Arc fault detector with circuit interrupter

• US 6,433,978 B1
• Filed: 07/10/2000
• Issued: 08/13/2002
• Est. Priority Date: 12/19/1997
• Status: Expired due to Term

• Current Assignee: Leviton Manufacturing Company Incorporated
• Original Assignee: Leviton Manufacturing Company Incorporated
• Inventors: Campolo, Steve, Bradley, Roger M., Rose, William J., Pearse, James N., Neiger, Benjamin B.
• Primary Examiner(s): Leja, Ronald W.
• Application Number:
  US09/612,904
• Time in Patent Office: 764 Days
• Field of Search: 361/42-50, 361/63, 361/78, 361/79, 361/88, 361/91.1, 361/93.1, 361/93.6, 361/94, 361/111, 702/58, 702/134, 702/FOR.103, 702/FOR.104, 702/FOR.105, 702/FOR.107, 324/508, 324/509, 324/512, 324/520, 324/525
• US Class Current: 361/42
• CPC Class Codes: H02H 1/0015 Using arc detectors
• CPC Class Codes: H02H 1/043 to inrush currents H02H1/046 takes precedence; differential protection of transformers H02H7/045
• CPC Class Codes: H02H 3/334 with means to produce an artificial unbalance for other protection or monitoring reasons or remote control H02H3/338 takes precedence

Abstract

An arc fault circuit interrupter (AFCI) device functions to provide protection from potentially dangerous arc faults. The arc fault detector can be used stand alone or in combination with circuit interrupting devices such as IDCIs and ALCIs. The AFCI device detects both AC line frequencies and high frequencies associated with arcing. Both average and instantaneous values of both AC line frequency and high frequency arcing signals are processed to generate an arc fault signal. The trip mechanism of the device trips on the occurrence of either an arc fault or a ground fault. The device allows the arc detector to differentiate between destructive high level arcing and low level arcing such as generated by typical household appliances and equipment. This serves to decrease the occurrence of false tripping. The device also includes a timer circuit, which permits the user to temporarily disable the arc detector, and includes communication means to permit the device to communicate the occurrence and location of the arc fault to a centralized monitoring station.

Claims

1. An arc fault detector capable of being electrically connected to an electrical wiring system comprising:

indicating means for providing an indicia representing the presence of at least one arc fault condition in the electrical wiring system;

trigger means for causing said indicating means to provide the indicia; and

arc fault detecting means for detecting in said electrical wiring system probable arc faults by using observed signal properties in a high frequency range and observed signal properties in an AC line frequency range, and for generating a trigger signal in response to the observed signal properties in at least one of said high frequency range and said AC line frequency range that activates said trigger means;

said arc fault detecting means uses peak and average signals in said high frequency range to detect arc faults occurring in said high frequency range.

2. An arc fault detector capable of being electrically connected to an electrical wiring system comprising:

indicating means for providing an indicia representing the presence of at least one arc fault condition in the electrical wiring system;

trigger means for causing said indicating means to provide the indicia; and

arc fault detecting means for detecting in said electrical wiring system probable arc faults by using observed signal properties in a high frequency range and observed signal properties in an AC line frequency range, and for generating a trigger signal in response to the observed signal properties in at least one of said high frequency range and said AC line frequency range that activates said trigger means;

wherein said arc fault detecting means uses peak and average signals in said AC line frequency range to detect arc faults occurring in said AC line frequency range.

3. An arc fault detector capable of being electrically connected to an electrical wiring system comprising:

indicating means for providing an indicia representing the presence of at least one arc fault condition in the electrical wiring system;

trigger means for causing said indicating means to provide the indicia; and

arc fault detecting means for detecting in said electrical wiring system probable arc faults by using observed signal properties in a high frequency range and observed signal properties in an AC line frequency range, and for generating a trigger signal in response to the observed signal properties in at least one of said high frequency range and said AC line frequency range that activates said trigger means, wherein the arc fault detecting means includes;

current measurement means for sensing a level of current flowing in said electrical wiring system;

high frequency circuit means for generating peak and average high frequency signals, wherein said peak high frequency signal corresponds to a peak level of high frequency current flowing in said electrical wiring system, and wherein said average high frequency signal corresponds to an average level of high frequency current flowing in said electrical wiring system;

AC line frequency circuit means for generating peak and average AC line frequency signals, wherein said peak AC line frequency signal corresponds to a peak level of AC line frequency current flowing in said electrical wiring system, and wherein said average AC line frequency signal corresponds to an average level of AC line frequency current flowing in said electrical wiring system; and

means for generating said trigger signal.

