MXPA00008027A - Electrical fault detection system - Google Patents

Abstract

An electrical fault detector system (10) detects (16) electrical faults in an electrical distribution system bymonitoring one or more conductors (14, 18) and producing an input signal representing one or more electrical signal conditions in the circuit to be monitored. This input signal is processed to develop a first signal representing the electrical current flow through the monitored circuit and a second signal representing signal components in a selected frequency range typical of arcing faults, and which exceed a predetermined threshold. The system also detects (20) ground faults in the circuit being monitored.

Description

SYSTEM OF ELECTRICAL FAILURE DETECTION FIELD OF THE INVENTION 5 The present invention relates to the protection of electrical circuits and, more particularly, to the detection of several electrical faults in an electrical circuit, for example, an analysis of the flow of current in the circuit, detection of faults of arc and detection of earth faults.

BACKGROUND OF THE INVENTION Electrical systems in residential, commercial and industrial applications usually include a board to receive electric power from a supply service. The energy is routed through protection devices to design branched circuits that supply one or more loads. These overcurrent devices are typically circuit breakers such as circuit breakers and fuses that are designed to interrupt the electrical current if the limits of the ^ tv conductors supplying the loads are exceeded. The interruption of the circuit reduces the risk of damage or the potential for property damage due to a resulting fire. Circuit breakers are the preferred type of circuit breaker because a mechanism of restoration allows its reuse. Typically, circuit breakers interrupt an electrical circuit to a Disconnection or trip condition such as a current overload or ground fault. The overload condition of ^^ current results when a current exceeds the normal conditions of continuous operation of the switch during a time interval determined by the current disconnect. A ground fault disconnect condition is created by the imbalance of currents flowing between a line conductor and a neutral conductor that could be caused by leakage current or arcing fault to ground.

JA Arc formation failures are commonly defined as ionized gas through the current between two ends of a broken conductor or in a contact with a fault or connector, between two conductors supplying a load, or between a conductor and ground. However, failures by arc formation may not cause a conventional circuit breaker to disconnect. Fault current levels by arcing can be reduced by load impedance to a level below the curve settings.

^ Disconnection of the circuit breaker. In addition, a failure of Arc formation that does not make contact with an earth conductor or with a person will not disconnect a ground fault protector. There are many conditions that can cause a failure by arcing For example, corroded connectors worn or old wires, contacts or insulation loose connections, cables damaged by nails or staples through the insulator, and electrical voltage caused by overload ^^ repeated, light rays, and so on. These faults can damage the conductor insulation and reach an unacceptable temperature. Arcing faults can cause fires if combustible materials are in close proximity. OBJECTS AND SUMMARY OF THE INVENTION It is an object of the present invention to provide a A system for detecting electrical faults and a method that reliably detects electrical faults, including overcurrent conditions and ground faults, as well as arc fault conditions ignored by conventional circuit breakers. Still another object of the invention is to provide an electrical fault detection system that uses a minimum number of highly reliable electronic components to perform most signal processing and analysis functions, which is relatively simple and very reliable in the operation. Other additional objects and advantages of the invention are apparent to those skilled in the art from the present specification taken with the accompanying drawings and the appended claims. In accordance with one aspect of the invention, • provides an electrical circuit fault detector comprising a bandpass filter circuit element ^^ that responds to an input signal representative of an electrical signal condition in a circuit that is going to monitoring to pass a frequency signal comprising signal components of said input signal falling within a first predetermined frequency band; a threshold detector circuit element coupled with said bandpass filter element and responding ? ^ a components of said frequency signal above a predetermined threshold amplitude to produce a corresponding frequency amplitude signal; and a first frequency signal conditioning circuit element coupled with the threshold detecting element and responsive to said frequency amplitude signal to produce a frequency amplitude output signal conditioned in a convenient manner to enter a controller. According to another aspect of the invention, ™ provides an electrical fault detector system that comprises a first sensor operatively coupled with a circuit to be monitored to produce an input signal representative of a signal condition in said circuit to be monitored; a ground fault sensor operatively coupled with said circuit to be monitored to produce an earth fault input signal representative of a ground fault current in said circuit to be monitored; an integrating circuit element ^^ coupled with said first sensor and responding to the input signal to develop a current signal 5 representative of current magnitude in said circuit to be monitored; a bandpass filter circuit element operatively coupled with said first sensor and responsive to the input signal to pass a frequency signal comprising signal components of said signal Jf entry in a predetermined frequency band; an earth fault amplifier circuit element coupled to said ground fault sensor to amplify the input signals to produce amplified ground fault signals; and a signal conditioning circuit element coupled with said bandpass filter circuit element, said integrating circuit element and said ground fault amplifying circuit for receiving and conditioning the current signal, the frequency signal and the ground fault signal w amplified for produce exit signs conditioned in a convenient way for a controller to enter. According to another aspect of the invention, there is provided a method for detecting arc faults in an electrical distribution system that includes a conductor of line connected to a load, said method comprises monitoring the line driver and produce a corresponding input signal; and filtering in bandpass said signal of ^^ input to two bands of predetermined frequency. In accordance with another aspect of the invention, an application-specific integrated circuit is provided which comprises a bandpass filter circuit element that responds to an input signal representative of a signal condition in a circuit that is going away. to monitor to pass a frequency signal that comprises components of < ^ fc signal of said input signal falling within a first predetermined frequency band; a threshold detector circuit element coupled to the bandpass filter circuit element and responsive to components of said frequency signal above a threshold amplitude predetermined to produce a corresponding frequency amplitude signal; a first frequency signal conditioning circuit element coupled with the threshold detecting circuit element and responding to the ^ signal of amplitude of frequency to produce a signal of The amplitude output of the conditioned frequency in a convenient manner for insertion into a controller According to another aspect of the invention, there is provided an electrical fault detecting circuit comprising a fault detecting circuit element of current to develop a current signal representative of the magnitude of current in the circuit to be monitored; a detector circuit element of arc-forming failure to develop an arc-forming fault signal in response to the detection of an arc-forming fault 5 in said circuit to be monitored; and an earth fault detector circuit element to produce a ground fault signal in response to the detection of a ground fault in the circuit to be monitored. In accordance with another aspect of the invention, an application-specific integrated circuit is provided for an electrical fault detector system comprising a current-sensing circuit element for developing a current signal representative of the current. magnitude of current in said circuit to be monitored; an arc-forming fault detector circuit element for developing an arc-forming fault signal in response to the detection of an arc-forming fault signal ^^ arch in said circuit to be monitored; and an element of ground fault detector circuit to produce a ground fault signal in response to ground fault detection in the circuit to be monitored. According to another aspect of the invention, there is provided an energy supply circuit comprising a voltage regulator circuit to produce a voltage of regulated direct current; and a zener diode in series with a ground circuit of said voltage regulator circuit for ^^ produce regulated positive and negative direct current output voltages. In accordance with another aspect of the invention, there is provided an energy supply circuit comprising a rectifier circuit; a capacitor in series between a line voltage source and the rectifier circuit to efficiently lower the line voltage; and a voltage regulator j ^ k voltage operatively coupled with the bridge circuit to produce a regulated direct current voltage. BRIEF DESCRIPTION OF THE DRAWINGS In the drawings: Figure 1 is a functional block diagram of an electrical failure detection system of the embodiment of the invention. Figure 2 is a schematic diagram of the electrical circuit for implementing the arc-fault detection system illustrated in Figure 1. Figures 3-6 are schematic diagrams of other details of the electrical circuit of Figure 2; and Figures 7A and 7B and 8A, 8B, 8C and 8D form a schematic diagram of an application-specific integrated circuit (CIEA) operating equivalently to the circuits 25 of Figures 3-6.

