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Trim cycle resource predictability: National Grid and Alabama Power at DistribuTECH 2024

Seth Colaner

Marketing Writer

  • National Grid and Alabama Power both needed a better way to prioritize trim maintenance on their diverse lines.
  • They both found new and more efficient approaches to their vegetation management by using AiDash Intelligent Vegetation Management System (IVMS).
  • They’re now better able to plan ahead with a condition-based approach and balance their costs and resources, creating consistency in their work and budgets.

For two utilities that serve vastly different geological territories, National Grid and Alabama Power faced similar headwinds and found themselves looking for better ways to manage their trim cycles.

Different geographies looking for the same solutions

National Grid serves 20 million people with their T&D operations in upstate New York and Massachusetts, and they have transmission lines in those states, plus Vermont and New Hampshire. Alabama Power, meanwhile, has 1.5 million customers throughout much of Alabama, with approximately 70,000 miles of overhead distribution lines and 11,000 miles of transmission lines across a 44,500 square mile territory.

National Grid’s biggest challenges emerged in 2020, when a number of back-to-back storms, specifically in their Massachusetts jurisdiction, led to one of the worst SAIDI/SAIFI performances the company had ever had.

“In conjunction with that, we were also deferring miles and circuits off our work plan because our costs were increasing at double-digit percentage rates. So, as a result, we started taking least-risk circuits off the work plan, essentially kicking the can down the road,” said Bertram Stewart (Manager of Reliability Analytics and Vegetation Strategy, National Grid) at a panel discussion at DistribuTECH 2024.

And they did that for a few years in a row — which, Stewart emphatically acknowledged, was not sustainable. They needed to make a change.

In the same discussion, Alabama Power’s Kristen Bridges (Vegetation Management and Contract Services Manager), echoed some of the challenges Stewart described — as well as some that were completely different. “We’ve got a lot of warm water vapor from the Gulf of Mexico. We’ve got a really long growing season in Alabama, and a lot of biodiversity,” she said.

They struggled to come up with an average trim cycle. “What worked in the northern part of our service territory wouldn’t necessarily be ideal for the southern part of our service territory,” she explained.

Focus on prioritization, using technology

Despite a mature, decades-old system of time-based trim cycles, these headwinds caused National Grid to consider switching to a different type of vegetation management system. “Traditionally, we’re on a time-based cycle approach for our distribution system, and pretty much for our transmission system as well,” Stewart said. But as National Grid looked forward, they could see the challenges looming.

“Our contractor rates are going to increase, climate change is going to have impacts, and things of that nature,” he said. “That’s why National Grid — 3, 4 years ago — made the change to, instead of a time-based approach, a condition-based approach.”

Alabama Power’s Bridges said something similar: “Like National Grid, we’ve traditionally always had a cycle-based approach [to vegetation management], but due to constraints, [we] really needed a way to prioritize where our resources were going.”

Both utilities looked to technological solutions.

National Grid: Reduced run miles, levelized workload

National Grid took a calculated, careful approach to finding the right technology and provider. They reached out to a number of vendors, and in 2020, they did a months-long proof of concept with AiDash Intelligent Vegetation Management System™ (IVMS).

Usually, Stewart said, you focus on just a snippet of your network with a proof of concept. But in this case, they applied AIDash IVMS to all of Massachusetts. “And the end result of the proof of concept was an actionable work plan to follow in [the next] fiscal year on our entire system in Massachusetts,” he said.

Why take such a wide approach? “We didn’t want to just look at a certain area that might not be impacted the same as the rest of the system,” explained Stewart. “We really wanted to see how the system would perform, how those metrics would perform, looking at our tree-related indices and outages, and how that translates the overall system performance.”

They used a combination of AiDash IVMS with in-house end-to-end vegetation management software and some performance dashboards they were already using. They also benefited from early buy-in from company leadership, who made sure there were project managers and engineers available. And they brought in a consultant group to help them lay out the minimum viable product (MVP) for moving forward with their pivot to a condition-based approach to vegetation management.

“What I like about the condition-based approach is having that snapshot of the system, and understanding what the condition of the system is, and identifying where you’ve got to do the work,” Stewart said. “Because on a time-based approach, frankly, you’re pruning stuff you don’t need to prune.”

In the past few years, National Grid had to cut back on the number of line miles in their trim program. But when they used AiDash IVMS, they ran the program unconstrained, so they’d get a clearer sense of the true output.

“Those outputs actually reflect the volume of work from our legacy 5-year cycle approach, which is good, because we want to levelize our workload to maintain consistency in our tree crew resources,” Stewart said.

With a condition-based approach, facilitated by AiDash IVMS, they know where to prune and when. Although in the past, National Grid had scheduled work plans and vendors just a year in advance, they’re now able to take a multi-year approach using AiDash IVMS.

“We didn’t do it just from a cost perspective,” said Stewart. “Really, to me, it’s about serving the customer and making sure their lights stay on [and that] they don’t see those interruptions as much. That’s really my goal.”

Some benefits and results National Grid experienced include:

  • 3% improvement in SAIDI/SAIFI at the system level.
  • Ability to schedule vegetation management work on a multi-year schedule.
  • Almost 85% of clearance distances per span aligned with what AiDash IVMS identified.
  • Improving IEEE benchmark performance on fewer miles.

Alabama Power: Segment-based prioritization and stabilizing resources

To solve their issues, Alabama Power developed a prioritization matrix to inform their trim plans and eventually began incorporating insights from satellites and AI, too.

“We took into account things like number of customers impacted, VM-related reliability stats, and years since last trim,” Bridges said. It was helpful, she said, but reliability is a lagging indicator, when the customer has already been impacted.

They wanted to do better. “So, we started looking into: How can we do a true condition-based program? And we need to know what the conditions are out on our whole system at [any given] time.”

They assessed the available technology solutions by looking at what fit their needs best, rather than getting lost in the lists of pros and cons of each. Then they took the time to conduct 2 pilot programs and concluded that a satellite-based tool was ideal for them.

“We actually just completed the process for creating our plans for 2024, and we started with … what we’ve been doing for the past 5 years, and did the normal prioritization. But when we brought in the satellite insights into that process, we learned that we could actually move 114 segments out of our plan,” said Bridges.

They replaced those 114 segments with 51 segments, but in total that reflected a 200-mile reduction in what needed to be trimmed.

“The other big thing is…we were strictly feeder-based. We were breaker to end of line. And we’ve now gone to a segment-based program. So, we’re hitting the worst segments on our system,” she added.

Bridges also noted that internal buy-in has been important. “It’s really exciting to see our arborists get excited about incorporating technology and new ways of thinking about how we do what we do,” she said. Their arborists are now even championing AiDash IVMS. “When they can go and tell the story in the field of why we’re doing things now the way that we’re doing it, that’s a big win for us,” Bridges added.

All that feeds into Alabama Power’s ability to keep resources stable. They’re going to be able to look at growth rate by segment, which allows them to budget years ahead. And, of course, improve the overall customer experience.

Get more information about AiDash’s Intelligent Vegetation Management System  here.

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