Multifunction circuit breaker with single test button

• US 10,126,346 B2
• Filed: 11/22/2013
• Issued: 11/13/2018
• Est. Priority Date: 11/22/2013
• Status: Active Grant

• Current Assignee: Schneider Electric USA, Inc. (Schneider Electric SE)
• Original Assignee: Schneider Electric USA, Inc. (Schneider Electric SE)
• Inventors: Gass, Randall J., Drame, Issa V.
• Primary Examiner(s): Jackson, Stephen W
• Application Number:
  US15/035,750
• Publication Number:
  US 20160306002A1
• Time in Patent Office: 1,817 Days
• CPC Class Codes: G01R 31/50 Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections testing of sparking plugs H01T13/58
• CPC Class Codes: H01H 2083/201 the other abnormal electrical condition being an arc fault
• CPC Class Codes: H01H 83/04 with testing means for indicating the ability of the switch or relay to function properly
• CPC Class Codes: H02H 1/0015 Using arc detectors
• CPC Class Codes: H02H 3/16 responsive to fault current to earth, frame or mass with balanced or differential arrangement H02H3/26 ; monitoring earth connection H02H5/105
• CPC Class Codes: H02H 3/335 the main function being self testing of the device

Abstract

Method and system for implementing multiple user-initiated self-test sequences in a multifunction circuit breaker device uses a single test input to initiate both arc fault and ground fault testing while at the same time allowing the multifunction circuit breaker device to continue detecting actual arc faults and ground faults in near real time. Having one test input for multiple self-test sequences significantly reduces the number of mechanical and electrical components required by the circuit breaker device. The multifunction circuit breaker device also distinguishes between a simulated ground fault and an actual ground fault and avoids automatically tripping upon successful completion of the ground fault self-test sequence unless and until all self-test sequences have passed. In this way, users are not given a potentially incorrect indication that the multifunction circuit breaker device is working properly.

Claims

1. A system for providing user-initiated testing in a multifunction circuit breaker device, comprising:

a microcontroller configured to perform an arc fault self-test sequence and a ground fault self-test sequence in the multifunction circuit breaker device;

a supervisory circuit connected to the microcontroller and configured to simulate a ground fault for the ground fault self-test sequence; and

a test actuator connected to the supervisory circuit and configured to provide a single test input to the supervisory circuit when operated by a user, the single test input causing the supervisory circuit to simulate the ground fault for the ground fault self-test sequence;

wherein the microcontroller is configured to initiate the arc fault self-test sequence and the ground fault self-test sequence when the test actuator provides the single test input to the supervisory circuit, and to provide a pass indication to the user if both the arc fault self-test sequence and the ground fault self-test sequence pass;

wherein the microcontroller is further configured to provide no indication to the user if either the arc fault self-test sequence or the ground fault self-test sequence fails.

2. The system of claim 1, wherein the microcontroller is further configured to detect an actual arc fault and an actual ground fault in the multifunction circuit breaker device.

3. The system of claim 2, wherein the microcontroller is further configured to distinguish between the actual ground fault and a simulated ground fault in the multifunction circuit breaker device.

4. The system of claim 3, wherein the microcontroller is further configured to detect the actual ground fault using a first ground fault detection threshold and detect the simulated ground fault using a second ground fault detection threshold, the second ground fault detection threshold being lesser than the first ground fault detection threshold.

5. The system of claim 1, wherein the supervisory circuit is configured to provide a test start signal to the microcontroller when the test actuator provides the single test input to the supervisory circuit, the test start signal signaling the microcontroller to initiate the arc fault self-test sequence and the ground fault self-test sequence.

6. The system of claim 1, wherein the supervisory circuit is configured to be electrically connected to a power conductor on one of a line side or a load side when the user operates the test actuator.

19. The system of claim 1, wherein the supervisory circuit is configured to provide a self-test current in a ground current return path of the multifunction circuit breaker device to simulate the ground fault for the ground fault self-test sequence, the self-test current being lower than a normal ground fault current in the ground current return path of the multifunction circuit breaker device.

