EP1145019A2 - Device and method for optically detecting an electric current and a component of an electric field - Google Patents

Device and method for optically detecting an electric current and a component of an electric field

Info

Publication number
EP1145019A2
EP1145019A2 EP99944241A EP99944241A EP1145019A2 EP 1145019 A2 EP1145019 A2 EP 1145019A2 EP 99944241 A EP99944241 A EP 99944241A EP 99944241 A EP99944241 A EP 99944241A EP 1145019 A2 EP1145019 A2 EP 1145019A2
Authority
EP
European Patent Office
Prior art keywords
component
light signal
current
bragg
optical
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Withdrawn
Application number
EP99944241A
Other languages
German (de)
French (fr)
Other versions
EP1145019A3 (en
Inventor
Uwe Linnert
Siegfried Birkle
Thomas Bosselmann
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens AG
Original Assignee
Siemens AG
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 Siemens AG filed Critical Siemens AG
Publication of EP1145019A2 publication Critical patent/EP1145019A2/en
Publication of EP1145019A3 publication Critical patent/EP1145019A3/en
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
    • G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
    • G01R15/24—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using light-modulating devices

Definitions

  • the invention relates to a device and a method for optically detecting an electrical current and at least one component of an electrical field.
  • EP 088 419 B1 discloses an optical measuring device for measuring an electrical current flowing in a current conductor using the Faraday effect.
  • Such an optical measuring device is also referred to as a magneto-optical current transformer.
  • the Faraday effect is the rotation of the plane of polarization of linearly polarized light, which spreads in a medium in the presence of a magnetic field. The angle of this rotation is proportional to the path integral over the magnetic field along the path covered by the light with the Verdet constant as the proportionality constant.
  • a Faraday element is arranged in the vicinity of the current conductor and contains an optically transparent material that shows the Faraday effect.
  • this Faraday element is designed as a solid glass ring which surrounds the current conductor. Linearly polarized light is coupled into this.
  • the magnetic field generated by the electrical current causes the plane of polarization of the light propagating in the solid glass ring to rotate about a polarization rotation which is evaluated by an evaluation unit as a measure of the strength of the magnetic field and thus of the strength of the electrical current.
  • the light which carries measurement information about the electrical current m of a polarization modulation, m an analyzer, which is designed as a beam-splitting Wollaston prism, m two partial light signals with polarity oriented perpendicular to each other. station levels divided.
  • the analyzer converts the polarization modulation into an intensity modulation of the two partial light signals.
  • the measurement information is thus encoded in the intensity of the two partial light signals.
  • the Faraday element is designed as an optical monomode fiber which surrounds the current conductor in the form of a measuring winding with N turns.
  • the light guided in the monomode phase circulates the current conductor ⁇ aher a total of N times. With each revolution, the light undergoes a rotation of its polarization state in accordance with the strength of the electrical current or the magnetic field.
  • the measuring sensitivity of this fiber-optic Faraday element can thus be set by the number of turns.
  • EP 0 613 015 AI discloses an optical measuring device for measuring an electrical voltage using the Pockels effect, which is also referred to as an electro-optical voltage converter.
  • the electrical voltage to be measured is applied to an electro-optical crystal, which then modifies a light signal that is transmitted through it with its polarization properties. This modification is traced back in an evaluation unit to the causal measurement variable, the electrical voltage.
  • the electro-optical crystal causes the change in the polarization properties due to an electric field forming in the crystal as a result of the applied electrical voltage.
  • an optical combination converter for an electrical current and an electrical voltage.
  • This includes a magneto-optical current converter with a solid glass ring and a electro-optical voltage converter with an electro-optical crystal, which is connected to a capacitive voltage divider, m den Combined converter integrated.
  • the electro-optical voltage transformer detects in particular the electric field strength that prevails within a partial capacitance of the capacitive voltage divider, in which the electro-optical crystal is arranged.
  • the electro-optical voltage converter and the magneto-optical current converter have completely independent light paths.
  • the integration with the combination converter is carried out in such a way that the two single converters, which are not optically connected to one another, are only accommodated in a common housing in the form of a high-voltage insulator.
  • the measurement information is transmitted in the form of an intensity modulation of the light signal carried in an optical waveguide. Problems can arise here, since the light intensity in the optical waveguide is due to external disturbance flows such as mechanical vibrations or temperature fluctuations react sensitively.
  • An optical sensor based on a fiber Bragg grating is known from the review article "In-fiber Bragg graph sensors" by YJ Rao, Meas. Sei. Technol., Vol. 8, 1991, pages 355 to 375 A length change in an optical fiber can be detected with the aid of a fiber Bragg grating.
  • a Bragg grating which is initially introduced into an optical fiber is essentially a periodic local modulation of the refractive index in the core of the optical fiber. This modulation of the refractive index in Kern is also referred to below as “core index modulation *.
  • the locally limited core index modulation represents a discontinuity for an incident light signal, at which partial or total reflections occur at certain wavelengths. Which wavelength or which wavelength portion is affected depends on the formation of the
  • Core index modulation of the Bragg grating By forming the core index modulation, the Bragg grating is consequently tuned to a certain wavelength or a certain wavelength spectrum.
  • the wavelength content of both the reflected and the transmitted i.e. of the transmitted light signal.
  • the corresponding modification in the wavelength content can thus be used as a measure of the change in length of the optical fiber.
  • Elongation / compression also detect other physical parameters such as temperature, pressure, sound, acceleration, high magnetic fields and force.
  • An embodiment of the sensor based on the fiber Bragg grating for the detection of an electrical field or an electrical voltage cannot be found in the above-mentioned review article.
  • the object of the invention is to provide a device and a method of the type described in the introduction, which enable simultaneous detection of electrical current and a component of an electrical field to be improved or simplified compared to the prior art. In particular, optical components should be saved.
  • the device according to the invention for optically detecting an electrical current and at least one component of an electric field is a device which has a light path with an optical series connection of - at least one current-sensitive Faraday element and - at least one on the at least one component of the electrical Field sensitive element includes.
  • a method is specified according to the features of independent claim 13.
  • a method of optically detecting an electric current and at least one component of an electric field there is a method in which a) e transmission light signal is generated and m an optical rows ⁇ circuit of at least one strome pfmdlichen Faraday element and at least one the at least one component of the electric field sensitive element is fed, at least em portion of the transmitted light signal in a successive sequence b) by the at least one current sensitive Faraday element having a polarization state and c) by the at least one to the at least one component of the electric field -sensitive element in a direction different from the polarization state opti ⁇ 's property is influenced, and d) from influencing the polarization state different from the property of at least a first measured quantity for the at least one component of the electric field, and e) from the Bee Influence of the polarization state, a second measurand for the electrical current is derived.
  • the invention is based on the knowledge that the optical detection of an electric current and a component of an electric field can be combined in an advantageous manner by em a single light signal both by at least one current sensitive Faraday element and by at least one em to the at least one a component of Electrical field sensitive element runs through and is influenced by the respective size to be measured.
  • the component of the electric field is also referred to below as “field component w .
  • the Faraday element and the component on the at least one Feldkom ⁇ sensitive element are in optical series circuit, the sequence in this context ⁇ hang does not matter.
  • the Faraday element and the element sensitive to the field component influence various and, above all, selectively detectable parameters of the transmitted light signal. These selectively detectable parameters can be, for example, the polarization state and the wavelength content of the transmitted light signal.
  • the electrical current and the field component smd can thus also be detected separately, ie individually, with the combined arrangement of the Faraday element and the element sensitive to the field component in the optical series connection.
  • Operation of the Faraday element and the element sensitive to the field component are optical components in the solution according to the invention, e.g. a second light source or separate supply or discharge optical fibers e - saved.
  • the device according to the invention for detecting electrical current and a field component can thus be manufactured more cheaply and also has a smaller space requirement than two separate devices.
  • the device is therefore particularly well suited for use in electrical energy supply. Because of its small size, the device can be merged particularly easily with other existing equipment, such as an outdoor circuit breaker or a gas-insulated switchgear. Special refinements and developments of the device and the method according to the invention result from the respective dependent subclaims.
  • An embodiment variant is advantageous in which the at least one element sensitive to the at least one field component is designed as a Bragg element. Because of the coding of the measurement information in the wavelength content that is generally customary with Bragg elements, this embodiment variant has a significantly reduced sensitivity to disturbance variables compared to the prior art. The relevant disturbance variables influence the intensity of a light signal used to transmit the measurement information more than the wavelength content.
  • the Bragg element contains a piezo body, which due to its piezoelectricity reacts with a change in shape to the at least one field component.
  • An optical fiber is mechanically connected to the piezo body in such a way that the change in shape of the piezo body causes a change in length of the optical fiber.
  • the optical waveguide can be both an infeed and an outfeed optical waveguide of the Faraday element. The order of the arrangement of the Faraday element and the Bragg element does not matter.
  • Within the optical waveguide there is a Bragg grating with a predetermined Bragg wavelength exactly at the point which is changed by the change in shape of the piezo body m the length.
  • the local change in the length of the optical waveguide also changes the Kernmdex modulation on which the Bragg grating is based, so that a different wavelength component is reflected by a transmitted light signal which strikes the Bragg grating than in the absence of the field component.
  • both the portion of the transmitted light signal which passes through the Bragg element which is referred to here as the transmitted light signal
  • that at the Bragg element reflected portion of the transmitted light signal which is referred to here as a reflected light signal
  • the reflected light signal essentially consists of a wavelength that corresponds to the Bragg wavelength.
  • the transmitted light signal has a gap in its wavelength spectrum precisely at the location of the Bragg wavelength.
  • the piezo body consists of single crystals such as quartz, lithium niobate
  • a piezoelectric polymer such as polyvinylidene fluoride (PVDF) or a piezoceramic. Since the piezoelectric single crystals that can be used all have anisotropic behavior, the piezo body can be cut out of the relevant crystal with different orientations.
  • PVDF polyvinylidene fluoride
  • the light path which contains the optical series connection of the Faraday element and the element sensitive to the field component, comprises a plurality of optical fibers.
  • these optical waveguides can have a different type of optical waveguide.
  • Optical waveguides in the form of a multimode fiber, a single-mode fiber, a polarizing fiber or else a polarization-maintaining fiber are preferably used.
  • Bragg elements with Bragg gratings are integrated in the incoming and outgoing optical waveguides of the Faraday element.
  • the individual Bragg elements react to different field components that are present along the incoming and outgoing optical waveguide.
  • a broadband light source is provided, the emitted light spectrum of which introduces at least all Bragg wavelengths of the optical fibers leading to and from the fiber.
  • Suitable broadband light sources in this regard are an SLD (superluminescent diode), an ELED (edge-emitting light-emitting g diode), an SFS (superfluorescent fiber source) or an TFL (tunable fiber laser).