DESCRIPTION OF ILLUSTRATIVE MODALITIES Referring now to the drawings initially ^^ in Figure 1, a novel electrical fault detection system according to the invention is shown in block form. invention, and generally designated by the reference numeral 10. In the illustrative example, the fault detection system 10 is associated with an electrical circuit such as the 120 VAC circuit 12 to be monitored to determine faults. Of course, the invention is not limited to W use with a 120 VAC circuit. At least one sensor 16 is provided in association with 120 VAC circuit 12 to produce a signal representative of a signal condition, such as power, voltage or current in circuit 12 of 120 VAC. In the illustrated embodiment, this sensor 16 comprises a current change rate sensor (di / dt). A line conductor 14 of the 120 VAC circuit 12 passes through the current change rate sensor (di / dt) 16 which produces a current input signal representative of the ^ change in the flow of the current in line conductor 14.

In the illustrative embodiment, both the line conductor 14 and the neutral circuit 18 of the 120 VAC circuit 12 flows through a sensor or ground fault detector 20 which responds to the current flowing through the sides of the circuit. line and neutral of circuit 12 to produce a signal of output on an output 22. If the flow of the current through of the line and neutral conductors is different, this is an indicator of a ground fault. Preferably, each of the di / dt sensor 16 and the ground fault sensor 20 comprises a toroidal coil having an annular core surrounding the relevant conductors, with a toroidal sensor coil wound helically over the core. In the sensor 16, the core can be made of magnetic material such as ferpta, iron or molded permeable powder, so that the sensor is capable of ^^ respond to rapid changes in flow. An air gap can be cut in the core in certain cases to reduce permeability, and the core material is such that it does not become saturated during the relatively high current produced by some forms of arcing, so that detection of the arc is still possible. Particular requirements for the construction of the toroidal coil and the core for the ground fault sensor 20 may differ in some way from those for the di / dt 16 sensor, these fault sensors ^^ Earth or transformers are generally known in the technique. The di / dt sensor 16 provides an input to the arc-forming fault detector circuit 24 which is preferably a broadband noise detector circuit and a current fault detector circuit 26 which Preferably it is a current measuring circuit. He ground fault sensor 20 provides an input signal on line 22 to a ground fault detector circuit 28. ^^ Preferably, all components of the arc fault circuit detector 24, the fault detector circuit 5 of current 26 and the ground fault detecting circuit 28, as well as some other components of the circuit to be described later, are provided on a specific integrated circuit of the application 30. The convenient output signals from the specific integrated circuit from 2 ^ the application 30 are fed to a microcontroller 40 which, based on the analysis and further processing of the signals provided by the application-specific integrated circuit 30 makes a decision as to whether to send the disconnect signal to an output 42 to activate the disconnection circuit 44 which in The effect will change the conductor on the line 14 side of the 120 VAC circuit 12 to an open circuit condition as indicated diagrammatically in FIG. 1, or if it allows the line 14 side of the circuit 12 to remain connected to an ^ loading 50. 20 Referring also to Figure 2, some additional details of the circuit of the invention are illustrated. In the embodiment illustrated in Figure 2, the disconnect signal of the output of the microcontroller 42 is fed to the specific integrated circuit of the application 30 where is disjunctive with other signals (which will be described further forward) to disconnect the disconnect circuit 44, and feed it to the disconnect output 32. The illustrated disconnect circuit 44 includes a disconnect coil 46, such as a solenoid coil which, when sufficient current is flowing through from it, it will activate a solenoid plunger causing a mechanism to be released within a circuit breaker whereby the contacts 47 are opened and the line of load 50 is disconnected as illustrated in Figure 1. The disconnection circuit 44 as illustrated in the JA Figure 2 includes a tpac 48 in series with a disconnect coil 46 and the neutral line 18. This tpac 48 will be triggered by a photosensor tpac 50, when the tpac 50 is activated by emitting light energy from the emitting diode of light (DEL) 52. The light emitting diode 52 is coupled with the "disconnect" line of the application-specific integrated circuit and with a negative reference voltage VSS so that it is energized to emit light when a disconnection signal is given on line 32. ^ Briefly referring to a portion from power supply 60 in the circuit of Figure 2, in the illustrative embodiment a full-wave bridge rectifier circuit 62 is employed. Advantageously, a series capacitor 64 is coupled between the line conductor 14 and the circuit 62 rectifier bridge to lower efficiently the line voltage. In the modality illustratively, the capacitor has a value of substantially 0.56 microfarads so that it delivers approximately 15-25 volts of alternating current at rectifier bridge 62. This reduced line voltage is completely rectified and fixed at 14 volts by a 14 volt zener diode 65 In accordance with another feature of the invention, the cathode of a zener diode 66 is coupled to the ground pin or ground circuit 68 of a voltage regulator 70. The voltage regulator 70 produces a regulated voltage of -5 volts. direct current as VDD, while a • regulated voltage of -5 volts VSS is produced at the anode of zener diode 66, which is preferably a 5.6 volt zener diode. Also shown in Figure 2 is an entry of test switch 72 to microcontroller 40 for use in a "push to test" operation. That is, for purposes of testing the circuit, when a test switch (not shown) is engaged with that input of ^ test switch 72, the resistor Rl will cause a signal of simulated ground fault to be injected into the ground fault current transformer 20 for purposes of testing the proper operation of the system. Simultaneously, an AC voltage is coupled to a plug in the microcontroller, causing it to initiate a self-test mode.

