This project involved the removal of two old 30 MVA oil insulated transformers and the installation of two new 39MVA GIS (SF6) TOSHIBA transformers at the Barron Gorge Hydro Power Station, just north of Cairns. The work proceeded and was completed ahead of schedule considering the work was undertaken in very cramped conditions with many disruptions due to other contractors involved in the refurbishment of the power station requiring to pass through the work area.
After the fences and bund walls were removed, the two transformers and radiator banks were drained consecutively of oil into specially bunded road tankers. This followed very strict environmental guidelines and procedures mitigating any concern of possible oil spills as the location of the power station is within a Heritage National Park.
All the radiators, pipe work and other ancillary equipment from both transformers were dismantled and transported off site. The old tanks were removed by heavy lift contractors. The foundations for the new transformers were prepared. A large blast wall was removed to allow room for the larger sized new transformers. The new transformer tanks were installed onto their prepared pads.
Simultaneously the new fans and radiators were erected and installed on both the new transformers. The interconnecting pipe work installed, the HV and LV bushings installed and internal HV connections made. All external cabling was installed and connected and tested. The transformers and radiators were subjected to a predetermined vacuum period and leak test before the transformer tanks and radiators were filled with SF6 gas. The transformers were tested, the fences and signage installed and the area thoroughly cleaned before the disestablishment of the site.
The client signed the work completion off at the conclusion of the site works with the absence of any “punch list” and no follow-up work has been required to be undertaken from the construction period up until both GIS transformers were successful commissioned and nothing thereafter to date.