CN1976152A - Arc fault detector - Google Patents

Abstract

An arc fault detector, as a stand alone device or in combination with a circuit interrupting device such as a ground fault interrupter (GFCI), protects from potentially dangerous arc fault conditions. The device utilizes a line side or load side series connected inductance having an air or magnetic core to generate the derivative di/dt signal of the arc current in the conductor. The derivative signal is fed to an arc fault detector where it is analyzed for the presence of arcing. The device on each of the multi-conductors of the power distribution network can have series connected inductors for detecting phase arc/neutrality arc or multiphase arc.

Description

Arc fault detector

The application be on December 22nd, 2003 application, sequence number is that the priority of its patent application day is enjoyed in the part continuation application and the requirement of 10/743,248 patent application.

Technical field

The present invention relates to a kind of equipment that is used for arc fault detection, relate in particular to the arc fault detector of a kind of independently arc fault detector and combined circuit contact maker device.

Background technology

Circuit-breaker, fuse and ground fault circuit interrupter (GFCI) are to protect the person and property to avoid the usual means of the electric fault of danger for being used to.Property loss and the disaster that is caused by the detected electric fault of these protective devices still do not taking place.A kind of such electric fault that typically is not detected is an arc fault.Electric arc is hiding danger because of the high temperature that wherein contains.Thereby main in the starting stage on fire, they very likely damage.Yet electric arc only just triggers GFCI when having produced enough electric current leakages over the ground.In addition, electric arc only just triggers circuit breaker when the electric current that flows through electric arc surpasses the trigger parameter of heat/magnetic mechanism of circuit breaker.Therefore, in order to detect and to interrupt electric arc, need the protective device of another kind of type.The arc detector that its output is used for circuits for triggering interrupt mechanism is called as arc fault circuit interrupter (AFCI).

The reason that electric arc produces is a lot, for example: the insulator and the distribution that wear out or wear and tear; Machinery or voltage power that excessively use of cause, super-high-current or lightning strike cause; Loosening connection; And the mechanical failure of insulator and distribution.In dwelling house and commercial building two kinds of electric arcs can take place: contact electric arc and line electric arc.Contact or crosstalk arc appear between two contacts of connecting with load.Therefore, the electric current that flows through in the load control electric arc.Line electric arc or electric arc in parallel appear between two conductors of circuit or between conductor and the ground.Under such situation, electric arc and the load that any one is current are parallel, and source impedance provides the unique restriction to the electric current that flows through in the electric arc.

Fig. 1 has described an example of contact electric arc.The conductor 114,116 that comprises cable 110 is wrapped in by insulator 112 and by separated from one another.The part of conductor 114 disconnects, and produces a series of gaps 118 in conductor 114.Under certain conditions, electric arc will be crossed over these gaps and take place, and produces a large amount of localized heats.The heat that produces because of electric arc may be enough to damage also charing near the insulator of electric arc 119.If allow electric arc to continue, then the heat of Chan Shenging is enough to cause burning.

Fig. 2 shows the schematic diagram of the example of having described a line electric arc.Cable 120 comprises the electric conductor 124,126 that is covered and pass through internal insulator 128 separation by outer insulator 122.In the degeneration of the internal insulator at 121 places or damage and to cause between two conductors 134 and 126 and line fault electric arc 123 occurs.Internal insulator may be lightning before therefore to the impact of distributing system and by charing, perhaps because such as the metal chair legs incision such mechanism of extension cord and cut off.

The potential destructive result that electric arc causes is widely known by the people, and has also developed the method for a lot of detection electric arcs in the prior art.Most prior art all relates to detection and is created in high-frequency signal on the alternating current circuit because of electric arc.

There is a large amount of prior aries in the arc-detection field.The some of them prior art relates to the example of special electric arc.The patent No. of for example authorizing people such as Renn is the device that 4,376,243 United States Patent (USP) has been taught a kind of work under direct current (DC) electric current.The patent No. of authorizing Rivera is that 4,658,322 United States Patent (USP) has been taught the device that detects electric arc in the electronic device unit of sealing.The patent No. of authorizing Nebon is that 4,878,144 United States Patent (USP) has been taught the device that is used for detecting the light that produces because of the electric arc between the circuit-breaker contact.

