US 11,942,774 B2
Arc fault detector
Werner Dichler, Grossschoenau (AT); and Guenter Martinek, Vienna (AT)
Assigned to EATON INTELLIGENT POWER LIMITED, Dublin (IE)
Appl. No. 17/604,773
Filed by Eaton Intelligent Power Limited, Dublin (IE)
PCT Filed Apr. 23, 2020, PCT No. PCT/EP2020/061352
§ 371(c)(1), (2) Date Oct. 19, 2021,
PCT Pub. No. WO2020/216853, PCT Pub. Date Oct. 29, 2020.
Claims priority of application No. 1905751 (GB), filed on Apr. 25, 2019.
Prior Publication US 2022/0181864 A1, Jun. 9, 2022
Int. Cl. G01R 31/52 (2020.01); G01R 31/14 (2006.01); H02H 1/00 (2006.01)
CPC H02H 1/0015 (2013.01) [G01R 31/14 (2013.01); G01R 31/52 (2020.01)] 9 Claims
OG exemplary drawing
 
1. An arc fault detector, the arc fault detector comprising:
a first electric line;
a first sensor configured to: monitor an electric current or voltage spectrum in the first electric line and output a broadband measurement signal with a bandwidth from at least 10 Hz to 10 MHz;
a signal-pattern-analyser configured to: compare the broadband measurement signal with at least a first predefined arc pattern, and output a first arc-detection-signal on a first output in a case where the broadband measurement signal matches the arc pattern;
a slew-rate-detector configured to: determine a slew rate of the electric current in the first electric line, compare the determined slew rate with a threshold slew rate, and output a slew-rate-detection-signal on a second output in a case where the determined slew rate is higher than the threshold slew rate;
an envelope-step-detector configured to determine a change of an envelope-value of at least a predefined frequency band of the broadband measurement signal within a predefined timespan, the envelope-step-detector comprising:
an input,
a band-pass-filter arranged at the input, and
an envelope determination unit comprising a rectifier coupled to an exit of the band-pass-filter, the envelope determination unit being configured to detect maximum values of a rectified signal and interpolate a curve along the maximum values to build an envelope,
wherein the envelope-step-detector is further configured to differentiate the envelope and to output an envelope-step-detection-signal on a third output in a case that the determined change is higher than a threshold change;
a first controller connected to the second output and the third output, the first controller being configured to output a second arc-detection-signal on a fourth output in a case where the first controller receives the slew-rate detection signal and the frequency-detection-signal within a first predefined detection-time-window; and
a second controller connected to the first output and the fourth output, the second controller being configured to output a trigger signal on a trigger output in a case where the second controller receives the first arc-detection-signal and the second arc-detection-signal for at least a defined total time within a second predefined detection-time-window,
wherein the electric current and/or voltage in the first electric line are evaluated in parallel in the signal-pattern-analyser, the slew-rate-detector, and the envelope-step-detector.