Transmission Equipment Ratings
GENERAL
Network equipment operating ratings are provided to AEMO by asset owners. The ratings may be provided as static data for use under specified conditions, telemetered dynamic real time data for use in dispatch timeframe, or may be hand dressed by AEMO in urgent circumstances.
Rating data used by AEMO is defined by equipment identifiers, a number of rating application levels, and rating application rules:
- Equipment identifiers are described in section 2.
- Rating application levels are described in section 3.
- Application rules are described in section 4.
Asset owners may provide additional information.
The basic structure employed in AEMO network modelling includes provision for multiple points of rating application on any transmission element. The structure allows for the application of a rating at both ends of the element and allows for flow in both directions. In addition to this, a number of levels of rating are accommodated to allow for different operating scenarios.
The data on this webpage and linked documents is provided subject to this Disclaimer.
EQUIPMENT IDENTIFIERS
The equipment identifiers included in the published static ratings information are those used in the AEMO ESCA SCADA system. They are as follows.
Site Name - The Substation, Terminal Station, or Power Station name.
Plant Type - Transmission Lines may be Line, Tie, Summ for summated lines, or S_REACT for series reactors. Transformers may be Trans, Tx, or Tf.
Plant ID - The equipment identifier.
Region - The NEM region.
Measurement - All values included in the publication process are MVA quantities.
Level - NORM, EMER, or LDSH as described in section 3 below.
Alternate Value - An identifier which describes when the rating is applicable, such as summer, winter, etc. Alternate Value application rules at the time of publication of this document are described in section 3 below. Note that any rating with an associated Alternate Value suffix of '_DYN' has a real time telemetered rating supplied by the asset owner. This telemetered value would normally be the rating applied in real time processes. If telemetered data is available, any associated static ratings will be used for predispatch, and for dispatch only on telemetered data failure.
Low and High - The low and high provide a directional feature in the application of the rating. When associated with the Site Name, the Low and High are interpreted using the convention of :
A positive value is power flow from the Site into the equipment.
The rating application levels applied by AEMO are defined below.
3.1 NORM
A continuous rating value. The NORM value is applied under pre-contingent conditions. This applies to security analysis and constraint equation application. This alarm level is used in monitoring and control of actual power flow through equipment without considering contingent events. For transformers the rating applied to this alarm level may be a fixed constant rating or the peak value of a continuous cyclic rating where the cyclic rating is comparable to the equipment loading profile.
Any continuous ratings provided for this purpose will be assumed valid by AEMO unless otherwise advised by NSP control room staff.
3.2 EMER
A rating value to be applied for a sustained period in emergency conditions. The EMER value is applied under post-contingent conditions. This applies to security analysis and constraint equation application. This alarm level is used in monitoring and control of actual power flow through equipment following the occurrence of a contingent event. For transformers the rating applied to this alarm level may be a fixed constant rating or the peak value of an 'emergency use' cyclic rating where the cyclic rating is comparable to the equipment loading profile.
The Emergency rating is subject to the NSP's assessment of the impact of the prevailing operating conditions and known ambient weather conditions at the time. When requested, the TNSP will assess the amount of EMER rating that is available for use in emergency conditions.
The same rating value as used for the NORM level of alarm will be used in this place if no value is supplied by a NSP.
3.3 LDSH
A short time rating. The LDSH value is applied under post-contingent conditions. The LDSH limit applies to security analysis and selected constraint equation application. This alarm level is used in monitoring and control of actual power flow through equipment following the occurrence of a contingent event.
Any short time ratings provided for this purpose will be assumed valid by AEMO unless otherwise advised by NSP control room staff.
The same rating value as used for the EMER level of alarm will be used in this place if no value is supplied by a NSP.
- Transmission Line or Cable Definition:
A short time transmission line or cable rating. The minimum time applicable is 15 minutes. A time greater than 15 minutes for lines or cables may be provided by an NSP however this nominated time must be consistent within the NSP boundary.
Note that a NSP may supply shorter time based rating values to be applied in specific agreed circumstances such as those included in contingency plans. Time based values of less than 15 minutes will be dealt with independently and will not be entered into the ESCA LDSH data fields for routine application. - Transformer Definition:
A short time transformer rating. Nominal time applicable is 2 hours. For distribution transformers times other than 2 hours may be provided by a NSP however this nominated time should be consistent within the NSP boundary. For main grid tie transformers times other than 2 hours may be provided by a NSP on a case by case basis as required for routine operational purposes.
