Pole program an example of asset management

N.L. Hydro relies on planning and regular testing for system reliability

Published on September 30, 2012
Nalcor Energy power line technician Jim Hoskins exits the Western Avalon substation at Chapel Arm. Power from the Bay D'Espoir hydro plant will come through here on the way to St. John's and all of it reliant on the utility poles staying up. Photo by Ashley Fitzpatrick/The Telegram

Newfoundland and Labrador Hydro's proposed capital project spending for 2013 is under review by the Public Utilities Board (PUB). Much of the $66 million in planned work centres on asset management.

That includes maintenance on infrastructure - to keep the hydro plants running at optimum strength and power lines from failing in a storm.

In a boardroom at Hydro Place in St. John's Thursday, Nalcor Energy president and CEO Ed Martin said both the Crown corporation's Churchill Falls division and Newfoundland and Labrador Hydro have 20-year outlooks for capital spending. From this flows 10-year and five-year plans.

"In behind (the documents), is a lot of rigour as to why we've scheduled that kind of work," Martin said.

He explained the focus of the planning is on catching infrastructure problems before they actually become problems.

"Particularly now, with Newfoundland, with the island, being an isolated system, we have to be ahead of the game," he said. "We can't afford to have assets that are unreliable."

On the ground, unit supervisors take five-year plans and break them down into yearly, monthly and daily plans and, as work is completed by utility crews, feed information back on the status of infrastructure and future needs, potentially changing the core planning as it stands.

Getting to know the poles

Driving along the Trans-Canada Highway from St. John's, Terry Gardiner, Newfoundland and Labrador Hydro's manager of transmission and distribution, can tell you the identifying number for any transmission line you spot.

With a quick glance, he can pick out the height of a steel tower. Different tower types are used for turning a power line and there are towers for certain elevations and ice loads, he explains. All of the pieces are considered in the original line's design.

The same goes for wooden poles on smaller distribution lines. On asset management, Gardiner says a prime example of that kind of work is the wood pole line management program.

First launched as a pilot program in 2003, the program is being continued as a means of extending the life of Hydro's utility poles. The poles cover 2,500 kilometres of the transmission system.

The program determines their end-life by an assessment of their condition, rather than replacing a whole line at a given time.

Utility poles are manufactured to specific standards, with a preservative forced into the wood during manufacturing.

"Of course wood, being wood - it's just like your deck," Gardiner said. "You build the deck, you put on your (seal) and, after 10 years, one piece of board is rotten, while the rest of it is best kind. Because it's wood, that's just the way it is. So what we do, is we take core samples to figure out how much treatment is left in that pole."

Obtaining samples and hands-on assessments of anywhere from 2,400 to 2,500 poles a year is left to the "power line technicians," or linesmen, as they are better known.

Poles undergo a number of tests

Standing at the base of a wooden transmission tower near Chapel Arm, under a line carrying power from Bay D'Espoir towards St. John's, linesman Jim Hoskins said insect damage and unseen rot inside are two problems likely to prompt a pole's replacement.

In a spot check from the ground, Hoskins notices a crack along a crossbar. He then proceeds with another test - boring into the base of the pole with a machine that provides a readout, sketching a line along a piece of paper. From the line sketched, linesmen can determine if there are any cavities within the pole.

Hoskins' fellow linesman, Paul Slade, conducts a different bit of work - removing a core sample from the pole in question.

Samples - not as wide as a dime - taken from Hydro's wooden poles are sent to Stella-Jones, a pole producer in Nova Scotia. They are tested to further determine the pole's strength and how much preservative remains inside it.

Slade scrambles up the pole, showing how boron rods are inserted, introducing further preservative at key points.

"Some people, they get a bit nervous. Then you've got a tendency to hold tighter," Slade said with a smile when back on the ground.

The linesmen said steel tower lines can be checked in winter, but wooden poles are safer to inspect before the ice comes.

System holding up well

A recent review of the wood pole management system, submitted to the PUB, notes there have been no outages on Hydro's transmission system on the Avalon Peninsula since 2005.

Meanwhile, it states, the interconnected system across the rest of the island has had an 85 per cent improvement in reliability.

"This excellent performance is attributable to the on-going inspection and preventative treatment program that Hydro has carried out since 2005," it states.

Failures can still happen on any piece of infrastructure. For this reason, "critical spares" are kept in storage at Bishop's Falls and their use carefully tracked.

Without spare parts available and ready to go, some infrastructure would take months to replace should it fail, Gardiner said.