Open conductor detector system

Abstract

An open phase conductor detector system is described consisting of one or more transmitters and a receiver which communicate through the distribution line neutral conductor. The transmitter(s) detects the open phase conductor by monitoring the phase conductor voltage using redundant inputs. When an open phase conductor is detected, the transmitter injects a signal to the distribution line neutral conductor by means of a coupling current transformer (CT). The signal is frequency and duration coded. The receiver decodes the signal and generates a trip signal which may activate a breaker, a ground switch, or a recloser causing isolation of the distribution line with the open (downed) phase conductor. The system is presently implemented for single distribution lines. A prototype open conductor detector system has been constructed and field tested on a Georgia Power Company distribution system. conductors. Most of the faults occur on laterals rather than on the main three phase distribution line. Line crews have reported that about one-third to one-half of the downed conductor faults are not cleared by the installed protective devices. This means that approximately six percent of all distribution faults involve undetected downed conductors.

Double‐ended technique for distinguishing series faults from shunt faults on transmission lines using the sequential components of impedance

“…Most of the methods proposed so far aim at detecting fallen conductors after a series fault occurs. These methods can indeed cope with high-impedance faults, which are considered as shunt faults [2][3][4][5][6][7], but are not applicable when there is a mal-operation of single-phase switchgears. In [8], Wang et al utilised the negativesequence pilot protection modified for detecting open phase on transmission lines.…”