System Strength Impact Assessment Guidelines amendment consultation

Market National Electricity Market
StageDraft Report
ConvenorAEMO NEM
Accepting submissions?Yes
Submissions close21/05/2024


  • Draft report and draft SSIAG published
    22 April 2024
  • Submissions due on draft report and draft SSIAG
    21 May 2024
  • Final report and final SSIAG
    30 June 2024

Key contact

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AEMO is consulting on amendments to the System Strength Impact Assessment Guidelines (SSIAG) following the Australian Energy Market Commission’s (AEMC) final determination on Calculation of System Strength Quantity rule change.


In April 2023, AEMO identified that applying the System Strength Quantity (SSQ) formula in the NER, without adjustment, could significantly overstate the quantity of system strength required to support each connection. AEMO published guidance on Calculating system strength quantities in the NEM in May 2023 outlining the issue and proposing an adjusted formula that incorporates a stability coefficient, the same value applied in the reduction in available fault level (AFL) calculation.

In September 2023, AEMO submitted a rule change proposal to the AEMC proposing amendments to relevant clauses of the NER. The AEMC completed industry consultation and made its final determination and final rule on 29 February 2024.

The final rule requires AEMO to update the SSIAG in consultation with stakeholders by 30 June 2024, with an effective date of 1 July 2024.

Key changes

The proposed amendments to the SSIAG are set out in detail in the draft report, and summarised below:

  • Incorporates a methodology to calculate SSQ, including guidance on the inputs and assumptions
  • A number of minor and administrative changes, including:
    • The introduction of terminology and concepts that are consequential on amendments to the NER made by the Integrating Energy Storage Systems (IESS) Rule, for which full implementation will occur on 3 June 2024;
    • Clarification of the way in which the existing concept of the stability coefficient is defined and described in the Guideline;
    • Clarification of the number of decimals to be used in calculating the Withstand SCR; and
    • Other minor corrections and clarifications to the text of the Guideline.


AEMO invites written submissions from interested persons on the draft report and the draft proposal to by 5:00 pm (AEST) on 21 May 2024.

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