While some of the biggest causes of electrical outages are from events that happen without much warning, such as tornadoes, improving reliability doesn’t happen by chance.
When you look at aggregate outage data compiled by the Energy Information Administration, the reliability of public power suppliers beats that of cooperatives and investor-owned utilities. Among the public power providers recognized for reliability by the American Public Power Association, there’s often a common denominator: Many use the eReliability Tracker, a service for collecting, organizing, and summarizing outage information that was first released in 2013. The tracker lets utility managers delve deep into the causes of outages and the areas they hit most. Here’s how three long-time users have leveraged the data.
Keeping Track of the Details
Since many users of the eReliability Tracker are inputting data manually rather than having it imported automatically from an outage management system, choosing what to put into the tool is a personal decision.
“I know a town close to us that doesn’t count it as an outage unless they have to roll a truck, but we do it a little differently,” said Josh Roberts, operator mechanic, special services for Macon Municipal Utilities, which keeps power on for around 3,200 homes and businesses in Macon, Missouri. “We count all of our outages, especially now that we have smart metering.” He’s talking about momentary outages as well as partial power at someone’s home, which can happen when damage shorts out one of the three lines feeding a customer’s breaker box.
Electric Superintendent Al Sullivan of Bryan Municipal Utilities in Ohio also tracks everything for the system that serves about 6,000 meters. “Whether it be an instantaneous or a sustained outage, we call it an operation, something that opened the circuit up.”
“We could just put all our outage information into a spreadsheet, put some formulas in there, and do this ourselves,” said Jeff Teel, director of engineering, operations, and technology at Northern Wasco County People’s Utility District, which delivers electricity to nearly 25,000 people and businesses in Wasco County, Oregon. “If we did our own spreadsheets, we wouldn’t get the ability to quickly sort and filter data based on different criteria.”
By putting every detail into the tracker, “we can calculate systemwide or one feeder’s reliability over the previous five years,” said Teel. “Is it getting better? Is it getting worse despite the investments we’re putting into it? The tracker takes all the outage information you put in there and does the calculations for you. It does them on the fly as you filter the data.”
How Data Delivers Value
Having the data at your fingertips is only valuable if you can turn it into useable information. Predictive maintenance is one popular application for using outage and reliability data.
In heavily wooded Macon, some 80% of outages can be traced back to squirrels and other wildlife, Roberts said. “When we first started tracking outage data, we really used it to figure out where squirrel guards needed to be on our power lines,” he explained. “We could graph the data, and it would show exactly which circuit was having the most problems. That was invaluable.”
In Ohio, Sullivan also uses the data to see where animal guards should be placed, and he also looks for spots where tree-trimming operations might be needed. “When we see a lot of outages due to tree limbs hitting power lines, we know it might be time to budget a little more money next year on trimming to make sure we’re getting the limbs cut back far enough,” he said.
Investment planning is another common use for reliability data. “We use that data to help us prioritize where we’ll invest capital funds,” Teel said. He and his team run reports on every feeder. They also use SCADA data in their evaluations because it allows the planning team to “monitor increases or decreases in loading throughout the system,” so they’ll know if assets are properly sized.
Bryan Municipal’s team tracks faults on underground power lines because the city tries to complete a few underground replacement projects each year. “Thirty or 40 years ago, we direct-buried everything,” Sullivan said. Along with direct burial, the utility used concentric neutral conductors, which sit outside the power line cable without a protective coating like the type installed today. The bare, exposed neutrals can corrode. “We have areas where we lose that neutral, and it causes the line to fail,” Sullivan said.
Along with investments, the Bryan team uses reliability data to plan purchases. “We just ordered single-phase pad-mount transformers here recently, and it will take more than a year to get them, Sullivan noted. “We’re tracking how many transformers we’ll need each year. You really have to plan ahead.”
Roberts uses data to plan operations. “If we know the outage wasn’t a squirrel or tree limbs, then we start looking at equipment,” he said. “We do thermal imaging, so the tracker helps us see where we need to send crews to check if the line is breaking down.”
When it comes to service for commercial and industrial clients, tracker data can provide better service. “If a factory in town is claiming that they’ve had a lot of operations over the past year, we search through the data and have a good record to use when explaining things to them,” Sullivan explained. By operations, he means lost power on the entire substation circuit, whether instantaneous, momentary, or sustained. “These customers want to know if the issue is going to be recurring and what we’re doing about it. The tracker helps us give them good and accurate data.”
Finally, the tracker data gets used for board reporting in both Macon and Northern Wasco County. “Every month, our board members get reliability numbers for the previous 12 consecutive months, and once a year, I give a presentation,” said Teel. “They’re our governing body, and it’s important for them to understand these numbers. I explain what reliability indices mean and where we stand compared to other utilities.”
Results From Data-Driven Decisions
Northern Wasco County PUD has been using the tracker since 2015, and Teel said using the data in decision-making has paid off. “One thing we identified as a major cause of outages is solid copper wire in our system that was installed many years ago,” he noted. “It gets very brittle and has a tendency to break in winter storms.” The utility used this information to prioritize the replacement of copper wire in as many power lines as feasible. “For the past two winters, we’ve seen a marked decrease in outages due to broken copper wire.”
The PUD also has had troubles with large migrating birds — mostly raptors, such as osprey. Finding this correlation through the data made the utility change its construction standards on power poles. “The crossarms on top of the poles are longer, so the wires are spread wider apart from each other, and the clearance between the wires is greater,” Teel explained. “We’ve seen reliability improvements as a result of those actions.”
Macon’s investments have had an impact, too. “The squirrel guards have prevented a lot of momentary outages,” Roberts said. “Ten years ago, we would have about 70 outages a year, 80% of them momentary. Now we have 30 to 40 outages a year, with better than 80% of them momentary.”
Similar results are showing up in Bryan, Ohio. “We’ve really hit our tree trimming hard,” said Sullivan. “Now we don’t have as many lights flickering during windstorms or operations due to limbs blowing onto the lines.” He added that they still see instantaneous outages due to squirrels, but the sustained outages from limbs taking down lines have reduced considerably. “We just don’t see as many of those anymore.”
Benchmarking Benefits
Utilities subscribed to the eReliability Tracker receive a personalized annual benchmarking report that uses data from the service to let utilities see how they do in comparison to other utilities’ reliability indices.
Sullivan looks at the benchmarking to see how Bryan Municipal Utilities is doing compared to other public power utilities in the region.
Teel does, too. “If we see our outage durations and outage frequencies go up — which is bad — we don’t know if that is due to something in our system or something else,” he said. “When we can benchmark it with other utilities and see they saw similar jumps, it gives context to the numbers. Maybe it was just a bad winter.”
Roberts said he doesn’t look at the report much because while Macon counts momentary outages in its figures, others in the area don’t, so it’s not an apples-to-apples comparison.
Teel also noticed the PUD beat others when it came to frequency and duration of outages, but it was lagging in terms of the customer average interruption duration index, which reflects the average service restoration time. “Seeing that made me think about what we might need to do about this,” Teel said. “Do we need to increase staff? Is there something else we need to do?”
Having seen this comparison for two years now, the PUD is starting to explore options. The team is considering using drone cameras for enhanced system inspection. It’s also looking at adding switching equipment and reclosers.
“Our mission is to provide reliable, competitively priced energy and related services that benefit our customers,” Teel said, and his interpretation of that mission is simple. “We want to give people the highest reliability at the lowest cost possible, so we have to target investments in the areas that need them.”
Tracking pinpoints those areas. “It helps us understand where we need to address issues,” he added.
