AC Production and Transmission

AC Production

An Alternating Current (AC) changes direction regularly and periodically.
In the UK, the standard AC frequency is 50Hz, meaning the current changes direction 50 times every second.
AC can be represented graphically as a sine wave.
AC is produced by generators in power stations. These use the principle of electromagnetic induction.

Electromagnetic Induction is the process of generating an electric current from a changing magnetic field.
Changes in magnetic field can be caused by relative motion between a coil and a magnet.
This is where a voltage, or Electromotive Force (EMF), is induced which causes current to flow.

Generators convert mechanical energy into electrical energy.
They work on the principle of electromagnetic induction, where a coil is rotated within a magnetic field or vice versa.
The coil’s motion within the magnetic field induces a voltage, which leads to the flow of AC.

A Transformer is used to change the voltage of an electric current.
Transformers make long-distance transmission of AC more efficient, by stepping up the voltage to reduce heat loss in the cables.
They can step up or step down voltage, depending on requirements at different stages of power transmission.

AC can be easily converted between different voltage levels using transformers, making it more suitable for long distance transmission.
Transmission at high voltage and low current minimises energy loss due to the heating effect.
Electricity grids worldwide use AC because it is safer to transfer over longer distances.

Most Power Grids use a mixture of overhead and underground cables to distribute electricity.
Power is carried at high voltages from power stations and is stepped down to safe, usable levels for homes and businesses.
Transformers are utilised at various points in the grid to ensure efficient transmission and distribution.
Electrical energy can be lost in the process due to resistance in the wires, causing them to warm up. This is why high voltage is used for transmission.