Abstract: A string includes direct current electrical generating modules electrically connected in series to form a first end and a remote second end. A power line is electrically connected to one DC EGM at the first end. A return line is electrically connected to another DC EGM at the remote second end. A first string protector is in the power line of the string, and a second SP is in the return line of the string at the remote second end. One of the first and second SPs includes a number of an over current protector, an arc fault protector, a reverse current protector and a ground fault protector. The other one of the first and second SPs includes a number of an over current protector, an arc fault protector, a reverse current protector, a ground fault protector, and a remotely controlled switch in series with the power or return lines.

Abstract: A protection apparatus is for a direct current electrical generating apparatus. The protection apparatus includes a first terminal; a second terminal; a third terminal; a fourth terminal; at least one current sensor structured to sense current flowing between the first and second terminals or between the third and fourth terminals; a voltage sensor structured to sense a voltage between the first terminal and the third terminal; at least one switch structured to interrupt the current flowing between the first and second terminals or between the third and fourth terminals; and a processor cooperating with the at least one current sensor, the voltage sensor and the at least one switch, and being structured to provide feed forward fault protection for the direct current electrical generating apparatus.

Abstract: A direct current arc fault circuit interrupter includes separable contacts and a trip circuit to trip open the contacts. The trip circuit includes a number of alternating current sensors structured to sense a current flowing through the separable contacts, a number of filter circuits cooperating with the AC current sensors to output a number of AC signals, a number of peak detectors cooperating with the filter circuits to output a number of peak current signals, and a processor cooperating with at least the peak detectors. The processor inputs the number of peak current signals as a plurality of peak current signals or inputs the number of peak current signals and determines the plurality of peak current signals. The processor also determines if the peak current signals exceed corresponding predetermined thresholds for a predetermined time, and responsively causes the contacts to trip open.

Abstract: A protection apparatus is for a direct current electrical generating apparatus. The protection apparatus includes a first terminal; a second terminal; a third terminal; a fourth terminal; at least one current sensor structured to sense current flowing between the first and second terminals or between the third and fourth terminals; a voltage sensor structured to sense a voltage between the first terminal and the third terminal; at least one switch structured to interrupt the current flowing between the first and second terminals or between the third and fourth terminals; and a processor cooperating with the at least one current sensor, the voltage sensor and the at least one switch, and being structured to provide feed forward fault protection for the direct current electrical generating apparatus.

Abstract: An electrical switching apparatus comprises: a first terminal; a second terminal; separable contacts electrically connected between the first terminal and the second terminal; an operating mechanism structured to open and close the separable contacts; and an arc fault trip circuit cooperating with the operating mechanism and structured to trip open the separable contacts responsive to an arc fault condition. An inductor is electrically connected in series between the first terminal and the second terminal. A capacitor includes a first lead electrically connected between the inductor and the second terminal, and a second lead electrically connected to a ground or neutral conductor. The inductor and the capacitor are structured to cooperate with a power circuit impedance downstream of the second terminal to form a filter trap circuit.

Abstract: A direct current arc fault circuit interrupter includes separable contacts and a trip circuit to trip open the contacts. The trip circuit includes a number of alternating current sensors structured to sense a current flowing through the separable contacts, a number of filter circuits cooperating with the AC current sensors to output a number of AC signals, a number of peak detectors cooperating with the filter circuits to output a number of peak current signals, and a processor cooperating with at least the peak detectors. The processor inputs the number of peak current signals as a plurality of peak current signals or inputs the number of peak current signals and determines the plurality of peak current signals. The processor also determines if the peak current signals exceed corresponding predetermined thresholds for a predetermined time, and responsively causes the contacts to trip open.

Abstract: A string includes direct current electrical generating modules electrically connected in series to form a first end and a remote second end. A power line is electrically connected to one DC EGM at the first end. A return line is electrically connected to another DC EGM at the remote second end. A first string protector is in the power line of the string, and a second SP is in the return line of the string at the remote second end. One of the first and second SPs includes a number of an over current protector, an arc fault protector, a reverse current protector and a ground fault protector. The other one of the first and second SPs includes a number of an over current protector, an arc fault protector, a reverse current protector, a ground fault protector, and a remotely controlled switch in series with the power or return lines.

