It's a case of 'damned if you do, damned if you don't' for electricity supply companies this coming fire season, as regional communities, including Ballarat, face increased power outages this summer due to new safety devices.
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A significant element of the 2009 Victorian Bushfires Royal Commission was the finding that electrical assets could dramatically add to the percentage of fires ignited on days of extreme fire danger.
"Electricity-caused fires are most likely to occur when the risk of a fire getting out of control and having deadly consequences is greatest," the final report found.
The Commission directed the state regulator Energy Safe Victoria be given more powers and act less passively, and infrastructure be compulsorily updated.
As a result, Powercor is just one company installing Rapid Earth Fault Current Limiter (REFCL) devices.
The REFCLs are being installed in some of the state's highest bushfire risk areas, as directed by the Victorian Government in response to recommendations from the Victorian Bushfires Royal Commission.
The devices at Ballarat have been installed ahead of the deadline for this group of REFCL devices, known as Tranche 2, which is April next year.
An REFCL device, in layperson's terms, essentially acts as a kind of giant trip switch, cutting the current from a faulty line to the earth and thus preventing arcing fires being caused.
According to a 2011 RMIT study, the REFCL usually limits voltage within 10 milliseconds, cutting the current to zero.
The devices can be calibrated for sensitivity. Powercor says on days of total fire ban the REFCLs are set to their most sensitive setting, meaning outages may occur more frequently and last longer.
The Commission considers that now is the time to start replacing the ageing electricity infrastructure and to make major changes to its operation and management. The seriousness of the risk and the need to protect human life are imperatives Victorians cannot ignore. The number of fire starts involving electricity assets remains unacceptably high-at more than 200 a year. Although it is not possible to eliminate the risk posed by electricity assets, the State and the distribution businesses should take the opportunity to invest in improved infrastructure and substantially remove one of the primary causes of catastrophic fires in Victoria during the past 40 years.
- Royal Commission into the Victorian Bushfires
"Our crews patrol the lines after each fault before we can safely turn the power back on," Powercor said in a release regarding the installation on the REFCLs in Ballarat.
"When a REFCL operates, it's responding to a fault that has the potential to cause a fire and is keeping the network safer for our customers."
Thousands of residents to the south of Ballarat were left without power for about an hour on Friday in the latest of a series of outages.
Powercor says it's examining ways to reduce these outage times
A Powercor spokesperson said outages this week caused by final installations, and by device trips overall, are being assessed.
"We are aware of the inconvenience this has on our customers and are exploring ways we can get power restored as quickly as possible without compromising safety," the spokesperson said..
Final testing of the technology is taking place this week, ahead of Ballarat's Fire Danger Period declaration on December 14.
"The Rapid Earth Fault Current Limiter (REFCL) devices are located at the Ballarat North and Ballarat South Zone Substations, with both devices now protecting high voltage powerlines across the region," Powercor REFCL technical director Andrew Bailey said
"The Ballarat devices now protect 2,861km of high voltage powerlines which supply almost 70,000 customers. This will be the first summer that all 22kV high voltage powerlines in Ballarat will be protected by REFCL, and it represents an enormous safety upgrade for the region. This is the single largest upgrade for the electricity network in decades."
Powercor crews have worked through COVID lockdowns to complete upgrades at hundreds of sites across the Ballarat network area to prepare the network to support the new devices. This included several planned outages to allow crews to safely conduct upgrades.
"We'd like to thank our customers in Ballarat for their patience as we've done this work to make this important safety upgrade," Mr Bailey said.
During the 2019-2020 summer, Powercor had REFCLs at 10 Zone Substations in service and operating at heightened sensitivity settings on total fire ban days.
On 21 November 2019, which was Victoria's first code-red declared Total Fire Ban day (in Mallee and Northern Country) since Black Saturday, REFCLs detected and activated for six permanent faults and eight short-term faults.
Between October and the end of January 2020, there were 17 total fire ban days in western Victoria. On these days, REFCLs activated 13 times for permanent faults, 22 short term and 75 temporary faults.
Monash University chair of the Grid Innovation Hub Dr Tony Marxsen has studied the electrical causes of fire extensively.
In a personal paper he writes REFCL installed in Australia are more consistent at stopping fires than overseas experince because they are the latest technology and are used more effectively.
"Detailed estimation and modelling show Victoria's REFCLs will cut powerline fire-risk to a much greater degree than simple theory or experience elsewhere might predict... by 70 to 75 per cent on average. Early experience supports this estimate," Mr Marxsen writes.
Critics of the REFCL devices say they force current load from shut-down wires to other wires and can double the load, forcing secondary faults in other areas and potentially causing additional fires.
Australia's leading earthing engineer Dr Bill Carman says REFCLs "at the most optimistic estimate will only reduce some 60 per cent of the likelihood of an earthfault created fire, and there is still a relatively high likelihood that a high societal cost fire might occur."
Australia's REFCL devices are manufactured by Swedish Neutral AB.
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