Layout of hydeo-electric power plant

The constituents of a hydroelectric plant are,

  1. Hydraulic structure
  2. Water turbines
  3. electrical equipment

Hydraulic structure


A dam is a barrier which the river flow exceeds the head.


There are times when the river flow exceeds the storage capacity of the reservoir. Such a situation arises during heavy rainfall in the catchment area. In order to discharge the surplus water from the storage reservoir into the river on the down –steam side of the dam, spillways are used.


The headwork consists of the diversion structure at the head of the head intake the flow of water into and through head works should be as possible to avoid heat loss.

Surge tank

A surge tank is a small reservoir or tank [open at the top] in which a surge tank is located near the beginning of the conduit i.e. the quantity of water flowing in the conduit is just sufficient to meet the turbine requirements.


Penstocks are open or closed conduits which carry water to the turbines. concrete penstocks are suitable for low head [<30m]as greater pressure penstocks increase with the head the OR working pressure.


  • Once a dam is constructed, electricity can be produced at a constant rate.
  • If electricity is not needed, the sluice gats can be shunt stopping electricity generation.
  • It is quite neat and clean as no n smoke or ash is produced.
  • It is comparatively simple in construction and requires less maintainer.
  • Robust and has a longer life.


  • It involves high capital cost due to the construction of the dam.
  • It requires a high cost of   transmission lines as the plant is located in hilly areas which area which is quite away from the consumers.

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