The smell of fried squirrel lingered in the air.
An hour earlier, the frolicking rodent triggered a fireball atop a substation that damaged electrical equipment and shut down power to the southern Yukon for an hour on Thursday morning.
About 2,400 amps of electricity flowed through the animal, cooking it at about 3,000 degrees Celsius, said Jay Massie, superintendent of operations at Yukon Electrical Co. Ltd.
Its charred remains were found lying on the snow beneath a breaker.
“I wouldn’t want to be here when it happened,” said Massie, “You wouldn’t have felt a jolt but you would have felt the heat coming from it.”
The carcass was quickly removed from the substation.
“We got to get him out of here because the ravens will be here next,” said one Yukon Electrical employee at the site.
The Mountainview substation, tucked in the woods on the northern side of Mountainview Drive, has a high gate and barbed wire to keep animals out. But spring brings heightened animal activity
“We call (this time of the year) the running of the squirrels,” said Massie.
The animal breached the fence and climbed onto one of the substation’s three breakers. They manage power downstream from the power station.
The squirrel latched onto two of the six insulators on top of the breakers.
These insulators—which are meant to contain the electrical current and keep it flowing—usually carry around 60 amps.
But when the squirrel made its move, it caused a fault sending massive amounts of electric current into the air around the breaker.
The instantaneous ionization of the air caused a fireball, which burned the porcelain insulators and caused roughly $10,000 in damage, said Massie.
As that electrical current jumps from 70 to 2400 amps, the breaker begins asking for more power from the grid’s power stations, managed by the Yukon Energy Corporation.
When a substation demands that much energy that fast, it ends up cutting power on the remaining grid.
“It was too big of a loss for the entire system to catch and it just cascaded after that,” said Massie. “Once (Yukon Energy) loses a big chunk of load, it’s very difficult for them to hold on to the rest of the system.”
Lights went out across the Whitehorse-Aishihik-Faro grid just before 9 a.m., and was returned in stages over the course of an hour, said Massie.
Yukon Electrical and the Yukon Energy Corporation use technology, called SCADA, to try and contain faults and other electrical disturbances, but it always depends on the power of the fault.
“One of the problems with this is that hydro is slow,” said Massie. “So when a fault causes a fireball like this, it increases the load, but it’s water spinning in turbines so itcan’t react as fast as down south where they have steam, coal and nuclear power that’s just instantaneous.”
“It’s just one of the issues with a hydro system.”
The companies have considered upgrading the system, allowing computers set at breakers to relay information to the control centre more quickly, but it’s a question of balancing an expensive investment against an acceptable degree of outage risk.
However the technology is getting better and cheaper because of breakthroughs in communications technology, said Massie.
Contact James Munson at