JP2001356137A - Optically applied measuring device and protective control device using the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a measurement with high precision and excellent stability. SOLUTION: In this optically applied measuring device, a physical quantity is measured from the change of polarizing characteristic of an optical element by use of that the polarizing characteristic of the optical element is changed by a change of physical quantity. As a light source to be used for the measurement, a light source emitting a random polarized light is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an applied optical measuring device for measuring a change in a physical quantity by utilizing a change in the polarization characteristic of an optical element, and more particularly to an applied optical measuring device for measuring a current or a voltage and using this device. The present invention relates to a protection control device for power equipment.

[0002]

2. Description of the Related Art Conventionally, as a protection device used for power equipment such as a substation or a transmission line, for example, as shown in FIG. 14, an iron core type current transformer is provided at both ends of a bus or a transmission line 54 in a section to be protected. The current signals I1 and I2 measured by the current transformers 55 and 56 are input to the differential relay 53, and in response to the vector difference of the current flowing through both ends of the bus or the transmission line 54. The section is protected.

In such a protection device, if there is no accident in the protection section, the current value input to the differential relay 53 is the same, and the current vector difference is zero, so that the differential relay 53 does not operate. In the event of a ground fault, a difference occurs in the value of current flowing between both ends, so that the differential relay 53 detects the current vector difference and performs a protection operation.

Accordingly, in the current transformers 55 and 56 used in such a protection device for electric power equipment, the characteristics of the current transformers are relatively more consistent than the magnitude of the absolute value of the measured current. It is necessary.

[0005]

However, the above-described protection device for power equipment has the following problems.

That is, an iron core type current transformer has a large error due to magnetic saturation in a large current range, which causes a malfunction of the differential relay. To avoid this, the detection sensitivity of the differential relay may be reduced. However, this cannot realize a high-sensitivity protection device.

Therefore, as a means for avoiding the influence of the magnetic saturation of the current transformer, a current measuring device using an optical current transformer has recently attracted attention.

FIG. 13 shows a schematic configuration of a current measuring device using such an optical current transformer.

As shown in FIG. 13, a He-Ne laser beam output from a laser light source 38 is linearly polarized by a polarizer 5, and is incident on a single mode fiber 41 through an objective lens 39. This single mode fiber 41
Causes the light passing through the single mode fiber 41 to undergo Faraday rotation due to a magnetic field generated by the bus current.

The light exiting the single mode fiber 41 is converted into parallel light by an objective lens 39 and enters a Wollaston prism 42. This Wollaston prism 42 is 45 ° with respect to the incident polarization direction when the Faraday rotation is 0.
, And the light emitted from the fiber is defined as a two-component light intensity signal that is orthogonal.

The light is photoelectrically converted by the detector 11, and the electronic circuit 12 performs necessary calculations, and then outputs the current as a current value.

Here, assuming that the signals photoelectrically converted by the detector 11 are I1 and I2, (I1-I2) / (I1 + I
By performing the calculation of 2), regardless of the incident intensity,
The Faraday rotation angle can be determined.

The current measuring device using such an optical fiber has a high insulation property, has no saturation in principle, and can perform highly linear measurement up to a large current range. However, the sensitivity of an optical current transformer depends on the wavelength of the light source.However, even if a laser diode of the same model is used due to manufacturing variations, the laser diode conventionally used as the most reliable light source is not Since there is a large variation in the oscillation wavelength and the oscillation spectrum shape, the actual situation is that the electronic circuit side corrects and uses these.

Further, even if a laser diode having the same characteristics can be obtained, its oscillation wavelength and spectrum shape have temperature dependence, so that temperature stabilization of the laser diode is indispensable, and its stability is measured by current measurement. Had limited accuracy. Further, the laser diode has a phenomenon called mode hopping in which the oscillation output intensity changes suddenly when the oscillation wavelength changes, and an error due to this mode hopping is also a factor that limits the accuracy of current measurement.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. An optical measuring apparatus and a light measuring apparatus which are small in size, high in accuracy, and capable of stably measuring a temperature change are provided. The purpose is to provide a protection control device used

[0016]

In order to achieve the above object, the present invention constitutes an optical measuring device and a protection control device using the same by the following means.

