If most of the electronic devices nowaday works on DC then why we prefer AC transmission and distribution ?
Answers
Explanation:
Electricity is generated and transmitted in AC because in the early development of electrical distribution, it wasn’t possible to boost DC voltages for long distance transmission. Also, alternators (AC generators) are relatively inexpensive to make and maintain compared to DC generators.
If Thomas Edison had his way, there would be a small generating station in every neighborhood supplying DC power at low voltages (around 120 volts).
It’s much more economical to generate power at a large scale; that’s why we have huge centralized generating stations with the capacity to serve thousands of customers. Being able to transmit power over long distance with minimal resistance loss is important, and that is most easily done by boosting the voltage.
Boosting AC voltage is easy with the use of transformers, which are basically insulated wire wrapped around an iron core. Not a very complex device at all. Boosting DC voltage requires sophisticated electronics, which becomes complex and expensive at extremely high power levels.
(You can also decrease resistance losses by increasing the wire size. To convert the existing grid to a single voltage — 120V or 240V — would require transmission lines to have wires impossibly large. Boosting voltage is the only practical way to transmit large amounts of power long distances.)
We can now boost DC voltages, and for extreme long distance transmission (linking power grids) that’s the technology that’s used because inductive losses are much less than in AC transmission lines. However, DC voltage conversion equipment is still much more complex and expensive than AC voltage conversion equipment.
So we transmit electricity in AC because it allows efficient, centralized generation and transmission of power over long distances, and that could only be done with AC during the early development of power distribution.
In a sense, “we do it that way because we’ve always done it that way.” If you were building an entirely new grid today, you might be able to leverage current technology and go for an entirely DC system with DC generation, transmission, and household appliances, and it might be more efficient in some ways. It wouldn’t be cheaper to implement. And you’d have to replace trillions of dollars worth of perfectly functional equipment that’s designed only for AC use.