Hydro Electric Power Plant
Vijay Marcel D
M.Tech(RE) - I Year
Non Renewable Energy
Hydro electric power plant - Intro
• Hydro electric power plant harness power from
water under pressure to generate power.
• Nearly 30% of the total power generated by world
is met by hydro electric.
• In India the first major hydro electric scheme was
implemented as Sivasamudram scheme in
Mysore with 4.5MW capacity.
Selection of site
• The site for Hydraulic power plant is selected
considering the following factors
Storage of water.
Head of water.
Distance from load center.
Accessibility of the site.
The land of site should be cheap and rocky.
Power house and equipment.
• Reservoir is used to store water behind the
dam which is utilized by hydro electric plant
to produce the water.
• Reservoir may be natural or artificial.
• Water held in the upstream reservoir is called
storage and water behind the dam at the plant
is called pondage.
• A Dam is a structure of masonry built at a
suitable location across a river.
• The primary function of the dam is to provider
the head of water.
• Dams are classified based on
Dams - Classification
• Forebay acts as a regulating reservoir
• The forebay has the following parts
• It is provided for preventing the debris from
getting into the intakes from dam or from the
• Trash rack is made up of steel bars
• The spacing of bars depends upon the following
Type of turbine
Size of floating material
Velocity of flow through trash rack.
• A waterway is used to carry water from the dam to
• It includes canal, penstock and tunnel
• Tunnel is the passage by cutting mountain to
reduce the length of waterway to reservoir and the
• The tunnel is either circular or horse shoe shaped.
• A canal is an open structure constructed on earth
• The canal should be located on the economically
• Penstock is a pipe which carry the water from
reservoir to turbine house.
• Penstock is made up of steel or reinforced
concrete or wood.
• Penstock should be sloping towards the
• Sharp bends should be avoided and require
special anchorages .
• The intake of the penstock should be at a low
level to provide adequate water seal under all
• A Draft tube connects the
runner exit to tail race.
• Draft tube provides a
negative head at the
runner outlet by which it is
possible to attach a turbine
above the tail race.
• The outlet velocity of
water is reduced and a
gain in pressure head i.e.
the net working head of
turbine is increased.
• Surge tank is a storage reservoir fitted to a
• It controls the pressure variations resulting from
the rapid change in water flow from penstock and
thereby prevents water hammer effects.
• It’s function is to control water when load on
turbine decreases and supplies water when the
load on the turbine increases.
Power house and equipment
• In the powerhouse conversion of energy of water
to electrical energy takes place.
• It has the following equipments
Relief valve for penstock fittings
Switch board equipment and instruments
Low tension and high tension bus bar
Flow measurement equipments
• Hydraulic turbines are classified into two types they
• Hydraulic turbine has the following parts
• The impulse turbines are used for high head power
plants and reaction turbines are used for low and
medium head power plants.
Advantages of hydro electric power
• Water is cheapest and reliable source of generation
of electric power.
• It’s maintenance cost is low
• No fuel transportation problem
• Running cost of plant is low
• The life of plant is more and effect of age is
comparatively small on the overall efficiency of
• In addition to power generation it is used for
irrigation and flood control purposes.
Disadvantages of hydro electric power
• The power produced by the plant depends upon
quantity of water in the dam and rainfall.
• The cost of transmission is high
• Erection of the plant takes long time
• Initial cost of the plant is high.
Vijay Marcel D
M.Tech(RE) – I Year