The hydroelectric power plant utilizes the potential energy of water to convert electrical energy.
In a hydropower plant, the gravitational force of water is used to run the turbine which is coupled with an electric generator to produce electricity. Hydroelectric power stations are generally located in hilly areas because in this area the dam can build conveniently with the head as well as produce a high amount of potential energy. From the dam, water is fed to a water turbine in form of potential energy and then is converted into mechanical energy than by using a generator electricity is produced.
Advantages of Hydro Power Plant:
(i) It requires no fuel as water is used for the generation of electrical energy.
(ii) It is neat and clean as no smoke or ash is produced.
(iii) It requires a very small running cost because water is available at free of cost.
(iv) It is comparatively simple in construction and requires less maintenance.
(v) It does not require a long starting.
(vi) It has a longer life.
(vii) The dam also helps in irrigation and controlling floods.
Disadvantages of Hydro Power Plant:
(i) It required much capital cost for the construction of the dam.
(ii) The availability of water depends on weather conditions.
(iii) It requires a high cost of transmission lines as the plant is located in hilly areas which are away from the consumers.
Schematic Arrangement of Hydro-electric Power Station:
In a hydropower plant, hydraulic energy is converted into electrical energy by the different arrangements of the component. The schematic arrangement of a modern hydroelectric plant is shown in Fig below.
Some of the major components in hydroelectric power plants are following
- Reservoirs,
- Dam,
- Surge Tank,
- Penstock,
- Spillway,
- Generator etc
The functions of all major components are discussed.
Reservoir:
The main function of the reservoir is to store the water during the rainy season and supply this stored water during the dry season. This is in a simple, water storage area.
Dam:
The main function of the dam has increased the head of the power plant to increase the potential energy behind it which increases the reservoir capacity. Building a dam also plays a great role in agriculture's purpose through irrigation.
Surge Tank:
The main function of a surge tank is to reduce the water hammering effect.
Penstock:
The penstock is a pipe between the surge tank and the prime mover. The structural design of the penstock is the same as for any other pipe except it has to bear high pressure on the inside surface during the sudden decrease in the load and increase in the load. Penstocks are made of steel through reinforced concrete.
Spillway:
The function of the spillway is to provide safety for the dam.