The SUPP has been designed to replace overhead mains with a safer, more reliable underground system. Property owners benefit greatly from an underground power supply for many reasons including greater security of supply, less chance of damage to mains, more attractive streetscapes, thus increasing property value, and reduced interference from trees and flora.
Since the program commenced in 1996, 32 major residential projects have been completed with approximately 60,000 properties being converted to underground power at a cost of
$A200 million. Twenty-nine local enhancement projects have also been completed, resulting in 19 kilometres of overhead lines laid underground.
The Government has promised that half of the Perth metropolitan area would be serviced by underground power by 2010. To accommodate this, the program was split into two components: a major residential projects arm, and one that catered for smaller, localised enhancement projects. New property developments have also been built with underground electricity supply only.
The program is now in its fourth round, with four major underground residential projects in the metropolitan areas and two localised enhancement projects in regional areas.
HDD: a cost effective solution
Underground Services Australia (USA) has assisted Western Power with SUPP projects across several councils since 1996, including the areas of Cottesloe, Wembley, Peppermint Grove, Dalkeith, Como, South Perth, City Beach, Nedlands, Fremantle, Wembley and Rockingham. During this time, USA Managing Director Peter Rowles estimates the company has laid approximately 500,000 metres of electrical cable using directional drilling.
Mr Rowles says that using HDD is a far safer and more cost effective solution compared with open trenching.
“Causing damage to existing underground assets reduces productivity. It’s costly and gives your company a bad reputation. Professional clients such as Western Power no longer accept excuses when it comes to damaging existing utilities, and now require you to put sustainable rigid systems in place to eliminate damage to underground assets.”
The company has ten drill teams, and prides itself on “its ability to train and grow internally to produce experienced personnel”. USA has two full time Vermeer location vehicles, which are both equipped with a ground probing radar, radio frequency electronic locators and a vacuum excavation unit.
Overcoming challenges
Mr Rowles says the company has faced several challenges in its work for the SUPP, such as the changing ground conditions, which vary from project to project.
“We recently completed the Palm Beach project that involved in excess of
25,000 metres of drilling in consistent white beach sand, but prior to that we completed the Wembley project that consisted of some 75,000 metres of drilling in a blend of yellow sand, pinnacles of limestone and sections of solid limestone and cap stone.
“Each project has its challenge and in the case of the Wembley project, the changing ground conditions were challenging to say the least.”
Another major challenge has been to keep the many thousands of residents happy while construction is in progress.
“No-one is happy to have construction workers working in front of their house. No matter what method you use, there is always someone’s front yard that requires a hole or two, and they want to know why the hole was in front of their house.
“Can you imagine digging up everyone’s front yard for weeks on end? You can imagine the complaints and issues. We think it’s hard with a few holes.”
The evolution of the HDD industry
Over time, Mr Rowles has noticed that the use of directional drilling for installing underground pipes and cables has become more prominent as a viable alternative to trenching.
“Western Power’s SUPP was the first that I know of in Australia to take up directional drilling seriously for the installation of underground power and since then, the market has grown year on year.”
He recalls a conversation that highlights just how much the HDD industry has grown.
“I was talking with someone the other day and he said it’s now unusual to see someone excavating a trench along the verge to install a pipe or cable. Years ago, it was the norm.
“Now, if you see someone excavating, you think, “÷I wonder why they are not drilling it.’ Directional drilling has been a significant change in how we go about installing underground utilities.”