Re: copper v ali
Overhead line suffer (significant) aolean vibration if the tension on the line is much above 20% UTS of the wire.
this vibration has an amplitude of a few 10's of mm and a wavelength in the order of a few m, with a frequency of the order of 10hz. (the actual sums are horror stories Eigen this and Reynolds that) - quite hard to see from the ground, but easy to spot when a line that should last 40 years fails in 6 months.
the also gallop - huge low frequency ocillations couple of m in amplitude, and 10's to 100's in wavelength.
We can (sort of) design out aolean but galloping is more problematic
ASCR (steel core) wires are sooooo 1970, it's all AAAC - All Aluminium Alloy Conductor (except for the HTLS types, but thay are still rare-ish ) these days. ACSR was not used to save cost. the alloys of ali to do the job did not exist. As soon as they did, we used them. Grid has/had a massive restring program to replace all the quad zebra lines (ACSR) with triple Aurucaria (AAAC) - you may notice as you drive round, some overhead lines have 3 wires per phase and skinny insulators, some have 2 or 4 wires and big ol' porcelain or glass insulators
towers are under tension, anything under tension vibrates
terminations on OHL's occur twice per phase (4 times if you count the non-tension joints of the jumpers) at every angle in the line - typically every few km, often less
(i'll not pass comment on either the training or expertise of my linesmen :-D)
If you consider the implications of the point above, you will see that in fact I do have some experience with high current terminations. 100A into a starter motor is not going to keep me up at night considering I work on 3.5kA UHV terminations by day (potentially 60kA under fault for a few seconds). In reality it's just like any other electro/mechanical connection. you need to keep things clean, and use the correct tools... correctly
If you read my op you will not I did point out that using ali just made the wire harder to use - thicker and stiffer (we sometimes used copper conductors in distribution too-it's a nightmare - but that's all about tension, so does not apply here) the resistance per unit length & mass ratios are very similar, but LME prices make ali preferred, but that's only important if you are buying of tons of the stuff at a time.