HYDRO POWER PLANT

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.

Depending upon the load on the turbine, the amount of water needed is controlled automatically by a valve operated by a centrifugal governor.

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.