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WO1999009422A1 - Systemes de surveillance des arcs electriques - Google Patents

Systemes de surveillance des arcs electriques Download PDF

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Publication number
WO1999009422A1
WO1999009422A1 PCT/US1998/016521 US9816521W WO9909422A1 WO 1999009422 A1 WO1999009422 A1 WO 1999009422A1 US 9816521 W US9816521 W US 9816521W WO 9909422 A1 WO9909422 A1 WO 9909422A1
Authority
WO
WIPO (PCT)
Prior art keywords
arc
electric
monitoring
output
detector
Prior art date
Application number
PCT/US1998/016521
Other languages
English (en)
Inventor
Michael T. Parker
James J. Keenan
Luc Pierre Benoit
Howard M. Ham, Jr.
Original Assignee
Hendry Mechanical Works
Ham, Margaret, F.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hendry Mechanical Works, Ham, Margaret, F. filed Critical Hendry Mechanical Works
Priority to EP98943182A priority Critical patent/EP1004031A4/fr
Priority to US09/762,562 priority patent/US6772077B1/en
Priority to AU91031/98A priority patent/AU9103198A/en
Publication of WO1999009422A1 publication Critical patent/WO1999009422A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R23/00—Arrangements for measuring frequencies; Arrangements for analysing frequency spectra
    • G01R23/16—Spectrum analysis; Fourier analysis
    • G01R23/18—Spectrum analysis; Fourier analysis with provision for recording frequency spectrum
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R29/00—Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
    • G01R29/08—Measuring electromagnetic field characteristics
    • G01R29/0807—Measuring electromagnetic field characteristics characterised by the application
    • G01R29/0814—Field measurements related to measuring influence on or from apparatus, components or humans, e.g. in ESD, EMI, EMC, EMP testing, measuring radiation leakage; detecting presence of micro- or radiowave emitters; dosimetry; testing shielding; measurements related to lightning
    • G01R29/0842—Measurements related to lightning, e.g. measuring electric disturbances, warning systems

