Method for identifying arcing faults and circuit breaker

Patent metadata

Field	Value
Publication number	US-2016248240-A1
Application number	US-201313974416-A
Country	US
Kind code	A1
Filing date	Aug 23, 2013
Priority date	Feb 23, 2011
Publication date	Aug 25, 2016
Grant date	—

Abstract

A method for identifying arcing faults within a circuit having a system frequency, an electrical current and an electrical voltage, in which method an interference signal occurring, which has a frequency below an LF1 frequency and a current intensity above an LF1 limit threshold, defines an LF1 signal, in which a number of interference signals occurring, which have a frequency below an HF2 frequency, are combined to form an HF2 signal if the number of interference signals occurring is greater than or equal to an HF2 number and the time interval between two successive interference signals is less than an HF2 time, in which the number of time periods with a respective length which amounts to an accumulation length and which follow one another directly in time and in which in each case at least one HF2 signal is present define an accumulation when the number of time periods is greater than or equal to an accumulation number.

First claim

What is claimed is:

1 . A method for identifying arcing faults within an electrical circuit comprising a system frequency, an electrical current, and an electrical voltage, the method comprising:
defining an LF1 signal as an interference signal occurring which has a frequency below an LF1 frequency and a current intensity of the electrical current of the electrical circuit above an LF1 limit threshold; combining a number of interference signals occurring which have a frequency below an HF2 frequency to form an HF2 signal if the number of interference signals occurring is greater than or equal to an HF2 number and a time interval between two successive interference signals is less than an HF2 time; defining an accumulation as a number of time periods that have a respective length amounting to an accumulation length and directly succeed one another temporally and within which in each case at least one HF2 signal is present, if the number of time periods is greater than or equal to an accumulation number; incrementing a WET1 accumulation counter by one if an accumulation is identified; resetting the WET1 accumulation counter to zero if the time interval between two neighboring accumulations is less than a first accumulation time or greater than a second accumulation time; starting a waiting period after an accumulation value has been reached for the WET1 accumulation counter; terminating the waiting period and resetting the WET1 accumulation counter to zero if at least one LF1 signal or two accumulations between which the time interval is less than a third accumulation time are measured within the waiting period; and identifying and/or reporting an arcing fault after the waiting period has elapsed.

2 . The method as claimed in claim 1 , wherein the waiting period is terminated if this has already begun and the WET1 accumulation counter is reset to zero and left at zero for a parallel time period if an LF2 signal is measured which has a duration longer than an LF2 limit length,
wherein an interference signal occurring which has a frequency below an LF2 frequency and a current intensity of the electrical current of the electrical circuit above an LF2 limit threshold is designated as the LF2 signal, and wherein the parallel time period is ended if a measured LF2 signal has a duration shorter than the LF2 limit length or the voltage for a first termination time span was less than a termination voltage or if no LF2 signal was measured for a second termination time span, and wherein the arcing fault is detected and/or reported:
if within the parallel time period between all successive HF2 signals, the time interval is greater than or equal to a first arcing fault time span;
if within the parallel time period between two directly successive HF2 signals, the time interval is greater than or equal to a second arcing fault time span; or
if either a number of HF2 signals was measured which is greater than or equal to a first arcing fault number if, within a third arcing fault time span, a number of LF2 signals was measured which lies between a second arcing fault number and a third arcing fault number, or if a number of HF2 signals was measured which is greater than or equal to a fourth arcing fault number if, within the third arcing fault time span, a number of LF2 signals was measured which is greater than the third arcing fault number, wherein the third arcing fault time span in each case begins with the parallel time period.

3 . A method for identifying arcing faults within an electrical circuit comprising a system frequency, an electrical current, and an electrical voltage, the method comprising:
defining an LF1 signal as an interference signal occurring which has a frequency below an LF1 frequency and a current intensity of the electrical current of the electrical circuit above an LF1 limit threshold; combining a number of interference signals occurring which have a frequency below an HF2 frequency to form an HF2 signal if the number of interference signals occurring is greater than or equal to an HF2 number and a time interval between two successive interference signals is less than an HF2 time; defining an accumulation as a number of time periods which have a respective length amounting to an accumulation length and which directly succeed one another temporally and within which in each case at least one HF2 signal is present if the number of time periods is greater than or equal to an accumulation number; incrementing a WET2 accumulation counter by one if an accumulation is identified; starting, in the case of an interval between two accumulations which interval is greater than or equal to a third accumulation time, either an LF period if the WET2 accumulation counter is greater than a first WET2 limit value or the WET2 accumulation counter is reset to zero if the WET2 accumulation counter is less than or equal to the first WET2 limit value; incrementing an LF1 counter by one if an LF1 signal is measured within the LF period; identifying and/or reporting the arcing fault if, within the LF period, the LF1 counter exceeds a second WET2 limit value; and resetting the WET2 accumulation counter and the LF1 counter to zero after the LF period has elapsed.

4 . The method as claimed in claim 3 , wherein the LF period is terminated if the LF period has already begun, the WET2 accumulation counter and the LF1 counter are reset to zero and are left at zero fora first SPG time span if either for a second SPG time span the voltage is not greater than an SPG voltage or lengths of two successive high time spans differ by more than a third SPG time span, and wherein the high time spans is the time span within which the voltage is greater than the SPG voltage.

5 . The method, as claimed in claim 3 , wherein the LF period is terminated if the LF period has already begun, the WET2 accumulation counter and the LF1 counter are reset to zero and are left at zero for a parallel time period if an LF2 signal is measured which has a duration longer than an LF2 limit length,
wherein an interference signal occurring which has a frequency below an LF2 frequency and a current intensity of the electrical current of the electrical circuit above an LF2 limit threshold is designated as LF2 signal, and wherein the parallel time period is ended if a measured LF2 signal has a duration shorter than the LF2 limit length, or the voltage for a first termination time span was less than a termination voltage, or if no LF2 signal was measured for a second termination time span, and wherein the arcing fault is detected and/or reported:
if within the parallel time period between all successive HF2 signals the time interval is greater than or equal to a first arcing fault time span,
if within the parallel time period between two directly successive HF2 signals the time interval is greater than or equal to a second arcing fault time span, and/or
if either a number of HF2 signals was measured which is greater than or equal to a first arcing fault number if, within a third arcing fault time span, a number of LF2 signals was measured which lies between a second arcing fault number and a third arcing fault number, or if a number of HF2 signals was measured which is greater than or equal to a fourth arcing fault number if, within the third arcing fault time span, a number of LF2 signals was measured which is greater than the third arcing fault number, wherein the third arcing fault time span in each case begins with the parallel time period.

6 . A method for identifying arcing faults within an electrical circuit comprising a system frequency, an electrical current and an electrical voltage, the method comprising:,
defining an LF1 signal as an interference signal occurring which has a frequency below an LF1 frequency a

Assignees

• Ellenberger & Poensgen

Inventors

• Miklis Markus

Classifications

• H02H1/00

  Details of emergency protective circuit arrangements · CPC title

• H02H1/0015 Primary

  Using arc detectors · CPC title

• H02H3/027

  with automatic disconnection after a predetermined time (H02H3/033, H02H3/06 take precedence {; timing in overcurrent protection circuits H02H3/093; in undervoltage protection circuits H02H3/247; staggered disconnection H02H7/30}) · CPC title

• G01R31/1272 Primary

  of cable, line or wire insulation, e.g. using partial discharge measurements (locating faults in cables G01R31/083) · CPC title

• G01R31/025

  Physics · mapped topic