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