Market Notices

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 ELECTRICITY MARKET NOTICE.

Update - Non-credible contingency event - QLD region - 29/05/2026

Refer AEMO Electricity Market Notice 144162

At 2135 hrs the Woolooga to Teebar Creek 8850 275kV Line and the Teebar Ck No2 275kV Bus was returned to service.

The cause of this non-credible contingency event has been identified and AEMO is satisfied that another occurrence of this event is unlikely under the current circumstances.

AEMO will not reclassify this event as a credible contingency event.

Manager NEM Real Time Operations

AEMO ELECTRICITY MARKET NOTICE.

Non-credible contingency event - QLD region - 29/05/2026

At 1013 hrs the Woolooga to Teebar Creek 8850 275kV Line and the Teebar Ck No2 275kV Bus tripped.

AEMO did not instruct load shedding.

AEMO has not been advised of any disconnection of bulk electrical load.


The cause of this non credible contingency event is not known at this stage.


Manager NEM Real Time Operations

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 ELECTRICITY MARKET NOTICE.

Update - Non-credible contingency event - NSW region - 17/05/2026

Refer AEMO Electricity Market Notice 144112

At 1327 hrs the Upper Tumut Units 1, 2, 3 and 4 were made available to return to service.

The cause of this non-credible contingency event has been identified and AEMO is satisfied that another occurrence of this event is unlikely under the current circumstances.

AEMO will not reclassify this event as a credible contingency event.

Manager NEM Real Time Operations

AEMO ELECTRICITY MARKET NOTICE.

Non-credible contingency event - NSW region - 17/05/2026

At 2317 hrs the Upper Tumut Units 1, 2, 3 and 4 tripped.

AEMO did not instruct load shedding.

AEMO has not been advised of any disconnection of bulk electrical load.

The cause of this non credible contingency event is not known at this stage.

Manager NEM Real Time Operations

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

AEMO ELECTRICITY MARKET NOTICE.

Update - Non-credible contingency event - QLD region - 13/05/2026

Refer AEMO Electricity Market Notice 144073

At 1341 hrs the T157 Ingham South No.1 and No.2 132/66kV Transformers were returned to service.

The cause of this non-credible contingency event has been identified and AEMO is satisfied that another occurrence of this event is unlikely under the current circumstances.

AEMO will not reclassify this event as a credible contingency event.

Manager NEM Real Time Operations

AEMO ELECTRICITY MARKET NOTICE.

Non-credible contingency event - QLD region - 13/05/2026

At 1255 hrs the T157 Ingham South No.1 and No.2 132/66kV Transformers tripped.

AEMO did not instruct load shedding.

AEMO estimates approximately 6MW of electrical load has been disconnected.

The cause of this non credible contingency event is not known at this stage.


Manager NEM Real Time Operations