7 OVERVIEW OF NETWORK LIMITATIONS
7.1 Energex Network Limitations – Adequacy and Security
For each substation, a separate summary, forecast, capacity and limitations report has been produced for summer and winter based on Customer Outcome Standard. Bulk supply and zone substation reports are contained in Volume 2 Section 4.3 and Volume 2 Section 4.4, respectively.
Table 11 shows the projection of bulk supply and zone substation statistics to 2018/19. It also provides the forecast number of bulk and zone substations with load at risk (LAR) under system normal conditions (LARn) and contingency conditions (LARc).
Under system normal conditions, there are no bulk or zone substations forecast to have LAR based on the expected completion of current projects. This is not expected to change over the next five years. Under contingency conditions, there is no bulk supply substation forecast with LAR in 2014/15 to 2018/19 based on the current committed projects being completed.
Under contingency conditions the forecast for zone substations with LAR in 2014/15 is three and increases to four in 2017/18.
Table 11 – Summary of Substation Limitations Identified
Substation Type Substation
1 Assessment based on 10PoE forecasts and Customer Outcome Standard.
2 Assessment based on 50PoE forecasts and Customer Outcome Standard.
3 The zone substations total count includes dedicated customer substations. Customer substation details are not included in Volume 2.
Note: This table includes approved projects only. Proposed strategies to manage the limitations identified are contained in Volume 2 Section 6.
The substation limitations identified are also reported in the limitations tables contained in Volume 2 Section 6. These tables also contain the approved or proposed strategy to manage the identified limitations, along with other related information.
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Maps of Energex’s network showing the location of all Energex’s bulk supply and zone substations are contained in Volume 2 Section 3.1. These maps highlight which substations have limitations that have been identified through the process outlined in Section 6.4.2.
7.1.2 Transmission Feeder Limitations
For each 132 kV and 110 kV feeder, a separate summary, forecast, capacity and limitations report has been produced for summer and winter based on Customer Outcome Standard.
These reports are contained in Volume 2 Section 5.3.
Feeder limitations are identified using the simulation models and processes as described in Section 5.3.2 and Section 6.4.3. The analysis provides load at risk information under normal and contingency conditions and evaluates whether the transmission feeder meets its allocated security of supply standard. The outcome of this analysis would then potentially trigger the creation of new strategic projects which indirectly may or may not trigger an update of the forecast and re-run of the models.
The outlook for the 132 kV and 110 kV feeders over the next five years is summarised in Table 12. With no feeders currently exposed to Load at Risk under normal conditions (LARn), it is not anticipated that this figure will change. Under contingency conditions there is one feeder forecast to have LARc in 2014/15 and 2015/16.
Table 12 – Summary of 132 kV and 110 kV Transmission Limitations Identified System
Note: This table includes approved projects only. Proposed strategies to manage the limitations identified are contained in Volume 2 Section 6.
The limitations identified in the 132 kV and 110 kV sub-transmission feeders are also reported in the Limitations Tables contained in Volume 2 Section 6. These tables outline the approved or proposed strategy to manage the emerging limitations, along with other related information.
Maps of Energex’s network showing the location of all Energex’s bulk supply and zone substations are contained in Volume 2 Section 3.1. The existing transmission feeders are also shown on these maps. These maps highlight which transmission feeders have limitations that have been identified through the process outlined in Section 5.3.2 and Section 6.4.3.
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7.1.3 Sub-transmission Feeder Limitations
For each 33 kV feeder, a separate summary, forecast, capacity and limitations report has been produced for summer and winter based on Customer Outcome Standard. These reports are contained in Volume 2 Section 5.4.
Feeder limitations are identified using the simulation models and processes as described in Section 5.3.3 and Section 6.4.4. The analysis provides load at risk information under normal and contingency conditions and evaluates whether the sub-transmission feeder meets its allocated security of supply standard. The outcome of this analysis would then potentially trigger the creation of new strategic projects which indirectly may or may not trigger an update of the forecast and re-run of the models. There is forecast LAR on 1 feeder under normal conditions in 2014/15, and an operational strategy is available and can be applied to mitigate this risk when required. Under contingency conditions the forecast number of feeders with LAR in 2014/15 is 12, increasing to 14 in 2018/19. The increase in the number of feeders with LAR in 2016/17 is due to a temporary block load connection.
Table 13 – Summary of 33 kV Sub-transmission Limitations Identified System
Note: This table includes approved projects only. Proposed strategies to manage the limitations identified are contained in Volume 2 Section 6.
The limitations identified in the 33 kV sub-transmission feeders are also reported in the Limitations Tables contained in Volume 2 Section 6. These tables also contain the approved or proposed strategy to manage the emerging limitations, along with other related information.
Maps of Energex’s network showing the location of all Energex’s bulk supply and zone substations are contained in Volume 2 Section 3.1. The existing sub-transmission feeders are also shown in these maps. These maps highlight which of these sub-transmission feeders have limitations that have been identified through the process outlined in Section 6.4.4.
7.1.4 11 kV Distribution Feeders Exceeding Target Maximum Utilisation
Results of the analysis of 11 kV feeder load, capacity and utilisation forecasts for five years are contained in Volume 2 Section 5.5.Table 14 below provides a summary of the results of all the 11 kV feeder limitation analysis for 2014/15 and 2015/16:
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Table 14 – Summary of 11 kV Feeders > TMU Identified
11 kV Feeder Condition 2014 / 15 2015 / 16 Detailed Results Feeders with forecast
TMU limitation
15 22 Volume 2 Section 5.5
Total Number of Feeders 2061 2085
Note: Total Number of Feeders excludes dedicated customer connection assets.
Maps of Energex’s network showing the location of all Energex’s bulk supply and zone substations are contained in Volume 2 Section 3.1. For zone substations that have one or more 11 kV feeders identified as having a forecast exceeding TMU, the number of feeders is indicated on those maps. For each of those 11 kV feeders identified, a separate map showing the area it supplies, or further information where map details are not available, is contained in Volume 2 Section 3.2.