WO2002004964A1 - Amperemetre d'interferometre de sagnac - Google Patents
Amperemetre d'interferometre de sagnac Download PDFInfo
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- WO2002004964A1 WO2002004964A1 PCT/JP2001/005853 JP0105853W WO0204964A1 WO 2002004964 A1 WO2002004964 A1 WO 2002004964A1 JP 0105853 W JP0105853 W JP 0105853W WO 0204964 A1 WO0204964 A1 WO 0204964A1
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- 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
- G01R15/245—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using light-modulating devices using magneto-optical modulators, e.g. based on the Faraday or Cotton-Mouton effect
- G01R15/246—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using light-modulating devices using magneto-optical modulators, e.g. based on the Faraday or Cotton-Mouton effect based on the Faraday, i.e. linear magneto-optic, effect
-
- 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
- G01R15/247—Details of the circuitry or construction of devices covered by G01R15/241 - G01R15/246
Definitions
- an optical fiber coil is arranged in a magnetic field generated by an electric current, and right-handed light and left-handed light are propagated through the optical fiber coil, and these two lights rotate in opposite directions due to the Faraday effect.
- the present invention relates to a Sanyak interferometer-type current sensor that measures the current by detecting the phase difference.
- a transformer consisting of an iron core and a winding coil is generally used to measure the current flowing through the power transmission and distribution lines. Since this transformer is a purely electrical device, it must meet the requirements for electrical noise resistance and electrical insulation resistance, and depending on where the transformer is installed, it is necessary to pay attention to its external dimensions. is there.
- the Sanyak interferometer composed of an optical fiber coil has been used as an optical fiber gyro for detecting the rotation of a moving body.
- current measurement can be performed by using this characteristic. That is, when a magnetic field is applied to an optical fiber coil, which is a transparent material, the polarization plane rotates due to the Faraday effect. The rotation angle of the polarization plane depends on the strength of the magnetic field and the distance that light passes through the magnetic field.
- light emitted from a light source 1 passes through a first optical splitter 2 used as an optical directional coupler, and further passes through a first polarizing filter 3 to a second optical splitter 4. Then, the light is split into two in the second optical splitter 4 and is incident on the current detection coil 6 as left-handed light and right-handed light.
- the light serving as the counterclockwise light is phase-modulated by the phase modulator 5, optically phase-modulated, passes through the first 1/4 wavelength plate 16, and enters one end of the current detection coil 6. Then, it circulates counterclockwise in the coil 6, exits from the coil 6, enters the second quarter-wave plate 17, and then sequentially passes through the second optical splitter 4 and the first polarizing filter 3.
- the light passes through and enters the first optical splitter 2, where it is branched and reaches the light receiver 7, where it is received.
- the light that becomes clockwise light from the second optical branching device 4 passes through the second 1Z4 wave plate 17 and is incident on the current detection coil 6, and circulates clockwise in the coil 6.
- the light sequentially passes through the first polarizing filter 3, enters the first optical splitter 2, is split by the light, reaches the light receiver 7, and is received therefrom.
- the first 14-wavelength plate 16 and the second 14-wavelength plate 17 convert the linearly polarized light incident through the polarizing filter 3 into circularly polarized light, and emit the circularly polarized light.
- the polarized light is emitted as linearly polarized light.
- a modulation signal is input from the oscillation circuit 9 to the phase modulator 5, and optical phase modulation is performed on clockwise light and counterclockwise light. Move the coil end when a magnetic field is applied to the current detection coil 6 close to the wire 10 so that the diameter direction is the extension direction of the wire 10, counterclockwise light and right after turning around the current detection coil 6.
- phase difference occurs between the surrounding lights, and the left-handed light and the right-handed light emitted from the current detection coil 6 combine and interfere with each other in the second optical branching device 4.
- the phase difference The phase-modulated light whose light intensity has changed correspondingly is received by the light receiver 7.
- the frequency of the intensity change of the interference light coincides with the frequency of the modulation signal from the oscillation circuit 9, and its phase corresponds to the phase difference between the left-handed light and the right-handed light.
- the phase-modulated light that has reached the light receiver 7 is converted into an electric signal whose amplitude changes according to the light intensity.
- the electric signal subjected to the photoelectric conversion is input to the synchronous detector 8.
- the modulated signal supplied to the phase modulator 5 from the oscillation circuit 9 is input to the synchronous detector 8 as a reference signal, and the input output of the photodetector 7 is synchronously detected.
- This synchronous detection output corresponds to the phase difference proportional to the magnetic field applied to the current detection coil 6.
- the current-sensing coil of the Sanyak interferometer-type current sensor enters and propagates left-handed light and right-handed light from both ends of the current detection coil, causing the two lights having a phase difference to interfere with each other and causing the interference light From the change in the light intensity, the value of the current that generates the magnetic field applied to the current detection coil is measured.