Definitions

  • the technical field of the invention includes methods and apparatus for monitoring, detecting, indicating, evaluating and signaling electric arcs or sparks.
  • the chaotic electromagnetic emanations manifesting themselves as electric arcs or sparks are closely Linked to matter, wherein electromagnetic interactions bind electrons to nuclei in atoms and molecules and wherein the fundamental unit of electromagnetic radiation is the photon.
  • spectra of electric arcs and sparks extend practically from DC through the entire radio- frequency spectrum and through microwave, infrared and light spectra.
  • Useful exploitations of the electric arc and spark phenomenon include the electric arc lamp, electric welding, the electric-arc-type of metallurgical furnace, the arc type of ion generator in satellite thrusters and for propulsion in outer space, the spark-plug- type of ignition in internal combustion engines, and electric spark ignition in gas appliances.
  • electric arc monitors would be useful in garages, automobile or motorcar repair facilities, gasoline (British "petrol”) storage or dispensing facilities and in other areas where accidental electric arcing can cause disastrous explosions.
  • fuses and circuit breakers are capable of preventing serious overload conditions, but they are generally ineffective to prevent electrical fires and other d ⁇ jnage from accidental arcs and sparks which typically generate enough heat for a fire at electric current levels below the level at which the fuse will blow or the circuit breaker will trip.
  • Reliable arc monitoring would thus be highly desirable in a large number and variety of electrical circuits. These are, of course, only representative examples of fields where reliable arc or spark monitoring could be useful.
  • a frequency selective arc detection system of a subsequently filed prior-art application appears as a typical representative of the prior-art approach to arc detection. It accordingly presents a variety of approaches to arc detection that mainly look at frequencies in the upper kilohertz range, such as from 100 kHz to one megahertz. This, however, covers not only major portions of the public A.M. radio broadcast band, also known as “long-wave” and “medium-wave” broadcast bands in some countries, but also the kind of control or security systems radio frequency band referred to in the above mentioned WO90/04278 reference. Depending on location, one thus had to contend with dozens of extraneous signal interferences.
  • Fractal geometry in effect is a manifestation of the fact that the natural world does not conform to an Euclidean type of geometry.
  • Euclidean geometry is based on characteristic sizes and scaling. The natural world is not limited to specific size or scaling. Euclidean geometry suits man-made objects, but cannot realistically express natural configurations. Euclidean geometry is described by formulas, whereas the mathematical language of natural phenomena is recursive algorithms. Such recursiveness is an expression of nature throughout destructive if not chaotic influences, manifesting itself, for instance, in a persistent invariance against changes i.i size and scaling, generating almost endless, repetitious patterns of self- similarity or self-affinity .
  • I a ⁇ arc signature current flowing in the monitored circuit where an electric arc occurs at the moment
  • I n current induced by the arc signature in a moni- tored neighboring circuit where no arc has occurred at the moment
  • M mutual inductance
  • Z n impedance of said neighboring circuit
  • f frequency
  • ELF extremely low frequencies
  • an aspect of the subject invention accordingly exploits the discovery that electric arcs are fractal phenomena not only in the visible luminous portion of their electromagnetic radiation, as heretofore thought, but in fact are fractal phenomena all the way down to the extremely low frequency band of their electromagnetic emanation into space or along wires of the circuit where the particular arc occurs. Since all essential information that signifies "arc" is thus contained in each fractal subset, it is sufficient for arc monitoring purposes to monitor a fractal subset of the arc's electromagnetic emanation.
  • the selection of the monitoring frequency band for each purpose is liberated from prior-art con- straints and can truly be the result of an optimum tradeoff in sensitivity, speed of detection, prevention or rejection of false signals, desired length of travel and mode of transmission of the arc signature from the arc to the monitoring circuit in different environments.
  • the subject invention resides in a system of monitoring an electric arc having an arc signature typified by a wideband range of frequencies of a chaotic nature in a monitored circuit, and, more specifically, resides in selecting a fractal subset of the arc signature characterized by relatively long travel along the monitored circuit, and monitoring that fractal subset of the arc signature.
  • the expression "relatively” in this context refers to the fact that the length of possible travel of the arc signal is inversely proportional to the frequency of the arc signature. In this respect, reference may be had to the familiar algebraic equation for electric current:
  • a related benefit of an embodiment of the invention can be seen; namely, that a selection of the lowest frequency or longest wavelength fractal in effect amounts to a selection of the longest survivor of the different fractals of the arc signature traveling along the monitored circuit.
  • the monitored circuit itself thus performs the function of a low-pass filter for the arc detection monitor.
  • embodiments of the invention permit arc monitoring at considerable distances from the occurrence of arcs in the circuit, which is useful in practice for several reasons, including the capability of surveying large circuits, and the convenience of providing central arc detection monitoring stations for several different circuits.