  • the emitted wavelength spectrum of these light sources then preferably has a half width of up to 200 nm.
  • Light sources with an even larger emission spectrum smd are also suitable.
  • the emission spectrum here means the wavelength range that the TFL sweeps over. More than one light source can also be provided, which feed light into the light path at a time and / or spectrally offset from one another.
  • An embodiment is advantageous which carries out a wavelength-selective evaluation of at least the portion of the transmitted light signal which is influenced by the Faraday element in its polarization state and by at least one Bragg element in its wavelength content.
  • the measurement information about the field component present at the respective Bragg element and about the electrical current flowing through the Faraday element can be determined by a wavelength-selective division via an optical filter or a spectrometer in accordance with the respective Bragg wavelengths.
  • a variant of the method is particularly advantageous in which, in addition to the at least one first measurement variable for the at least one field component and the second measurement variable for the electrical current, a third measurement variable for an electrical voltage of a current conductor in which the electrical current flows is also determined.
  • This third measurand is derived from the first measurands for the field components. Since field components are measured along the incoming or outgoing optical waveguide, the electrical voltage defined as the integral of the electrical field profile between the current conductor and a point at earth potential, for example the location of the evaluation unit, can be approximated by these measured field components. For this purpose, the line integral is replaced by a summation of the first measured quantities for the field components, weighted with the dimensions of the respective piezo bodies. The method thus provides a measurement variable for the electrical current and for the electrical voltage.
  • Figures 1 and 2 devices for optical detection of an electric current via a fiber coil and of field components via Bragg elements
  • Figure 3 shows another device for optical detection of an electric current via a solid glass ring and a field component via a Bragg element
  • Figure 4 em Bragg -Element for the optical detection of a field component.
  • FIG. 1 shows a device for optically detecting an electrical current I and components E (with 1 ⁇ 1 ⁇ n) of an electrical field, which are also referred to here as field components E x .
  • the running index “l *” takes values from 1 to n from the set of natural numbers.
  • the substantially sensitive components of the device smd em stromempfmd liehes Faraday element F in the form of a fiber coil and a plurality of Bragg elements B 1 (1 ⁇ l ⁇ n), the LT respectively on the field component E, the respective at Bragg element B is present, , react sensitively.
  • the electrical current I flows in a current conductor 50, at which an electrical voltage U is present in relation to earth potential.
  • the Bragg elements B and the Faraday element F are connected optically to the embodiment of FIG. In this series connection, the transmitted light signal LS passes first through the Bragg elements B L and then through the Faraday element F. In the Bragg elements B x, the transmitted light signal LS undergoes a change in a wavelength content and m in the Faraday element F a change in one Polarization state.
  • the transmitted light signal LS is generated by a broadband light source 20, which is designed as a superluminescent diode (SLD), and is fed via a coupler 40 m to a supplying optical waveguide 11 of the Faraday element F.
  • this feeding optical waveguide 11 is designed as a single-mode fiber.
  • the Bragg elements B x smd are integrated in this supplying optical waveguide 11.
  • the Bragg elements B x are matched to different Bragg wavelengths ⁇ x (with 1 ⁇ 1 ⁇ n) by introducing different Kernmdex modulations in each case into the supplying optical waveguide 11. This is done by different local modulation periods.
  • the transmitted light signal LS is then at least partially reflected in the spectral range of the respective wavelength ⁇ x at the associated Bragg element B x .
  • By reflecting the broadcast Light signal LS at the individual Kernmdex modulations of the respective Bragg elements B x runs back a reflected light signal LR with a wavelength content, which comprises the individual Bragg wavelengths ⁇ ", in the direction of the broadband light source 20.
  • the reflected light signal LR is redirected in the direction of an evaluation unit 30.
  • an emitted light signal LT which is composed of wavelength components of the transmitted light signal LS, which are generated by the Bragg Wavelengths ⁇ x different smd. These wavelength components pass through all Bragg elements B x unhindered.
  • the transmitted light signal LT thus has a wavelength spectrum provided with gaps, the gaps being located precisely at the locations of the individual Bragg wavelengths ⁇ .
  • the wavelength content of both the reflected and the transmitted light signals LR and LT is influenced.
  • the reflected light signal LR With the reflected light signal LR, the individual Bragg wavelengths ⁇ _ shift themselves, with the transmitted light signal LT, however, said gaps in the wavelength spectrum.
  • the transmitted light signal LT is also fed to the evaluation unit 30 in the further course, the detection of both displacements m of the evaluation unit 30 enables a redundant determination of first measured quantities Ml x for the field components E x .
  • the respective field component E x is inferred from the respective displacements.
  • the transmitted light signal LT Before the transmitted light signal LT reaches the evaluation unit 30, it first passes through the Faraday element F. Vor Entry into the Faraday element F becomes the transmitted one.
  • Light signal LT m linearly polarized a polarizing optical waveguide 12.
  • the linear polarization state is then rotated about a Faraday rotation under the influence of the electrical current I flowing in the current conductor 50.
  • the resulting Faraday rotation is dependent on the material of the fiber spool, the number of turns and the electrical current I.
  • This current-coded transmitted light signal LT ' contains, in its wavelength content, coded measurement information about the field components E x and in its polarization state, coded measurement information about the electrical current I.
  • the current-coded transmitted light signal LT' is transmitted via a discharging optical waveguide 13 of the Faraday element F of the evaluation unit 30 fed.
  • the discharging optical waveguide 13 is designed in the device of FIG. 1 as a polarization-maintaining optical waveguide.
  • the evaluation unit 30 initially contains means for wavelength-selective division of both the reflected light signal LR and the current-coded transmitted light signal LT 'at the input.
  • the division is made into frequency ranges, each of which comprises only a single Bragg wavelength ⁇ ⁇ .
  • the first measured quantities M1 L for the field components E x can be determined from these wavelength ranges.
  • em another wavelength component is provided which ⁇ none of the Bragg wavelengths. includes.
  • This wavelength range is used to determine a second measurement variable M2 for the electrical current I.
  • the evaluation unit has a known arrangement for evaluating a light signal which contains the measurement information about the electrical current I in the form of a coding or modulation of the polarization - condition included. This arrangement includes in particular an analyzer that converts the polarization modulation into a. Converts intensity modulation.
  • the supplying optical waveguide 11 runs along a connection path between the current conductor 50 and the broadband light source 20, which is also at ground potential like the evaluation unit 30.
  • the electrical voltage U that is present on the current conductor 50 is thus obtained pending.
  • This line integral can be approximated with the aid of the field components E. detected via the Bragg elements B.
  • the approximation is carried out by summing products from the first measured quantities Ml . for the field components E 1 and local dimensions of the associated Bragg elements B.
  • This evaluation is carried out in a voltage unit 31 which is connected downstream of the evaluation unit 30.
  • the first measured variables M1,... Serve as the input variable of the voltage unit 31 .
  • the voltage unit 31 supplies a third measurement variable M3 for the electrical voltage U. Consequently, with the device shown in FIG. 1, both the electrical current I and the electrical voltage U can be detected and evaluated.
  • the device thus represents a combination converter.
  • the broadband light source 20 together with electronic control and the evaluation unit 30 and the voltage unit 31 are combined to form a single optoelectronic unit.
  • the calculations for the third measurement variable M3 are then carried out by the same computing unit, for example in a microprocessor, in which the first measurement variables Ml x and the second measurement variable M2 are also determined.
  • the device shown in FIG. 2 is also used for optically detecting the electrical current I and the electrical voltage U. It is similar in large parts to the device shown in FIG. There is an essential difference However, the fact that the Bragg elements Bi are not integrated in the exporting ⁇ approximately example of Figure 2 in the feeding optical waveguide 11, but in the efferent optical fiber. 13
  • the transmitted light signal LS is thus first fed into the Faraday element F and its polarization state is changed by the electrical current I.
  • a current-coded transmission light signal LS ' is then present at the output of the Faraday element F. This passes through the Bragg elements Bi.
  • the current-coded transmitted light signal LT ' is present at its output, which in turn is fed into the evaluation unit 30.
  • the evaluation is carried out analogously to the exemplary embodiment in FIG. 1.
  • the exemplary embodiment from FIG. 2 does not contain a light branch which supplies a reflected light signal LR to the evaluation unit 30.
  • the light components reflected on the Bragg elements Bi pass through the polarizing optical waveguide 12 a second time on their way back in the direction of the broadband light source 20, where they experience a very strong attenuation, so that an evaluation in the evaluation unit 30 is no longer useful.
  • FIG. 3 shows a further device for optically detecting an electrical current I and a field component E-.
  • the Faraday element F is designed as a solid glass ring.
  • the transmitted light signal LT leaves the leading optical waveguide 11 and is linearly polarized in a solid polarizer 120, which corresponds to the polarizing fiber 12 of the exemplary embodiments in FIGS.
  • the linearly polarized transmitted light signal LT passes once through the massive glass ring giving the current conductor 50 u and is thereby influenced by the electrical current I in its polarization state.
  • this polarization modulation is converted to an intensity modulation by a beam-splitting analyzer 121 in the form of a Wollaston prism.
  • the analyzer 121 generates first and second current-coded partial light signals LT1 'and LT2', which each carry the measurement information about the electrical current I in the form of an intensity modulation.
  • the first and second current-coded partial light signals LT1 'and LT2' are routed to the evaluation unit 30 via a first and second discharging optical waveguide 131 and 132, respectively.
  • the supplying optical waveguide 11 and the two outgoing optical waveguides 131 and 132 are each designed as single-mode fibers. However, this is not absolutely necessary. In another embodiment, multimode fibers can also be used. Except for the shifting of the implementation of the polarization modulation m the intensity modulation directly to the Faraday element F, the evaluation unit 30 of FIG. 3 is identical to that of FIG. 1.
  • the device of FIG. 3 there is only one Bragg element Bi for detecting a single field component E-. intended. This is particularly advantageous if the distance between the current conductor 50 and the earth potential is only short.
  • An example in this regard is a gas-insulated switchgear.
  • the device of FIG. 3 can also be used if only a rough approximation for the electrical voltage U is desired. The rough approximation then takes place only via the first measured quantity Mli of the field component Ei.
  • FIG. 4 shows a Bragg element Bi used for the optical detection of a field component E x in the exemplary embodiments of FIGS. 1 to 3.
  • the Bragg element B x comprises a piezo body P x . This has a bore through which, for example, the light wave conductor 11 nm is carried out.
  • the Piezokorper P x and the. feeding optical fibers 11 smd mechanically firmly connected to each other in the area of the bore.
  • the supplying optical waveguide 11 has m Bragg grating Gi with the predetermined Bragg wavelength ⁇ i in this area.
  • the Bragg grating Gi is formed by the core index modulation described above.
  • the supplying optical waveguide 11 can, however, also be wrapped around the piezo body Pi or embedded in a groove on a surface of the piezo body P x .
  • the Bragg grating Gi is also in these embodiments, not shown, in each case in the contact area of the supplying optical waveguide 11 with the piezo body P x .
  • the field component El to be measured first causes a change in shape of the piezo body Pi and as a result of a change in length of the supplying optical waveguide 11.
  • This change in length leads to a modification of the Kernmdex modulation in the Bragg grating G x , so that the shifts in the wavelength content of the reflected light signal LR as well as of the transmitted light signal LT which have already been mentioned above result.
  • These shifts smd then proportional to the causal field component El.
  • the piezo body P x consists of quartz.