- the optical fiber shown by the thick line is constituted by a polarization maintaining optical fiber. That is, excluding the optical fiber constituting the current detection coil 6, an optical fiber of about 1 m length from the light source 1 to the first optical splitter 2, the first optical splitter 2 to the first polarization An optical fiber of about 1 m length to filter 3; an optical fiber of about lm from first polarization filter 3 to second optical splitter 4; and a phase modulator 5 to second optical splitter 4 Each optical fiber about 1 m long is composed of a polarization maintaining optical fiber.
- each of the optical fiber from the second optical splitter 4 to the first quarter-wave plate 16 and the optical fiber from the second optical splitter 4 to the second 14-wave plate '17 Assuming that the total length of the optical fiber constituting the current detection coil 6 is 10 m, the length is set to about 5 Om, and this 50 m optical fiber is composed of a polarization maintaining fiber. I have.
- the first optical splitter 2, the first polarizing filter 3, and the second optical splitter 4 are each also configured by a polarization maintaining optical fiber.
- Fig. 2 shows a Sanyak interferometer-type current sensor in which a length adjusting optical fiber coil is connected to the conventional example shown in Fig. 1.
- the detection coil in the Sanyak interferometer is formed by winding a single-mode optical fiber. When this coil is used as the current detection coil 6, its total length is 10%. A design winding of about m is sufficient to detect current.
- the Sanyak interferometer inserts the phase modulator 5 at one end of the detection coil 6 as described above. In general, alternating-current optical phase modulation is performed on left-handed light and right-handed light. If the optical fiber length of the detection coil 6 is about 10 m, it is difficult to obtain a sufficient modulation amplitude for the interference light between the left and right light because a sufficient propagation time difference between the left and right light cannot be obtained.
- an optical fiber coil 60 for length adjustment is connected in series to one end of the detection coil 6, and the detection coil 6 and the length adjustment are connected from one branch end of the second optical splitter 4.
- the length of the optical fiber including the optical fiber coil 60 for use and reaching the other branch end of the second optical branching device 4 is set to about 10 Om. That is, assuming that the optical fiber length of the detection coil 6 is 1 Om, the optical fiber length of the length adjusting optical fiber coil 60 is designed to be about 9 Om.
- the error of the modulation frequency with respect to the optimum driving frequency of the phase modulator 5 is proportional to the spike signal width, and this causes the bias fluctuation.
- the detection coil length L including the length adjusting optical fiber coil 60 and the modulation frequency f is designed to satisfy the following equation.
- the optical sensor that connects the optical elements and the optical fibers that connect between the optical elements is also indicated by a bold line in the Sanyak interferometer-type current sensor shown in FIG.
- the optical fiber coil 60 for adjusting the length of the optical fiber up to 90 m is also composed of a polarization maintaining optical fiber. As a result, the price of the entire Sanyak interferometer-type current sensor has become high.
- An object of the present invention is to provide a Sanyak interferometer-type current sensor that solves the above-mentioned problem based on the use of a polarization maintaining optical fiber.
- the emitted light is incident on the first polarizing filter through the optical directional coupler, and the linear light having a predetermined polarization plane emitted from the first polarizing filter is divided into two by the second optical splitter.
- One of which passes through the optical phase modulator further passes through the first 1/4 wavelength plate, and the other passes through the second 1/4 wavelength plate, and turns the current detection coil as left-handed light and right-handed light, respectively.
- a first deborizer is inserted between the optical directional coupler and the first polarizing filter.
- a second depolarizer and a second polarizing filter are inserted and connected between the optical phase modulator and the first quarter-wave plate, and the other end of the second optical splitter and the second splitter are connected to each other.
- a third depolarizer and a third polarizing filter are interposed between the two quarter-wave plates.
- a second deborrizer and a second polarizing filter are inserted and connected between the optical phase modulator and the first quarter-wave plate, and the other of the second optical splitters
- a third depolarizer and a third polarizing filter are inserted and connected between the branch end of the first and the second one- and four-wavelength plates, and a non-polarizing light source is used as a light source.
- a first length adjusting optical fiber coil is connected in series between one branch of the second optical splitter and the first 1/4 wavelength plate, and the second optical splitter is
- a second length-adjusting optical fiber coil is connected in series between the other branch end and the second 1Z4 wavelength plate, and the winding directions of the two length-adjusting optical fiber coils are mutually opposite. It is turned in the opposite direction, and its central axis is located on almost the same straight line.
- the central axes of the first and second length-adjusting optical fiber coils and the current detection coil are substantially on the same straight line, and the phase change of light due to the Sannyak effect applied to these three coils. Are mutually canceled.
- the space between the optical directional coupler and the second optical splitter is divided, and these are connected by the first optical connector, the extension optical fiber, and the second optical connector 22.
