David Nebenzahl wrote:
On 6/1/2008 3:53 PM Tony Hwang spake thus:

George wrote:



DC high voltage transmission lines have lower losses and are less
expensive to build. They use solid state convertors at each end. 500
kV was the max for a while and I know the Canadians have a line in
service for at least 20 years that operates at 735 kV DC and I read
that the Chinese recently started construction of a 800 kV DC
transmission line.


Prove it with simple Ohm's law. If it is HV, how heavy is the cable
gonna be?


So far as that goes, keep in mind that as the voltage increases, the
size of the conductors needed to carry the electricity decreases (that's
one reason long-distance transmission lines are HV). So you can either
increase the size of the conductors, or step the voltage up using
existing conductors.


.... keeping in mind that the insulators will also need to be up to the
task presented by the increased voltage. :-)

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