JPH08110357A - Optical current measuring instrument - Google Patents

Abstract

PURPOSE: To accurately measure current flowing through a conductor even if the temperature of measurement atmosphere changes. CONSTITUTION: A sensor 11 such as an optical fiber generating Faraday effect is provided so that a conductor 3 provided in the insulation gas atmosphere in a closed tank 1 can be surrounded. Light from a light source 14 is applied to the sensor 11 as linear polarization through an optical fiber 12 for transmission and the emission light from the sensor 11 is detected for obtaining the rotary angle for the polarization surface of linear polarization proportional to the magnetic field generated from the conductor 2, and measuring thereby the current flowing to the conductor 2. Pipes 35 and 42 with improved thermal conductivity for circulating and flowing a refrigerant are provided near the sensor 11 and at the same time heat pumps 38 and 39 are provided at the circulation path of the pipe, thus controlling the refrigerant temperature so that the temperature of the sensor part approaches a certain temperature by the heat pumps.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical current measuring device for measuring a current flowing through a conductor by using light.

[0002]

2. Description of the Related Art Conventionally, as a measuring device for a power system using light, for example, a lead glass or quartz block is used as a sensor or is wound in a loop shape so as to surround the conductor in the vicinity of the conductor. There is a sensor in which an optical fiber arranged in a rotating manner is used as a sensor, and linearly polarized light is allowed to pass through the sensor to measure the polarization angle of the Faraday effect caused by a measured current flowing in a conductor.

FIG. 11 shows a configuration example of a conventional optical current measuring device using a block of lead glass or quartz as a sensor. In FIG. 11, a sensor 3 made of lead glass or a quartz block is arranged inside the GIS tank 1 so as to surround the conductor 2. This sensor 3 is fixed to a fixture 4, and since the conductor 2 has a high voltage, it is attached by being insulated from the ground potential by an insulating cylinder 5 made of an insulating material.

Light emitted from a light source (not shown) passes through the light transmitting fiber 6 and becomes a linearly polarized light beam 8 of a substantially parallel light beam in the coupling optical system 7 including a lens and a polarizer and propagates in the space. Incident on the sensor 3 and repeatedly reflected inside, and then emitted from the sensor 3. Meanwhile, the light passing through the inside of the sensor 3 rotates by a certain angle due to the Faraday effect induced by the current flowing through the conductor 2.

The emitted light becomes a linearly polarized beam 9, propagates in space, travels again to the coupling optical system 7, passes through an analyzer and a lens, and then enters a light receiving fiber 10. Note that the configuration and operation of the coupling optical system 7 described here are already known items, and therefore description thereof will be omitted here.

On the other hand, the optical fiber used for the sensor is usually coated with a resin such as acrylic, polyamide, or polyimide for reinforcement or environmental resistance improvement. Furthermore,
When the optical fiber is fixed to the sensor winding frame or the like, it is protected and fixed with an adhesive containing epoxy resin or acrylic resin as a main component.

These resin materials are 20 × 10 ^{−6 to} 100 ×
10 ^-6 , 0.7 of silica glass which is the material of the fiber
It is remarkably large as compared with × 10 ^-6 . Therefore, if the temperature changes, thermal stress is generated in the fiber portion. Especially when fixed and protected with an adhesive, the cross-sectional area of the fiber (fiber diameter is about 0.1 mm to 0.2 mm is extremely thin) is overwhelmingly small compared to the cross-sectional area of the adhesive, so Larger thermal stress is generated.

It has been found that the polarization characteristics of the fiber are significantly deteriorated by the thermal stress generated in the cross section of the fiber. This is usually referred to as an increase in birefringence, and will be referred to as such. Further, the temperature change also deteriorates the original characteristics of the fiber itself.

[0009]

The mechanism for increasing the birefringence due to the thermal stress is as follows. Ordinary light can be represented by two polarization planes (vectors) of the X axis and the Y axis. That is, when normal light passes through the polarizing element, it becomes light having one polarization plane (this is called linearly polarized light). If this plane of polarization is assumed to be the X axis and this linearly polarized light is made incident on an optical element such as glass while applying a force from the outside, the light that emerges will have a vector also in the Y axis direction.

The reason for this is that the traveling speed of light in the optical element changes depending on the refractive index of the light, and the refractive index of light also changes due to the stress in the cross section of the passing element. In other words, the traveling speed of light is X at each location due to thermal stress.
This is because birefringence occurs due to changes in the axis and the Y axis.

As described above, since the conventional optical fiber is protected by resin coating, and is protected and fixed by the adhesive, the thermal stress generated in the cross section of the fiber due to the temperature change of the atmosphere at the installation site causes the traveling speed of light to be increased. There is a drawback that the birefringence occurs and the measurement accuracy is lowered.