- the second splitter is divided between the first quarter-wave plate and the second quarter-wave plate, and these are divided into the first optical connector and two extended optical fibers—the second optical fiber. Preferably, they are connected by the optical connector 22.
- FIG. 1 is a diagram illustrating a conventional example.
- FIG. 2 is a diagram for explaining a conventional example in which a length adjusting optical fiber coil is connected.
- FIG. 3 is a diagram for explaining an embodiment of the present invention.
- FIG. 4 is a diagram for explaining the deborizer.
- FIG. 5 is a diagram for explaining another embodiment of the present invention.
- FIG. 6 is a diagram for explaining an embodiment of the present invention in which a length adjusting optical fiber coil is connected.
- FIG. 7 is a diagram illustrating an embodiment of the present invention divided into a plurality of blocks.
- FIG. 8 is a view for explaining another embodiment of the present invention divided into a plurality of blocks.
- the optical fiber for connecting the optical elements is constituted by a single mode optical fiber, and a devolatilizer for converting incident light into non-polarized light and emitting the light is used.
- the light emitted from the light source 1 is incident on the first debolizer 11 via the first optical splitter 2 as an optical directional coupler, and the transmitted light is converted into non-polarized light having the same amount of light between the orthogonal modes. .
- the non-polarized light emitted from the first deborizer 11 is incident on the first polarizing filter 3 and linearly polarized light within a predetermined polarization plane is selectively emitted.
- the linearly polarized light is converted into the second optical splitter 4. And is split into two, left-handed light and right-handed light.
- the branched left-handed light is optically phase-modulated in the phase modulator 5, and the left-handed light subjected to the optical phase modulation is incident on the second debolizer 12 and converted into non-polarized light.
- the light enters the polarization filter 14 and is converted into linearly polarized light within a certain predetermined polarization plane.
- the linearly polarized light emitted from the second polarizing filter 14 passes through the first quarter-wave plate 16 and is converted into circularly polarized light.
- This circularly polarized light is incident on one end of a current detection coil 6 composed of a single mode optical filter, circulates counterclockwise in the current detection coil 6, exits from the other end of the current detection coil 6, and is thus Z 4 wave plate 17
- the light passes through the three polarizing filters 15 in this order and is converted into linearly polarized light within a certain predetermined polarization plane.
- the linearly polarized light passes through the third deborrizer 13, is converted into non-polarized light, and is incident on the second optical splitter 4.
- the light that has passed through the second optical splitter 4 sequentially passes through the first polarizing filter 3 and the first deborrizer 11 to be unpolarized, and is incident on the first optical splitter 2.
- the light is received by the receiver 7.
- the right-handed light split by the second optical splitter 4 is incident on the third debolizer 13 and is converted into non-polarized light. It is converted to linearly polarized light in the plane of polarization.
- This linearly polarized light passes through the second 1/4 wavelength plate 17 and is converted into circularly polarized light.
- the circularly polarized light is incident on the current detection coil 6 and circulates clockwise in the current detection coil 6 to rotate the coil 6.
- the emitted light passes through the first quarter-wave plate 16 and the second polarizing filter 14 in order and is converted into linearly polarized light within a certain polarization plane.
- the light passes through the second debolizer 12 and is converted into non-polarized light.
- the non-polarized light is incident on the phase modulator 5 and is optically phase-modulated.
- the optical phase-modulated clockwise light passes through the second optical splitter 4 and further passes through the first polarizing filter 3 and the first deborizer 11 in order to be unpolarized.
- the light passes through the first optical splitter 2 and is received by the light receiver 7.
- the left-handed light and right-handed light that have passed through the current detection coil 6 combine and interfere in the second optical splitter 4, and as a result, the phase-modulated light whose light intensity has changed according to the phase difference between the two lights is received by the photodetector 7 Will be received.
- the interference phase modulated light that has reached the light receiver 7 is converted into an electric signal having an amplitude corresponding to the change in the light intensity.
- the electric signal from the photodetector 7 is synchronously detected by the synchronous detector 8 using the signal supplied from the oscillation circuit 9 as a reference signal, and corresponds to a phase difference proportional to the magnetic field applied to the current detection coil 6. A detection output is obtained.
- Unpolarized light is light that satisfies the condition that the light quantity between the orthogonal modes is equal and the light between the orthogonal modes is incoherent.
- Light that satisfies this condition can be obtained by passing through a deborizer.
- the deborizer is configured by joining a polarization maintaining optical fiber 21 having a length L 1 and a polarization maintaining optical fiber 22 having a length L 2 at one end face thereof.
- the ratio between L 1 and L 2 is 1: 2
- the two polarization-maintaining optical fibers 21 and 22 are fused to each other with their natural axes x and y shifted by 45 °.
