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Non-credible contingency event - Qld region - 01/04/2023
Non-credible contingency event - Qld region - 01/04/2023
At 2109 hrs ,
- Feeder 877 Woree -Tumoulin 275 kV - tripped and auto reclosed
- Feeder 7166 Chalumbin - Turkinje 132 kV - Tripped and auto reclosed
- Feeder 7143 Kamerunga - Barron Gorge - Tripped
AEMO did not instruct load shedding.
AEMO was advised of disconnection of bulk electrical load of 30 MW.
The cause of this non credible contingency event is not known at this stage.
Manager NEM Real Time Operations
Update - Non-credible contingency event - TAS region - 27/03/2023
Update - Non-credible contingency event - TAS region - 27/03/2023
Refer AEMO Electricity market notice 106999
At 1040 hrs the Sheffield - Palmerston 220kV line tripped at the Palmerston end only.
The cause of this non credible contingency event is not known at this stage.
AEMO is not satisfied that this non credible event is unlikely to re-occur.
AEMO has therefore reclassified this event as a credible contingency event until further notice.
Region: Tas
Duration: 1227/03/2023 16:20 until further notice
Constraint set(s) invoked: Nil
Manager NEM Real Time Operations
Non-credible contingency event - TAS region - 27/03/2023
Non-credible contingency event - TAS region - 27/03/2023
At 1040 hrs the Sheffield - Palmerston 220kV line tripped at the Palmerston end only.
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 - SA region - 23/03/2023
Non-credible contingency event - SA region - 23/03/2023
At 1113 hrs the South East SVC 1 and SVC 2 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 to Victorian system normal constraint equations ID
AEMO has been conducting major review of thermal constraint equations for preparation of completion of VNI East project. As part of the review, AEMO is going to update the constraint equations IDs to use the new standard format of below (this is the same standard now used in NSW):
V>>[OUTAGE]_[MONITORING ELEMENT]_[CONTINGENCY ELEMENT]
This is to improve the simplicity and readability of a thermal constraint equation ID.
Constraint equations ID in sets V-NIL and V-NIL_BATS_BETS_15M will be updated to the new format on Thursday 23rd March 2023 at 1000 hrs. The previous used constraint equations ID will be included in the Modification field of the constraint equation for reference.
The changes have now been implemented into AEMO's pre-production system.
Terry Liu
AEMO Operations
Updated NSW system normal voltage stability limit
Refer to market notice 105936?
The Murraylink Very Fast Runback (VFRB) scheme was modified to increase the capacity of the network due to the increase in generation in the area. The scheme was changed so Murraylink VFRB could be activated / de-activated depending on the time of day on the monitored 220kV lines in north-west Victoria.?
Transgrid has advised AEMO on a revision to the X5 voltage collapse limit with this change to VFRB. This will now be managed by two limits.?
The following constraint equation changes will be implemented at 0900 hrs on Thursday 16th March 2023:
N^^N_NIL_X5_BEKG (replaces N^^N_NIL_3)
N^^N_NIL_X5_BESH (new)?
For full details on the factors on constraint equations and all the constraint equation changes - these have now been loaded into AEMO's pre-production systems.?
Ben Blake
AEMO Operations
Update to system strength requirements in North Queensland
Refer to market notice 102074
AEMO and Powerlink are continuing to investigate system strength requirements in North Queensland.
Due to commissioning of Kaban wind farm in Far North Queensland, the system normal equations have been revised to include following combinations.
-If Stanwell >=2, Stanwell + Calllide >=3, Gladstone >= 1, Stanwell + Callide + Gladstone >= 7, Kareeya >=0, Haughton Syncon status = ON/OFF, North Queensland load >=250 MW,
Ross+FNQ load >=100 MW, limit Kaban Windfarm to 100% (with Haughton Syncon ON), 0% (with Haughton Syncon Syncon OFF) and no limit to other NQLD Plants.
A revision to the constraint equations will be implemented at 1400 hrs on Wednesday 1st March 2023.
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_XXXX
Q_NIL_STRGTH_XXXX_I
AEMO Operations
Changes to Murraylink Very Fast Runback and constraints in Victoria
The Murraylink Very Fast Runback (VFRB) scheme is being modified to increase the capacity of the network due to the increase in generation in the area. The scheme will be changed so Murraylink VFRB can be activated / de-activated depending on the time of day on the monitored 220kV lines in north-west Victoria.
The changes to the scheme will be activated and constraint equaiton modified at 1200hrs Monday 20th February 2023. The following system normal constraint equations will be modified:
V^^V_NIL_KGTS
V^^V_NIL_KGTS_2
V>>SML_NIL_7A
V>>SML_NIL_7B
V>>SML_NIL_7C
V>>V_NIL_13
V>>V_NIL_14
V>>V_NIL_20
V>>V_NIL_21
V>>V_NIL_22
V>>V_NIL_23
V>>V_NIL_24
V>>V_NIL_25
V>>V_NIL_26
V>>V_NIL_26_1
V>>V_NIL_26A
V>>V_NIL_26A_1
For full details on the factors on constraint equations and all the constrint equation changes - these have now been loaded into AEMO's pre-production systems.
Ben Blake
AEMO Operations
Non-credible contingency event - Qld Region - 13/02/2023
Non-credible contingency event - Qld Region - 13/02/2023
At 1402 hrs 13/02/2023 the H77 Columboola - H76 Wandoan South No. 8891 and No. 8892 275 kV Lines tripped, also affecting supply west of H79 Yuleba North and H80 Eurombah.
AEMO did not instruct load shedding.
Approximately 390 MW of Load interrupted and 114 MW of Generation interrupted.
The cause of this non credible contingency event is not known at this stage.
Manager NEM Real Time Operations