Generating And Distributing Electricity Flashcards
how is most of the electricity we use created now
- burning fossil fuels in the boilers of big power stations
- burning fuel is used to heat water to turn it to steam
- the steam turns a turbine
what is the turbine in a power station connected to
- a powerful magnet inside a generator
- which is a huge cylinder wound with coils of copper wire
what happens when the turbine spins in relation to the magnet inside the genrator
- the magnet spins with it
- producing a large potential difference
- and alternating current in the coils
how is a single output generated from the generator regarding the coils
the coils are joined together in parallel
what is another example of how a turbine and generator set up is used to generate electricity and how does that work
- producing electricity using hydroelectric methods
- the tidal and wind power turn the turbine directly
- without needing to turn water into steam first
what is the only power generator that doesn’t use a turbine and generator system
solar
where does the generated electricity go to after and what is it
- it goes to the national grid
- which is a network of wires and transformers that connects UK power supplies to consumers
why does the national grid transmit energy at a high power
- because it had to transfer loads of energy each second
- shown by power = energy transferred / time taken
why does the national grid either need a high potential difference or high current
- because electrical power = potential difference x current
- so to transmit the huge amounts of power needed, you need a high pd or current
why does the national grid use high voltage, low current, transformers and low resistant cables rather than high current cables even though they would equal the same electrical energy
- because a high current causes the wire to heat up
- which loses a lot of energy to the thermal energy stores
- power is also lost due to resistive heating
- found using electrical power = current^2 x resistance
why is the input power equal to the output power in transformers
because they are almost 100% efficient
if transformers are almost 100% efficient, what does it allow the national gird to do when maintaining the same electrical power
- you can increase the potential difference across a coil
- and also reduce the current through it
what do step up transformers in power stations do
they boost the potential difference really high (400k) and keep the current low
what do step down transformers in power stations do
bring the potential difference back down to safe and usable levels at the consumer’s end
what is the ratio between the potential difference of the primary and secondary coils of a transformer the same as
the ratio of the number of turns in the coils