The invention corresponding to claim 1 utilizes the fact that the polarization characteristic of an optical element changes due to a change in a physical quantity, and is used for measurement in an optical applied measurement device that measures a physical quantity from a change in the polarization property of an optical element. It is characterized in that a light source emitting random polarized light is used as the light source.

According to the optical measuring apparatus having such a configuration, the amount of light transmitted through the polarizer can be stabilized.

According to a second aspect of the present invention, in the optical applied measuring apparatus according to the first aspect, the light source is a fiber.

If the light source is a fiber as described above, a random light source that can be easily coupled to the sensor fiber can be realized.

According to a third aspect of the present invention, in the optical application measuring apparatus according to the first aspect, the light source is a rod-type solid-state laser.

As described above, if the light source is a rod-type solid laser, a random light source that can be easily coupled to a sensor fiber can be realized.

The invention corresponding to claim 4 utilizes the fact that the polarization characteristic of an optical element changes due to a change in a physical quantity, and is used for measurement in an optical applied measurement apparatus that measures a physical quantity from a change in the polarization property of an optical element. As a light source, a light source that emits two orthogonally polarized waves is used.

According to the optical measuring apparatus having such a configuration, the amount of light transmitted through the polarizer can be stabilized.

According to a fifth aspect of the present invention, in the optical applied measuring apparatus according to the fourth aspect, the light source for emitting the two orthogonal polarizations has a laser diode and a birefringent axis in the polarization direction of the laser diode. It is characterized in that the polarization-maintaining fiber, the two sets of laser diodes, and the polarization-maintaining fiber that are installed together are constituted by a polarization-maintaining fiber coupler connected so that the output polarization directions of the birefringent fiber are orthogonal. .

According to the optical measuring apparatus having such a configuration, it is possible to easily obtain a small and highly reliable orthogonal dual frequency light source.

According to a sixth aspect of the present invention, in the optical applied measuring apparatus according to the fifth aspect, a fiber diffraction grating is used for a resonator of a laser diode as a light source.

According to the optical measuring apparatus having such a configuration, the oscillation wavelengths of the two laser diodes can be made close to each other, and errors due to the oscillation wavelengths can be reduced.

The invention corresponding to claim 7 utilizes the fact that the polarization characteristic of an optical element changes due to a change in a physical quantity, and is used for measurement in an optical applied measurement apparatus that measures a physical quantity from a change in the polarization characteristic of an optical element. It is characterized in that a temperature-controlled SLD is used as a light source, and the output of the light source is depolarized by a depolarizing element.

According to the optical measuring apparatus having such a configuration, the oscillation spectrum shape and the amount of light after passing through the polarizer can be stabilized, and the accuracy of the measuring apparatus can be improved.

The invention corresponding to claim 8 utilizes the fact that the polarization characteristic of an optical element changes due to a change in a physical quantity, and is used for measurement in an optical applied measurement apparatus that measures a physical quantity from a change in the polarization characteristic of an optical element. A laser diode whose temperature is controlled is used as a light source, and the output of the light source is depolarized by a depolarizing element.

According to the optical measuring device having such a configuration, the oscillation spectrum shape and the amount of light after passing through the polarizer can be stabilized, and the accuracy of the measuring device can be improved.

According to a ninth aspect of the present invention, in the optical applied measuring apparatus according to the eighth aspect, the laser diode is operated by adding an AC component to a drive current.

According to the optical measuring apparatus having such a configuration, the coherence length of the laser diode is shortened, and the function of enhancing the polarization phase effect by the depolarizing element is achieved. In the optical applied measurement device according to the invention corresponding to 9, the frequency of the AC component is 10
MHz or more.

According to the optical measuring apparatus having such a configuration, the coherence length becomes 15 m or less, and the polarization can be effectively eliminated.

According to an eleventh aspect of the present invention, there is provided a protection control device for performing protection or control operation based on a difference signal of measurement signals measured by a plurality of optical applied measuring devices. Is characterized in that light from one light source is branched and used.

According to the protection control device having such a configuration,
A measuring device with uniform characteristics can be realized, and highly sensitive protection control can be realized.