In addition, have much to relate to and detect the patent that exchanges the electric arc on (AC) power transmission line, they disclose the method for multiple detection hf electric arc signal.For example, the patent No. of authorizing people such as Beihoff is 5,185,684 and 5,206, and 596 United States Patent (USP) has used a kind of detection means of complexity, and it detects electric field and the magnetic field that produces around the distribution respectively.The patent No. of authorizing Dollar is that 5,590,012 United States Patent (USP) has been taught the high-frequency current in the closed path of measuring around the inductor of placing in the line, and this inductor can be the magnetic trigger mechanism of circuit breaker.In another testing circuit that is proposed by Dollar, high-frequency voltage signal is extracted out with the parallel high pass filter of placing of load from circuit by one.

Can from prior art, find several different methods to be used for verifying arc discharge and it is distinguished from other noise sources.Most prior aries have all related to complicated signal processing and analysis.The patent No. of authorizing Ragsdale is that 5,280,404 United States Patent (USP) has been taught by being pulse with the arc discharge conversion of signals and counting this pulse and search for the series connection arc discharge.

In addition, some patents detect arc discharge by the first derivative or the second dervative of getting detected signal, for example, the patent No. of authorizing people such as Mackenzie is that 5,224,006 the United States Patent (USP) and the patent No. of authorizing people such as Beihoff are 5,185,684 and 5,206,596 United States Patent (USP) all discloses such device.

It is 5,223,795,5,432 as the patent No. that Blades has used a lot, 455 and 5,434, and the disclosed such method of 509 United States Patent (USP) detects electric arc.It is the fact that half period all comprises the gap at each zero crossing that exchanges (AC) circuit that the device of Blades is based on detected high-frequency noise.In order from other noise source, to distinguish arc discharge, the randomness of the high-frequency signal that the measurement device of Blades is detected and/or broadband characteristics, the patent No. is 5,434, the device that 509 United States Patent (USP) is taught uses the fast rise edge of arc signal as an examination criteria, and the detection short high-frequency burst relevant with interrupted electric arc.

The patent No. of authorizing people such as Zuercher is 5,561,505 U.S. Patent Publication, and a kind of the interchange between cycle in (AC) line current by sensing changes the method that detects arc discharge.Processed then in the difference that exchanges the sample of getting in (AC) same point place in the cycle, to determine whether to occur arc discharge.

Arc discharge feature is the appearance of high-frequency signal on the conductor, and it is different from the frequency (being generally for 60 cycles) of the electric current that conductor originally will carry.Whenever the voltage of crossing over electric arc is reduced to a value that is enough to pilot arc when following, the arc discharge that alternating voltage produces will extinguish, and this computer will rekindle when the voltage of crossing over electric arc surpasses the minimum keep-alive voltage of electric arc.The size of the physical clearance that keep-alive voltage must be crossed over electric arc basically is proportional.

Extinction voltage is usually less than keep-alive voltage.When arc gap was very big, electric arc was intermittent and unstable, and understood oneself and extinguish, and rekindled when conditions permit.When the gap becomes hour, it is more firm lasting that electric arc will become, and oneself is kept at last.When the gap becomes more hour, electric arc will oneself extinguishes by finishing path of current.When the electric arc conduction takes place, on conductor, produce high-frequency signal.

The system of arc discharge appears at the detection that high-frequency signal on the conductor is realized electric arc by supervision in a lot of detection buildings that developed.A kind of such method that detects arc discharge is by the arc detector that can detect signal derivative on the conductor.Typically, such arc detector for example uses that power pack produces some signals, the high-frequency signal on the distribution that these signals representatives are being monitored.Power pack has increased the production cost of arc fault detector and because of the difficulty on the packing that size caused of components and parts, in addition, power pack also has limited high frequency response and relatively poor signal to noise ratio.

Therefore, need provide the arc fault detector of improved signal to noise ratio and improvement high frequency response, such meeting relatively economical on building, and less relatively on the size.

