Patent ID: 9705304
Date: 2017-07-11
CPC Classifications: G01R,H02H

Claim:
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: detecting, by a processor, an interference signal; classifying, by the processor, each of the detected interference signal as a first signal if the interference signal occurring has a frequency below a first frequency and if a current intensity of the electrical current of the electrical circuit is above a current limit threshold, and as a second signal if the interference signal has a frequency below a second frequency; combining, by the processor, a number of second signals to form an HF2 signal if the number of the second signals occurring is greater than or equal to a predetermined minimum number for combination and if a time interval between two successive second signals is less than an HF2 time; determining, by the processor, whether at least one HF2 signal is present in a predetermined time period that amounts to an accumulation length; defining, by the processor, time periods as an accumulation if a number of succeeding predetermined time periods is greater than or equal to an accumulation number; incrementing, by the processor, a WET1 accumulation counter by one if an accumulation is identified; resetting, by the processor, 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, by the processor, a waiting period after an accumulation value has been reached for the WET1 accumulation counter; terminating, by the processor, the waiting period and resetting the WET1 accumulation counter to zero if at least one first 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, by the processor, an arcing fault after the waiting period has elapsed, 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 a third signal is measured which has a duration longer than an LF2 limit length, wherein an interference signal occurring which has a frequency below a third frequency and a current intensity of the electrical current of the electrical circuit above an LF2 limit threshold is designated as the third signal, and wherein the parallel time period is ended if a measured third 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 third signal was measured for a second termination time span, and wherein the arcing fault is detected and/or reported: