Bringing down the lines

29 October 2012

A subtle, but significant change, to the sky scape in east Auckland is underway with the dismantling of the last sections of the 110 kV Pakuranga to Penrose A transmission line and towers.

The work is part of Transpower’s North Auckland and Northland grid upgrade project and the line is being replaced with a higher voltage 220 kV underground cable between Pakuranga and Albany.pak-pen-dismantling.jpg

Project Manager Stephen McAdams says working in an urban environment is challenging, particularly as the line passes over major road crossings, built up residential areas and many towers are located on private property.

“It’s not just a simple matter of dismantling and lowering the line it to the ground. We need to take full account that we are working directly above people’s homes and what the consequences would be if the line was to fall.”

To prevent such an occurrence and to maintain tension on the line during removal, cranes and winches are used to pull the individual line spans through blocks to one end where they are reeled on a drum for ease of transport.

Up to a dozen workers are involved in the process including a community liaison manager who keeps directly-affected people informed of what is happening and how they may be affected.

The removal of the line has been done in stages, with the first section between Transpower’s Penrose substation and the Tamaki River coming down earlier this year.

Originally suspended from 35 transmission towers and spanning over 10 kilometres between Transpower’s Pakuranga and Penrose substations, the Pakuranga to Penrose A line has held its place on the skyline for over 70 years.