  • embodiments of the invention induce less spurious signals through cross-induction in neighboring circuits than arc signatures having higher frequencies.
  • Low frequency fractals more effectively avoid false alarms from mutual inductance among neighboring circuits than arc signatures at higher frequencies.
  • embodiments of the invention not only permit arc monitoring at considerable distances from the occurrence of arcs in a monitored circuit, but also avoid false alarms in neighboring monitored circuits.
  • the electric arc is detected from a fractal subset o ' the arc signature at frequencies below 30 kHz.
  • VLF very low frequency
  • a presently preferred embodiment of the invention restricts fractal subsets from which the electric arc is detected to the ELF (extremely low frequency) band which in that IEEE Standard Dictionary is defined as extending from 3 Hz to 3 kHz.
  • Another embodiment of the invention restricts monitored fractals to arc signature frequencies below the voice frequency band (vf) defined in that IEEE Standard Dictionary as extending from 200 Hz to 3500 Hz.
  • vf voice frequency band
  • a further embodiment of the invention restricts monitored fractal subsets to arc signature frequencies below a first harmonic of a standard line frequency in alternating-current power supply systems.
  • an apparatus for monitoring an electric arc having an arc signature typified by a wideband range of frequencies of a chaotic nature in a monitored circuit comprises, in combination, an electric filter having an input coupled to that arc, having a passband corresponding to a fractal subset of the arc signature characterized by relatively long travel along the monitored circuit, and having an output for that fractal subset of arc signature.
  • Such apparatus includes a chaotic wideband signal detector having a detector input for that fractal subset of the arc signature coupled to the output of the electric filter.
  • the invention resides in a method of monitoring an electric arc having an arc signature extending over a wideband range of frequencies of a chaotic nature in a monitored circuit.
  • the invention according to this aspect resides, more specifically, in the improvement comprising, in combination, processing portions of the arc signature in two paths out of phase with each other, and monitoring the electric arc from such out of phase portions of the arc signature.
  • the invention resides in apparatus for monitoring an electric arc having an arc signature typified by a wideband range of frequencies of a chaotic nature in a monitored circuit.
  • the invention resides, more specifically, in the improvement comprising, in combination, an electric filter having an input coupled to the arc, having a passband corresponding to portions of the arc signature, and having an output for such portions of arc signature, an inverting amplifier having an input connected to the output of the electric filter, and having an amplifier output, a non-inverting amplifier having an input connected to the output of the electric filter, having an amplifier output, and being in parallel to said inverting amplifier, and a chaotic wideband signal detector having a detector input coupled to the amplifier outputs of the inverting and non-inverting aaiplifiers .
  • the invention resides in a method of monitoring an electric arc having an arc signature extending over a wideband range of frequencies of a chaotic nature in a monitored circuit, and, more specifically, resides in the improvement comprising, in combination, treating the arc signature as a modulated carrier having a modulation indicative of the electric arc, and monitoring the electric arc by monitoring a modulation of the modulated carrier.
  • the invention resides in apparatus for monitoring an electric arc having an arc signature typified by a wideband range of frequencies of a chaotic nature in a monitored circuit, and, more specifically, resides in the improvement comprising, in combination, a modulated carrier detector having an arc signature input and a carrier modulation output.
  • the invention resides in apparatus for monitoring an electric arc having an arc signature typified by a wideband range of frequencies of a chaotic nature in a monitored circuit, and, more specifically, resides in the improvement comprising, in combination, combined modulated carrier detectors having arc signature inputs and a combined carrier modulation output.
  • the invention resides in a method of monitoring occurrence of sparks aboard aircraft, comprising, in combination, continually monitoring an occurrence of sparks at a first location aboard the aircraft, continually monitoring an occurrence of sparks at a second location aboard the aircraft distant from that first location, and establishing in response to such monitoring a record of sparks occurring at the first location and a record of sparks occurring at the distant second location aboard the aircraft.
  • spark is used generically in this respect to cover sparks and electric arcs interchangeably, inasmuch as there may be sparking aboard aircraft that is not of an electrical origin, but that still has the potential of igniting fuel vapors and causing other damage, such as more fully disclosed below.
  • Fig. 1 is a polar coordinate representation of an electric arc signature spectrum in terms of wavelength and illustrates selection of a fractal subset for arc monitoring pursuant to an embodiment of the invention
  • Fig. 2 is a block diagram of an electric arc monitoring system pursuant to an embodiment of the invention
  • Fig. 3 shows gain vs. frequency graphs illustrating a presently preferred embodiment of the invention
  • Fig. 4 is a schematic of circuitry that may be used in the. system of Fig.
  • FIG. 5 is a schematic of another circuitry that may be used in the system of Fig. 2 or otherwise for monitoring an arc according to an embodiment of the invention
  • Fig. 6 is a schematic of a further circuitry that may be used in the system of Fig. 2 or otherwise for monitoring the arc also according to an embodiment of the invention