The invention corresponding to claim 12 is the invention according to claim 11
In the protection control device according to the invention, the optical applied measuring device is a current or voltage measuring device for measuring polyphase alternating current, and the same light source is used for the optical applied measuring device for measuring each phase voltage or current. It is characterized by having been.

According to the protection control device having such a configuration,
Since the same light source is used for the current or the voltage at a plurality of locations, the 0-phase voltage can be accurately detected. This means that the zero-phase voltage or current is usually 0 even when the zero-phase voltage or current is not included as the measurement target.
Therefore, it can be used as a monitoring function for inspecting an error of the optical applied measurement device.

The invention corresponding to claim 13 is the invention according to claim 11
In the protection control device according to the invention, the sum of the currents flowing in and out of the protection section is obtained by using the optical applied measurement device as a current measurement device, and the protection operation is performed based on the sum of the currents.

According to the protection control device having such a configuration, a large number of the same current measuring devices are arranged, and a current measuring device with completely uniform characteristics can be realized. Can be.

According to a fourteenth aspect of the present invention, there is provided a protection control device for performing protection or control operation based on a ratio of measurement signals measured by a plurality of optical applied measuring devices, It is characterized in that light from one light source is branched and used.

According to the protection control device having such a configuration,
Since errors in a plurality of optical applied measurement devices caused by the light source occur in the same direction, the signal ratio can be accurately taken out, and highly accurate measurement can be performed.

[0044]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of an optical measuring apparatus according to the present invention.
1 is a configuration diagram showing a current measuring device as an embodiment of FIG.

In FIG. 1, 21 is a laser diode,
A fiber laser 25 is excited by the laser diode 21 and emits random polarized light. The light emitted from the fiber laser 25 is introduced into the transmission fiber 3. The light propagating through the transmission fiber 3 becomes parallel light by the coupling lens 4a, and is guided to the polarizer 5 installed near the sensor. In this case, since the randomly polarized light propagates through the transmission fiber 3, the amount of light transmitted through the polarizer 5 is always constant irrespective of the state of the transmission fiber 3, and linearly polarized light with a stable amount of light is introduced into the polarizer 5. can do.

The light linearly polarized by the polarizer 5 passes through the non-polarizing beam splitter 6 and is incident on the sensor fiber 8 by the coupling lens 4b. The sensor fiber 8 is arranged so as to orbit around the conductor 7 through which the current to be measured flows, and receives Faraday light by a magnetic field generated by the current.

On the other hand, a fiber reflecting mirror 9 is disposed at the end of the sensor fiber 8, and the measuring light reciprocates in the sensor fiber by the fiber reflecting mirror 9.

The light reflected from the sensor fiber by the fiber reflecting mirror 9 is split by the non-polarizing beam splitter 6 and enters a polarizing beam splitter (hereinafter abbreviated as PBS) 10. This PBS
10 indicates that the incident polarization direction is 45 when the Faraday irradiation angle is 0.
And two orthogonal intensity light signals are obtained from the light emitted from the sensor fiber.

This optical signal is supplied to the detector 11 of each axis.
The photoelectric conversion is performed by a and 11b, the current value is calculated by the electronic circuit 12, and this is output as a measurement signal.

As described above, in the first embodiment, the fiber laser 25 emitting random polarized light is used as the light source used for measurement, and the fiber laser 25 propagates the random polarized light to the transmission fiber 3. In addition, the light amount transmitted through the polarizer 5 is always constant, and linearly polarized light with stable light amount can be supplied to the sensor unit.

FIG. 2 shows a second embodiment of the optical applied measuring apparatus according to the present invention.
1 is a configuration diagram illustrating a voltage measurement device as an embodiment.

In FIG. 2, 21 is a laser diode,
A fiber laser 25 is excited by the laser diode 21 and emits random polarized light. The light emitted from the fiber laser 25 is introduced into the transmission fiber 3, sent to the vicinity of the voltage detection unit, and
The light becomes linearly polarized light at a.

Further, the light is converted into circularly polarized light by a fiber type quarter-wave plate 37, and then passed through an EO (electro-optical) element 49 provided corresponding to the voltage detector. This EO element 4
9 is a fiber type as shown in the figure. The light modulated by the EO element 49 is extracted as an intensity signal by the fiber polarizer 18b,
After the photoelectric conversion in step 1, the voltage is obtained by the electronic circuit 12,
The voltage signal is output.