Abstract

according to the invention, in an optical series connection consisting of a current-sensitive Faraday element (F) and an element (B1, Bi, Bn) which is sensitive to a component (E1, Ei, En) of an electric field, an emitted light signal (LS) is influenced such that its state of polarization and an optical property different from said state of polarization are modified. From this a first measured quantity (M11, M1i, M1n) is derived for the component (E1, Ei, En) of the electric field and a second measured quantity (M2) is derived for the electric current (I).

Description

Beschreibungdescription
Vorrichtung und Verfahren zur optischen Erfassung eines elektrischen Stroms und einer Komponente eines elektrischen FeldsDevice and method for optically detecting an electrical current and a component of an electrical field
Die Erfindung betrifft eine Vorrichtung und ein Verfahren zur optischen Erfassung eines elektrischen Stroms und mindestens einer Komponente eines elektrischen Felds.The invention relates to a device and a method for optically detecting an electrical current and at least one component of an electrical field.
Aus der EP 088 419 Bl ist eine optische Meßeinrichtung zum Messen eines m einem Stromleiter fließenden elektrischen Stroms unter Ausnutzung des Faraday-Effekts bekannt. Eine derartige optische Meßeinrichtung wird auch als magneto- optischer Stromwandler bezeichnet. Unter dem Faraday-Effekt versteht man die Drehung der Polarisationsebene von linear polarisiertem Licht, das sich m einem Medium m Anwesenheit eines Magnetfelds ausbreitet. Der Winkel dieser Drehung ist dabei proportional zum Wegintegral über dem magnetischen Feld entlang des vom Licht zurückgelegten Wegs mit der Verdet- Konstanten als Proportionalitatskonstanten. Zum Messen des Stroms ist ein Faraday-Element in der Nahe des Stromleiters angeordnet, das ein optisch transparentes, den Faraday-Effekt zeigendes Material enthalt. Im Ausfuhrungsbeispiel der EP 088 419 Bl ist dieses Faraday-Element als massiver Glasring ausgebildet, der den Stromleiter umgibt. In diesen wird linear polarisiertes Licht eingekoppelt. Das vom elektrischen Strom erzeugte Magnetfeld bewirkt eine Drehung der Polarisationsebene des sich in dem massiven Glasring ausbreitenden Lichtes um einen Polarisationsdrehwmkel, der von einer Aus- werteemheit als Maß für die Starke des Magnetfelds und damit für die Starke des elektrischen Stroms ausgewertet wird. Nach Durchlaufen des Faraday-Elements wird das Licht, das eine Meßinformation über den elektrischen Strom m einer Polarisa- tionsmodulation tragt, m einem Analysator, der als strahl- teilendes Wollaston—Prisma ausgebildet ist, m zwei Teil- lichtsignale mit senkrecht zueinander orientierten Polari- sationsebenen aufgeteilt. Zugleich uoerfuhrt der Analysator die Polarisationsmodulation in eine Intensitatsmodulation der beiden Teillichtsignale . Die Meßinformation ist somit m der Intensität der beiden Teillichtsignale codiert.EP 088 419 B1 discloses an optical measuring device for measuring an electrical current flowing in a current conductor using the Faraday effect. Such an optical measuring device is also referred to as a magneto-optical current transformer. The Faraday effect is the rotation of the plane of polarization of linearly polarized light, which spreads in a medium in the presence of a magnetic field. The angle of this rotation is proportional to the path integral over the magnetic field along the path covered by the light with the Verdet constant as the proportionality constant. To measure the current, a Faraday element is arranged in the vicinity of the current conductor and contains an optically transparent material that shows the Faraday effect. In the exemplary embodiment of EP 088 419 B1, this Faraday element is designed as a solid glass ring which surrounds the current conductor. Linearly polarized light is coupled into this. The magnetic field generated by the electrical current causes the plane of polarization of the light propagating in the solid glass ring to rotate about a polarization rotation which is evaluated by an evaluation unit as a measure of the strength of the magnetic field and thus of the strength of the electrical current. After passing through the Faraday element, the light, which carries measurement information about the electrical current m of a polarization modulation, m an analyzer, which is designed as a beam-splitting Wollaston prism, m two partial light signals with polarity oriented perpendicular to each other. station levels divided. At the same time, the analyzer converts the polarization modulation into an intensity modulation of the two partial light signals. The measurement information is thus encoded in the intensity of the two partial light signals.
In einer anderen aus der WO 91/01501 AI bekannten Ausfuhrungsform ist das Faraday-Element als optische Monomode-Faser ausgebildet, die den Stromleiter m Form einer Meßwicklung mit N Windungen umgibt. Das m der Monomode-Phase geführte Licht umlauft den Stromleiter αaher insgesamt N-mal . Bei jedem Umlauf erfahrt das Licht eine Drehung seines Polaπ- sationszustandes entsprechend der Starke des elektrischen Stroms bzw. des Magnetfelds. Durch die Windungsanzahl kann somit die Meßempfmdlichkeit dieses faseroptischen Faraday- Elements eingestellt werden.In another embodiment known from WO 91/01501 AI, the Faraday element is designed as an optical monomode fiber which surrounds the current conductor in the form of a measuring winding with N turns. The light guided in the monomode phase circulates the current conductor αaher a total of N times. With each revolution, the light undergoes a rotation of its polarization state in accordance with the strength of the electrical current or the magnetic field. The measuring sensitivity of this fiber-optic Faraday element can thus be set by the number of turns.
Außerdem ist aus der EP 0 613 015 AI eine optische Meßeinrichtung zum Messen einer elektrischen Spannung unter Ausnutzung des Pockels-Effekts bekannt, die auch als elektro- optischer Spannungswandler bezeichnet wird. Die zu messende elektrische Spannung wird dabei an einen elektrooptischen Kristall angelegt, der dann ein Lichtsignal, das durch ihn hindurchgestrahlt wird, m seinen Polaπsationseigenschaften modifiziert. Diese Modifikation wird m einer Auswerteeinheit auf die ursachlicne Meßgroße, die elektrische Spannung, zurückgeführt. Der elektrooptische Kristall ruft dabei die Änderung der Polaπsationseigenschaften aufgrund eines sich im Kristall als Folge der angelegten elektrischen Spannung ausbildenden elektrischen Feldes hervor.In addition, EP 0 613 015 AI discloses an optical measuring device for measuring an electrical voltage using the Pockels effect, which is also referred to as an electro-optical voltage converter. The electrical voltage to be measured is applied to an electro-optical crystal, which then modifies a light signal that is transmitted through it with its polarization properties. This modification is traced back in an evaluation unit to the causal measurement variable, the electrical voltage. The electro-optical crystal causes the change in the polarization properties due to an electric field forming in the crystal as a result of the applied electrical voltage.
Aus der Firmenschrift „Opti cal Combmed Current & Vol tage H. V. Sensors " , GEC-Al sthom T&D ist außerdem ein optischer Kombi-Wandler für einen elektrischen Strom und eine elektrische Spannung bekannt. Dabei sind ein magnetooptischer Strom- wandler mit einem massiven Glasring und ein elektrooptischer Spannungswandler mit einem elektrooptischen Kristall, der an einem kapazitiven Spannungsteiler angeschlossen ist, m den Kombi-Wandler integriert. Der elektrooptische Spannungswa-nd- ler erfaßt insbesondere die elektrische Feldstarke, die innerhalb einer Teilkapazitat des kapazitiven Spannungsteilers herrscht, m der der elektrooptische Kristall angeordnet ist. Der elektrooptische Spannungswandler und der magnetooptische Stromwandler verfugen über vollkommen eigenständige Lichtwege. Die Integration zu dem Kombi-Wandler ist so ausgeführt, daß die beiden optisch nicht miteinander verbundenen Einzel-Wandler lediglich m einem gemeinsamen Gehäuse in Form eines Hochspannungsisolators untergebracht sind.From the company publication "Opti cal Combmed Current & Voltage HV Sensors", GEC-Al sthom T&D, there is also known an optical combination converter for an electrical current and an electrical voltage. This includes a magneto-optical current converter with a solid glass ring and a electro-optical voltage converter with an electro-optical crystal, which is connected to a capacitive voltage divider, m den Combined converter integrated. The electro-optical voltage transformer detects in particular the electric field strength that prevails within a partial capacitance of the capacitive voltage divider, in which the electro-optical crystal is arranged. The electro-optical voltage converter and the magneto-optical current converter have completely independent light paths. The integration with the combination converter is carried out in such a way that the two single converters, which are not optically connected to one another, are only accommodated in a common housing in the form of a high-voltage insulator.
Bei den genannten Ausfuhrungsformen der optischen Wandler wird die Meßinformation m Form einer Intensitatsmodulation des m einem Lichtwellenleiter geführten Lichtsignals uber- tragen. Hierbei können Probleme auftreten, da die Lichtmten- sitat im Lichtwellenleiter auf externe Storemflusse wie z.B. mechanische Vibrationen oder Temperaturschwankungen empfindlich reagiert.In the embodiments of the optical converters mentioned, the measurement information is transmitted in the form of an intensity modulation of the light signal carried in an optical waveguide. Problems can arise here, since the light intensity in the optical waveguide is due to external disturbance flows such as mechanical vibrations or temperature fluctuations react sensitively.
Aus dem Übersichtsaufsatz „In-fibre Bragg gra tmg sensors " von Y. J. Rao , Meas . Sei . Technol . , Vol . 8, 1991 , Sei ten 355 bi s 375 ist ein optischer Sensor auf Basis eines Faser-Bragg- Gitters bekannt. Mit Hilfe eines Faser-Bragg-Gitters laßt sich eine Langenanderung einer optischen Faser detektieren. Ein Bragg-Gitter, das zunächst m eine optische Faser eingebracht wird, ist im wesentlichen eine periodische lokale Modulation des Brechungsindex im Kern der optischen Faser. Diese Modulation des Brechungsindex im Kern wird im folgenden auch mit „Kernindex-Modulation* bezeichnet.An optical sensor based on a fiber Bragg grating is known from the review article "In-fiber Bragg graph sensors" by YJ Rao, Meas. Sei. Technol., Vol. 8, 1991, pages 355 to 375 A length change in an optical fiber can be detected with the aid of a fiber Bragg grating. A Bragg grating which is initially introduced into an optical fiber is essentially a periodic local modulation of the refractive index in the core of the optical fiber. This modulation of the refractive index in Kern is also referred to below as “core index modulation *.
Die lokal begrenzte Kernindex-Modulation stellt eine Diskontinuität für ein auftreffendes Lichtsignal dar, an der es zu Teil- oder auch Totalreflexionen bei bestimmten Wellenlangen kommt. Welche Wellenlange oder welcher Wellenlangenanteil hiervon betroffen ist, hangt dabei von der Ausbildung derThe locally limited core index modulation represents a discontinuity for an incident light signal, at which partial or total reflections occur at certain wavelengths. Which wavelength or which wavelength portion is affected depends on the formation of the
Kernindex-Modulation des Bragg-Gitters ab. Durch die Ausbildung der Kernindex-Modulation wird das Bragg-Gitter folglich auf eine bestimmte Wellenlange oder ein bestimmtes Wellen^- langenspektrum abgestimmt.Core index modulation of the Bragg grating. By forming the core index modulation, the Bragg grating is consequently tuned to a certain wavelength or a certain wavelength spectrum.