4. The device according to claim 3, wherein said means for generating said trigger signal generates said trigger signal when either said peak high frequency signal exceeds a predetermined threshold or said peak AC line frequency signal exceeds a predetermined threshold.

5. The device according to claim 3, wherein said means for generating said trigger signal generates said trigger signal when either said average high frequency signal exceeds a predetermined threshold or said average AC line frequency signal exceeds a predetermined threshold.

6. The device according to claim 3, wherein said means for generating said trigger signal generates said trigger signal after a time delay, said time delay being dependent upon a level of arcing detected or on a level of said sensed current.

7. The device according to claim 3, wherein said means for generating said trigger signal generates said trigger signal based on a plurality of arc fault trip levels which are dependent on a magnitude of said average AC line frequency current.

8. The device according to claim 3, wherein said means for generating said trigger signal generates said trigger signal based on a plurality of arc fault trip levels which are dependent on a level of said sensed current.

9. An arc fault detector capable of being electrically connected to an electrical wiring system comprising:

indicating means for providing an indicia representing the presence of at least one arc fault condition in the electrical wiring system;

trigger means for causing said indicating means to provide the indicia;

arc fault detecting means for detecting in said electrical wiring system probable arc faults by using observed signal properties in a high frequency range and observed signal properties in an AC line frequency range, and for generating a trigger signal in response to the observed signal properties in at least one of said high frequency range and said AC line frequency range that activates said trigger means; and

means for at least partially disabling said arc fault detecting means for a finite period of time to permit a user to use an electrical device exhibiting arcing, and for enabling said disabled arc fault detecting means after use of the electrical device exhibiting arcing has been discontinued.

10. An arc fault detector capable of being electrically connected to an electrical wiring system comprising:

indicating means for providing an indicia representing the presence of at least one arc fault condition in the electrical wiring system;

trigger means for causing said indicating means to provide the indicia;

arc fault detecting means for detecting in said electrical wiring system probable arc faults by using observed signal properties in a high frequency range and observed signal properties in an AC line frequency range, and for generating a trigger signal in response to the observed signal properties in at least one of said high frequency range and said AC line frequency range that activates said trigger means; and

means for receiving an external disable command and disabling at least a portion of said arc fault detecting means.

11. An arc fault detector capable of being electrically connected to an electrical wiring system comprising:

indicating means for providing an indicia representing the presence of at least one arc fault condition in the electrical wiring system;

trigger means for causing said indicating means to provide the indicia;

arc fault detecting means for detecting in said electrical wiring system probable arc faults by using observed signal properties in a high frequency range and observed signal properties in an AC line frequency range, and for generating a trigger signal in response to the observed signal properties in at least one of said high frequency range and said AC line frequency range that activates said trigger means; and

means for manually disabling and enabling at least a portion of said arc fault detecting means.

12. An arc fault detector capable of being electrically connected to an electrical wiring system comprising:

indicating means for providing an indicia representing the presence of at least one arc fault condition in the electrical wiring system;

trigger means for causing said indicating means to provide the indicia;

arc fault detecting means for detecting in said electrical wiring system probable arc faults by using observed signal properties in a high frequency range and observed signal properties in an AC line frequency range, and for generating a trigger signal in response to the observed signal properties in at least one of said high frequency range and said AC line frequency range that activates said trigger means; and

means for disabling at least a portion of said arc fault detecting means during daylight hours, and for enabling said disabled portion of said arc fault detecting means during night hours.

