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.The different parts
of a hydroelectric power plant are
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.
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.
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 transfered 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.
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