Arc fault protected device

• US 6,567,250 B1
• Filed: 12/22/1999
• Issued: 05/20/2003
• Est. Priority Date: 02/19/1998
• Status: Expired due to Term

• Current Assignee: Square D Company (Schneider Electric SE)
• Original Assignee: Square D Company (Schneider Electric SE)
• Inventors: Wong, Kon B, Larson, Brett E., Dvorak, Robert F., Grattan, Brian, Haun, Andy A.
• Primary Examiner(s): Leja, Ronald W.
• Application Number:
  US09/469,869
• Time in Patent Office: 1,245 Days
• Field of Search: 361/42-50, 324/520, 324/522, 324/536, 324/613
• US Class Current: 361/42
• CPC Class Codes: H01H 2083/201 the other abnormal electrical condition being an arc fault
• CPC Class Codes: H01H 2300/03 Application domotique, e.g. for house automation, bus connected switches, sensors, loads or intelligent wiring
• CPC Class Codes: H01H 71/125 characterised by sensing elements, e.g. current transformers for differential protection H01H83/144
• CPC Class Codes: H02H 1/0015 Using arc detectors
• CPC Class Codes: H02H 1/06 Arrangements for supplying operative power power supply arrangements in general G05F, H02M
• CPC Class Codes: H02H 3/105 responsive to excess current and fault current to earth
• 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 3/44 responsive to the rate of change of electrical quantities
• CPC Class Codes: Y02B 70/30 Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
• CPC Class Codes: Y02B 90/20 Smart grids as enabling technology in buildings sector smart grids supporting the management or operation of end-user stationary applications in general, or like technologies with no associated climate change mitigation effect Y04S20/00
• CPC Class Codes: Y04S 20/14 Protecting elements, switches, relays or circuit breakers
• CPC Class Codes: Y04S 20/20 End-user application control systems

Abstract

An arcing fault protection assembly in an electrical device, and corresponding methods determine whether arcing is present in the device. The assembly comprises a sensor, a broadband noise circuit, and a controller. The sensor detects a current and develops a corresponding sensor signal. The broadband noise circuit determines the presence of broadband noise in the sensor signal and produces a corresponding output signal. The controller processes the sensor signal and the output signal in a predetermined fashion to determine whether an arcing fault is present. The sensor, broadband noise circuit, and controller are mounted to the device.

Claims

1. An arcing fault protection assembly, comprising:

a sensor which detects a current flowing at an electrical device and develops a corresponding sensor signal;

a broadband noise circuit which determines the presence of broadband noise in said sensor signal and produces a corresponding output signal; and

a controller which processes said sensor signal and said output signal in a predetermined fashion to determine current peaks and to determine, using said current peaks and the presence of broadband noise, whether an arcing fault is present;

wherein said sensor, said broadband noise circuit, and said controller are mounted to said electrical device;

where said device is selected from the following group;

an electrical extension cord, a junction box, a wall switch, a dimmer, a lighting fixture, a smoke detector, and an electrical appliance.

2. The arcing fault protection assembly of claim 1, wherein said controller produces a trip signal in response to a determination that an arcing fault is present.

3. The arcing fault protection assembly of claim 2, further comprising:

a tripping mechanism which stops the current from flowing at the electrical device in response to said trip signal.

4. The arcing fault protection assembly of claim 2, further comprising:

a ground fault sensor which detects a difference in current flow between a line conductor and a neutral conductor of the device to determine whether a ground fault is present, wherein said controller also produces said trip signal in response to a determination that a ground fault is present; and

a tripping mechanism which stops the current from flowing at the electrical device in response to said trip signal.

5. The arcing fault protection assembly of claim 1, further comprising a ground fault sensor which detects a difference in current flow between a line conductor and a neutral conductor of the device to determine whether a ground fault is present, wherein said controller produces a trip signal in response to a determination that a ground fault is present.

6. The arcing fault protection assembly of claim 5, further comprising:

a tripping mechanism which stops the current from flowing at the electrical device in response to said trip signal.

7. The arcing fault protection assembly of claim 1, wherein said broadband noise circuit is integrated into an application specific integrated circuit.

8. The arcing fault protection assembly of claim 1, wherein said arcing fault protection assembly uses chip-on-board technology.

9. The arcing fault protection assembly of claim 1, wherein said arcing fault protection assembly uses resistor-on-board technology.

10. The arcing fault protection assembly of claim 1, wherein said device comprises a connector of the electrical appliance.

11. A method of identifying, at an electrical device, whether arcing is present, comprising:

sensing a current at said device and developing a corresponding sensor signal,

determining the presence of broadband noise in said sensor signal and producing a corresponding output signal; and

processing said sensor signal and said output signal in a predetermined fashion to determine current peaks, and to determine, using said current peaks and the presence of broadband noise, whether an arcing fault is present,

wherein said determining and said processing also take place at said electrical device;

where said device is selected from the following group;

an electrical extension cord, a junction box, a wall switch, a dimmer, a lighting fixture, a smoke detector, and an appliance.

12. The method of claim 11, further comprising producing a trip signal in response to a determination that an arcing fault is present.

13. The method of claim 11, further comprising:

detecting a difference in current flow between a line conductor and a neutral conductor at the device to determine whether a ground fault is present; and

producing a trip signal in response to a determination that a ground fault is present.