EP0796434A1 - Dispositif pour la localisation de defauts sur les liaisons sous-marines de telecommunications - Google Patents
Dispositif pour la localisation de defauts sur les liaisons sous-marines de telecommunicationsInfo
- Publication number
- EP0796434A1 EP0796434A1 EP95939317A EP95939317A EP0796434A1 EP 0796434 A1 EP0796434 A1 EP 0796434A1 EP 95939317 A EP95939317 A EP 95939317A EP 95939317 A EP95939317 A EP 95939317A EP 0796434 A1 EP0796434 A1 EP 0796434A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- voltage
- fault
- current
- current characteristic
- link
- Prior art date
- Legal status (The legal status 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 status listed.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/083—Locating faults in cables, transmission lines, or networks according to type of conductors in cables, e.g. underground
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
- H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
- H04B10/079—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using measurements of the data signal
- H04B10/0791—Fault location on the transmission path
Definitions
- the invention relates to a device for locating faults on submarine telecommunications links which may for example consist of optical fiber cables or coaxial cables, by determining the resistance of a cable conductor having a fault, associated an insulation fault at sea.
- the basic element of an undersea telecommunications link is an undersea cable.
- Coaxial cable connections generally use an analog transmission mode
- fiber optic connections generally use a digital transmission mode.
- an analog submarine link that is to say implementing an analog transmission mode
- it normally comprises several sections of cables separated by repeaters which are devices active whose main function is to amplify the signal so as to compensate for the attenuation of the analog signal, linked to the propagation of the signal on the cable sections.
- regenerators When it is desired that a digital submarine link (that is to say implementing a digital transmission mode) cross a large distance, it normally comprises several sections of cables separated by regenerators or repeaters.
- the role of regenerators consists in reconstructing as faithfully as possible the digital information transmitted by a signal after it has been weakened, distorted and disturbed by its passage through a transmission cable.
- Long digital submarine links, with fiber optic cables operating at 560 Mbit / s can for example be carried out with regenerators, and faster links (typically 5 Gbit / s) are for example studied with repeaters with optical amplifier.
- Submarine connections can have a complex structure, with a trunk, and one or more branches connected to the trunk by branching units.
- the link has more than two landing points.
- composition of coaxial submarine telecommunications cables typically includes, from inside to outside: a composite conductor, consisting of a steel wire core and d '' a copper tube, an insulating polyethylene sheath, an external conductor formed of a copper or aluminum strip, an insulating polyethylene sheath. Additional layers can be added for mechanical protection of the cable.
- the composition of submarine fiber optic cables typically comprises, from inside to outside: an optical module containing optical fibers, a composite conductor surrounding the optical module, made with a steel wire vault used to guarantee the mechanical resistance of the cable to traction and with a copper tube surrounding this vault, an insulating polyethylene sheath. Additional layers can be added for mechanical protection of the cable.
- the supply of electrical energy to these active devices is usually ensured by injecting a current into a cable conductor, the various active devices being supplied in series, according to a process well known to specialists, who speak of remote power supply.
- the remote supply of the connection is generally provided by the composite conductor.
- the outgoing remote supply current flows in the composite conductor and the return current flows in sea water and possibly in the land, the remote supply devices providing the remote power supply electrical energy, being suitably earthed by an earth connection in the ground or an earth connection at sea.
- the remote supply devices are generally installed on the ground, close to link landing points.
- the external conductor is normally earthed at the ends of the link, and the remote power supply is carried out in a similar way to the fiber optic cable, the return current being subdivided however between sea water and land on the one hand, and the external conductor on the other.
- the impedance of a cable varying according to the frequency one can establish a law of dependence between the distance of a fault and the variation of the impedance of a section of cable according to the frequency.
- a device comprising an oscillator is present inside each repeater, and makes it possible to conduct the measurement on the faulty section.
- the audiofrequency alternating current measurement method a 25 Hz signal is sent on the electrical path and a ship searches for the sound signal produced, using an acoustic sensor; the fault is located by the modification of the acoustic signal.