The microcontroller 40 will then send a "clock" signal test "to the specific integrated circuit of the application 30 which will condition it and send a signal of failure frequency ^^ of simulated arc formation to the coil di / dt 16. If all circuits operate properly, the microcontroller must 5 receive signals of response that indicate both a ground fault and an arcing fault In accordance with a test program, only when both signals are received, the microcontroller will send an appropriate "disconnect" signal on line 42 to the input of "disconnect" enters the application-specific integrated circuit 30 which in turn will send a disconnect signal to the "disconnect" line 32 to the disconnect circuit 44 to activate the disconnect coil 46. Preferably, the coil Disconnection 46 is part of a circuit breaker 5 which can be reset manually by following the test procedure. schematically indicates the coil of the di / dt sensor 16 and the coil of the ground fault sensor 20 and the components of the related circuit 0 and their operating connections to the specific integrated circuit of the application 30. Also shown in Figure 2 are the operating connections of additional passive components, of the in-line and neutral sides of the 120 VAC circuit, and of convenient regulated direct current voltages 5 from the voltage regulator circuit 60 with respect to the specific integrated circuit of the application 30 and the microcontroller 40. ^ ± Referring again to Figure 1, additional components of the application-specific integrated circuit 5 of the application 30 will be described immediately below. The broadband noise detector 24 comprises first and second band pass filter circuits 80, 82 which receive the rate of change of the current signal of the di / dt sensor 16. According to the invention, ^ fc the band passages of these circuits 80 and 82 are selected to frequency bands that are representative of the typical frequency spectrum of arcing faults so that they substantially eliminate (statistically) signals at frequencies that may occur in the line that does not represent 15, this is that they are not due to, a failure by arc formation. In the illustrative embodiment, these bandpass frequencies are selected as typically 35 kilohertz and 70 kilohertz respectively. Each one of the band pass filter filters f and 82 feeds a filtered signal, which comprises those components of an input signal from the di / dt sensor that are within their respective bandpass frequency bands, to the respective threshold detector circuits 84 and 86. The threshold sensors 84 and 86 respond to those components of the frequency signals passed by bandpass filters 80 and 82 which are above a predetermined threshold amplitude to produce ^^ a frequency amplitude output corresponding to the signal conditioning circuits 88 and 90. These 5 circuits 88 and 90 produce a output signal conditioned in a convenient manner to enter the microcontroller 40. In the illustrated embodiment, these latter signal conditioning circuits 88 and 90 comprise one-shot circuits of ten microseconds to produce a pulse signal 2 ^ k unit. The output pulses generated by the one shots 88 and 90 are squared in respective wave squares 90, 92, and 94 (see Figure 4) before being combined in a Y 96 circuit whose output is fed to a "counter" input "of the microcontroller 40 as indicated in Figure 1. In the In the illustrative embodiment, a threshold of one volt is used for both threshold circuits 84 and 86. Additional details of the arc-forming fault detector circuit 24 are also shown in Figures 3 and 4. ^ Referring briefly to Figures 3 and 4, These schemes have been split into several parts labeled 3A, 3B and 4A, 4B to facilitate the illustration thereof. In addition to the circuits heretofore described, the arc-forming fault detector or wide-band noise detector circuit portion 24 also includes a circuit phase shift setting 81 that takes the level signals relatively low of the di / dt 16 sensor and adjusts them to eliminate phase shifts in the following stages. The ^^ offset adjustment feeds a ten (10) kilohertz high pass filter 83 which is fed into the respective amplifiers 5 and 85 which in turn are fed into the respective 35 kilohertz bandpass filters and 70 kilohertz 80 and 82 described above. The outputs of these bandpass filters are fed into absolute value circuits 89 and 91 which also include stages of ^^ amplifier that are fed into the threshold detectors 84 and 86 which are illustrated in Figure 4. It should be appreciated that these circuits as well as other circuits illustrated in Figures 3-6 that form part of the application-specific integrated circuit. They are shown in circuit form equivalent. The specific integrated circuit design of the application 30 is as illustrated in Figures 7 and 8. However, the operation functions of the application-specific integrated circuit are believed to be better understood • referring to the block diagram in Figure 1 and the equivalent circuits of Figures 3-6. Figures 7 and 8 have also been split into several parts labeled 7A, 7B and 8A, 8B, 8C and 8D. The small diagram in the upper left portion of Figure 8A shows how Figures 8A, 8B, 8C and 8D should be accommodated. 25 Referring again to Figure 1, and also to Figure 3, the current fault sensor or the current measurement portion 26 of the specific integrated circuit of ^^ the application 30 also receives the output signal from the di / dt sensor 16. An integrating circuit 100 develops a signal 5. representative of the magnitude of current in response to the output of the di / dt sensor 16. This signal is fed to another portion of the signal conditioning circuit 102 which includes an absolute value circuit as shown in Figure 1 and a circuit of gain 104 to produce a signal ^^ of conditioned current output in a convenient way to enter controller 40. Absolute value circuit 102 is similar in configuration and function to absolute value circuits 89 and 91 described above. Briefly, all these circuits take signals that go both negative and positive, and reverse any signal that goes to the negative in positive signals as they pass through the signals that go to the positive without changing. The output of the absolute value circuit 102 is feeds into the gain circuit 104 which includes a low current gain stage 106 and a high current gain stage 108. Briefly, the low current gain stage 106 applies a relatively greater amount of gain to the relatively low flows of way they increase the resolution of the current signal for relatively low current levels. On the other hand, the high current gain stage 108 applies a relatively lower gain to the relatively higher current levels in order to maintain a full range of current signal levels through the circuit. The outputs of the respective low current and high current gain stages are fed to the microcontroller 40. Referring again to Figure 1 and also < In Figure 6, the ground fault sensor 20 feeds a ground fault amplifier 120 and an absolute value circuit 122 which forms the ground fault detecting circuit 28. The ground fault amplifier 120 essentially amplifies the difference low level in flow of current between line 14 and neutral 18 as detected by ground fault sensor 20. The absolute value circuit is similar in operation and function to value circuits ^^ Absolute described above with reference to the Figures 3 and 4, because it essentially converts the signals that go to negative in signals to the positive and passes the signals that go to the positive without changing. Referring now to Figure 4B, the line voltage is also conditioned to a circuit 130 and fed to the microcontroller for further analysis and processing.

