HYDEL POWER PLANTS
Hydroelectric power plants
convert the hydraulic potential energy from water into electrical energy. Such
plants are suitable were water with suitable head are available.
The layout covered in this article is just a simple one and only cover the
important parts of hydroelectric plant.
HYDEL POWER PLANT:
Dams are structures built over
rivers to stop the water flow and form a reservoir. The reservoir stores the
water flowing down the river. This water is diverted to turbines in power
stations. The dams collect water during the rainy season and stores it, thus
allowing for a steady flow through the turbines throughout the year. Dams are
also used for controlling floods and irrigation. The dams should be water-tight
and should be able to withstand the pressure exerted by the water on it. There
are different types of dams such as arch dams, gravity dams and buttress dams.
The height of water in the dam is called head race.
A spillway as the name suggests
could be called as a way for spilling of water from dams. It is used to provide
for the release of flood water from a dam. It is used to prevent over toping of
the dams which could result in damage or failure of dams. Spillways could be
controlled type or uncontrolled type. The uncontrolled types start releasing
water upon water rising above a particular level. But in case of the controlled
type, regulation of flow is possible.
(3) Penstock and Tunnels
Penstocks are pipes which carry
water from the reservoir to the turbines inside power station. They are usually
made of steel and are equipped with gate systems. Water under high pressure
flows through the penstock. A tunnel serves the same purpose as a penstock. It
is used when an obstruction is present between the dam and power station such
as a mountain.
Surge tanks are tanks connected
to the water conductor system. It serves the purpose of reducing water
hammering in pipes which can cause damage to pipes. The sudden surges of water
in penstock is taken by the surge tank, and when the water requirements
increase, it supplies the collected water thereby regulating water flow and
pressure inside the penstock.
(5) Power Station
contains a turbine coupled to a generator. The water brought to the power
station rotates the vanes of the turbine producing torque and rotation of
turbine shaft. This rotational torque is transferred to the generator and is
converted into electricity.
The used water is released
through the tail race. The difference between head race and tail race is
called gross head and by subtracting the frictional losses we get the net head
available to the turbine for generation of electricity.
Ø Water the
working fluid is natural and available plenty.
Ø Life of
the plant is very long.
cost and maintenance are very low.
cost is low.
and operation costs are very less.
Ø No fuel
Ø No ash
cost of plant is very high.
generation depends on quantity of water available which depends on rainfall.
losses are very high.
Ø More time
is required for erection.