Cable system to reduce bushfire risk

Electricity and gas company SPAusNet is trialing an insulated cable system in an effort to reduce the risk of bushfires and vegetation causing power interruptions.

The Hendrix Spacer Cable was recently commissioned by Western Australian electricity distributor Western Power and has a unique system using covered conductors in close triangular configuration protected by an overhead wire.

The technology has the mechanical strength to weather severe storms and the electrical strength to prevent temporary faults due to phase-to-phase or phase-to-ground contact from tree branches or animals.

The messenger wire, spacers and brackets work as a system to be self-supporting and to provide protection from branches and trees that have the potential to bring down overhead circuits during storm events.

SPAusNet network safety manager Phillip Bryant said the trial, which is a first for Victoria, is demonstrating covered cable is a genuine option to complement insulated high-voltage aerial bundled cable, to reduce bushfire risk and improve supply reliability.

“We were faced with the task of co-ordinating the procuring of material, training resources, arranging outages and liaison with customers to ensure the project was delivered to SPAusNet’s safety standards,” he said.

“We chose a 1.4km stretch of road in Coldstream, east of Melbourne, to conduct the trial, which required the replacement of an existing section of 22kV bare wire network.”

SPAusNet is also working to reduce bushfire risk from electricity infrastructure by implementing recommendations from the Victorian Bushfire Royal Commission (VBRC) and the state government’s $750 million Powerline Bushfire Safety Program (PBSP).

The 10-year PBSP will deliver on recommendations of the VBRC and aims to reduce the risk of bushfires caused by electrical assets without causing significant impact on electricity supply reliability.

“The findings of the spacer cable trial will assist us in evaluating the options to underground or install insulated and covered cables as part of the State Government’s Powerline Bushfire Safety Program,” Mr Bryant said.

“We believe for a 22kV cable, the spacer cable would be between half and a third of the cost of undergrounding and possibly about 75 per cent of the cost of aerial bundled cable.”

Energy Safe Victoria director of energy safety Paul Fearon commended SPAusNet for undertaking the trial and being willing to share the learnings with industry and the safety regulator.

“SPAusNet’s trial with the spacer cable is a great example of an alternative technology that VBRC recommended must be pursued to reduce the risk of wires causing fires in areas of highest bushfire risk,” Mr Fearon said.

Each year, SPAusNet administers bushfire preparedness communications and stakeholder engagement campaigns promoting bushfire safety throughout its regional network.