A detector to identify a de-energized feeder among a group of live ones

A portable device is described for field use by an electric utility that would identify a de-energized feeder from among a group of live ones. The method is based on the presence of mechanical vibrations at double the line frequency in live cables. The authors describe the fundamental physical laws and some details of the electronic circuit that processes the signals picked up by the vibration sensor. A prototype was tested on the underground distribution system in New York City. The results are presented and suggest the applicability of the detecting device.<
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