Introduction
In today’s blog we will learn about the Working of hydroelectric power plant, What is Pumped storage power plants, what are pumped storage schemes, Pumped storage power plant working
Working of hydroelectric power plant
To generate electricity from a hydroelectric power plant,
the primary requirement is water availability in huge quantities at the good head.
for completing this requirement, a dam or reservoir is constructed to maintain sufficient height.
If the natural reservoir is absent, we can create an artificial reservoir by constructing a dam on a river or lake.
pressure tunnel connects the reservoir to the valve house at the start of the penstock.
A valve house contains the main sluice valve and automatic isolating value.
The main sluice valve controls the water flow to a power station.
And the function of the automatic isolating valve is to cut off the supply in case of the bursting of the penstock.
A surge tank is placed before the valve house; the main function of this surge tank is better regulation of water pressure in the system
From the reservoir water is carried through pressure tunnel and from valve house to the water turbine through a pipe of large diameter made from steel or reinforced concrete. This assembly is known as a penstock.
The turbine, which is connected to the penstock, converts the hydraulic energy of water into mechanical energy.
This mechanical energy is given as an input to the alternator,
which finally gives us an electrical output, which is the main purpose behind a power plan.
After rotating the turbine and doing the useful work, water is discharged through a tailrace.
What is Pumped storage power plants
The pumped storage power plants are the unique design of peak load power plants.
A specialty of these plant types is that the plant pumps back or supplies a portion of its water during the low load period.
This plant is also known as a hydraulic accumulator system.
Pumped storage plants can use two types of assembly; the first is vertical shaft arrangement, and the second is horizontal shaft arrangement.
In older plants, there are separate motor-driven pumps and turbine-driven alternators are used. The technological improvement cause the pump and turbine to work on the same shaft with electrical element acting as either generator or motor.
what are pumped storage schemes
This type of plant is quite different; two water sources work as running fuel. One is the headwater pond situated at a proper height. This pond is connected through a penstock.
A generating pumping plant is situated at the lower end. At the same place, another lower headwater pond is there. This pond is also connected with the generating plant through a penstock.
The plant utilizes surplus energy generated by the baseload plant to pump the water from the tailwater pond into the headwater pond during off-peak hours.
Pumped storage power plant working
During the peak load period, this water is used to generate power by allowing it to flow from the headwater pond through the water turbine of this plant to the tailwater pond.
While in peak hours, the turbine drives the generator to produce electricity. During off-peak hours, the generator operates as a motor. But, first, it drives the turbine, which now works as a pump to raise the water from the tailwater pond to the headwater pond.
If you read the process carefully, you can observe that the water flow cycle is continuous and repeating itself during peak and off-peak loads.
Thus the same water is used, again and again, so the wastage of water is reduced in the case of these types of plants; extra water is required only to take care of evaporation and seepage.
The power for driving a generator as a motor is taken from the system.
This arrangement reduces the capital cost of the plant and increases efficiency, thus resulting in economic operation.
The capacity of the pond should be such that the plant can supply peak load for 4 to 10 hours.
