Steve Casios (left), Sr. Distribution Engineer, and Fabian Richards, Manager of Distribution Planning and Reliability Engineering, check a FLISR control unit.

When OUC installed a “self-healing” grid technology as a pilot program in the Rosemont community in 2019, project engineers hoped that it would help lessen the impact of power disruptions to the area.

Which it did, exceeding their expectations.

OUC saw a 94% reduction in the number of Rosemont customers affected by outages during the 13-month trial of FLISR (Fault Location, Isolation, Service Restoration), a software-based Smart Grid system. From 2016 until FLISR was launched in June 2019, a total of 13,542 customers were impacted by outage incidents compared with 829 during the test period that ended on Aug. 17, 2020.

Complementing that dramatic improvement in service reliability were two more impressive stats: a 92% decrease in customer-minutes of interruption (CMI), a key measurement of outage duration, and 73% fewer momentary service interruptions.

“This system did exactly what we had hoped it would do, and it performed better than we expected,” said Fabian Richards, Manager of Distribution Planning and Reliability Engineering. “We’re now installing FLISR in other areas where we want to improve reliability and resiliency. The Rosemont pilot was an excellent learning experience for moving forward with FLISR.”

FLISR technology communicates with reclosers (seen here mounted on a pole) when a fault occurs and seeks to minimize the numbers of customers impacted by an outage.

OUC chose Rosemont as the FLISR test site because the north Orlando neighborhood had a history of power disruptions occurring more frequently than other areas. FLISR automatically reconfigures the flow of electricity after a fault occurs so fewer customers are impacted by an outage. The system also locates the area of a fault, which helps crews save time on finding and repairing damaged power lines. Trees interacting with overhead power lines were often the cause of service interruptions in Rosemont.

Steve Casios, Sr. Distribution Engineer, led the $1.1 million Rosemont pilot program and is the project manager on the new FLISR installation in MetroWest. OUC also is adding FLISR to other underperforming circuits in the Millenia mall area and Azalea Park. The three projects are expected to be completed later this year.

In the new installations, the FLISR units will use cellular service to communicate with each other and not radios, as was done in Rosemont. “There’s a cost benefit to using cellular; radio communication is very expensive,” said Casios. “The switch will not affect performance.”

FLISR systems are usually installed on utility poles, but some will be ground mounted in MetroWest to improve reliability of the community’s underground electric infrastructure.

Because so much planning, training and coordination across multiple OUC departments go into installing, maintaining and operating FLISR systems, Richards and Casios are recommending OUC dedicate skilled personnel to maintain them.

“Having a dedicated team of FLISR specialists is one of the best practices that came out of our Rosemont trial,” said Richards. “FLISR is not traditional electric utility technology. It requires a lot of education and training before you can deploy it in the field.”

OUC’s continuing investment in FLISR, added Casios, “will benefit a lot of our customers, although most won’t ever notice the difference in their electric service. Most customers on a circuit won’t know if there’s been a service disruption, and that’s the whole point of using FLISR. It’s a game-changer in ensuring reliability.”