HVDC converter transformer. (Photo courtesy ABB)
HVDC converter transformer. (Photo courtesy ABB)

Early one Sunday afternoon last September, for reasons that may never be clearly understood, someone fired three or four rounds from a high-powered rifle into the main high-voltage transformer in Garkane Energy Cooperative’s Buckskin Substation, in far southern Utah.

It didn’t take long for thousands of gallons of coolant to spill from the transformer’s punctured radiator fins. Soon after that, the unit’s core began to overheat, and its connections shorted out. And then came the inevitable: Nearly 10,000 homes and businesses, almost 75 percent of the co-op’s accounts, went dark.

At the co-op’s headquarters in Loa, Utah, dispatchers were able to bypass switches and reroute power to bring half of those services back on within an hour and a half. But 5,000 downline accounts, in small communities and isolated homes near two popular national parks and a national monument, went without power for more than seven hours.

While it may not have seemed like it to the Garkane Energy members hoping to watch football that day, the seven-hour outage represented a triumph of resiliency for the co-op. Things could have been so much worse.

‘Mobile Substations’

“Given the hand we were dealt, we performed quite well in getting the power back on,” says Bryant Shakespear, the co-op’s planning engineer.

Luckily, the bullets didn’t penetrate the transformer core. A contractor specializing in transformers was able to refurbish it, and it was back in service within several weeks. If the damage had been more severe and full replacement had been required, the substation and those 5,000 downline meters could have been out of service for months, Shakespear says.

“Some of the distribution-level transformers are pretty standardized,” he says. “But these days, every time you get a substation transformer, you’re talking about a special order, and it takes about a year. New ones are a long time coming.”

That didn’t happen last fall, thanks to prudent preparation and a conscientious Garkane Energy board. The co-op has invested in four mobile substations, consisting primarily of backup transformers of varying voltage capacities, that are kept under lock and key. Stationed on custom-built, heavy-duty semi-trailers, they’re always ready to go.

The co-op’s own tractor-trailer rig, fully fueled and regularly maintained, stands by to pull those transformers to any of the 48 substations scattered across the five counties in two states that comprise Garkane Energy’s 16,000- square-mile territory. There’s also space set aside at those substations to set up and connect a mobile unit when it’s needed.

Co-op managers have also forged the necessary relationships with national park supervisors, federal land managers, law enforcement agencies, and highway department officials to get those temporary transformers down the road and into service fast.

On that Sunday afternoon last September, it took the truck about an hour to make the 30-mile drive to the Buckskin Substation. For several hours more, crews worked around the 6,000 gallons of transformer oil in the pad’s secondary containment structure to change out the connections. Power was restored by that evening.

Shakespear says things might have gone more easily and quickly if Garkane Energy could have strengthened its grid with loop lines to backfeed power as needed to outlying areas of its service territory. But the need for long, low-density runs through rugged, mountainous, heavily forested terrain works against such a plan.

“We’ve looked at it, but the very nature of our system precludes that,” Shakespear says. “This area is not conducive to economically running a looped system.”

So the co-op has done the next best thing by investing heavily in mobile substations as emergency backup for what experts say is the most vulnerable point in the grid nationwide: the high-voltage (HV) transformers that step power down from transmission to distribution levels.

‘A Wake-Up Call’

These critical devices account for fewer than 3 percent of the transformers in U.S. substations, but they carry as much as 70 percent of the nation’s power, according to a 2014 report by the Congressional Research Service (CRS). And they’re subject to the same kinds of dangers—harsh weather, floods and wildfires, earthquakes, even solar flares—that threaten pole-top transformers and other relatively easy-to-replace utility equipment.

But what got the congressional researchers’ attention, along with that of electric utility engineers and managers, industry experts, vendors, and consultants, is a modest but alarming outbreak of gun attacks on substation transformers.

Less than four years before shots were fired at Garkane Energy’s substation, hundreds of rounds had slammed into a Pacific Gas & Electric substation in northern California. Authorities and utility experts called it a sophisticated attack, with bullets striking transformer cooling fins from different angles.

“Because they serve as vital nodes and carry bulk volumes of electricity, HV transformers are critical elements of the nation’s electric power grid,” the CRS report said. “HV transformers are also the most vulnerable to intentional damage from malicious acts. Recent security exercises, together with a 2013 attack on transformers in Metcalf, Calif., have focused congressional interest on the physical security of HV transformers. They have also prompted new grid security initiatives by utilities and federal regulators.”

