Surrey lab produces high voltages to simulate lightning
Grounded in reality, testing is about safety and reliability of electricity system
At the largest high-voltage testing lab on the west coast of North America, no one pretends that tests designed to simulate the effects of a lightning strike on power lines are quite like the real thing.
"Lightning voltages are way higher than what we can generate – lightning surges can be 100,000 amps - huge current, huge energy," says John Vandermaar, director of high-voltage testing at Surrey's Powertech Labs. "If lightning directly hits a tower, it's going to fail. It can't withstand it. It's not designed to withstand a direct strike."
But that doesn't mean you can't protect the electrical system from the damaging effects of lightning strikes or other impulse voltages with the potential to send a wave of destruction through power lines. Like other electrical utilities, BC Hydro relies heavily on protective equipment on systems, including lightning arrestors that prevent damage to the grid and to equipment in customers' homes and businesses.
And there's no better way to test equipment - from transformers, to insulators, to cables and even to the bucket trucks our power line technicians work from - than with the high-voltage equipment at Powertech, a subsidiary of BC Hydro.
'10,000 times higher than the voltage coming out of your wall plug'
Standing in a cavernous room that's more akin to an aircraft hangar than to a science lab is an assortment of equipment that, depending on your perspective, could be supersized playground equipment or a supervillain's weapon. The lab is impressive enough to have starred in the likes of The X-Files and Stargate SG-1 over the years, and its capacity for destruction – at least of electrical components – is very real.
"In your house, the plug in the wall is 120 volts, and your clothes dryer, your stove, uses 240 volts," says Vandermaar. "In here, these three stacks can go up to 1.2 million volts. So we're 10,000 times higher in voltage than is coming out of your wall plug. And our impulse generator is good for 3.2 million volts."
Given that the highest voltage in BC Hydro's system is 500 kilovolts – or 500,000 volts – why would you use testing equipment that's capable of combining to produce millions of volts? The idea is to take the equipment beyond its regular limits, in part because you want equipment to keep working even after it degrades over time, but also because of those nasty lightning strikes.
"The equipment has to be designed so that it doesn't blow up when a lightning strike comes along," says Vandermaar, who works in the lab alongside Dr. May Wang, one of 27 Ph.D's at Powertech. "The switches in our system, circuit breakers, are like the light switches in your house, where you turn the power off. But this is a giant switch, with far more current. If it doesn't work properly, it literally will explode."
Those million-plus volts come in handy, but the vast majority of testing in the lab is done at voltages closer to what's used in BC Hydro's transmission and distribution system. These are still very dangerous voltages, and the wide variety of tested equipment includes bucket trucks - which need to be re-certified every three years – that you see our crews working from when repairing power lines.
CSI: Surrey... what's to blame when something goes wrong?
Powertech Labs also provides a forensics role, using the high voltage lab to assess equipment to determine the source of any failure in the system. Transformers have been tested, failed insulators are tested regularly, and when something really big fails – such as at substation at one of our generating stations – the testing goes mobile.
Each piece of those tall impulse voltage testers, the towers that include orange and blue (or the newer blue and white) barrel-like units, can be detached and put on a transport trailer. These parts are shipped, then reassembled for on-site testing, as far away as the Mica Generating Station north of Revelstoke.
"We test equipment at significantly higher voltage than it operates at in the field to make sure that there's some safety factor there," says Vandermaar. "Equipment, over time, deteriorates. So just because it could withstand 800 kV when it was new doesn't mean that it can withstand it 10 years from now, 20 years from now. We want to make sure it will continue to work long-term at those voltages."
The process of assembling those impulse generators has a special place in Vandermaar's heart. It was as a young engineer out of Manitoba, looking for a steady job with BC Hydro more than three decades ago, that he first arrived at Powertech to reassemble a resonant test set and – his hands covered in aluminum oxide from the rings – he first shook the hand of Laurie Snider, who would become his department boss.
Vandermaar would go on to become a high-voltage expert, not bad for a guy who preferred electronics at the University of Manitoba and passed on the power courses offered there.
"You get very nonchalant about what goes on here, thinking 'it's only 100,000 volts'," he says with a laugh. "But when people bring it up, you're reminded this is actually huge. It is like science fiction in some ways. It's pretty cool."