DETECTION OF ELECTRIC DISCHARGES THAT PRECEDE FIRES IN ELECTRICAL WIRING

• US 20190293701A1
• Filed: 03/20/2019
• Published: 09/26/2019
• Est. Priority Date: 03/20/2018
• Status: Active Grant

• Current Assignee: Whisker Labs, Inc. (Earth Networks Incorporated)
• Original Assignee: Whisker Labs, Inc. (Earth Networks Incorporated)
• Inventors: Marshall, Robert S., Sloop, Christopher Dale, Heckman, Stan, Bixler, Donnie, Hoppmann, Eric
• Granted Patent: US 10,641,806 B2
• Time in Patent Office: Days
• CPC Class Codes: G01R 27/28 Measuring attenuation, gain, phase shift or derived characteristics of electric four pole networks, i.e. two-port networks; Measuring transient response in line transmission systems H04B3/46
• CPC Class Codes: G01R 31/001 Measuring interference from external sources to, or emission from, the device under test, e.g. EMC, EMI, EMP or ESD testing measuring electromagnetic fields G01R29/08; circuits for generating HV pulses in dielectric strength testing G01R31/14
• CPC Class Codes: G01R 31/085 in power transmission or distribution lines, e.g. overhead
• CPC Class Codes: G01R 31/086 in power transmission or distribution networks, i.e. with interconnected conductors
• CPC Class Codes: H02H 1/0015 Using arc detectors

Abstract

Described herein are methods and systems for detecting electrical discharges that precede electrical fires in electrical wiring. One or more sensor devices coupled to a circuit detect one or more signal waveforms generated by electrical activity on the circuit. The sensor devices identify one or more transient signals within the one or more signal waveforms, and generate one or more transient characteristics based upon the identified transient signals. A server communicably coupled to the sensor devices receives the one or more transient characteristics. The server analyzes the one or more transient characteristics to identify one or more electrical discharge indications. The server generates one or more alert signals when one or more electrical discharge indications are identified.

Claims

1. A system for detecting electrical discharges that precede electrical fires in electrical wiring, the system comprising:

one or more sensor devices coupled to a circuit, each sensor device configured to

detect one or more signal waveforms generated by electrical activity on the circuit;

identify one or more transient signals within the one or more signal waveforms; and

generate one or more transient characteristics based upon the identified transient signals;

a server computing device communicably coupled to the one or more sensor devices, the server computing device configured to;

receive the one or more transient characteristics from each sensor device;

analyze the transient characteristics to identify one or more electrical discharge indications; and

generate one or more alert signals when one or more electrical discharge indications are identified.

2. The system of claim 1, wherein the one or more signal waveforms comprise a full voltage cycle waveform.

3. The system of claim 2, wherein the one or more sensor devices sample the full voltage cycle waveform at a frequency in a range between 10 MHz and 100 MHz.

4. The system of claim 3, wherein identifying one or more transient signals within the one or more signal waveforms comprises:

a) dividing the samples of the full voltage cycle waveform into a plurality of bins;

b) determining a mean value and a maximum value for each of the plurality of bins;

c) determining a difference between the mean value and the maximum value;

d) repeating steps a)-c) for each of a plurality of other samples of the full voltage cycle waveform to determine an accumulated maximum value for each bin across all of the samples; and

e) determining a derivative of each accumulated maximum value across the plurality of bins.

5. The system of claim 4, wherein generating one or more transient characteristics based upon the identified transient signals comprises:

determining an average transient amplitude over a voltage cycle of the full voltage cycle waveform; and

determining an average transient amplitude for a plurality of phase sections within the voltage cycle.

6. The system of claim 5, wherein analyzing the transient characteristics to identify one or more electrical discharge indications comprises:

determining a ratio of average peak transients in one or more of the phase sections near a maximum voltage to average peak transients near a zero crossing of the voltage cycle; and

identifying the average peak transients in one or more of the phase sections near a maximum voltage as electrical discharge indications, when the ratio is above a predetermined threshold.

