Patent ID: 6667691
Filing Date: 2003-12-23
Classification: H02H

Abstract:
A method for the early detection of faults in an electric supply system, comprising the steps of:continuously checking the existence of RF transients on the electric supply system line; transforming detected transients whose amplitude is above a predetermined level, into a sequence of pulses; analyzing the temporal spacing between pulses to identify those which are due to dimmers, and disregarding them; identifying short-noisy states structures in said sequence, states whose duration is shorter than a period T-ARC; determining short-noisy states where the current amplitudes before and after said states are different, and disregarding these states considered to be caused by normal switching operations; regarding each of the remaining short-noisy states as a faulty event and accumulating such events in a first register; identifying separately long-noisy states in said sequence, states whose duration is longer than a period T-ARC; ascribing a number of arcing events to each long-noisy state proportional to its duration, and accumulating these numbers in a second register; and summing the values in said first and second registers, and if the sum exceeds a predetermined value N-ALARM, within a predetermined period, activating an alarm and/or a current breaker.