Knoxville Utilities Board was looking for ways to make power more dependable both at the residential and commercial level. For the commercial application they chose to use the Siemens Auto Transfer Scheme (ATO). This utilized two or more Siemens reclosers from separate sources providing power for a single facility or even an area where they could not afford to lose power. The transfer happens in less than 6 cycles or 100 ms to provide virtually un-interruptible power. At the residential level KUB has utilized Siemens reclosers in a Fault Location, Isolation, and Service Restoration (FLISR) scheme. Where numerous reclosers are deployed in a loop from multiple sources with a normally open point to locate the fault and isolate it and return power to as many customers as possible. Both projects use Siemens smart relays and 61850 protocol using both fiber and LTE cell network.