This circuit 130 includes a line voltage divider 132 the which divides the line voltage at a convenient lower level for additional processing, a difference amplifier 134 ^^ which takes the output of the line voltage divider and changes it to the ground level of the circuit to be rectified, and an absolute value circuit 136. The voltage of the difference amplifier 134 is fed through the absolute value circuit 136 which has the same configuration and function as described above for the absolute value circuits described above. The U output of absolute value circuit 136 is fed to microcontroller 40. Referring again to Figure 1 and also to Figure 5, a fault finding circuit 140 takes a pulse input (pulse_in) from the microcontroller 40 to check and see if the microcontroller is still active. If no pulses are present in this output of the microcontroller then a disconnection (signal disconnection) signal is sent to the disconnection circuit by means of the • fault finding circuit 140 (via line 32 of the Figure 2). A related circuit, a voltage monitor (VDD) 142 sends a reset signal (logic 0) to a microcontroller input 40 when the voltage VDD falls below 4.0 volts of direct current so as to avoid microcontroller errors. 25 With reference to Figure 3A, a "push to test" amplifier circuit 150. This portion of the circuit is also shown and designated by the ^^ reference number 150 in Figure 1. This circuit 150 receives the test clock signal from the microcontroller when the "push to test" switch at input 72 is activated and conditions it for input to a coil Test on the di / dt 16 sensor for push function purposes to test as described above. B | As indicated above, Figures 1-8 illustrate one embodiment of an application-specific integrated circuit for performing the aforementioned operations. The provision of the detector circuit as a specific integrated circuit of the application is advantageous, because allows circuits to be easily incorporated in a variety of environments. This is mainly due to the small size and relatively modest power requirements of the application-specific integrated circuit. That is, this detector circuit can be incorporated not only in boards or other distributors, but can also be located in individual loads. This is true for both industrial, commercial and residential applications. For example, the specific integrated circuit of the detector application could be incorporated in equipment or machinery with energy industrial and / or commercial electrical, as well as the product of consumption such as computers, audiovisual equipment, household appliances and the like. ^^ What has been illustrated and described here is a novel and improved electrical fault detector system which includes a novel detector circuit and an integrated circuit specific to the novel application incorporating the detector circuit. A novel and improved power supply circuit is also described above. Although modalities have been illustrated and described? Particular applications of the present invention, it will be understood that this is not limited to the construction and precise compositions described herein and that various modifications, changes, and variations may be apparent from the foregoing descriptions without departing from the spirit and scope of the invention. as defined in the appended claims.

Claims (60)

1. NOVELTY OF THE INVENTION Having described the foregoing invention, it is considered as a novelty and therefore the content of the following is claimed as property. 5 CLAIMS 1. A power supply circuit comprising: a rectifier circuit; a series capacitor between a line voltage source and the rectifier circuit to efficiently drop the voltage of the line; and a A voltage regulator operatively coupled with the rectifier circuit to produce a regulated direct current voltage; and also includes a zener diode in series with a ground circuit of the voltage regulator to produce positive regulated direct current output voltages and 15 negative.
2. 2. A power supply circuit comprising: a voltage regulating circuit for producing a regulated direct current voltage; and a zener diode in series ft with a ground circuit of said regulator circuit of 20 voltage to produce positive and negative regulated direct current output voltages.
3. 3. An electrical fault detector comprising: one or more bandpass filter circuits that respond to an input signal representative of a signal condition 25 electric in a circuit that is going to be monitored to pass a or more frequency signals comprising signal components of said input signal falling within one or more bands ^^ of predetermined frequency, the one or more bands are selected to detect broadband noise in a typical frequency spectrum of arc formation; a current signal input circuit that responds to the input signal to develop an analog current signal representative of a current magnitude in the circuit to be monitored; and signal conditioning circuit M respective coupled with the bandpass filter circuits and with the current signal input circuit for receiving and conditioning said one or more frequency signals and the current signal to produce respective conditioned output signals in a convenient manner for the 15 entry to a controller.
4. 4. The electrical failure detector of claim 3 and characterized in that the signal conditioning circuits include a detector circuit of § threshold coupled with each of the one or more filter circuits 20 of bandpass and which responds to components of the one or more frequency signals having an amplitude above a predetermined threshold amplitude to produce a corresponding threshold output signal, a one-shot circuit coupled with each detector circuit. threshold and that responds to 25 the threshold output signal to produce a pulse signal to enter a controller.
5. 5. The electrical fault detector according to claim 4, characterized in that it also includes a conjunction circuit Y coupled with each one of the circuits of a shot to receive and join said unitary pulse signals to enter a controller.
6. 6. The electric fault detector according to claim 3, characterized in that it also includes a ground fault amplifier circuit for ?? amplify signals from a ground fault sensor to produce amplified ground fault signals; and a ground fault signal conditioning circuit coupled with the ground fault amplifier and responding to amplified ground fault signals to produce 15 ground fault signals conveniently conditioned to enter a controller.