  • Fig. 7 is a circuit diagram of an optical indicator of possible or actual arcing that can be used at various stages in the systems of Figs. 2, 4, 5 and 6, according to a further embodiment of the invention
  • Fig. 8 is a schematic view of a spark monitoring system in and for aircraft pursuant to an embodiment of the invention.
  • the accompanying Fig. 5 is a schematic of another circuitry that may be used in the system of Fig. 2 or otherwise for monitoring an arc according to an embodiment of the invention
  • Fig. 6 is a schematic of a further circuitry that may be used in the system of Fig. 2 or otherwise for monitoring the arc also according to an embodiment of the invention
  • Fig. 7 is
  • FIG. 1 shows the workings of the invention in terms of a logarithmic spiral.
  • arc signature spectra traditionally have been plotted in Cartesian coordinates and in terms of frequency. To a large extent, thinking and plotting in terms of frequency was justified, since the frequency of the arc signature is largely independent of the medium through which it travels, while the wavelength of the arc signature depends more directly on the traversed medium.
  • ammonite shell had a chambered structure wherein internal chambers were partitioned off by septa, which were a series of spaced plates which were spaced most closely at the center of the shell and the spacing of which increased logarithmically along the growth spiral of the shell. Accordingly, the size of the chambers between adjacent septa increased logarithmically along the growth spiral.
  • Fig. 1 indicates specific portions of the electromagnetic arc signature in terms of frequency, including the following frequency bands t ⁇ ith increasing progression:
  • GHz gigahertz
  • MHz megahertz range wherein arc signature detection has been conducted by the prior art and wherein extraneous signals from television broadcasts and radio signals abound
  • 100 kHz the one-hundred kilohertz range wherein arc signature detection also has been conducted extensively by the prior art and wherein radio broadcast signals abound
  • 30 kHz a lower limit of prior-art arc detection
  • VLF "very low frequency" defined as extending from 3 kHz to 30 kHz by the above mentioned IEEE Dictionary.
  • ELF "extremely low frequency” defined as extending from 3 Hz to 3 kHz by that IEEE Dictionary
  • vf voice frequency within the range of 200 to 3500 Hz according to that IEEE Dictionary
  • It "line frequency”, i.e. 50 Hz in European Systems, or 60 Hz in American systems.
  • Fig. 1 shows the statistical self-similarity of logarithmic fractal subsets of the depicted arc signature. Summarizing the .ammonite analogy, the logarithmic nature of the depicted arc spectrum is seen not only in the evolution of the growth spiral 10, but also to the logarithmically progressing length of frequency intervals 12 in terms of wavelength, individually delimited by what corresponds to the above mentioned septa of the ammonite shell.
  • Fig. 1 also depicts the inverse frequency or 1/f dependency of electric arc signatures in s terms of amplitude. In the case of Fig. 1, this shows as an amplitude increasing with wavelength to a value of a,-,,.. This is another indication of the fractal nature of electric arcs.
  • fractal subset As the Leitmotif in music, such fractal subset may have the nature of an attractor as a limit figure of fractal iteration, as more fully described below.
  • a preferred embodiment of the invention detects the electric arc from a fractal subset below 30 kHz of the wideband range of arc signature fre-quencies .
  • VLF very low frequency
  • an embodiment of the invention restricts fractal subsets from which the electric arc is detected or in which the electric arc is monitored to the ELF (extremely low frequency) band which according to The New IEEE Standard Dictionary of Electrical and Electronics Terms, Fifth Edition (The Institute of Electrical and Electronics Engineers, 1993) is defined as extending from 3 Hz to 3 kHz.
  • Another embodiment of the invention restricts monitored fractals to arc signature frequencies below the voice frequency band (vf) defined in that IEEE Standard Dictionary as extending from 200 Hz to 3500 Hz.
  • a further embodiment of the invention restricts monitored fractal subsets to arc signature frequencies below a first harmonic of a standard line frequency in alternating-current power supply systems.
  • An embodiment of the invention even selects the monitored arc signature fractal subset from a frequency band on the order of a standard line frequency ( f) in alternating-current power supply systems.
  • the invention in its embodiments can select the fractal that will give the best overall perforxiance in a given situation, all the way to the maximum arc signature amplitude of a,. ⁇ for optimum signal-to-noise ratio; with the signal in such case being the 1/f-noise of the arc which we have designated above as ⁇ réelle - noise.
  • selecting from the arc signature a fractal that yields an amplitude of a,- ax or an amplitude comparable thereto has another advantage where cross-induction of arc signatures could be a problem.
  • several electric circuits are monitored for electric arcs by several corresponding arc detectors, and assume that an arc occurs in one of these circuits and that the arc detector pertaining to that circuit is to respond thereto.
  • a preferred embodiment of the invention minimizes if not practically eliminates the prior-art danger of false alarms from cross-induction among independently monitored neighboring circuits.
  • Fig. 2 shows an electric conductor 20 of electric circuitry 21 wherein an electric arc 22 occurs.
  • the circuitry 21 may be part of a telephone exchange or may be another one of a large variety of electric circuits or loads, including the following examples:
  • a reliable spark monitoring system is therefore highly desirable, if not potentially indispensable in cutting-edge internal combustion engine technology.
  • the loeid at 21 may for instance be a robotic or other spot welding apparatus.