13. An arc fault detector capable of being electrically connected to an electrical wiring system comprising:

indicating means for providing an indicia representing the presence of at least one arc fault condition in the electrical wiring system;

trigger means for causing said indicating means to provide the indicia;

arc fault detecting means for detecting in said electrical wiring system probable arc faults by using observed signal properties in a high frequency range and observed signal properties in an AC line frequency range, and for generating a trigger signal in response to the observed signal properties in at least one of said high frequency range and said AC line frequency range that activates said trigger means; and

means for disabling and enabling at least a portion of said arc fault detecting means in accordance with signals received from a remote transmitter.

14. An arc fault detector capable of being electrically connected to an electrical wiring system comprising:

an indicator capable of providing an indicia representing the presence of at least one arc fault condition in the electrical wiring system;

a trigger circuit that causes the indicator to provide the indicia;

an arc fault detector operatively connected to the electrical wiring system to sense current flowing through the electrical wiring system, said arc fault detector/being capable of generating peak and average high frequency signals and peak and average AC line frequency signals from the sensed current, and capable of detecting arc faults in said AC high frequency and AC line frequency signals and generating a trigger signal in response to at least one of said peak high frequency signal, said average high frequency signal, said peak AC line frequency signal and said average AC line frequency signal, that activates said trigger circuit.

15. The device according to claim 14, wherein said arc fault detector comprises:

a high frequency circuit that receives the sensed current and generates said peak and average high frequency signals, wherein said peak high frequency signal corresponds to a peak level of high frequency current flowing through the device, and wherein said average high frequency signal corresponds to an average level of high frequency current flowing through the electrical wiring system; and

an AC line frequency circuit that receives the sensed current and generates said peak and average AC line frequency signals, wherein said peak AC line frequency signal corresponds to a peak level of AC line frequency current flowing through the electrical wiring system, and wherein said average AC line frequency signal corresponds to an average level of AC line frequency current flowing through the electrical wiring system.

16. The device according to claim 14, wherein said arc fault detector generates said trigger signal when either said peak high frequency signal exceeds a predetermined threshold or said peak AC line frequency signal exceeds a predetermined threshold.

17. The device according to claim 14, wherein said arc fault detector generates said trigger signal when either said average high frequency signal exceeds a predetermined threshold or said average AC line frequency signal exceeds a predetermined threshold.

18. The device according to claim 14, wherein said arc fault detector generates said trigger signal after a time delay, said time delay being dependent upon a level of arcing detected from said sensed current.

19. The device according to claim 14, wherein said arc fault detector generates said trigger signal based on a plurality of arc fault trip levels which are dependent on a magnitude of said average AC line frequency current.

20. The device according to claim 14, wherein said arc fault detector generates said trigger signal based on a plurality of arc fault trip levels which are dependent on said sensed current.

21. The device according to claim 14 further comprising means for simultaneously detecting peak and average magnitudes of said high frequency current and said AC line frequency current.

22. The circuit interrupting device according to claim 14 further comprising timer means for at least partially disabling said arc fault detector for a finite period of time to permit a user to use an electrical device exhibiting arcing, and for re-enabling said arc fault detector after use of the electrical device exhibiting arcing has been discontinued.

23. The circuit interrupting device according to claim 14 further comprising a fault detector capable of detecting a fault other than an arc fault, and for activating said trigger circuit when a fault other than an arc fault is detected.

24. The circuit interrupting device according to claim 23, wherein said fault detector comprises a ground fault circuit interrupter capable of detecting the occurrence of a ground fault and generating a trigger signal in response to the detection of the ground fault that activates said trigger circuit.

25. The circuit interrupting device according to claim 23, wherein said fault detector comprises an immersion detection circuit interrupter capable of detecting the occurrence of an immersion fault and generating a trigger signal in response to the detection of the immersion fault that activates said trigger circuit.

26. The circuit interrupting device according to claim 23, wherein said fault detector comprises an appliance leakage circuit interrupter capable of detecting the occurrence of an appliance leakage fault and generating a trigger signal in response to the detection of the appliance leakage fault that activates said trigger circuit.

