The national grid

Question 1

describe how electricity is distributed in the national grid.

Answer 1

firstly, the power stations

Question 2

recap:
how do we generate electricity in the UK?
use percentages

Answer 2

over 50% comes from burning fossil fuels
25% comes from renewables (wind power etc)
20% comes from nuclear power
the remained is imported from europe

Question 3

what does the electricity have to do?

how does it do it?

Answer 3

get from the power stations to around 25 million homes in the uk.
the national grid

Question 4

what does the national grid consist of?

Answer 4

a system of transformers and high voltage cables

Question 5

name all parts that are involved in the national grid

name parts that are actually part of the national grid

Answer 5

power station
step up transformer 
high voltage power cables
step down transformer
homes

step up transformers
step down transformers
high voltage cables

Question 6

what is the national grids main job to do

Answer 6

connect electricity from the power stations to our homes

Question 7

what parts are actually called the national grid?

Answer 7

the transformers and the cables

Question 8

what is a really big problem getting electricity to homes?

what can we do to reduce this problem?

Answer 8

energy is always LOST in the power cables due to the resistance of wires

energy loss can be reduced by building power stations near to homes(but ppl don’t rlly wanna live next to power stations)

energy loss can be reduced by using transformers

Question 9

what part in the national grid is energy lost?

Answer 9

in the power cables

Question 10

why is energy always lost in the power cables

Answer 10

due to the resistance of the wires

Question 11

what increases the energy loss in the power cables from the power stations to our homes?

Answer 11

the bigger the distance between the power station and the homes, the greater the energy loss

Question 12

explain how we can reduce energy lost in the power cables using transformers.

Answer 12

First the electricity passes through the step up transformers which increase the PD to several hundred thousand volts

less ENERGY is lost in the power cables when the pd is very high
(the step up transformer increases volts)

The electricity passes through high voltage cables and to step down transformers

Question 13

what do we say in the exam to get a mark if asked what is lost in the cables?

Answer 13

ENERGY is lost

we do NOT say electricity is lost or we WONT get the mark

Question 14

why can’t the power cables pass the electricity to our homes?
what is this passed onto ?

Answer 14

because the Pd will be far too high

it passes through step down transformers which reduce the pd to around 230V

Question 15

what do step down transformers do?

Answer 15

when electricity is passed from the power cables to the step down transformers
it reduces the pd to around 230V
this is then passed to homes

Question 16

what do step up transformers do?

what do step down transformers do?

Answer 16

increase the PD to reduce energy loss in the transmission cables.
Reduce the PD before the electricity passes to homes