  • the electric arc monitor could supervise the spot welding process and could signal when substandard welds are being produced by intervening arcing.
  • an electric spark monitor would indicate when the igniter is in need for replacement, before breakdown and costly outage occur.
  • electric arcs are used in ionizers, such as ammonia arc and other ion generators that are coming into use in satellite thrusters and in propulsion systems in outer space, such as for restabilizing satellites in geostationary orbits or for propelling satellites and space probes on their journey.
  • an electric arc monitor would be useful in research, development, maintenance and operation of such ion generators.
  • machinery, circuitry or apparatus at 21 that produces normal sparks in its operation could be monitored for detrimental arcing.
  • the invention selects a fractal subset 16 of the signature of the electric arc 22 for the purpose of arc detection. In such selection the invention aims for a relatively long travel of arc signature along the monitored circuit 20 (distance between arc 22 and pickup 23), and for low cross- induction among neighboring circuits, including the monitored circuit 20.
  • the fractal subset of arc signatures is selected in a freqr.ency band below 30 kHz, where arc signature amplitudes are higher, arc signature travel along wires (20) is longer, and arc signal cross-induction among separately monitored neighboring circuits (21, 30) is lower, than at higher frequencies.
  • the invention detects the electric arc 22 from the fractal subset 16 of the arc signature.
  • aspects of the invention herein disclosed can be applied to frequency bands other than the preferred ELF (extremely low frequency) band, and the subject applicants have built models of the circuitry shown in Fig. 2 not only for the ELF band, but also for operation at several kilohertz, as well as in the 10 to 20 kHz region.
  • the narrower frequency band 15 or fractal subset 16 is selected where there are less extraneous signals than in a remainder of the wideband range of frequencies of the arc signature.
  • the non-linear processor 42 may, for instance, include an FM demodulator which at output 43 produces a signal in response to such chaotic variations of phase or frequency as occurring in an electric arc signature.
  • the combined modulated carrier detectors may include different kinds of modulated carrier detectors, such as an FM detector at 42 and an AM detector at 46 connected in series.
  • Response characteristics of the type shown in Fig. 3 at 51 may, for instance, be realized by operational amplifier type of bandpass filters, quartz filters, LC .. resonance filters, and other circuitry accomplishing such kind of function.
  • the characteristic 51 displays minimal response to any fundamental frequency passed by the lowpass filter 25, such as in the band 15, and, in our example, displays response only to frequencies of the picked-up arc signature fractal subset 16 whose sum or other modulation product falls in the passband range 18 of the frequency-converted arc signature signal 17.
  • Bandpass filter 144 will pass only frequency components that are within a few hertz on either side of the passband, such as 80 Hz, for instance. This delivers a sample of the higher frequencies in the output of the multiplier 142 to the next stage 46.
  • this stage 144 is only going to pass signals which have been boosted in the mixing process to frequencies higher than such cutoff. This in effect prevents non-chaotic signals from passing this stage.
  • the multiplier or stage 142 should not pass any of the original input frequencies (e.g. below 50 Hz) if there is no direct-current at either input 127 and 227, and if such multiplier or stage 142 is perfectly efficient. However, neither assumption is always correct in practice. Accordingly, use of the higher frequency passband filter 144 provides effective rejection of the unprocessed or unmixed original frequencies.
  • Such a filter may be split in two, providing between the terminal 26 a first filter for the inverting amplifier 242 and a second filter for the non-inverting amplifier 342.
  • Filter 25 may be similarly split in or for the embodiment of Figs. 4 and 5 to provide separate filter paths from the input terminal 26 to detectors 412 and 413 or multiplier or frequency converter inputs 127 and 227.
  • the mixer 442 may be composed of conventional components, such as of two diodes interconnected in an OR-element configuration between input terminals at 421 and 422 and the previously mentioned output terminal 43.
  • the component 442 may, however, include a modulator, such as the above mentioned modulator 142.
  • the circuit 244 may include a bandpass filter corresponding to the bandpass filter 4426 or 144 mentioned above with respect to Figs. 2 to 5.
  • the component 244 in Fig. 6 may include a standard IF amplifier, such as the commercially available 440 Hz IF amplifier to name an example.
  • the embodiments of Figs. 2 to 5 thus share with each other a feature according to which the narrow-band extraneous signals, such as mentioned above or shown in Fig. 3 at 52 in a fractal subset 16 or other fractal of the arc signature are diminished in energy relative to a remainder of such fractal subset portion before detection of an electric arc 22 from such fractal subset.
  • the fractal subset 16 is subjected to a frequency transformation, such as shown in Fig.
  • a fractal subset of the arc signature portion may be treated as a modulated carrier having a modulation indicative of any electric arc 22, and such electric arc may be detected from such modulated carrier for further rejections of extraneous signals.
  • the demodulator system disclosed above with respect to Fig. 2 can also be used in the embodiment of Fig. 6, the terminal 47 of which may be the same as the input terminal 47 of the time and level sensing and alarm circuitry 48 - 50 in Fig. 2, with respect to which various systems of modulation have been mentioned above.
  • indications of the progress of the signal through arc monitoring circuitry may be accomplished with three similar functional blocks or differential indicators of which a prototype is shown in Fig. 7 at 54.
