the nationsl grid

What is the national grid and what does it do

The national grid is a giant system of cables and transformers and connects power stations to consumers

It transfers electrical power from power stations from supply to demand

When does electricity demand peak normally

During late afternoon

How do power stations cope with high demand

Power stations need to have spare capacity so often they run way below maximum power output

What do you need to transmit a huge amount of power

You need either high potential difference or high current

What is the problem with needed high current to transmit a huge amount of power

High current loses loads of energy to surroundings

How do you avoid losing loads of energy from high current

Need to keep current very low meaning voltage will have to be very high which means once the electricity is already generated in power stations we need to increase voltage before sending to country

How do you increase voltage for power stations

by using a step up transformer which increases voltage to around 400,000 V. The wire then transmits the electricity all across the country between two pylons and before reaching destination the voltage has to be reduced back down again using a step down transformer lowering it to 230 V

Why does the voltage need to be lowered before sending to destination

• High voltage is dangerous

• It will blow up appliances in houses