Transmission Line 39 Diversion

  • Why is the project needed?

    The Australian Government has confirmed that Commonwealth-owned land at Badgerys Creek will be the site for the Western Sydney Airport, with construction expected to commence from late 2018.

    A small section of TransGrid’s 330kV high voltage transmission line (known as Line 39) currently crosses the airport site on structures at the location of the first runway. The Australian Government and TransGrid are working together to relocate the transmission line underground, within the boundary of the airport site.

    Works will also include two new transition sites; where the existing off-site overhead transmission line meets the new underground cable. This will ensure the works are achieved with minimal disruption to the surrounding community.

  • What will the project involve?

    ​To enable earthmoving works at the Western Sydney Airport site to commence by late 2018 and for safe and efficient operations to commence in 2026, the following activities are required to be undertaken:

    • Relocation of a 3.2km section of the TransGrid-owned Line 39 (TransGrid’s existing 330kV single circuit transmission line between Sydney West and Bannaby) which transects the airport site and is incompatible with the development of an airport.
    • Replacement of the existing 3.2 km of transmission line with an underground cable - primarily along the perimeter of the airport site but wholly located on Commonwealth-owned land.
    • Build of two new transition towers and switching stations where the existing off-site overhead transmission line meets the proposed underground cable (on existing TransGrid easements).
    • Installation of aerial Optical Ground Wire (OPGW) along the top of the length of the line; across approximately 14km of Line 39 external to the Commonwealth land. The cable performs the conventional task of providing the electrical ground wire of the network whilst the optical fibres within the cable enable suitable communication requirements for control and monitoring of the transmission line. All this work relates to TransGrid’s existing transmission line.
  • What is the work that has been completed to date?

    The Australian Government is undertaking a range of activities towards Western Sydney Airport commencing operations in 2026.  The Environmental Impact Statement has been finalised (excluding the relocation of TransGrid's 330kV line, which will be subject to a separate environmental process) and approval of the Airport Plan, authorising construction and operation of the Stage 1 Western Sydney Airport.

    The Airport Plan provides for the relocation of the existing 330kV transmission line to an alternative underground route as an authorised activity under the Airport Plan.

    TransGrid has completed the following activities:

    • Undertaken investigations into the Transmission Line 39 Diversion Project. Investigations have included desktop and onsite studies as well as consultation with relevant authorities including Airservices Australia, Roads and Maritime Services and other utility and infrastructure providers. Investigations have progressed through a series of stages to ultimately agree on the detailed design and scope to relocate part of Line 39. 
    • Issued a project introduction letter to landowners along TransGrid’s Line 39.
  • Where can I get more information on the Western Sydney Airport Project?

    ​​For more information about the Western Sydney Airport, please visit

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