Patent ID: 6292340
Filing Date: 2001-09-18
Classification: H02H

Abstract:
For use in an electric power distribution system having an overcurrent protection arrangement, a host computer and a plurality of branches each including one or more conductors, a method for detecting and isolating a high impedance fault which has not been de-energized by said overcurrent protection arrangement, said method comprising the steps of:continuously monitoring an AC voltage in remote conductors in the electric power distribution system for detecting a change in AC voltage status in a conductor in the electric power distribution system;comparing a change in the AC voltage status in a conductor in the electric power distribution system with a predetermined voltage level;providing identifying indicia and voltage status condition information to the host computer for a conductor in a given branch having a change in AC voltage status less than said predetermined voltage level;interrogating other conductors in said given branch adjacent to the conductor having said change in AC voltage status to determine the location in said given branch of the conductor having said change in AC voltage status; andcomparing the duration of a change in AC voltage status greater than said predetermined voltage level in a conductor with a selected time delay and providing said trip signal when the change in AC voltage status exceeds said predetermined voltage level for a duration greater than said selected time delay for de-energizing and isolating the conductor having the detected change in AC voltage status less than said predetermined voltage level from the remaining portion of the electric power distribution system.