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John Williamson

wrote:
I don't really understand why we don't go for 3 phase at say 800V. Let's face it: even 230V is well into the lethal zone so going higher isn't going to be any more dangerous. Plus 800 is still low enough not to arc or flashover - given remotely adequate insulation. And just think of the saving in terms of conductor! Given the price of copper (notwithstanding it's slipped back lately) I'd have thought pushing up the supply voltages would be obvious thing to do from the pov of conserving natural resources.

One problem is the huge installed base of equipment, including cable
that is rated at the current voltages. Current insulation standards
sometimes stuggle with the current voltages, shown by exploding cables
as frequently reported in this newsgroup.

Another reason is that along every street in the country is a set of
three cables carrying the current voltages of 230V to earth, and 400V
(+-) between them. To have 800V available, the powers that be would need
to run new cables from new substations to only those users wanting 800V.

Another way to save money on the grid would be to increase the
frequency, allowing the use of smaller transformers for the same power.
The same objections apply, although aerospace applications often use
400Hz AC for this reason.

--
Tciao for Now!

John.