How networks determine cutting supply in severe weather

SA Power Networks

SA Power Networks has detailed the process involved in switching off electricity supply during times when fire danger warnings reach catastrophic levels.

Earlier this month, SA Power Networks cut power to Port Lincoln and surrounding areas as a preventative measure to reduce the risk of a fire start during the escalating bushfire conditions, a decision they say is not taken lightly.

Emergency Management manager Frank Crisci explained what goes into reaching a decision like this.  

“We had a situation where the fire conditions were worsening. There were very strong and strengthening winds and the fire danger conditions were escalating,” Mr Crisci said.

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“Often in conditions like this where we have had a hot, dry summer and windy conditions, tree branches fall on powerlines. When the powerline comes into contact with the ground, it can start a fire.”

SA Power Networks says it has only disconnected power in these circumstances 10 times since 1985 and it is more likely that customers would lose power in bushfire conditions either because of damage from falling vegetation or due to damage from an actual fire.

That just reinforces the importance for people in bushfire areas to follow CFS’ advice and prepare a Bushfire Plan, which includes being prepared for the possibility of losing power.

“In normal conditions, the CFS is able to respond and contain a fire, but in fire danger conditions like those at Port Lincoln on Friday, if a fire had started, CFS would not have been able to control it,” Mr Crisci said.

On Friday, April 5, we had reports of trees down around the state, and fire starts. At Port Lincoln the wind was so strong that it was moving our powerlines around quite violently. After then consulting with the CFS, we made the assessment that the fire start risk in the area was too high, so we switched off power to Port Lincoln and surrounds.

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Frank said after the Ash Wednesday fires in 1983, legislation was put in place that gives SA Power Networks as the state’s electricity distributor the authority to switch off power when we form the opinion that it’s too dangerous for the power to stay on.

“Our focus is protecting lives and property.”

In reaching the decision to switch off, SA Power Networks says it:

  • uses Bureau of Meteorology weather station observations
  • consults with the Country Fire Service on localised fire danger conditions
  • monitors media for information on impacts of local weather conditions e.g. windborne debris