- Echometry methods including the generation of an electrical signal and the analysis of the propagation time of the reflected signal.
- the localization is done by measuring the propagation time of the supposed signal reflected at the level of the fault; this method is used for submarine coaxial cables and is limited to faults appearing before the first repeater, and other special cases.
- the reflectometry methods including the generation of an optical signal, and the analysis of the propagation time of the reflected signal. Localization is done by measuring the propagation time of the supposed signal reflected at the level of the fault. This method is used for fiber optic cables, and is mainly limited to faults appearing before the first regenerator or repeater, and other special cases.
- the measurements are complex to interpret manually due to the non-linearities of the repeaters or regenerators on the links comprising them, and the processing of the measurement data necessarily calls in this case for the management and the use of a set of data on the current-voltage characteristic of each of them;
- the fault location is carried out using data on the linear resistance of the cable sections, which requires the management and manual operation of a set of data on the linear resistance of the cable sections.
- the subject of the invention is a device for locating faults in submarine links by measuring the resistance in direct current, making it possible to overcome these limitations.
- a device for locating faults on submarine telecommunications links is provided with two terminals, one intended to be connected to one of the conductors of the submarine link, the other intended to be launched or landed, and is characterized in that firstly it can automatically supply an electrical power of at least 100 watts to the submarine connection in the form of regulated direct current, when the voltage-current characteristic of the latter allows it, secondly in that it can absorb an electrical power of at least 1 Watt of the submarine connection when the voltage-current characteristic of the latter allows it, thirdly in that it has one or more databases on the linear resistances of cable sections, or one or more databases on the voltage-current characteristics of repeaters or regenerators, fourthly that it can automatically provide, alone or in conjunction with another device according to the invention, measurements allowing the determination of part of the voltage-current characteristic of the end of the submarine link to which the device is connected , fifthly in that it is capable of automatically processing this part of voltage-current characteristic by exploiting data from one or more databases, to estimate the location of the fault, by a treatment capable
- the device according to the invention can therefore supply direct current to the link in order to take a reading of part of the voltage-current characteristic.
- the device according to the invention can therefore for example be connected to the cable in the same way as one connects a remote power supply. Given the noise voltage which can reach a few volts peak-to-peak at the end of a long link, it may be desired to provide a large current to the submarine link so as to obtain a useful voltage with the best ratio signal to noise possible.
- the resistance of the cable sections of a fiber optic link of 1570 km could have a value of 0.97 ⁇ / km
- the 12 regenerators could have a resistance of 4314 ⁇ at 10 mA, 1268 ⁇ at 100 mA, and 268 ⁇ at 1.6 A which is the nominal operating current.
- Supplying the link with 1.6 A during the measurement will reduce the relative contribution of noise to the measured signal, but in the case of this example, will require a voltage of 2865 Volts, therefore 4584 Watts.
- Current regulation makes it possible to control the current in the cable, despite fluctuating noise voltages. It will be noted that it will generally be advantageous for a device according to the invention to be capable of automatically changing the polarity of the current which it supplies, this advantage appearing clearly in the description which follows.
- the device according to the invention can absorb the electrical power that the submarine link would provide, so that it can in all circumstances discharge the capacity constituted by the cable, of the order of 0.18 ⁇ F / km, or so as to be able to discharge the battery appearing due to the fault, when the latter comprises contact between a metallic conductor of the cable and seawater.
- the discharge of this electrochemical cell prior to certain measurements, makes it possible to '' increase the precision, according to a technique well known to specialists.
- the determination of part of the voltage-current characteristic of the end of the link to which the device is connected can be done by imposing one or more current setpoints over time, and by measuring over time one or more corresponding voltages.
- the methods allowing to take into account the linear resistances of the cable sections and the voltage-current characteristics of the regenerators or repeaters, from the exploitation of data on the cables or on the repeaters or regenerators are well known to specialists and their IT implementation using databases, so as to obtain automatic processing, can be done by methods known to computer specialists.
