Palmerston to George Town OPGW
The Palmerston – Hadspen - George Town OPGW Installation project involved the upgrade 85 kms of existing 220kV transmission line infrastructure between Palmerston and George Town in Tasmania. The project extended over 100 road crossings, eight major highway crossings, four rail line crossings and eight river crossings including the Tamar River alongside the Batman Bridge. Works were also carried out over the Cataract Gorge, Batman Bridge and through the Trevallyn Nature Reserve.
The project scope included tower strengthening (installation of new steel), assembly and helicopter installation of new earth peaks and stringing new Optical Ground Wire (OPGW). The 85km line included 243 tower structures and three substations. Most works were conducted under live conditions with only a select few stringing pulls conducted under outage conditions.
Over the project duration, there were a variety of project management and engineering challenges. But amidst these obstacles, and truly a credit to all project partners, the team delivered impressive results on safety, environment, quality and stakeholder relations, as well as early project completion three months earlier than the program schedule.
The key to the project’s success was that all works were self-delivered through the collaborative efforts of all involved, despite extreme wet weather hampering the construction effort. Timely delivery was a major factor given a nominated 12 month program with minimal permissible outages to complete some of the works as dictated by hydro power generation demands and critical continuity of supply.
The project demonstrated outstanding collaboration cross the supply chain to pioneer methodologies and overcome the challenges of installing the OPGW under live conditions and with challenging topography.
Collaboration also saw the development of a number of innovations including a bespoke tower foundation upgrade solution and a new method of stringing towers. The first innovation “overlay type” tower foundation provided a much more aesthetic solution than traditional concrete structures, and was more appealing to landowners. This solution precluded the need for large concrete structures or reinforced structures below ground and therefore also provided a more sustainable option.
The new method for stringing towers allowed the high voltage power rope to be pulled through the centre of the tower, reducing the need of double handling, resulting in a safer and more efficient end product. This initiative resulted in significant immediate cost reductions for Transend and has now been adopted for future use on transmission lines throughout Tasmania.