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Update to Vic to NSW voltage collapse limit
Refer to Market Notice 78621
AEMO has completed a further review of the system normal voltage stability limit for loss of all APD potlines for flows from Victoria to New South Wales. The revised limit is the result of improved reactive modelling in southern NSW which could potentially mean higher transfers into NSW under some generation/load scenarios.
The revised constraint equation includes generators in southern NSW and hydro generation at Mt. Beauty on the left-hand side as well as VIC1-NSW1. Full details on the limits advice are to be published on 11/02/2021 on the AEMO website: https://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 Hume NSW unit.
This revised limit will be implemented to the following constraint equation at 1000 hrs Thursday 11th February 2021.
V^^N_NIL_1
For further details on this constraint equation please contact terry.liu@aemo.com.au
Terry Liu
AEMO Operations
Update to Voltage Stability limits for Murraylink transfers from South Australia to Victoria
ElectraNet has advised AEMO of revised voltage stability limits for Murraylink transfers from South Australia to Victoria.
Refer to Market Notice 82079.
The existing limit of 160 MW on Murraylink will be replaced with two voltage stability limits. Only one of the limits would apply depending on whether or not the Monash capacitor banks are available and in-service for switching.
The following constraint sets and equations will be implemented at 1000 hrs Wednesday 13th January 2021:
- constraint set S-NIL containing constraint equation SVML^NIL_MH-CAP_ON.
- constraint set S-MH_CAP (renamed from S-NIL_MN-CAP_OFF) containing constraint SVML^MH-CAP_OFF (renamed from SVML^NIL_MH-CAP_OFF).
Constraint set S-NIL will remain invoked at all times.
Constraint set S-MH_CAP will only be invoked when Monash Capacitors are not available for switching and are out of service or if one or both capacitors are out of service.
The existing equation SVML^NIL_160 in the S-NIL set will be removed.
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 diyoni.hoole@aemo.com.au.
Diyoni Hoole
AEMO Operations
Update to Voltage Stability limits for Murraylink transfers from South Australia to Victoria
ElectraNet has advised AEMO of revised voltage stability limits for Murraylink transfers from South Australia to Victoria.
The existing limit of 160 MW on Murraylink will be replaced with two voltage stability limits. Only one of the limits would apply depending on whether or not the Monash capacitor banks are available and in-service for switching.
The following constraint sets and equations will be implemented at 1000 hrs Wednesday 13th January 2021:
- constraint set S-NIL containing constraint equation SVML^NIL_MH-CAP_ON.
- constraint set S-NIL_MN-CAP_OFF containing constraint SVML^NIL_MH-CAP_OFF.
Constraint set S-NIL will remain invoked at all times.
Constraint set S-NIL_MN-CAP_OFF will only be invoked when Monash Capacitors are not available for switching and are out of service.
The existing equation SVML^NIL_160 in the S-NIL set will be removed.
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 diyoni.hoole@aemo.com.au.
Diyoni Hoole
AEMO Operations
Update to system strength requirements in North Queensland
Refer to market notice 80324
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 18th December 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 FCAS constraint equations for trip of generators in south-west NSW
In the event of a trip of the Darlington Point to Wagga (63) 330 kV line a number of generators will be tripped via a transfer tripping control scheme. With the increase in generation in south-west NSW AEMO has identified that the total MWs could potentially exceed the largest NSW generating unit. AEMO will implement new FCAS constraint equations to manage this contingency.
The constraint equations include the impacted generators: Broken Hill solar (BROKENH1), Darlington Point (DARLSF1), Limondale 1 (LIMOSF11), Sunraysia (SUNRSF1) and Silverton (STWF1) and regional FCAS requirements the left-hand side.
The following constraint equations will be implemented at 1000 hrs 4th December 2020.
F_I+TTS_TG_R5
F_I+TTS_TG_R6
F_I+TTS_TG_R60
F_MAIN++TTS_TG_R5
F_MAIN++TTS_TG_R6
F_MAIN++TTS_TG_R60
F_MAIN+TTS_TG_R5
F_MAIN+TTS_TG_R6
F_MAIN+TTS_TG_R60
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
Update to Far North Queensland Voltage Stability limits
Powerlink has advised AEMO of revised voltage stability limits in Far North Queensland.
The revised limits include
-an update to the existing limit for loss of Woree SVC and a new limit for loss of Mt Emerald Windfarm for system normal condition
-two new limits for network reconfiguration
The network is being reconfigured so existing 132 kV lines can be operated at 275 kV - forming the new Ross to Woree (8966) 275 kV feeder. This temporary arrangement is in place to allow for repairs to the Chalumbin to Woree 275kV (877) line.
The following constraint sets and equations will be implemented at 1300 hrs Thursday 3rd December 2020.
- constraint set Q-NIL_FNQ_NORM containing constraint equations Q^NIL_FNQ_MEWF and Q^NIL_FNQ_WRSVC.
- constraint set Q-NIL_FNQ_RECON containing constraint equations Q^NIL_FNQ_858MEWF and Q^NIL_FNQ_8966.
Only one of the above two sets will be invoked at any one time.
- Q-NIL_FNQ_RECON set will be invoked during Far North Queensland network reconfiguration.
- Q-NIL_FNQ_ NORM set will be invoked upon returning to the previous configuration once the repairs are completed in mid-2021.
The existing equation Q^NIL_FNQ in the Q-NIL set will be removed.
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 mya.san@aemo.com.au.
Mya San
AEMO Operations
Update to system strength requirements in North Queensland
Refer to market notice 79837
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 Thursday 26th November 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 system normal constraint equation in NSW for voltage collapse at Balranald
TransGrid has advised AEMO of a new voltage collapse limit in south west NSW, which is required to prevent voltage collapse at Balranald following a loss of a 220 kV line in north-west Victoria (either Bendigo to Kerang, Kerang to Wemen or Buronga to Red Cliffs lines). The limit applies to pre-contingent flow on Balranald to Darlington Point (X5) 220 kV line. The constraint equation is likely to bind when there is high generation in south-west NSW.
The constraint equation includes generators in south-west NSW and north-west Victoria on the left-hand side as well as Murraylink and VIC1-NSW1.
The following constraint equation will be implemented at 1000 hrs Friday 20th November 2020.
N^^N_NIL_3
For full details on the factors this constraint equation has now been loaded into AEMO's pre-production systems.
For further details on this new constraint equation please contact ben.blake@aemo.com.au
Ben Blake
AEMO Operations
Update to system strength requirements in North Queensland
Refer to market notice 78616
AEMO and Powerlink are continuing to investigate system strength requirements in North Queensland.
Following recent control setting changes at Mt Emerald wind farm the system strength limits on Mt Emerald wind farm, Sun Metals Solar farm and Haughton Soar Farm have been revised.
A revision to the constraint equations will be implemented at 0900 hrs Friday 13th November 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_HAUSF
Q_NIL_STRGTH_MEWF
Q_NIL_STRGTH_SMSF
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