According to the present invention, even in voltage measurement,
Although it is possible to realize high precision by using an all-optical fiber, the polarization of the light source needs to be random.

Conventionally, as a random light source for an optical fiber, a method of randomly polarizing an SLD with a LYOT type depolarizer has been widely used. The inventors have also tried this method initially. The result is shown in FIG.

When the transmission fiber is vibrated, the output of the optical voltage measuring device also changes accordingly, and the light amount also changes as shown in FIG. If this is replaced with an LED as a light source, the light quantity does not fluctuate as shown in FIG. 3B, and the accuracy of the photodetector (PD) is improved to 1/10 or more.

However, when an all-optical fiber is used, the light source needs to be coupled to a single mode fiber because the fiber polarizer and the fiber phase difference plate do not function unless they are single mode fibers. Since the LED has a large light emitting area and a large beam divergence angle, it hardly couples to a single mode fiber and cannot be used as a light source.

Therefore, it is desirable to use a single mode fiber type fiber laser or a spontaneous emission light of a fiber amplifier or its amplified light as a light source. A rod-type solid-state laser is also effective because it can increase the coupling with the optical fiber and can output random polarized light. VICSEL, which is being developed for optical communication, can also be a light source.

FIG. 4 shows an embodiment in which a random polarized light source is used as the light source. As shown in FIG. 4, the laser diode 26 for outputting the frequency λ1 and the frequency λ
The laser diode 27 that outputs 2 is arranged with the output polarization directions orthogonal to each other. When this output light is coupled to the polarization maintaining coupler 19, orthogonally polarized light is output.

Also, it is possible to obtain two orthogonally polarized waves with the configuration shown in FIG. 5 without using two light sources.

That is, as shown in FIG. 5, the light of the laser diode 21 is once branched by the fiber coupler 22 and is coupled again by the polarization maintaining fiber coupler 19.
At this time, a modulator 51 is provided on one optical path to shift the wavelength. Needless to say, at this time, the axes of incidence of the polarization maintaining fibers need to be orthogonal at both entrances.

According to the light source having such a configuration, the output of the laser diode can be used as it is, and a light source having a simpler configuration and higher reliability than the case of using a fiber laser or a solid-state laser can be realized.

At this time, since the oscillation wavelengths of the two laser diodes need to be close to each other, if a fiber diffraction grating is used as the reflection mirror of the laser diode resonator, the oscillation wavelength is fixed at the reflection wavelength of the diffraction grating. Can be stabilized.

Next, as a third embodiment of the optical applied measuring device according to the present invention, a temperature stabilizing device for a light source will be described.

A problem when a temperature change occurs in the conventional light measurement light source is that the spectrum shape changes with the change of the oscillation wavelength. In other words, if only the oscillation wavelength is used, it is possible to correct the temperature by measuring the temperature of the light source unit, but the change in the oscillation spectrum becomes a change in the output polarization state, especially when the device is once depolarized and used. Appears and the output becomes unstable, so that correction cannot be performed. In order to prevent this, it is necessary to stabilize the temperature of the light source.

FIG. 6 shows an example of the structure of such a light source temperature stabilizing device. A laser diode chip 28 and a thermistor 30 are provided on the upper surface of a Peltier cooler 29 mounted on a base 52, respectively. Diode chip 2
The temperature 8 is detected by the thermistor 30, and the temperature controller 32 controls the Peltier cooler 29 to perform cooling or heating according to the detected temperature, so that the temperature of the laser diode chip 28 is kept constant. I have.

The laser diode chip 28 is driven by the light source driver 1 and its oscillation light is output to the polarization maintaining fiber 33. At this time, the axis of the polarization maintaining fiber 33 is set to the output polarization direction of the laser. For 4
When set at an angle of 5 °, depolarized light is obtained as output light from the polarization maintaining fiber 33. The light source at this time is not limited to a laser diode,
Also in this case, the oscillation spectrum shape is stabilized by stabilizing the temperature, which is effective.

Further, when the light of the laser diode is depolarized and used, it is effective to modulate the drive current. This principle will be described with reference to FIG.

