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Electricity
and the National Grid
Question | Answer |
---|---|
what is the National Grid? | is the network of pylons and cables that cover Britain, getting electricity to homes everywhere. it takes electrical energy from power stations to where its needed in homes and industry |
how do you transmit the huge amount of power needed? | you need either a high voltage or a high current |
what is the problem with a high current? | you lose loads of energy through heat cables. its much cheaper to boost the voltage up really high (400 000 v)and keep the the current very low |
how do you get the voltage to 400 000 v? | it requires transformers and big pylons with huge insulators |
what do the transformers do? | they have to step the voltage up (step up)at one end for efficient transmission and then bring it back down to safe levels at the other end (step-down) |
how is the voltage increased? | using a step up transformer |
how is the voltage reduced? | using a step down transformer |
what are the advantages of overhead cables? | - lower setup costs - easy to access - easy to setup - minimal disturbance to land |
what are the disadvantage of overhead cables? | - lots of maintenance needed - ugly - affected by the weather - less reliable |
what are the advantages of underground cables? | - minimal maintenance - hidden - not affected by weather - more reliable |
what are the disadvantages of underground cables? | - higher set up cost - hard to access - hard to set up - lots of disturbance to land |
what is the National Grid? | is the network of pylons and cables that cover Britain, getting electricity to homes everywhere. it takes electrical energy from power stations to where its needed in homes and industry |
how do you transmit the huge amount of power needed? | you need either a high voltage or a high current |
what is the problem with a high current? | you lose loads of energy through heat cables. its much cheaper to boost the voltage up really high (400 000 v)and keep the the current very low |
how do you get the voltage to 400 000 v? | it requires transformers and big pylons with huge insulators |
what do the transformers do? | they have to step the voltage up (step up)at one end for efficient transmission and then bring it back down to safe levels at the other end (step-down) |
how is the voltage increased? | using a step up transformer |
how is the voltage reduced? | using a step down transformer |
what are the advantages of overhead cables? | - lower setup costs - easy to access - easy to setup - minimal disturbance to land |
what are the disadvantage of overhead cables? | - lots of maintenance needed - ugly - affected by the weather - less reliable |
what are the advantages of underground cables? | - minimal maintenance - hidden - not affected by weather - more reliable |
what are the disadvantages of underground cables? | - higher set up cost - hard to access - hard to set up - lots of disturbance to land |