  • Such circuit 54 includes an operational amplifier 55 having its non-inverting input 56 connected to a circuit input 57 through a lowpass filter and RC timing component 58 to prevent response to short-term transients.
  • the inverting input 60 of that op amp is connected to comparator level resistors 61 and 62.
  • That op amp 55 has a feedback circuit 64 which may include a feedback capacitor or other impedance 65 and a unidirectional current conducting device, such as shown at 66, for such purposes as noise reduction, prevention of premature or excessive switching.
  • the op amp 55 may be of the type LM35BAN.
  • the indicator circuit 54 includes light-emitting diodes or LEDs 68 and 69 switched by transistors 71 and 72 biased through resistors, including series resistors 73 and 74 and a pair of resistors 75 and 76.
  • Transistors 71 and 72 may, for instance, be of the type 2N2222.
  • a resistor 78 connects transistor 72 to the output of the comparator op amp 55.
  • Transistor 71 is normally biased ON through the series-connected resistors 75 and 76. This turns ON the first LED 68 which, for instance, may be a green LED.
  • the second LED 69 may be a red LED.
  • the second transistor 72 and thus the red LED 69 are biased off at that point.
  • signals having frequencies in the monitored -fractal subset or other band of interest occur at the output 43 of the non-linear processor 42 or modulator 142 or mixer 442 in the embodiments of Figs. 2, 4 and 5, and thereby at the input 57 of the circuit 54 connected thereto, the output of the comparator 55 goes positive, turning the transistor 72 ON, and shutting the transistor 71 OFF.
  • This turns 'the red LED 69 ON and turns the green LED 68 OFF, thereby indicating to an observer that frequencies in the band of interest for arc detection are occurring, such as through a disturbance that may be, but not necessarily is indicative of an electric arc 22.
  • Such display stage 54 then indicates through its red LED an occurrence of wideband signals in a bandwidth of interest, such as in the monitored fractal subset; a well-known criterium of arc signatures. Gain adjustments in such circuit 54 again may give a user a 'qualitative feel' with respect to picked-up wideband signals at that point by gauging the mixture the red and green LED colors .
  • a wideband signal is not an arc signature unless it displays chaotic frequency changes.
  • the circuitry shown in Fig. 7 may be used as a final display stage in the monitoring circuits shown in Figs. 2, 4, 5 and 6.
  • the input terminal 57 of the circuit 54 may be connected to the alarm output terminal 49 shown in Fig. 2.
  • Fig. 7 thus provides a prewarning of a possible electric arc; preferably in two or three stages, culminating in a display of an occurrence of a chaotic wideband signal in a bandwidth of the monitor d fractal subset, or otherwise in a bandwidth of interest such as described above in connection with these Figs. 2, 4, 5, 6 and 7.
  • Principles and circuitry herein disclosed may be employed in various arc monitoring functions, such as mentioned above.
  • the system 80 continually monitors an occurrence of sparks at a first location aboard the aircraft, continually monitors an occurrence of sparks at a second location aboard the aircraft distant from such first location, and establishes in response to such monitoring a record 82 of sparks occurring at that first location and a record 83 of sparks occurring at the distant second location aboard the aircraft 81.
  • the spark monitoring system 30 aboard aircraft 81 may include a spark monitor 92 at a first location aboard the aircraft, having a first spark signal output 102, a spark monitor 93 at a second location aboard the aircraft distant from that first location, having a second spark signal output 103, and a spark signal recorder 97 connected to such first and second spark signal outputs.
  • an embodiment of that aspect of the invention continually monitors an occurrence of sparks at a third location aboard the aircraft distant from the first and second locations, and establishes the desired record as a record 82 of sparks occurring at the first location, a record 83 of sparks occurring at the second location, and a record 84 of sparks occurring at the third location aboard the aircraft.
  • the spark monitoring system 80 may include a spark monitor 94 at a third location aboard the aircraft distant from the first and second locations, having a third spark signal output 104 connected to the spark signal recorder 97.
  • Fig. 8 also has a spark monitor 95 at a fourth location aboard the aircraft distant from the first, second and third locations, having a fourth spark signal output 105 connected to the spark signal recorder 97, and a spark monitor 96 at a fifth location aboard the aircraft distant from the first, second, third and fourth locations, having a fifth spark signal output 106 connected to the spark signal recorder 97 of the system 80.
  • the embodiment of Fig. 8 has the first spark monitor 92 in a frontal area of the aircraft 81 where an electric drive for retracting and deploying a nosewheel or where other electrical equipment may be located.
  • Fig. 8 also shows a spark monitor 94 at the location of a central fuel tank, and spark monitors 93 and 95 at the location of integral wing fuel tanks.
  • the embodiment of Fig. 8 moreover, has a spark monitor 96 at the location of an underfloor cargo or other freight compartment. That much for illustrated examples of spark monitor locations. Deployment and location of spark monitors pursuant to the subject invention logically depends not only on concerns of manufacturers and operators, but also on the nature of the aircraft. Less spark monitors typically would be provided in a small aircraft than in a large airplane. Other desirable locations of spark monitors include main wheel carriage retractor positions, electric cable channels, distribution systems, and other potential sparking areas. In fact, pursuant to a preferred embodiment of the currently disclosed aspect of the invention, the system 80 monitors occurrence of sparks at a multitude of different locations aboard the aircraft, and establishes a record of sparks occurring at such multitude of different locations aboard the aircraft 81.
