Richard Gleeson
Northern News Services

NNSL (Dec 18/98) - You can turn those Christmas lights back on.

After a cold and frantic night and day for the NWT Power Corporation, the city's power supply is back to normal.

"We're declaring everything back to normal and we're confident it will stay that way," said NWT Power spokesperson Bill Braden at about 2:30 p.m. Thursday.

The announcement brought to an end 22 hours of the city operating on a paper-thin margin for error.

Frost buildup caused a failure late Wednesday afternoon of the 140 kilometre line connecting the city with NWT Powers Snare Hydro system.

The weight of frost, six inches (15 cm) thick on some parts of the line, caused the lightning-protection cable that runs between the tops of the hydro towers to sag and touch the power cables below it, shorting out the system.

"We haven't seen these kind of frost conditions since the transmission line was built in 1989," stated regional director Dan Roberts in a news release issued by the corporation Wednesday.

Roberts said the line had been inspected just six days prior to the outage.

Crews left Yellowknife by helicopter Thursday morning at 9:45 p.m. to inspect the lines. Roberts said the worst section spanned a hilly area 120 kilometres north of the city.

"Knocking off the frost took about an hour," said Roberts. "We were done by noon."

Damaged wire also had to be repaired.

Frost buildup also caused an outage two weeks ago. To prevent a similar occurrence, the eight kilometres of lightning-protection cable was removed at an estimated cost of $80,000.

"It looks like we'll have to take out another 12 kilometres," said Roberts. "In the meantime we'll be doing regular line patrols. If the weather turns cold we should be okay."

While the line damage was being repaired, the city was operating on diesel power from the Jackfish plant, supplemented by a small amount of power from the Bluefish hydro station on Prosperous Lake.

"The diesel plant, when all 13 engines are running, has a maximum capacity of 33 megawatts," said Braden.

"Right now two engines are down with mechanical problems, which limits our capacity to 28 megawatts."

That is also the amount of power the city draws during peak periods. The Bluefish plant supplies six megawatts.

The corporation thanked several of its larger customers, especially Giant Mine, for taking conservation measures during the power pinch.