7. 7. The electric failure detector according to claim 3, characterized in that ™ the signal conditioning circuits comprise a low gain circuit for adjusting a gain of said current signal by the first predetermined amount and a high gain circuit for adjusting a gain of said current signal by a second predetermined amount greater than the first predetermined amount, 25 to increase the resolution of said current signal to relatively low current levels while maintaining a full range of current signal levels ^^ for relatively high current levels.
8. 8. The electrical fault detector according to claim 3, characterized in that it also includes a phase shift adjustment circuit coupled between the current signal input circuit and the signal conditioning circuit to amplify and change the level of said current signal to eliminate ^ 0 phase shifts.
9. 9. The electric fault detector according to claim 8, characterized in that it also includes an absolute value circuit coupled between the current phase shift adjustment circuit and the circuit 15 signal conditioning current to reverse any negative current signal in a positive current signal and to pass through the positive signals without change. ™ 10.
10. The electrical fault detector in compliance 20 with what is claimed in claim 3, characterized in that it also includes a sensor transformer of current change rate to produce the input signal, and wherein the current signal input circuit comprises a mitering circuit. 25 11.
11. The electrical fault detector in accordance with what is claimed in claim 6, characterized in that it also includes a ground fault current transformer ^^ comprising said ground fault sensor.
12. The electrical fault detector in accordance with claim 5, characterized in that it also includes a controller coupled with said circuit Y to receive signals coupled with and with one of these signal conditioning circuits to receive conditioned current signals.
13. 13. The electric failure detector according to claim 6, characterized in that it also includes a controller coupled with all the signal conditioning circuits to receive all the conditioned output signals.
14. 14. The electric failure detector according to claim 7, characterized in that it also includes a test circuit to produce a test input signal in place of the input signal, to test »The electric fault detector.
15. 15. An electrical fault detector system comprising: a first sensor operatively coupled with a circuit to be monitored to produce an input signal representative of a signal condition in the circuit to be monitored; a bandpass filter circuit 25 operatively coupled with the first sensor and responsive to the input signal for passing a sequence signal comprising signal components of said input signal in a , J or more bands of predetermined frequency, said one or more frequency bands being selected to detect wideband noise in a typical frequency spectrum of arcing faults; a current signal input circuit coupled to the first sensor and which responds to the input signal to develop an analog current signal representative of current magnitude in the circuit f ^ h to be monitored; and a signal conditioning circuit coupled with the bandpass filter circuit and the current signal input circuit for receiving and conditioning said frequency signal and the current signal to produce conditioned output signals in a form 15 convenient for entry to a controller.
16. 16. The system according to claim 15, characterized in that it also includes a controller operatively coupled with said signal conditioning circuit to receive the output signals 20 and adapted to produce a disconnect signal.
17. 17. The system according to claim 15, characterized in that the signal conditioning circuit includes a threshold detector circuit coupled with the bandpass filter circuit for 25 pass substantially only the components of the signals of frequency over a preselected threshold amplitude.
18. 18. The system according to claim 14, characterized in that the signal conditioning circuits comprise a low gain circuit 5 for adjusting a gain of the current signal by a first predetermined amount and a gain circuit. high to adjust a gain of the current signal by a second predetermined amount greater than the first predetermined amount, to increase the M resolution of the current signal for relatively low current levels while maintaining a full range of current levels. current signals for relatively high current levels.
19. 19. The system according to claim 15, characterized in that it also includes a power supply circuit, including the power supply circuit: a rectifier circuit; a series capacitor coupled between the line voltage source and the »Rectifier circuit for efficiently dropping the line voltage 20; and a voltage regulator circuit operatively coupled with the rectifier circuit to produce a regulated direct current voltage.
20. 20. The system according to claim claimed in claim 19, characterized in that the circuit of 25 power supply also includes a zener diode in series with a ground circuit of said voltage regulator circuit to produce regulated direct current output voltages ^^ positive and negative.
21. 21. The system according to claim 5, characterized in that it also includes a disconnection circuit that responds to a disconnection signal to channel an open circuit condition in the circuit to be monitored.
22. 22. The system in accordance with that claimed in claim 15, characterized in that it also includes: a ground fault sensor operatively coupled with the circuit to be monitored to produce an earth fault input signal representative of any fault current of ground in said circuit that is going to 15 monitor; the signal conditioning circuit is further coupled with the ground fault sensor to receive and condition the ground fault signal to produce a conditioned output signal in a convenient manner for »Enter it into a controller.
23. 23. The system according to claim 22, characterized in that it further includes a controller operatively coupled with the signal conditioning circuit to receive the output signals and adapted to produce a disconnect signal. 25
24. 24. A specific integrated circuit for application comprising: one or more bandpass filter circuits that respond to the input signal representative of a signal condition in a circuit to be monitored to pass one or more frequency signals comprising signal components of said input signal falling within one or more predetermined frequency bands; a current signal input circuit that responds to the input signal to develop an analog current signal representative of the magnitude of current in the circuit to be monitored; and signal conditioning circuits • respective coupled with the bandpass filter circuits and with the current signal input circuit to receive and condition the one or more frequency signals and the current signal to produce output signals 15 conditioned in a convenient way to enter a controller.
25. 25. The application-specific integrated circuit in accordance with claim 24, > characterized because the conditioning circuits of The signals comprise a threshold detector circuit coupled with each of the one or more bandpass filter circuits and responsive to the components of the one or more frequency signals having an amplitude above a predetermined threshold amplitude for produce an output signal of 25 corresponding threshold, and a one-shot circuit coupled with - * »----" - Each threshold detector circuit responds to the threshold output signal to produce a unit pulse signal for ^^ entering a controller.
26. 26. The application-specific integrated circuit 5 according to claim 24, characterized in that it also includes a Y circuit coupled with each of the circuits of a shot to receive and join the signals of unit impulse to enter a controller .
