Powerhouse Planning

1.1 Classification, general arrangement and layout plan of powerhouse

Power house:

  • Structural complex where all the equipment for producing and providing electricity are suitably arranged.

Classification of powerhouse:

a. Surface powerhouse:

  • Located on the surface of the land so that it has less space restriction.
  • Foundation analysis of such structure should be examined carefully.
  • If solid bed is not available in surface powerhouse special treatment should be done.

b. Underground powerhouse:

  • If there is restriction or not enough space then this powerhouse is constructed.
  • Economical.

General arrangement of powerhouse:

1.Superstructure:

  • The structure from generator floor to roof of power house.
  • Consist of generator, control room, auxiliary equipment needed for ventilation and cooling.

2.Intermediate structure:

  • The structure from turbine axis to top of generator.
  • Consist of casing, generator and its appurtenances.
  • Access to turbine runner.

3.Sub structure:

  • Structure that is situated below the axis of turbine.
  • Consist of draft tube, tail water channel and galleries.

1.2 General dimension calculation of powerhouse

1.Machine hall (Unit bay)

a. Length:

  • The length of machine hall depends upon the number of units, the distance between the units, size of machine and the clearance.
  • The standard distance of scroll casing is about 4.5D to 5D.

Where, D= Diameter of turbine

  • Minimum clearance is about 2 to 3m.

b. Width:

  • Width of machine hall is also determined by the size and clearance space from the walls.
  • Width of machine hall can be (5D+2.5)m.
  • Width is kept as less as possible.

c. Height:

  • Height of machine hall is fixed up by head room requirement of crane operation.
  • Generally, 2 to 2.5 m head requirement is for crane operation.

2. Loading Bay:

  • It is a space where the heavy vehicle can be loaded and unloaded.
  • Dismantled parts of machine can be placed and assembling of equipment is done.
  • Load bay floor will have width at least equal to the center distance of machine.

3. Control Bay:

  • Main room where equipment like runner, gate valve, generator etc are controlled.
  • It may be adjacent to the machine hall as it sends instruction to operation bay.

References:

  • Dandekar, M. M., & Sharma, K. N. (2010). Water Power Engineering. Vikas Publishing House.
  • Punmia, B. C., Pande, B. B. L., Jain, A. K., & Jain, A. K. (2016). Irrigation and Water Power Engineering. Laxmi Publications.
  • Singh, Bharat (2018). Fundamentals of Hydrology and Hydropower Engineering. Nem Chand & Bros.
  • Central Water Commission, Government of India (2019). Handbook on Hydroelectric Engineering.
  • International Energy Agency (IEA) (2021). Hydropower Status Report. Retrieved from www.iea.org
  • Nepal Electricity Authority (NEA) (2022). Annual Report on Hydropower Projects in Nepal. Retrieved from www.nea.org.np
  • United States Bureau of Reclamation (2020). Design of Small Dams. U.S. Government Printing Office.

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