  • an alarm condition is established in response to occurrence of sparks at at least one of the mentioned locations.
  • Such alarm condition may be visual, audible or in any other form.
  • An alarm device may be connected to at least one of the spark signal outputs 102 to 106.
  • Fig. 8 shows a bank of signal lights 98 for signalling detection of sparks at any of the illustrated locations. Alarm conditions signalled by such lights or any other alarm conditions within the scope of the invention may be established during the flight of the aircraft.
  • the recorder 97 and the signalling equipment 98 may be located aboard the aircraft 81.
  • alarm conditions may be displayed to the pilot or pilots during flight or may be established at the end of a flight of that aircraft.
  • the recorder 97 will be a so-called "black box" which in the field of aviation refers to sealed shock-proof units designed to survive an aircrash to be recoverable from the wreck for an inspection of the probable cause of the crash.
  • a spark detector "black box" aboard TWA Flight 800 would have gone a long way to indicate the cause of that tragedy and to make aircraft and air travel safer for the future. While such is within the scope of the invention, the main object of the invention is, however, to prevent tragedy effectively. In reality, sparking due to defective conditions will go on for weeks, if not months, before the condition has deteriorated to, or has otherwise reached the point, where an explosion or similar disaster can occur under a coincidence of peculiar circumstances including sparking as one of the factors. Accordingly, a preferred embodiment of the invention est.ablish.es a record of occurring sparks on a chart 100 which may be processed in the spark signal recorder 97. Practice of the invention is not limited to any specific recording technique or recorder, but Fig.
  • FIG. 8 shows a chart recorder having for instance a chart supply 101 and a chart drive 107 for driving the chart in the direction of an arrow 108.
  • Conventional recording devices 112, 113, 114, 115 and 116, connected to spark signal outputs 102, 103, 104, 105 and 106, respectively, may be employed for establishing records 82, 83, 84, 85 and 86, respectively, of sparks occurring at the different locations and detected by spark monitors 92, 93, 94, 95 and 96, respectively.
  • continuous operation of recorder 97 throughout the flight is within the scope of the invention, an embodiment thereof prefers the recorder to run only when there is at least one spark sensed at any of the locations 92, 93, 94, etc.
  • Fig. 8 symbolically shows a logic OR-element 109 as a device for starting the recording medium drive 107 only in response to any one or more detected sparks.
  • the date and time of occurrence of each sparking preferably is recorded, such as on the chart 100 itself.
  • a timing track 117 may be provided on the chart 100.
  • Conventional time keeping and signal generating apparatus 118 may be used for this purpose in combination with the remainder of the system, such as in conjunction with a time signal recording device 119 connected to the time signal generating apparatus 118.
  • the recording medium need not necessarily be a chart, but may be a magnetic, thermoplastic or other recording m&dium.
  • arc signatures of electric arcs picked up by any of the detectors 92 to 96 may be processed in two paths out of phase with each other, and occurrence of electric arcs may be continually monitored from such out-of-phase portions of the arc signature.
  • an electric filter 25 having an input 26 coupled to any of the arc detectors 92 to 96 has a passband corresponding to portions of the arc signature, and has an output 27 for such portions of arc signature.
  • An inverting amplifier .'242 has an input 327 connected to the output 27 of electric filter 25, and has an amplifier output 241.
  • a non-inverting amplifier 342 has an input 427 connected to the output 27 of electric filter 25, and has an amplifier output 422.
  • the non-inverting amplifier is in parallel to inverting amplifier 242.
  • a chaotic wideband signal detector 422 has a detector input coupled to amplifier outputs 421 and 422 of the inverting and non-inverting amplifiers for arc detection at 92 to 96, for instance.
  • arc signatures of electric arcs may be treated as a modulated carrier having a modulation indicative of such electric arcs, and occurrence of these electric arcs at 92 to 96 may be continuously monitored by monitoring a modulation of such modulated carrier. In practice, this will avoid response of arc detectors to signals other than arc signatures.
  • a preferred embodiment of the invention monitors electric arcs by monitoring a fractal subset of arc signatures of electric arcs, such as at 92 to 96 in the embodiment of Fig. 8.
  • Application of such fractal concept permits the designer to choose the arc detection frequency band that is least likely to be affected by other frequency spectra occurring aboard aircraft 81 or otherwise.
  • Any and all other features herein disclosed for various arc detectors and monitors may also be used in the system 80 shown in Fig. 8 and in further developments thereof within the scope of the invention.
  • non-electrically generated sparks such as sparks resulting from mutual impingement of metallic parts of the aircraft, may be detected from spark emanations other than accompanying radio frequency spectra or "signatures".
  • optical emanations of sparks may also be detected by optoelectro- nic transducers located near equipment where sparking may occur.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Mathematical Physics (AREA)
  • Testing Relating To Insulation (AREA)
  • Electric Propulsion And Braking For Vehicles (AREA)
  • Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)

