If why are there transformers that step up the voltage exiting power plants?

Answer 1

Transmission lines have resistance. Higher voltage can "push" more current through them, thus delivering more power to the consumer.

Another Answer

The power supplied (i.e. the rate at which energy is supplied) by an electricity transmission line is determined by the load NOT, as insinuated by the original answer, by the supply.

For a given load, the greater the supply voltage, the LOWER the resulting load current. So Transformers are used at power stations to increase the transmission voltage in order to MINIMISE the current (not to 'push more current through'!).

Electricity transmission is only possible because of high voltages causing a reduction in the load current, because, otherwise, the resulting voltage drop in the line would be far too great to supply distant loads.

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Answer 2

The higher voltage makes the transfer of power more efficient over long distances. The transformer near your house lowers the voltage to a usable level. If it weren't so tricky and dangerous to work with in a household setting, the higher voltage would still be more efficient even there.

Answer 3

Electricity is first generated at the Generation Station (GS) at approximately 13.8 KV in three phases (depending on the type of generator), KV being thousand volts. Then it is delivered to a Transmission Station (TS) (usually located near to the generation station) where this voltage is raised using a transformer to levels ranging from 115 KV to 800 KV and up. The voltage level depends on the distance being transported. Higher voltage levels are used for longer distances because there are less losses. Then after being transported long distances it enters a Distribution Station (DS) where the voltage is now lowered to 7.2 KV - 30 KV generally. DS's are usually located not too far from your house since lower voltages are not used to transport power very far. Then usually at the end of you drive way there will be a single phase transformer connected to one of the three phases that will further lower the 7.2 KV down to 120/240 V that is used in you house. This is just a VERY brief overview of how electricity gets to your house. In reality it is much more complicated but this should give you a general understanding.

Answer 4

Electric power plants raise the voltage that leaves them in order to decrease the required current for an equivalent amount of power. This reduces the required size of the conductors in the transmission and distribution wires. At the service transformer in the street or in the vault that higher voltage is stepped back down to the levels required for your home.

Answer 5

Because the loss of energy in the transmission cables ... energy that the utility

company generates or buys but loses before they can sell it ... is greater at low

voltage/high current, and less at high voltage/low current.