7. A multifunction circuit breaker device, comprising:

an arc fault sense circuit configured to sense actual arc faults;

a ground fault sense circuit configured to sense actual ground faults; and

a controller programmed to perform an arc fault self-test sequence and a ground fault self-test sequence and provide a pass indication to a user if both the arc fault self-test sequence and the ground fault self-test sequence pass, the controller connected to and configured to monitor the arc fault sense circuit and the ground fault sense circuit in near real time for detection of actual arc faults and actual ground faults during performance of the arc fault self-test sequence and the ground fault self-test sequence;

wherein the controller is further configured to immediately trip the circuit breaker in the multifunction circuit breaker device in response to the ground fault sense circuit sensing an actual ground fault and to delay tripping the circuit breaker in the multifunction circuit breaker device at least until both the arc fault self-test sequence and the ground fault self-test sequence pass if the ground fault sense circuit has not sensed an actual ground fault.

8. The multifunction circuit breaker device of claim 7, further comprising a self-test circuit connected to the controller and configured to provide a simulated ground fault current for the ground fault self-test sequence.

9. The multifunction circuit breaker device of claim 8, further comprising a test button connected to the self-test circuit and configured to provide a single test input to the self-test circuit when depressed by the user, the single test input causing the self-test circuit to provide the simulated ground fault current for the ground fault self-test sequence.

10. The multifunction circuit breaker device of claim 9, wherein the self-test circuit is configured to provide a start test signal to the controller upon the test button being depressed by the user, the start test signal signaling the controller to initiate the arc fault self-test sequence and the ground fault self-test sequence.

11. The multifunction circuit breaker device of claim 10, wherein the simulated ground fault current provided by the self-test circuit is approximately 3.5 mA RMS.

12. The multifunction circuit breaker device of claim 11, wherein the controller is programmed with a ground fault self-test sensitivity level corresponding to a 3.5 mA RMS test current during the ground fault self-test sequence.

13. The multifunction circuit breaker device of claim 7, further comprising a power supply module connected to and providing power to the controller, the power supply module electrically connected to either a line side or a load side of the multifunction circuit breaker.

14. The method of claim 7, wherein the controller is further configured to delay tripping the circuit breaker in the multifunction circuit breaker device until one or more internal controller diagnostic tests have passed.

20. The multifunction circuit breaker device of claim 8, wherein the self-test circuit is configured to provide a self-test current in a ground current return path of the multifunction circuit breaker device as the simulated ground fault current, the self-test current being lower than a normal ground fault current in the ground current return path of the multifunction circuit breaker device.

15. A method of performing arc fault and ground fault self-testing in a multifunction circuit breaker device, comprising:

monitoring for actual arc faults and actual ground faults in near real time in the multifunction circuit breaker device;

performing an arc fault self-test sequence and a ground fault self-test sequence in the multifunction circuit breaker device in response to receiving a single test input;

immediately tripping a circuit breaker in the multifunction circuit breaker device in response to an actual ground fault being detected; and

delaying tripping the circuit breaker in the multifunction circuit breaker device at least until both the arc fault self-test sequence and the ground fault self-test sequence pass if an actual ground fault is not detected;

wherein actual ground fault detection is performed using a first ground fault detection threshold and the ground fault self-test sequence is performed using a second ground fault detection threshold, the second ground fault detection threshold being lesser than the first ground fault detection threshold.

16. The method of claim 15, wherein the arc fault self-test sequence is performed before the ground fault self-test sequence is performed.

17. The method of claim 15, further comprising immediately tripping the circuit breaker in the multifunction circuit breaker device in response to an actual arc fault being detected.

18. The method of claim 15, further comprising generating the single test input in response to a user actuating a single test button in the multifunction circuit breaker device.

21. The method of claim 15, further comprising providing a self-test current in a ground current return path of the multifunction circuit breaker device to simulate a ground fault, the self-test current being lower than a normal ground fault current in the ground current return path of the multifunction circuit breaker device.

22. A system for providing user-initiated testing in a multifunction circuit breaker device, comprising:

a microcontroller configured to perform an arc fault self-test sequence and a ground fault self-test sequence in the multifunction circuit breaker device;

a supervisory circuit connected to the microcontroller and configured to provide a self-test current in a ground current return path of the multifunction circuit breaker device to simulate a ground fault for the ground fault self-test sequence, the self-test current being lower than a normal ground fault current in the ground current return path of the multifunction circuit breaker device; and

a test actuator connected to the supervisory circuit and configured to provide a single test input to the supervisory circuit when operated by a user, the single test input causing the supervisory circuit to simulate the ground fault for the ground fault self-test sequence;

wherein the microcontroller is configured to initiate the arc fault self-test sequence and the ground fault self-test sequence when the test actuator provides the single test input to the supervisory circuit, and to provide a pass indication to the user if both the arc fault self-test sequence and the ground fault self-test sequence pass.