National Grids Flashcards
What is a national grid?
It is a network of cables, power stations and transformers that distributes electricity to our homes
What do step up transformers do?
They step-up the voltage from the power station before it reaches the cables on national grid. This reduces the current in the cables and so reduces energy loss
What do step-down transformers do?
They step-down the voltage to a safe level so that it can be used in our homes
Why do some people dislike electricity pylons?
Because they say they spoil the landscape and it can effect peoples health (because of the electric and magnetic fields)
What are the disadvantages of underground cables?
They are more expensive
Much more difficult to repair
Difficult to burry where they cross canals, rivers and roads
What are the advantages of underground cables?
create less visual and environmental impact (which is a large opposition from local communities)
have lower maintenance costs;
are less susceptible to the impacts of severe weather.
What are the advantages of overground cables?
Overhead power cables are cheaper to install and maintain
They are also quicker to fix whenever faults develop.
What are the disadvantages of overground cables?
they are more susceptible to damage, and many people do not like the way they look.
Ugly
What are transformers and what do they do?
Transformers are part of the National Grid. A transformer is an electrical device that changes the voltage of an AC supply. A transformer changes a high-voltage supply into a low-voltage one, or vice versa.
A transformer that increases the voltage is called a step-up transformer
A transformer that decreases the voltage is called a step-down transformer
Why are transformers important?
Because they reduce energy losses in the cables
How is electricity distributed?
From power stations to consumers along the national grid
What happens is you increase the voltage?
You reduce the current required and this reduces the energy loss in the cables
