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Reducing bushfire risks

Powercor’s journey introducing a remotely controlled Automatic Circuit Recloser (ACR)

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The challenge The Black Saturday bushfires in February 2009 are known as the worst fire catastrophe in Australia with several fires started by electricity distribution networks. To avoid such disasters, the Victorian Bushfires Royal Commission (VBRC) was established to investigate the causes and responses to the bushfires. The final report of the commission delivered 67 recommendations, with eight of them aiming directly at electricity distribution businesses.

Minimizing bushfire risks from electricity networks

As a result, the distribution company Powercor was required to replace 1,062 legacy hydraulic Automatic Circuit Reclosers (ACRs) with new devices capable of remote control. The ACR’s were spread over thousands of kilometers of single wire earth return (SWER) network in rural Victoria, so the installation time was a serious concern in the project cost. The regulator mandated the program be completed within a five-year period ending on 1st January, 2021. The Bushfire Mitigation Civil Penalties Scheme Amendments meant Powercor faced significant financial penalties if the project was not completed on time: An initial $50,000 per site late fee, and a $150 per day per site thereafter late fee provided motivation for an aggressive deployment program.

Powercor not only had to find an innovative solution providing the required functionality, but also one that was cost-effective, and quick to install and commission to meet the target date.

The customer Powercor owns and operates a network that is in one of the world’s harshest environments – and one with the highest risk of bushfires.

Despite some challenges, program costs are still 20-40% cheaper than using alternative technology and the project is currently on track to be completed one year earlier than originally planned.

Dene Ward, Network Safety and Bushfire Mitigation Manager at Powercor Australia & CitiPower

Keeping Victoria up and running

With about 90,000 kilometers of distribution lines, of which 87 percent are overhead lines, Powercor delivers electricity to about 780,000 homes and businesses in Victoria. The network encompasses major population bases such as the western suburbs of Melbourne, Geelong, Ballarat and Bendigo, as well as a large geographical rural area.

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The solution "When it came to fulfill the VBRCs recommendations, Powercor was looking for a partner that had a solution that fulfilled the mandated performance requirements and allowed for time and cost-efficient installation. Additional technical features to mitigate bushfire risks were also attractive. The fundamental requirement for bushfire mitigation on SWER networks is to be able to turn off the automatic closing function on extreme risk fire days via remote access from the control center. Fusesaver™ with Remote Control Unit (RCU) fulfilled this core function with a purchase price significantly lower than traditional solutions."

The world’s fastest circuit breaker reduces fire start risks

On extreme risk bushfire days, the goal is to eliminate any possible danger caused by electric faults. Arc duration plays a significant role. Minimizing the arc energy reduces the fire start risk. Traditional circuit breakers have clearing times around 50 ms, which is long enough to still leave a significant probability that an arc may cause fire ignition. When the clearing time is less than 20 ms, the probability of arcs igniting a fire approaches zero. Fusesaver™ is the only circuit breaker with an unsurpassed clearing time as low as 10 ms (half-cycle) providing maximum protection on high risk fire days. With the reclose functionality inhibited via remote control, the protection can also be changed to an ultrafast mode with half cycle clearing time – a setting that reduces the probability of an arc causing an ignition effectively to zero.

Close collaboration as key to success

Energy Safe Victoria (ESV), the independent technical regulator, was given the task to direct, oversee, review and report the measures taken by Powercor. So right from the beginning, Powercor placed high value on collaborating closely with Siemens to achieve ESV approval of the Fusesaver™ over a four month process. In this time, Siemens provided comprehensive support and technical details to Powercor and ESV to prove that the Fusesaver™ met all the new regulations. The additional fire risk mitigation benefits due to Fusesaver’s™ ultrafast operating time and the faster installation of the product were positively acknowledged. In January 2017, Powercor obtained acceptance for using the Fusesaver™ as a “new generation” SWER ACR, so large-scale deployment could begin.

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The result Fusesaver™ helps Powercor to fulfill the requirements of the VBRC and ensure reliable power supply for 780,000 homes and businesses in Victoria – and keeps bushfire risk as low as possible.