27. An arc fault detector capable of being electrically connected to an electrical wiring system comprising:

an indicator capable of providing an indicia representing the presence of at least one arc fault condition in the electrical wiring system;

a trigger circuit that causes the indicator to provide the indicia; and

an arc fault detector capable of detecting in said electrical wiring system arc faults occurring in a high frequency range and arc faults occurring in an AC line frequency range, said arc fault detector responding to the detection of an arc fault in at least one of said high frequency range and said AC line frequency range by generating a trigger signal that causes said trigger circuit to activate said indicator, wherein said arc fault detector uses peak and average signals in said high frequency range to detect arc faults occurring in said high frequency range.

28. An arc fault detector capable of being electrically connected to an electrical wiring system comprising:

an indicator capable of providing an indicia representing the presence of at least one arc fault condition in the electrical wiring system;

a trigger circuit that causes the indicator to provide the indicia; and

an arc fault detector capable of detecting in said electrical wiring system arc faults occurring in a high frequency range and arc faults occurring in an AC line frequency range, said arc fault detector responding to the detection of an arc fault in at least one of said high frequency range and said AC line frequency range by generating a trigger signal that causes said trigger circuit to activate said indicator, wherein said arc fault detector uses peak and average signals in said AC line frequency range to detect arc faults occurring in said AC line frequency range.

29. An arc fault detector capable of being electrically connected to an electrical wiring system comprising:

an indicator capable of providing an indicia representing the presence of at least one arc fault condition in the electrical wiring system;

a trigger circuit that causes the indicator to provide the indicia; and

an arc fault detector capable of detecting in said electrical wiring system arc faults occurring in a high frequency range and arc faults occurring in an AC line frequency range, said arc fault detector responding to the detection of an arc fault in at least one of said high frequency range and said AC line frequency range by generating a trigger signal that causes said trigger circuit to activate said indicator, wherein the arc fault detector includes;

a current measurement circuit capable of sensing current flowing through the electrical wiring system;

a high frequency circuit capable of generating peak and average high frequency signals, wherein said peak high frequency signal corresponds to a peak level of high frequency current flowing through the electrical wiring system, and wherein said average high frequency signal corresponds to an average level of high frequency current flowing through the electrical wiring system;

an AC line frequency circuit capable of generating peak and average AC line frequency signals, wherein said peak AC line frequency signal corresponds to a peak level of AC line frequency current flowing through the electrical wiring system and wherein said average AC line frequency signal corresponds to an average level of AC line frequency current flowing through the electrical wiring system; and

a trigger generator circuit responsive to at least one of said peak high frequency signal, said average high frequency signal, said peak AC line frequency signal and said average AC line frequency signal, to generate said trigger signal.

30. The device according to claim 29, wherein said trigger generator circuit generates said trigger signal when either said peak high frequency signal exceeds a predetermined threshold or said peak AC line frequency signal exceeds a predetermined threshold.

31. The device according to claim 29, wherein said trigger generator circuit generates said trigger signal when either said average high frequency signal exceeds a predetermined threshold or said average AC line frequency signal exceeds a predetermined threshold.

32. The device according to claim 29, wherein said trigger generator circuit generates said trigger signal after a time delay, said time delay being dependent upon a level of arcing detected or on a level of said sensed current.

33. The device according to claim 29, wherein said trigger generator circuit generates said trigger signal based on a plurality of arc fault trip levels which are dependent on a magnitude of said average AC line frequency current.

34. The device according to claim 29, wherein said trigger generator circuit generates said trigger signal based on a plurality of arc fault trip levels which are dependent on a level of AC line frequency current.

35. An arc fault detector capable of being electrically connected to an electrical wiring system comprising:

an indicator capable of providing an indicia representing the presence of at least one arc fault condition in the electrical wiring system;

a trigger circuit that causes the indicator to provide the indicia;

an arc fault detector capable of detecting in said electrical wiring system arc faults occurring in a high frequency range and arc faults occurring in an AC line frequency range, said arc fault detector responding to the detection of an arc fault in at least one of said high frequency range and said AC line frequency range by generating a trigger signal that causes said trigger circuit to activate said indicator; and

an arc detection disabling circuit capable of at least partially disabling at least a portion of said arc fault detector for a finite period of time to permit a user to use an electrical device exhibiting arcing, and enabling said disabled portion of said arc fault detector after use of the electrical device exhibiting arcing has been discontinued.