ALTERNATIVE VALUE APPLICATION RATINGS
4.1 Queensland Transmission Assets
Asset Owners based in Queensland apply seasonal alternate ratings and dynamic ratings as shown below.
2 Season Day Night
Summer Day - (QLD_SUM_D) 06:00 - 18:00 Start of October to End of April
Summer Night - (QLD_SUM_N) 18:00 - 06:00 Start of October to End of April
Winter Day - (QLD_WIN_D) 06:00 - 18:00 Start of May to End of September
Winter Night - (QLD_WIN_N) 18:00 - 06:00 Start of May to End of September3 Season
Winter - (QLDWIN) Start of June to End of August
Spring/Aut - (QLDAUT/SPR) September Start of April to End of May
Summer - (QLDSUM) Start of October to End of MarchDynamic Telemetered Ratings
Dynamic ratings are available for selected circuits. These ratings are telemetered as a real time quantity to AEMO for use in the dispatch timeframe.
4.2 New South Wales Transmission Assets
Asset Owners based in New South Wales apply seasonal alternate ratings as shown below.
Summer / Winter (for cables)
Summer - (NSWSUM_C) Start of November to End of April
Winter - (NSWWIN_C) Start of May to End of October
Summer - (EA_SUM_C) Start of November to End of April
Winter - (EA_WIN_C) Start of May to End of OctoberSummer / Winter (for lines, transformers and outdoor switchgear)
Summer - (NSWSUM) Start of October to End of March
Winter - (NSWWIN) Start of April to End of September
Summer - (EA_SUM) Start of November to End of March
Winter - (EA_WIN) Start of April to End of October2 Seasons Day Night
Summer Day - (EA_SUM_D) 07:00 – 19:00 Start of October to End of April
Summer Night - (EA_SUM_N) 19:00 – 07:00 Start of October to End of April
Winter Day - (EA_WIN_D) 07:00 – 18:00 Start of May to End of September
Winter Night - (EA_WIN_N) 18:00 – 07:00 Start of May End of September3 Season Day Night
Summer Day - (N_SUM_D) 05:00 - 19:00 Start of December to End of February
Summer Night - (N_SUM_N) 19:00 - 05:00 Start of December to End of February
Spr/Aut Day - (N_AUT/SPR_D) 06:00 - 18:00 Start of September to End of Nov. 06:00 - 18:00 Start of March to End of May
Spr/Aut Night - (N_AUT/SPR_N) 18:00 - 06:00 Start of September to End of Nov.
18:00 - 06:00 Start of March to End of May
Winter Day - (N_WIN_D) 07:00 - 17:00 Start of June to End of August
Winter Night - (N_WIN_N) 17:00 - 07:00 Start of June to End of AugustMonthly Day Night
January Day - (JAN_DAY) 05:00 - 19:00 Start of January to End of January
January Night - (JAN_NIGHT) 19:00 - 05:00 Start of January to End of January
February Day - (FEB_DAY) 05:00 - 19:00 Start of February to End of February
February Night - (FEB_NIGHT) 19:00 - 05:00 Start of February to End of February
March Day - (MAR_DAY) 06:00 - 18:00 Start of March to End of March
March Night - (MAR_NIGHT) 18:00 - 06:00 Start of March to End of March
April Day - (APR_DAY) 06:00 - 18:00 Start of April to End of April
April Night - (APR_NIGHT) 18:00 - 06:00 Start of April to End of April
May Day - (MAY_DAY) 06:00 - 18:00 Start of May to End of May
May Night - (MAY_NIGHT) 18:00 - 06:00 Start of May to End of May
June Day - (JUN_DAY) 07:00 - 17:00 Start of June to End of June
June Night - (JUN_NIGHT) 17:00 - 07:00 Start of June to End of June
July Day - (JUL_DAY) 07:00 - 17:00 Start of July to End of July
July Night - (JUL_NIGHT) 17:00 - 07:00 Start of July to End of July
August Day - (AUG_DAY) 07:00 - 17:00 Start of August to End of August
August Night - (AUG_NIGHT) 17:00 - 07:00 Start of August to End of August
September Day - (SEP_DAY) 06:00 - 18:00 Start of September to End of Sept
September Night - (SEP_NIGHT) 18:00 - 06:00 Start of September to End of Sept
October Day - (OCT_DAY) 06:00 - 18:00 Start of October to End of October
October Night - (OCT_NIGHT) 18:00 - 06:00 Start of October to End of October
November Day - (NOV_DAY) 06:00 - 18:00 Start of November to End of Nov.
