Patent ID: 6459269
Filing Date: 2002-10-01
Classification: G01R,H02H

Abstract:
A method of controlling a load in response to a ground fault condition, said method comprising the steps of:measuring a ground fault alternating current flowing from the load; ascertaining a real part and an imaginary part of the ground fault alternating current, including the step of determining a phase angle of the ground fault alternating current relative to a branch current entering the load, said determining step comprising the sub-steps of: ascertaining a period of at least one of the ground fault alternating current, the branch current and a branch voltage; measuring a time period between a zero-crossing of the ground fault alternating current and a zero-crossing of the branch current; and dividing the time period by the period of at least one of the ground fault alternating current and the branch current; and at least one of removing electrical power from the load and indicating the ground fault condition to a user if at least one of: a magnitude of the real part exceeds a first predetermined threshold; and a magnitude of the imaginary part exceeds a second predetermined threshold.