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New system normal constraint equations for thermal overload in south west Victoria
AEMO has reviewed the thermal limits in south west Vic with the recent addition of new generators in the area. With a further increase in generation capacity in south west Victoria AEMO has identified potential thermal issues on the south west Victorian 500 kV network. AEMO will implement three new constraint equations which will manage loading on the Haunted Gully to Moorabool, Mortlake to Moorabool and Moorabool to Sydenham lines for other 500 kV line trips in south-west Victoria. These constraint equations are unlikely to bind until there is a further increase in generation in south-west Victoria.
The constraint equations include generators in western Victoria and the Heywood and Murraylink interconnectors on the left-hand side.
The following constraint equations will be implemented at 1000 hrs 30th October 2020.
V>>V_NIL_15
V>>V_NIL_16
V>>V_NIL_17
For full details on the factors these constraint equations have now been loaded into AEMO's pre-production systems.
For further details on these new constraint equations please contact ben.blake@aemo.com.au
Ben Blake
AEMO Operations
West Murray issue and limit on Murraylink
Refer to market notice 77189
Following further technical assessment of the issues impacting grid performance and operational stability in the West Murray region AEMO has identified that limiting the flow on the Murraylink interconnector from SA to Vic is no longer required.
The constraint set I-SVML_095 will be revoked at 1200 hrs on 15th Octber 2020.
Ben Blake
AEMO Operations
Update to Vic to NSW voltage collapse limit
Refer to market notice 77600
AEMO has completed work on a revised system normal voltage stability limit at Victoria for flows from Victoria to New South Wales. This limit is to manage voltage collapse around Murray for the loss of all APD potlines.
The constraint equation includes generators in south-west NSW and north-west Victoria on the left-hand side as well as VIC1-NSW1. Full details on the limits advice are published on the AEMO website: https://www.aemo.com.au/energy-systems/electricity/national-electricity-market-nem/system-operations/congestion-information-resource/limits-advice
The constraint is most likely to bind when there is low Vic demands and high transfers to NSW. When it binds it will restrict Vic to NSW transfers and southern NSW generation.
This revised limit will be implemented to the following constraint equation at 1000 hrs Friday 9th October 2020.
V^^N_NIL_1
For further details on this constraint equation please contact terry.liu@aemo.com.au
Terry Liu
AEMO Operations
Update to system strength requirements in North Queensland
Refer to market notice 77646
AEMO and Powerlink are continuing to investigate system strength requirements in North Queensland.
A revision to the constraint equations will be implemented at 0900 hrs Friday 9th October 2020.
The new combinations are 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.
The constraint equations in the Q-NIL set of the form below will be modified:
Q_NIL_STRGTH_XXX
For further details please contact James Lindley at james.lindley@aemo.com.au or Simon Taylor at businessdevelopment@powerlink.com.au
Mya San
AEMO Operations
New constraint for UFLS in South Australia
As part of a suite of recommendations to restore under frequency load shedding (UFLS) capability and mitigate risks, AEMO is updating and expanding existing network constraints to keep power flows across the Heywood interconnector within limits that allow South Australia's UFLS to operate effectively if needed.
The following constraint equation will be added to the South Australian system normal set at 1100 hrs Friday 9th October 2020.
V_S_HEYWOOD_ULFS
A fact sheet on the new constraint equation is available here: https://aemo.com.au/-/media/files/initiatives/der/2020/heywood-ufls-constraints-fact-sheet.pdf
Support Information:
For further details on this constraint equation please contact the AEMO Information and Support Hub supporthub@aemo.com.au or call 1300 236 600.
Ben Blake
AEMO Operations
Update to system strength requirements in North Queensland
Refer to market notice 76608
Powerlink have revised the strength requirements in North Queensland. AEMO has updated the related constraint equations and these will be implemented at 1000 hrs Friday 11th September 2020.
The new and revised combinations are now published in a limits advice document on AEMO's website: 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 and replaces all the previous advice.
The constraint equations in the Q-NIL set of the form below will be modified:
Q_NIL_STRGTH_XXX
For further details please contact James Lindley at james.lindley@aemo.com.au or Simon Taylor at businessdevelopment@powerlink.com.au
Ben Blake
AEMO Operations
Update to Vic to NSW voltage collapse limit
Refer to market notice 63893
AEMO is currently revising the existing voltage collapse constraint equation for Victoria to NSW transfers for the simultaneous loss of all APD potlines. The existing equation requires a review for record low Victorian demands and high transfers to NSW. To reduce the instances of AEMO invoking discretionary limits while this review is being completed an offset of 250 MW will be applied to the existing constraint equation.
This change will occur at 1400 hrs 9th September 2020.
The following constraint equation will be modified:
V^^N_NIL_1
For further details on this new constraint equation please contact ben.blake@aemo.com.au
Ben Blake
AEMO Operations
New West Murray issue and new limit on Murraylink
The West Murray region continues to be a challenging area to manage power system security. New technical issues impacting grid performance and operational stability have been identified following review of the Ararat to Crowlands 220 kV line trip on 20 August 2020.
To manage power system security AEMO will be limiting the flow on the Murraylink interconnector from SA to Vic to 95 MW. This will be implemented from 1200 hrs on 26 August 2020 with the following IDs:
Constraint Set ID: I-SVML_095
Constraint Equation ID: SVML_095
The limit will remain in place until 16 October 2020 unless otherwise notified. AEMO will provide updates on this matter as issues are further explored and potential solutions identified.
Ben Blake
AEMO Operations
Update to system strength requirements in North Queensland
Refer to market notice 76455
AEMO and Powerlink are continuing to investigate system strength requirements in North Queensland. A revision to the constraint equations will be implemented at 1400 hrs Wednesday 12th August 2020.
Combination 8 (in market notice 74655) has been updated to allow for 1 unit on at Callide B or Callide C (instead of 1 unit on at both).
The combination will be updated to:
8 - 2 x Stanwell, 1 x Callide B or 1 x Callide C, 3 x Gladstone, 7 x Total Stanwell+Callide+Gladstone, 2 x Kareeya: 100% output at Clare, Collinsville, Daydream, Hamilton, Hayman, Kidston, Ross, Rugby Run, Whitsunday
The constraint equations in the Q-NIL set of the form below will be modified:
Q_NIL_STRGTH_XXX
Q_NIL_STRGTH_XXX_I
For further details please contact James Lindley at james.lindley@aemo.com.au or Simon Taylor at businessdevelopment@powerlink.com.au
Ben Blake
AEMO Operations