Recently in the local rag was an article re increasing the line temperature from 70° C to 120° C on the 220 kV lines from Transpower Penrose to TP Albany, New Zealand.
This is a stretch of about 50 kM, (32 Miles)

Transpower was asking for resource consent because of the extra sagging of the wires. The MAD's would still be acceptable.

We have an ageing network within the country which needs urgent upgrading in some area's but with the privatisation things get delayed even more and profits diappear in managers pockets.

Work out the powerlosses in those lines.

This is a double circuit 220 kV line with 2 wires in parallel on each phase.

I have seen in Europe 3 and 4 wires in parallel on high current circuits. Probably extra weight will require heavier pylons and doubling up of insulators.

Whats the situation overseas ? Similar suggestions from the distribution companies ?

I think with those temperature the tensile strength of the aluminium and (steel) conductors and crimps will get stressed and may cause early faillure perhaps

Ray,
I would imagine that engineers in most other countries would have upgraded the Transmission system, long ago like they were supposed to here.
It probably would have happened too,but the public were unable to decide who was going to have the lines near thier properties.

Well, the losses over 50 km should be pretty small at the voltage level involved.

I've heard of plans in other countries to raise conductor temperature for certain "bottlenecks" in the grid. There appears to be new high temperature conductors on the market, but I take it from your post that they intend to use the existing conductors?

Off topic: The electricy generation situation in Sweden just took the strangest of turns. A dozen industrial buyers created their own power company to get a better price. They agreed with the Russians to build a 1 GW subsea cable to the Leningrad reactors.

Quote:
"Similar suggestions from the distribution companies ?"

Move to Texas if you build transmission lines. It is unique in that the governing body, ERCOT (Electric Reliability Council Of Texas) is entirely within the state. When we deregulated, all transmission expenses are paid out of a pool called T-costs. It didn't take long for the Utilities to realize you could double the price of everything and build a solid gold transmission line since the cost would be distributed state wide.
(Of course, we all know it wasn't built of gold and the money went somewhere else).

It comes under the heading of, "What the consumer doesn't know won't hurt him".

Of course, the land condemnations and various legal red tape usually take so long that the line is overloaded by the time they finish building it.

These higher wire temperatures are for the existing ± 30 year old conductors, which are within the greater Auckland area.

The next step will be the line to Huntly which is an other 60 km's of 220 kV.