Circuit interrupt device fault duration monitor

Patent metadata

Field	Value
Publication number	US-2025036505-A1
Application number	US-202318227232-A
Country	US
Kind code	A1
Filing date	Jul 27, 2023
Priority date	Jul 27, 2023
Publication date	Jan 30, 2025
Grant date	—

Abstract

Methods/systems for monitoring fault duration in circuit interrupt devices perform edge detection using a second time derivative of a current or voltage waveform. The second derivative reveals peaks that may be used to establish starting and ending times for the fault duration. In some embodiments, the second derivatives are derived only for portions of the waveform within time windows that enclose the fault duration starting and ending times, respectively. The above arrangement provides a consistent way of determining durations of transitory events, such as durations of faults, and the like, that does not rely on waveform zero-crossings. The duration determinations may be implemented locally within a device, and/or the device may acquire and transfer underlying waveform data to an external system for the duration determinations. Data from multiple devices may be collected over time for analysis and modeling to provide remote support and monitoring of local devices via digital twins.

First claim

I/We claim:

1 . A circuit interrupt protective device, comprising:
a central processing unit (CPU); a sense circuit connected to the CPU and configured to sense a current or a voltage waveform in the circuit interrupt protective device, the current or voltage waveform originating from an AC mains; an analog-to-digital converter (ADC) coupled to the CPU and configured to acquire the current or voltage waveform sensed by the sensor circuit; a fault detection module coupled to the ADC and configured to receive the current or voltage waveform acquired by the ADC, the fault detection module operable to detect a fault event based on the current or voltage waveform; and a fault duration module coupled to the ADC and configured to receive the current or voltage waveform acquired by the ADC, the fault duration module operable to obtain a duration of the fault event based on the current or voltage waveform; wherein the duration of the fault event is obtained by computing a second derivative for a portion of the current or voltage waveform, finding a local maximum or local minimum for the portion of the current or voltage waveform, and setting the local maximum or the local minimum as a starting time or an ending time for the duration of the fault event.

2 . The circuit interrupt protective device according to claim 1 , wherein the second derivative is computed locally by the fault duration module.

3 . The circuit interrupt protective device according to claim 1 , wherein the second derivative is computed on an external system using a digital twin of the circuit interrupt protective device.

4 . The circuit interrupt protective device according to claim 1 , wherein the portion of the current or voltage waveform is a window defined based on a transient amplitude of the current or voltage waveform that exceeds a predefined threshold.

5 . The circuit interrupt protective device according to claim 4 , wherein the window contains a predefined subset of data points representing the current or voltage waveform, the predefined subset of data points including the transient amplitude that exceeds the predefined threshold.

6 . The circuit interrupt protective device according to claim 1 , wherein an error is declared if the duration of the fault event exceeds a specified maximum.

7 . The circuit interrupt protective device according to claim 7 , wherein the CPU is operable to automatically take one or more actions in the circuit interrupt protective device if an error is declared.

8 . A method of determining a duration of a fault event in a circuit interrupt protective device, the method comprising:
sensing, at a sensor circuit of the circuit interrupt protective device, a current or a voltage waveform in the circuit interrupt protective device, the current or voltage waveform originating from an AC mains; acquiring, at an analog-to-digital converter (ADC) of the circuit interrupt protective device, the current or voltage waveform sensed by the sensor circuit; receiving, at a fault detection module of the circuit interrupt protective device, the current or voltage waveform acquired by the ADC, the fault detection module operable to detect a fault event based on the current or voltage waveform; and receiving, at a fault duration module of the circuit interrupt protective device, the current or voltage waveform acquired by the ADC, the fault duration module operable to obtain a duration of the fault event based on the current or voltage waveform; wherein the duration of the fault event is obtained by computing a second derivative for a portion of the current or voltage waveform, finding a local maximum or a local minimum for the portion of the current or voltage waveform, and setting the local maximum or the local minimum as a starting time or an ending time for the duration of the fault event.

9 . The method according to claim 8 , wherein the second derivative is computed locally by the circuit interrupt protective device.

10 . The method according to claim 8 , wherein the second derivative is computed on an external system using a digital twin of the circuit interrupt protective device.

11 . The method according to claim 8 , further comprising defining the portion of the current or voltage waveform as a window based on a transient amplitude of the current or voltage waveform that exceeds a predefined threshold.

12 . The method according to claim 11 , wherein the window contains a predefined subset of data points representing the current or voltage waveform, the predefined subset of data points including the transient amplitude that exceeds the predefined threshold.

13 . The method according to claim 8 , further comprising declaring an error in the circuit interrupt protective device if the duration of the fault event exceeds a specified maximum.

14 . The method according to claim 13 , further comprising automatically taking one or more actions in the circuit interrupt protective device if an error is declared.

15 . A non-transitory computer-readable medium having computer-readable instructions stored thereon for determining a duration of a fault event in a circuit interrupt protective device, the computer-readable instructions, when executed by a processor, cause the processor to perform a process that:
senses, at a sensor circuit of the circuit interrupt protective device, a current or a voltage waveform in the circuit interrupt protective device, the current or voltage waveform originating from an AC mains; acquires, at an analog-to-digital converter (ADC) of the circuit interrupt protective device, the current or voltage waveform sensed by the sensor circuit; receives, at a fault detection module of the circuit interrupt protective device, the current or voltage waveform acquired by the ADC, the fault detection module operable to detect a fault event based on the current or voltage waveform; and receives, at a fault duration module of the circuit interrupt protective device, the current or voltage waveform acquired by the ADC, the fault duration module operable to obtain a duration of the fault event based on the current or voltage waveform; wherein the duration of the fault event is obtained by computing a second derivative for a portion of the current or voltage waveform, finding a local maximum or a local minimum for the portion of the current or voltage waveform, and setting the local maximum or the local minimum as a starting time or an ending time for the duration of the fault event.

16 . The non-transitory computer-readable medium according to claim 15 , wherein the computer-readable instructions cause the second derivative to be computed locally on the circuit interrupt protective device.

17 . The non-transitory computer-readable medium according to claim 15 , wherein the computer-readable instructions cause the second derivative to be computed on an external system using a digital twin of the circuit interrupt protective device.

18 . The non-transitory computer-readable medium according to claim 15 , wherein the computer-readable instructions define the portion of the current or voltage waveform as a window based on a transient amplitude of the current or voltage waveform that exceeds a predefined threshold.

19 . The non-transitory computer-readable medium according to claim 18 , wherein the window contains a predefined subset of data points representing the current or voltage waveform, the predefined subset of data points including the transient amplitude that exceeds the predefined threshold.

Assignees

• Schneider Electric Usa Inc

Inventors

• Fischels Collin Richard
• Melecio Ramirez Juan Ignacio
• Rendon Hernandez Adrian Abdala
• Riehl Kenneth

Classifications

• G06F30/20

  Design optimisation, verification or simulation (optimisation, verification or simulation of circuit designs G06F30/30) · CPC title

• H02H1/0092

  concerning the data processing means, e.g. expert systems, neural networks · CPC title

• H02H1/0007

  concerning the detecting means (in general G01R or other subclasses of G01; reed switches H01H71/2445) · CPC title

• G01R31/52

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

• G01R31/327

  Testing of circuit interrupters, switches or circuit-breakers · CPC title