South West Network Communications Replacement
AusNet Services is undertaking this Regulatory Investment Test for Transmission (RIT-T) to evaluate options for maintaining communication reliability in the South Western Victorian Transmission network.
Publication of this Project Specification Consultation Report (PSCR) represents the first step in the RIT-T process in accordance with clause 5.16 of the National Electricity Rules (NER) and section 4.2 of the RIT-T Application Guidelines. AusNet Services is also exploring opportunities to accelerate the RIT-T process for this project as allowed by NER clause 5.16.4(z1).
The protection, control, Supervisory Control and Data Acquisition (SCADA) and operational communications for the South Western Victoria Transmission network and interconnection to South Australia is currently enabled by communication assets known as SDH/PDH (Synchronous Digital Hierarchy / Plesiochronous Digital Hierarchy) and 5-hop microwaves. The SDH/PDH asset currently serves the following lines within the Victorian Electricity Transmission Grid in the South Western Region:
- 220kV lines from Moorabool to Terang
- 220kV lines from Ballarat to Terang
- 500kV lines from Moorabool to Heywood
- 500kV lines from Heywood to Portland Alcoa APD
The condition of the existing SDH/PDH technology has deteriorated to a level where there is a material risk of asset failure. Asset failure could reduce electricity transmission reliability, impact safety, the environment, and require potential costs for emergency replacements. SDH/PDH technology has served the business for over 35 years and is now considered a legacy technology. Additionally, the current SDH/PDH and 5-hop microwave communication loop cannot support the future Victorian Renewable Energy Zone (REZ) Development Plan, as it lacks the bandwidth required.
The PSCR identifies the following credible network solutions that could meet the identified need:
- Option 1 – Replace SDH/PDH and radio with MPLS-TP and fibre cable; or
- Option 2 – Replace SDH/PDH with MPLS-TP and upgrade radio
AusNet Services does not consider that any non-network options would be able to address the identified need.
AusNet Services’ cost-benefit assessment identifies Option 1 as the preferred option. This option will not only maintain transmission reliability, but also allows for ease of maintenance and provides sufficient bandwidth to accommodate the implementation of the REZ. The optimal timing of the preferred option is 2025/26 and is expected to have a total nominal cost of $22.8 million.
Submissions should be emailed to rittconsultations@ausnetservices.com.au by 18 August 2022. In accordance with the requirements of the National Electricity Rules, a summary of the PSCR is made available on the AEMO website. A copy of the PSCR can be obtained from AusNet Services’ website.