Da eine Langenanderung der optischen Faser die lokale Periode der Kernindex-Modulation beeinflußt, verändert sich auch der Wellenlangengehalt sowohl des reflektierten als auch des durchgelassenen, d.h. des transmittierten Lichtsignals. Die entsprechende Modifikation im Wellenlangengehalt kann somit als Maß für die Langenanderung der optischen Faser heran- gezogen werden. Mit diesem Meßprinzip lassen sich nebenSince a change in length of the optical fiber affects the local period of the core index modulation, the wavelength content of both the reflected and the transmitted, i.e. of the transmitted light signal. The corresponding modification in the wavelength content can thus be used as a measure of the change in length of the optical fiber. With this measuring principle, in addition to
Dehnung/Stauchung auch andere physikalische Meßgroßen wie Temperatur, Druck, Schall, Beschleunigung, hohe Magnetfelder auch Kraft detektieren. Eine Ausfuhrungsform des Sensors auf Basis des Faser-Bragg-Gitters für eine Detektion eines elek- trischen Felds bzw. einer elektrischen Spannung ist dem genannten Übersichtsaufsatz nicht zu entnehmen.Elongation / compression also detect other physical parameters such as temperature, pressure, sound, acceleration, high magnetic fields and force. An embodiment of the sensor based on the fiber Bragg grating for the detection of an electrical field or an electrical voltage cannot be found in the above-mentioned review article.
Die Aufgabe der Erfindung besteht nun m der Angabe einer Vorrichtung und eines Verfahrens der einleitend jeweils bezeichneten Art, die eine gegenüber dem Stand der Technik verbesserte bzw. vereinfachte gleichzeitige Detektion von elektrischem Strom und einer Komponente eines elektrischen Felds ermöglichen. Insbesondere sollen dabei optische Komponenten eingespart werden.The object of the invention is to provide a device and a method of the type described in the introduction, which enable simultaneous detection of electrical current and a component of an electrical field to be improved or simplified compared to the prior art. In particular, optical components should be saved.
Zur Losung der die Vorrichtung betreffenden Teilaufgabe wird eine Vorrichtung entsprechend den Merkmalen des unabhängigen Patentanspruchs 1 angegeben.To solve the subtask relating to the device, a device is specified according to the features of independent claim 1.
Bei der erfmdungsgemaßen Vorrichtung zur optischen Erfassung eines elektrischen Stroms und mindestens einer Komponente eines elektrischen Felds handelt es sich um eine Vorrichtung, welche einen Lichtpfad mit einer optischen Reihenschaltung von - mindestens einem stromempfmdlichen Faraday-Element und - mindestens einem auf die mindestens eine Komponente des elektrischen Felds empfindlichen Elements umfaßt. Zur Losung der das Verfahren betreffenden Teilaufgabe wird ein Verfahren entsprechend den Merkmalen des unabhängigen Patentanspruchs 13 angegeben.The device according to the invention for optically detecting an electrical current and at least one component of an electric field is a device which has a light path with an optical series connection of - at least one current-sensitive Faraday element and - at least one on the at least one component of the electrical Field sensitive element includes. To solve the subtask relating to the method, a method is specified according to the features of independent claim 13.
Bei dem erfmdungsgemaßen Verfahren zur optischen Erfassung eines elektrischen Stroms und mindestens einer Komponente eines elektrischen Felds handelt es sich um ein Verfahren, bei welchem a) e Sendelichtsignal erzeugt und m eine optische Reihen¬ schaltung aus mindestens einem strome pfmdlichen Faraday-Element und aus mindestens einem auf die mindestens eine Komponente des elektrischen Felds empfindlichen Element eingespeist wird, zumindest em Anteil des Sendelichtsignals in sukzessiver Abfolge b) durch das mindestens eine stromempfmdliche Faraday- Element einem Polarisationszustand und c) durch das mindestens eine auf die mindestens eine Kom- ponente des elektrischen Felds empfindliche Element in einer von dem Polarisationszustand verschiedenen opti¬ schen Eigenschaft beeinflußt wird, und d) aus der Beeinflussung der von dem Polarisationszustand verschiedenen Eigenschaft mindestens eine erste Meßgroße für die mindestens eine Komponente des elektrischen Felds und e) aus der Beeinflussung des Polarisationszustands eine zweite Meßgroße für den elektrischen Strom abgeleitet wird.In the inventive shaped A method of optically detecting an electric current and at least one component of an electric field, there is a method in which a) e transmission light signal is generated and m an optical rows ¬ circuit of at least one strome pfmdlichen Faraday element and at least one the at least one component of the electric field sensitive element is fed, at least em portion of the transmitted light signal in a successive sequence b) by the at least one current sensitive Faraday element having a polarization state and c) by the at least one to the at least one component of the electric field -sensitive element in a direction different from the polarization state opti ¬'s property is influenced, and d) from influencing the polarization state different from the property of at least a first measured quantity for the at least one component of the electric field, and e) from the Bee Influence of the polarization state, a second measurand for the electrical current is derived.
Die Erfindung beruht dabei auf der Erkenntnis, daß sich die optische Erfassung eines elektrischen Stroms und einer Komponente eines elektrischen Felds in vorteilhafter Weise ko - binieren laßt, indem em einziges Lichtsignal sowohl durch mindestens e stromempfindliches Faraday-Element als auch durch mindestens em auf die mindestens eine Komponente des elektrischen Felds empfindliches Element hindurchlauft und durch die jeweilige zu messende Große beeinflußt wird. Die Komponente des elektrischen Felds wird im folgenden auch mit „Feldkomponentew bezeichnet.The invention is based on the knowledge that the optical detection of an electric current and a component of an electric field can be combined in an advantageous manner by em a single light signal both by at least one current sensitive Faraday element and by at least one em to the at least one a component of Electrical field sensitive element runs through and is influenced by the respective size to be measured. The component of the electric field is also referred to below as “field component w .
Das Faraday-Element und das auf die mindestens eine Feldkom¬ ponente empfindliche Element liegen in einer optischen Reihenschaltung vor, wobei die Reihenfolge in diesem Zusammen¬ hang keine Rolle spielt. Das Faraday-Element und das auf die Feldkomponente empfindliche Element beeinflussen dabei verschiedene und vor allem auch selektiv detektierbare Parameter des eingespeisten Sendelichtsignals. Diese selektiv detek- tierbaren Parameter können z.B. der Polarisationszustand und der Wellenlangengehalt des Sendelichtsignals sein. Der elek- trische Strom und die Feldkomponente smd also auch mit der kombinierten Anordnung von Faraday-Element und von auf die Feldkomponente empfindlichem Element in der optischen Reihenschaltung separat, d.h. einzeln, erfaßbar.The Faraday element and the component on the at least one Feldkom ¬ sensitive element are in optical series circuit, the sequence in this context ¬ hang does not matter. The Faraday element and the element sensitive to the field component influence various and, above all, selectively detectable parameters of the transmitted light signal. These selectively detectable parameters can be, for example, the polarization state and the wavelength content of the transmitted light signal. The electrical current and the field component smd can thus also be detected separately, ie individually, with the combined arrangement of the Faraday element and the element sensitive to the field component in the optical series connection.
Verglichen mit einem komplett voneinander unabhängigenCompared to a completely independent one
Betrieb des Faraday-Elements und des auf die Feldkomponente empfindlichen Elements werden bei der erfmdungsgemaßen Losung optische Komponenten wie z.B. eine zweite Lichtquelle oder gesonderte zu- bzw. abfuhrende Lichtwellenleiter e - gespart. Die erfmdungsgemaße Vorrichtung zur Erfassung von elektrischem Strom und einer Feldkomponente kann somit preiswerter gefertigt werden und hat außerdem auch einen kleineren Platzbedarf als zwei separate Vorrichtungen.Operation of the Faraday element and the element sensitive to the field component are optical components in the solution according to the invention, e.g. a second light source or separate supply or discharge optical fibers e - saved. The device according to the invention for detecting electrical current and a field component can thus be manufactured more cheaply and also has a smaller space requirement than two separate devices.
Damit eignet sie sich besonders gut für einen Einsatz m der elektrischen Energieversorgung. Wegen ihrer geringen Baugroße laßt sich die Vorrichtung besonders einfach m andere bestehende Betriebsmittel wie beispielsweise einen Freiluft- Leistungsschalter bzw. eine gasisolierte Schaltanlage mte- gπeren. Besondere Ausgestaltungen und Weiterbildungen der Vorrichtung und des Verfahrens nach der Erfindung ergeben sich aus den jeweils abhangigen Unteranspruchen.It is therefore particularly well suited for use in electrical energy supply. Because of its small size, the device can be merged particularly easily with other existing equipment, such as an outdoor circuit breaker or a gas-insulated switchgear. Special refinements and developments of the device and the method according to the invention result from the respective dependent subclaims.
Vorteilhaft ist eine Ausfuhrungsvariante, bei der das mindestens eine auf die mindestens eine Feldkomponente empfindliche Element als Bragg-Element ausgebildet ist. Aufgrund der bei Bragg-Elementen allgemein üblichen Codierung der Meß- mformation m dem Wellenlangengehalt resultiert bei dieser Ausfuhrungsvariante eine verglichen mit dem Stand der Technik deutlich reduzierte Empfindlichkeit gegenüber Störgrößen. Die relevanten Störgrößen beeinflussen die Intensität eines zur Übertragung der Meßinformation verwendeten Lichtsignals starker als den Wellenlangengehalt.An embodiment variant is advantageous in which the at least one element sensitive to the at least one field component is designed as a Bragg element. Because of the coding of the measurement information in the wavelength content that is generally customary with Bragg elements, this embodiment variant has a significantly reduced sensitivity to disturbance variables compared to the prior art. The relevant disturbance variables influence the intensity of a light signal used to transmit the measurement information more than the wavelength content.
In einer weiteren Ausfuhrungsform der Vorrichtung enthalt das Bragg-Element einen Piezokorper, der aufgrund seiner Piezoelektrizität mit einer Formänderung auf die mindestens eine Feldkomponente reagiert. Em Lichtwellenleiter ist mit dem Piezokorper mechanisch so verbunden, daß die Formänderung des Piezokorpers eine Langenanderung des Lichtwellenleiters bewirkt. Der Lichtwellenleiter kann dabei sowohl em zuführender als auch em abführender Lichtwellenleiter des Faraday- Elements sein. Die Reihenfolge der Anordnung des Faraday- Elements und des Bragg-Elements spielt keine entscheidende Rolle. Innerhalb des Lichtwellenleiters befindet sich genau an der Stelle, die durch die Formänderung des Piezokorpers m der Lange verändert wird, em Bragg-Gitter mit vorbestimmter Bragg-Wellenlange . Durch die lokale Langenanderung des Licht- Wellenleiters verändert sich auch die dem Bragg-Gitter zugrundeliegende Kernmdex-Modulation, so daß von einem Sendelichtsignal, das auf das Bragg-Gitter trifft, em anderer Wellenlangenanteil reflektiert wird als bei Abwesenheit der Feldkomponente. Unter dem Einfluß der Feldkomponente wird folglich sowohl der durch das Bragg-Element hindurchlaufende Anteil des Sendelichtsignals, der hier mit transmittiertem Lichtsignal bezeichnet wird, als auch der am Bragg-Element reflektierte Anteil des Sendelichtsignals, der hier als reflektiertes Lichtsignal bezeichnet wird, im Wellenlangengehalt beeinflußt. Das reflektierte Lichtsignal besteht im wesentlichen aus einer Wellenlange, die der Bragg-Wellenlange entspricht. Das transmittierte Lichtsignal weist dagegen m seinem Wellenlangenspektrum gerade an der Stelle der Bragg- Wellenlange eine Lücke auf.In a further embodiment of the device, the Bragg element contains a piezo body, which due to its piezoelectricity reacts with a change in shape to the at least one field component. An optical fiber is mechanically connected to the piezo body in such a way that the change in shape of the piezo body causes a change in length of the optical fiber. The optical waveguide can be both an infeed and an outfeed optical waveguide of the Faraday element. The order of the arrangement of the Faraday element and the Bragg element does not matter. Within the optical waveguide there is a Bragg grating with a predetermined Bragg wavelength exactly at the point which is changed by the change in shape of the piezo body m the length. The local change in the length of the optical waveguide also changes the Kernmdex modulation on which the Bragg grating is based, so that a different wavelength component is reflected by a transmitted light signal which strikes the Bragg grating than in the absence of the field component. Under the influence of the field component, both the portion of the transmitted light signal which passes through the Bragg element, which is referred to here as the transmitted light signal, and that at the Bragg element reflected portion of the transmitted light signal, which is referred to here as a reflected light signal, is influenced in the wavelength content. The reflected light signal essentially consists of a wavelength that corresponds to the Bragg wavelength. In contrast, the transmitted light signal has a gap in its wavelength spectrum precisely at the location of the Bragg wavelength.
