On 19/12/2020 04:35, The Natural Philosopher wrote:
On 18/12/2020 13:25, newshound wrote:
I don't think winds normally cause too much problem on 11kV.

Then you are wrong. Especially near trees. Mind you in the last 20 years
they have cut nearly all the trees back near thenm round here, which has
helped, but gales still cause brownouts


Trouble is, they don't produce enough corona discharge to keep birds
clear.

Neither do teh 275Kv ones, Ive seen birds on those.

On national transmission lines the current they can carry is limited
by sag caused by thermal expansion, so they can carry more power at
low temperatures. A rare example of Sod getting it wrong.

I don't think that is correct either. There isn't much sag before
melting on a hot wire.

Yes there is. I spent most of my childhood on the farm behind where
I lived and there were a number of ?132Kv pylon routes passing through
their fields and on a hot August day it was very noticible that the
wires were closer the ground than in winter.


In reality losses get too great at high currents - I²R etc etc.