The subtransmission line tables include the following information:

• Planning Region
  • Ergon Energy Ecorp Asset ID
  • Ergon Energy operational number
• Subtransmission line description
• Summer capacity & load forecasts for 5 years
  • Rating (Amps)
  • Loading (Amps)
  • Power Factor

Definitions

SD: Summer Day (9am to 5pm)
SE: Summer Evening (5pm to 10pm)
SNM: Summer Night/Morning (10pm to 9am)
Summer: December to March

Comments

• Poor power factors of some feeders
  Where the power factors are very low it is because (in general) the feeder is part of a ring network with circulating reactive power. The active power is swamped by the reactive power in these cases. There are some radial feeders where the power factor is also very low. This is as a result of very little active power being supplied by these feeders combined with a lot of line charging reactive power which once again swamps the active power component.
• Missing power factors
  This is a result of unloaded feeders that are only energised from one side. There is some line charging which accounts for the non-zero loading in amperes but there is no active power supplied by the feeder.

The Substation Forecast file has information on 5-year forecast capacity and loading information for each Ergon Energy owned Bulk Supply and Zone Substations.

Definitions

Peak Risk Period: The time period over which the load is highest (Summer/Winter).
NCC Rating (MVA): Normal Cyclic Capacity - the total capacity with all network components and equipment in service.
Contracted non-network (MVA): The amount of embedded generation and contracted curtailed demand management capacity available within the supply area of a substation during peak times. The impacts of these have been incorporated into the load forecasts. Solar PV connections are not included in the reported figure.
10 PoE Load (MVA): Peak load forecast with 10% probability of being exceeded (one in every 10 years will be exceeded). Based on normal expected growth rates and weather corrected starting loads.
LARn (MVA): Security standard load at risk under system normal condition, expressed in MVA.
LARn (MW): Security standard load at risk under system normal condition, expressed in MW.
Power Factor at Peak Load: Compensated power factor at 50 PoE Load.
ECC Rating (MVA): The maximum permissible peak emergency loading for a given load cycle that an item of plant can supply for an extended period of time without unacceptable damage. For substations with multiple transformers, the ECC is the minimum emergency cyclic capacity of all transformer combinations taking impedance mismatches into consideration, with one transformer offline.
50 PoE Load (MVA): Peak load forecast with 50% probability of being exceeded (one in every two years will be exceeded). Based on normal expected growth rates & weather corrected starting loads.
Hours PA > 95% Peak Load: The amount of load greater than 95% 50 PoE Load.
Raw LAR (MVA): The amount of load exceeding ECC rating. (Load – ECC Rating)
Auto Trans Avail (MVA): SCADA or automatically controlled load transfers that can be implemented within one minute.
Remote Trans Avail (MVA): Load transfers that can be implemented through SCADA switching procedures by the network control officer. It is assumed that this can generally be achieved within 30 minutes.
Manual Trans Avail (MVA): Load transfers can also be deployed via manually controlled switchgear locally by field staff.
Mobile Plant Avail (MVA): The capacity of mobile substation or mobile generation that can be deployed within the timeframe and capacity prescribed by the security standard.
Shed(30min): Loads to large customers which can be disconnected by remote operation of switchgear.
Shed(4Hour): Loads to large customers which need manual switching by field crews to disconnect them from the network.
Capacity for Embedded Generation(MVA): The total capacity for embedded generation to transfer power from lower voltage network to higher voltage network with all network components and equipment in service.
Firm Capacity for Embedded Generation (MVA): The firm capacity for embedded generation to transfer power from lower voltage network to higher voltage network under a single contingent condition.
LARc (MVA): Security standard load at risk for single contingent conditions.
LARc (MW): Estimated generation / load reduction required to defer the forecast system limitation. This is the security standard load at risk under single contingency condition, expressed in MW.
Substation Category: For security standard application, the general type of customer a substation or feeder supplying the area.

For further information, please refer to Appendix D of Ergon Distribution Annual Planning Report.

The Transmission Connection Point Forecasts include the following information for 50 PoE and 10 PoE in summer and winter:

• Ergon Energy region
• TNI: National Electricity Market - Transmission Node Identity
• TCP Name: Name of the Transmission Connection Point
• Forecast Peak Load (MW)
• Forecast Peak Load (MVARu) (VARu = Volt Amps Reactive Uncompensated, i.e. with stated compensation not active)
• Forecast Compensation (MVAR)

Exclusions
Forecast capacity is not given this spreadsheet. In the majority of cases, the capacity at the TCP is controlled by the Transmission Network Service Provider, and hence reported by them. In the relatively few cases where Ergon Energy asset boundary at the TCP is inclusive of power transformers, the substation capacity will appear in the Zone or Bulk Supply Substations Forecasts tables. The forecast loads are given exclusive of any connected embedded generation.

The Distribution Feeder Limitations tables include the following information for each constrained distribution feeder:

• Ergon Energy region
• Distribution feeder name, ID & location
• Load exceedance after 2 yrs (MVA)
• Forecast season that exceedance occurs (Summer / Winter)
• Forecast year that exceedance occurs
• Forecast month/s that exceedance occurs
• Load reduction needed to delay the exceedance by 12 months (MW) (assumed power factor of 0.9)

Solutions
Suggested solutions, in order or preference, are included under the 'Solutions' tab.

Connection points for possible load reduction
In all cases, the connection point to apply load reduction would be downsteam of the substation exit feeder cable and/or first section of line.

Exclusions
Dedicated customer connection assets are excluded from the analysis.