When the laser diode oscillating at the oscillation frequency ω0 is modulated at the frequency ω1, three oscillation frequency components ω0, ω0 + ω1, and ω0−ω1 are generated. If the light of each frequency component is to be depoilized, the light of each frequency has a coherence length of 1 km or more, making it difficult to depolarize.

However, if the light having a wavelength frequency width of 2ω1 is taken, the coherence length is C / 2ω1, and the coherence length is much shorter.

FIG. 8 shows the relationship between the laser modulation frequency and the coherence length. In FIG. 8, when the modulation frequency exceeds 10 MHz, the beat length becomes 1
5 m or less, which is a practical value.

For example, in order to depolarize this light, a depolarizer having a configuration as shown in FIG. 10 may be used. That is, it is preferable that the light emitted from the laser diode 21 is branched into two by the fiber coupler 19, an optical path length difference greater than the coherence length is provided, and the light is coupled again by the fiber coupler 19. At this time, it is more effective to shift the polarization planes of the two lights by 90 ° using the polarization plane holding fiber 33 and the like.

Next, an embodiment of a protection control device using the optical applied measurement device according to the present invention will be described.

FIG. 10 shows a first embodiment of a protection control device using a photocurrent measuring device as the optical applied measuring device according to the present invention. The light from the laser diode 21 is split by the optical fiber coupler 22, and the light is sent to the photocurrent measuring device sensor unit 23 and the photocurrent measuring device sensor unit 24 by the transmission fiber 3, respectively. The sensor section of the photocurrent measuring device contains the polarizer, beam splitter, sensor fiber, reflecting mirror, and the like already described, and receives the optical rotation due to the Faraday effect due to the current as a two-component light intensity signal orthogonal to xy. It has a function to send to The light from the receiving fiber is subjected to necessary calculations by the electronic circuit 12, and a current signal is input to the differential relay 60. The differential relay 60 operates when there is a difference between the respective current signals to protect a protection section between the photocurrent measuring device sensor unit 23 and the photocurrent measuring device sensor unit 24.

As described above, according to the protection control device using the photocurrent measuring device according to the present invention, the same laser diode is used for the two photocurrent measuring devices used for differential operation.
Regardless of the oscillation wavelength and spectrum shape of the laser diode, the two photocurrent measuring devices can output the same current value, and realize a protection control device that has small manufacturing variations and is stable even with temperature. it can. Also, even if there is mode hopping of the laser diode, the two current measuring devices generate the same error at the same timing,
It does not lead to errors in the protection control device. For this reason,
An accurate protection control device can be realized.

The present invention is not limited to a differential relay. For example, when three-phase alternating current is measured, the same light source is used for three photocurrent measuring devices used for measuring each phase. Since the characteristics of the photocurrent measuring devices can be matched, the zero-phase current can be accurately measured from the difference between the three current measuring devices.

FIG. 11 is a block diagram showing a second embodiment of the protection control device using the photocurrent measuring device according to the present invention.

As shown in FIG. 11, light from the two light sources 21 is once synthesized by the coupler 22, further branched by the coupler 22, and transmitted to the photocurrent measuring device sensor units 23 U, 23 V, and 23 W through the transmission fiber 3. Sent.
This photocurrent measuring device sensor unit 23U, 23V, 23W
Contains a polarizer, a beam splitter, a sensor fiber, a reflecting mirror, and the like, which have already been described, and sends out the optical rotation due to the Faraday effect due to the current to the receiving fiber as a two-component light intensity signal orthogonal to xy. The light from the receiving fiber is subjected to necessary calculations by the three-phase electronic circuits 12 to output the output currents of the respective phases independently and to a circuit 45 for calculating a zero-phase current from the current values of the three phases. ing.

In FIG. 10, only one light source is used.
Then, the light once synthesized is further branched by the coupler 22, so that light having the same characteristics is supplied to the three phases, and the same effect as that of FIG. 10 can be obtained.

In this example, the three-phase currents are output independently of each other, and at the same time, the zero-phase current is calculated from the three-phase current values by the arithmetic circuit 45. This zero-phase current is 0 during normal operation.
And if an error occurs in the current measuring device,
Because this error is output as the 0-phase current calculation value,
This is effective for testing whether the current measuring device is operating without error.

