Arcing fault detector testing and demonstration system

• US 5,834,940 A
• Filed: 09/24/1996
• Issued: 11/10/1998
• Est. Priority Date: 09/24/1996
• Status: Expired due to Term

• Current Assignee: Square D Company (Schneider Electric SE)
• Original Assignee: Square D Company (Schneider Electric SE)
• Inventors: Brooks, Stanley J., Reneau, Charles E.
• Primary Examiner(s): Karlsen, Ernest F.
• Assistant Examiner(s): Solis, Jose M.
• Application Number:
  US08/719,972
• Time in Patent Office: 777 Days
• Field of Search: 361/42, 324/424, 324/418, 324/509, 324/423, 324/536
• US Class Current: 324/424
• CPC Class Codes: G01R 31/1272 of cable, line or wire insulation, e.g. using partial discharge measurements locating faults in cables G01R31/083
• CPC Class Codes: G01R 31/3277 of low voltage devices, e.g. domestic or industrial devices, such as motor protections, relays, rotation switches
• CPC Class Codes: G01R 31/52 Testing for short-circuits, leakage current or ground faults
• CPC Class Codes: H02H 1/0015 Using arc detectors

Abstract

An apparatus for demonstrating and testing the operation of an arcing fault detector. The apparatus comprises an electrical circuit including line and neutral conductors connected between a power source and a load. A selector switch is movable between a first position and a second position in order to selectively route load current across either an arcing fault detector or standard circuit breaker. A pair of electrodes is positioned between said selector switch and the load for producing an arcing condition on the line conductor. The arcing fault detector preferably comprises a sensor for monitoring the rate of change of electrical current on the line conductor and producing a rate-of-change signal, a means for producing a pulse each time the rate-of-change signal exceeds a selected threshold, a means for filtering the rate-of-change signal and/or pulse to eliminate signals or pulses representing changes in electrical current outside a selected frequency range, a means for producing a count signal representing a number of unfiltered pulses occurring within a selected time interval, and a means for generating a trip signal in response to the count signal exceeding a trip threshold level indicative of an arcing fault condition.

Claims

1. A system for demonstrating or testing the operation of an arcing fault detector in comparison to a standard circuit breaker, the system comprising:

a power circuit including a power source, a load, and a standard circuit breaker;

an arcing fault detector and associated line interrupter in parallel with said standard circuit breaker;

pair of electrodes connected in series with said load for producing an arcing condition; and

a selector switch for selectively connecting said pair of electrodes to one of said standard circuit breaker and said arcing fault detector and associated line interrupter.

2. The system of claim 1 wherein the standard circuit breaker, the arcing fault detector and the pair of electrodes are physically remote from an electrical distribution panelboard so that demonstration and testing of the arcing fault detector in comparison to the circuit breaker may be accomplished remote from the panelboard.

3. The demonstration and testing system of claim 2 further comprising an ammeter connected between said load and said pair of electrodes for monitoring levels of load current supplied to said pair of electrodes.

4. The demonstration and testing system of claim 3 further comprising an indicator device for indicating when power is being supplied to said demonstration and testing system.

5. The demonstration and testing system of claim 4 wherein the indicator device further indicates when power to said demonstration and testing system has been interrupted by said line interrupter.

6. The demonstration and testing system of claim 2 wherein one of said pair of electrodes is comprised of copper and another one of said pair of electrodes is comprised of carbon.

7. The demonstration and testing system of claim 6 wherein a first one of said pair of electrodes is in a stationary position and a second one of said pair of electrodes is movable to a variable position relative to the first electrode.

8. The demonstration and testing system of claim 6 further comprising a linear positioning device for positioning the second electrode relative to the position of the first electrode.

9. The demonstration and testing system of claim 8 wherein the standard circuit breaker, arcing fault detector, pair of electrodes and selector switch are enclosable within a portable case.

23. The demonstration and testing system of claim 4 further comprising a bypass switch movable between an open position and a closed position, said load current being provided to said pair of electrodes in response to said bypass switch being in said open position, said load current bypassing said pair of electrodes in response to said bypass switch being in said closed position.

10. A method of demonstrating or testing the operation of an arcing fault detector in comparison to a standard circuit breaker, said method comprising the steps of:

supplying a load current to a pair of electrodes;

producing a simulated arcing fault condition between said pair of electrodes;

selectively connecting said pair of electrodes to an arcing fault detector and to a standard circuit breaker;

observing that the standard circuit breaker does not trip in response to the simulated arcing fault condition; and

observing that the arcing fault detector trips in response to the simulated arcing fault condition.

