Cost reduction is one of the major challenges for Network Rail, the owner and infrastructure manager of most of the rail network in England, Scotland and Wales. Engineers are working on a range of ways in which costs can be reduced, and the electrical fraternity is playing its part.
One of the best cost reduction measures is to remove copper from power cables altogether and substitute them with another conductive metal, aluminium, which is cheaper at around £1.50 a kilo.
“We can’t get rid of copper by just replacing it with aluminium,” said Nigel Edwards, professional head of power distribution HV/LV at Network Rail. “That’s what’s different about this work stream. It’s a complete system overhaul that allows us to look at the wider implications of the removal of copper.”
The proposed solution of Network Rail includes a new, enhanced, unarmoured aluminium cable constructed of either solid or stranded conductors with integral water blocking. This is a brand new process designed to withstand challenges associated with aluminium cable.
The use of cables with aluminium conductors has been very scarce in commercial and domestic premises. The major users of aluminium cables are the electricity generation, transmission and distribution companies and railways. Presently, three major Electricity distribution companies in UK use aluminium rather than copper for all of their new low- voltage cable distribution systems.
When aluminium house wiring cables were introduced in the USA, they were not introduced as a complete system with joints and terminations specifically designed for use with aluminium cables; instead, aluminium cables were used with the existing accessories that were designed for use with copper cables which resulted in performance failure.
The resistance of a cable with an aluminium conductor will be approximately 1.6 times that of a cable with a copper conductor. Interestingly, a like for like equivalent size of aluminium cable is still 50 per cent cheaper than a copper equivalent.
Network Rail has specified process of replacing copper conductors with aluminium conductor cables. According to them, if an aluminium cable is used to replace a copper cable, the conductor size has to be increased by one or two standard sizes. The basic design is same for copper and aluminium conductors, so the installation and repair equipment for both cable types is effectively the same.
{googleAdsense}
Network Rail also believes that since aluminium cables are considered to be less attractive to thieves than copper conductors, this will lead to a reduction in the disruption caused by cable theft.
As Network Rail and its suppliers and contractors are facing a cost reduction challenge, this move, they think, is relatively simple and can deliver huge cost savings. Network Rail has scheduled a copper-elimination learning day for the industry on 27 July 2017 to explain how with the help of technology and novel processes, they can avoid unknown risks involved in securing the benefits of delivering a cheaper and secure copper-free distribution system.
Responses
