Electrical energy is a very convenient form of energy and it can be easily Converted into other forms. To meet the ever increasing use of electric power we have to generate more electricity, here comes the necessity of generating station. Electrical energy can be generated, transmitted and distributed. There are 4 types.hydro electric, thermal, nuclear and diesel power station

Hydro electric power station It utilizes the potential energy of water at a high level. Location: there must be ample quantity of water at sufficient head. Suitable site must be available. Water head is created by constructing a dam across a river or lake. Conversion: P.E- K.E- M.E- E.E

IDUKKI DAM

Elements of a Hydraulic plant Storage reservoir:They store water It can be natural or artificial They are lakes found in high mountains Dam: It’s a solid curve structure which resist water pressure by its weight Pressure tunnel: connect water to valve house Surge tank: regulate water pressure Penstock: A large pipe made of steel or reinforced concrete which carry water to power house. Power house: It contain hydraulic turbines and ac generator. Valve house contain 2 valves. main sluice valve for cutting of water flow to the power station. automation isolating valve for cutting of water supply in case the penstock bursts.

Schematic Arrangement of a hydro – electric plant A dam is constructed across a river. Reservoir is connected to the valve house through a pressure tunnel. A surge tank is provided at P.T, for better regulation of water pressure. A large pipe made of steel or reinforced concrete called penstock, carry water from valve house to power station.

Water turbine in P.S converts hydraulic energy into M.E. when water strikes on turbine. The alternator coupled to the water turbine converts M.E into E.E. When turbine rotates, the shaft connected to the magnet {rotator} also rotates inside a copper coil {stator}, thus there is a change in magnetic flux linked with it hence an induced e.m.f is produced this is how M.E converts to E.E The water remaining is discharged to the tailrace and the water flows to the main stream and the cycle continues.

ReservoirPressure tunnel Surge tank Valve house Penstock Power station Flow chart dam

Advantages No fuel is required. Reliable and cheapest in operation and maintenance Neat and clean. Longer life Irrigation and flood control is possible.

Disadvantages Require large area. Construction cost and time is high. Long transmission lines are required. Uncertainty about availability of huge amount of water.

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