Power stations are usually situated large distances from cities where most of the consumers are located. This presents problems with power lossesin the transmission lines. Transmission lines are essentially long metallic conductors which have significant resistance. This means that they have asignificant voltage drop across them when they carry a large current.This could result in greatly decreased voltages available to the consumer.
The solutionis to use transformers to step up the voltage before transmission. If the voltage is increased, the current is reduced. Recall that the power lost in transmission lines is given by the formula:
P(loss) = I^2 R.
If the transmission voltage is doubled, the current is halved and the power loss is reduced by a factor of four. If the current is reduced by a factor of 10, the power loss is reduced by a factor of 100, and so on.
Using transformers enables electricity to be supplied over large distances without wasting too much electrical energy. This has had a significant effect on society. If transformers were not used in the power distribution system, either power stations would have to be built in the cities and towns or the users of electricity would have to be located near the power stations. The latter would mean that industries and population centres would have to be located near the energy sources such as hydro-electric dams and coal mines. The former would mean that fossil fuel stations would dump their pollution on the near-by population centres.
CREDITS: Text Book.