Transcript Transmission of electricity 1 part 2

Transmission of Electricity
When energy is transferred at a high voltage, it uses a lower current, which
results in less energy being lost as heat in the cables.
The National Grid has to transmit electricity over large distances.
But at 400kV, only 1% of the energy will be lost as heat.
Physics 1
GCSE Science A
Step-uptransformer
If the National Grid was to
transmit at 25,000kV from the
power station, about 40% of
the electrical energy would be
lost as heat – the electricity
would be expensive as a result.
This would also mean that the tall pylons could carry thinner, lighter wires, thus
making them cheaper.
Transmission of Electricity
• We need an electrical distribution system so that if one power station has
to shut down, or if there is a problem, other power stations can take its
place.
•Step down transformers are used to lower the voltage of the electricity
before it’s used in homes. This makes it safer to use in homes.
Physics 1
GCSE Science A
•Step up transformers are used to increase the voltage of the electricity
before it is transmitted, this prevents energy being lost as heat.
Transmission of Electricity
A network of 1500
buoys floating freely in
the Irish Sea giving us
a long term view of the
weather.
BBC
ITV
S4C
National Grid
computers
The need for
electricity is greater
in the winter than in
the summer
Physics 1
GCSE Science A
Information from
sensors
throughout the
country about
weather.
Television companies sending data
estimating the number of audience
expected.
Click here to view the electricity
demands of Britain at this
moment.
National Grid
Need
Transmission of Electricity
The graph below shows the use of electricity across Britain over a one week
period.
Click on the arrow
to move the graph
47000
National Grid usage ( MW)
42000
37000
32000
27000
Fr
Sa
Su
Mo
Tu
We
Days of the week
Th
Fr
Try and describe the shape of the graph – is there a pattern?
The graph shows a maximum and minimum amount for each day. Estimate the
times where these values occur.
What makes the weekends so different?
Sa
Click here for
more data
What does the above graph tell us about the use of electricity in Britain?
Physics 1
GCSE Science A
22000
Transmission of Electricity
Use of NATIONAL Grid (×1000 MW)
Physics 1
GCSE Science A
Below is a graph of electricity use during one of the World Cup football
games. Drag the labels to their correct locations.
Time
Kick off
Half time
Full time
End of
extra time
After the
penalty
shootout
Click here for
the answer
Transmission of Electricity
Below is a graph of electricity use during one of the World Cup football
games. Drag the labels to their correct locations.
Kick off
After the
penalty
shootout
Half time
Use of National Grid (×1000 MW)
Physics 1
GCSE Science A
Full time
End of
extra time
Time
Transmission of Electricity
• We need an electrical distribution system so that if one power station has
to shut down, or if there is a problem, other power stations can take its
place.
•Step down transformers are used to lower the voltage of the electricity
before it’s used in homes. This makes it safer to use in homes.
Physics 1
GCSE Science A
•Step up transformers are used to increase the voltage of the electricity
before it is transmitted, this prevents energy being lost as heat.
•The energy supply must be constantly monitored so that it meets
fluctuating demand! We can’t store the energy that’s generated in a giant
battery.
Transmission of Electricity
Physics 1
GCSE Science A
You are the scientific advisor to
the government. You have to
explain to the Prime Minister
David Cameron why we can’t
just have one large power
station supplying electricity to
the whole country.
Mr Cameron hasn’t studied Science for
a good few years so you shall have to
be thorough in your explanations.
(Some people also think he’s an idiot)