[LINK] Power Transmission 101

[Tom Koltai]

OK, found one.... (a teaching resource) not half bad if you  leave it
running for a while...

http://tcipg.mste.illinois.edu/applet/The+Power+Grid

Quote/
The power grid is the system of producers and consumers of electricity.
It includes power generators, the users of electricity, switches that
control the electricity, and the system of substations, power lines, and
transformers that deliver the electricity. A community might have a
generator to provide its power. The generator may be able to vary its
production as the usage of the customers changes, but there may be times
when the demand for energy is too great for the generator. Then the
community buys electricity from another source. At other times, the
generator may be making more electricity than the community is using, so
it wants to sell it. 
/Quote