Industrial arc fault circuit interrupter and method of detecting arcing conditions
First Claim
1. A circuit interrupter comprising:
- a number of poles, each of said number of poles comprising a pair of separable contacts;
an operating mechanism structured to open and close said pair of separable contacts for said number of poles; and
a trip mechanism cooperating with said operating mechanism to trip open said number of poles, said trip mechanism comprising a processor and further comprising for each of said number of poles;
a first current sensor structured to sense current flowing through said pair of separable contacts of a corresponding one of said number of poles,a number of second current sensors structured to sense a number of high frequency current signals from the current flowing through said pair of separable contacts of the corresponding one of said number of poles,a number of bandpass filters, each of said number of bandpass filters including an input receiving one of said number of high frequency current signals and an output,a number of peak detectors, each of said number of peak detectors including an input receiving the output of a corresponding one of said number of bandpass filters and an output, anda number of envelope detectors, each of said number of envelope detectors including an input receiving the output of a corresponding one of said number of bandpass filters and an output,wherein said processor is structured to;
count a count of occurrences of the output of each of said number of envelope detectors exceeding a first predetermined value,maintain a number of temporary values corresponding to the output of each of said number of peak detectors,determine an arc fault trip time as a function of the sensed current flowing through said pair of separable contacts for said number of poles,determine if the output of any of said number of peak detectors is greater than a second predetermined value, and, if so, responsively increase a corresponding one of said number of temporary values by a third predetermined value and, if not, decrease the corresponding one of said number of temporary values by a fourth predetermined value,determine if a predetermined function of said number of temporary values is greater than a fifth predetermined value, and, if so, for each of said number of peak detectors, add the corresponding one of said number of temporary values to an accumulator, and if not, decrease the accumulator by a sixth predetermined value, andcause said operating mechanism to trip open said number of poles if;
(a) a difference between said count corresponding to the current one of said half cycles having a polarity and said count corresponding to the immediately previous one of said half cycles having the same polarity is at least two, (b) said accumulator is greater than a seventh predetermined value, and (c) the arc fault trip time is reached.
2 Assignments
0 Petitions
Accused Products
Abstract
A method of detecting arcing conditions includes sensing current and HF signals therefrom; bandpass filtering the HF signals and providing filtered signals; detecting peak signals and envelopes from the filtered signals; counting occurrences of the envelopes exceeding a first value; maintaining temporary values corresponding to the peak signals; determining a trip time as a function of the current; determining if any peak signal is greater than a second value, and responsively increasing a temporary value and, otherwise, decreasing the temporary value; determining if a predetermined function of the temporary values is greater than a fifth value, and adding the temporary values to an accumulator, and otherwise, decreasing the accumulator; and tripping open the power circuit if: a difference between the occurrences of current and immediately previous half cycle having the same polarity is at least two, the accumulator is greater than a seventh value, and the trip time is reached.