In einer weiteren bevorzugten Ausfuhrungsform besteht der Piezokorper aus Einkristallen wie Quarz, LithiumniobatIn a further preferred embodiment, the piezo body consists of single crystals such as quartz, lithium niobate
(LιNb03) oder Lithiumtantalat (LιTa03) , einem piezoelektrischen Polymer wie z.B. Polyvmylidenfluorid (PVDF) oder auch einer Piezokeramik. Da die einsetzbaren piezoelektrischen Einkristalle alle anisotropes Verhalten aufweisen, kann der Piezokorper mit verschiedener Orientierung aus dem betreffenden Kristall herausgeschnitten werden.(LιNb0 3 ) or lithium tantalate (LιTa0 3 ), a piezoelectric polymer such as polyvinylidene fluoride (PVDF) or a piezoceramic. Since the piezoelectric single crystals that can be used all have anisotropic behavior, the piezo body can be cut out of the relevant crystal with different orientations.
Bevorzugt ist ebenfalls eine Ausfuhrungsvariante, m der der Lichtpfad, der die optische Reihenschaltung des Faraday- Elements und des auf die Feldkomponente empfindlichen Elements beinhaltet, mehrere Lichtwellenleiter umfaßt. Insbesondere können diese Lichtwellenleiter einen unterschiedlichen Lichtwellenleitertyp aufweisen. Bevorzugt werden dabei Lichtwellenleiter Form einer Multimode-Faser, einer Monomode- Faser, einer polarisierenden Faser oder auch einer polarisa- tionserhaltenden Faser eingesetzt.Also preferred is an embodiment variant in which the light path, which contains the optical series connection of the Faraday element and the element sensitive to the field component, comprises a plurality of optical fibers. In particular, these optical waveguides can have a different type of optical waveguide. Optical waveguides in the form of a multimode fiber, a single-mode fiber, a polarizing fiber or else a polarization-maintaining fiber are preferably used.
In einer Ausfuhrungsvariante smd m den zu- bzw. abfuhrenden Lichtwellenleitern des Faraday-Elements mehrere Bragg-Ele- mente mit Bragg-Gittern jeweils unterschiedlicher Bragg-Wellenlange integriert. Die einzelnen Bragg-Elemente reagieren dabei auf jeweils verschiedene Feldkomponenten, die entlang des zu- bzw. abfuhrenden Lichtwellenleiters anstehen. Vorteilhaft ist deshalb eine andere Ausgestaltung der Vorπch- tung, bei der eine Breitbandlichtquelle vorgesehen ist, deren emittiertes Lichtspektrum mindestens alle Bragg-Wellenlangen der m den zu- bzw. abführenden Lichtwellenleiter eingebrach- ten Bragg-Gitter umfaßt. Diesbezüglich geeignete Breitband- lichtquellen smd eine SLD (Superlummeszenzdiode) , eine ELED (edge-emittmg light emitt g diode) , eine SFS (superfluores- cent fibre source) oder em TFL (tuneable fibre laser) . Das emittierte Wellenlangenspektrum dieser Lichtquellen hat dann vorzugsweise eine Halbwertsbreite von bis zu 200 nm. Lichtquellen mit einem noch größeren Emissionsspektrum smd ebenfalls geeignet. Im Zusammenhang mit einem TFL ist unter dem Emissionsspektrum hier derjenige Wellenlangenbereich zu ver- stehen, den der TFL überstreicht. Es können auch mehr als eine Lichtquelle vorgesehen sein, die zeitlich und/oder spektral versetzt zueinander Licht den Lichtpfad einspeisen.In one embodiment variant, several Bragg elements with Bragg gratings, each with a different Bragg wavelength, are integrated in the incoming and outgoing optical waveguides of the Faraday element. The individual Bragg elements react to different field components that are present along the incoming and outgoing optical waveguide. Another embodiment of the device is therefore advantageous, in which a broadband light source is provided, the emitted light spectrum of which introduces at least all Bragg wavelengths of the optical fibers leading to and from the fiber. ten Bragg grating. Suitable broadband light sources in this regard are an SLD (superluminescent diode), an ELED (edge-emitting light-emitting g diode), an SFS (superfluorescent fiber source) or an TFL (tunable fiber laser). The emitted wavelength spectrum of these light sources then preferably has a half width of up to 200 nm. Light sources with an even larger emission spectrum smd are also suitable. In connection with a TFL, the emission spectrum here means the wavelength range that the TFL sweeps over. More than one light source can also be provided, which feed light into the light path at a time and / or spectrally offset from one another.
Vorteilhaft ist eine Ausfuhrungsform, die eine wellenlangen- selektive Auswertung zumindest des durch das Faraday-Element in seinem Polarisationszustand und durch mindestens em Bragg-Element m seinem Wellenlangengehalt beeinflußten Anteils des Sendelichtsignals vornimmt. Durch eine wellen- langenselektive Aufteilung über ein optisches Filter oder em Spektrometer entsprechend den jeweiligen Bragg-Wellenlangen kann die Meßinformation über die an dem jeweiligen Bragg- Element anstehende Feldkomponente und über den durch das Faraday-Element hindurchfließenden elektrischen Strom er- mittelt werden.An embodiment is advantageous which carries out a wavelength-selective evaluation of at least the portion of the transmitted light signal which is influenced by the Faraday element in its polarization state and by at least one Bragg element in its wavelength content. The measurement information about the field component present at the respective Bragg element and about the electrical current flowing through the Faraday element can be determined by a wavelength-selective division via an optical filter or a spectrometer in accordance with the respective Bragg wavelengths.
Üblicherweise ist m dem Lichtpfad nur em einziges Faraday- Element vorgesehen. Es gibt jedoch auch Ausfuhrungsformen der Vorrichtung, m denen zwei oder mehr Faraday-Elemente von dem Sendelichtsignal durchlaufen werden.Usually only one Faraday element is provided in the light path. However, there are also embodiments of the device in which two or more Faraday elements are passed through by the transmitted light signal.
Vorteilhafte Ausfuhrungsformen des Verfahrens, die sich aus den entsprechenden Unteranspruchen ergeben, weisen im wesentlichen die gleichen Vorteile auf wie die obengenannten e- weils korrespondierenden Ausgestaltungen der Vorrichtung. Besonders vorteilhaft ist eine Variante des Verfahrens, bei der neben der mindestens einen ersten Meßgroße für die mindestens eine Feldkomponente und der zweiten Meßgroße für den elektrischen Strom außerdem eine dritte Meßgroße für eine elektrische Spannung eines Stromleiters, in dem der elektrische Strom fließt, ermittelt wird. Diese dritte Meßgroße wird dabei aus den ersten Meßgroßen für die Feldkomponenten abgeleitet. Da Feldkomponenten entlang des zu- bzw. abfuhrenden Lichtwellenleiters gemessen werden, kann die als Lmienmte- gral des elektrischen Feldverlaufs zwischen dem Stromleiter und einem Punkt auf Erdpotential, beispielsweise dem Ort der Auswerteeinheit, definierte elektrische Spannung durch diese gemessenen Feldkomponenten angenähert werden. Dazu wird das Linienintegral durch eine Summation der mit Abmessungen der jeweiligen Piezokorper gewichteten ersten Meßgroßen für die Feldkomponenten ersetzt. Das Verfahren liefert somit jeweils eine Meßgroße für den elektrischen Strom und für die elektrische Spannung.Advantageous embodiments of the method, which result from the corresponding subclaims, have essentially the same advantages as the above-mentioned corresponding configurations of the device. A variant of the method is particularly advantageous in which, in addition to the at least one first measurement variable for the at least one field component and the second measurement variable for the electrical current, a third measurement variable for an electrical voltage of a current conductor in which the electrical current flows is also determined. This third measurand is derived from the first measurands for the field components. Since field components are measured along the incoming or outgoing optical waveguide, the electrical voltage defined as the integral of the electrical field profile between the current conductor and a point at earth potential, for example the location of the evaluation unit, can be approximated by these measured field components. For this purpose, the line integral is replaced by a summation of the first measured quantities for the field components, weighted with the dimensions of the respective piezo bodies. The method thus provides a measurement variable for the electrical current and for the electrical voltage.
Bevorzugte Ausfuhrungsbeispiele werden nunmehr anhand derPreferred exemplary embodiments are now based on the
Zeichnung naher erläutert. Zur Verdeutlichung ist die Zeichnung nicht maßstäblich ausgeführt und gewisse Merkmale smd schematisiert dargestellt. Im einzelnen zeigenDrawing explained in more detail. For clarification, the drawing is not drawn to scale and certain features are shown schematically. Show in detail
Figuren 1 und 2 Vorrichtungen zur optischen Erfassung eines elektrischen Stroms über eine Faserspule und von Feldkomponenten über Bragg-Elemente, Figur 3 eine weitere Vorrichtung zur optischen Erfassung eines elektrischen Stroms über einen massiven Glasring und einer Feldkomponente über em Bragg-Element und Figur 4 em Bragg-Element zur optischen Erfassung einer Feldkomponente.Figures 1 and 2 devices for optical detection of an electric current via a fiber coil and of field components via Bragg elements, Figure 3 shows another device for optical detection of an electric current via a solid glass ring and a field component via a Bragg element and Figure 4 em Bragg -Element for the optical detection of a field component.