7. The system of claim 6, wherein generating one or more alert signals when one or more electrical discharge indications are identified comprises:

determining a count of the identified electrical discharge indications occurred within a predetermined amount of time; and

generating an alert signal based upon the count of the identified electrical discharge indications.

8. The system of claim 3, wherein identifying one or more transient signals within the one or more signal waveforms comprises:

a) determining a derivative of the samples of the full voltage signal waveform across a full voltage cycle;

b) dividing the samples of the full voltage cycle waveform into a plurality of bins;

c) determining a maximum value for each of the plurality of bins;

d) repeating steps a)-c) for each of a plurality of other samples of the full voltage cycle waveform to determine an accumulated maximum value for each bin across all of the samples; and

e) determining a derivative of each accumulated maximum value across the plurality of bins.

9. The system of claim 8, wherein generating one or more transient characteristics based upon the identified transient signals comprises:

determining an average transient amplitude over a voltage cycle of the full voltage cycle waveform; and

determining an average transient amplitude for a plurality of phase sections within the voltage cycle.

10. The system of claim 9, wherein analyzing the transient characteristics to identify one or more electrical discharge indications comprises:

determining a ratio of average peak transients in one or more of the phase sections near a maximum voltage to average peak transients near a zero crossing of the voltage cycle; and

identifying the average peak transients in one or more of the phase sections near a maximum voltage as electrical discharge indications, when the ratio is above a predetermined threshold.

11. The system of claim 10, wherein generating one or more alert signals when one or more electrical discharge indications are identified comprises:

determining a count of the identified electrical discharge indications occurred within a predetermined amount of time; and

generating an alert signal based upon the count of the identified electrical discharge indications.

12. The system of claim 2, wherein the one or more sensor devices sample the full voltage cycle waveform at 80 MHz upon detecting that the one or more signal waveforms have reached a threshold value.

13. The system of claim 12, wherein identifying one or more transient signals within the one or more signal waveforms comprises:

identifying one or more samples of the full voltage cycle waveform that exceed a threshold value; and

storing the identified one or more samples.

14. The system of claim 13, wherein generating one or more transient characteristics based upon the identified transient signals comprises, for each identified sample:

determining a count of peaks in the identified sample;

determining a rise time of the peaks in the identified sample;

determining a pulse width of the identified sample; and

determining an integral of the identified sample.

15. The system of claim 14, wherein analyzing the transient characteristics to identify one or more electrical discharge indications comprises categorizing the identified sample as an electrical discharge indication when the count of peaks in the identified sample is above a predetermined threshold and when the rise time of the peaks in the identified sample is above a predetermined threshold.

16. The system of claim 15, wherein generating one or more alert signals when one or more electrical discharge indications are identified comprises:

determining a count of the identified electrical discharge indications occurred within a predetermined amount of time; and

generating an alert signal based upon the count of the identified electrical discharge indications.

17. The system of claim 1, wherein the one or more sensor devices identify one or more transient signals within the one or more signal waveforms and generate one or more transient characteristics based upon the identified transient signals using a transient detection profile stored in a memory module of the sensor device.

18. The system of claim 17, wherein the server computing device generates an updated transient detection profile based upon transient characteristics received from one or more of the sensor devices and transmits the updated transient detection profile to each of the one or more sensor devices.

19. The system of claim 18, wherein the one or more sensor devices apply the updated transient detection profile to identify subsequent transient signals within the one or more signal waveforms and generate the one or more transient characteristics.

20. The system of claim 1, wherein the server computing device transmits the one or more alert signals to a remote computing device.

21. The system of claim 1, wherein the server computing device transmits the one or more alert signals to at least one of the one or more sensor devices.

22. The system of claim 21, wherein the at least one of the one or more sensor devices activates a visual indicator upon receiving at least one of the one or more alert signals.

23. The system of claim 22, wherein the visual indicator is a light emitting diode (LED) component of the at least one of the one or more sensor devices.

24. The system of claim 1, wherein the server computing device uses one or more machine learning algorithms to analyze the transient characteristics to identify one or more electrical discharge indications.