Summary of the invention

Arc fault detector of the present invention can also can combine work with a ground fault circuit interrupter (GFCI) as an independent arc fault circuit interrupter (AFCI), is used for that interruptive current flows to load when electric arc is detected.The composite set that is called arc fault circuit interrupter/ground fault circuit interrupter (AFCI/GFCI) can add arc detection circuitry to be realized by the GFCI to standard, the AFCI/GFCI device is the combination of arc fault and ground fault detector, and it can also prevent the injury to personnel and property of dangerous arc discharge and ground fault condition by interrupt circuit thus.Term " circuit interruption device " is defined as any electronic installation that interruptive current flows to load that is used for, and including, but not limited to the device as ground fault circuit interrupter (GFCI), impregnated testing circuit contact maker (IDCI) or electrical leakage circuit interrupter (ALCI).

In the arc detector disclosed herein, for detect as between the Line To Line, line over the ground between, line is to arc discharge between the neutrality or contact arc discharge, one is monitoring electric current in this at least one conductor with phase conductor or neutral conductor inductor connected in series at least.Signal from this inductor is the derivative (di/dt) that is monitored electric current and is fed to arc detection circuitry that this arc detection circuitry comprises that one has the peak detector of decay, a microcontroller and a circuit interrupter.Series reactor is different from and has part ring or crooked 100 degree or the distribution and the cores hollow or the magnetic material of ring fully, is used to generate the derivative signal of the electric current that flows through conductor, i.e. the di/dt signal.

The present invention can detection line on and/or the arc fault of device load-side.In case handle, the peak amplitude of the di/dt signal that senses is directed to microcontroller, and this microcontroller is analyzed about the existence of arc characteristic for this signal.When confirming to show the signal that has arc discharge in conductor, triggering signal produces, and presents to being used for the interrupt mechanism that interrupt power flows to load.

Microcontroller circuit can be placed on its chip or be placed on the chip that typically is used for present GFCI.When independent chip was used for arc-detection and earth fault protection, it can be by the same power supply power supply that is used for to GFCI power supply, and this power supply other components and parts of returning the GFCI the mechanism that flows to load as interruptive current when fault takes place are powered in addition.This combined method causes owing to bring into play double duty now such as the mechanical part of the GFCI device of tripping relay and mechanical contact close mechanism, so production cost reduces.

Description of drawings

From the following detailed description, claims and accompanying drawing, others of the present invention, feature and advantage will become clearer, and wherein components identical has identical Reference numeral.

Fig. 1 has illustrated the example of contact arc discharge in the conductor of loaded current;

Fig. 2 has illustrated the example of line electric arc between the conductor of two loaded currents;

Fig. 3 is an arc-detection system block diagram in accordance with the principles of the present invention;

Fig. 4 is the block diagram of second embodiment of arc-detection system in accordance with the principles of the present invention;

Fig. 5 is the circuit diagram of arc detection circuitry of the present invention;

Fig. 6 is perpendicular to one another to be placed on the series reactor on the circuit board and the end view of microcontroller;

Fig. 7 is perpendicular to one another to be placed on the series reactor on the circuit board and the top view of microcontroller;

Fig. 8 is the circuit diagram of second embodiment of the arc detection circuitry that combines with ground fault detector.