Einander entsprechende Teile smd in den Figuren 1 bis 4 mit denselben Bezugszeichen versehen. Figur 1 zeigt eine Vorrichtung zur optischen Erfassung eines elektrischen Stroms I und von Komponenten E (mit 1 < l < n) eines elektrischen Felds, die hier auch als Feldkomponenten Ex bezeichnet werden. Der Laufindex „l* nimmt aus der Menge der natürlichen Zahlen Werte von 1 bis n an. Die wesentlichen sensitiven Bestandteile der Vorrichtung smd em stromempfmdliehes Faraday-Element F in Form einer Faserspule und mehrere Bragg-Elemente B1 (mit 1 < l < n) , die jeweils auf die Feldkomponente El t die an dem jeweiligen Bragg-Element B, ansteht, empfindlich reagieren. Der elektrische Strom I fließt m einem Stromleiter 50, an dem bezogen auf Erdpotential eine elektrische Spannung U ansteht. Die Bragg-Elemente B und das Faraday-Element F smd m dem Ausfuhrungsbeispiel von Figur 1 optisch hmteremandergeschaltet . Em m diese Reihenschaltung eingespeistes Sendelichtsignal LS durchlauft zunächst die Bragg-Elemente BL und dann das Faraday-Element F. In den Bragg-Elementen Bx erfahrt das Sendelichtsignal LS eine Änderung m einem Wellenlangengehalt und m dem Faraday- Element F eine Änderung in einem Polarisationszustand.Corresponding parts smd in Figures 1 to 4 provided with the same reference numerals. FIG. 1 shows a device for optically detecting an electrical current I and components E (with 1 <1 <n) of an electrical field, which are also referred to here as field components E x . The running index “l *” takes values from 1 to n from the set of natural numbers. The substantially sensitive components of the device smd em stromempfmdliehes Faraday element F in the form of a fiber coil and a plurality of Bragg elements B 1 (1 <l <n), the LT respectively on the field component E, the respective at Bragg element B is present, , react sensitively. The electrical current I flows in a current conductor 50, at which an electrical voltage U is present in relation to earth potential. The Bragg elements B and the Faraday element F are connected optically to the embodiment of FIG. In this series connection, the transmitted light signal LS passes first through the Bragg elements B L and then through the Faraday element F. In the Bragg elements B x, the transmitted light signal LS undergoes a change in a wavelength content and m in the Faraday element F a change in one Polarization state.
Das Sendelichtsignal LS wird von einer Breitbandlichtquelle 20, die als Superlumineszenzdiode (SLD) ausgebildet ist, erzeugt und über einen Koppler 40 m einen zufuhrenden Lichtwellenleiter 11 des Faraday-Elements F eingespeist. Dieser zufuhrende Lichtwellenleiter 11 ist im Ausfuhrungsbeispiel von Figur 1 als Monomode-Faser ausgebildet. Die Bragg-Elemente Bx smd in diesen zufuhrenden Lichtwellenleiter 11 integriert .The transmitted light signal LS is generated by a broadband light source 20, which is designed as a superluminescent diode (SLD), and is fed via a coupler 40 m to a supplying optical waveguide 11 of the Faraday element F. In the exemplary embodiment of FIG. 1, this feeding optical waveguide 11 is designed as a single-mode fiber. The Bragg elements B x smd are integrated in this supplying optical waveguide 11.
Die Bragg-Elemente Bx werden durch Einbringen jeweils unterschiedlicher Kernmdex-Modulationen m den zufuhrenden Lichtwellenleiter 11 auf voneinander verschiedene Bragg-Wellen- langen λx (mit 1 < l < n) abgestimmt. Dies erfolgt durch jeweils unterschiedliche örtliche Modulationsperioden. Das Sendelichtsignal LS wird dann im Spektralbereich der jeweiligen Wellenlange λx am zugehörigen Bragg-Element Bx zumindest teilweise reflektiert. Durch die Reflexion des Sende- lichtsignals LS an den einzelnen Kernmdex-Modulationen der jeweiligen Bragg-Elemente Bx lauft em reflektiertes Licht- signal LR mit einem Wellenlangengehalt, der die einzelnen Bragg-Wellenlangen λ„ umfaßt, m Richtung der Breitbandlicht- quelle 20 zurück. Am Koppler 40 wird das reflektierte Licht- signal LR jedoch m Richtung einer Auswerteeinheit 30 umgeleitet .The Bragg elements B x are matched to different Bragg wavelengths λ x (with 1 <1 <n) by introducing different Kernmdex modulations in each case into the supplying optical waveguide 11. This is done by different local modulation periods. The transmitted light signal LS is then at least partially reflected in the spectral range of the respective wavelength λ x at the associated Bragg element B x . By reflecting the broadcast Light signal LS at the individual Kernmdex modulations of the respective Bragg elements B x runs back a reflected light signal LR with a wavelength content, which comprises the individual Bragg wavelengths λ ", in the direction of the broadband light source 20. At the coupler 40, however, the reflected light signal LR is redirected in the direction of an evaluation unit 30.
Am von der Breitbandlichtquelle 20 abgewandten Ende der Strecke des zufuhrenden Lichtwellenleiters 11, innerhalb derer die Bragg-Elemente Bλ integriert smd, liegt em trans- mittiertes Lichtsignal LT vor, das sich aus Wellenlangen- anteilen des Sendelichtsignals LS zusammensetzt, die von den Bragg-Wellenlangen λx verschieden smd. Diese Wellenlangen- anteile passieren alle Bragg-Elemente Bx ungehindert. Das transmittierte Lichtsignal LT weist somit em mit Lucken versehenes Wellenlangenspektrum auf, wobei sich die Lucken gerade an den Stellen der einzelnen Bragg-Wellenlangen λ befinden.At the end of the section of the supplying optical waveguide 11 facing away from the broadband light source 20, within which the Bragg elements B λ are integrated, there is an emitted light signal LT, which is composed of wavelength components of the transmitted light signal LS, which are generated by the Bragg Wavelengths λ x different smd. These wavelength components pass through all Bragg elements B x unhindered. The transmitted light signal LT thus has a wavelength spectrum provided with gaps, the gaps being located precisely at the locations of the individual Bragg wavelengths λ.
Werden die Bragg-Elemente Bx mit einer Meßgroße, im vorliegenden Fall mit den Feldkomponenten El f beaufschlagt, so resultiert eine Beeinflussung des Wellenlangengehalts sowohl des reflektierten als auch des transmittierten Lichtsignals LR und LT. Beim reflektierten Lichtsignal LR verschieben sich die einzelnen Bragg-Wellenlangen λ_ selbst, beim transmittierten Lichtsignal LT dagegen die besagten Lucken im Wellenlangenspektrum. Da auch das transmittierte Lichtsignal LT im weiteren Verlauf der Auswerteeinheit 30 zugeführt wird, er- moglicht die Detektion beider Verschiebungen m der Auswerteeinheit 30 eine redundante Bestimmung von ersten Meßgroßen Mlx für die Feldkomponenten Ex . In der Auswerteeinheit 30 wird dazu aus den jeweiligen Verschiebungen auf die zugrundeliegende Feldkomponente Ex zuruckgeschlossen.If the Bragg elements B x are subjected to a measurement variable, in the present case the field components E lf, the wavelength content of both the reflected and the transmitted light signals LR and LT is influenced. With the reflected light signal LR, the individual Bragg wavelengths λ_ shift themselves, with the transmitted light signal LT, however, said gaps in the wavelength spectrum. Since the transmitted light signal LT is also fed to the evaluation unit 30 in the further course, the detection of both displacements m of the evaluation unit 30 enables a redundant determination of first measured quantities Ml x for the field components E x . For this purpose, in the evaluation unit 30, the respective field component E x is inferred from the respective displacements.
Ehe das transmittierte Lichtsignal LT die Auswerteeinheit 30 erreicht, durchlauft es zunächst das Faraday-Element F. Vor Eintritt in das Faraday-Element F wird das transmittierte. Lichtsignal LT m einem polarisierenden Lichtwellenleiter 12 linear polarisiert. In der den Stromleiter 50 mit mehreren Windungen umgebenden Faserspule des Faraday-Ele ents F wird der lineare Polarisationszustand dann unter dem Einfluß des im Stromleiter 50 fließenden elektrischen Stroms I um einen Faraday-Drehwmkel gedreht. Der resultierende Faraday-Dreh- wmkel ist abhangig von dem Material der Faserspule, der Anzahl der Windungen sowie dem elektrischen Strom I. Am Ausgang des Faraday-Elements F liegt em stromcodiertes transmittiertes Lichtsignal LT' vor. Dieses stromcodierte transmittierte Lichtsignal LT' enthalt m seinem Wellenlangengehalt codierte Meßinformationen über die Feldkomponenten Ex und eine m seinem Polarisationszustand codierte Meßinformation über den elektrischen Strom I. Das stromcodierte transmittierte Lichtsignal LT' wird über einen abfuhrenden Lichtwellenleiter 13 des Faraday-Elements F der Auswerteemheit 30 zugeführt. Der abfuhrende Lichtwellenleiter 13 ist m der Vorrichtung von Figur 1 als polarisa- tionserhaltender Lichtwellenleiter ausgeführt.Before the transmitted light signal LT reaches the evaluation unit 30, it first passes through the Faraday element F. Vor Entry into the Faraday element F becomes the transmitted one. Light signal LT m linearly polarized a polarizing optical waveguide 12. In the fiber coil of the Faraday-Ele ent F surrounding the current conductor 50 with several turns, the linear polarization state is then rotated about a Faraday rotation under the influence of the electrical current I flowing in the current conductor 50. The resulting Faraday rotation is dependent on the material of the fiber spool, the number of turns and the electrical current I. At the output of the Faraday element F there is a current-coded transmitted light signal LT '. This current-coded transmitted light signal LT 'contains, in its wavelength content, coded measurement information about the field components E x and in its polarization state, coded measurement information about the electrical current I. The current-coded transmitted light signal LT' is transmitted via a discharging optical waveguide 13 of the Faraday element F of the evaluation unit 30 fed. The discharging optical waveguide 13 is designed in the device of FIG. 1 as a polarization-maintaining optical waveguide.
Die Auswerteemheit 30 enthalt am Eingang zunächst Mittel zur wellenlangenselektiven Aufteilung sowohl des reflektierten Lichtsignals LR als auch des stromcodierten trans ittierten Lichtsignals LT' . Die Aufteilung erfolgt dabei in Frequenzbereiche, die jeweils nur eine einzige Bragg-Wellenlange λ^ umfassen. Aus diesen Wellenlangenbereichen lassen sich die ersten Meßgroßen M1L für die Feldkomponenten Ex bestimmen. Außerdem ist em weiterer Wellenlangenanteil vorgesehen, der keine der Bragg-Wellenlangen λ,. umfaßt. Dieser Wellenlangen- bereich dient der Ermittlung einer zweiten Meßgroße M2 für den elektrischen Strom I. Dazu besitzt die Auswerteemheit eine an sich bekannte Anordnung zur Auswertung eines Licht- signals, das die Meßinformation über den elektrischen Strom I m Form einer Codierung bzw. Modulation des Polaπsations- zustands beinhaltet. Diese Anordnung umfaßt insbesondere einen Analysator, der die Polarisationsmodulation in eine. Intensitatsmodulation umwandelt.The evaluation unit 30 initially contains means for wavelength-selective division of both the reflected light signal LR and the current-coded transmitted light signal LT 'at the input. The division is made into frequency ranges, each of which comprises only a single Bragg wavelength λ ^ . The first measured quantities M1 L for the field components E x can be determined from these wavelength ranges. Moreover em another wavelength component is provided which λ none of the Bragg wavelengths. includes. This wavelength range is used to determine a second measurement variable M2 for the electrical current I. For this purpose, the evaluation unit has a known arrangement for evaluating a light signal which contains the measurement information about the electrical current I in the form of a coding or modulation of the polarization - condition included. This arrangement includes in particular an analyzer that converts the polarization modulation into a. Converts intensity modulation.
Der zufuhrende Lichtwellenleiter 11 verlauft längs eines Verbindungswegs zwischen dem Stromleiter 50 und der Breitbandlichtquelle 20, die sich ebenso auf Erdpotential befindet wie die Auswerteemheit 30. Durch eine Linienintegration des elektrischen Felds längs dieses Verbindungswegs erhalt man folglich die elektrische Spannung U, die an dem Stromleiter 50 ansteht. Dieses Linienintegral laßt sich mit Hilfe der über die Bragg-Elemente B detektierten Feldkomponenten E. annähern. Die Annäherung erfolgt dabei durch eine Summation von Produkten aus den ersten Meßgroßen Ml. für die Feldkomponenten E1 und lokalen Abmessungen der jeweils zugehörigen Bragg-Elemente B . Diese Auswertung wird m einer Spannungs- einheit 31, die der Auswerteemheit 30 nachgeschaltet ist, durchgeführt. Als Eingangsgroße der Spannungseinheit 31 dienen dabei die ersten Meßgroßen Ml;,.. Als Ausgangsgroße liefert die Spannungseinheit 31 eine dritte Meßgroße M3 für die elek- trische Spannung U. Mit der in Figur 1 gezeigten Vorrichtung kann folglich sowohl der elektrische Strom I als auch die elektrische Spannung U detektiert und ausgewertet werden. Die Vorrichtung stellt somit einen Kombi-Wandler dar.The supplying optical waveguide 11 runs along a connection path between the current conductor 50 and the broadband light source 20, which is also at ground potential like the evaluation unit 30. By integrating the electric field along this connection path, the electrical voltage U that is present on the current conductor 50 is thus obtained pending. This line integral can be approximated with the aid of the field components E. detected via the Bragg elements B. The approximation is carried out by summing products from the first measured quantities Ml . for the field components E 1 and local dimensions of the associated Bragg elements B. This evaluation is carried out in a voltage unit 31 which is connected downstream of the evaluation unit 30. The first measured variables M1,... Serve as the input variable of the voltage unit 31 . , As the output variable, the voltage unit 31 supplies a third measurement variable M3 for the electrical voltage U. Consequently, with the device shown in FIG. 1, both the electrical current I and the electrical voltage U can be detected and evaluated. The device thus represents a combination converter.
