Why AC instead of DC for Electric Power Transmission?

Smythe

Q. Explain why A.C. is used instead of D.C. to transfer electrical power from the generating station to the consumer.

A. To reduce the energy lost in long distance transmission. To reduce costs involved in transferring electrical power over long distances.



Above is the answer which I provided to this question in my mock exam, though the teacher said it wasn't specific enough and my answer should have included something about

a) high voltage, low current
b) transformers need changing magnetic fields

Was wondering if anyone could help with including these? So I know for future reference. Thanks very much

FISMA

Your teacher was correct, you need to be a bit more specific.

Go to youtube and have a look at this
http://www.youtube.com/watch?v=aaAHq1yh1vk&feature=related
at about 1:05 you will see a bit about what you are referring to.

Basically, in DC circuits, charge has to flow great distances. In AC, charge flows a small distance, back and forth.

The greater distance means that the electrons that drift will encounter more resistance on the surface of the conductor. More resistance = more loss.

Check out the entire Tesla show.

Smythe

Thanks very much FISMA, I'll take a look at that now.