September 25, 2007

White Paper: Advancing the State of Looped Distribution Feeders

A common practice for improving electric service reliability is to provide an alternate source of supply. On the distribution system, two feeders, each with one or more mid-line overcurrent protective devices, can be tied together through a normally-open tie point to restore service to the unfaulted sections of line. Conventional looped distribution systems rely on overcurrent coordination to ensure that the correct device in a loop clears a particular fault. However, properly coordinating a large number of devices in series has practical limitations. This paper introduces a new technology — referred to as pulseclosing — that enhances the conventional loop system concept by testing the line for a fault without actually reclosing into the fault.