In einer nicht gezeigten Ausfuhrungsform smd die Breitbandlichtquelle 20 nebst elektronischer Ansteuerung sowie die Auswerteemheit 30 und die Spannungseinheit 31 zu einer einzigen optoelektronischen Einheit zusammengefaßt. Insbesondere erfolgen die Berechnungen für die dritte Meßgroße M3 dann der gleichen Recheneinheit, z.B. m einem Mikroprozessor, in der auch die ersten Meßgroßen Mlx und die zweite Meßgroße M2 bestimmt werden.In one embodiment, not shown, the broadband light source 20 together with electronic control and the evaluation unit 30 and the voltage unit 31 are combined to form a single optoelectronic unit. In particular, the calculations for the third measurement variable M3 are then carried out by the same computing unit, for example in a microprocessor, in which the first measurement variables Ml x and the second measurement variable M2 are also determined.
Die m Figur 2 gezeigte Vorrichtung dient ebenfalls zur opti- sehen Erfassung des elektrischen Stroms I und der elektrischen Spannung U. Sie ähnelt m weiten Teilen der m Figur 1 gezeigten Vorrichtung. Em wesentlicher Unterschied besteht allerdings darin, daß die Bragg-Elemente Bi bei dem Ausfüh¬ rungsbeispiel von Figur 2 nicht in den zuführenden Lichtwellenleiter 11, sondern in den abführenden Lichtwellenleiter 13 integriert sind.The device shown in FIG. 2 is also used for optically detecting the electrical current I and the electrical voltage U. It is similar in large parts to the device shown in FIG. There is an essential difference However, the fact that the Bragg elements Bi are not integrated in the exporting ¬ approximately example of Figure 2 in the feeding optical waveguide 11, but in the efferent optical fiber. 13
Das Sendelichtsignal LS wird somit zunächst in das Faraday- Element F eingespeist und durch den elektrischen Strom I in seinem Polarisationszustand verändert. Am Ausgang des Faraday-Elements F liegt dann ein stromcodiertes Sendelichtsignal LS' vor. Dieses durchläuft die Bragg-Elemente Bi . An deren Ausgang steht das stromcodierte transmittierte Lichtsignal LT' an, das wiederum in die Auswerteeinheit 30 eingespeist wird. Die Auswertung erfolgt analog zu dem Ausfuhrungsbeispiel von Figur 1.The transmitted light signal LS is thus first fed into the Faraday element F and its polarization state is changed by the electrical current I. A current-coded transmission light signal LS 'is then present at the output of the Faraday element F. This passes through the Bragg elements Bi. The current-coded transmitted light signal LT 'is present at its output, which in turn is fed into the evaluation unit 30. The evaluation is carried out analogously to the exemplary embodiment in FIG. 1.
Im Unterschied zu Figur 1 enthält das Ausführungsbeispiel von Figur 2 keinen Lichtzweig, der ein reflektiertes Lichtsignal LR der Auswerteeinheit 30 zuführt. Die an den Bragg-Elementen Bi reflektierten Lichtanteile durchlaufen den polarisierenden Lichtwellenleiter 12 auf ihrem Weg zurück in Richtung Breitbandlichtquelle 20 ein zweites Mal, wobei sie eine sehr starke Dämpfung erfahren, so daß eine Auswertung in der Auswerteeinheit 30 nicht mehr sinnvoll ist.In contrast to FIG. 1, the exemplary embodiment from FIG. 2 does not contain a light branch which supplies a reflected light signal LR to the evaluation unit 30. The light components reflected on the Bragg elements Bi pass through the polarizing optical waveguide 12 a second time on their way back in the direction of the broadband light source 20, where they experience a very strong attenuation, so that an evaluation in the evaluation unit 30 is no longer useful.
In Figur 3 ist eine weitere Vorrichtung zur optischen Erfassung eines elektrischen Stroms I und einer Feldkomponente E- dargestellt. Das Faraday-Element F ist hier als massiver Glasring ausgeführt. Nach Durchlaufen des einzigen Bragg- Elements Bi verläßt das transmittierte Lichtsignal LT den hinführenden Lichtwellenleiter 11 und wird in einem massiven Polarisator 120, der der polarisierenden Faser 12 der Ausführungsbeispiele von Figur 1 und 2 entspricht, linear polarisiert. Im Anschluß daran passiert das linear polarisierte transmittierte Lichtsignal LT den den Stromleiter 50 u geben- den massiven Glasring einmal und wird dabei durch den elektrischen Strom I in seinem Polarisationszustand beeinflußt. Unmittelbar am Ausgang des Glasrings wird diese Polarisa-, tionsmodulation durch einen strahlteilenden Analysator 121 in Form eines Wollaston-Prismas eine Intensitatsmodulation überfuhrt. Der Analysator 121 erzeugt em erstes und em zweites stromcodiertes Teillichtsignal LT1' und LT2' , die die Meßinformation über den elektrischen Strom I jeweils m Form einer Intensitatsmodulation tragen.FIG. 3 shows a further device for optically detecting an electrical current I and a field component E-. The Faraday element F is designed as a solid glass ring. After passing through the single Bragg element Bi, the transmitted light signal LT leaves the leading optical waveguide 11 and is linearly polarized in a solid polarizer 120, which corresponds to the polarizing fiber 12 of the exemplary embodiments in FIGS. Subsequently, the linearly polarized transmitted light signal LT passes once through the massive glass ring giving the current conductor 50 u and is thereby influenced by the electrical current I in its polarization state. Immediately at the exit of the glass ring, this polarization modulation is converted to an intensity modulation by a beam-splitting analyzer 121 in the form of a Wollaston prism. The analyzer 121 generates first and second current-coded partial light signals LT1 'and LT2', which each carry the measurement information about the electrical current I in the form of an intensity modulation.
Das erste und zweite stromcodierte Teillichtsignal LT1' und LT2' werden über einen ersten bzw. zweiten abfuhrenden Lichtwellenleiter 131 bzw. 132 zur Auswerteemheit 30 geleitet. Der zufuhrende Lichtwellenleiter 11 und die beiden abfuhrenden Lichtwellenleiter 131 und 132 sind im gezeigten Beispiel von Figur 3 jeweils als Monomode-Fasern ausgebildet. Dies ist jedoch nicht zwingend notwendig. In einer anderen Ausfuh- rungsform können auch Multimode-Fasern verwendet werden. Bis auf die Vorverlagerung der Umsetzung der Polarisationsmodulation m die Intensitatsmodulation direkt an das Faraday- Element F ist die Auswerteemheit 30 von Figur 3 identisch mit der von Figur 1.The first and second current-coded partial light signals LT1 'and LT2' are routed to the evaluation unit 30 via a first and second discharging optical waveguide 131 and 132, respectively. In the example shown in FIG. 3, the supplying optical waveguide 11 and the two outgoing optical waveguides 131 and 132 are each designed as single-mode fibers. However, this is not absolutely necessary. In another embodiment, multimode fibers can also be used. Except for the shifting of the implementation of the polarization modulation m the intensity modulation directly to the Faraday element F, the evaluation unit 30 of FIG. 3 is identical to that of FIG. 1.
In der Vorrichtung von Figur 3 ist nur em einziges Bragg- Element Bi zur Erfassung einer einzigen Feldkomponente E-. vorgesehen. Dies bietet insbesondere dann Vorteile, wenn die Entfernung zwischen dem Stromleiter 50 und dem Erdpotential nur kurz ist. E diesbezügliches Beispiel ist eine gasiso- lierte Schaltanlage. Andererseits kann die Vorrichtung von Figur 3 auch dann zur Anwendung kommen, wenn nur eine grobe Näherung für die elektrische Spannung U erwünscht ist. Die grobe Näherung erfolgt dann nur über die eine erste Meßgroße Mli der Feldkomponente Ei.In the device of FIG. 3 there is only one Bragg element Bi for detecting a single field component E-. intended. This is particularly advantageous if the distance between the current conductor 50 and the earth potential is only short. An example in this regard is a gas-insulated switchgear. On the other hand, the device of FIG. 3 can also be used if only a rough approximation for the electrical voltage U is desired. The rough approximation then takes place only via the first measured quantity Mli of the field component Ei.
In Figur 4 ist em m den Ausfuhrungsbeispielen der Figuren 1 bis 3 eingesetztes Bragg-Element Bi zur optischen Erfassung einer Feldkomponente Ex genauer dargestellt. Das Bragg-Element Bx umfaßt einen Piezokorper Px . Dieser besitzt eine Bohrung, durch die beispielsweise der zufuhrende Lichtwellen- leiter 11 nmdurchgefuhrt ist. Der Piezokorper Px und der. zufuhrende Lichtwellenleiter 11 smd im Bereich der Bohrung mechanisch fest miteinander verbunden. Der zufuhrende Lichtwellenleiter 11 besitzt gerade m diesem Bereich em Bragg- Gitter Gi mit der vorbestimmten Bragg-Wellenlange λi . Das Bragg-Gitter Gi wird durch die oben beschriebene Kernindex- Modulation gebildet.FIG. 4 shows a Bragg element Bi used for the optical detection of a field component E x in the exemplary embodiments of FIGS. 1 to 3. The Bragg element B x comprises a piezo body P x . This has a bore through which, for example, the light wave conductor 11 nm is carried out. The Piezokorper P x and the. feeding optical fibers 11 smd mechanically firmly connected to each other in the area of the bore. The supplying optical waveguide 11 has m Bragg grating Gi with the predetermined Bragg wavelength λi in this area. The Bragg grating Gi is formed by the core index modulation described above.
Bei anderen nicht dargestellten Ausfuhrungsformen kann der zufuhrende Lichtwellenleiter 11 jedoch auch um den Piezokorper Pi gewickelt werden oder in einer Nut an einer Oberflache des Piezokorpers Px eingebettet werden. Das Bragg- Gitter Gi befindet sich auch bei diesen nicht dargestellten Ausfuhrungsformen jeweils im Kontaktbereich des zufuhrenden Lichtwellenleiters 11 mit dem Piezokorper Px .In other embodiments, not shown, the supplying optical waveguide 11 can, however, also be wrapped around the piezo body Pi or embedded in a groove on a surface of the piezo body P x . The Bragg grating Gi is also in these embodiments, not shown, in each case in the contact area of the supplying optical waveguide 11 with the piezo body P x .
Aufgrund der Piezoelektrizität des Piezokorpers Px und der festen mechanischen Verbindung mit dem zufuhrenden Lichtwellenleiter 11 ruft die zu messende Feldkomponente El zu- nächst eine Formänderung des Piezokorpers Pi und infolge eine Langenanderung des zufuhrenden Lichtwellenleiters 11 hervor. Diese Langenanderung fuhrt zu einer Modifikation der Kern- mdex-Modulation im Bragg-Gitter Gx, so daß sich schließlich die oben bereits angesprochenen Verschiebungen im Wellen- langengehalt sowohl des reflektierten Lichtsignals LR als auch des transmittierten Lichtsignals LT ergeben. Diese Verschiebungen smd dann jeweils proportional zur ursächlichen Feldkomponente El. Im vorliegenden Fall besteht der Piezokorper Px aus Quarz. Due to the piezoelectricity of the piezo body P x and the fixed mechanical connection to the supplying optical waveguide 11, the field component El to be measured first causes a change in shape of the piezo body Pi and as a result of a change in length of the supplying optical waveguide 11. This change in length leads to a modification of the Kernmdex modulation in the Bragg grating G x , so that the shifts in the wavelength content of the reflected light signal LR as well as of the transmitted light signal LT which have already been mentioned above result. These shifts smd then proportional to the causal field component El. In the present case, the piezo body P x consists of quartz.

