it is s network of transformers linking power stations to consumers although pylons carry the cables, they are not considered to be part of the national grid.
what are transformers?
they are devices that change the size of an alternating PD. step up transformers increase the PD
step down transformers decrease the PD.
power = current x pd. so if pd increases current must decrease because power is constant.
why does the national grid use a high potential difference and a low current?
to transmit the amount of power needed, a high pd or high current is required
however, lots of energy would be lost through heat
it is cheaper to boost the pd and keep the current low
increasing the pd increases the current which decreases the energy lost through heating. this is more efficient
