TH45409A - Arc defect measurement in the arc zone. - Google Patents

Abstract

DC60 (23/05/49) Several methods can be used for arc protection in the arc zone to detect series arc faults and/or arc faults in power dividers, electrical components, and/or circuits. Differential current detectors or DI/DT detectors can be used to detect arcs in power dividers, while differential voltage detectors or zero-sequence voltage detectors are used to detect series arcs. Differential phase current detection schemes can be used for both power divider and series arcs. Series arcs can also be detected using voltage drop systems or line power loss systems. Arc detection at line junctions can be monitored directly. Ground fault detectors can be combined with one or more of these systems for ground fault detection in the protected circuits. Two or more of the above systems or detectors can be combined for arc monitoring and arc detection. Several methods can be used for arc protection in the arc zone to detect faults. To detect series and/or parallel arc faults in electrical components and/or circuits, derivative current detectors or DI/DT detectors can be used. Parallel arc detection can be achieved by measuring derivative voltages, while zero-sequence voltages are measured for series arc detection. Derivative phase current measurement schemes can be used for both parallel and series arc detection. Series arc detection can also be achieved using voltage drop systems or line power loss systems. Arc detection can be monitored directly, and earth fault detection can be integrated with one or more of these systems for earth fault detection in protected circuits. Two or more of the above systems or detectors can be acquired for arc monitoring and detection.

Claims (25)

1. Arc fault detection system in the arc zone for detection in a defined area of an electrical circuit. It consists of a voltage summator for summarizing the voltages of all phases of the aforementioned circuit, both on the source and load sides of the zone, and a comparator for comparing the sum of the voltages at one end of the load and source sides and the sum of the voltages at the other end of each phase, and for generating a differential signal corresponding to any difference between them. 2. The system of claim 1 also includes an arc fault detection device that responds to the magnitude of the aforementioned differential signal above a predetermined threshold value for generating a cutoff signal. 3. System of Claim 1 where the aforementioned voltage combining device consists of several series resistors, each resistor having its first end connected to one end of the load and source ends in the aforementioned region of each phase of the aforementioned circuit, and where the aforementioned comparator has one input connected to the end opposite to the first aforementioned end of the aforementioned series resistors connected to the source end of each phase, and a second input connected to one end opposite to the first aforementioned end of the aforementioned series resistors connected to the load end of each phase. 4. The system of claim number 1 also includes compensating devices for providing compensation for circuits where the neutral conductor has a much higher impedance than the phase conductor, or where the neutral conductor divides a large current from other branches. 5. The system of claim number 1 also includes a derivative current detector. 6. Arc Fault Detection System in the Arc Zone: This system detects arc faults in a defined zone of an electrical circuit. It consists of a differential phase current detector with identically insulated conductors arranged parallel to each other. For each zone of each phase to be protected by the aforementioned differential phase current detector, a protected zone is defined as a section of the parallel conductors between two points where the two conductors are connected. A transformer current detector is inductively connected to each pair of parallel conductors. The aforementioned transformer current detector and the conductors are configured and arranged in such a way that the current drawn in the transformer current detector from one conductor to another conductor in the transformer current detector to produce a differential current output. 7. The system of claims under clause 6 also includes a derivative current arc detector. 8. The system of claims under clause 5 or 7 whereby the aforementioned derivative arc detector comprises a current sensor for developing a current signal corresponding to the currents at each end of the load and source ends of each phase in the field, and a current combiner connected to the aforementioned current sensor for receiving the aforementioned current signal and combining the current signal from the source end which has an opposing current signal from the load end. 9. The claim under clause 8 also includes additional current sensors at each junction point within the area. The aforementioned current combining device also combines the current signals from the additional current sensors with the current signals from the load and source end current sensors of the aforementioned area, respectively. 10. The arc fault detection system in the arc field consists of a derivative current arc detector for detecting arc fault conditions between line-to-line and to ground, and a derivative voltage detector for detecting series arc faults. 11. The system of claim number 10, whereby the aforementioned derivative voltage arc detector comprises a zero-sequence voltage arc detector. 12. The system of claim number 10 also includes a derivative phase current sensor for the detection of both series and parallel arc faults. 13. Arc fault measurement system in the arc zone, consisting of a derivative arc voltage detector for detecting derivative arc faults and a derivative phase current detector for detecting both series and parallel arc faults. 14. The system of claim 13, whereby the aforementioned derivative voltage arc detector comprises a zero-order derivative voltage arc detector. 15. Arc fault detection system in the arc zone, consisting of a derived current sensor for detecting line-to-line and ground arc conditions, and a derived phase current sensor for detecting both series and parallel arc faults. 16. Arc fault detection system in the arc fault zone of an electrical circuit, consisting of a voltage sensing device for detecting the voltage in the conductors of the aforementioned electrical circuit at both the source and load ends of the aforementioned zone, and a torque detector connected to the aforementioned sensing device to generate a differential signal corresponding to any difference between the voltage at the source and load ends of the aforementioned zone. 17. The system of claims under clause 16 also includes line impedance compensation devices for the elimination of the line impedance effects caused by voltage drops from the aforementioned differential signals. 18. The system of claims under Article 15 also includes an impedance stabilization network connected to both the source and load ends of the aforementioned area. 19. Arc Fault Detection System in the Arc Zone: This system is used to detect arc faults in a defined arc zone of an electrical circuit. It consists of a current transformer connected in a working manner to the conductors of the aforementioned circuit to generate a current signal corresponding to the current in the conductors; an arc detector connected to the current transformer to measure the current changes due to series arc faults in the conductors; and an impedance stabilization network connected to the source and load ends within the defined arc zone of the conductors. 20. Arc Fault Detection System in the Arc Zone: This system is used to detect arc faults within a defined arc zone of an electrical circuit. It consists of a voltage sensor connected to the source and load ends within a specific conductor zone of the circuit; a current sensor connected to the conductor adjacent to the source end of that zone; and an arc power sensor connected in conjunction with the voltage and current sensors to measure power loss through the conductor in that zone, corresponding to series arcing in the conductor within that zone. 21. Arc Fault Detection System in the Arc Zone: This system is used to detect arc faults in a defined arc zone of an electrical circuit. It comprises a voltage summator for summing the voltages of all phases of the circuit at both the source and load ends of the zone; a comparator for comparing the sum of the voltages at one end of the load and source and the sum of the voltages at the other end of each phase, and for generating a differential signal corresponding to any difference between them; a derivative current arc detector; and a ground fault detection system consisting of a current transformer detector connected in a functional manner to the conductor and neutral wire of the circuit for detecting the current difference between them and generating a corresponding ground fault signal. 22. A system for monitoring arc faults at electrical circuit connections, consisting of a device for monitoring the voltage difference at the aforementioned connection point and a device for generating a corresponding arc fault signal. 23. The system of claim 22, whereby the aforementioned device for direct monitoring consists of two toroidal coils, with the first coil connected at the aforementioned junction and the second coil for generating the arc fault signal, and whereby the second coil for generating the arc fault signal and whereby the secondary coil is connected in the monitoring network. 24. The system of claim 22, whereby the aforementioned meter consisting of a light-emitting diode (LED) connected to the aforementioned connection point shall be monitored, and a device responding to the light from the aforementioned LED for generating an arc fault signal, and a photoelectric switch responding to the light from the aforementioned LED for generating a corresponding arc fault signal. 25. The system of claim 24 where the aforementioned switch is connected in a network for monitoring multiple connection points and contains a device for identifying any of the aforementioned connection points where an arc fault occurs in response to a corresponding arc fault signal (Clause 25, drawing - figure).