-
Citations
22 Claims
-
1. A circuit interrupter comprising:
-
a number of poles, each of said number of poles comprising a pair of separable contacts; an operating mechanism structured to open and close said pair of separable contacts for said number of poles; and a trip mechanism cooperating with said operating mechanism to trip open said number of poles, said trip mechanism comprising a processor and further comprising for each of said number of poles; a first current sensor structured to sense current flowing through said pair of separable contacts of a corresponding one of said number of poles, a number of second current sensors structured to sense a number of high frequency current signals from the current flowing through said pair of separable contacts of the corresponding one of said number of poles, a number of bandpass filters, each of said number of bandpass filters including an input receiving one of said number of high frequency current signals and an output, a number of peak detectors, each of said number of peak detectors including an input receiving the output of a corresponding one of said number of bandpass filters and an output, and a number of envelope detectors, each of said number of envelope detectors including an input receiving the output of a corresponding one of said number of bandpass filters and an output, wherein said processor is structured to; count a count of occurrences of the output of each of said number of envelope detectors exceeding a first predetermined value, maintain a number of temporary values corresponding to the output of each of said number of peak detectors, determine an arc fault trip time as a function of the sensed current flowing through said pair of separable contacts for said number of poles, determine if the output of any of said number of peak detectors is greater than a second predetermined value, and, if so, responsively increase a corresponding one of said number of temporary values by a third predetermined value and, if not, decrease the corresponding one of said number of temporary values by a fourth predetermined value, determine if a predetermined function of said number of temporary values is greater than a fifth predetermined value, and, if so, for each of said number of peak detectors, add the corresponding one of said number of temporary values to an accumulator, and if not, decrease the accumulator by a sixth predetermined value, and cause said operating mechanism to trip open said number of poles if;
(a) a difference between said count corresponding to the current one of said half cycles having a polarity and said count corresponding to the immediately previous one of said half cycles having the same polarity is at least two, (b) said accumulator is greater than a seventh predetermined value, and (c) the arc fault trip time is reached. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
-
-
21. A method of detecting arcing conditions, said method comprising:
-
sensing current flowing through a power circuit; sensing a number of high frequency current signals from said current flowing; bandpass filtering each of said number of high frequency current signals and providing a number of corresponding bandpass filtered signals; detecting a number of peak signals from the number of corresponding bandpass filtered signals; detecting a number of envelopes from the number of corresponding bandpass filtered signals; counting a count of occurrences of the number of envelopes exceeding a first predetermined value; maintaining a number of temporary values corresponding to the number of peak signals; determining an arc fault trip time as a function of said sensed current flowing; determining if any of the number of peak signals is greater than a second predetermined value, and, if so, responsively increasing a corresponding one of said number of temporary values by a third predetermined value and, if not, decreasing the corresponding one of said number of temporary values by a fourth predetermined value; determining if a predetermined function of said number of temporary values is greater than a fifth predetermined value, and, if so, adding said number of temporary values to an accumulator, and if not, decreasing the accumulator by a sixth predetermined value; and tripping open said power circuit if;
(a) a difference between said count corresponding to the current one of said half cycles having a polarity and said count corresponding to the immediately previous one of said half cycles having the same polarity is at least two, (b) said accumulator is greater than a seventh predetermined value, and (c) the arc fault trip time is reached.
-
-
22. A circuit interrupter comprising:
-
separable contacts; an operating mechanism structured to open and close said separable contacts; and a trip mechanism cooperating with said operating mechanism to trip open said separable contacts, said trip mechanism comprising; a processor, a first current sensor structured to sense current flowing through said separable contacts, a number of second current sensors structured to sense a number of high frequency current signals from the current flowing through said separable contacts, a number of bandpass filters, each of said number of bandpass filters including an input receiving one of said number of high frequency current signals and an output, a number of peak detectors, each of said number of peak detectors including an input receiving the output of a corresponding one of said number of bandpass filters and an output, and a number of envelope detectors, each of said number of envelope detectors including an input receiving the output of a corresponding one of said number of bandpass filters and an output, wherein said processor is structured to; count a count of occurrences of the output of each of said number of envelope detectors exceeding a first predetermined value, maintain a number of temporary values corresponding to the output of each of said number of peak detectors, determine an arc fault trip time as a function of the sensed current flowing through said pair of separable contacts for said number of poles, determine if the output of any of said number of peak detectors is greater than a second predetermined value, and, if so, responsively increase a corresponding one of said number of temporary values by a third predetermined value and, if not, decrease the corresponding one of said number of temporary values by a fourth predetermined value, determine if a predetermined function of said number of temporary values is greater than a fifth predetermined value, and, if so, for each of said number of peak detectors, add the corresponding one of said number of temporary values to an accumulator, and if not, decrease the accumulator by a sixth predetermined value, and cause said operating mechanism to trip open said separable contacts if;
(a) a difference between said count corresponding to the current one of said half cycles having a polarity and said count corresponding to the immediately previous one of said half cycles having the same polarity is at least two, (b) said accumulator is greater than a seventh predetermined value, and (c) the arc fault trip time is reached.
-
Specification