Hydro electric power plant
An artificial storage reservoir is formed by constructing a dam across a river or lake and a pressure tunnel is taken off from the reservoir to the valve house at the start of the penstocks. The value house contains main sluice valves for controlling water flow to the power station and automatic isolation valves for cutting off water supply in case the penstocks bursts. A source tank is also provided just before the valve house for better regulation of water pressure in the system.
The water from the reservoir is carried to valve house
through pressure tunnel and from valve house to the water turbine through pipes
of largest diameter made of steel or reinforced concrete called penstock. The water turbine converts hydraulic energy into
mechanical energy and the alternator which is coupled on the same shaft of the
water turbine will converts mechanical energy into electrical energy. Water
after doing useful work is discharged to the tail race.
Advantage of
hydro-electric power plant
The following are the major advantages of hydro-electric power station, namely.
1. Water is the cheapest and reliable source of generation of electric power because it exists as a free gift from nature.
2. It is free from pollution because no smoke and ash are produced in this plant.
3. No fuel transportation problems.
4. Its maintenance cost is low.
5. These plants can be started quickly and can be brought up into function within few minutes
6. These plants has no stand by losses.
7. It requires less supervising staff.
8. Running cost of the plant is low
9. The stored water not only used power generation but also used for irrigation and flood control.
10. Hydro station are able to respond to rapidly changing loads without loss of efficiency.
11. The efficiency of the plant does not changes with age, where as there is considerable reduction in efficiency of thermal as well as nuclear power plant with age
12. Auxiliaries needed in the plant are less as compared to steam plant of equal size.
13. The cost per unit generator is low as compared to thermal (or) nuclear energy.
Disadvantages of hydro power plant
1. Initial cost of the plant including the cost of dam is high.
2. It takes long time for its construction (nearly 10-15 years) as compared to thermal plants (3-5 years).
3. The site selected for Hydel power plant is selected on the basis of water availability at economical head. Hence these are almost away from the load centers cases these require long transmission lines to deliver power. Therefore, the cost of transmission lines and losses in the lines will be more.
4. Power generation by the hydro-plant is only dependent on the quantity of water available, which in turn depends on rain. During the dry year, the power production may be discontinued. Hence the power from these plants is not much reliable.
5. For errection of hydro-stations requires special site properties. Hence these are located in isolated areas (or) Hilly areas. Therefore, the transportation facility is very difficult
0 Comments