Rule Change: Open

Overview

On 26 May 2020 the AEMC received a rule change request from the COAG Energy Council (since replaced by the Energy National Cabinet Reform Committee (ENCRC) and the Energy Ministers’ Meeting (EMM)) to amend the National Electricity Rules to introduce a framework to manage indistinct events.
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On 26 May 2020 the AEMC received a rule change request from the COAG Energy Council (since replaced by the Energy National Cabinet Reform Committee (ENCRC) and the Energy Ministers’ Meeting (EMM)) to amend the National Electricity Rules to introduce a framework to manage indistinct events.

Indistinct events are events that can impact multiple generators or transmission lines in an unpredictable and uncertain manner. Indistinct events may include major storms, widespread fires and cyber attacks, which may trigger unpredictable responses in an increasingly complex power system. As power system technology evolves and as storms and bushfires become more intense and frequent, these indistinct events are becoming an increasing threat to maintaining a secure supply of electricity to customers.

The rule change request from the COAG Energy Council proposes to amend the National Electricity Rules (NER) to implement a framework to manage indistinct events.

This follows a recommendation made by the AEMC in its Mechanisms to enhance resilience in the power system—review of the south Australian black system event (the BSE review). In the BSE review, the AEMC found that the existing system security framework may be ill-suited to managing indistinct events and recommended introducing a framework for protected operation, as a new operational tool for AEMO to enhance the resilience of the power system to indistinct events.

Draft Determination

The Commission’s draft determination is to make a draft rule that is a more preferable rule. The more preferable rule is nonetheless broadly consistent with the solution proposed by the COAG Energy Council in its rule change request. 

The draft rule amends the definition of contingency event to address ambiguity by:

  • clarifying that it is the risk of an event on the power system not the conditions affecting the power system that AEMO should manage
  • broadening the definition to include ‘plant’ rather than just generating units and/or transmission elements
  • including sudden and unplanned changes to loading alongside failure or removal from service

This amendment would allow AEMO to manage indistinct events within the existing, established frameworks. The Commission considers this should be more efficient than introducing a new parallel framework just for indistinct events. 

Indistinct events would be managed under AEMO’s existing framework. This includes the requirement to consult on amendments to the reclassification criteria for when AEMO considers a non-credible contingency event has become reasonably possible and the actions AEMO will take to manage reclassified events. 

AEMO would be allowed to manage contingency events reclassified as credible due to abnormal conditions outside of the reclassification criteria to support system security. But for transparency of system operation, these events would be considered reviewable operating incidents and AEMO would be required to assess (through the general power system risk review) whether changes are required to the reclassification criteria. 

The Commission proposes to review these arrangements within 5 years of the commencement of the final rule. 

Submissions to the draft determination close 6 January 2022.

Initiation

On 17 December 2020, the Commission published a consultation paper to commence the rule making process and consultation for this rule change request, Enhancing operational resilience in relation to indistinct events. 

The consultation paper considered the proposed rule from the COAG Energy Council to:

  • introduce the new definition of an ‘indistinct event’ 
  • clarify that standing risks from indistinct events can be managed as a type of protected event 
  • enhance the protected event approval process to manage standing indistinct events 
  • implement a new operational tool, protected operation, allowing AEMO to more effectively manage condition-dependent indistinct events
  • set out two types of protected operation:
  • pre-defined protected operation, and
  • ad-hoc protected operation 
  • specify governance arrangements for protected operation. 

The proposed rule change aimed to enhance the security and resilience of the power system, and make operating the power system more efficient and effective, by allowing AEMO more flexibility to prepare for and manage indistinct events.

Submissions to the consultation paper closed 11 February 2021. The Commission received 7 submissions as part of this stage of consultation.

Extension of time

On 22 April 2021, the AEMC extended the time to make the Enhancing operational resilience in relation to indistinct events draft rule until 28 October 2021. The extended timeframe was needed due to the complexity of issues raised in the rule change request and feedback received from stakeholders in submissions to the consultation paper requesting extra consultation.

Other relevant BSE review rule change processes

This was the third rule change request that the COAG Energy Council submitted following the BSE review. Information on the other BSE review rule changes can be found at the links below:

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Documentation