søn. 27. dec. 2020 19.00 skrev Valdis Klētnieks <valdis.kletnieks@vt.edu>:
On Sun, 27 Dec 2020 17:57:17 +0100, Baldur Norddahl said:

> Here in the civilised world we bury the wires ;-)

Even the long-haul 765kv and up connections across the power grid?

In the US, they're out on towers for a reason - you can fly along them
in a helicopter and easily spot parts of cable that are degrading and need
repair because they glow brighter on an infrared scope...

(Plus, as Hurricane Sandy taught Manhattan, buried wires have their
own rather nasty failure modes....)

All of the 400V and 10 kV is buried. That means no wires along streets, anywhere. 

The long haul transmission network consists mostly of 150 kV and 400 kV lines. That has been partly buried, especially near and in cities. There was a project to have it all buried but was abandoned halfway due to cost. 

But then it is all fully redundant, so they will just power it down if it needs maintenance. My company is digging for FTTH and in the few cases we need to cross one of these bad guys, they will shut it for us while we are working. Nobody looses power of course. 

The 10 kV network is redundant too. We managed to hit those a few times.  That will cause a power interruption for 10 to 20 minutes until they reroute the power. I believe mostly for safety, they need to be sure that the damaged line will not become energized again. 

Regards 

Baldur