DISASTER MANAGEMENT
BLACK SYSTEM OR BLACK SWAN:
LEARNINGS FROM SOUTH AUSTRALIA’S INFAMOUS 2016 BLACKOUT by Imogen Hartmann, Associate Editor, Energy magazine
Reliability stands as one of the three pillars of the energy industry’s most coveted objectives, along with affordability and sustainability. With the phrase “keeping the lights on” so often used by industry leaders and policy makers, it’s no wonder that when the lights truly went out in South Australia in 2016 it caused a nation-wide stir. As the state’s 1.7 million residents were plunged into darkness following a massive storm, one question was on everyone’s minds: what went wrong? In the first part of this series examining the South Australian blackout, we use the benefit of five years worth of hindsight to examine the events that occurred in the leadup to and during the crisis.
D
uring the period 28 to 30 September 2016, a storm dubbed as a “once-in-50year” weather event tore through South Australia. The intense low pressure system saw winds of up to 140km/h hit Adelaide, eliciting an unprecedented warning from police for workers to head home early and stay home to preemptively alleviate pressure for emergency services. Trees were brought down in some areas, causing major damage to infrastructure and the heavy rain resulted in widespread flooding, from the Patawalonga River in Adelaide, through to the Barossa and Clare valleys. Along with destructive winds, the super cell storms brought with them twin tornadoes that decimated northern parts of the state. 22 transmission towers that carried electricity generated near Port Augusta to the rest of the state were ripped out of the ground, and three major transmission lines were brought down. Energy infrastructure also copped a severe amount of damage from 80,000
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lightning strikes that hit the state over a short period. As South Australia was plunged into darkness by a state-wide blackout, then Premier, Jay Weatherill, described what had happened as “catastrophic”. The event has since been described as a black swan – an unpredictable, rare event that falls outside of what is normally expected of a situation, often with severe consequences. The defining characteristic of a black swan event is a surrounding narrative that it was obvious or avoidable in hindsight.
Protection systems triggered Two tornadoes with wind speeds in the range of 190-260km/h resulted in a single circuit 275kV transmission line and a double circuit 275kV transmission line, some 170km apart, simultaneously sustaining serious damage. The transmission lines tripped as a result, with a sequence of faults in quick succession causing six voltage dips on the South Australian grid over a two-minute period at around 4.16pm on Wednesday 28 September.
Concurrent with a growing number of faults on the transmission network, nine wind farms located in the state’s mid-north showed a sustained reduction in power – a protection feature activation. Protection settings in eight of these wind farms enabled them the capability to withstand a pre-set number of voltage dips within a two-minute period. As this protection feature was activated, the wind farms sustained a hefty generation reduction – 456MW – over a period of less than seven seconds. Just as the wind farms have inbuilt protection systems, so too do the poles and wires. Generators create power, but they also affect the voltage and the frequency of the electricity network – something that requires careful maintenance in order to protect everything that’s connected to it. When the 22 high-voltage power pylons went down, it triggered a series of automatic safety switches designed to protect the greater South Australian power network – and the rest of the National Electricity Market (NEM).
www.energymagazine.com.au
