IEEE Power & Energy Magazine - January/February 2022 - 57

separated and treated as regulated monopolies, and generation
and retail became fully competitive sectors. Consumer
competition laws restrict the ownership of generation assets
by T&D businesses.
There are five distribution businesses in Victoria. Two of
the largest, PowerCor and AusNet, own the networks faced
with the majority of bushfire risk in the state. The remaining
networks generally provide service in Melbourne metropolitan
areas, where there is no significant risk. AusNet also
owns and operates the transmission network across the
state, which has direct interconnections with South Australia,
New South Wales, and Tasmania.
Victoria's Bushfire-Mitigation Plan Evolution
Electrification of rural Victoria was completed by 1972, and
since then, three major bushfire events in 1977, 1983 (the
Ash Wednesday bushfires), and 2009 ( " Black Saturday " )
have driven the evolution of bushfire-mitigation strategies in
Victoria. The measures used to reduce ignition of bushfires
have included
✔ the introduction of computer-based systems increased
transparency across the network of workloads, asset
maintenance, and performance issues in the late
1980s and early 1990s. A code of practice was adopted
for vegetation management (1983) to establish
prescribed clearance spaces to powerlines and avoid
contact with trees.
✔ a statewide program began to retrofit low-voltage
spreaders to all spans to avoid the clashing of bare
wires at low voltage.
✔ the development and installation of fire chokes on
fuze units to prevent high-voltage expulsion drop-out
fuzes expelling hot particles.
✔ the development of an asset inspection manual and inspector
training to achieve consistency in inspection
standards.
The Ash Wednesday bushfires of 1983 in southeast Australia,
unfortunately, repeated 26 years later in 2009 with
similarly extreme fire conditions. The Victorian Bushfire
Royal Commission, established after the fires, found that
many of the most significant fires were caused by distribution
network assets.
The additional interventions since 2009 include fuelreduction
targets for annual burn-offs in state and national
parks to reduce potential fire intensity, and a government
incentive policy to encourage distribution businesses to
undertake bushfire mitigation. A financial incentive mechanism,
similar to the established network reliability one, was
introduced to focus network operators' attention on bushfire
risks. The government adjusts the financial target each year,
considering anticipated benefits from mandated bushfiremitigation
programs, which impact the distribution businesses'
revenue according to their performance.
In 2017, the responsible minister ordered an industry
review that focused on opportunities for enhancing network
january/february 2022
safety, including identifying the characteristics of leading
safety regulation frameworks (prescriptive versus risk based),
and those of an effective safety regulator. The review investigated
safety frameworks utilized nationally and internationally
and confirmed the benefits of a risk-based framework.
The review also concluded that increased regulatory powers,
supported by communities and the government, are needed
to address perceptions or failures of utilities to take appropriate
actions to mitigate network safety risks and hazards.
Following the safety framework review in 2017, comprehensive
bushfire-mitigation strategies in Victoria were
updated for both T&D networks. In general, the bushfiremitigation
plan can be separated into preventive strategies
and emergency response during bushfire events.
Bushfire-Mitigation Strategies
for Transmission Networks
There is no history of bushfire ignition from Victoria's transmission
network. However, the impact of bushfires on the
transmission system has typically been fast-moving in heavily
forested areas adjacent to the transmission easements. Several
mitigation strategies are now operational for transmission networks
in Victoria and other states of Australia, which consist
of preparation and planning for bushfire events (preventive
strategies) and prompt response in case they occur.
Preventive Strategies
The key preventive strategies for bushfire events relate to
adequate asset management and vegetation management
plans in advance of fire season. A total fire ban is in place on
days when fires are likely to spread quickly and be difficult
to contain. On these days, T&D network businesses require
special permits to use any fire (e.g., welding torches), and
any work scheduled in fire hazard areas must be suspended
unless special approval is granted.
Asset Management Strategy
General asset inspection and maintenance programs are in
place that aim to, among others, prevent the occurrence of
bushfires. The specific actions of particular note for bushfires
include
✔ Annual
line and easement
inspections: Qualified
technicians will inspect all lines, assets, and easements
following process and evaluation requirements
outlined in " Lines Practices and Procedures. " The annual
patrols of entire networks identify line defects
such as broken insulators, conductor strands, bird
nests, and so forth, aside from aspects such as proximity
to vegetation.
✔ Tower climbing inspections: These inspections are
performed on a schedule (three, six, or nine years)
proportional to the probability of an asset failing in
a particular area (including due to bushfires). Visual-based
guidelines are applied with scores of 1-5 to
monitor and model asset deterioration.
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IEEE Power & Energy Magazine - January/February 2022

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