- the databases used in a device according to the invention could for example be designed in such a way that they allow the easy introduction of the parameters of a link, and their subsequent modifications, in order to be able to manage the developments occurring on a link, for example following repairs.
- type 2 fault a sectioning of the cable without breaking the galvanic isolation between seawater and a normally insulated cable conductor. This type of defect will be encountered, for example, if the rupture occurs on a cable stretched in such a way that the polyethylene covers the conductive parts in a leaktight manner.
- type 3 fault a break in the insulation of a conductor of the normally insulated cable, without this conductor being cut. Defects may differ from those of the above types, but type 1, 2 and 3 defects cover a large proportion of the cases encountered in practice.
- a device according to the invention could be designed so as to be able to automatically apply this type of procedure.
- Measurements allowing the determination of part of the voltage-current characteristic of the end of the link submarine to which the device is connected are affected by different causes of electrical noise, among which the difference in telluric potential, well known to specialists, generally plays a preponderant role. This potential difference has a continuous component, but it is also likely to change quickly.
- a device can for example implement a localization of the fault by a treatment capable of not being distorted by the voltage-current characteristic of the fault, based on a fault model according to which the voltage-current characteristic of the fault is modeled in a limited range of current values by a voltage whose absolute value of the difference with the electromotive force of the fault is equal to the absolute value of the current raised to a negative power greater than minus one.
- a treatment capable of not being distorted by the voltage-current characteristic of the fault, based on a fault model according to which the voltage-current characteristic of the fault is modeled in a limited range of current values by a voltage whose absolute value of the difference with the electromotive force of the fault is equal to the absolute value of the current raised to a negative power greater than minus one.
- Schaefer's method applies to type 1 and type 3 faults, a single device according to the invention being used for measurements at one end A of the link.
- the method applies when the part of the submarine link on which the measurement is made is not galvanically connected to a source of electrical energy other than the device according to the invention .
- T A is the current measured by the device according to the invention
- R A the resistance of the cable sections from the end A to the fault
- V RA H A the voltage resulting from the voltage-current characteristic of all the repeat
- this value of R A can according to (4) for example be deduced from the ordinate at the origin of an affine function obtained by linear regression on values of variables deducted from measurement data.
- V R ⁇ CT affine function obtained by linear regression on values of variables deducted from measurement data.
- the part of the voltage-current characteristic of the end of the link to which the device is connected may be limited to three measurement points , including one with zero current.
- the location will gain in precision if more measurement points are used in the data processing algorithm, which may only take into account the measurement points for which the behavior described by (4) is verified, which will lead it normally to reject points corresponding to an excessive or too low current surface density on the fault, the field of validity of (1) being limited.
- a device according to the invention can for example implement a treatment capable of not being distorted by the voltage-current characteristic of the fault, based on the exploitation of measurements provided jointly with a second device according to the invention, such so that the current flowing in the fault is negligible in steady state during the measurements used for localization. This is what we call the conjugate method.
- the combined method is applicable to type 3 faults.
- Two ends A and B of the submarine link must be used, at each of which is connected a device according to the invention, the part of the submarine link on which the measurement is carried out which must not be galvanically connected to a source of electrical energy other than the two devices according to the invention.
- Both devices according to the invention simultaneously apply a current of the same direction and practically the same value at the two ends of the link.
- the conservation of the current therefore requires that in steady state the current in the fault is practically zero, and therefore that its potential with respect to the land or the sea is practically zero.
- the part of the voltage-current characteristic of the end of the link to which the device is connected may be limited to two measurement points, one of which at zero current.
- a device comprises a modem, in order to allow the realization of automatic measurements jointly with another device according to the invention.
- the dialogue carried out between two devices according to the invention through their respective modems allows the automation of a localization according to the combined method.
- the fault locations by the combined method are generally more precise than those made by the Schaefer method, but they obviously cannot be applied to type 1 faults.