Embodiment

With reference to figure 3, a kind of arc detection circuitry is disclosed, its be arranged to detect as neutrality over the ground, line over the ground, line is to the arc discharge neutrality and/or the contact arc discharge.Arc-detection is based on using a series reactor to come standby current, to detect in the conductor of at least one alternating current electronic circuit as shown in Figure 3 and Figure 4 whether electric arc taking place.Be used to monitor that the circuit of electric arc comprises the current source (not shown) that is coupled to terminal 12 and 16.Inductor 20 normally with the distribution of lead 18 same specifications, itself and lead 18 series coupled.The inductance of the inductor 20 that is connected in series can be made of distribution, this distribution have with by bend to 15 the degree the formed the same little inductance of lead, up to 100 circles or the formed equally big inductance of lead that bend to 360 degree of multiturn number more, and have hollow core or magnetic core.The inductive part of the inductor 20 that is connected in series depends on the size that is used to operate the required electromotive force of arc detector circuit 24.We find, when having electric arc, one typically has about four complete circles and every circle diameter and provides about 5 volts voltage for 1.8 centimetres series reactor, and any effective series resistance of increase on circuit not.If desired, a clamp circuit 22 can be coupled in parallel to inductor 20, will appear at the maximum voltage at inductor 20 two ends with restriction.The power supply 15 that the phase conductor 14 of leap series reactor upstream is connected with neutral conductor 18 provides the required low-tension supply of various elements of function circuit.Arc detection circuitry 24 by power supply 15 power supplies is connected to be received in the di/dt electromotive force that conductor 34 provides from series reactor 20.More specifically, arc detection circuitry 24 is coupled, and with the di/dt signal of the electric current from inductor 20 reception neutral conductors 18, and analyzes it to determine whether arc discharge exists.When definite arc discharge took place, triggering signal was produced by control circuit suitable in the arc detector circuit 24, and was added to and gives circuit interrupter 28 on the conductor 26.Thereby, the signal that produces based on the current sense inductor that is connected in series 20 when arc detector circuit 24 and when detecting electric arc and taking place, triggering signal is added on the circuit interrupter 28, this circuit interrupter 28 is disconnected to the power supply of load.

In addition, triggering signal can be presented to notification device, luminaire as light-emitting diode (LED) such light emitting devices, loudspeaker or alarm such audio devices, figure or textual number display etc., with the generation of indication electric arc.

With reference to figure 4, show the circuit similar with Fig. 3, and increased second inductor that is connected in series with phase conductor and with this inductor be connected in parallel in order to limit the clamp circuit of its two ends maximum voltage.May be connected in series to phase conductor 14 with the inductor 30 of inductor 20 identical or different specification distributions.The inductor 30 that is connected in series can be made of distribution, this distribution have with by bend to 15 the degree the formed the same little inductance of lead, up to 100 circles or the formed equally big inductance of lead that bend to 360 degree of multiturn number more, and have hollow core or magnetic core.When series reactor comprised conductors that bend to 15 degree or complete circle a part of, the diameter that bends to the part of the conductors of 15 degree or complete circle may be more or less, greatly about 3/4 to 3/2 centimetre.The actual inductance of inductor 30 (with inductor 20) is mainly determined by operation arc detector circuit 24 required output potential sizes, but will be made the impedance minimum that appends on the conductor simultaneously.

And inductor 20,30 can have identical or different inductance value.Therefore, according to the demand of circuit, the inductance of inductor 20 can less than, be equal to, or greater than the inductance of inductor 30.

Arc detector circuit 24 is received in di/dt electromotive force that conductor 35 provides and receives the di/dt signal of electric current the phase conductors 14 from inductor 30 from series reactor 30.Arc detector circuit 24 can be analyzed the di/dt signal, to determine whether to exist arc discharge.In this couple of inductor embodiment, when detecting arc discharge in any signal waveform on conductor 34 or 35, arc detector 24 just produces triggering signal on conductor 26.

Clamp circuit 32 can be coupled in parallel to inductor 30, with the maximum voltage at restriction inductor 30 two ends.In addition, in order to minimize electronic device undesirable coupling effect each other on inductor, microcontroller and the circuit board, inductor, microcontroller and circuit board can quadrature placements like that shown in Fig. 6 (end view) and Fig. 7 (top view).

In another embodiment of the present invention, the series reactor 20 of Fig. 3 is in phase conductor 14, and ground connection is as the return current path.In yet another embodiment of the present invention, the series reactor 20 of Fig. 3 is in phase conductor 14, and neutral conductor is as the return current path.In another embodiment again, series reactor is at least one winding of converter.

With reference to figure 5, show circuit diagram embodiment illustrated in fig. 4.Inductor 20 is connected in series to conductor 18, and inductor 30 is connected in series to conductor 14.From the power supply 15 of phase conductor 14 and neutral conductor 18 received powers required electromotive force is offered arc detector circuit 24.Shown power supply has the electric capacity 41 that is connected in series with diode 42, and this series network is crossed over the upstream of the phase conductor 14 of the inductor 20 that is connected in series and 30 and neutral conductor 18 and is connected.The tie point of capacitor 41 and diode 42 is connected to lead-out terminal by diode 43, and this lead-out terminal is used for needed electromotive force is offered arc detector circuit 24.Be connected between the lead-out terminal of power supply and the neutral terminal is the capacitor 44 in parallel with zener diode 45.

