Circuit protection device with grounded neutral half cycle self test
First Claim
1. A protection device for use in an AC power distribution system, the device being configured to be coupled between an AC power distribution system and at least one load, the device comprising:
- a test circuit configured to generate at least one simulated fault signal during a first predetermined half-cycle of said AC power, the at least one simulated fault signal including a grounded neutral simulated fault signal;
a detector circuit coupled to the test circuit, the detector being configured to generate a detection signal in response to the at least one simulated fault signal;
a fault checking mechanism coupled to the detector, the fault checking mechanism being configured to generate an internal fault signal if the detection signal is not generated within a predetermined period of time; and
a response mechanism coupled to the fault checking mechanism, the response mechanism being configured to generate a response if the internal fault signal is generated.
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Abstract
The present invention is directed to a circuit and method for self-testing a protection device for use in an AC power distribution system. The device is configured to be coupled between an AC power distribution system and at least one load. The method includes the step of introducing a simulated ground neutral fault during a first predetermined half cycle half cycle of the AC power. An attempt is made to detect the introduced simulated grounded neutral fault during the first predetermined half cycle half cycle. A fault condition is signaled if the introduced simulated grounded neutral fault is not detected within a predetermined period of time.
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Citations
39 Claims
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1. A protection device for use in an AC power distribution system, the device being configured to be coupled between an AC power distribution system and at least one load, the device comprising:
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a test circuit configured to generate at least one simulated fault signal during a first predetermined half-cycle of said AC power, the at least one simulated fault signal including a grounded neutral simulated fault signal; a detector circuit coupled to the test circuit, the detector being configured to generate a detection signal in response to the at least one simulated fault signal; a fault checking mechanism coupled to the detector, the fault checking mechanism being configured to generate an internal fault signal if the detection signal is not generated within a predetermined period of time; and a response mechanism coupled to the fault checking mechanism, the response mechanism being configured to generate a response if the internal fault signal is generated. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A self testing protection device for use in an AC power distribution system, the device being configured to be coupled between an AC power distribution system and at least one load, the device comprising:
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a simulated grounded neutral test circuit configured to transmit a simulated grounded neutral fault signal during a first predetermined half cycle of AC power; a ground fault sensor coupled to the simulated grounded neutral test circuit, the ground fault sensor being configured to sense a ground fault condition and the simulated grounded neutral fault signal and provide a sensor signal in response thereto; a first detector coupled to the ground fault sensor, the first detector being configured to generate a first detection signal in response to the sensor signal; a resonant tank coupled to the first detector, the resonant tank being configured to generate a resonating signal in response to the first detection signal, the resonating signal indicating that protection device components are operational; and a second detector coupled to the resonant tank, the second detector being configured to generate an internal fault signal if the resonating signal is not detected by the second detector within a predetermined period of time. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38)
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39. A method for self-testing a protection device for use in an AC power distribution system, the device being configured to be coupled between an AC power distribution system and at least one load, the method comprising:
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introducing a simulated ground neutral fault during a first predetermined half cycle of the AC power; attempting to detect the introduced simulated grounded neutral fault during the first predetermined half cycle; and signaling a fault condition if the introduced simulated grounded neutral fault is not detected within a predetermined period of time.
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Specification