Patent ID: 7440245

Claim:
A method of detecting an arc fault in a power circuit, said method comprising: determining a peak amplitude of a current pulse of a current flowing in said power circuit; determining whether the peak amplitude of said current pulse is greater than a predetermined magnitude; responsively employing at least one algorithm and said peak amplitude to determine whether an are fault condition exists in said power circuit; determining that said current pulse has said peak amplitude of greater than said predetermined magnitude and responsively activating said at least one algorithm from said inactive state; employing a plurality of half-cycles of said current flowing in said power circuit including a present half-cycle and a previous half-cycle; and employing as one of said at least one algorithms: determining the peak amplitude of said current pulse for the present half-cycle and the previous half-cycle, determining that the peak amplitude of said current pulse for the previous half-cycle is greater than about zero and responsively adding an amount equivalent to an increase in said peak amplitude from the previous half cycle to the present half-cycle to an accumulator, and otherwise, adding an amount equivalent to said peak amplitude of said present half-cycle to said accumulator, decaying the amount stored in said accumulator over time, and determining an arc fault condition in said power circuit if the amount stored in said accumulator exceeds a predetermined value.