Arc detector circuit 24 comprises two 50,80, two low pass filters 150,180 of peak detector and the microcontrollers 60 that have decay.Each peak detector comprises diode 51,81, and this diode 51 and 81 is connected between the input terminal and neutral conductor 18 and phase conductor 14 of microcontroller 60 at some place in inductor 20,30 downstreams.Conductor 34,35 is passed to peak detector 50,80 to the neutral conductor waveform, the phase conductor waveform that come from inductor 20,30.The parallel circuits that resistor 52,82 and capacitor 54,84 are formed is connected between the cathode terminal and neutral terminal of diode 51,81.The diode 51,81 of each peak detector provides charge path for capacitor 54,84.Each peak detector that has decay provides the signal of representing the derivative (di/dt) of electric current in the conductor 18 (or conductor 14), and is used for broadening by inductor 20, the 30 detected any high-speed pulses that are connected in series.

Conductor 34,35 is also giving low pass filter 150,180 from the signal waveform of neutral inductor 20, phase inductance device 30.Each low pass filter comprise between analog to digital converter (ADC) input that is connected conductor 34,35 and microcontroller 60, be arranged on the resistor 152,182 on the conductor 155,185.Capacitor 154,184 is connected between the ADC input 155,185 and neutral terminal of microcontroller.Resistor 152,182 provides charging and discharge path for the capacitor 154,184 of each low pass filter 150,180.Each low pass filter is created in the voltage at inductor 20,30 two ends by analyzing by the direct current that is used for constituting inductor self distribution (DC) resistance, thereby the signal waveform of representative conductor 18 (or conductor 14) medium and low frequency electric current (i) is provided.Depend on the structure of inductor 20,30, expect to have several milliohms.If the ADC in the microcontroller 60 does not have enough resolution, the output waveform from low pass filter 150,180 that appears on the conductor 155,185 can further be exaggerated.

Microcontroller 60 can be the processor of type that can commercial acquisition, and comprises edge timing logic (can measure interpulse elapsed time) and analog-digital converter circuit (being used for the digitaling analoging signal waveform).As the decision-making on the engineering, can adopt the microcontroller of lower cost, independently the edge timing logic can be connected microcontroller and have between the peak detector 50,80 of decay.The edge timing logic can measuring frequency, cycle or pulse duration.As similar engineering decision, independently analog-digital converter circuit can be connected between microcontroller and the low pass filter 150,180.Have that the microcontroller 60 of edge timing logic and built-in analog-digital converter circuit are current can be in a lot of producers there to be obtained with the price that is lower than 1 dollar.

When peak detector 50,80 and low pass filter 150,180 receive the signal waveform of representing electric arc, microcontroller 60 just produces triggering signal.More particularly, microcontroller 60 is analyzed the signal that receives from peak detector and low pass filter, to determine whether to exist arc discharge, in case when finding that arc discharge exists, just produce triggering signal, present to the circuit interrupter on the conductor 26 28, crystal 62 is provided for the timing of microcontroller work.

The triggering signal that microcontroller produces offers the canopy gate terminal of the TRIAC (triac) 74 in the circuit interrupter 28 by conductor 26.Circuit interrupter 28 comprises the relay that has independently two groups of contacts 71,72 and coil 73.Contact 71 is connected in series with phase conductor 14, and contact 72 is connected in series with neutral conductor.The coil 73 of relay is connected in series to TRIAC, and this series network is connected between phase conductor 14 and the neutral terminal.The canopy gate terminal of TRIAC is connected to conductor 26 comes from microcontroller 60 in order to reception triggering signal by resistor 75.The triggering signal that comes from microcontroller prepares to make the TRIAC conducting, and this TRIAC allows electric current to flow through the coil of relay and open contact 71,72.