The present invention provides an optical current measuring device capable of highly accurately measuring a current flowing through a conductor in a sensor using such a block made of optical glass, an optical fiber or the like, even if the temperature of a measurement atmosphere changes. The purpose is to do.

[0013]

In order to achieve the above object, the present invention constitutes an optical current measuring device by the following means. The invention corresponding to claim 1 is provided with a sensor such as an optical fiber which produces a Faraday effect so as to surround a conductor arranged in an insulating gas atmosphere in a closed tank, and the sensor is provided with an optical fiber for transmission from the light source. Is an optical system for measuring the current flowing through the conductor by detecting the light emitted from the sensor as the linearly polarized light and obtaining the rotation angle with respect to the polarization plane of the linearly polarized light proportional to the magnetic field generated from the conductor. In the current measuring device,
A pipe with good thermal conductivity is arranged near the sensor to circulate and flow the refrigerant, and a heat pump is provided in the circulation path of the pipe, and the heat pump controls the temperature of the refrigerant so that the sensor unit approaches a constant temperature. To do.

According to a second aspect of the invention, a temperature detector is provided in the vicinity of the sensor section, and the throttle opening is adjusted in the circulation path of the pipe based on the temperature detection signal from the temperature detector. A throttling mechanism having a throttling valve is provided.

According to a third aspect of the present invention, a throttle mechanism having a throttle valve using a memory alloy that is reversibly deformed with temperature is provided in the circulation path of the pipe. The invention corresponding to claim 4 is provided with a sensor such as an optical fiber that produces a Faraday effect so as to surround a conductor arranged in an insulating gas atmosphere in a closed tank, and the sensor is provided with an optical fiber for transmission through the sensor. Is an optical system for measuring the current flowing through the conductor by detecting the light emitted from the sensor as the linearly polarized light and obtaining the rotation angle with respect to the polarization plane of the linearly polarized light proportional to the magnetic field generated from the conductor. In the current measuring device, a pipe with good thermal conductivity is arranged that surrounds the vicinity of the sensor and is drawn out to the outside, and a refrigerant is injected into the inside to close the sensor side end and the outside side end, respectively. Further, a radiation fin or a heat exchanger is provided at the outer end.

According to a fifth aspect of the invention, a temperature detector is provided in the vicinity of the sensor section of the invention according to the fourth aspect, and the pipe is opened based on the temperature detection signal from the temperature detector. A throttling mechanism having a throttle valve whose degree is adjusted is provided.

The invention according to claim 6 provides the pipe of the invention according to claim 4 with a throttle mechanism having a throttle valve using a memory alloy which is reversibly deformed with respect to temperature. In the invention corresponding to claim 7, a sensor such as an optical fiber that produces a Faraday effect is provided so as to surround a conductor arranged in an insulating gas atmosphere in a closed tank, and a light source is passed through the sensor through a transmission optical fiber. Is an optical system for measuring the current flowing through the conductor by detecting the light emitted from the sensor as the linearly polarized light and obtaining the rotation angle with respect to the polarization plane of the linearly polarized light proportional to the magnetic field generated from the conductor. In the current measuring device, a ring made of a metal material that flows an induction current generated by electromagnetic induction by a current flowing in the conductor is arranged in the vicinity of the sensor, and a part of the ring is cut out to form a ring at the cut end. A switch is provided which has a contact piece that opens when it expands due to a rise in temperature and contracts when it expands due to a decrease in temperature.

The invention according to claim 8 is provided with a sensor such as an optical fiber that produces a Faraday effect so as to surround a conductor arranged in an insulating gas atmosphere in a closed tank, and this sensor is provided with a transmission optical fiber. The light flowing from the light source is incident as linearly polarized light through this, and the current flowing in the conductor is measured by detecting the light emitted from this sensor and determining the rotation angle with respect to the plane of polarization of the linearly polarized light proportional to the magnetic field generated from the conductor. In the optical current measuring device described above, at least one of a heating device such as a heater and an electronic cooling device is arranged near the sensor.

[0019]

In the optical current measuring device of the invention according to claim 1, the heat pump circulates the refrigerant through a pipe having good thermal conductivity arranged near the sensor,
In addition, by controlling the refrigerant temperature so that the sensor portion approaches a constant temperature, it is possible to reduce the thermal stress generated due to the difference in thermal expansion between the sensor and the adhesive that fixes the sensor. It is possible to mitigate the increase in the birefringence of the sensor and the increase of the birefringence of the sensor itself caused by the temperature change.