- a device according to the invention can for example implement a localization of the fault by a treatment capable of not being distorted by the voltage-current characteristic of the fault, relying on a modeling of the fault arising from theoretical results of 1 ' electrochemistry.
- a localization method “physical method”.
- a physical method may differ from Schaefer's method only in its assumptions and its data processing algorithms. It is worth noting that the method of
- V A0 and I A0 are a particular couple of values of V A and I A , the two couples having to be taken in the field of validity of (7).
- V A and J A we can write a second equation similar to (8), with which it is easy to eliminate the constant K, and, if we know the value V M ⁇ I A ), to derive the value of R A , which allows the location of the fault to be deduced from the data on the linear resistance of the cable sections.
- the part of the voltage-current characteristic of the end of the link to which the device is connected may be limited to three measurement points , or to another minimum number of measurement points depending on the variant chosen.
- the location will gain in precision if more measurement points are used in the data processing algorithm, which may only take into account the measurement points for which the behavior described by the postulated theoretical expression is verified, which it will normally lead it to reject points corresponding to an excessive or too low current surface density on the fault, the field of validity of the usable theoretical expressions being generally limited.
- a device according to the invention can be produced in such a way that it can take into account the supposed temperature of the sea surrounding the connection, to correct the linear resistance of the cable sections or the voltage-current characteristic of the regenerators as a function of this.
- assumed temperature may depend on the abscissa along the bond. This temperature may also depend on the time of year, or the time of the measurement.
- the voltages measured by a device according to the invention result not only from the value of the injected current, and from the characteristics of the link and of the fault, but also of a noise voltage which can be caused by phenomena of natural origin or artificial phenomena.
- a device according to the invention could therefore be provided with analog or digital filters making it possible to filter a certain part of the noise affecting the measurements.
- analog low pass filter with a cutoff frequency of 2 Hz
- digital low pass filtering with a cutoff frequency that can be adapted according to the level noise and response time desired, achievable by methods well known to those skilled in the art, and providing appropriate averaging of a plurality of sampled measurements.
- a device may include a circuit breaker capable of interrupting the current if the value thereof exceeds the admissible values by the submarine link.
- the values of the disjunction threshold may be different for the negative currents and the positive currents.
- the connections comprising regenerators or repeaters are in fact liable to be damaged by an excessive current.
- an optical fiber submarine link can be specified with a maximum current in the forward direction of 1700 mA, and a maximum current in the reverse direction of 200 mA, while its nominal operating current (in the direct direction) will be 1600 mA. Excessive currents exceeding the admissible value of the connection can for example be produced in the event of failure of the current regulation of the device according to the invention.
- a device according to the invention could be constituted in such a way that it makes it possible, in all circumstances, to guarantee the safety of people with regard to overvoltages which may occur on the submarine link.
- overvoltages are in particular possible when a fault location operation is carried out on a branch of the link normally disconnected from the rest of the link, and an untimely switchover of a branch unit occurs, which can lead to overvoltages. of the order of 10 kV.
- Electronics specialists know techniques making it possible to ensure the safety of people in the event of such overvoltages, one of these techniques being able to comprise the galvanic separation by one or more optical fibers between different parts of the device according to the invention:
- a device according to the invention can naturally locate a defect by its curvilinear abscissa, along the submarine connection, since the localization exploits the linear resistance of the sections of the connection.
- a device according to the invention could also include a database on the geographic position of the link, and deduce from this information the geographic position of the fault, for example by delivering its latitude and longitude.
- a device according to the invention can also be designed so that it also allows the location of faults comprising the rupture of a conductor, this conductor remaining isolated from the sea, by determining the capacity of this conductor at sea, and by using a database on the linear capacity of cable sections. It is therefore a question of the location of what we have called a type 2 fault.
- the determination of the capacity between the conductor and the sea can for example be carried out by the device according to the invention, by injecting a current into this conductor previously discharged, and by processing the evolution of the voltages measured on this conductor over time.
