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144186CONSTRAINTS02/06/2026 02:03:25 PM
Increase in Heywood from SA to Vic test limit from 550 to 600 MW
AEMO ELECTRICITY MARKET NOTICE
AEMO will increase the Heywood test limit from SA to Vic (from the current 550 MW) to 600 MW today to conduct internetwork testing on Heywood.
The following constraint sets will be revoked once the testing criteria met:
I-SV_HEY_550_TEST
The following constraint sets will be invoked:
I-SV_HEY_600_TEST
AEMO will revert the Heywood test limit back to 550 MW once the test has completed while the test result being analysed.
Please also refer to the published formal PEC Stage 1 and HIC capacity release testing information at the following link: https://aemo.com.au/-/media/files/stakeholder_consultation/consultations/nem-consultations/2023/project-energyconnect-stage-1-and-hic-capacity-release/pec-stage-1-and-hic---final-test-program.pdf?la=en.
Terry Liu
AEMO Operations
AEMO will increase the Heywood test limit from SA to Vic (from the current 550 MW) to 600 MW today to conduct internetwork testing on Heywood.
The following constraint sets will be revoked once the testing criteria met:
I-SV_HEY_550_TEST
The following constraint sets will be invoked:
I-SV_HEY_600_TEST
AEMO will revert the Heywood test limit back to 550 MW once the test has completed while the test result being analysed.
Please also refer to the published formal PEC Stage 1 and HIC capacity release testing information at the following link: https://aemo.com.au/-/media/files/stakeholder_consultation/consultations/nem-consultations/2023/project-energyconnect-stage-1-and-hic-capacity-release/pec-stage-1-and-hic---final-test-program.pdf?la=en.
Terry Liu
AEMO Operations
144142CONSTRAINTS25/05/2026 02:50:50 PM
Updated system normal constraints to manage Murraylink dynamic rating forecast in pre-dispatch and PASA
Refer to Market Notice 134696
AEMO has now completed the production of the Murraylink dynamic rating forecast model and the forecasting performance has been satisfactory during the test. AEMO will be enabling the pre-dispatch and PASA formulation using the Murraylink dynamic rating forecast on the following two constraint equations at 1000 hrs on Wednesday 27th May 2026.
VSML_RAT_LIM_DYN
SVML_RAT_LIM_DYN
For full details on the formulation, the updated constraint equations have now been loaded into AEMO's pre-production systems.
Terry Liu
AEMO Operations
AEMO has now completed the production of the Murraylink dynamic rating forecast model and the forecasting performance has been satisfactory during the test. AEMO will be enabling the pre-dispatch and PASA formulation using the Murraylink dynamic rating forecast on the following two constraint equations at 1000 hrs on Wednesday 27th May 2026.
VSML_RAT_LIM_DYN
SVML_RAT_LIM_DYN
For full details on the formulation, the updated constraint equations have now been loaded into AEMO's pre-production systems.
Terry Liu
AEMO Operations
144083CONSTRAINTS15/05/2026 11:20:34 AM
Updated maximum generation contingency size in Victoria from 600 MW to 750 MW
VicGrid has conducted studies and determined that the maximum generation contingency size in Victoria can be increased from 600 MW to 750 MW.
This change affects the generator limitations for prior outage conditions especially in the South-west Victoria area. The new generation limitation for outages is now 750 MW. AEMO has implemented this change in production on 13th May 2026 by updating generation constraints to increase the generation upper limits for outage conditions.
Please refer to the Network Outage Schedule for any upcoming outages in south-west Victoria here.
https://www.aemo.com.au/energy-systems/electricity/national-electricity-market-nem/data-nem/network-data/network-outage-schedule
For further details on this change please refer to VicGrid Limits Advice or contact VicGrid.
vicgrid.com.au/transmission-planning/planning-the-energy-grid
Terry Liu
AEMO Operations
This change affects the generator limitations for prior outage conditions especially in the South-west Victoria area. The new generation limitation for outages is now 750 MW. AEMO has implemented this change in production on 13th May 2026 by updating generation constraints to increase the generation upper limits for outage conditions.
Please refer to the Network Outage Schedule for any upcoming outages in south-west Victoria here.
https://www.aemo.com.au/energy-systems/electricity/national-electricity-market-nem/data-nem/network-data/network-outage-schedule
For further details on this change please refer to VicGrid Limits Advice or contact VicGrid.
vicgrid.com.au/transmission-planning/planning-the-energy-grid
Terry Liu
AEMO Operations
134696CONSTRAINTS10/03/2026 12:18:10 PM
New system normal constraints to manage Murraylink real time dynamic rating
AEMO and APA have been working on better ways to reflect Murraylink transfer capability more accurately during high ambient temperature conditions. APA has supplied AEMO with a real time dynamic rating and AEMO will apply this in new constraint equations to dispatch Murraylink.
At this stage, the constraint equations will only be active in Dispatch timeframe.
The following two constraint equations will be implemented in constraint set V-NIL and S-NIL, at 1000 hrs on Thursday 12th March 2026:
VSML_RAT_LIM_DYN
SVML_RAT_LIM_DYN
For full details on the formulation, the new constraint equations have now been loaded into AEMO's pre-production systems.
Terry Liu
AEMO Operations
At this stage, the constraint equations will only be active in Dispatch timeframe.
The following two constraint equations will be implemented in constraint set V-NIL and S-NIL, at 1000 hrs on Thursday 12th March 2026:
VSML_RAT_LIM_DYN
SVML_RAT_LIM_DYN
For full details on the formulation, the new constraint equations have now been loaded into AEMO's pre-production systems.
