Upstream parallel arc fault outlet protection method

Patent metadata

Field	Value
Publication number	US-10084304-B2
Application number	US-201314900777-A
Country	US
Kind code	B2
Filing date	Jul 1, 2013
Priority date	Jul 1, 2013
Publication date	Sep 25, 2018
Grant date	Sep 25, 2018

Abstract

An arc fault circuit interrupter (AFCI) outlet is disclosed which detects and interrupts upstream parallel arc faults. The example AFCI outlet includes a switching element coupled between the line and neutral conductors at the outlet. The outlet also includes a voltage sensor and a current sensor. A parallel upstream arc fault is detected from a sensed voltage drop and no corresponding increase in current. On detecting the arc fault, the switching element is closed and current flows through the relatively lower resistance switching element interrupting power through the arc fault. The closed switching element results in an overcurrent condition causing an upstream conventional thermal-magnetic circuit breaker to trip.

First claim

What is claimed is:

1. An outlet to perform arc fault protection and detection, the outlet located downstream from a circuit breaker, the outlet comprising:
a switching element coupled between a line conductor and a neutral conductor having an open position and a closed position coupling the line conductor to the neutral conductor;
a voltage sensor coupled between the line conductor and the neutral conductor;
a current sensor coupled on the line conductor; and
a controller coupled to the switching element, the current sensor and the voltage sensor, the controller detecting a large voltage drop on the line conductor and no corresponding substantial increase in current on the line conductor indicative of a parallel arc fault between the outlet and the circuit breaker, and the controller closing the switching element in response to the detecting, wherein the closed position of the switching element creates a low resistance path for current flow sufficient to cause the circuit breaker to trip.

2. The outlet of claim 1 , where the switching element is a solid state transistor.

3. The outlet of claim 1 , wherein the controller is a microcontroller.

4. The outlet of claim 1 , wherein the controller detects a change in current on the line conductor to detect an arc fault on a second outlet coupled in series to the line conductor downstream of the outlet.

5. The outlet of claim 4 , further comprising a contact relay on the line conductor, the controller activating the contact relay to interrupt the line conductor when an arc fault is detected on the second outlet downstream of the outlet.

6. A method of determining parallel arc fault upstream of an outlet coupled to a circuit breaker via a line conductor and a neutral conductor, comprising:
detecting a high voltage drop between the line conductor and neutral conductor via a voltage sensor coupled between the line conductor and neutral conductor in the outlet;
detecting no substantial corresponding increase in current via a current detector on the line conductor at the outlet; and
closing a switching element coupled between the line conductor and the neutral conductor to create a low resistance current path between the line conductor and neutral conductor when the high voltage drop and no substantial increase in current is detected, wherein the closed position of the switching element creates a low resistance path for current flow sufficient to cause the circuit breaker to trip.

7. The method of claim 6 , where the switching element is a solid state transistor.

8. The method of claim 6 , wherein the switching element is closed via a controller.

9. The method of claim 6 , further comprising detecting a change in current on the line conductor to detect an arc fault on a second outlet coupled in series to the line conductor downstream of the outlet.

10. The method of claim 9 , further comprising activating a contact relay to interrupt the line conductor when an arc fault is detected on the second outlet downstream of the outlet.

11. A system to interrupt power when an upstream parallel arc fault is detected, the system comprising:
a line conductor;
a neutral conductor;
a circuit breaker coupled to the line conductor and the neutral conductor, the circuit breaker interrupting the flow of power when an overcurrent condition is detected;
an arc fault protection outlet coupled to the circuit breaker via the neutral and line conductors, the outlet including a switching element coupled between the neutral and line conductors, an outlet connector for connection to a load, a controller coupled to the switching element to control the switching element, a voltage sensor coupled between the neutral and line conductors and a current sensor coupled to the line conductor, the controller closing the switching element to electrically couple the neutral and line conductors when a high voltage drop is detected without an corresponding substantial increase in current thereby indicating the occurrence of an arc fault between the outlet and the circuit breaker, wherein closing the switching element creates a low resistance path for current flow sufficient to cause the circuit breaker to trip.

12. The system of claim 11 , where the switching element is a solid state transistor.

13. The system of claim 11 , wherein the controller is a microcontroller.

Assignees

• Schneider Electric Usa Inc

Inventors

• Beierschmitt Joseph
• Schroeder Jeremy

Classifications

• H02H3/207

  also responsive to under-voltage (window comparators for indication G01R19/165) · CPC title

• H02H3/023 Primary

  by short-circuiting · CPC title

• H02H1/0015

  Using arc detectors · CPC title

• H02H3/24 Primary

  responsive to undervoltage or no-voltage {(H02H3/207 takes precedence)} · CPC title

• H02H3/10

  additionally responsive to some other abnormal electrical conditions · CPC title