Along with the lawmakers and regulators, industry vendors have taken an interest too. Among them is ABB, a global utility technology and equipment supplier.

The 2013 attack in California “was like a shock wave in the power industry when it was first reported in The Wall Street Journal,” says Bill Rose, media relations manager for ABB’s power grids division in North America. “There were some discreet discussions going on earlier, but this was a wake-up call.”

Five-Layer Program

In response, ABB worked with electric utilities and the U.S. Department of Energy to come up with the Substation Physical Security and Resiliency Initiative, which lays out a five-step approach to shielding electric transmission and distribution systems against attacks as well as natural threats.

Petter Fiskerud, ABB’s power transformer resiliency program manager, calls the initiative a five-layer program that begins by assessing natural and manmade substation risks and moves on to hardening the facilities’ ability to withstand threats; security monitoring of the assets and their surroundings; arranging for rapid repair of light damage; and developing rapid replacement plans for badly damaged, critical equipment.

Among the methods Fiskerud and ABB recommend for hardening a substation are bullet-resistant metal or brick perimeter walls and adapting new gas-cooling technology to move the entire facility underground or enclose it inside a nondescript building.

“We call them small energy bunkers rather than large energy fortresses,” he says. “With today’s technology, you can actually reduce the size of a substation, which gives you the capability of actually putting it inside a building, which of course is a lot better than putting it outside with a fence around it. If you’re driving around the countryside and you see a barn, you can’t be 100 percent sure that it’s a barn. It might be a substation.”

It’s also possible, Fiskerud says, to bury transmission lines starting a couple miles out from the substation, making it harder for vandals, criminals, or terrorists to follow a corridor right to its most vulnerable node.

ABB has also come out with Asset-Shield, a ballistic protection system built into transformers and other essential, hard-to-repair, and slow-to-replace equipment.

‘A Different World’

This kind of planning and gearing up for catastrophe, Fiskerud says, reflects the changing environment that utility managers and vendors operate in today. In the past, they didn’t spend a lot of time worrying that people would attack substations with guns, endangering the power supply to homes, schools, and hospitals.

“I think it was just a different world before,” Fiskerud says. “Our customers realized how important the transformers were, but we didn’t think in terms of the threat. Now the threat has made it up to the top of the agenda.”

Back in southern Utah, Garkane Energy has come face to face with that threat. The co-op contacted ABB in the aftermath of last fall’s attack on the Buckskin Substation, and CEO Dan McClendon says some of its products seem to hold promise.

But burying substations or building a barn around them would come at too high a cost for a 13,500-meter co-op, he says. They took some bids on metal fencing designed to stop or deflect bullets, but the price tag came in at $300,000 just for Buckskin, and he’s got 47 other substations that could use the same protection.

What’s more, McClendon says he couldn’t be sure that a bullet-stopping barrier would even work.

“The question we looked at was, is that even enough? Out in the rural areas, that still wouldn’t do it. You have a taller fence, but if someone really wants to, they’ll just pull up to it, climb on top of their pickup, and shoot over the top.”

McClendon agrees with Fiskerud, though, that the world has changed. Somewhere along the line, Garkane Energy may just have to pay whatever it takes to stay secure and resilient, he says.

“It’s just like the old distribution question about overhead versus underground lines,” McClendon says. “I don’t see how it can be affordable. It would raise the costs so high, it would be hard to pass on to our members. But that’s where this world is going, [like] all the extra costs of security at airports and other places because of the things that are happening in our country, people trying to disrupt our way of life. It could be the cost of electricity has to go up just to protect us. I hope that isn’t the way we have to go, but it may be.”

Back in September, Garkane Energy took one more step to safeguard its substation, and a low-tech, old-fashioned one at that. At McClendon’s request, the board authorized a $50,000 reward for information leading to the shooter’s arrest and conviction.

“I figured anyone who would do something like that would be the kind of person who’d talk about it too,” McClendon says.

He was right. In mid-February, a federal grand jury in Salt Lake City returned an indictment in the case, charging a 57-year-old man from Escalante, Utah, with one count of destruction of an energy facility, one count of possession of a firearm after a felony conviction, and one count of possession of marijuana.

On the energy facility charge alone, he faces up to 20 years behind bars.

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