Choosing the Right Conductor Material for Australian Power Lines

Selecting the right conductor material for Australian power lines isn’t a one-size-fits-all approach. Our diverse landscape throws a variety of challenges at these conductors, from the scorching heat of the outback to the high winds of coastal regions. Furthermore, factors like the length of the transmission line and the amount of electricity it needs to carry all play a role.

Here in Australia, we need to consider:

• Current Carrying Capacity: The conductor needs to handle the planned electricity flow without excessive energy loss.
• Line Length: Longer lines experience greater electrical losses, influencing material selection.
• Climate: Harsh weather conditions like high winds, ice, and snow play a role.
• Corrosion: Proximity to salty air, particularly near our coastlines, or industrial pollution impacts material choice.
• Physical Requirements: Span length between towers and maximum tower height influence conductor selection.

For the past two decades, AAAC 1120 has been the preferred material for large Australian transmission lines. This is because it offers the best balance between:

• Strength: AAAC 1120 is stronger than pure aluminium (AAC), crucial for long spans and harsh weather.
• Electrical Conductivity: It efficiently carries electricity, minimizing power losses.
• Cost: Compared to some options, AAAC 1120 provides a cost-effective solution.

• Aluminium Conductor Steel Reinforced (ACSR): Offers even greater strength than AAAC, making it suitable for extreme weather conditions like cyclones or heavy snow loads.
• All Aluminium Conductor Steel Reinforced (AACSR): Similar to ACSR, but with an aluminium-clad steel core for enhanced corrosion resistance in coastal areas.
• All Steel Conductors: Used for earth wires (grounding wires) to maintain minimal sag compared to phase conductors.

For steel-reinforced conductors (ACSR, AACSR), the core material decision depends on the level of corrosion protection needed.

• Galvanised Steel: A cost-effective option for drier inland areas, often protected with special grease.
• Aluminium Clad Steel: Provides superior corrosion resistance in coastal environments or areas with high pollution. It also offers slightly higher current carrying capacity due to better conductivity.

Earthwires typically utilize ACSR or all-steel construction for minimal sag compared to phase conductors. Their size depends on fault current requirements and lightning activity in the area. The choice between galvanised and aluminium-clad steel for earthwires follows similar principles as phase conductors.

Beyond cost and performance, some projects might consider the environmental impact of conductor materials. Aluminium production generally requires less energy compared to steel. While the overall impact is complex, this can be a factor in selecting a conductor material.

The future of power transmission might involve new considerations for conductor materials. The integration of large-scale renewable energy sources or advancements in conductor technology, such as high-temperature superconductors, could influence future material selection.

It’s worth noting that the chosen conductor material can also have an aesthetic impact on the visual landscape. While functionality remains the priority, conductor diameter and material properties can influence how noticeable power lines are in certain environments.

Many new power lines incorporate OPGW, which integrates optical fibers within the earthwire. This allows for communication, control functions, and even potential revenue generation by leasing fiber optic capacity. Due to the importance of long service life and high replacement costs, OPGW nearly always utilizes aluminium-clad steel for its construction.

Understanding these factors and material options ensures that the most suitable conductors are chosen for reliable and efficient power transmission across Australia’s diverse landscapes.