Claims

Patentansprüche claims
1. Vorrichtung zur optischen Erfassung eines elektrischen Stroms (I) und mindestens einer Komponente (E^E^E eines elektrischen Felds, umfassend einen Lichtpfad mit einer optischen Reihenschaltung von1. Device for the optical detection of an electric current (I) and at least one component (E ^ E ^ E of an electric field, comprising a light path with an optical series connection of
- mindestens einem stromempfindlichen Faraday-Element (F) und- At least one current sensitive Faraday element (F) and
- mindestens einem auf die mindestens eine Komponente des elektrischen Felds empfindlichen Elements (B B^B .- At least one element sensitive to the at least one component of the electric field (B B ^ B.
2. Vorrichtung nach Anspruch 1, d a d u r c h g e k e n n z e i c h n e t , daß der Lichtpfad mehrere Lichtwellenleiter (11,12,13,131,132), insbesondere unterschied- liehen Lichtwellenleitertyps, enthalt.2. Device according to claim 1, so that the light path contains a plurality of optical fibers (11, 12, 13, 131, 132), in particular different types of optical fibers.
3. Vorrichtung nach Anspruch 2, d a d u r c h g e k e n n z e i c h n e t , daß die einzelnen Lichtwellenleiter (11,12,13,131,132) als Multimode-Faser, Monomode- Faser, polarisierende Faser oder als polarisationserhaltende Faser ausgebildet smd.3. Apparatus according to claim 2, d a d u r c h g e k e n n z e i c h n e t that the individual optical fibers (11,12,13,131,132) as a multimode fiber, monomode fiber, polarizing fiber or as a polarization-maintaining fiber smd.
4. Vorrichtung nach Anspruch 2 oder 3, d a d u r c h g e k e n n z e i c h n e t , daß das mindestens eine auf die mindestens eine Komponente (E E^En) des elektrischen4. Apparatus according to claim 2 or 3, characterized in that the at least one of the at least one component (EE ^ E n ) of the electrical
Felds empfindliche Element m einen zufuhrenden Lichtwellenleiter (11) oder in einen abfuhrenden Lichtwellenleiter (13) des Faraday-Elements (F) integriert ist.Field sensitive element m a supplying optical waveguide (11) or in an outgoing optical waveguide (13) of the Faraday element (F) is integrated.
5. Vorrichtung nach einem der vorhergehenden Ansprüche, d a d u r c h g e k e n n z e i c h n e t , daß das auf die mindestens eine Komponente des elektrischen Felds empfindliche Element als Bragg-Element (B^B^B ausgeführt ist.5. Device according to one of the preceding claims, characterized in that on the at least one component of the electric field sensitive element is designed as a Bragg element (B ^ B ^ B.
6. Vorrichtung nach Anspruch 4 und 5, d a d u r c h g e k e n n z e i c h n e t , daß das Bragg-Element einen feldsensitiven Piezokorper (Pi), der mechanisch mit dem zu- bzw. abfuhrenden Lichtwellenleiter (11, 13; in Verbindung steht, sowie em in den zu- bzw. abfuhrenden Lichtwellenleiter (11, 13) eingebrachtes Bragg-Gitter (Gi) mit vorbestimmter Bragg-Wellenlange (λx) umfaßt.6. Apparatus according to claim 4 and 5, characterized in that the Bragg element a field-sensitive piezo body (Pi), which is mechanically connected to the incoming and outgoing optical waveguide (11, 13; as well as em into the incoming and outgoing optical waveguide (11, 13) Bragg grating (Gi) with predetermined Bragg wavelength (λ x ).
7. Vorrichtung nach Anspruch 6, d a d u r c h g e k e n n z e i c h n e t , daß der Piezokorper (Px) aus einem piezoelektrischen Material, insbesondere aus einem Einkristall wie Quarz, LιNb03, LιTa03, einem Polymer oder einer Piezokeramik, besteht.7. The device according to claim 6, characterized in that the piezo body (P x ) consists of a piezoelectric material, in particular of a single crystal such as quartz, LιNb0 3 , LιTa0 3 , a polymer or a piezoceramic.
8. Vorrichtung nach einem der vorhergehenden Ansprüche, d a d u r c h g e k e n n z e i c h n e t , daß das Faraday-Element (F) einen Stromleiter (50) , m dem der elektrische Strom (I) fließt, umgibt und insbesondere als Faserspule oder als massiver Glasring ausgebildet ist.8. Device according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that the Faraday element (F) surrounds a current conductor (50), m, which flows the electrical current (I), and is designed in particular as a fiber spool or as a solid glass ring.
9. Vorrichtung nach einem der vorhergehenden Ansprüche, d a d u r c h g e k e n n z e i c h n e t , daß dem9. Device according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that the
Faraday-Element (F) Mittel zur linearen Polarisation (12, 120) eines Sendelichtsignals (LS) vorgeschaltet smd.Faraday element (F) Means for linear polarization (12, 120) of a transmitted light signal (LS) upstream smd.
10. Vorrichtung nach Anspruch 9, d a d u r c h g e - k e n n z e i c h n e t , daß dem Faraday-Element (F)10. The device according to claim 9, d a d u r c h g e - k e n n z e i c h n e t that the Faraday element (F)
Mittel zur Umwandlung (121) einer im Faraday-Element (F) durch den elektrischen Strom (I) hervorgerufenen Beeinflussung eines Polarisationszustands m eine Intensitatsmodulation nachgeschaltet sind.Means for converting (121) an influencing of a polarization state m caused by the electrical current (I) in the Faraday element (F) are followed by an intensity modulation.
11. Vorrichtung nach einem der vorhergehenden Ansprüche, d a d u r c h g e k e n n z e i c h n e t , daß eine Breitbandlichtquelle (20) zur Emspeisung eines Sendelichtsignals (LS) m den Lichtpfad vorgesehen ist.11. Device according to one of the preceding claims, that a broadband light source (20) for supplying a transmitted light signal (LS) m is provided in the light path.
12. Vorrichtung nach einem der vorhergehenden Ansprüche, d a d u r c h g e k e n n z e i c h n e t , daß eine Auswerteeinheit (30) vorgesehen ist, in die der Lichtpfad ■ mündet und die insbesondere wellenlängenselektive Mittel, vorzugsweise ein optisches Filter oder ein Spektrometer, beinhaltet.12. Device according to one of the preceding claims, characterized in that a Evaluation unit (30) is provided, into which the light path ■ opens and which contains, in particular, wavelength-selective means, preferably an optical filter or a spectrometer.
13. Verfahren zur optischen Erfassung eines elektrischen Stroms (I) und mindestens einer Komponente (E^E^E eines elektrischen Felds, bei dem a) ein Sendelichtsignal (LS) erzeugt und in eine optische Reihenschaltung aus mindestens einem stromempfindlichen13. A method for the optical detection of an electric current (I) and at least one component (E ^ E ^ E of an electric field, in which a) generates a transmitted light signal (LS) and into an optical series circuit comprising at least one current-sensitive
Faraday-Element (F) und aus mindestens einem auf die mindestens eine Komponente (E^E^E des elektrischen Felds empfindlichen Element (Bι,Bj.,Bn) eingespeist wird, zumindest ein Anteil des Sendelichtsignals (LS) in sukzes- siver Abfolge b) durch das mindestens eine stromempfindliche Faraday- Element (F) in einem Polarisationszustand und c) durch das mindestens eine auf die mindestens eine Kom¬ ponente des elektrischen Felds empfindliche Element (B^B^B in einer von dem Polarisationszustand verschiedenen optischen Eigenschaft beeinflußt wird, und d) aus der Beeinflussung der von dem Polarisationszustand verschiedenen Eigenschaft mindestens eine erste Meßgröße (Mlι,Mli,Mln) für die mindestens eine Komponente (E E^E des elektrischen Felds und e) aus der Beeinflussung des Polarisationszustands eine zweite Meßgröße (M2) für den elektrischen Strom (I) abgeleitet wird.Faraday element (F) and from at least one element (Bι, Bj . , B n ) sensitive to the at least one component (E ^ E ^ E of the electric field), at least a portion of the transmitted light signal (LS) in successive sequence) b through the at least one Faraday current sensing element (F) in one polarization state and c) the at least one at least one component to the Kom ¬ of the electric field sensitive element (B ^ B ^ B is influenced in an optical property different from the polarization state, and d) from influencing the property different from the polarization state at least one first measured variable (Mlι, Mli, Ml n ) for the at least one Component (EE ^ E of the electric field and e) a second measured variable (M2) for the electric current (I) is derived from influencing the polarization state.
14. Verfahren nach Anspruch 13, d a d u r c h g e k e n n z e i c h n e t , daß das Sendelichtsignal (LS) durch das mindestens eine auf die mindestens eine Komponente des elektrischen Felds empfindliche Element in einem Wellenlangengehalt beeinflußt wird. 14. The method according to claim 13, characterized in that the transmitted light signal (LS) by the at least one sensitive to the at least one component of the electrical field element is affected in a wavelength content.
15. Verfahren nach Anspruch 14, d a d u r c h g e k e n n z e i c h n e t , daß das Sendelichtsignal (LS) durch em Bragg-Element (B^B^Bn) im Wellenlangengehalt beeinflußt wird.15. The method according to claim 14, d a d u r c h g e k e n n z e i c h n e t that the transmitted light signal (LS) is influenced by em Bragg element (B ^ B ^ Bn) in the wavelength content.
16. Verfahren nach Anspruch 15, d a d u r c h g e k e n n z e i c h n e t , daß em Piezokorper (Px) des Bragg-Elements durch die mindestens eine Komponente des elektrischen Felds m seiner Form und em mit dem Piezokorper (Pi) mechanisch verbundener zu- bzw. abführender Lichtwellenleiter (11, 13) des Faraday-Elements (F) seiner Lange verändert werden, wodurch das Sendelichtsignal (LS) m einem m den zu- bzw. abfuhrenden Lichtwellenleiter (11, 13) eingebrachtes Bragg-Gitter (Gx) vorbestimmter Bragg- Wellenlange (λi) im Wellenlangengehalt beeinflußt wird.16. The method according to claim 15, characterized in that em piezo body (P x ) of the Bragg element the length of the at least one component of the electric field m of its shape and em feeding and discharging optical waveguide (11, 13) of the Faraday element (F) mechanically connected to the piezo body (Pi) are changed, as a result of which the transmitted light signal (LS) m a Bragg grating (G x ) of predetermined Bragg wavelength (λi) introduced into and out of the optical waveguide (11, 13) is influenced in the wavelength content.
17. Verfahren nach einem der vorhergehenden Ansprüche, d a d u r c h g e k e n n z e i c h n e t , daß das Sendelichtsignal (LS) vor Eintritt m das Faraday-Element (F) linear polarisiert wird.17. The method according to any one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that the transmitted light signal (LS) before entering the Faraday element (F) is linearly polarized.
18. Verfahren nach einem der vorhergehenden Ansprüche, d a d u r c h g e k e n n z e i c h n e t , daß die im Faraday-Element (F) durch den elektrischen Strom (I) her- vorgerufene Beeinflussung des Polarisationszustands in eine Intensitatsmodulation überfuhrt wird.18. The method according to any one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that the influencing of the polarization state caused by the electrical current (I) in the Faraday element (F) is converted into an intensity modulation.
19. Verfahren nach einem der vorhergehenden Ansprüche, d a d u r c h g e k e n n z e i c h n e t , daß em breitbandiges Sendelichtsignal (LS) vorgesehen wird.19. The method according to any one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that a broadband transmission light signal (LS) is provided.
20. Verfahren nach Anspruch 14 bis 19, d a d u r c h g e k e n n z e i c h n e t , daß mindestens der m seinem Polarisationszustand und Wellenlangengehalt beeinflußte An- teil des Sendelichtsignals (LS) wellenlangenselektiv ausgewertet wird. 20. The method according to claim 14 to 19, characterized in that at least the portion of the transmitted light signal (LS) which is influenced by its polarization state and wavelength content is evaluated in a wavelength-selective manner.
21. Verfahren nach einem der vorhergehenden Ansprüche, d a d u r c h g e k e n n z e i c h n e t , daß aus der mindestens einen ersten Meßgröße (Ml^Ml^Ml für die mindestens eine Komponente (Eι,Ei,En) des elektrischen Felds eine dritte Meßgröße (M3) für eine elektrische Spannung (U) eines Stromleiters (50), in dem der elektrische Strom (I) fließt, abgeleitet wird. 21. The method according to any one of the preceding claims, characterized in that from the at least one first measured variable (Ml ^ Ml ^ Ml for the at least one component (Eι, Ei, E n ) of the electrical field, a third measured variable (M3) for an electrical voltage (U) of a current conductor (50) in which the electrical current (I) flows is derived.
EP99944241A 1998-07-16 1999-07-01 Device and method for optically detecting an electric current and a component of an electric field Withdrawn EP1145019A3 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19832056 1998-07-16
DE19832056 1998-07-16
PCT/DE1999/001967 WO2000004398A2 (en) 1998-07-16 1999-07-01 Device and method for optically detecting an electric current and a component of an electric field

Publications (2)

Publication Number Publication Date
EP1145019A2 true EP1145019A2 (en) 2001-10-17
EP1145019A3 EP1145019A3 (en) 2002-03-06

Family

ID=7874325

Family Applications (1)

Application Number Title Priority Date Filing Date
EP99944241A Withdrawn EP1145019A3 (en) 1998-07-16 1999-07-01 Device and method for optically detecting an electric current and a component of an electric field

Country Status (3)

Country Link
EP (1) EP1145019A3 (en)
AU (1) AU5726599A (en)
WO (1) WO2000004398A2 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2943426B1 (en) * 2009-03-20 2012-04-27 Thales Sa ELECTRO-OPTICAL ELECTROMAGNETIC FIELD MEASURING MEASUREMENT DEVICE
DE102012223089B4 (en) * 2012-12-13 2015-11-12 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Method and device for measuring electrical voltage
WO2017121489A1 (en) * 2016-01-15 2017-07-20 Siemens Aktiengesellschaft Arrangement and method for measuring integral field variables of current-carrying assemblies

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4216152A1 (en) * 1992-05-15 1993-11-18 Asea Brown Boveri Fiber optic sensor

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO0004398A3 *

Also Published As

Publication number Publication date
AU5726599A (en) 2000-02-07
WO2000004398A2 (en) 2000-01-27
EP1145019A3 (en) 2002-03-06
WO2000004398A3 (en) 2001-12-27

Similar Documents

Publication Publication Date Title
EP0011110B1 (en) Arrangement for electro-optical voltage measuring
EP0706662B1 (en) Optical method of measuring an alternating electrical current, including temperature compensation, and a device for carrying out the method
EP1154278B1 (en) Fibre-optic current sensor
EP0721589B1 (en) Method and device for measuring an alternating electrical quantity to include temperature compensation
EP1115000A2 (en) Fibre optic current sensor
WO1994024572A1 (en) Optical method of measuring an alternating electrical current, including temperature compensation, and a device for carrying out the method
EP0786091B1 (en) Process and device for measuring an alternating electric quantity with temperature compensation
EP0779988B1 (en) Process and device for measuring an alternating electric current with temperature compensation
EP0866974B1 (en) Optical measuring process and optical measuring arrangement for measuring an alternating quantity with intensity scaling
DE2924804A1 (en) Prevention of temperature effects on fibre optic polarisation - has detector sensing changes in light polarisation caused by variation in tensional stress due to temperature
DE3115804C2 (en)
EP0854354B1 (en) Method for temperature compensation of signals measured by a fiber optical sensor
EP0811170B1 (en) Process and device for measuring a magnetic field by faraday effect while compensating for intensity variations
DE60118662T2 (en) Arrangement for measuring the electric current through the Faraday effect
DE4129085A1 (en) OPTICAL SENSOR FOR ROTATIONAL MOVEMENTS
EP1284425B1 (en) Procedure and device for interference compensation of an optical sensor
EP1421393B1 (en) Optical current sensors
EP0529339B1 (en) Fibre optic sensor
EP1145019A2 (en) Device and method for optically detecting an electric current and a component of an electric field
EP1141663A1 (en) Fibre bragg grating sensors for measuring a physical magnitude
EP0864098B1 (en) Process and device for measuring a quantity, in particular an electric current, with a high measurement resolution
EP0786092B1 (en) Optical measuring process and device for measuring an electric a.c. voltage or an electric alternating field with temperature compensation
CH686744A5 (en) Fiberoptic current sensor.
DE10112835B4 (en) Method and device for current measurement by means of a fiber optic in-line Sagnac interferometer and suitable phase modulator
DE19902279A1 (en) Apparatus for measuring component of electrical field

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20001124

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

XX Miscellaneous (additional remarks)

Free format text: DERZEIT SIND DIE WIPO-PUBLIKATIONSDATEN A3 NICHT VERFUEGBAR.

PUAK Availability of information related to the publication of the international search report

Free format text: ORIGINAL CODE: 0009015

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20021127