- the deborrizer configured here is called a Rio type deborizer, and the unit length Lu of this Rio type deborrizer is usually determined by light propagating through two eigen axes X and y of the polarization maintaining optical fiber. It is the length that sets the group delay time difference between the generated orthogonal components to be equal to or longer than the coherent time of light (for details, see Journal of Lightwave Technology Vol. LTl Nol Mar 1983, pp. 71-74).
- the lengths L 1 and L 2 of the polarization maintaining optical fibers have a ratio.
- the group delay time difference between the quadrature components generated by the first, second, and third debolizers 11, 12, and 13 is larger than the coherent time of light.
- the ratio of the group delay time difference between the orthogonal components generated by each of the second deborizer 12 and the third deborizer 13 is, for example, 1: 2: 4. In this case, the beat length of each polarization maintaining optical fiber is assumed to be equal.
- One deborrizer causes the group delay difference between the eigen axes X and y to be equal to or longer than the coherent time of the light, but the polarization plane rotates while the unpolarized light propagates through the single-mode optical fiber,
- the component of the eigenaxis y was delayed in the previous deborizer, but the component may be incident as the X component in the next devolarizer, and in such a case, the light passing through the deborizer
- the group delay time difference between orthogonal components becomes less than the coherent time of light, and the condition of non-polarization is not satisfied.
- the group delay time difference of the next deborizer is twice as large as that of the first debolizer, the group delay time difference between the orthogonal components of the light when passing through this deborizer is always the coherent time of the light. As described above, the light is unpolarized. From the configuration shown in Fig. 1, the ratio of the group delay time difference that occurs in each of the debolalizers 1 1, 1 2, and 13 may be 4: 1: 2, and is larger than the 1: 2: 4 ratio difference regardless of the order. Obviously there is no problem.
- 1st Deborizer 11 Unit length of Rio-type deborizer 2 Ocm (ratio 1)
- the beat length of a normal polarization maintaining optical fiber is about 2 mm, and the coherent time of the used light is 1.6.
- X 1 ⁇ 1 3 seconds to
- the group delay time difference between orthogonal components while propagating the polarization maintaining file I bar length 2 0 cm becomes 2. 7 x 1 0 1 3 sec, this This is longer than the coherent time, which is the coherent time of the superluminescent diode light source generally used in fiber optic gyros.
- the unit length is 4 O cm (ratio 2), and the unit length of the lyo-type deborizer used for the third deborizer 13 is 8 O cm (ratio 4).
- the first, second, and third debolizers 11, 12, and 13 are composed of polarization-maintaining optical fibers, and the group delay between orthogonal components caused by the polarization-maintaining optical fiber.
- the time difference is larger than the coherent time of the light
- the ratio of the group delay time difference between the orthogonal components generated by the first deborizer 11, the second deborizer 12, and the third deborizer 13 is 1: 2: 4 or 1 : 4: 2 or more than these ratios
- the left and right bi-directional light propagates through the optical path without polarization, respectively, and the left and right bi-directional light are combined. It is possible to suppress a zero drift error.
- the optical fibers connecting the optical elements are all constituted by single-mode optical fibers, the polarization of single-mode light is not guaranteed to preserve the polarization plane.
- the polarization plane changes slightly during propagation through the fiber.
- the optical fiber connecting the light source 1 and the first optical splitter 2 is composed of an inexpensive single-mode optical fiber
- the first optical splitter 2 is composed of an inexpensive single-mode optical fiber.
- Polarized light is obtained.
- Light can be incident on the first polarizing filter 3 to obtain appropriate linearly polarized light.
- the linearly polarized light emitted from the first polarizing filter 3 is converted into a long single-mode light from the second optical splitter 4 to the second debolalizers 12 and 13 respectively.
- the pair of the second deborrizer 12 and the second polarization filter 14 and the second The depolarizer 13 and the third polarizing filter 15 return the linearly polarized light within the predetermined polarization plane.
- These linearly polarized light passes through the 1Z4 wave plates 16 and 17 and the current detection coil 6 Is incident as necessary circularly polarized light.
- left-handed light and right-handed light emitted around the current detection coil 6 are output from the second quarter-wave plate 17 and the third polarizing filter 15, respectively, and the first The four-wavelength plate 16 and the second polarizing filter 14 convert the polarized light into linearly polarized light having a predetermined polarization plane while maintaining the phase difference based on the passage of the current detection coil 6, and these linearly polarized lights are respectively converted to the third polarized light.
- Depolarizer 13 and second deborizer 12 convert the light into non-polarized light while maintaining their respective phase differences, respectively, through a single-mode optical fiber, and undergo full-wave interference in second optical splitter 4, and Interfering light whose intensity varies according to the phase difference is converted into linearly polarized light having a predetermined polarization plane by the first polarizing filter 3, and the interference light is maintained in a state where the intensity change is maintained by the first deborrizer 11. Polarized and this unpolarized The interference light enters the light receiver 7 through the first optical splitter 2 composed of a single-mode optical fiber, and is converted into an electric signal whose amplitude changes in accordance with the change in the light intensity. It is detected simultaneously.
