Method for AC arc fault detection using multidimensional energy points

Patent metadata

Field	Value
Publication number	US-10509067-B2
Application number	US-201715642409-A
Country	US
Kind code	B2
Filing date	Jul 6, 2017
Priority date	Jul 6, 2017
Publication date	Dec 17, 2019
Grant date	Dec 17, 2019

Abstract

A method for detecting an arc fault in AC circuits. The method includes monitoring disturbances in an AC voltage signal by analyzing multi-dimensional energy points. A voltage signal is captured and the zero-crossing, minimum peak, and maximum peak are identified. Arcing signatures between the maximum and minimum peaks of the captured AC voltage signal are analyzed to detect an arc fault.

First claim

Having described the invention, the following is claimed:

1. A method for detecting arc faults in an AC circuit using arc fault detection circuitry communicatively coupled to a data acquisition device, the data acquisition device including a voltage measurement device, comprising:
(a) measuring via the data acquisition device an AC voltage signal of the AC circuit to obtain one cycle of the AC voltage signal, and providing the measured AC voltage signal to the arc fault detection circuitry;
(b) obtaining by the arc fault detection circuitry a left-hand energy summation value and a right-hand energy summation value from the measured AC voltage signal, wherein the left-hand energy summation value is determined by summing left-hand energy values left of a zero-crossing and the right-hand energy summation value is determined by summing right-hand energy values right of the zero-crossing;
(c) obtaining by the arc fault detection circuitry a differential left-hand energy summation value and a differential right-hand energy summation value, wherein the differential left-hand energy summation value and differential right-hand energy summation value respectively indicate changes in the left-hand energy summation value and the right-hand energy summation value;
(d) obtaining by the arc fault detection circuitry a total energy summation value for use in generating stable arc boundaries, wherein the total energy summation value is a sum of the left-hand energy summation value and the right-hand energy summation value;
(e) determining by the arc fault detection circuitry whether both the differential left-hand energy summation value and the differential right-hand energy summation value are simultaneously inside their respective transient arc boundaries, wherein if both the differential left-hand energy summation value and the differential right-hand energy summation value are simultaneously inside their respective transient arc boundaries, then setting a potential arc flag;
(f) determining by the arc fault detection circuitry whether both the left-hand energy summation value and the right-hand energy summation value are simultaneously inside a stable arc boundary, wherein if both the left-hand energy summation value and the right-hand energy summation value are simultaneously inside the stable arc boundary, then setting the potential arc flag;
(g) detecting by the arc fault detection circuitry an arc fault if a predetermined number of consecutive potential arc flags are set; and
(h) repeating steps (a) through (g) a plurality of times to monitor for arc faults.

2. The method according to claim 1 , wherein the step of obtaining the plurality of left-hand energy summation values and the plurality of right-hand energy summation values includes:
determining maximum and minimum peaks in the one cycle of the AC voltage signal;
determining the zero-crossing between the maximum and minimum peaks of the one cycle of the AC voltage signal;
applying a band pass filter to the one cycle of the AC voltage signal;
truncating the one cycle of the AC voltage signal to a window between the maximum and the minimum peaks;
squaring voltage values of the one cycle of the AC voltage signal to obtain squared voltage values indicative of energy values;
applying minimum and maximum energy thresholds to the energy values; and
summing the energy values to the left of the zero-crossing within the minimum and maximum energy thresholds to determine the left-hand energy summation value and summing the energy values to the right of the zero-crossing within the minimum and maximum energy thresholds to determine the right-hand energy summation value.

3. The method according to claim 1 , wherein the stable arc boundary is determined using an arithmetic average of a group of consecutive left-hand and right-hand energy summation values.

4. The method according to claim 1 , wherein the transient arc detection boundary for the differential left-hand energy summation value is determined using an average of a group of consecutive differential left-hand energy summation values.

5. The method according to claim 1 , wherein the transient arc detection boundary for the differential right-hand energy summation value is determined using an average of a group of consecutive differential right-hand energy summation values.

6. The method according to claim 1 , wherein the predetermined number of consecutive potential arc flags is at least 5.

7. The method according to claim 1 , wherein said transient arc boundaries and said stable arc boundary are re-calculated periodically.

Assignees

• Mersen Usa Newburyport Ma Llc
• Univ Northeastern

Inventors

• Kim Jonathan C
• Lehman Bradley M
• Neacsu Dorin Octavian
• Ball Roy

Classifications

• H02H1/0015

  Using arc detectors · CPC title

• G01R31/1272 Primary

  of cable, line or wire insulation, e.g. using partial discharge measurements (locating faults in cables G01R31/083) · CPC title

• G01R31/02 Primary

  Physics · mapped topic

• G01R31/025

  Physics · mapped topic

• G01R31/52 Primary

  Testing for short-circuits, leakage current or ground faults · CPC title