Abstract

On effectue la surveillance d'arcs électriques en tirant profit de la découverte selon laquelle les arcs électriques sont des phénomènes fractals dans lesquels toute l'information essentielle qui signifie 'arc' est contenue dans chaque sous-ensembles fractal. Ces sous-ensembles fractals sont répartis de façon logarithmique sur tout le spectre de l'arc. La surveillance des arcs s'effectue de façon avantageuse sur un sous-ensemble fractal (16) d'ordre logarithmique faible, où l'amplitude est supérieure conformément à la caratéristique l/f des arcs électriques, où l'induction croisée parmi les circuits voisins est inférieure et où le trajet entre l'arc (12) et l'enregistrement (23) de la signature de l'arc est plus long qu'aux fréquences élevées habituelles pour la détection des arcs électriques. La transformation en sous-ensembles fractals (17) réduit le risque des fausses alarmes. Les parties signatures des arcs peuvent être traitées en dehors des trajets de phases (242, 342) ou traitées comme porteuses modulées (42) en vue d'une surveillance. Les avions peuvent être équipés de systèmes de détection d'étincelles (80) qui enregistrent (82-86) l'apparation d'étincelles dangereuses en différents endroits (92-96) à bord de l'avion (81).
PCT/US1998/016521 1997-08-14 1998-08-10 Systemes de surveillance des arcs electriques WO1999009422A1 (fr)

Priority Applications (3)

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EP98943182A EP1004031A4 (fr) 1997-08-14 1998-08-10 Systemes de surveillance des arcs electriques
US09/762,562 US6772077B1 (en) 1998-08-10 1998-08-10 Electric arc monitoring systems
AU91031/98A AU9103198A (en) 1997-08-14 1998-08-10 Electric arc monitoring systems

Applications Claiming Priority (2)

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USPCT/US97/14497 1997-08-14
PCT/US1997/014497 WO1999009424A1 (fr) 1997-08-14 1997-08-14 Systemes de controle pour arcs electriques

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JP (1) JP2001518603A (fr)
AU (2) AU763046B2 (fr)
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US6400258B1 (en) 2000-01-19 2002-06-04 Hendry Mechanical Works Electric arc monitoring systems
WO2005029666A1 (fr) * 2003-09-15 2005-03-31 The Boeing Company Systeme et procede de detection a distance de formation d'arcs dans un systeme d'alimentation
US9557365B2 (en) 2013-03-14 2017-01-31 Hubbell Incorporated Apparatuses, systems and methods for detecting corona
CN110568329A (zh) * 2019-09-16 2019-12-13 珠海格力电器股份有限公司 电弧检测方法、家用电器及计算机可读存储介质
CN112363021A (zh) * 2020-11-13 2021-02-12 重庆大学 一种分布式线路故障检测与定位系统及方法

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WO1999009424A1 (fr) * 1997-08-14 1999-02-25 Hendry Mechanical Works Systemes de controle pour arcs electriques
KR101139918B1 (ko) * 2010-08-19 2012-04-30 주식회사 캔티스 아크 및 전자파 측정 장치
CN106707094B (zh) * 2015-11-12 2019-03-15 沈阳工业大学 低压供配电线路电弧故障的分类识别方法
EP3616822A1 (fr) * 2018-08-30 2020-03-04 Fronius International GmbH Procédé de détermination d'une influence perturbatrice entre des circuits de soudage d'une installation de soudage
EP3616823A1 (fr) 2018-08-30 2020-03-04 Fronius International GmbH Procédé de compensation d'une influence perturbatrice d'un courant de soudage par une autre source de courant de soudage
CN109490934B (zh) * 2018-12-19 2022-11-25 上海平高天灵开关有限公司 一种真空灭弧室x射线检测平台

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6400258B1 (en) 2000-01-19 2002-06-04 Hendry Mechanical Works Electric arc monitoring systems
EP1257836B1 (fr) * 2000-01-19 2011-07-27 Telect, Inc. Systèmes de surveillance d'arcs électriques
WO2005029666A1 (fr) * 2003-09-15 2005-03-31 The Boeing Company Systeme et procede de detection a distance de formation d'arcs dans un systeme d'alimentation
US6943558B2 (en) 2003-09-15 2005-09-13 The Boeing Company System and method for remotely detecting electric arc events in a power system
US9557365B2 (en) 2013-03-14 2017-01-31 Hubbell Incorporated Apparatuses, systems and methods for detecting corona
US9897643B2 (en) 2013-03-14 2018-02-20 Hubbell Incorporated Apparatuses, systems and methods for detecting corona
CN110568329A (zh) * 2019-09-16 2019-12-13 珠海格力电器股份有限公司 电弧检测方法、家用电器及计算机可读存储介质
CN112363021A (zh) * 2020-11-13 2021-02-12 重庆大学 一种分布式线路故障检测与定位系统及方法

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AU9103198A (en) 1999-03-08
EP1053479A4 (fr) 2003-07-02
EP1004031A1 (fr) 2000-05-31
AU763046B2 (en) 2003-07-10
EP1053479A1 (fr) 2000-11-22
CA2298789C (fr) 2004-06-22
AU4072197A (en) 1999-03-08
JP2001518603A (ja) 2001-10-16
EP1004031A4 (fr) 2004-10-27
CA2298789A1 (fr) 1999-02-25
WO1999009424A1 (fr) 1999-02-25

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