Nutty problems attributed partly to critters just doing their things.
Even with the best maintenance programs, power outages are a fact of life in the electric utility industry.
Routine performance-based maintenance helps keep the transmission and distribution systems in good operating condition, but when something starts showing signs of weakness, OPPD employees do their own kind of detective work to minimize similar problems in the future. OPPD tracks outage causes because these findings can lead to future solutions.
Did you know 18 percent of OPPD’s power outages in 2012 were caused by critters? Yes, squirrels, raccoons, birds, rabbits, bats, snakes and other creatures were behind 1,083 of the total 5,970 outages last year.
The number of these critter outages has dropped in recent years, thanks largely to creature-guarding devices that we install on the equipment, according to Rick Kalina, manager of System Operations.
How do these animals cause outages? A squirrel’s tail may hit a wire, causing a short and blowing a fuse. Hawks and other birds leave their prey atop energized equipment. Snakes get into padmount equipment. Rabbits and rodents chew through underground cable. When critters interfere with equipment, they can cause a momentary outage, or worse. Creature guards have proven effective.
The OPPD employee who found the critter culprit on a capacitor at 94th & F streets probably didn’t believe his eyes: a fish. Apparently, a bird dropped its catch-of-the-day there, leading to temporary problems for nearby industrial customers.
Another fish story involves great blue herons, who prefer to nest in tall trees – or tall transmission structures as OPPD personnel discovered. A transmission line by the Platte River kept tripping, which initially stumped OPPD personnel. After a little more detective work and a look through some binoculars, they discovered the birds were nesting in the transmission structures and their droppings on electrical insulators were causing problems.
“We try to get ahead of the problem,” said Kalina. “There are a lot of causes, but we can take measures to minimize similar problems in the future.”
In addition to creatures, outage causes include designations such as; weather, equipment, trees, vehicle, human and unknown.
Windy days provide evidence of areas where tree trimming is needed, said Kalina. “When we start seeing problems with trees contacting power lines, we send Forestry to that area. We continually work to trim areas proactively to avoid this type of outages.
There’s not much you can do to protect against 70-mile-per-hour winds, ice or heavy blankets of snow that accompany many Midwestern blizzards. This type of weather brings down trees, which oftentimes take down power lines with them. In 2012, 10 percent of the outages were attributed to trees.
A routine tree trimming program and a program to educate customers about planting the right trees around power lines have helped keep the tree-related outages down.
In 2012, weather caused 22 percent of the outages. February and December brought storms with high winds and heavy snow. OPPD crews cleaned up the latter mess just in time for the Christmas holiday. A series of thunderstorms during the summer also played havoc with the system, even interrupting Father’s Day.
“Our office handles the day-to-day management of the system,” Kalina said. “But when a big storm hits, we call in our storm team to help coordinate the resources in a centralized area. It has proven very effective.”
The remainder of 2012 outages were caused by equipment failures (19%), human (3%), vehicle (1%) and unknown (27%).
Proactive Effort Concentrates on Faults and Fixes on System
OPPD has a group tasked with tracking reliability-related events on the system; looking for proactive measures to prevent future power interruptions and equipment damage, according to Kalina.
“Asset Management & Maintenance tracks faults that occur during the year,” he said. “When they get one or two failures at a location, they investigate and may recommend crews replace cable before it fails multiple times and leads to bigger problems.”
The T&D system is a sprawling geographic network of electrical conductors and equipment that, over time, can behave in complex ways, according to Mike Wilson, manager of Asset Management & Maintenance.
Wilson’s team proactively monitors the physical condition of the T&D system and tracks performance by monitoring how many customers have very long outages, how many customers have three or more sustained outages, and how many customers experience momentary outages on a circuit over various periods of time.
The team also frequently works on specific issues with customers while diagnosing power quality/reliability issues, looking for causes and opportunities to reduce the chance of an outage. His team uses sophisticated equipment and expertise to determine if there is something that needs to be addressed on our side of the meter (line side) or if the customer has something to investigate on their side of the meter (load side).
“Ultimately, the goal is to determine where improvement investments should be made to maintain good system performance at the lowest possible cost for our customer-owners,” said Wilson.