For Duke Energy, fortifying the grid usually means dealing with storms, not snipers

The attacks on two power substations in Moore County last weekend came amid a multi-year effort by Duke Energy to “strengthen the grid” and reduce the number and severity of power outages.

Most of that effort is aimed not at sabotage but at more common and widespread threats to the energy system, including hurricanes, ice storms and squirrels.

More than five years ago, the utility began fortifying vulnerable power poles, lines and substations against wind, flooding and animal incursions. It also began installing a network of sensors and switches that can automatically reroute power around damaged parts of the grid, something the company calls “self-healing technology” that aims to minimize outages.

“If a tree falls on one of our main power lines, you may see 2,000 customers that are out of power currently until that repair is completed and the line put back into service,” company spokesman Jeff Brooks said in an interview. “But with smart self-healing technology, we can reduce those impacts by as much as 75% and can often restore power to those customers in less than a minute.”

The self-healing system is not yet installed in Moore County, Brooks said, and it’s not clear that it would have made any difference if it had been. Having so many transformers and other pieces of equipment damaged at two substations at once greatly reduces the options for rerouting electricity.

More than 45,000 homes and businesses lost power Saturday evening when someone fired guns into the substations in different parts of Moore County. The company was able to repair and replace some equipment starting Sunday but needed several days to replace and re-energize larger pieces. More than 30,000 customers remained without power Wednesday morning, the day Duke completed the final repairs. Power was restored by the end of the day.

But the self-healing technology has shown benefits elsewhere.

When Hurricane Ian hit the Carolinas in September, Duke says the systems helped to automatically restore power to more than 100,000 customers in the two states, allowing crews in the field to focus on critical repairs. In Florida, where Ian devastated parts of the Gulf Coast, Duke says the technology helped it get all of its customers back online within three days, allowing its crews and contractors to assist the local electric cooperative in hard-hit Lee County around Fort Myers.

Only about 30% of Duke Energy customers are served by self-healing parts of the grid, Brooks said, and the company hopes to expand that to more than 80% within five years. The company expects to spend tens of billions of dollars over the next decade modernizing and strengthening the grid in the six states where it does business, he said.

Changes will also help Duke adapt to renewable energy

The sensors and switches that allow the company to reroute power also make it possible to accept it from other sources, such as solar and wind farms. These renewable sources of energy can pop up throughout Duke’s service area and contribute power to the grid at various times and rates.

“They’re pushing power in directions that it’s never gone before,” Brooks said. “It has always been power going in one direction, from a power plant to a customer. Now we’re seeing those generation sources distributed out across the grid.”

Duke’s efforts to strengthen the grid were getting started as North Carolina endured historic hurricanes back-to-back — Matthew in 2016 and Florence in 2018. The storms highlighted where poles and power lines were most vulnerable and where it made sense to replace wooden poles with steel or bury lines underground.

Florence also flooded several substations in North Carolina, forcing repair crews to wait days for water to recede before they could restore power. Duke says it is installing flood barriers or in some cases raising or relocating flood-prone stations.

Duke Energy will respond the same way to Moore County attacks, Brooks said. The company won’t discuss what security measures it has now around its substations or what it might put in place to harden its equipment against gunfire in the future.

“Security is an evolutionary process,” Brooks said. “You always work to stay ahead of the next threat. You always gather learnings from events that occur on your own system. You gather knowledge from your peer utilities to incorporate best practices, and you stay connected to intelligence you receive from state and federal agencies, and all of that helps Duke Energy plan a security strategy.”

As for animals, Duke says it is installing barriers around key pieces of equipment to keep out squirrels, snakes and other critters. The company is also making it possible for grid operators to reset circuit breakers remotely, so when an animal does set one off a crew doesn’t have to drive out to a substation and do it manually.