Victoria sizzles, power fizzles in 24-hour power outage

Searing heat last Monday resulted in an almost 24-hour power outage across parts of northern Victoria.

In the Mitchell Shire, many residents were left without electricity for over 17 hours, with the power switching off just before 7pm on Monday, December 16, as temperatures soared to 38 degrees.

While power was restored to the majority of locals by 11am the following morning, residents in parts of Kilmore East had to wait until 1.30pm to have access to power again, with those in Broadford having to wait until the evening to be reconnected after experiencing a second outage at 11.30am.

Though many believed the outages to be a result of load shedding—a deliberate outage to reduce stress on the network—or a blackout as the grid struggled to handle the number of Victorians relying heavily on cooling systems, the outages were largely the result of bushfire mitigation technology.

First installed in 2017 and now operating across 45 high-risk bushfire locations, Rapid Earth Fault Current Limiters (REFCLs) prevent energy flow to powerlines when a fault occurs—such as when a powerline comes into contact with the ground or vegetation—reducing the risk of an electrical spark igniting a fire.

The installation of the technology follows a State Government mandate issued in May 2016, after the 2009 Victorian Bushfire Royal Commission found that six of the 11 most catastrophic Black Saturday bushfires were ignited by high voltage powerlines.

Together, these six fires resulted in the deaths of 159 people, and 328 injuries. The fires also destroyed 1832 homes and other property.

On Total Fire Ban and Catastrophic fire danger rating days, REFCLs are required to operate at a greater sensitivity and may shut down sections of the network when a fault, even a minor one, occurs. When the REFCL technology is triggered, the entire feeder line is disconnected from power, rather than just a single line or a few sections.

Before electricity can be restored, the lines must be physically patrolled to locate, identify—and if required—clear the cause of the fault, which is often a time-consuming process.

However, it appears that inspectors were not sent out to assess the lines until Tuesday morning, after an AusNet update at 7.30am stated that a helicopter had been ‘arranged’ to patrol the lines responsible for outages in Kilmore East and Broadford.

AusNet did not respond to the Review’s enquiries as to why it took inspectors almost 12 hours to patrol the lines, nor state why the technology had not been improved to quickly locate and identify the trigger of the REFCLs.