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

Cancellation: Direction issued to: Origin Energy Electricity Limited - QUARANTINE PS UNIT 5

Refer to Market Notice 144169

Direction is cancelled from: 2315 hrs 31/05/2026

Manager NEM Real Time Operations

AEMO ELECTRICITY MARKET NOTICE

Cancellation - AEMO Intervention Event - SA region 31/05/2026

Refer to Market Notice 144170

The AEMO Intervention Event and all associated directions are cancelled from 2315 hrs on 31/05/2026.


Manager NEM Real Time Operations

AEMO ELECTRICITY MARKET NOTICE

Direction - SA region 31/05/2026

In accordance with section 116 of the National Electricity Law, AEMO has issued a direction to a participant in the SA region. For the purposes of the National Electricity Rules this is a direction under clause 4.8.9(a1)(1).

The issue of the direction commences an AEMO intervention event. AEMO declares all trading intervals during the event to be intervention trading intervals, commencing from the interval ending 2150 hrs on 31/05/2026.

Intervention pricing does not apply to this AEMO intervention event.

AEMO may issue or revoke additional directions in order to meet the current requirement, unless sufficient market response is provided. A further market notice will be issued when all directions related to this requirement have been cancelled.


Manager NEM Real Time Operations

AEMO ELECTRICITY MARKET NOTICE

Direction - in SA region to Origin Energy Electricity Limited - QUARANTINE PS UNIT 5

In accordance with section 116 of the National Electricity Law, AEMO is issuing a direction to Origin Energy Electricity Limited. For the purposes of the National Electricity Rules this is a direction under clause 4.8.9(a1)(1).

Direction issued to: Origin Energy Electricity Limited - QUARANTINE PS UNIT 5 at 2145hrs 31/05/2026
Type of resource: generating unit
Required actions: Remain Synchronised and follow dispatch targets at 2200 hrs 31/05/2026
Services provided: Voltage Control
Circumstances necessitating the Direction: Voltage
Circumstances necessitating the Direction additional detail: The synchronous generating units currently expected to be synchronised in SA will be inadequate to maintain sufficient Voltage Control in SA. Intervention is required to maintain the power system in a secure operating state
Expected duration: 2330 hrs 31/05/2026.

Origin Energy Electricity Limited does not incur any civil monetary liability for a relevant action taken in accordance with this direction unless the action is taken in bad faith.

Manager NEM Real Time Operations

AEMO ELECTRICITY MARKET NOTICE

Inter-regional transfer limit variation - Heywood M1 500/275kV XFMR - VIC region - 29/05/2026

A planned outage of Heywood M1 500/275kV XFMR in the VIC region was scheduled from 1100 hrs 25/05/2026 to 1800 hrs 29/05/2026.

The outage has been completed and Heywood M1 500/275kV XFMR returned to service at 0920 hrs 29/05/2026

Constraint set(s) revoked: V-HYTX_M12

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

Inter-regional transfer limit variation - Koorangie to Wemen 220 kV Line - VIC region - 25/05/2026

At 1130 hrs 25/05/2026 there was a short notice outage of Koorangie to Wemen 220 kV Line.

The following constraint set(s) invoked at 1130 hrs 25/05/2026
V-KOWE

This constraint set(s) contains equations with the following interconnectors on the LHS.
V-S-MNSP1,T-V-MNSP1,V-SA,VIC1-NSW1

Refer to the AEMO Network Outage Scheduler for further information.

Manager NEM Real Time Operations

AEMO ELECTRICITY MARKET NOTICE

Inter-regional transfer limit variation - Tailem Bend 275 kV East Bus - SA region - 24/05/2026

At 1250 hrs 24/05/2026 there was a short notice outage of Tailem Bend 275 kV East Bus.

The following constraint set(s) invoked at 1250 hrs 24/05/2026
S-TB275_E_BUS

This constraint set(s) contains equations with the following interconnectors on the LHS.
V-SA

Refer to the AEMO Network Outage Scheduler for further information.

Manager NEM Real Time Operations