Method and System For Detecting Arc Faults and Flashes Using Wavelets

• US 20140067291A1
• Filed: 08/27/2013
• Published: 03/06/2014
• Est. Priority Date: 08/27/2012
• Status: Active Grant

• Current Assignee: Texas A&M University System
• Original Assignee: Texas A&M University System
• Inventors: Balog, Robert S.
• Granted Patent: US 9,329,220 B2
• Time in Patent Office: Days
• US Class Current: 702/58
• CPC Class Codes: G01R 31/1227 of components, parts or materials G01R31/1209, G01R31/1218, G01R31/18 take precedence; circuits therefor G01R31/14; testing vessels of electrodes G01R31/16
• CPC Class Codes: G01R 31/52 Testing for short-circuits, leakage current or ground faults
• CPC Class Codes: H02H 1/0015 Using arc detectors
• CPC Class Codes: H02H 3/44 responsive to the rate of change of electrical quantities
• CPC Class Codes: H02H 3/46 responsive to frequency deviations
• CPC Class Codes: H02S 50/10 Testing of PV devices, e.g. of PV modules or single PV cells testing of semiconductor devices during manufacturing H01L22/00
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

Abstract

A method for detecting an arc event occurring in an electrical system includes sensing a voltage using a voltage sensing device coupled to a component of the electrical system, producing a signal waveform representative of the sensed voltage using the voltage sensing device, and sampling at a predetermined frequency the voltage signal waveform to generate a plurality of sample waveforms. The method further includes applying a wavelet transform to each sample waveform to decompose them into a predetermined number of detailed waveforms using a corresponding number of successive wavelet components, dividing each detailed waveform into a plurality of segments, analyzing the plurality of segments to detect a change in one or more of the properties of the corresponding detailed waveform, and determining an occurrence of the arc event based on the duration of the detected change of one or more of characteristics of the corresponding detailed waveform.

Claims

1. A computer-implemented method for detecting an arc event occurring in an electrical system, comprising:

sensing a voltage using a voltage sensing device coupled to a component of the electrical system, wherein the component need not be conductively directly connected to an occurrence location of the arc event in the electrical system;

producing a signal waveform representative of the sensed voltage using the voltage sensing device;

sampling at a predetermined frequency the voltage signal waveform to generate a plurality of sample waveforms;

applying a wavelet transform to each of the plurality of sample waveforms to decompose them into a predetermined number of waveforms using a corresponding number of successive wavelet components, wherein each of the successive wavelet components is a time-domain waveform that spans a predetermined range of frequencies;

dividing each waveform into a plurality of segments;

analyzing the plurality of segments to detect a change in one of the characteristics of the corresponding detailed waveform within the segments and/or between the segments; and

determining an occurrence of the arc event based on the detected change of one or more of the properties of the corresponding plurality of waveforms.

2. The computer-implemented method of claim 1, wherein analyzing the plurality of segments comprises:

comparing successive segments to detect the change in one of the properties of the corresponding decomposed detailed waveform.

3. The computer-implemented method of claim 1, further comprising determining a type of the arc event.

4. The computer-implemented method of claim 1, wherein the sensed voltage is an AC voltage or a DC voltage.

5. The computer-implemented method of claim 1, wherein each of the detailed waveforms represents a different level of the corresponding decomposed sample waveform, wherein the different level is characterized by a different band of frequencies comprising the original sensed signal.

6. The computer-implemented method of claim 1, wherein the one of the detected changed properties is one of a changed amplitude, a changed wavelength, a changed period (or frequency), a changed speed (wavelength/frequency), and a changed phase angle.

7. The computer-implemented method of claim 1, further comprising:

generating an indicator that an arc flash or fault has been detected.

8. The computer-implementation method of claim 1, further comprising:

a process in which the indicator is used to minimize any deleterious effect of the determined type of the arc event.

9. The computer-implemented method of claim 1, wherein the determined type of the arc event is an arc fault or an arc flash.

10. The computer-implemented method of claim 9, wherein the arc flash is identified based on a duration of the change of the one of the characteristics within a segment, from segment to segment, or from a first plurality of decomposed waveforms to a second plurality of decomposed waveforms.

11. A system for detecting an arc event occurring in an electrical system, comprising:

a voltage sensing device for sensing a voltage, wherein the voltage sensing device is coupled to a component of the electrical system, wherein the component is not conductively directly connected to an occurrence location of the arc event in the electrical system, wherein the voltage sensing device produces a signal waveform representative of the sensed voltage; and

a controller configured to;

sample at a predetermined frequency the voltage signal waveform to generate a plurality of sample waveforms;

apply a wavelet transform to each of the plurality of sample waveforms to decompose them into a predetermined number of detailed waveforms using a corresponding number of successive wavelet components, wherein each of the successive wavelet components is a time-domain waveform that covers a predetermined frequency band;

divide each detailed waveform into a plurality of segments;

analyze the plurality of segments to detect a change in one of the properties of the corresponding detailed waveform within the segments and/or between the segments; and

determine an occurrence of the arc event based on the detected change of one of the properties of the corresponding detailed waveform.

12. The system of claim 11, wherein in order to analyze the plurality of segments the controller compares successive segments to detect the change in one of the properties of the corresponding decomposed detailed waveform.

13. The system of claim 11, wherein each of the detailed waveforms represents a different level of the corresponding decomposed sample waveform, wherein the different level is characterized by a different time and frequency resolution.

14. The system of claim 11, wherein the one of the detected changed properties is one or a combination of a changed amplitude, a changed wavelength, a changed period (or frequency), a changed speed (wavelength/frequency), and a changed phase angle.

15. The system of claim 11, wherein the controller is further configured to:

generate an operational decision to minimize any effect of the determined type of the arc event.

16. The system of claim 11, wherein the controller is further configured to:

hasten an extinction of the arc event.

17. The system of claim 15, wherein the determined type of the arc event is an arc fault or an arc flash.

18. The system of claim 17, wherein the arc flash is identified based on an arc flash is identified based on a duration of the change of the one of the characteristics within a segment, from segment to segment, or from a first plurality of decomposed waveforms to a second plurality of decomposed waveforms.

19. A computing system, comprising:

a processing unit and a memory unit for storing instructions that are operable, when executed by the processing unit, to perform a method for detecting an arc event occurring in an electrical system, the method comprising;

sensing a voltage using a voltage sensing device coupled to a component of the electrical system, wherein the component is not conductively directly connected to an occurrence location of the arc event in the electrical system;

producing a signal waveform representative of the sensed voltage using the voltage sensing device;

sampling at a predetermined frequency the voltage signal waveform to generate a plurality of sample waveforms;

applying a wavelet transform to each of the plurality of sample waveforms to decompose them into a predetermined number of detailed waveforms using a corresponding number of successive wavelet components, wherein each of the successive wavelet components is a time-domain waveform that covers a predetermined frequency band;

partitioning each detailed waveform into a plurality of segments;

analyzing the plurality of segments to detect a change in one of the properties of the corresponding detailed waveform within the segments and/or between the segments; and

determining an occurrence of the arc event based on the detected change of one of the properties of the corresponding detailed waveform.

20. The computing system of claim 19, further comprising:

generating an operational decision to minimize any effect of the determined type of the arc event or hasten the extinction of the arcing event.

21. The computing system of claim 19, wherein the determined type of the arc event is an arc fault or an arc flash.

22. The computing system of claim 21, wherein the arc flash is identified based on an duration and characteristics of the plurality of decomposed waveforms of the sensed voltage or current.