Circuit breaker health monitoring

Patent metadata

Field	Value
Publication number	US-10732223-B2
Application number	US-201816053601-A
Country	US
Kind code	B2
Filing date	Aug 2, 2018
Priority date	Sep 14, 2017
Publication date	Aug 4, 2020
Grant date	Aug 4, 2020

Abstract

Monitoring a health status of a current interruption device, such as a circuit breaker, is disclosed herein. For example, a device for monitoring a current interruption device may include a processor and a memory. The processor may execute instructions stored in the memory to cause the processor to monitor one or more current measurements of current from an electrical conductor that delivers electrical energy to a load. The processor may provide a signal indicating a health status of the current interruption device based at least in part on the one or more current measurements.

First claim

What is claimed is:

1. A monitoring device, comprising:
a memory; and
a processor communicatively coupled to the memory, wherein the processor is configured to execute instructions stored in the memory to cause the processor to:
obtain an amount of current on an electrical conductor that delivers electrical energy to a load;
obtain a signal indicating tripping of a circuit breaker, wherein the circuit breaker is electrically connected to the electrical conductor to control current flow on the electrical conductor;
determine a health status indicating whether a mechanical arc extinguishing feature of the circuit breaker is damaged for subsequent operation based at least in part on the amount of current interrupted by the circuit breaker during tripping of the circuit breaker; and
provide a signal indicating the health status of the circuit breaker.

2. The monitoring device of claim 1 , wherein the processor is configured to execute instructions stored in the memory to cause the processor to determine a maximum current of a three-phase power delivery system in determining the health status.

3. The monitoring device of claim 1 , wherein the processor is configured to execute instructions stored in the memory to cause the processor to determine that the circuit breaker is not healthy based at least in part on a comparison between the the amount of current and either a maximum measurable current multiplied by a factor or a minimum circuit breaker damage current.

4. The monitoring device of claim 1 , comprising a current transformer, wherein the processor is configured to execute instructions stored in the memory to cause the processor to provide the signal indicating that circuit breaker is not healthy upon detecting saturation of the current transformer by the current being delivered to the load.

5. The monitoring device of claim 1 , wherein the processor is configured to execute instructions stored in the memory to cause the processor to:
count a number of operations that the the amount of current exceeds a current threshold during the period of time in which the circuit breaker transitions to open; and
provide the signal indicating that the circuit breaker is not healthy when the number of operations exceeds a predetermined number of permitted operations.

6. The monitoring device of claim 1 , wherein the processor is configured to execute instructions stored in the memory to cause the processor to:
compare the amount of current to a predetermined value;
upon exceeding the predetermined value, determine an I 2 t value by squaring the the amount of current and integrating the squared current over a time period from when the predetermined value is exceeded to opening of the circuit breaker;
adding the I 2 t value to a sum of I 2 t values;
compare the sum of I 2 t values to a lifetime I 2 t threshold; and
upon exceeding the lifetime I 2 t threshold, provide the signal indicating that the circuit breaker is not healthy.

7. The monitoring device of claim 6 , wherein the processor is configured to execute instructions stored in the memory to cause the processor to reset the sum of I 2 t values upon replacing the circuit breaker with another circuit breaker.

8. The monitoring device of claim 1 , wherein the processor is configured to execute instructions stored in the memory to cause the processor to:
issue a trip command to trip the circuit breaker upon an occurrence of a predetermined condition; and
upon issuing the trip command, provide the signal indicating the health status of the circuit breaker.

9. A non-transitory, computer readable medium comprising instructions configured to be executed by a processor to communicate circuit breaker health, wherein the instructions are configured to cause the processor to:
obtain an amount of current through a an electrical conductor that delivers energy to a load;
obtain a signal indicating tripping of a circuit breaker, wherein the circuit breaker is electrically connected to the electrical conductor to control current flow on the electrical conductor;
determine a health status indicating whether a mechanical arc extinguishing feature of the circuit breaker is damaged for subsequent operation based at least in part on the amount of current interrupted by the circuit breaker during tripping of the circuit breaker; and
send a signal indicating the health status of the circuit breaker.

10. The non-transitory, computer-readable medium of claim 9 , wherein the instructions are configured to cause the processor to determine the health status based on a comparison of a predetermined threshold to a number of operations in which a current threshold is exceeded by the the amount of current.

11. The non-transitory, computer-readable medium of claim 10 , wherein the predetermined threshold is associated with a total number of operations that the circuit breaker is expected to withstand before being replaced.

12. The non-transitory, computer-readable medium of claim 9 , wherein the instructions are configured to cause the processor to determine the health status based on a comparison between the amount of current and a predetermined threshold associated with a maximum measurable current, a minimum circuit breaker damage current, or both.

13. The non-transitory, computer-readable medium of claim 9 , wherein the instructions are configured to cause the processor to determine the health status based on detection of saturation.

14. The non-transitory, computer-readable medium of claim 9 , wherein the instructions are configured to cause the processor to:
receive an input from a user indicating a setting of the circuit breaker; and
adjust a setting in determining the health status based on the input from the user.

15. A method, comprising:
obtaining, via sensor circuitry of an intelligent electronic device (IED), an amount of current on at least one conductor of a power system that delivers electrical energy to a load;
obtaining a signal indicating tripping of a circuit breaker, wherein the circuit breaker is electrically connected to the electrical conductor to control current flow on the electrical conductor;
determining, via a processor operatively coupled to a memory of the IED, a health status indicating whether a mechanical arc extinguishing feature of the circuit breaker is damaged for subsequent operation based at least in part on the amount of current interrupted by the circuit breaker during tripping of the circuit breaker; and
sending, via communication circuitry of the IED, a signal indicating the health status of the circuit breaker.

16. The method of claim 15 , comprising sending the signal indicating the health status to an indicator based on the health status.

17. The method of claim 16 , wherein the indicator comprises a display, a light emitting diode (LED) indicator, a human-to-machine (HMI) interface, a mechanical indicator, or any combination thereof, to indicate the health status to an operator.

18. The method of claim 15 , comprising sending, via the communication circuitry, the signal indicating the health status to another electronic device.

19. The method of claim 18 , comprising sending the signal via a serial communication channel, an ethernet communication channel, a wireless communication channel, or any combination thereof.

20. The method of claim 15 , comprising preventing a contactor from closing until the circuit breaker is replaced.

Assignees

• Schweitzer Engineering Lab Inc

Inventors

• Donolo Marcos A
• Manson Scott M

Classifications

• G01R31/3278 Primary

  of relays, solenoids or reed switches (measuring contact resistance G01R27/205; high voltage magnetic switches G01R31/3271, G01R31/333; testing electric windings G01R31/72; monitoring of fail safe circuits H01H47/002) · CPC title

• H01H2071/044

  Monitoring, detection or measuring systems to establish the end of life of the switching device, can also contain other on-line monitoring systems, e.g. for detecting mechanical failures · CPC title

• G01R31/3277 Primary

  of low voltage devices, e.g. domestic or industrial devices, such as motor protections, relays, rotation switches · CPC title

• H01H71/04

  Means for indicating condition of the switching device {(by means of an auxiliary contact H01H71/46)} · CPC title