The Calvale to Calliope River Transmission Line Reinforcement Project will be the first Powerlink project to use High Temperature Conductor (HTC) technology. These specialised conductors can carry significantly more electrical current than traditional conductors of the same size.

Using HTC technology helps us make smart use of our new infrastructure. It maximises capacity to deliver an efficient, reliable and best‑value solution.

HTCs at a glance:

• They can carry far more current, often up to twice as much as a standard conductor of the same size.

• They allow up to an 85% increase in emergency rating, meaning the line can safely carry much more current in high‑demand or emergency scenarios.

How do they work?

All conductors heat up under electrical load. When conventional conductors exceed around 80°C, they experience a change in their internal structure. This weakens them over time and reduces their expected service life. In comparison, HTC conductors use specialised materials so they can operate reliably at high temperatures over the long term.

What are they made of?

Powerlink is using a specific type of HTC technology called ‘thermal resistant’ technology. Like traditional conductors, thermal resistant conductors also have a steel core. What sets them apart is the heat-resistant aluminium alloy that surrounds the core, enabling them to operate at high temperatures.

Why are the transmission towers taller?

As electrical current flows through a conductor, it heats up and expands. As the temperature increases, the conductor becomes longer and sags more between towers. This is an important consideration during transmission line design, to ensure safe clearances are maintained in all operating conditions.

Because thermal resistant conductors are designed to operate at higher temperatures, the towers need to be taller to safely accommodate this additional sag. This is why the new towers along the Calvale to Calliope River line will be taller than the existing towers beside them.