- the first debolizer 11 is located between the first optical splitter 2 and the first polarizing filter 3.
- the somewhat changed polarization plane can be returned to the specified polarization plane, thereby achieving proper operation and overall operation.
- an inexpensive sanyak interferometer-type current sensor can be constructed.
- the optical fiber connecting the light source 1 and the first optical splitter 2 is composed of an inexpensive single-mode optical fiber
- the first optical splitter 2 is composed of an inexpensive single-mode optical fiber.
- the pair of the second debolizer 12 and the second polarizing filter 14 and the pair of the third debolizer 13 and the third polarizing filter 15 are not provided.
- Each optical element and optical fiber from the optical splitter 4 to the first 14-wave plate 16 and the second 1 / 4-wave plate 17 are polarized similarly to the conventional example shown in FIG. It consists of a maintenance optical fiber.
- the light is not guaranteed to preserve its polarization plane from the light source 1 to the first deborrizer 11, but the first light splitter 2 and the first polarizing filter 3
- the depolarizer 11 of this type non-polarized light is obtained, and this non-polarized light is made incident on the first polarizing filter 3, and then the first quarter-wave plate 16,
- An appropriate linearly polarized light can be made incident on the 1/4 wavelength plate 16 of FIG.
- the natural axis of the light from the light source 1 matches the natural axis of the polarization maintaining optical fiber. It is very convenient because troublesome adjustment is not required.
- the first deborizer 11 is removed, and a light source that generates non-polarized light such as an LED is used as the light source 1.
- the optical fiber operates properly, does not require the alignment of the light source 1 with the optical fiber, and can use a single-mode optical fiber as an optical fiber, so that it can be configured at low cost.
- the other may be set to 2 or more.
- a length adjusting optical fiber coil may be provided as shown in FIG.
- the former uses a single-mode optical fiber
- the latter uses a polarization-maintaining optical fiber to form a length adjusting optical fiber.
- FIG. 6 parts corresponding to those in FIG. 3 are given the same reference numerals.
- the optical fiber path between one branch end of the second optical splitter 4 and the first 1/4 wavelength plate 16 is called a first optical path, and the other of the second optical splitter 4 is called the first optical path.
- the path of the optical fiber between the branch end and the second 1/4 wavelength plate 17 is referred to as a second optical path.
- a counterclockwise length adjusting optical fiber coil 71 is inserted in series in the first optical path
- a clockwise length adjusting optical fiber coil 72 is inserted in series in the second optical path. .
- the length adjustment coil is divided and inserted into both optical paths, and the counterclockwise length adjustment optical fiber coil 71 and clockwise length adjustment optical fiber coil 72 are single-mode optical fibers, respectively. It is configured as a coil.
- the rotation of the optical fiber coil causes a Sanyak effect, and the phase of light propagating through the length adjusting optical fibers 71 and 72 changes.
- the Sanyak effect that occurs in these length-adjusting optical fiber coils 71 and 7.2 does not affect the phase difference between left-handed light and right-handed light generated by the Faraday effect due to the original magnetic field of the current detection coil 6. It is necessary to adopt a configuration.
- the winding directions of the left-handed length adjusting optical fiber coil 71 and the right-handed length adjusting optical fiber coil 72 are opposite to each other, and the center axes of the two optical fiber coils 71 and 72 are opposite to each other. Are positioned on substantially the same straight line.
- the sanitary effect of the left-handed length adjusting optical fiber coil 71 and the right-handed length adjusting optical fiber coil 72 cancel each other.
- the conventional current sensor shown in FIG. 1 when the current detection coil 6 rotates from its central axis, a phase difference is generated between the left-handed and right-handed light due to the Sagnac effect. This results in a current detection error.
- the phase difference due to the Sannyak effect in the current detection coil 6, the optical fiber coil 71 for adjusting the counterclockwise length, and the optical fiber coil 72 for adjusting the clockwise length is totally different. What is necessary is just to make it small.
- the center axes of the coils 6, 71 and 72 are positioned in almost the same direction, and by satisfying the following conditions, the current detection coil 6, optical fiber coil 71 and optical fiber coil In step 72, the phase difference due to the Saniyak effect caused by each rotation can be made smaller as a whole.
- Average radius of Rc current detection coil (example: 0.5 m)
- Fiber length of current detection coil (Example: 10 m)
- Average radius of optical fiber coil for counterclockwise length adjustment 71 (Example: 0.035 m
- L 2 clockwise length adjusting optical fiber coil 7 2 of the optical fiber length (Example: 2 0 0 m)
- optical fiber length 2 6 7 m
- the cutoff wavelength of each single mode optical fiber in the first optical path and the second optical path is 100 nm or more longer than the light source wavelength on the long wavelength side. It is good to shift. This is done as follows.