27. 27. The application-specific integrated circuit according to claim 24, further comprising a ground fault amplifying circuit for amplifying signals from a ground fault sensor to produce amplified ground fault signals; and a signal conditioning circuit of 15 ground fault coupled with the ground fault amplifier and responding to amplified ground fault signals to produce ground fault signals conditioned in a convenient manner to enter a controller. ^
28. 28. An electrical fault detector circuit that 20 comprises: a current sensing circuit for developing an analog current signal representative of the magnitude of current of a circuit to be monitored; an arc-forming failure detector circuit for developing an arcing-fault signal in response to the 25 detection of an arcing fault in said circuit which is going to be monitored; and a ground fault detector circuit to produce a ground fault signal as .A response to the detection of a ground fault in the circuit to be monitored.
29. 29. The electrical fault detector circuit according to claim 28, characterized in that the arcing fault detection circuit comprises: one or more bandpass filter circuits that respond to the input signal? & representative of a signal condition of a circuit to be monitored to pass one or more frequency signals comprising signal components of the input signal falling within one or more bands of predetermined frequency, said one or more bands of frequency are selected to detect 15 broadband noise in a frequency spectrum typical of arc-forming faults; a current signal input circuit that responds to the input signal to develop an analog current signal representative of the ^ magnitude of current in the circuit to be monitored; 20 and respective signal conditioning circuits coupled with the bandpass filter circuits and with the current signal input circuit for receiving and conditioning the frequency signal and the current signal to produce respective conditioned output signals in 25 a convenient way to enter a controller.
30. 30. The electric failure detector circuit according to claim 29, characterized in that the signal conditioning circuits comprise a threshold detector circuit coupled with each of the one or more bandpass filter circuits and that respond to components of said one or more frequency signals having an amplitude above a predetermined threshold amplitude to produce a corresponding threshold output signal, and a one-shot circuit faithfully coupled to each threshold detector circuit and responsive to same said threshold output signal to produce a unit impulse signal to enter a controller.
31. 31. The electrical fault detector circuit according to claim 30, 15 characterized in that it also includes a Y circuit coupled with each of the circuits of a shot to receive and combine the unitary pulse signals to enter a controller.
32. 32. An electrical fault detector circuit of »Compliance with the claim in claim 28, Characterized in that the ground fault detecting circuit includes a ground fault amplifier for amplifying signals from a ground fault sensor to produce amplified earth fault signals; and a ground fault signal conditioning circuit coupled with the 25 ground fault amplifier and that responds to signals from ground fault amplified to produce signals of ground fault conditioning in a convenient way to enter ^^ a controller.
33. 33. The electrical fault detector according to claim 28, characterized in that the signal conditioning circuits comprise a low gain circuit for adjusting a gain of said current signal by the first predetermined amount and a gain circuit. high to adjust a gain of ?? said current signal by a second predetermined amount greater than the first predetermined amount, to increase the resolution of said current signal for relatively low current levels while maintaining a full range of current signal levels 15 for relatively high current levels.
34. 34. The electrical failure detector according to claim 28, characterized in that it also includes a phase shift adjustment circuit coupled between the current signal input circuit and the 20 signal conditioning circuit to amplify and change the level of said current signal to eliminate phase shifts; and an absolute value circuit coupled between the current phase shift adjustment circuit and the signal conditioning circuits for inverting 25 any negative current signal in a current signal positive and to pass positive current signals without changing them. ^^
35. 35. An application-specific integrated circuit for an electrical fault detector system comprising: a current sensing circuit for developing an analog current signal representative of the magnitude of current of a circuit to be monitored; an arc-forming fault detector circuit for developing an arcing-fault signal in response to the < fl | detection of an arcing fault in said circuit to be monitored; and a ground fault detector circuit to produce a ground fault signal in response to the detection of a ground fault in the circuit to be monitored. 15
36. 36. The specific integrated circuit of the application in accordance with what is claimed in the claim 35, comprising: one or more bandpass filter circuits that respond to the input signal representative of a ™ Signal condition of a circuit to be monitored for 20 passing one or more frequency signals comprising signal components of the input signal falling within one or more bands of predetermined frequency, said one or more frequency bands being selected to detect broadband noise in a frequency spectrum typical of faults by 25 bow formation; a signal input circuit current that responds to the input signal to develop an analog current signal representative of the magnitude of A current in the circuit to be monitored; and respective signal conditioning circuits coupled with the bandpass filter circuits and with the current signal input circuit for receiving and conditioning the frequency signal and the analog current signal to produce respective conditioned output signals in a convenient way to enter a controller. B
37. 37. The specific integrated circuit of the application according to claim 36, and characterized in that the signal conditioning circuits comprise a threshold detector circuit coupled with each of the one or more pass filter circuits from 15 and responding to components of said frequency signals having an amplitude above a predetermined threshold amplitude to produce a corresponding threshold output signal, and a one-shot circuit coupled with each threshold detector circuit and responding at the same said 20 threshold output signal to produce a unit impulse signal to enter a controller.
38. 38. The application specific integrated circuit according to claim 35, characterized in that the fault detection circuit includes a 25 ground fault amplifier to amplify signals from a ground fault sensor to produce amplified ground fault signals, and a ground fault signal conditioning circuit coupled to the ground fault amplifier and which responds to amplified ground fault signals to produce ground fault signals Earth conditioned in a convenient way to enter a controller.
39. The specific integrated circuit of the application according to claim 35, characterized in that the signal conditioning circuits comprise a low gain circuit for adjusting a gain of said current signal by the first predetermined amount and a gain circuit. high to adjust a gain of said current signal by a second predetermined amount greater than the first predetermined amount, to increase the resolution of said current signal for relatively low current levels while maintaining a full range of current signal levels for relatively high current levels.
40. 40. The specific integrated circuit of the application in accordance with the claim in the claim 35 and which further includes a phase shift adjustment circuit coupled between the current signal input circuit and the current signal conditioning circuit for amplify and change the level of said current signal to eliminate phase shifts; and an absolute value circuit ^^ coupled between the current phase shift adjustment circuit and the signal conditioning circuits to reverse any negative current signal in a positive current signal and to pass positive current signals without changing them .
