Stockdill Substation and Transmission Line

To ensure the safe and reliable supply of electricity to the ACT, and support the future growth of the region, TransGrid has undertaken a joint project with the ACT Government and EVO Energy called the ACT Second Electrical Supply Project.

The ACT ’s Electricity Transmission Supply Code reliability criteria requires TransGrid and EVO Energy to provide a secure electricity supply to the ACT through the provision of geographically separate and electrically independent 132 kV above supplies and alternative connection points to allow an ongoing electricity supply. TransGrid currently supplies the ACT load via their Canberra substations.

As part of the requirement for a second, fully independent supply point, TransGrid engaged Zinfra to construct a 330/132 kV substation and associated 330 kV transmission line works. Works are being delivered in three Separable Portions:

1. Separable Portion 1 - 330kV Transmission Line Connections

2. Separable Portion 2 - Stockdill 330/132kV Substation Construction

3. Separable Portion 3 - Canberra No.2 & No.3 Transformer Decommissioning & Disposal

Works include:

• Construction of 330/132 kV transmission lines including: Construction and operation of a 6km 330 kV transmission line between the proposed Stockdill Substation and the existing Canberra substation.

  • Diversion using a newly built section of approximately 850 metres of 330kV line to divert existing lines into the newly built Substation.

  • Removal of decommissioned sections of transmission lines, existing line towers, conductors and associated foundations and other wiring.

• Construction of the 330/132 kV Stockdill Substation, which includes: Approximately 250 individual concrete footings and steelwork supports

  • 27,000cu.m of excavation and earthworks

  • Access Roads

  • Installation of high voltage plant

  • Supply and Installation of a control building

  • Cable pathways, cable installation

  • Pre-commissioning and commissioning

• Decommissioning and removal of existing transformers no. 2 and no. 3 from Canberra Substation.

  • Line rearrangements, bypasses and connection of new transmission line to the existing Canberra Substation.

  • Installation of optical ground wire (OPGW) for the new sections of proposed transmission line.

  • Vegetation clearing and earthworks for the above works, suitable for a 330 kV transmission line easement width of up to approximately 60 metres.

TransGrid’s new 330/132kV Stockdill Substation will provide the ACT with a second supply point, and one that is independent of Canberra 330/132kV Substation.