A fuse so smart, it repairs itself
Squirrels. Branches. Lightning. They are the common enemies of electric utilities, causing an estimated 60 percent to 80 percent of power outages.
They disrupt the grid everywhere. The damage they cause the system is most often minor and easily fixed, yet they pose an expensive dilemma.
(Al Podgorski/Sun-Times)
Their contact with power lines might be brief, and the blown fuse that results is sticker priced only around $6. But Michael Ennis, engineering manager for the Fuse Products Division of S&C Electric Co., said dispatching a crew to fix the fuse might cost the utility around $500. Meanwhile, customers could be without power for an hour or more.
So what if somebody made a "smart fuse," one that could detect if a voltage surge is caused by one of the three aforementioned causes, and safely restore power if there is no damage to the lines?
S&C, based in a landscaped factory in Rogers Park, tackled that problem, and came up with the TripSaver Dropout Closer, its a technical name for a product designed to make utilities and their customers happier. It was introduced in March, and so far S&C has tallied more than $600,000 worth of orders from about 18 customers, including ComEd.
The TripSaver also garnered S&C a 2007 Chicago Innovation Award in recognition of its forward thinking and determination.
"S&C has long had a reputation for innovation in the utility business, and the introduction of TripSaver is a powerful reinforcement to our brand," Ennis said.
Bringing the product from the talking stage to production was no easy task. The privately held company had to come up with a cost-effective device that was easy to install and relatively lightweight so it could be moved from circuit to circuit.
His division worked closely with utilities in field trials, and redesigned the product several times. Ultimately, it's a technological improvement for the last mile of the power-plant-to-consumer connection, the part of the grid where technology is most expensive.
"Distribution automation has begun to transform the utility world, but 90 percent of the customers are still served by circuits which are not economical to automate," Ennis said. "TripSaver starts us on the road of applying smart solutions to this 'last mile' of the utility world."
Work started on the device in the 1990s, and S&C came back to it with new determination in 2003. The result is a TripSaver that weighs about 20 pounds and costs from $1,200 to $1,500.
Ennis said that compares with similar devices, called reclosers, that might weigh 150 pounds, cost much more, and aren't nearly as smart.
Utilities traditionally use reclosers to monitor several circuits. When a transitory problem such as a rain-soaked tree branch touches a line, the recloser will check all the circuits.
Ennis said that's what happens when customers see flickering lights or brief outages that can knock out computers and electronic clocks. It's the recloser tracing a problem that's on another circuit.
He said the TripSaver eliminates the interruptions for non-affected circuits. It's designed to serve only one circuit and, because of its light weight, can be easily moved to where outages are becoming more common.
"By installing a TripSaver, [utilities] can improve their outage rates, lower their ownership costs and avoid the downside of causing all of these blinks to their customers," Ennis said.
Oncor, a utility serving Dallas-Fort Worth, was the first to install TripSaver and said it worked as advertised.
"It's the type of technological advance that will improve reliability for customers over time," said Jim Greer, Oncor's vice president of asset management and engineering.
And keep the squirrels at bay and the lights on.