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Update to system strength requirements in North Queensland
Refer to market notice 106175
AEMO and Powerlink are continuing to investigate system strength requirements in North Queensland.
Due to commissioning of Clarke Creek wind farm in Far North Queensland, the system normal equations have been revised.
A revision to the constraint equations will be implemented at 1100 hrs on Monday 9th December 2024.
The new combinations have now published in a limits advice document on AEMO's website. For more information refer to the new limits advice: https://www.aemo.com.au/energy-systems/electricity/national-electricity-market-nem/system-operations/congestion-information-resource/limits-advice
This advice contains all the combinations for Queensland for system normal cases. Additional information has been included in the limit advice to clarify the requirement to disconnect all inverters/turbines under certain system conditions.
The constraint equation in the Q-NIL set of the form below will be modified:
-Q_NIL_STRGTH_KBWF
-Q_NIL_STRGTH_MEWF
Two new equations have been added:
-Q_NIL_STRGTH_CKWF
-Q_NIL_STRGTH_CKWF_I
AEMO Operations
Non-credible contingency event - NSW region - 26/11/2024
Non-credible contingency event - NSW region - 26/11/2024
At 1637 hrs Uranquinty Unit 12 tripped and at 1639 hrs Uranquinty Units 11 and 13 tripped.
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
Update - Non-credible contingency event - VIC region - 12/11/2024
Update - Non-credible contingency event - VIC region - 12/11/2024
Refer AEMO Electricity Market Notice 120305
At 1135 hrs the Yallourn No 1 220 kV 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
Non-credible contingency event - VIC region - 12/11/2024
Non-credible contingency event - VIC region - 12/11/2024
At 1041 hrs the Yallourn No 1 220 kV bus and Yallourn Unit 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
Update - Non-credible contingency event - NSW region - 31/10/2024
Update - Non-credible contingency event - NSW region - 31/10/2024
Refer AEMO Electricity Market Notice 119689
At 0345 hrs the Wagga B 330 kV 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
Non-credible contingency event - NSW region - 31/10/2024
Non-credible contingency event - NSW region - 31/10/2024
At 0028 hrs the Wagga B 330 kV bus tripped which offloaded the Wagga - Walla Walla SF 6Y 330 kV line and Wagga No.3 transformer.
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
Non-credible contingency event - VIC region - 18/10/2024
Non-credible contingency event - VIC region - 18/10/2024
At 1525 hrs the Rowville - Yallourn No. 7 220 kV Line and the Rowville - Yallourn No. 8 220 kV Line tripped and auto-reclosed.
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
Managing outages that create a credible risk of SA islanding
From 9th Oct 2024 AEMO will change constraints used during outages that create a credible risk of SA islanding.
From this date AEMO will:
1) Increase the maximum allowable flow on the V-SA interconnector from 50 MW to 250 MW in the VIC to SA direction, where the transmission outages is a planned outage.
2) Operate the SA region to the default 49-51 Hz target frequency containment band following a contingency event resulting in actual SA islanding. In order to meet this requirement, AEMO may now procure Contingency Raise FCAS locally from the SA region during these outages.
These changes reflect updated advice received by AEMO from the SA Jurisdictional System Security Coordinator.
The first network outage affected by this change is planned for 14th October 2024.
Andrew Groom
AEMO Operations
Update to system normal constraint equation in NSW for transient voltage stability in south-west NSW
Refer to market notice 92840.
Transgrid has advised AEMO of an update to the transient voltage stability limit in south-west NSW for loss of Darlington Point to Wagga (63) 330 kV line. The limit will include terms for the Darlington Point and Riverina BESS.
The following constraint equation will be updated with the above changes at 1100 hrs Friday 20th September 2024.
N::N_NIL_63
For full details on the formulation, the new constraint equation has now been loaded into AEMO's pre-production systems.
For further details on these constraint equation please contact ben.blake@aemo.com.au
Ben Blake
AEMO Operations