- Light source 1 A semiconductor light source with a wavelength of 0.83 i / m band is used. This light source is widely used as a light source for compact disc players.
- Optical fiber A single mode optical fiber for 1.3 ⁇ m wavelength is adopted.
- the cut-off wavelength of this single-mode optical fiber is about 1.2 ⁇ m, and is widely used in optical communications.
- the higher-order mode normally propagates, but as shown in the figure, the first optical path has a left
- the optical fiber coil 71 for adjusting the rotation length is connected to the second optical path
- the optical fiber coil 72 for adjusting the clockwise length is connected to the second optical path.
- the first deborizer 11, the second deborizer 12, and the second polarization makes it possible to operate well as a current sensor.
- the Sanyak interferometer-type current sensor when detecting the magnetic field generated by the current flowing through the electric wire, it is necessary to arrange the entire current sensor including the current detection coil 6 close to the electric wire. There were many inconveniences and difficulties in maintenance. Therefore, a configuration is adopted in which the Sanyak interferometer-type current sensor is mechanically divided into a plurality of blocks between the optical elements constituting the current sensor, and the divided blocks are connected via an optical connector and an optical fiber. .
- FIG. 7 shows an embodiment of a current sensor of a Sanyak interferometer type divided into a plurality of blocks between optical elements, and members common to those of the embodiment shown in FIG. 3 are denoted by common reference numerals.
- the first optical splitter 2 and the second optical splitter 4 are divided, and the two blocks of the light source side block B and the current detection coil side block C are divided into the second block.
- the first optical connector 21, the second optical connector 22, the first optical connector 21 and the second optical connector 22 are connected by an extended optical fiber 20.
- the extension optical fiber 20 is made of a single-mode optical fiber
- the first optical connector 21 and the second optical connector 22 are made of single-mode optical fiber connecting optical connectors.
- FIG. 7 shows the division between the first optical splitter 2 and the first debolizer 11, and this division point is divided into the first polarization filter 3 and the second light It can also be set to the branch 4.
- the optical splitter is divided into a light source side block B and a current detection coil side block C.
- the current detection coil side block C can be separately installed near the high voltage electric wire, and the entire current sensor is installed near the high voltage electric wire.
- the extended optical fiber 20 connecting between the first optical connector 21 and the second optical connector 22 can be a single-mode optical fiber, and the first optical connector 21 And the second optical connector 22 also connect the single mode optical fiber
- An optical connector for connecting a single mode optical fiber can be provided. If the optical fiber that connects the optical elements is a polarization maintaining optical fiber, the optical connector will naturally be an optical connector for connecting the polarization maintaining optical fiber. The price of an optical connector for connecting an optical fiber is significantly higher than that of an optical connector for connecting a single mode optical fiber. In the case of this embodiment, the blocks can be connected to each other by an inexpensive single mode optical fiber connection optical connector.
- the embodiment shown in FIG. 8 divides the second optical splitter 4 and the first 14-wavelength plate 16 and the second Connect the block B and the block C of the current detection coil side block C to the first optical connector 21, the second optical connector 22, the first optical connector 21, and the second optical connector 22. Connect between two extended optical fibers 20.
- the configuration of the current detection coil side block C is further simplified as compared with the case of the previous embodiment, and various difficult conditions concerning installation and maintenance can be eased.
- Each of the first optical connector 21 and the second optical connector 22 is a two-core connector, and the connection work between the blocks B and C can be simplified by the two extended optical fibers 21.
- the current was measured in an open loop, but the current can be measured in a closed loop as in the case of the closed-loop optical fiber jar opening, and in this case, the present invention can be applied.
- the second optical splitter 4 and any one of the optical paths between the first 1Z 4 wavelength plate 16 and the second 1/4 wavelength plate 17 The optical phase modulator is inserted, and the output of the detection circuit 8 is used to perform optical phase modulation so that the phase difference between the left-handed light and the right-handed light is reduced, and when the phase difference becomes almost zero.
- the amplitude of the modulation signal of the second optical phase modulator corresponds to the detected current.
- the phase difference between the left and right surrounding light generated in the current detection coil due to the influence of the magnetic field is detected by using the Sanyak type interferometer, and both ends of the current detection coil are detected.
- the nonreciprocal phase difference generated by the magnetic field is maximized to optimize the sensitivity to the magnetic field, that is, the current.
- the measurement range can easily realize a measurement range of 4 digits or more based on the results of the optical fiber mouth.
- a sanyak interferometer-type current sensor can be configured.
- a length adjusting optical fiber coil is provided on the first optical path of the optical fiber between one branch of the second optical splitter and the first quarter-wave plate.