Terry Liu
AEMO Operations
131890RESERVE NOTICE19/12/2025 05:14:42 PM
Cancellation of Actual (LOR2) condition in the NSW region - 19/12/2025
AEMO ELECTRICITY MARKET NOTICE
Cancellation of Actual (LOR2) condition in the NSW region - 19/12/2025
The Actual LOR2 Condition in the NSW Region advised in AEMO Electricity Market Notice No.131880 is cancelled at 1715 hrs 19/12/2025.
Manager NEM Real Time Operations
Cancellation of Actual (LOR2) condition in the NSW region - 19/12/2025
The Actual LOR2 Condition in the NSW Region advised in AEMO Electricity Market Notice No.131880 is cancelled at 1715 hrs 19/12/2025.
Manager NEM Real Time Operations
131880RESERVE NOTICE19/12/2025 04:11:12 PM
Actual Lack Of Reserve Level 2 (LOR2) in the NSW region - 19/12/2025
AEMO ELECTRICITY MARKET NOTICE
Actual Lack Of Reserve Level 2 (LOR2) in the NSW region - 19/12/2025
An Actual LOR2 condition has been declared under clause 4.8.4(b) of the National Electricity Rules for the NSW region from 1600 hrs.
The Actual LOR2 condition is forecast to exist until 19/12/2025 1700 hrs
The capacity reserve required is 700 MW
The minimum reserve available is 664 MW
AEMO is seeking an immediate market response.
An insufficient market response may require AEMO to implement a AEMO intervention event.
Manager NEM Real Time Operations
Actual Lack Of Reserve Level 2 (LOR2) in the NSW region - 19/12/2025
An Actual LOR2 condition has been declared under clause 4.8.4(b) of the National Electricity Rules for the NSW region from 1600 hrs.
The Actual LOR2 condition is forecast to exist until 19/12/2025 1700 hrs
The capacity reserve required is 700 MW
The minimum reserve available is 664 MW
AEMO is seeking an immediate market response.
An insufficient market response may require AEMO to implement a AEMO intervention event.
Manager NEM Real Time Operations
131795RESERVE NOTICE18/12/2025 07:14:14 PM
Cancellation of Actual (LOR2) condition in the NSW region - 18/12/2025
AEMO ELECTRICITY MARKET NOTICE
Cancellation of Actual (LOR2) condition in the NSW region - 18/12/2025
The Actual LOR2 Condition in the NSW Region advised in AEMO Electricity Market Notice No.131794 is cancelled at 1915 hrs 18/12/2025.
Manager NEM Real Time Operations
Cancellation of Actual (LOR2) condition in the NSW region - 18/12/2025
The Actual LOR2 Condition in the NSW Region advised in AEMO Electricity Market Notice No.131794 is cancelled at 1915 hrs 18/12/2025.
Manager NEM Real Time Operations
131794RESERVE NOTICE18/12/2025 05:58:18 PM
Actual Lack Of Reserve Level 2 (LOR2) in the NSW region - 18/12/2025
AEMO ELECTRICITY MARKET NOTICE
Actual Lack Of Reserve Level 2 (LOR2) in the NSW region - 18/12/2025
An Actual LOR2 condition has been declared under clause 4.8.4(b) of the National Electricity Rules for the NSW region from 1730 hrs.
The Actual LOR2 condition is forecast to exist until 18/12/2025 1800 hrs
The capacity reserve required is 700 MW
The minimum reserve available is 673 MW
AEMO is seeking an immediate market response.
An insufficient market response may require AEMO to implement a AEMO intervention event.
Manager NEM Real Time Operations
Actual Lack Of Reserve Level 2 (LOR2) in the NSW region - 18/12/2025
An Actual LOR2 condition has been declared under clause 4.8.4(b) of the National Electricity Rules for the NSW region from 1730 hrs.
The Actual LOR2 condition is forecast to exist until 18/12/2025 1800 hrs
The capacity reserve required is 700 MW
The minimum reserve available is 673 MW
AEMO is seeking an immediate market response.
An insufficient market response may require AEMO to implement a AEMO intervention event.
Manager NEM Real Time Operations
131662CONSTRAINTS15/12/2025 02:40:31 PM
Management of Over-Frequency conditions in South Australia
AEMO ELECTRICITY MARKET NOTICE
AEMO has conducted technical assessments to evaluate the adequacy of existing over-frequency generator shedding (OFGS) scheme in South Australia. The OFGS scheme helps to maintain frequency operating standards by tripping generators in a pre-determined manner during over-frequency conditions, to minimise the risk of cascade tripping.
AEMO?s review found that system security risks can arise when high levels of power transfer out of SA coincide with periods when the available OFGS capacity is insufficient to manage potential over-frequency conditions for a non-credible trip of the Heywood interconnector. As such a system normal constraint is required to manage the combined SA export capacity under such conditions, so as to maintain SA power system operations within the limits advised by ElectraNet.
The following constraint equation was implemented at 1425hrs 15 December 2025:
S_V_HEYWOOD_OFGS
Ben Blake
AEMO Operations
AEMO has conducted technical assessments to evaluate the adequacy of existing over-frequency generator shedding (OFGS) scheme in South Australia. The OFGS scheme helps to maintain frequency operating standards by tripping generators in a pre-determined manner during over-frequency conditions, to minimise the risk of cascade tripping.
AEMO?s review found that system security risks can arise when high levels of power transfer out of SA coincide with periods when the available OFGS capacity is insufficient to manage potential over-frequency conditions for a non-credible trip of the Heywood interconnector. As such a system normal constraint is required to manage the combined SA export capacity under such conditions, so as to maintain SA power system operations within the limits advised by ElectraNet.
The following constraint equation was implemented at 1425hrs 15 December 2025:
S_V_HEYWOOD_OFGS
Ben Blake
AEMO Operations