.
    • Total volume of the discharge up to any time, given by the area under the curve up to that time.
  5. Question 4. What Is The Use Of Spillway?

    Answer :

    When the water level in the reservoir basin rises, the stability of the dam structure is endangered. To relieve the reservoir of this excess water, a structure is provided in the body of the dam. This structure is called spillway. This is constructed to act as safety value. This provides structural stability of the dam under conditions of the floods without raising the reservoir level above High Flood Level.

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  7. Question 5. What Is Mass Curve?

    Answer :

    Mass curve indicates the total volume of run-off in m3 up to certain time. The abscissa may be day, month or year. This curve is obtained from the records of average monthly flow. The slope of curve at any point gives the rate of flow at that time. These curves are used to determine the capacity of the storage reservoirs for hydro projects.

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  9. Question 6. What Is Called Hydro Electric Power Station?

    Answer :

    The power station, in which the kinetic energy of water is converted into electrical energy, is called hydro-electric power station.

  10. Question 7. What Is The Source Of Generation In The Hydroelectric Power Station?

    Answer :


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  12. Question 8. What Are The Different Sections Of A Hydroelectric Power Station?

    Answer :

    The different sections of a hydroelectric power station are dams, spillways, gates, penstock & hydroelectric generators.

  13. Question 9. What Is The Function Of The Dam In A Hydroelectric Power Station?

    Answer :

    The function of dam is to create required water head and store water in catchment area.

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  15. Question 10. Where Is Water Stored?

    Answer :

    Water is stored in the reservoir of the catchment area.

  16. Question 11. What Are The Factors To Be Considered In Selecting The Site Of A Hydroelectric Power Plant?

    Answer :

    The following factors are to be considered for selecting the site of a hydro-electric power plant:-

    • Since potential energy of water fall or kinetic energy of flowing stream is utilized in the hydro-electric power plant, therefore water must be available in sufficient quantity at a good head or huge quantity of water is flowing across a given point.
    • The site must be convenient for the creation of the dam and must have topographical suitability for the erection of reservoir.
    • The rivers feeding the reservoir must have a large catchment area. so that water level in the reservoir may not fall below the minimum required in the dry season.
    • The land must be rocky in order to withstand the heavy weight of large building of the dam.
    • The site should be accessible and habitable.
    • There should be the possibility of stream diversion during the construction period.
    • The project should not cause the serious ecological problem.
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  18. Question 12. What Are The Merits & Demerits Of The Hydro-electric Power Station?

    Answer :


    • The layout, construction, and operation of the plant are simple.
    • Maintenance cost is low.
    • It can be started and put into service instantly.
    • It can take varying load easily.
    • It has no standby losses.
    • No fuel charges are required.
    • Less number of operational staff is required.
    • The efficiency is quite high about 75% to 85%.


    • Large area is required.
    • It takes a long time for erection.
    • The construction cost is very high.
    • Long dry season may affect the operation.
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  20. Question 13. What Is The Water Turbine?

    Answer :

    Water turbine is a prime mover used for the alternator at the hydro electric power plant which changes the direction of the flowing water and converts the same to useful mechanical energy and also gives mechanical energy to the alternator.

  21. Question 14. What Are The Types Of Water Turbines Used In A Hydroelectric Power Plant?

    Answer :

    There are two types of turbines, namely:

    1. Impulse turbine,
    2. Reaction turbine.
  22. Question 15. What Is The Method Of Selection Of Water Turbines?

    Answer :

    Impulse turbine is selected for very high heads and a small quantity of water as it utilizes the kinetic energy of water. Reaction turbine is selected for low and medium head and the large quantity of water as it utilizes the pressure of the water.

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  24. Question 16. What Are The Classifications Of The Hydro-electric Power Station According To Its Heads?

    Answer :

    1. Low head up to 60 meters.
    2. Medium head from 60 meters to 300 meters. 
    3. High head above 300 meters.
  25. Question 17. What Is The Utility Of Multipurpose Hydroelectric Project?

    Answer :

    It provides power generation, irrigation, fishery and flood control at the same time.

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  27. Question 18. What Are The Names Of Leading Hydro-electric Power Station Installed In India?

    Answer :

    Bhakra Nangal, Chambal project, Kayla etc.

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  29. Question 19. How Is Water Turbines Mounted?

    Answer :

    The impulse turbine is mounted horizontally whereas the reaction turbine is mounted vertically.