Abstract: An electrical switching apparatus comprises: a first terminal; a second terminal; separable contacts electrically connected between the first terminal and the second terminal; an operating mechanism structured to open and close the separable contacts; and an arc fault trip circuit cooperating with the operating mechanism and structured to trip open the separable contacts responsive to an arc fault condition. An inductor is electrically connected in series between the first terminal and the second terminal. A capacitor includes a first lead electrically connected between the inductor and the second terminal, and a second lead electrically connected to a ground or neutral conductor. The inductor and the capacitor are structured to cooperate with a power circuit impedance downstream of the second terminal to form a filter trap circuit.

Abstract: A circuit breaker includes a first lug and second and third acoustic lugs electrically connected to a power circuit. Separable contacts are electrically connected in series between the first lug and the second acoustic lug. An operating mechanism opens and closes the separable contacts. A first acoustic sensor is coupled to the second acoustic lug and senses a first acoustic signal from the second acoustic lug. A second acoustic sensor is coupled to the third acoustic lug and senses a second acoustic signal from the third acoustic lug. The first and second acoustic signals are operatively associated with a power circuit fault. A current sensor senses a current flowing between the first and second lugs. A circuit inputs the sensed acoustic signals and the sensed current and detects and distinguishes a parallel arc fault or a series arc fault from the sensed acoustic signals and the sensed current.

Abstract: An arc fault circuit interrupter includes line and load terminals, separable contacts, a current sensor sensing current flowing between the terminals and associated with one type of load, and a first arc fault detection circuit generating a first trip signal responsive to the sensed current. A second arc fault detection circuit collects a plurality of sensed current samples for a current line cycle and also for a previous line cycle, determines a total current value from a peak current of the current line cycle samples, employs the total current value and some of the samples to determine the type of load, and generates a second trip signal responsive to the sensed current and the determined type of load. A trip circuit generates a third trip signal responsive to the first and second trip signals. An operating mechanism opens the contacts responsive to the third signal.

Abstract: An arc fault detector analyzes patterns in a sequence of counts of interval to interval increases or decreases in integrated current for patterns characteristic of arc faults. In AC systems, the interval can be a full cycle or in an alternative embodiment, the changes in integrated current for positive and negative half cycles are separately determined and then interleaved before the change counts are calculated. The count sequence is reset when patterns characteristic of phenomena other than an arc fault are detected to avoid nuisance trips.

Abstract: A circuit breaker for locating an arc fault for a protected circuit includes separable contacts interrupting the protected circuit and an arc fault detector determining an arc fault in the protected circuit. An analog to digital converter circuit measures a value of peak arc current at the arc fault detector. Another analog to digital converter circuit provides a peak line-to-neutral voltage. A memory provides an arc voltage operatively associated with the value of peak current. A microprocessor determines a distance from the arc fault detector to the arc fault from the value of peak arc current, a wire resistance per unit length or a wire conductance per unit length, the peak line-to-neutral voltage and the arc voltage.

Abstract: A circuit breaker detects a fault, such as an arc fault or glowing contact, of a power circuit. The circuit breaker includes a first lug and a second acoustic lug adapted to be electrically connected to the power circuit. Separable contacts are electrically connected in series between the first lug and the second acoustic lug. An operating mechanism is adapted to open and close the separable contacts. An acoustic sensor is coupled to the second acoustic lug. The acoustic sensor is adapted to sense an acoustic signal from the second acoustic lug. The acoustic signal is operatively associated with the fault of the power circuit. A circuit inputs the sensed acoustic signal and is adapted to detect the fault therefrom.

