The Reliability Panel has published a draft determination to declare the risk to South Australia’s power system posed by destructive wind conditions as a ‘protected event’. Under the National Electricity Rules, the Panel can declare a ‘protected event’, in response to a request from AEMO, if it finds there are net economic benefits from AEMO taking certain pre-emptive actions to manage a particular risk. 

In June 2018 AEMO released its first Power System Frequency Risk Review. This review identified a heightened risk of faults on transmission lines in South Australia during very high winds - above 140 km per hour - which could lead to the loss of the Heywood interconnector between South Australia and Victoria, and possibly a widespread blackout. 

AEMO is currently managing this risk by constraining the amount of power being imported into South Australia on the interconnector when destructive winds are forecast. However, AEMO believes there are more transparent and cost-effective ways to manage this risk, including by upgrading the technology used in existing emergency control schemes. These schemes employ various actions to respond to such events, including the rapid injection of power from batteries in South Australia.

The Panel has assessed AEMO’s request and determined there are net economic benefits from AEMO taking additional pre-emptive action to manage the relevant risk to the power system. The Panel also agrees that AEMO’s recommended option for managing the protected event is the most technically robust and cost-efficient of the options identified. AEMO proposes to manage the risk by: 

  • upgrading the existing system integrity protection scheme (SIPS). This includes upgrading the monitoring and communication equipment used to detect when the interconnector is at risk and signal the need for a rapid injection of power from South Australia’s utility-scale batteries to stabilise the system; and 
  • limiting the total import capacity over the Heywood interconnector to 250 MW at times when destructive wind conditions have been forecast in South Australia.

The Panel’s determination has been informed by analysis provided by AEMO, stakeholder feedback on the consultation paper, and external technical advice.

Submissions on the draft determination are due by 9 May 2019

This work is part of the AEMC’s system security and reliability action plan.

Media: Prudence Anderson, Communication Director, 0404 821 935 or (02) 8296 7817;


In March 2017 the AEMC released a new management framework for emergency frequency control schemes. These are ‘last line of defence’ mechanisms to help prevent system-wide blackouts.

As part of this framework, AEMO is required to regularly and transparently assess risks to power system operation caused by events that are unlikely but would have high impacts if they were to happen. 

If AEMO believes that there are more transparent and cost-effective ways of managing any of the risks it identifies in its Power System Frequency Risk Review, it can request that the Reliability Panel declare a risk as a ‘protected event.’ 

The Reliability Panel will then consider the net economic benefits of managing the event as a protected event. If the Panel declares a protected event, AEMO can take additional steps to proactively manage the risk.