What are Aluminium Conductors used for?
Aluminium Conductors are predominantly used in Overhead Line applications and for primary and secondary power distribution.
The higher strength ACSR conductors are used for river crossings, overhead earth wires, and installations involving extra long spans. The advantage of ACSR is that it has high tensile strength and is lightweight, which means over longer spans it needs less supports. ACSR is available with varying percentages of steel core to achieve different strengths. One of the advantages of this conductor in particular is that the desired strength can be achieved without a loss of ampacity.
AAC is used mainly in urban areas where the spacing is short and the supports are closer together. The advantage of AAC conductors is that they have a high degree of corrosion resistance; for this reason they are used extensively in coastal areas. AAC Conductors were developed as a consequence of the galvanic corrosion that ACSR conductors are susceptible to.
AAAC is used as bare overhead conductor for power transmission and distribution lines on aerial circuits that require larger mechanical resistance than AAC. AAAC also has better sag characteristics and a better strength to weight ratio than AAC. AAAC Cables have lower weight per unit length and slightly lower resistance per unit length than ACSR.
What is the difference between ACSR, AAC and AAAC Conductors?
The biggest difference between AAC, AAAC, and ACSR conductors are the materials they are constructed from. AAC is manufactured from electrolytically refined aluminium with a 99.7% minimum purity, AAAC is made from an Aluminium alloy, and ACSR contains a combination of Aluminium reinforced with Steel.
The second factor that differentiates the three cables is their resistance to corrosion, which is important for the longevity of the cable. ACSR has a poorer resistance to corrosion, as it contains steel, which is prone to rust. AAAC and AAC have a better corrosion resistance, due to the fact that they are largely or completely aluminium.
In an ACSR the galvanised steel core carries the mechanical load and the high purity aluminium carries the current. These utilise the lower thermal expansion coefficient of steel compared to aluminium, which the aluminium based conductors AAC and AAAC are unable to do.