Abstract: A detection module and remote load voltage sensor determine a location of a parallel arc for a power circuit between a power source and a load in real time. The detection module provides a value of voltage from the power source. A current sensor measures a value of current flowing in the power circuit to or from the power source. The remote load voltage sensor measures a value of voltage at the load. A microprocessor determines the parallel arc location from the value of voltage from the power source, the value of current, the value of voltage at the load, and a wire resistance or conductance per unit length of the power circuit. In one case, connector resistance is accounted for. In another case, the load voltage is encoded at a predetermined frequency using a switched precision resistor near the load, thereby providing a power line carrier type communication.

Abstract: A circuit breaker for locating an arc fault for a protected circuit includes separable contacts interrupting the protected circuit and an arc fault detector determining an arc fault in the protected circuit. An analog to digital converter circuit measures a value of peak arc current at the arc fault detector. Another analog to digital converter circuit provides a peak line-to-neutral voltage. A memory provides an arc voltage operatively associated with the value of peak current. A microprocessor determines a distance from the arc fault detector to the arc fault from the value of peak arc current, a wire resistance per unit length or a wire conductance per unit length, the peak line-to-neutral voltage and the arc voltage.

Abstract: Arcing faults in dc electric power systems are detected by apparatus which responds to a predetermined drop either in voltage across, or current drawn by, a dc load. The voltage and current drops can be measured values or scaled to the source voltage. In another arrangement, the load current is interrupted momentarily when a step decrease in current is detected. If the dc current does not return, within a predetermined margin, to the decreased value before interruption, arcing is indicated. In a third embodiment, drift of the load current following detection of a step decrease, either upward toward a short or downward toward an open circuit, is taken as an indication of arcing.

Abstract: Tripping of a circuit breaker by an arc fault detector is blocked by a disable circuit upon detection of a transient associated with cold turn-on of an incandescent bulb powered by a dimmer. The peak value of pulses generated by the bandpass filter of the arc detector in response to step increases in the ac current is decayed approximately exponentially. The amplitude of each pulse is compared with upper and lower percentage limits of the decaying peak value. If the amplitudes of the pulses remain below the upper threshold for about 3 to 4 half cycles and exceed the lower threshold each half cycle, a dimmer transient is identified and logic is set to block generation of a false arc signal.

Abstract: Electrical equipment (14) is safeguarded from damage due to parallel arc faults by a circuit that provides several levels of protection. A semiconductor switch (18) and a current sensor (24) are placed in series with the electrical equipment (14). When the current to the equipment exceeds a first threshold for a predefined period of time, the semiconductor switch (18) is rendered non-conductive until the circuit is specifically reset. When the current to the equipment exceeds a greater second threshold, a pulsed signal alternately places the semiconductor switch (18) in conductive and non-conductive states so that the average current applied to the equipment (14) is within an acceptable level. The pulses are measured to determine whether a parallel arc fault has occurred. When the measured pulses (74) are within a predetermined range, a parallel arc fault is declared and the semiconductor switch (18) is rendered non-conductive.

Abstract: Tripping of a circuit breaker by an arc fault detector is blocked by a disable circuit upon detection of a transient associated with cold turn-on of an incandescent bulb powered by a dimmer. The peak value of pulses generated by the bandpass filter of the arc detector in response to step increases in the ac current is decayed approximately exponentially. The amplitude of each pulse is compared with upper and lower percentage limits of the decaying peak value. If the amplitudes of the pulses remain below the upper threshold for about 3 to 4 half cycles and exceed the lower threshold each half cycle, a dimmer transient is identified and logic is set to block generation of a false arc signal.

Abstract: Arcing in dc electrical systems subject to cyclic disturbances is detected by a current sensor, and a bandpass filter sensitive to arcing noise, which filters the sensor current. The absolute value of the bandpass filtered signal is integrated over repetitive intervals in a resettable analog integrator. A low cost microprocessor samples and resets the analog integrator at a frequency below the pass band and generates a time attenuated accumulation of the samples that produces an arcing signal if it reaches a predetermined limit. To improve nuisance immunity, the sensed dc current is compared in a high speed comparator to the average sensed dc current, and only samples taken by the microprocessor during a predetermined time period after the sensed dc current exceeds the average sensed dc current in a predetermined manner are accumulated. The average sensed dc current is also used by the microprocessor to provide overload protection.