- the length adjustment optical fiber coil is connected in series to the second optical path of the optical fiber between the other branch of the second optical splitter and the second quarter-wave plate,
- the optical fiber length of the length adjusting optical fiber coil is designed to be about 9 Om, which is extremely long, the cost reduction effect by using an inexpensive single-mode optical fiber is significant.
- the optical paths connecting the optical elements are all composed of inexpensive single-mode optical fibers, and if a deborrizer, a polarizing filter and a 14-wave plate are provided at both ends of the current detection coil 6, the By returning the changed polarization plane to the predetermined polarization plane, it is possible to configure an inexpensive sannyak interferometer-type current sensor that operates properly and is inexpensive as a whole.
- the optical fiber connecting the light source 1 and the first optical splitter 2 is constituted by an inexpensive single-mode optical fiber
- the first optical splitter 2 is constituted by an inexpensive single-mode optical fiber.
- the light preserves the polarization plane from the light source 1 to the first deborizer 11
- this unpolarized light is converted to the first polarized light filter.
- the light can enter the first 14-wave plate 16 and the second 1 / 4-wave plate 17 as appropriate linearly polarized light.
- the counterclockwise length adjusting optical fiber coil 71 and the clockwise length adjusting optical fiber coil 72 are opposite to each other, the counterclockwise length adjusting optical fiber coil 71 And the optical fiber coil 72 for clockwise length adjustment can cancel each other out of the Sannyak effect.
- the three members of the current detection coil 6, the left-handed length adjusting optical fiber coil 71, and the right-handed length adjusting optical fiber coil 72 have a mutual relationship with respect to the phase difference due to the Saniyak effect.
- the first optical path has a counterclockwise length-adjusting optical fiber coil.
- the second optical path is connected to the clockwise length adjusting optical fiber coil 72, the higher-order modes are easily leaked and propagated due to the bending effect of these coils. There is no.
- inexpensive general-purpose products can be used.
- the light source side block B and the current detection coil side block C can be installed on the ground near the high voltage tower, and the current detection coil side block C can be separately installed near the high voltage electric wire. In comparison, various difficult conditions related to installation and maintenance can be reduced. The fact that the above-described division can be performed can also be attributed to the effect of connecting the optical elements with a single-mode optical fiber. Further, the second optical splitter 4 and the first 1Z4 wavelength plate 16 and the second 1/4 wavelength plate 17 are divided into two blocks, a divided light source side block B and a current detection coil side block C.
- the first optical connector 21, the second optical connector 22, and the first optical connector 21 and the second optical connector 22 are connected to each other by the extended optical fiber 20.
- the configuration of the current detection coil side block c is further simplified in cylinder, and various difficult conditions relating to installation and maintenance can be reduced. '
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
- Gyroscopes (AREA)
- Measurement Of Current Or Voltage (AREA)
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/070,076 US6831749B2 (en) | 2000-07-07 | 2001-07-05 | Sagnac interferometer current sensor |
EP01947859A EP1302774B1 (en) | 2000-07-07 | 2001-07-05 | Sagnac interferometer current sensor |
DE60123066T DE60123066T8 (de) | 2000-07-07 | 2001-07-05 | Sagnac-interferometer-stromsensor |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2000206197A JP4234885B2 (ja) | 2000-07-07 | 2000-07-07 | サニヤック干渉計型電流センサ |
JP2000-206197 | 2000-07-07 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2002004964A1 true WO2002004964A1 (fr) | 2002-01-17 |
Family
ID=18703157
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2001/005853 WO2002004964A1 (fr) | 2000-07-07 | 2001-07-05 | Amperemetre d'interferometre de sagnac |