With reference to figure 8, show the arc fault detector that combines with ground fault circuit interrupter (GFCI) according to the principle of the invention.The circuit 182 that is commonly called arc fault circuit interrupter/ground fault circuit interrupter (AFCI/GFCI) comprises two power packs that have magnetic core 233,234 and coil 235,236 respectively, they are coupled to integrated circuit (IC) 225, and this integrated circuit can comprise LM1851 that is produced by National Semiconductor (National Semiconductor) or the RA9031 that is produced by Ray Thcon (Raytheon).AC power from a phase conductor 14 and neutral conductor 18 is transfused to power circuit 15, and power circuit 15 generates the power that is used for AFCI/GFCI device internal circuit.

The series circuit of relay coil 218 and SCR224 (silicon controlled rectifier) is connected between power supply 15 and the earth terminal, and the canopy gate terminal of SCR is coupled to the lead-out terminal of SCR flip-flop circuit 216.The output of the lead-in wire 1 of integrated circuit (IC) 225 is as the input of SCR flip-flop circuit 216.

Diode 245 also is joined to coil 235, and this coil 235 is coupled to lead-in wire 2 and 3 by resistor 247 and capacitor 239,249.Lead-in wire 3 also is coupled to the neutral line by capacitor 251.Coil 236 is coupled to the lead-in wire 4 and 5 of IC 225 by capacitor 237,238, and lead-in wire 4 also is coupled to ground.The lead-in wire 6 of IC 225 is coupled to lead-in wire 8 by sensitive resistor 241, and lead-in wire 7 is coupled to ground by time delay capacitor 243.Lead-in wire 8 also is coupled to capacitor 222 and resistor 221 and is connected to power supply 15.

Line side electric conductor, phase conductor 14,10 and neutral conductor 18 arrive the phase conductor and the neutral conductor of load-side by converter 233,234.Relay coil 218 is coupled in order to related with phase conductor and the neutral conductor respectively contact 231,232 of operation, and wherein contact 231,232 is used for making open circuit in detecting the incident of fault.When SCR224 is switched on by the signal from flip-flop circuit 216, relay coil 218 energized.In addition, this circuit comprises the test circuit that contains the instantaneous push-button switch 228 that is connected in series with resistor 230.When switch 228 is pressed, create the interim analogue ground fault from the load phase to the neutral line, with the operation of testing apparatus.

Inductor 20,30 is coupled in series to the downstream of conductor 14,18 and power supply 15 inputs, and conductor 34,35 is connected, so that as described abovely provide the signal of representing derivative (di/dt) electric current in the conductor 14,18 to arc fault detector 24 like that.The microcontroller of arc fault detector can be the part of the IC 225 of element or ground fault circuit interrupter independently.If microcontroller is an element independently, then the triggering signal that produces of microcontroller is fed to SCR flip-flop circuit 216.If microcontroller is the part of IC225, triggering signal is exactly the TRIG-GFCI signal that comes from IC 225.

Here in the description of the disclosed embodiment of the invention, any one or two series reactors 20,30 can be the elementary windings to shared secondary winding, or are connected the independent secondary winding that the signal that is received to present is given microcontroller.Therefore, series reactor provides electric current derivative (di/dt) and becomes the elementary of at least one power pack.Inductor of the present invention disclosed herein can be made of a conductor, this lead have with by bend to 15 the degree the formed the same little inductance of lead, up to 100 circles or the formed equally big inductance of lead that bend to 360 degree of multiturn number more, and have a hollow core or magnetic core.Series inductance is connected in series in the conductor all or part of electric current that flows, there winding independently or the inductance of combination be used to obtain the direct measured value of the derivative of streaming current in the conductor.

Method and apparatus disclosed herein is used to detect the generation of the arc discharge of conductor.From the direct measurement of electric current derivative, obtain improved resolution, signal to noise ratio, derivative accuracy and high frequency response.In the present invention, inductor and line current are connected in series, to measure the derivative di/dt of electric current.By reference inductor on one side electronic device and allow it monitor that the voltage of inductor another side realizes that low noise measures.

Fig. 6 and Fig. 7 have described a front view and a top view with circuit board of series inductance and microcontroller respectively.The fluctuation of line current has produced the magnetic flux that passes series reactor, and inductor is induced flux successively in the electric material around.In response to this magnetic flux, also can induct in the electric material around surface current and sheet electric current.Vertical by the direction that makes inductor with printed circuit board (PCB) with arc fault detector electronic device, circuit board self, be installed on the circuit board or can minimize with surface current and sheet electric current in the electronic device of circuit board coplane.

