In a hydro power plant, the potential energy of water stored in a dam is made use
of in running a water turbine coupled to an electrical generator.
It is esti mated that bout 23 per cent of the total electric power in the world comes from hydro power.
In Tamil Nadu. the total generation of power from hydroelectric plants amounts to
1950 MW and in all India level, it amounts to about 18000 MW.
Layout of a Hydro Power Plant
The layout of a hydro power plant is given in Fig. 17.7.
The water from the dam is brought to the water turbine by a large diameter penstock pipe. The penstock pipe is made of steel or reinforced concrete.
It is desirable to eliminate sharp bends in the penstock pipe to avoid the loss of head and special anchoring.
In case the amount of water is suddenly reduced or stopped by the governor mechanism. water coming down with a high velocity will produce turbulence
resulting in a water hammer in the pipe.
The penstock pipe may be damaged due to the water hammer. To prevent this, a surge tank is provided. From the turbine, water is allowed to pass through a draft tube to the tail race.
The tail race is the water path leading the discharge water from the turbine to the river or canal.