Moving mountains to keep the power flowing

Replacing two transformers on Queensland’s second highest mountain while ensuring minimal interruption to the electricity supply is no mean feat, but Zinfra overcame several challenges to get the job done, using its significant experience in the power sector to gain practical completion on the project three months ahead of schedule.

Earlier this year, Zinfra was engaged to replace two transformers and a degraded 22kv cable for Broadcast Australia at its Mt Bellenden Ker site in Queensland.

Broadcast Australia, a BAI Communications company, own and operate one of the world’s most extensive transmission networks. Their tower at the summit of Mount Bellenden-Ker in far north Queensland is one of the most difficult environments in which they operate given its location at the top of a mountain within a World Heritage Park, surrounded by rainforest that is subject to 8mm of rain annually.

Zinfra gained possession of the site on Monday 16 July 2018, and full energisation of the substation was completed on Thursday 23 August.

The scope of work for this project included decommissioning and removal of the two existing 22/0.4kV power transformers and 22kV cables, as well as the design, supply and installation of new 22kV cables, two new 22/0.4kV power transformers and a permanent earth switch cabinet arrangement. Works also included testing and commissioning of the final substation installation, as well as energisation and post energisation checks and tests.

One of the main challenges that Zinfra faced was reducing the duration of the power outage.

"Originally the outage was scheduled for more than two months, however by rescheduling a number of activities to run in parallel, as well as mobilising additional resources, we were able to shrink it to thirty days," Zinfra Project Manager, Douraid Farid, said.

"We also committed to Broadcast Australia that whenever they needed the substation returned to power, even if we were in the middle of an outage with transformers scattered around, we would restore the power in under two hours."

Exceptional performance highlighted in a testing environment

Mt Bellenden Ker is the second highest mountain in Queensland and access to the project site was only available via a private cable car, with the journey taking approximately thirty minutes.

"In order to lift the materials, machines, plant and equipment, we had to use a combination of heavy and light lift choppers," Mr Farid said.

"The climate in that area is tropical so the weather was also a huge challenge. We couldn’t deploy a chopper, or any type of helicopter, in inclement weather conditions, but if the chopper had already been prepared for us, we still had to pay the bill.

"When the weather was good, it was imperative that we made the most of it which would sometimes necessitate working weekdays and weekends. Because we were working around the clock we organised two crews to support each other during this time and to minimise the risk of fatigue.

The project site was situated within the West Tropics Management Authority and Wooroonooran National Park, making it environmentally sensitive, requiring rigorous planning and lengthy approval processes.

Zinfra effectively navigated the environmental challenges, producing high quality work, in addition to completing the works almost three months ahead of schedule.

HSEQ data audits were carried out in July, with Zinfra achieving a high level of compliance and the project attaining an overall safety score of 96 per cent, against a target of 95.

Mr Farid said that Broadcast Australia are very happy with Zinfra’s performance,

"The job was critical to the client and we tackled their fears. Everyone is calling the project a success."