If it is very high that the derivative di/dt of electric current becomes, a undesirable bigger decline may be arranged at the line voltage at inductor two ends on amplitude.This can be by using one or more diodes, zener diode, avalanche diode, bidirectional trigger diode (DIAC), metal oxide varistor (MOV ' s), high pressure diac (SIDAC), transient absorption device (Transorb), gas discharge tube (GAS TUBE) thereby comes the maximum voltage at clamper inductor two ends to descend and avoided.

At those distribution networks is in the example of two-phase, the 3rd series reactor 40 can be coupled in series to the 3rd conductor 10 with produce at it self two ends with the 3rd conductor in the relevant voltage of derivative of electric current.The output of inductor 40 can be coupled to arc detector 24 by conductor 36.

Use in the device of current measurement at those, can be by saving the space that in a lot of device designs, is of great rarity usually to the series reactor of electric current derivative sensitivity and the elementary combination of current measurement converter.By this way, the same inductor that provides the electric current derivative directly to measure also can play the elementary effect of power pack.

The another kind of mode that obtains current measurement and saving space and cost is to use the resistivity of series reactor self as current sensor, by this way, provide same inductor that the electric current derivative directly measures that the direct measurement of electric current self also can enough auxiliary filtering be provided.

Need the passage susceptibility alternately and the place of current measurement at the same time, two inductors can serve as the elementary of power pack.In this embodiment, each magnetic flux of inducting by two inductors in the converter heart yearn is added or subtracts each other, and still, when subtracting each other, they should not offset mutually fully.

Need at the same time alternately the passage susceptibility and the place of Earth Fault Detection, two inductors can be together elementary as on the earth fault differential converter.In this embodiment, the coupling that is provided by converter can be also can not be unique coupling between two inductors, for given electric current and the magnetic flux of from each of inductor, inducting in the converter heart yearn must cancel out each other fully or almost completely.

Need at the same time alternately the passage susceptibility and the place of Earth Fault Detection, two inductors can be together elementary as on the earth fault converter.In this embodiment, the coupling that is provided by converter can be also can not be unique coupling between two inductors.Therefore, for given electric current and the magnetic flux of from each of inductor, inducting in the converter heart yearn should be added or subtract each other.

Arc detector disclosed herein can make up with the circuit interruption device as ground fault circuit interrupter (GFCI), impregnated testing circuit contact maker (IDCI) or electrical leakage stream contact maker other types such as (ALCI).With the situation of GFCI combination under, arc detection circuitry can be placed on the same silicon chip that typically is used for present GFCI device.In some instances, some lead-in wires of Chang Yong GFCI integrated circuit can be converted for multi-functional operation.AFCI can be by the same power supply power supply to the power supply of circuit interruption device.The method of this combination can cause owing to will bring into play double duty such as the mechanical part of the circuit interruption device of tripping relay and mechanical contact close mechanism, so the production cost reduction.In one embodiment, GFCI can with the AFCI combination of circuits because GFCI can detect arc discharge in some cases, this some situation comprises that electric arc has produced any situation of earth leakage current thus.

Arc fault detector can comprise reset lockout mechanism, and reset lockout mechanism is well-known in the prior art.Reset lockout mechanism is can prevent that the electrical connection between principal vertical line conductor and the load conductor resets under condition that can not operate or neutral line open circuit the situation about existing at arc fault detector.An example of reset lockout mechanism is open in 6,040,967 the United States Patent (USP) in the patent No..

In one embodiment, reset lockout mechanism can be independent of be used for the connection between striping conductor and the load conductor arc fault detector and operate.The circuit interruption device comprises triggering part and reset lockout part; triggering part can be independent of the operation of circuit interruption part; conductive path between striping conductor and the load conductor; wherein circuit interruption partly is used for the sensing fault and disconnects conductive path when sensing fault, and the reset lockout part can partly be worked undesired or has that anti-locking apparatus resets under the situation of neutral line open-circuit condition in circuit interruption.Example with reset lockout mechanism of independent triggers function is open in 6,282,070 the United States Patent (USP) in the patent No..

