Distribution Line Ground Fault Prevention With Blown Fuse Protection On Single Phase

A system for preventing ground fault or other short circuit in electric distribution line system, caused by a break in a line, utilizing programmable relay protection in a plurality of relay devices programmed to monitor high sensitivity parameters, includes blown fuse protection in a single phase tap line to prevent false operation of the open conductor logic when a tap line fuse successfully interrupts a short circuit on the tap line, which includes: blown fuse protection subsystem having relay devices on the tap lines (vis transformers) that have microprocessors programmed to detect changes in negative sequence overcurrent on a single phase tap line, to calculate the change in negative sequence overcurrent, to store a preset acceptable range for change of negative sequence overcurrent, to compare the calculated change in negative sequence overcurrent to the preset acceptable range for change of negative sequence overcurrent.