Zinfra contracted for 22kV rebuild and transformer replacement

Infrastructure services company Zinfra has been contracted to deliver a complex $9.2 million brownfield project for client SP AusNet at the Ringwood Terminal Station in Victoria.

The core works involve replacing three sets of single phase 220/22kV transformers, each rated at 45MVA. The old transformers need to be decommissioned and dismantled and their footings removed. In their place will be two new three-phase 75MVA transformers.

In order to make space for the new transformers, the existing 22kV yard requires major civil work, including the undergrounding of four exit feeders and installation of a new switch room, utilising state-of-the art GIS.

Construction of a new 220kV bay is also required to provide supply to the first of the new transformers, which must be put into service prior to removal of any existing equipment.

The Ringwood substation services a large, highly populated area in the south-east of metropolitan Melbourne, extending from Croydon to Frankston. A major challenge for the project is ensuring continuous power supply to this large customer base during the changeover, conforming to the client stipulated N-1 contingency.

Cutover of protection and control has also been a major consideration for Zinfra’s Commissioning Engineers, as the existing secondary systems must be interfaced with the new equipment.

The project is scheduled for completion in September this year.