Patent ID: 6751528
Filing Date: 2004-06-15
Classification: G01R,H02H

Abstract:
An electronically controlled circuit breaker comprising:a line current sensor sensing line current signals; a processor for determining the fundamental frequency of the current signals, wherein the processor processes a preselected number of multiples of the fundamental frequency, and squares and sums the multiples to yield even, odd, and fundamental values; even, odd, and fundamental bins within the processor for receiving the even, odd, and fundamental values, wherein the processor processes even arc signals and non-harmonic arc signals from the even, odd, and fundamental values in the bins; and, an expert arc algorithm within the processor having an accumulator for calculating an incremental value based on even arc signal and non-harmonic arc signal input, and additionally wherein the processor applies an acceleration factor to the incremental value when both an even arc threshold and a non-harmonic arc threshold are exceeded by the even arc signal and the non-harmonic arc signal, respectively, and a fixed threshold for which to compare the incremental value; wherein the processor issues a trip signal when the fixed threshold is exceeded by the incremental value.