Country Status (6)
Country | Link |
---|---|
US (1) | US6831749B2 (ja) |
EP (1) | EP1302774B1 (ja) |
JP (1) | JP4234885B2 (ja) |
CN (1) | CN1182401C (ja) |
DE (1) | DE60123066T8 (ja) |
WO (1) | WO2002004964A1 (ja) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2006050887A1 (en) | 2004-11-09 | 2006-05-18 | Novartis Ag | Process for the preparation of enantiomers of amidoacetonitrile compounds from their racemates |
Families Citing this family (20)
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JP3533651B1 (ja) * | 2002-09-20 | 2004-05-31 | 独立行政法人 科学技術振興機構 | 時間分解・非線形複素感受率測定装置 |
JP2004301769A (ja) * | 2003-03-31 | 2004-10-28 | Toshiba Corp | 光電流計測器およびそれを用いた電流差動保護システム |
JP4404717B2 (ja) * | 2004-08-02 | 2010-01-27 | 株式会社高岳製作所 | 光電流センサ |
TWI278638B (en) * | 2005-09-20 | 2007-04-11 | Hermann Lin | Fiber-optics multiplexed interferometric current sensor |
US20100309473A1 (en) * | 2007-12-21 | 2010-12-09 | Honeywell International Inc. | Fiber optic current sensor and method for sensing current using the same |
JP2009222725A (ja) * | 2009-07-06 | 2009-10-01 | Toshiba Corp | 光電流検出装置 |
JP5904694B2 (ja) * | 2009-12-10 | 2016-04-20 | 株式会社東芝 | サニャック干渉型光電流センサ |
CA2783295C (en) * | 2009-12-11 | 2017-03-28 | William Verbanets | Magneto optical current transducer with improved outage performance |
CN102128967B (zh) * | 2010-12-15 | 2013-02-27 | 北京航空航天大学 | 三相共用超荧光光纤光源的光纤电流互感器 |
JP5626005B2 (ja) * | 2011-02-24 | 2014-11-19 | 日立金属株式会社 | 光学的成分測定装置 |
CN103207301A (zh) * | 2012-01-16 | 2013-07-17 | 中国科学院西安光学精密机械研究所 | 一种光纤电流传感器线圈及基于该线圈的光纤电流传感器 |
EP2682765A1 (en) * | 2012-07-05 | 2014-01-08 | ABB Research Ltd. | Temperature compensated fiber-optic current sensor |
WO2015033001A1 (es) * | 2013-09-04 | 2015-03-12 | Arteche Centro De Tecnología, A.I.E. | Sistema óptico para la identificación de faltas en líneas mixtas de transporte eléctrico |
CN103954827A (zh) * | 2014-04-03 | 2014-07-30 | 易能乾元(北京)电力科技有限公司 | 一种光学电流传感器 |
CN103969501B (zh) * | 2014-05-15 | 2016-10-05 | 北京航佳科技有限公司 | 一种光学电流传感器 |
CN104964681B (zh) * | 2015-07-16 | 2017-10-13 | 陕西华燕航空仪表有限公司 | 一种开环光纤陀螺的自检电路及自检方法 |
CN109633241B (zh) * | 2018-12-30 | 2020-10-23 | 广州申畅沃光电科技有限公司 | 一种便携式柔性光纤电流测量分析仪 |
US11036008B2 (en) | 2019-02-27 | 2021-06-15 | General Electric Technology Gmbh | Employing depolarizer arrangements to mitigate interference in an optical link due to vibration and current effects |
CN110108960A (zh) * | 2019-05-16 | 2019-08-09 | 国家电网有限公司 | 一种便携式光纤用户电能质量检测分析装置 |
EP3901638A1 (en) * | 2020-04-21 | 2021-10-27 | General Electric Technology GmbH | Employing depolarizer arrangements to mitigate interference in an optical link due to vibration and current effects |
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2000
- 2000-07-07 JP JP2000206197A patent/JP4234885B2/ja not_active Expired - Fee Related
-
2001
- 2001-07-05 CN CNB018019471A patent/CN1182401C/zh not_active Expired - Fee Related
- 2001-07-05 WO PCT/JP2001/005853 patent/WO2002004964A1/ja active IP Right Grant
- 2001-07-05 US US10/070,076 patent/US6831749B2/en not_active Expired - Fee Related
- 2001-07-05 EP EP01947859A patent/EP1302774B1/en not_active Expired - Lifetime
- 2001-07-05 DE DE60123066T patent/DE60123066T8/de active Active
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JPH06347275A (ja) * | 1993-06-08 | 1994-12-20 | Japan Aviation Electron Ind Ltd | 光ファイバジャイロ |
JPH07191061A (ja) * | 1993-12-27 | 1995-07-28 | Toshiba Corp | 光応用センサ |
JPH07198398A (ja) * | 1994-01-06 | 1995-08-01 | Sumitomo Electric Ind Ltd | 光ファイバジャイロ、位相変調器及びその製造方法 |
JPH11316247A (ja) * | 1998-05-01 | 1999-11-16 | Hitachi Ltd | 電流測定方法及び光電流センサ |
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2006050887A1 (en) | 2004-11-09 | 2006-05-18 | Novartis Ag | Process for the preparation of enantiomers of amidoacetonitrile compounds from their racemates |
Also Published As
Publication number | Publication date |
---|---|
JP4234885B2 (ja) | 2009-03-04 |
DE60123066T2 (de) | 2007-02-08 |
US20020122183A1 (en) | 2002-09-05 |
US6831749B2 (en) | 2004-12-14 |
EP1302774A4 (en) | 2005-06-29 |
EP1302774B1 (en) | 2006-09-13 |
DE60123066T8 (de) | 2007-06-06 |
DE60123066D1 (de) | 2006-10-26 |
CN1182401C (zh) | 2004-12-29 |
JP2002022776A (ja) | 2002-01-23 |
CN1386199A (zh) | 2002-12-18 |
EP1302774A1 (en) | 2003-04-16 |
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