Download Transmission of Electricity

Transmission of Electricity
Learning Outcomes
• Understand the need for an electrical distribution system
Physics 1
GCSE Science A
• Describe the national grid in terms of power stations,
substations, and power lines.
Transmission of Electricity
Key Words:
• Voltage: A type of electrical pressure, the “push” provided by
a battery in a circuit.
• Current: The rate of flow of electricity
Physics 1
GCSE Science A
• Transformer: A device used to change the voltage in a circuit.
Physics 1
GCSE Science A
Transmission of Electricity
It would be a lot simpler if one
power station met the electricity
needs of all houses in the country,
but what would be the problem with
this plan?
Physics 1
GCSE Science A
Transmission of Electricity
The National Grid is a network of
power cables, power stations, and
transformers, around Britain.
The National Grid connects
all the power stations, and
supplies electricity to all our
houses and factories.
Physics 1
GCSE Science A
Transmission of Electricity
Therefore, if something goes
wrong with one or more of the
power stations, it is possible to
get electricity from another
source.
Electricity is produced in the form
of Alternating Current (A.C.). It is
not possible to store this, therefore
the supply has to answer the
demand at all times.
Physics 1
GCSE Science A
Transmission of Electricity
How does a light bulb work??
Transmission of Electricity
Physics 1
GCSE Science A
Why don’t power lines glow?
How does a light bulb work??
Transmission of Electricity
Power station
houses
transformer
275 000V or
400 000V
As electric current flows through
a wire, some energy is lost as
heat – the higher the current
the more heat is lost.
Physics 1
GCSE Science A
25 000V
transformer
Because of the
relationship between
electrical power, current
and voltage, for the
same power, if a small
current is needed,
then the voltage will
be large.
Explain why this is a problem for companies producing electricity.
How do they address this problem?
Label the transformers – one raises the voltage, the other reduces it.
240V