Why dams are called “the temples of modern India
The phrase "temples of modern India" was coined by Jawaharlal Nehru.
Nehru saw dams as symbols of India's progress and as tools for economic growth and social justice.
Nehru believed that dams would help to alleviate poverty in India by providing water for irrigation, hydropower, and domestic consumption.
He also saw dams as a way to modernize India's economy and improve infrastructure.
Dams seen as a way to harness India's vast water resources to promote economic growth.
The construction of dams in India began in the early 20th century.
It was during Nehru's time that the program really took off. Nehru oversaw the construction of several large dams, including the Bhakra Nangal Dam and the Hirakud Dam.
The Bhakra Nangal Dam is a hydroelectric dam on the Sutlej River in the Indian state of Punjab.
It is one of the largest dams in India and is the second-largest concrete dam in the world.
The Hirakud Dam is a multi-purpose dam on the Mahanadi River in the Indian state of Odisha.
It is the largest earthen dam in the world and is the third-largest dam in India by volume of water stored.
Nehru's vision of dams as "temples of modern India" has had a lasting impact on the country.
Dams continue to play a vital role in India's economy and society.
They provide water for irrigation, hydropower, and domestic consumption. They also help to regulate floods and prevent waterlogging.
What are the basics of transmitting electricity?
In any conductor that transports electric current.
The transmission efficiency is higher at lower current and higher voltage.
This is because the energy loss during transmission increases as the square of the current.
The amount of voltage increase corresponds on a 1:1 basis with the amount of current decreased.
If voltage is increased by five units, the amount of current will drop by five units, but the amount of energy lost will be reduced by 25 units.
Transformers increase the voltage and reduce the current before feeding into transmission lines, and the reverse when receiving current to be supplied to consumers.
Transmission cables can be seen transporting current at 115 kV, 230 kV,
More than 2,000 kV or so is infeasible because then air itself becomes conducting, causing the cable to ‘leak’ current.
The cables that move the current still have some resistance, which results in some energy loss.
All these factors are further complicated by the use of alternating current (AC).
AC can be modified more easily in transformers than direct currents (DC) and also has higher transmission efficiency.
What is AC power?
The most common way to transfer electric power is in the form of three-phase AC.
In AC, the voltage flips polarity.
The AC frequency is equal to the voltage flipping frequency.
Imagine this voltage change to be mapped to a circle: it completes one semi-circle (180°), from top to bottom, as it flips one way; when it flips the other way, it completes the other semi-circle (180°) and is back to its starting point.
In a three-phase AC circuit, there are three wires.
When current starts to follow in Wire A, the voltage is at 120°; in Wire B, it is 240°; and in Wire C, it is 360°.
All three wires transport AC power.
How is power transmitted?
In a three-phase AC circuit, each wire transmits an AC current in a different phase.
From a power station, the wires are routed to transformers that step-up their voltage.
Then, they are suspended from transmission towers, which must be stable and properly wired, as they travel long distances.
Insulators in contact with the wires draw away some current if there is a surge in the line.
Circuit-breakers ‘break’ the circuit if there is too much.
The towers are also grounded and equipped with arresters that prevent sudden increases in voltage.
Switches are used to control the availability of current and to move currents between different lines.
These wires eventually lead to and exit from different kinds of substations.
Converters modify the AC frequency.
Distribution substations step-down the voltage in power lines and prepare them for consumption.
Transmission substations merge or fork different lines and diagnose problems in different lines.
How do grids operate?
As mentioned earlier, transmission is situated between production and distribution.
A national grid includes all three components, and as a result transmission also has to account for the particulars of power production at different types of sources, at various locations, and how and where that power is consumed.
So grids also have storage facilities that store electrical energy when there’s a surplus supply and release it in times of deficit.
They are also connected to sources like gas turbines that can provide power on short notice, such as during emergencies, as well as automated systems that ‘tell’ sources to increase or decrease their output in response to fluctuating consumer demand.
Grids also need to respond to failure in different parts of the network and prevent them from carrying over to other parts, adjust voltages in response to demand (as well as manage demand), control the AC frequency, improve the power factor (the power drawn by a load versus the power available in a circuit), etc.
A grid becomes a wide-area synchronous grid if all the generators connected to it are producing an AC current at the same frequency.
The world’s largest such grid covers Azerbaijan, Belarus, Georgia, Kazakhstan, Kyrgyzstan, Mongolia, and Russia;
India’s national grid is also a wide-area synchronous grid.
Bhakra Nangal Dam – location
Bhakra Nangal Dam is a concrete gravity dam on the Satluj River in Bhakra Village near Bilaspur in Bilaspur district, Himachal Pradesh in northern India.
The dam forms the Gobind Sagar reservoir.
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