Australian steelmaker InfraBuild has upgraded the electrical protection system at its Laverton steelworks in Victoria with the installation of two ABB VD4-AF vacuum circuit breakers to provide backup for its main electric arc furnace (EAF).
The new circuit breakers, supplied by ABB, replace ageing spring-actuated equipment that had reached the end of its service life and posed increasing reliability risks due to limited spare parts availability. Power reliability is critical at the Laverton melt shop, which operates six days a week and relies on frequent furnace start-stop cycles during steel production.
Before proceeding with the upgrade, InfraBuild assessed the performance of the VD4-AF technology, which uses a servomotor actuation system rather than traditional mechanical linkages. The steelmaker consulted existing users of the ABB technology to verify its operational reliability before placing the order.
The VD4-AF circuit breakers were installed as part of an air-insulated UniGear ZS3.2 switchgear panel, designed to fit within the footprint of the original equipment. The system is rated at 2,500 amps, compared with 2,000 amps for the previous breakers, allowing for potential increases in furnace power input in the future.
According to ABB, the VD4-AF circuit breaker is engineered specifically for steel furnace applications and can perform up to 150,000 mechanical operations without refurbishment. The design allows for roll-in and roll-out replacement, reducing downtime during maintenance and lowering lifecycle operating costs.
InfraBuild produces long steel products such as rebar, merchant bar and rod using scrap-based electric arc furnace technology. At the Laverton plant, scrap is melted and processed in cycles of around 40 minutes, requiring dependable interruption and restoration of power on either side of the melting process.
The circuit breaker upgrade, completed in early 2022, forms part of broader electrical infrastructure investments at the site, including medium-voltage transformer upgrades and the installation of a new EAF. The higher current rating of the new system also supports future productivity improvements by enabling shorter melt cycles if higher furnace power is required.
