Arc detection using current variation

摘要: In an electric circuit supplying AC line current rent to a load (30, 31) from source (26) of given frequency providing repetitive cycles, arc detection is provided by sensing cycle changes in the current. The sampled with harmonic notch filter (72) at plurality n phases Θ 1 through during each m cycles (26), provide currents I ,m, where phase and cycle. differences (I ,m)-(I ,m-x), x designated number difference signals. absolute values these signals ID are accumulated synchronous summer (94) over cycles. An indicative signal generated response conditions combinations (116) cumulative ID. Cycle voltage also sensed (146), disarmed condition. further embodiments, subcycle sensed.