41. 41. The specific integrated circuit of the application in accordance with what is claimed in the claim M 35 characterized in that it also includes a test circuit to produce a test input signal for test purposes.
42. 42. The specific integrated circuit of the application in accordance with what is claimed in the claim 15 24 characterized in that it also includes a test circuit to produce a test input signal for testing purposes.
43. 43. The electrical fault detector in accordance »With what is claimed in claim 3, characterized in that 20 further includes a controller that receives the conditioned output signals and, based on the analysis and processing of these signals, makes a decision as to whether or not to produce a disconnection signal.
44. 44. The electric fault detector in accordance with claim 15, characterized in that it also includes a controller that receives the conditioned output signals and, based on the analysis and processing of ^ these signals, it makes a decision whether or not to produce a disconnection signal.
45. 45. The circuit according to claim 29, characterized in that it also includes a controller that receives the analog current signal, the arcing fault signal and the ground fault signal and, based on the analysis and processing said signals, f ^ k makes a decision as to whether or not to produce a disconnection signal.
46. 46. An integrated circuit for use in the controlled processor device connected with at least one power line so that the combination of the integrated circuit and the processor-controlled device 15 can detect faults in the power line, this integrated circuit comprises: a first input to receive an alternative signal from an arcing fault sensor coupled with the power line; at least one bandpass filter connected to the first input to pass 20 only the components of the alternative signal within a prescribed frequency band, a threshold detector that receives the components of the alternating signal passed through the filter to compare the components of the signal with a predetermined threshold and produce an output signal when exceeds 25 the predetermined threshold; a pulse generator that receives the fc. output signal from the threshold detector that produces a corresponding output pulse; a first exit that receives ^ K the output pulses of the pulse generator to couple those pulses with the processor; a mtegrator connected to the first input to integrate the alternative signal and produce a signal representing the resulting integral; an absolute value circuit that receives the integral signal from the integrator and produces an output signal that represents the absolute value of that integral; a second exit that receives M the integral signal of absolute value to couple that signal with the processor; a second input to receive a signal from the ground fault sensor coupled with said power line; an amplifier connected to the second input to amplify the ground fault signal from the sensor 15 earth fault; an absolute value circuit that receives the amplified ground fault signal and produces an output signal that represents the absolute value of the amplified ground fault signal; and a third output that receives the signal »Of absolute value ground fault to couple that signal with 20 the processor.
47. 47. The integrated circuit according to claim 46, characterized in that it also includes a second bandpass filter connected to the first input to pass only the components of the 25 alternative signal within a second frequency band prescribed a second threshold detector that receives the components of said alternative signal passed by the second ^ ± filter to compare the components of the signal with a second predetermined threshold and producing an output signal when 5 the second predetermined threshold is exceeded; a second pulse generator that receives the output signal from the second threshold detector and produces a corresponding output pulse; a logic element that receives the output pulses from both pulse generators and what happens ? 6 these pulses only when the output pulses of both pulse generators are present substantially at the same time, and the first output receiving the output pulses of the logic element for coupling those pulses with the processor.
48. 48. The integrated circuit according to claim 15, characterized in that it also includes a fourth input to receive a test signal, an amplifier to adjust the amplitude of that test signal, and a fourth output that receives the output of the amplifier for ™ Couple the test signal with the training failure sensor 20 of arch.
49. 49. The integrated circuit as claimed in claim 46, characterized in that it also includes at least one power line input to receive the power line signal, an element of 25 signal conditioning to adjust at least the amplitude of the power line signal, and a power line output that receives the adjusted power line signal .A to couple the signal with the processor.
50. 50. The integrated circuit according to claim 5, characterized in that it includes a fault-finding circuit to receive a signal output from the discoverer of faults from the processor, determining from this signal of the fault discoverer. if the processor is active, and produce a disconnect signal if < A it is determined that the processor is not active.
51. 51. An integrated circuit for use in the controlled processor device connected with at least one power line so that the combination of the integrated circuit and the processor-controlled device 15 can detect faults in the power line, this integrated circuit comprises: a first input to receive an alternative signal from an arcing fault sensor coupled with the power line; a first pass filter ^ band connected to the first entry to pass only the 20 components of the alternative signal within a prescribed first frequency; a first threshold detector that receives the components of the alternating signal passed through the filter to compare the components of the signal with a first predetermined threshold and produce an output signal when it exceeds 25 the predetermined threshold; a first pulse generator that receives the output signal from the first threshold detector that produces a corresponding output pulse; a ^^ second bandpass filter connected to the first input to pass only the components of the alternative signal within a second frequency band prescribed; a second threshold detector that receives the components of said alternative signal passed through the second filter to compare the components of the signal with a second predetermined threshold and producing an output signal when AA the second predetermined threshold is exceeded; a second pulse generator that receives the output signal from the second threshold detector and produces a corresponding output pulse; a logic element that receives the output pulses from both pulse generators and what happens These pulses only occur when the output pulses of both pulse generators are present substantially at the same time, a first output that receives the output pulses from the pulse generator to couple those pulses with the pulse. »Processor; an integrator connected to the first entry 20 to integrate the alternative signal and produce a signal representing the resulting integral; an absolute value circuit that receives the integral signal from the integrator and produces an output signal that represents the absolute value of that integral; a second exit that receives 25 the absolute value integral signal to couple that signal with the processor; a second input to receive a signal from the ground fault sensor coupled with said power line; ^ & an amplifier connected to the second input to amplify the ground fault signal from the ground fault sensor; an absolute value circuit that receives the amplified ground fault signal and produces an output signal that represents the absolute value of the amplified ground fault signal; and a third output that receives the absolute value ground fault signal to couple that signal with B | the processor, a fourth input to receive a test signal, an amplifier to adjust the amplitude of the test signal, and a fourth output that receives the output of the amplifier to couple the test signal with the arcing fault sensor , at least one line entry 15 power to receive the power line signal, signal conditioning elements to adjust at least the amplitude of the power line signal, and a power line output that receives the adjusted power line signal ft to couple that signal to the processor, and a discoverer circuit 20 failures to receive a processor-discoverer signal output, determining from the fault discoverer signal if the processor is active, and producing a disconnect signal if it is determined that the processor is not active.