- a device according to the invention comprises a supply and measurement drawer (3) capable of delivering up to 1.6 A at 3.1 kV, and carrying out voltage and current measurements with an accuracy better than 10 " 4 , an intermediate box (4), a computer link according to standard IEC 625 (7), a control computer (5) capable of controlling an IEC 625 bus, an optical link with two optical fibers (6), and a modem
- the intermediate unit (4) has the particular function of transforming the dialogue of the computer link (7), where the information flow in the form of electrical signals, in a dialogue on the optical link where the information flows in the form of optical signals, according to any one of the methods well known to specialists.
- the presence of an optical link longer than one meter allows perfect galvanic isolation between the power and measurement drawer (3) and the control computer (5), and therefore guarantees operator safety in incident on the submarine link measured.
- the role of the control computer (5) is to ensure the automation of the location, and the dialogue with the operator.
- the device according to the invention (9) injects a direct current into the cable conductor (1) on which there is a type 1 fault, so that all of the injected current crosses the fault (2) and returns via the Earth.
- the processing of measurements according to this mode of use can be done according to the Schaefer method or according to a physical method.
- the modem (8) is not used in this particular mode of use.
- FIG. 2 represents a second particular mode of use of a device according to the invention, given by way of nonlimiting example.
- the marks (1) and (2) designate as before the submarine link and its defect, which is here a type 3 defect, and the marks (3) to (8) designate the same functional blocks as previously, d ' a first device according to the invention (9).
- a telephone link (10) connects the first device according to the invention (9) and a second device according to the invention (11), identical to the previous one, the link being effected by means of the modem, each of the devices (9) and (11) are provided.
- the current in the fault is therefore zero.
- the voltages relative to earth supplied by the power and measurement drawers of the devices (9) and (11), are of opposite signs, and each of them is characteristic of the voltage-current characteristic of the part of the connection between the measurement point considered and the fault.
- the link telephone (10) allows the control computer of each of the devices (9) and (11) to execute instructions and measurements synchronized with the power and measurement drawers, and to perform a location using the combined method automatically .
- FIG. 3 represents a third particular mode of use of a device according to the invention, given by way of nonlimiting example.
- the marks (1) and (2) designate as before the submarine link and its defect, which is here a type 2 defect, and the marks (3) to (8) designate the same functional blocks as before, of a device according to the invention (9).
- the link behaves like a capacity.
- the power and measurement slide provides a constant current, for example of 10 mA, and operates an acquisition of the voltage applied to the submarine link every 100 ms. The evolution of this voltage over time is characteristic of the capacity of the link, from the measurement point to the fault.
- a device according to the invention allows automatic, precise and rapid location of faults occurring on the submarine links.
- a device according to the invention can be particularly applied to the location of faults on submarine links produced with fiber optic cables or with coaxial cables.
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- General Physics & Mathematics (AREA)
- Locating Faults (AREA)
- Monitoring And Testing Of Transmission In General (AREA)
- Measurement Of Resistance Or Impedance (AREA)
Abstract
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR9414689 | 1994-12-05 | ||
