Hydroelectric Power Plant or Hydroelectric Power Station
Hydroelectric power is developed from Hydroelectric Power Plant or Hydroelectric Power Station. It develops hydroelectricity to utilize the potential energy of water. In hydroelectric power plant, water is stored in a dam called hydroelectric dam which is located upper level from the ground especially any hilly areas. Water head is created by construction the dam across any river or lake.This type of water head store huge potential energy. The water fall into water turbine and the potential energy of water is converted into kinetic energy. This kinetic energy is converted into mechanical energy at the turbine shaft. A hydroelectric generator or alternator is coupled with turbine shaft to convert mechanical energy into electrical energy. The power P is developed-
W = Specific weight of water in kg/m3
Q = Rate of flow of water in m3/s
H = Height of fall or head in meters
η = Overall efficiency of operation
Hydroelectric power plant is becoming very popular nowadays to full feel rapid increasing demand of electric power day by day. Every country is trying to develop more Hydro Electric Power Station to full fill their demand for electricity. In other hand fossils, fuels ( i.e. coal,oil, and gas) are limited stock in the world and these fuels are expensive. So hydroelectricity may be a good alternative electrical source. So in a single word we can say,a generating Station which utilizes the potential energy of high-level water for the generating of electrical energy is known as hydropower plant or hydroelectric power plant.
WORKING PRINCIPLE OF HYDROELECTRIC POWER PLANT
Working principle of hydroelectric power plant depends on the conversion of hydraulic energy into electrical energy. To get this hydroelectricity,hydroelectric power plant needs some arrangements for proper working and efficiency. The block diagram of hydroelectric power plant is shown below:
Hydroelectric power station needs huge amount of water at sufficient head all the time. So a hydroelectric dam is constructed across the river or lake.an artificial storage reservoir where water is stored, is placed back side of the dam. This reservoir creates sufficient water head. A pressure tunnel is placed in between the reservoir to valve house and water is coming from reservoir to penstock via this tunnel. An automatic controlling sluice valve is placed in valve house and it controls water flow to the power station and the letter cuts off supply of water in case the penstock bursts. Penstock is a huge steel pipe in which water is taken from valve house to turbine. A surge tank is also provided just before the valve house for better regulation of water pressure in the system. Now water turbine converts hydraulic energy into mechanical energy and an alternator which is couple to the water turbine converts this mechanical energy into electrical energy.
ADVANTAGES & DISADVANTAGES OF HYDROELECTRIC POWER PLANT
There are lots of advantages in Hydroelectric Power Plant:
1. Since water is the main source of energy,so no fossil fuels are required.
2.This plant is neat and clean and no smoke or as disposal is required.
3.It is the cheapest operating and maintenance cost as compared to the other power plants because water is freely available in the world.
4.It is very reliable, robust and has a longer life app rocks 45 to 60 years.
5.This plant can start instantly.
6.It can start hydroelectric power with fluctuating load demand.
7.The efficiency does not fall at the age of this plant.
8.There is no standby loss in this plant.
9.At the initial time of construction highly skilled engineers are required and after that only few experience persons can run the plant.
10.This plant also serves to help in irrigation and Flood control etc.
11.Since this plants are located remote area so land is available and competitively cheaper rates.
There are some Disadvantages in hydro power plant:
1.Such plant requires large area
2.High construction cost is required due to construction of dam.
3.When experience skilled engineers are required to build this plant
4.Scenes such plant is located as from the load areas, long transmission line is required to transmit this hydroelectric power.
5.It doesn't supply constant hydroelectricity due to the availability of water. In transition, power supply is most affected.
SITE SELECTION FOR HYDROELECTRIC POWER PLANT
Main fuel of this plant is water.So, such plant should be located nearer to river,canal etc. where sufficient water is available all the time.
Storage of water in a suitable reservoir or dam has to be placed by a careful geological study of the area to get the maximum advantage of that water.Dam should be located across the river to get continuous water supply throughout the year specially in a dry season.The storage capacity of dam can be determined by hydrograph or mass curve or using analytical method.Adequate facilities of erection a dam and storage of water are two important matters for site selection of hydro electric power plant.
It is an important point for site selection of hydroelectric power plant.Water head is directly related to the cost of generation of electric power.If effective head is increased,water storage has to be reduced as well as capital cost of the plant is reduced.
4.Distance from the load center:
Since it is located away from the load center, more transmission line is required to supply the power.To avoid the line loss and economical power supply, distance of such plant should need more attention.
Good transportation facilities must be available to any hydro electric power plant, so that necessary equipment should be reached easily.
6.Availability of land:
Hydro electric power plant needs enough space.It should be kept in mind that land cost must be cheap.Read More Questions Click here