52. 52. The electrical fault detector in accordance 25 with what is claimed in claim 4, characterized in that it also includes a controller that receives the conditioned output signals and, based on the analysis and processing of ^^ these signals, makes a decision as to whether or not it produces a disconnection signal.
53. 53. The electric fault detector according to claim 16, characterized in that it also includes a controller that receives the conditioned output signals and, based on the analysis and processing of these signals, makes a decision as to whether or not it produces a signal ? of disconnection.
54. 54. The circuit according to claim 25, characterized in that it also includes a controller that receives the analog current signal, the arcing fault signal and the ground fault signal and, Based on the analysis and processing of said signals, it makes a decision as to whether or not it produces a disconnection signal.
55. 55. An integrated circuit for use in the connected processor-connected device with at least »An electric power line so that the combination of 20 integrated circuit and the controlled processor device can detect faults in the power line, this integrated circuit comprises: a first input to receive an alternative signal from an arcing fault sensor coupled with the power line; at least one filter 25 bandpass connected to the first entry to pass only the components of the alternative signal within a prescribed frequency band; a threshold detector that < ^ b receives the components of the alternating signal passed through the filter to compare the components of the signal with a first predetermined threshold and produce an output signal when the predetermined threshold is exceeded; a pulse generator that receives the output signal from the threshold detector and produces a corresponding output pulse; a first output that receives the output pulses of the pulse generator ^ k to couple those pulses with the processor; an integrator connected to the first input to integrate the alternative signal and produce a signal representing the resulting integral; an absolute value circuit that receives the integral signal from the integrator and produces a signal of 15 output that represents the absolute value of that integral; a second output that receives the integral signal of absolute value to couple that signal with the processor; a second input to receive a signal from the ground fault sensor coupled with said power line; an amplifier connected to the 20 second input to amplify the ground fault signal from the ground fault sensor; an absolute value circuit that receives the amplified ground fault signal and produces an output signal that represents the absolute value of the amplified ground fault signal; and a third 25 output that receives the absolute value ground fault signal to couple that signal with the processor.
56. 56. The integrated circuit in accordance with A claimed in claim 55, characterized in that it also includes a second bandpass filter connected to the first input to pass only the components of the alternative signal within a second frequency band prescribed; a second threshold detector that receives the components of said alternative signal passed through the second filter to compare the components of the signal with a second ? j predetermined threshold and producing an output signal when the second predetermined threshold is exceeded; a second pulse generator that receives the output signal from the second threshold detector and produces a corresponding output pulse; a logical element that receives the impulses of 15 output from both pulse generators and which passes these pulses only when the output pulses of both pulse generators are present substantially at the same time, and the first output that receives the output pulses of the I logical element to couple these pulses with the processor.
57. 57. The integrated circuit according to claim 55, further comprising a fourth input for receiving a test signal, an amplifier for adjusting the amplitude of that test signal, and a fourth output receiving the output. of the amplifier for 25 coupling the test signal with the formation failure sensor of Arc .
58. 58. The integrated circuit in accordance with ^ fc claimed in claim 55, characterized in that it includes a first power line input for receiving the power line signal 5, a signal conditioning element for adjusting at least the amplitude of the power line signal, and a power line output that receives the adjusted power line signal to couple the signal with the processor. > ^ h
59. 59. The integrated circuit according to claim 55, characterized in that it includes a fault-finding circuit to receive a processor-discoverable signal output from the processor, determining from the fault-finding signal whether the processor is active, 15 and produce a disconnect signal if it is determined that the processor is not active.
60. 60. An integrated circuit for use in the controlled processor device connected with at least one electric power line so that the combination of the 20 integrated circuit and the controlled processor device can detect faults in the power line, this integrated circuit comprises: a first input to receive an alternative signal from an arcing fault sensor coupled with the power line; a first pass filter 25 band connected to the first entry to pass only the components of the alternative signal within a prescribed first frequency; a first threshold detector which receives the components of the alternating signal passed through the filter to compare the components of the signal with a first predetermined threshold 5 and produce an output signal when the predetermined threshold is exceeded; a first pulse generator that receives the output signal from the first threshold detector that produces a corresponding output pulse; a second bandpass filter connected to the first, ^ k input to pass only the components of the alternative signal within a second frequency band prescribed; a second threshold detector that receives the components of said alternative signal passed through the second filter to compare the components of the signal with a second 15 predetermined threshold and producing an output signal when the second predetermined threshold is exceeded; a second pulse generator that receives the output signal from the second threshold detector and produces a corresponding output pulse; a logical element that receives the impulses of The output from both pulse generators and which passes these pulses only when the output pulses of both pulse generators are present substantially at the same time, a first output that receives the output pulses of the pulse generator to couple those pulses with he 25 processor; an integrator connected to the first entry to integrate the alternative signal and produce a signal representing the resulting integral; an absolute value A circuit that receives the integral signal from the integrator and produces an output signal representing the absolute value of that integral; a second output that receives the integral signal of absolute value to couple that signal with the processor; a second input to receive a signal from the ground fault sensor coupled with said power line; an amplifier connected to the second input to fl) amplify the ground fault signal from the ground fault sensor; an absolute value circuit that receives the amplified ground fault signal and produces an output signal that represents the absolute value of the amplified ground fault signal; and a third output that receives the signal 15 absolute value earth fault to couple that signal with the processor, a fourth input to receive a test signal, an amplifier to adjust the amplitude of the signal ^ test, and a fourth output that receives the output of the W amplifier to couple the test signal with the sensor 20 Arc formation fault, at least one power line input to receive the power line signal, signal conditioning elements to adjust at least the amplitude of the power line signal, and a power line output which receives the adjusted power line signal 25 to attach that signal to the processor, and a discoverer circuit of faults to receive a signal output from the processor's fault discoverer, determining from the jtifc discoverer signal of faults if the processor is active, and producing a disconnect signal if it is determined that the processor is not active.