FR9414689A FR2727762A1 (fr) | 1994-12-05 | 1994-12-05 | Dispositif pour la localisation de defauts sur les liaisons sous-marines de telecommunications |
PCT/FR1995/001445 WO1996018111A1 (fr) | 1994-12-05 | 1995-11-03 | Dispositif pour la localisation de defauts sur les liaisons sous-marines de telecommunications |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0796434A1 true EP0796434A1 (fr) | 1997-09-24 |
Family
ID=9469548
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP95939317A Withdrawn EP0796434A1 (fr) | 1994-12-05 | 1995-11-03 | Dispositif pour la localisation de defauts sur les liaisons sous-marines de telecommunications |
Country Status (5)
Country | Link |
---|---|
US (1) | US5883517A (fr) |
EP (1) | EP0796434A1 (fr) |
AU (1) | AU4119296A (fr) |
FR (1) | FR2727762A1 (fr) |
WO (1) | WO1996018111A1 (fr) |
Families Citing this family (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU2002319784A1 (en) * | 2001-08-10 | 2003-02-24 | Adaptive Networks, Inc. | Digital equalization process and mechanism |
KR100496994B1 (ko) * | 2003-04-04 | 2005-06-23 | 엘에스전선 주식회사 | 지중 전력케이블의 실시간 평가장치 및 그 방법 |
DE202005009098U1 (de) * | 2005-06-09 | 2005-09-22 | Casier Gmbh | Leuchtanordnung zur flächenhaften Lichtabstrahlung |
US8953944B2 (en) * | 2011-01-05 | 2015-02-10 | Woods Hole Oceanographic Institution | Systems and methods for establishing an underwater optical communication network |
US7823643B2 (en) | 2006-06-05 | 2010-11-02 | Fmc Technologies Inc. | Insulation shroud with internal support structure |
US7382947B1 (en) * | 2006-08-29 | 2008-06-03 | Laurence Moskowitz | Remote monitoring of undersea cable systems |
GB2457888C (en) * | 2008-02-26 | 2013-08-21 | Zetechtics Ltd | Subsea test apparatus, assembly and method |
US20110031977A1 (en) * | 2008-04-16 | 2011-02-10 | O'sullivan Charles Brendan | System and method for locating line faults in a medium voltage network |
GB2463487A (en) * | 2008-09-15 | 2010-03-17 | Viper Subsea Ltd | Subsea protection device |
GB0921632D0 (en) | 2009-12-10 | 2010-01-27 | Viper Subsea Ltd | Line monitoring device |
GB201212868D0 (en) | 2012-07-20 | 2012-09-05 | Viper Subsea Technology Ltd | Subsea deployed line insulation monitor |
US9170389B2 (en) * | 2012-08-28 | 2015-10-27 | Corning Cable Systems Llc | Hybrid fiber optic cable systems |
US10199810B2 (en) * | 2013-02-20 | 2019-02-05 | Viper Innovations Ltd | Rejuvenation of subsea electrical cable insulation |
EP3073049A1 (fr) * | 2015-03-26 | 2016-09-28 | Siemens Aktiengesellschaft | Procédé pour déterminer un état de fonctionnement d'une unité de connecteur sous-marin |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2592492B1 (fr) * | 1985-12-30 | 1988-04-01 | Enertec | Procede de localisation d'un defaut sur une ligne electrique |
CH666968A5 (fr) * | 1986-03-25 | 1988-08-31 | Gerard Andre Lavanchy | Procede et dispositif pour la localisation d'un defaut dans un cable electrique. |
US4929900A (en) * | 1987-12-29 | 1990-05-29 | Industrial Technology, Inc. | Method for locating conductive faults in telephone and similar cables |
FI84302C (fi) * | 1989-04-25 | 1991-11-11 | Tipteck Oy | Foerfarande och anordning foer lokalisering av en i jord eller vatten nedsaenkt kabels laege eller kabelfel fraon marken eller ovan vatten. |
GB2242324B (en) * | 1990-03-22 | 1993-09-22 | Stc Plc | Fault location. |
-
1994
- 1994-12-05 FR FR9414689A patent/FR2727762A1/fr active Granted
-
1995
- 1995-11-03 WO PCT/FR1995/001445 patent/WO1996018111A1/fr not_active Application Discontinuation
- 1995-11-03 AU AU41192/96A patent/AU4119296A/en not_active Abandoned
- 1995-11-03 EP EP95939317A patent/EP0796434A1/fr not_active Withdrawn
- 1995-11-03 US US08/849,505 patent/US5883517A/en not_active Expired - Fee Related
Non-Patent Citations (1)
Title |
---|
See references of WO9618111A1 * |
Also Published As
Publication number | Publication date |
---|---|
WO1996018111A1 (fr) | 1996-06-13 |
FR2727762B1 (fr) | 1997-02-21 |
FR2727762A1 (fr) | 1996-06-07 |
AU4119296A (en) | 1996-06-26 |
US5883517A (en) | 1999-03-16 |
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