The attacks on two power substations in Moore County last weekend came amid a years-long effort by Duke Energy to “harden the grid” and reduce the number and severity of power outages.
Much of this effort is focused not on sabotage, but on more common and widespread threats to the power system, including hurricanes, ice storms, and squirrels.
More than five years ago, the utility began strengthening vulnerable power poles, lines and substations against wind, flooding and animal attacks. It has also begun installing a network of sensors and switches that can automatically reroute power around damaged parts of the grid, what the company calls “self-healing technology” that aims to minimize outages.
“If a tree falls on one of our main power lines, you could see 2,000 customers currently without power until those repairs are completed and the line is back in service,” said Pres. Company Secretary Jeff Brooks. “But with smart self-healing technology, we can reduce these impacts by as much as 75% and can often restore power to these customers in less than a minute.”
A self-healing system has not yet been installed in Moore County, Brooks said, and it’s unclear if it would make a difference if it did. Having a large number of damaged transformers and other equipment at two substations at the same time greatly reduces the ability to reroute power.
Over 45,000 homes and businesses out of power on Saturday evening when someone fired cannons at substations in various parts of Moore County. The company was able to repair and replacement of some equipment starting Sunday but it took several days to replace and re-energize the larger parts. More than 30,000 customers were without power Wednesday morning, the day Duke completed the final repairs. Power was restored by the end of the day.
But self-healing technology has shown advantages elsewhere.
When Hurricane Ian hit the Carolinas in September, Duke says the systems helped automatically restore power to more than 100,000 customers in two states, allowing teams on the ground to focus on critical repairs. In Florida, where Ian devastated part of the Gulf Coast, Duke says the technology helped him get all customers back online within three days, allowing his crews and contractors to help the local electric cooperative in the affected Lee County around Fort Myers.
Only about 30% of Duke Energy’s customers are served by parts of the grid that are self-healing, Brooks said, and the company hopes to increase that to more than 80% within five years. The company expects to spend tens of billions of dollars over the next decade to modernize and strengthen the network in the six states where it does business, he said.
The changes will also help Duke adapt to renewable energy sources
The sensors and switches that allow the company to redirect energy also allow it to receive it from other sources, such as solar and wind farms. These renewable energy sources can appear throughout Duke’s service area and feed electricity into the grid at different times and at different rates.
“They’re pushing the government in directions it’s never gone before,” Brooks said. “Energy has always flowed in one direction, from the power plant to the consumer. Now we see these generation sources distributed across the grid.”
Duke’s efforts to strengthen the power grid began when North Carolina experienced historic hurricanes – 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 the water to recede before they could restore power. Duke says it is installing flood barriers and, in some cases, erecting or relocating flood-prone stations.
Duke Energy will respond in kind to Moore County’s attacks, Brooks said. The company would not discuss what security measures it currently uses around its substations or what it may introduce to strengthen its equipment against gunfire in the future.
“Security is an evolutionary process,” Brooks said. “You’re always working to stay ahead of the next threat. You always gather information from events that occur on your own system. You’re gathering knowledge from peer utilities to incorporate best practices, and you’re liaising with information you receive from state and federal agencies, all of which help Duke Energy plan its safety strategy.”
As for animals, Duke says he puts up barriers around key pieces of equipment to keep out squirrels, snakes and other critters. The company also enables grid operators to reset circuit breakers remotely, so if an animal trips one, the team doesn’t have to go to the substation and do it manually.
Duke Energy is working to harden the grid against threats
Source link Duke Energy is working to harden the grid against threats