Further, in this example, since the zero-phase current is obtained from the sum current of three optical applied current measuring devices operating with the same light source, the influence of the light source can be ignored. For this reason, it is possible to monitor only an error in the electronic circuit portion after the light receiver.

As described above, even if the difference or the sum current is not the measurement object itself, the self-monitoring function of the measuring instrument can be performed using the sum or difference current, which is useful.

Further, the present invention is not limited to current measurement. For example, in the measurement of three-phase voltage, when applied to optical voltage sensors, the characteristics of the three optical voltage sensors can be made uniform. It goes without saying that accurate zero-phase voltage measurement can be performed.

FIG. 12 is a block diagram showing a third embodiment of the protection control device using the applied optical measuring device according to the present invention.

As shown in FIG. 12, light from a light source 21 is branched by a fiber coupler 22, one of which is provided to an optical section of an optical applied current measuring device (optical CT) sensor 23, and the other is applied to an optical applied voltage measuring device ( Light is supplied to the optical unit 49 of the light PD). The optical PD measures the line voltage divided by the voltage divider 46, and the optical CT measures the line current. A current value is calculated by the optical CT electronic circuit 48 from the light modulated by the current in the optical CT optical unit. The voltage value of the light modulated by the voltage in the optical PD optical unit is calculated by the optical PD electronic circuit 47. When the voltage / current is calculated based on the current and voltage signals, the impedance of the line can be obtained. For example, when a ground fault occurs in a line, if the impedance per distance of the line is known, the distance to the ground fault point can be obtained. Although this principle is widely used as the distance relay 50, since light from the same light source is used for the voltage / current signal at this time, for example, an increase of the light amount of the light source causes an error of + 10%. Even if the result of the division is the same as before the increase in the amount of light, accurate impedance measurement can be performed

[0087]

As described above, according to the present invention, it is possible to provide a highly accurate, compact, and highly stable optical application measuring device and a protection control device using the same.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a current measuring device as a first embodiment of an optical applied measuring device according to the present invention.

FIG. 2 is a configuration diagram showing a voltage measuring device as a second embodiment of the optical applied measuring device according to the present invention.

FIG. 3 shows an SLD and an L as light sources in the embodiment.
FIG. 9 is a waveform chart for explaining test results when an ED is used.

FIG. 4 is a configuration diagram showing an example of a random power supply in the embodiment.

FIG. 5 is a configuration diagram showing another example of the random power supply in the embodiment.

FIG. 6 is a configuration explanatory view of a temperature stabilizing device of a light source as a third embodiment of the optical applied measuring device according to the present invention.

FIG. 7 is a diagram for describing an operation principle of a light source in the embodiment.

FIG. 8 is a diagram showing a relationship between a laser modulation frequency and a coherence length in the same operation principle of the light source.

FIG. 9 is a configuration diagram showing a depolarizer for depolarizing light in the embodiment.

FIG. 10 is a configuration diagram showing a first embodiment of a protection control device using an optical applied measurement device according to the present invention.

FIG. 11 is a configuration diagram showing a second embodiment of the protection control device using the optical applied measurement device according to the present invention.

FIG. 12 is a configuration diagram showing a third embodiment of the protection control device using the optical applied measurement device according to the present invention.

FIG. 13 is a schematic configuration diagram showing an example of a current measuring device using a conventional optical current transformer.

FIG. 14 is a configuration diagram showing a conventional protection device using an iron core type current transformer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Light source driver 2 ... Light source 3 ... Transmission fiber 4 ... Coupling lens 5 ... Polarizer 6 ... Non-polarization beam splitter 7 ... Current to be measured 8 ... Sensor fiber 9 ... Fiber reflector 10 ... PBS 11a, 11b ... Detector 12 ... Electronic circuit 14 ... High birefringence fiber 15 ... Fiber diffraction grating 18a, 18b ... Fiber polarizer 19 ... Polarization plane maintaining coupler 20 ... Polarization separation coupler 21 ... Laser diode 22 ... Fiber coupler 23, 24 ... Photocurrent measuring device sensor unit 25 ... Fiber lasers 26,27 ... Laser diode 28 ... Laser diode chip 29 ... Peltier cooler 30 ... Thermistor 31 ... Cooling fins 32 ... Temperature controller 33 ... Polarization plane holding fiber 34 ... Faraday element 35 ... Coils 36 ... Faraday element 37 ... 1/4 wavelength plate 38 ... He-Ne laser 39 ... objective lens 40 ... bus 41 ... single mode fiber 42 ... Wollaston prism 43 ... detector 44 ... electronic circuit 45 ... zero phase monitoring circuit 46 ... voltage divider 47 ... light PD electronic circuit 48 ... Optical CT electronic circuit 49 ... Optical PD optical unit 50 ... Distance relay