21. The method of claim 10 wherein the standard circuit breaker, the arcing fault detector and the pair of electrodes are physically remote from an electrical distribution panelboard so that demonstration and testing of the arcing fault detector in comparison to the circuit breaker may be accomplished remote from the panelboard.

11. A system for demonstrating or testing the operation of an arcing fault detector in comparison to a standard circuit breaker, the system comprising:

an electrical circuit including line and neutral conductors connected between a power source and a load, said line conductor carrying an electrical signal between said power source and said load;

a selector switch positioned between the power source and the load and movable between a first position and a second position;

an arcing fault detector and associated line interrupter connected to said line conductor between said power source and said selector switch, said electrical signal being provided to said arcing fault detector in response to said selector switch being in said first position, said electrical signal not being provided to said arcing fault detector in response to said selector switch being in said second position;

a standard circuit breaker in parallel to said arcing fault detector and connected to said line conductor between said power source and said selector switch, said electrical signal being provided to said standard circuit breaker in response to said selector switch being in said second position, said electrical signal not being provided to said standard circuit breaker in response to said selector switch being in said first position; and

a pair of electrodes positioned between said selector switch and said load for producing an arcing condition on said line conductor.

12. The system of claim 11 wherein the standard circuit breaker, the arcing fault detector and the pair of electrodes are physically remote from an electrical distribution panelboard so that demonstration and testing of the arcing fault detector in comparison to the circuit breaker may be accomplished remote from the panelboard.

13. The demonstration and testing system of claim 12 wherein a first one of said pair of electrodes is comprised of copper and a second one of said pair of electrodes is comprised of carbon.

14. The demonstration and testing system of claim 12 wherein a first one of said pair of electrodes is in a stationary position and a second one of said pair of electrodes is movable to a variable position relative to the first electrode, said demonstration and testing system including a linear positioning device for positioning the second electrode relative to the position of the first electrode.

22. The demonstration and testing system of claim 12 further comprising:

an ammeter connected in series with said load for monitoring levels of load current supplied to said pair of electrodes;

an indicator device for indicating when power is being supplied to said demonstration and testing system and for indicating when power to said demonstration and testing system has been interrupted by said line interrupter; and

a bypass switch movable between an open position and a closed position, said load current being provided to said pair of electrodes in response to said bypass switch being in said open position, said load current bypassing said pair of electrodes in response to said bypass switch being in said closed position.

15. A system for demonstrating or testing the operation of an arcing fault detector in comparison to a standard circuit breaker, the system comprising:

an electrical circuit including line and neutral conductors connected between a power source and a load, said line conductor carrying an electrical signal between said power source and said load;

a pair of electrodes positioned between said power source and said load for producing an arcing condition on said line conductor;

a line interrupter for interrupting the electrical signal between said power source and said load in response to receiving a trip signal;

an arcing fault detector connected to said line conductor between said power source and said pair of electrodes, said arcing fault detector producing said trip signal upon detection of an arcing fault on said line conductor;

a standard circuit breaker connected in series to said arcing fault detector on said line conductor between said power source and said pair of electrodes, said standard circuit breaker producing said trip signal upon detection of an overcurrent condition on said line conductor; and

indicator means for indicating which one of said arcing fault detector and said standard circuit breaker produced said trip signal in response to said line interrupter interrupting the electrical signal between said power source and said load.

16. The system of claim 15 wherein the standard circuit breaker, the arcing fault detector and the pair of electrodes are physically remote from an electrical distribution panelboard so that demonstration and testing of the arcing fault detector in comparison to the circuit breaker may be accomplished remote from the panelboard.

17. The demonstration and testing system of claim 16 further comprising:

an ammeter connected in series with said load for monitoring levels of load current supplied to said pair of electrodes;

an indicator device for indicating when power is being supplied to said demonstration and testing system; and

a bypass switch movable between an open position and a closed position, said load current being provided to said pair of electrodes in response to said bypass switch being in said open position, said load current bypassing said pair of electrodes in response to said bypass switch being in said closed position.

18. The demonstration and testing system of claim 17 wherein the indicator device further indicates when power to said demonstration and testing system has been interrupted.

19. The demonstration and testing system of claim 16 wherein a first one of said pair of electrodes is comprised of copper and a second one of said pair of electrodes is comprised of carbon.

20. The demonstration and testing system of claim 16 wherein the first electrode is in a stationary position and the second electrode is movable to a variable position relative to the first electrode, said demonstration and testing system including a linear positioning device for measuring the position of the second electrode relative to the position of the first electrode.