November Night - (NOV_NIGHT) 18:00 - 06:00 Start of November to End of Nov.
December Day - (DEC_DAY) 0500 - 19:00 Start of December to End of Dec.
December Night - (DEC_NIGHT) 19:00 - 05:00 Start of December to End of Dec.
4.3 Victorian Transmission Assets
Asset Owners based in Victoria apply seasonal alternate ratings, temperature based ratings and dynamic ratings as shown below.
2 Season
Summer - VICSUM) Start of November to End of April
Winter - (VICWIN) Start of May to End of October3 Season Day Night
Summer Day - (V_SUM_D) 06:00 - 21:00 Start of November to End of March
Summer Night - (V_SUM_N) 21:00 - 06:00 Start of November to End of March
Spr/Aut Day - (V_AUT/SPR_D) 06:00 - 21:00 Start of September to End of Oct. 06:00 - 21:00 Start of April to End of May
Spr/Aut Night - (V_AUT/SPR_N) 21:00 - 06:00 Start of September to End of Oct. 21:00 - 06:00 Start of April to End of May
Winter Day - (V_WIN_D) 07:00 - 19:00 Start of June to End of August
Winter Night - (V_WIN_N) 19:00 - 07:00 Start of June to End of AugustTemperature Based Ratings
Temperature based ratings are available for selected circuits. Selection is based on ambient temperatures with 5 degree steps from 5 degrees to 45. The temperature is telemetered as a real time quantity to AEMO for use in the dispatch timeframe. Predefined temperature profiles are applied to the predispatch timeframe.
Please refer to the Victorian Temperature profiles. These profiles are applied in AEMO applications and the same temperature profiles are repeated each year.Dynamic Telemetered Ratings
Dynamic ratings are available for selected circuits. These ratings are telemetered as a real time quantity to AEMO for use in dispatch timeframe.
4.4 South Australian Transmission Assets
Asset Owners based in South Australia apply seasonal alternate ratings and dynamic ratings as shown below.
3 Season (for future timeframe)
Winter - (SAWIN) Start of June to End of August
Spring/Aut - (SAAUT/SPR) Start of March to End of May / Start of September to End of November
Summer - (SASUM) Start of December to End of February3 Season (for dispatch timeframe)
A selection indicator is telemetered to AEMO for the seasonal ratings used in the dispatch timeframe. The selection of particular seasonal ratings is managed by this telemetered indicator (1, 2, or 3) provided by the asset owner as shown below.
Winter - (SAWIN) < 20 degrees
Spring/Aut - (SAAUT/SPR) > 20 & < 30
Summer - (SASUM) > 30 degreesDynamic Telemetered Ratings
Dynamic ratings are available for selected circuits. These ratings are telemetered as a real time quantity to AEMO for use in dispatch timeframe.
4.5 Tasmanian Transmission Assets
Asset Owners based in Tasmania apply seasonal alternate ratings, temperature based ratings and dynamic ratings as shown below.
2 Season
Summer - (TASSUM) Start of Dec to End of Feb
Winter - (TASWIN) Start of March to End of NovemberTemperature Based Ratings
Temperature based ratings are available for selected circuits. Selection is based on ambient temperatures with 5 degree steps from 0 degrees to 40 degrees. The temperature is telemetered as a real time quantity to AEMO for use in the dispatch timeframe. Predefined temperature profiles are applied to the predispatch timeframe. Please refer to Tasmanian Temperature profiles. These profiles are applied in AEMO applications and the same temperature profiles are repeated each year.
Dynamic Telemetered Ratings
Dynamic ratings are available for selected circuits. These ratings are telemetered as a real time quantity to AEMO for use in dispatch timeframe.
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