In another embodiment, arc fault detector can make up with the additional safety device that reverse distribution protection system provides.Oppositely the distribution protection system is operated in the line side and the load-side of device, so that be connected to improperly under the situation of load-side connecting the distribution that installs the line side, the electric arc fault protection that is used for this device is still kept and can be operated.The arc fault detector triggering part is independent of circuit interruption partly works, and wherein this circuit interruption partly is used for the current continuity in the one or more conductive paths of disconnecting apparatus.Can comprise that also the reset lockout part is to prevent that working as circuit interruption partly is to rebulid current continuity under the situation about can not operate or have neutral line open-circuit condition in the conductive path of open circuit.The example of a reverse distribution protection system is open in 6,246,558 the United States Patent (USP) in the patent No..

The front has summarized preferred feature of the present invention more widely so that those skilled in the art's the present invention may be better understood following detailed description.Further feature of the present invention will be described hereinafter, and constitute the theme of claim of the present invention.It should be appreciated by those skilled in the art, they can easily use disclosed notion and specific embodiment, design or change the basis that other structure realizes same purpose of the present invention as being used to, and this other structure does not break away from the spirit and scope of broadest form of the present invention.

Claims (17)

1. be used to detect equipment, comprise having the electric arc on the distribution network of at least one conductor:

The series inductance device is suitable for the conductor series coupled with network, wherein, cross over the series inductance device and produce voltage, this voltage have with described conductor in the relevant monophasic waveform of derivative of electric current;

Electric arc detecting device is coupled with the monophasic waveform that is used to discern the voltage of crossing over the series inductance device when represent arc discharge on the network, and generates arc detection signal from monophasic waveform when monophasic waveform is represented arc discharge on the network; And

Current measuring device is coupled to the series inductance device, is used for measuring the electric current that flows at least one conductor from the monophasic waveform of the voltage of crossing over the series inductance device.

2. equipment as claimed in claim 1, wherein said at least one conductor comprises neutral conductor and phase conductor.

3. equipment as claimed in claim 1, wherein the series inductance device comprises the conductor with 1 to 100 circle.

4. equipment as claimed in claim 1 comprises ground fault circuit interrupter.

5. equipment as claimed in claim 1 comprises impregnated testing circuit contact maker.

6. equipment as claimed in claim 1 comprises electrical leakage stream contact maker.

7. equipment as claimed in claim 1 comprises reset lockout mechanism.

8. equipment as claimed in claim 7, wherein said reset lockout mechanism is independent of electric arc detecting device work.

9. equipment as claimed in claim 1 comprises reverse distribution protection system.

10. be used to detect equipment, comprise having the electric arc on the distribution network of at least two conductors:

The first series inductance device is applicable to first conductor that is coupled in described at least two conductors, to produce the voltage of the leap self relevant with the derivative of electric current in first conductor;

The second series inductance device is applicable to second conductor that is coupled in described at least two conductors, to produce the voltage of the leap self relevant with the derivative of electric current in second conductor;

Electric arc detecting device, the waveform of the voltage of all series inductance devices is crossed in response, has the waveform of representing arc discharge on the network to determine when, and produce arc detection signal when arc discharge exists; And

Current measuring device is coupled to the first and/or second series inductance device, is used for measuring the electric current that flows at described first and/or second conductor from the monophasic waveform of the voltage of crossing over the first and/or second series inductance device.

11. equipment as claimed in claim 10 further comprises:

The 3rd series inductance device is coupled in series to the 3rd conductor of described network, to produce the voltage of the leap self relevant with the derivative of mobile electric current in the 3rd conductor.

12. equipment as claimed in claim 10 comprises ground fault circuit interrupter.

13. equipment as claimed in claim 10 comprises impregnated testing circuit contact maker.

14. equipment as claimed in claim 10 comprises electrical leakage stream contact maker.

15. equipment as claimed in claim 10 comprises reset lockout mechanism.

16. equipment as claimed in claim 15, wherein reset lockout mechanism is independent of electric arc detecting device work.

17. equipment as claimed in claim 10 comprises reverse distribution protection system.

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