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kiyoto Terai 2-1 Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Inside the Toshiba Hamakawasaki Plant (72) Inventor Sakae Ikuta 2, Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa No. 1 F-term in Toshiba Substation Equipment Technology Co., Ltd. (reference) 2G025 AA08 AB10 2G059 AA03 BB20 EE05 GG01 GG04 JJ11 JJ17 JJ19 JJ20 JJ30 KK01 5G047 AA01 AA11 AB02 AB07 CA01 CB03

Claims (14)

[Claims] 1. An optical applied measurement device for measuring a physical quantity from a change in the polarization characteristic of an optical element by utilizing a change in a polarization characteristic of an optical element due to a change in a physical quantity, emits random polarized light as a light source used for measurement. An optical application measurement device characterized by using a light source that emits light. 2. The optical applied measurement device according to claim 1, wherein the light source is a fiber. 3. The optical applied measurement device according to claim 1, wherein the light source is a rod-type solid-state laser. 4. An optical applied measurement device for measuring a physical quantity from a change in the polarization characteristic of an optical element by utilizing a change in the polarization characteristic of an optical element due to a change in a physical quantity, wherein the orthogonally polarized light is used as a light source for measurement. An optical applied measurement device characterized by using a light source that emits light. 5. The optical applied measuring apparatus according to claim 4, wherein the light source for emitting the two orthogonal polarizations is a laser diode and a polarization plane holding apparatus which is installed with the axis of birefringence aligned with the polarization direction of the laser diode. An optical applied measurement apparatus comprising: a fiber, a pair of laser diodes, and a polarization maintaining fiber, and a polarization maintaining fiber coupler connected to the birefringent fiber such that the output polarization directions of the birefringent fiber are orthogonal to each other. 6. The optical applied measurement device according to claim 4, wherein a fiber diffraction grating is used for a resonator of the laser diode as the light source. 7. An optical applied measurement apparatus for measuring a physical quantity from a change in the polarization characteristic of an optical element by utilizing a change in a polarization property of an optical element due to a change in a physical quantity, wherein a temperature is controlled as a light source used for measurement. An optical measuring device using SLD, wherein the output of the light source is depolarized by a depolarizing element. 8. A light source used for measurement in an optical applied measurement apparatus for measuring a physical quantity based on a change in the polarization characteristic of an optical element by utilizing a change in a polarization property of an optical element due to a change in a physical quantity. An optical measuring device using a laser diode, wherein the output of the light source is depolarized by a depolarizing element. 9. The optical applied measurement device according to claim 8, wherein the operation is performed by adding an AC component to the drive current of the laser diode. 10. The optical applied measurement device according to claim 9, wherein the frequency of the AC component is 10 MHz or more. 11. A protection control device for performing protection or control operation based on a difference signal between measurement signals measured by a plurality of optical applied measurement devices, wherein one light source is used as a light source for the plurality of optical applied measurement devices. A protection control device characterized in that light from a light source is branched and used. 12. The protection control device according to claim 11, wherein the optical applied measuring device is a current or voltage measuring device for measuring a polyphase alternating current, and the optical applied measuring device for measuring each phase voltage or current. A protection control device, wherein the same light source is used. 13. The protection control device according to claim 11, wherein the optical applied measurement device is used as a current measurement device to obtain a sum of currents flowing in and out of a protection section, and a protection operation is performed based on a value of the sum of the currents. A protection control device characterized by the above-mentioned. 14. A protection control device that performs a protection or control operation based on a ratio of measurement signals measured by a plurality of optical applied measurement devices, wherein a light from one light source is used as a light source for each of the optical applied measurement devices. A protection control device characterized in that it is used by branching.