Ampcontrol was awarded the contract for the comprehensive refurbishment and installation of multiple power transformers at Snowy Hydro’s Tumut 3 Power Station.
Problem
Several transformers required overhaul, upgrades, and reinstatement without compromising safety, environmental controls, or station availability.
Works needed to be executed within 10 day outage windows and coordinated around operational constraints, including periods of limited site access (such as the Christmas shutdown). The project also required controlled oil handling and conditioning, rail movement of transformers within the facility, and rigorous verification before return to service.
SOLUTION
Ampcontrol delivered a staged transformer refurbishment program for 4x 176MVA transformers, aligned to Snowy Hydro’s planned outage schedule, with each change-out managed within an approximate 10-day window, with a clear focus on safety, quality and turnaround efficiency.
The approach combined upfront engineering controls (SWMS, execution plans, ITP/ITR, environmental and oil management plans) with coordinated site logistics, specialist subcontractor management, and assembly bay works to reduce execution risk and maintain program momentum across sequential outages.
The spare transformer was overhauled first over an approximately 4 week period. This transformer was then substituted into an active bay during a changeout to take the position of the next transformer to be overhauled in the assembly bay, to maintain the 10-day outage windows and maximise the station's availability.
On site, Ampcontrol managed transformer isolation, oil draining and sampling, rail relocation, refurbishment, reinstallation and commissioning as one integrated process.
Refurbishment works included:
- Inspection and repair
- HV bushing and connection upgrades
- Heat exchanger and pump refurbishment/replacement
- HV CT and instrumentation replacement
- Leak repairs
- Gasket/seal replacement
- Auxiliary and protection upgrades
- Oil filtration/conditioning (including vacuum/degassing)
- Electrical and insulation testing.
OUTCOME
Ampcontrol delivered a low-risk, high-quality refurbishment program that enabled Snowy Hydro to complete critical transformer works within planned outage windows while maintaining operational readiness. Each transformer was then returned to service with full testing, reporting and certification to support Snowy Hydro’s asset management requirements.
The staged delivery approach, supported by detailed planning and on-site engineering expertise, helped minimise execution risk across transformer removal, overhaul, re-installation and commissioning.
By refurbishing rather than replacing the assets, Snowy Hydro gained extended transformer service life, improved reliability and reduced future maintenance costs. Comprehensive testing, reporting and certification provided confidence in asset performance and supported ongoing lifecycle and compliance management, while regular communication and responsive project management helped build trust and confidence throughout delivery.
