# US 2021/0344185 A1 · Systems and methods for detecting and identifying arcing

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- Number: US 2021/0344185 A1
- Document ID: US20210344185A1
- Status: Published application
- Kind: A1
- Application number: 17/377,762
- Filed: 2021-07-16
- Published: 2021-11-04
- Earliest claimed: 2013-03-14
- Assignees: Hubbell Incorporated
- Applicants: Hubbell Incorporated
- Inventors: Gary Michael MILLER
- Web page: https://patentgrep.com/patent/US20210344185A1

## CPC

- H02H 1/0015: {Using arc detectors}
- G01R 31/14: Circuits therefor {, e.g. for generating test voltages, sensing circuits (G01R31/1209 - G01R31/1227 take precedence; for testing switches G01R31/327)}
- H02H: EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS (indicating or signalling undesired working conditions G01R, e.g. G01R31/00, G08B; locating faults along lines G01R31/08; emergency protective devices H01H)
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)

## Abstract

Systems and methods for detecting and identifying arcing are disclosed. A method of detecting arcing includes obtaining data indicative of voltage and data indicative of current, determining a waveform of a cycle of a primary load current according to the data indicative of current, determining at least one noise signal according to the determined waveform of a cycle of the primary load current and the data indicative of current, determining a probability density of the noise signal according to a time window, and comparing the probability density of the noise signal with at least one model probability density.

## Claims

### Claim 1

A method comprising:
determining a model probability density including
measuring a current in a conductor when inducing arcing in the conductor,
converting the current to a proportional voltage,
converting the current to a digitized current at a sample frequency,
converting the proportional voltage to a digitized voltage at the sample frequency,
determining a waveform of a cycle of a primary load current based on the digitized current,
determining at least one noise signal according to the determined waveform of the cycle of the primary load current and the digitized current,
setting a time window within a cycle of the digitized voltage by setting a start time and a stop time of a time interval based on voltage amplitude at the start time and the stop time being within a predetermined value of the peak voltage of the waveform of the cycle of the digitized voltage,
determining a probability density of the at least one noise signal according to the set time window, and
determining the model probability density at a voltage magnitude as a reference for a positive arc detection at the voltage magnitude;
detecting and identifying arcing including
converting a first current from a load to a first proportional voltage,
converting the first current to a first digitized current at a first sample frequency,
converting the first proportional voltage to a first digitized voltage at the first sample frequency,
determining a first waveform of a cycle of a primary load current based on the first digitized current,
determining at least one first noise signal according to the determined first waveform of the cycle of the primary load current and the first digitized current,
setting a first time window within a cycle of the first digitized voltage by setting a first start time and a first stop time of a first time interval based on first voltage amplitude at the first start time and the first stop time being within a first predetermined value of the peak voltage of the first waveform of the cycle of the first digitized voltage,
determining a first probability density of the at least one first noise signal according to the first set time window, and
comparing the probability density of the at least one first noise signal with the model probability density; and
generating an output indicative of a positive arc detection based on the comparing when the first time window is set based on values of the first digitized voltage indicative of the arc.

### Claim 2 (depends on 1)

The method of claim 1, wherein:
the converting of the first current from the load to the proportional first voltage comprises reducing the first voltage to an amplitude and a DC offset suitable for analog-to-digital conversion prior to the converting of the first current to the first digitized current and the converting of the first voltage to the first digitized voltage.

### Claim 3 (depends on 2)

The method of claim 2, further comprising removing high frequency noise from the first voltage.

### Claim 4 (depends on 2)

The method of claim 2, wherein the first sample frequency is equal to a multiple of the first voltage cycle frequency.

### Claim 5 (depends on 4)

The method of claim 4, further comprising determining the first voltage cycle frequency.

### Claim 6 (depends on 1)

The method of claim 1, further comprising determining one of the at least one first noise signal by subtracting the determined waveform of a cycle of the primary load current from one of at least one cycle of the first digitized current.

### Claim 7 (depends on 6)

The method of claim 6, further comprising adjusting the determined first waveform of at least a portion of a cycle of the primary load current according to one of the at least one first noise signals.

### Claim 8 (depends on 7)

The method of claim 7, wherein the adjusting of the determined waveform is by an error accumulator block.

### Claim 9 (depends on 7)

The method of claim 7, wherein the adjusting of the determined waveform comprises adding or subtracting a fraction of the one of the at least one first noise signal to or from the determined first waveform of a cycle of the primary load current.

### Claim 10 (depends on 1)

The method of claim 1, wherein the voltage amplitude at the start of the first time interval and the stop of the first time interval is within an upper portion of the peak voltage of the cycle of the first digitized voltage.

### Claim 11 (depends on 1)

The method of claim 1, wherein the determining of the first probability density of the at least one first noise signal comprises determining a histogram indicative of the at least one first noise signal,
wherein the histogram comprises a plurality of counts,
wherein each count is indicative of a number of amplitude bits of the at least one first signal within one of a plurality of amplitude intervals, and
wherein the amplitude bits are within the first time window of one of the at least one first noise signal.

### Claim 12 (depends on 11)

The method of claim 11, further comprising comparing the first probability density of the at least one first noise signal with the model probability density by at least one of:
determining a normalized histogram indicative of the at least one first noise signal by normalizing the histogram indicative of the at least one first noise signal; and
determining a positive arc detection if the normalized histogram indicative of the at least one first noise signal is similar to the model probability density according to a pattern matching algorithm.

### Claim 13 (depends on 12)

The method of claim 12, further comprising normalizing the histogram indicative of the at least one first noise signal by dividing each amplitude interval by a highest amplitude value in the plurality of amplitude intervals.

### Claim 14 (depends on 12)

The method of claim 12, further comprising determining the positive arc detection only if the histogram indicative of a highest amplitude value in a plurality of intervals in the histogram indicative of the at least one first noise signal is greater than a minimum amplitude value.

### Claim 15 (depends on 12)

The method of claim 12, wherein the model probability density is a normalized model probability density.

### Claim 16 (depends on 1)

The method of claim 1, wherein, if a normal periodic arcing noise is determined in one of the at least one first noise signals, the first probability density is determined by excluding the one of the at least one first noise signals.

### Claim 17 (depends on 1)

The method of claim 1, wherein the model probability density comprises at least one arc probability density.

### Claim 18 (depends on 1)

The method of claim 1, further comprising outputting an arc detect signal for tripping an arc fault circuit interrupter upon the positive arc detection.

### Claim 19 (depends on 1)

The method of claim 1, wherein the voltage amplitude at the start of the time interval and the stop of the time interval is within 10% of the peak voltage of the cycle of the digitized voltage.

### Claim 20 (depends on 1)

The method of claim 1 further comprising storing data indicative of the model probability density at the voltage magnitude in a non-transitory computer-readable medium as said reference for the positive arc detection at the voltage magnitude.