North Carolina ranks among the nation’s fastest-growing states. With optimal business locations, excellent education opportunities, quickly developing neighborhoods, state-of-the-art health care and beautiful natural scenery, it is a perfect destination for both relocation and vacation. For the state to remain sought after, though, it needs an electricity network that can be trusted.
North Carolina electric utilities work tirelessly to make sure the lights stay on from the mountains to the coast. Outages, however, are inevitable. Extreme weather events have been on the rise across the state in recent years, and trees, squirrels and cars provide an ever-present reliability challenge. As power systems become smarter, protecting essential facilities from the growing threat of physical and cyber attacks becomes paramount. And as our state moves to a cleaner energy future, the success of that future will be built upon advanced, resilient electric infrastructure.
In today’s all-electric world, losing power even briefly can have real impacts on families and businesses as well as on the economy and security. That’s why getting the grid to rebound quickly — making it more resilient — is critical.
“When we think about our electric grid today, we see how much people depend on electricity, both for their work and their lives,” said Jeff Brooks, Duke Energy’s grid improvement communication manager. “As we add more and more devices that rely on electricity, the tolerance for downtime is much lower, so we recognize that our customers expect us to deliver reliable power every day.”
Preventing Outages, and Limiting Them When You Can’t
At Duke Energy, grid improvement initiatives tend to fall into two main categories: strengthening activities that aim to bolster reliability and avoid outages in the first place, and resiliency measures that seek to restore power as soon as possible after a disruption.
“There are multiple layers to our grid improvement strategy,” said Brooks, “but they’re all designed to enhance overall reliability and resiliency in the communities we serve.”
On the strengthening side, Duke Energy has many tools it can deploy, from upgrading electricity poles to placing outage-prone lines underground, to adding protections around essential systems and equipment. Given the diversity of North Carolina’s communities and the assorted challenges they face, a variety of approaches is needed — the perfect solution in one location may not have the same impact in another.
In flood-prone areas of eastern North Carolina, for example, Duke Energy has installed barriers to encircle substations and keep water out, almost like a fort; in Brunswick County, a large project exchanged more than 100 wooden transmission structures, often in swampy and hard-to-reach spots, for steel; elsewhere, shielding was affixed to transmission lines to prevent buzzards from roosting on them and causing potential reliability issues.
Often, several enhancements are planned and pursued at the same time as part of a larger, optimized system. “We have learned to see the value of how these improvements integrate and work together like a system to achieve a better experience for our customers and a better energy future for our communities,” said Brooks.
Even vegetation management, often overlooked, can add a crucial reliability boost. Trimming branches and removing dangerous trees can improve line performance and reduce outages, complementing other grid improvements and further strengthening the grid.
Advanced technologies are making an important impact, too. For example, smart technology can monitor the condition and health of transformers in substations, giving Duke Energy insight into which ones may need maintenance before they fail and trigger an outage.
When the lights do go out, smart-thinking and self-healing grids can automatically reroute power to lines that are operational — think of your GPS redirecting you when there’s an accident up ahead. In addition to speeding up restorations, these systems help isolate outages so that fewer customers are affected.
“That technology can help to reduce the number of customers impacted by an outage by as much as 75% and can often restore power in less than a minute,” said Brooks.
|Duke Energy’s NC Self Optimizing Grid Program Avoided Customer Outages|
|Date Range||Avoided Extended Outages||Total Outage Time Avoided|
|January 1 – June 30, 2021||90,000||Over 185,000 hours (11.2 million minutes)|
Only about 20% of Duke Energy’s customers are currently served by self-healing networks across the state, according to Brooks, but the utility hopes to expand to at least 80% of its base over the next few years.
This same technology is enabling two-way, dynamic power flow that supports other grid resources, such as solar power, battery storage and electric vehicles. In Hot Springs, a solar and battery-powered microgrid will aid the electric system and act as a backup if the town loses its main power source. Smaller microgrids are also being used at key facilities to keep operations up and running, with usage expected to grow steadily over the next decade.
The Role of Data and Communities
The primary way Duke Energy plans its upgrades — both what to undertake and where to locate it — is through data, and lots of it. At a broader level, Duke Energy uses common industry metrics, including the System Average Interruption Duration Index (SAIDI), System Average Interruption Frequency Index (SAIFI), Customer Average Interruption Duration Index (CAIDI) and Major Event Days (MED).
But other information lets Duke Energy drill down into more fine-grained details, helping the utility pinpoint opportunities to integrate smart technologies and other improvements. For example, more localized outage data can shine a light on which specific segments of a power line might benefit from targeted undergrounding, saving time and money.
Data isn’t used in isolation, though, as communities can have specific needs that are not always represented in the numbers. “We really want the data to drive our improvement strategy, but we also want to listen to the needs and interests of our communities,” said Brooks.
One aspect of this community-focused resiliency can be seen in the form of resiliency pockets, which are parts of a town that have essential services and are more likely to be served by smart-thinking and additional innovative grid technologies. If the community is building a new high-priority facility — a homeless shelter, for example — Duke Energy can work with them to try to integrate the site into an existing resiliency pocket.
As our world grows more interconnected and new risks to power delivery arise, resiliency is becoming increasingly important, and it is instrumental to how Duke Energy meets the needs of its customers and prepares for its energy future. “We want every community that we serve to enjoy the same high level of reliability and service,” said Brooks. “This is a really exciting time in the electric industry. It’s a transformational time, and it’s a time when we’re building a foundation for a future we’re still discovering.”