In the optical current measuring device of the invention according to claim 2, the throttle mechanism provided in the circulation path of the pipe based on the temperature detection signal from the temperature detector provided in the vicinity of the sensor section. By adjusting the throttle opening of the throttle valve, it is possible to stabilize the temperature of the sensor unit at approximately the set temperature.

In the optical current measuring device of the invention according to claim 3, the memory valve that reversibly deforms the throttle valve of the throttle mechanism provided in the circulation path of the pipe is used. , It becomes possible to adjust the throttle opening of the throttle valve without using the drive source for driving the throttle valve,
It is possible to stabilize the temperature of the sensor unit at approximately the set temperature.

In the optical current measuring device of the invention according to claim 4, the thermal conductivity is arranged so as to surround the vicinity of the sensor, and the sensor side end and the outer side end are closed. By disposing a radiating fin or heat exchanger at the outer end of a good pipe and injecting the refrigerant into the inside of the pipe, the heat of the refrigerant moves upward to the radiating fin or heat exchanger. Since the temperature of the pure water whose temperature has risen due to the heat radiating action of the heat radiating fins or the heat exchanger decreases, the birefringence and the increase in the birefringence of the sensor itself caused by the temperature change can be alleviated.

In the optical current measuring device of the invention according to claim 5, the throttle mechanism provided in the circulation path of the pipe based on the temperature detection signal from the temperature detector provided in the vicinity of the sensor section. By adjusting the throttle opening of the throttle valve, it is possible to stabilize the temperature of the sensor unit at approximately the set temperature.

In the optical current measuring device of the invention according to claim 6, by using a memory alloy that reversibly deforms the throttle valve of the throttle mechanism provided in the circulation path of the pipe with respect to temperature. , It becomes possible to adjust the throttle opening of the throttle valve without using the drive source for driving the throttle valve,
It is possible to stabilize the temperature of the sensor unit at approximately the set temperature.

In the optical current measuring device of the invention according to claim 7, one of the rings made of a metal material is disposed in the vicinity of the sensor and flows an induction current generated by electromagnetic induction by a current flowing through the conductor. When the contact piece 3 notched and attached to the notched end is thermally expanded due to the temperature rise of the ring, the contact piece 3 is opened, and the contact piece 3 is thermally contracted due to the temperature decrease, so that the maximum or minimum temperature of the fiber reel is alleviated. , Can be controlled to a substantially constant temperature.

In the optical current measuring device of the invention according to claim 8, the temperature of the fiber reel is maximized by at least one of a heating device such as a heater and an electronic cooling device arranged near the sensor. The temperature or the minimum temperature is relaxed, and the temperature can be controlled to be almost constant.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a structural example of an optical current measuring device to which the present invention is applied. In FIG. 1, a sensing fiber portion 11 is arranged on the outer periphery of a gas-insulated switchgear (hereinafter simply referred to as GIS) tank 1 so as to surround the conductor 2. From the sensing fiber portion 11, one ends of a light-sending fiber 12 and a light-receiving fiber 13 (in the figure, one is shown, but actually two) are connected, and the other end of the light-sending fiber 12 is connected to a light source ( A laser diode or a super luminescent diode) 14 is connected to the detector 14. The other end of the light-receiving fiber 13 is a detector (only one channel is shown in the figure, but it is actually two channels) 1.
Connected to 5. Then, the signal detected by the detector 15 is processed by the signal processing circuit 16 to obtain the value of the current flowing through the conductor 2, and this is output from the output terminal 17. The light source 14, the detector 15, and the signal processing circuit 16 form an optical processing device 18.

FIG. 2 is a view showing the optical system of the sensing fiber section 11. As shown in FIG. 2, the optical processing device 18
The light from the light source 14 is guided into the coupling optical box 19 of the sensing fiber portion 11 through the light transmitting fiber 12.
The light guided into the coupling optical box 19 is collimated by the lens 20a and then linearly polarized by the polarizer 21a and reaches the lens 20b. The light beam condensed by the lens 20b is guided via the holder 22 to the optical fiber 23 arranged around the conductor 2, and again by the reflecting material 24 arranged at the terminal end of the optical fiber 23, the original light beam is returned. Return to the optical path.

The light beam returned to this optical path is reflected by the beam splitter 25a in the coupling optical box 19 and further divided into two by this beam splitter 25a, and the respective lights are placed in the analyzers 21b arranged at right angles to each other. , 2
After passing through 1c, it is guided to the light receiving fiber 13 by the lenses 20c and 20d.

The light emitted from the light receiving fiber 13 is received by the detectors 15a and 15b, and the signal processing circuit 16
After being subjected to arithmetic processing by, the result is output from the output terminal 17.

Since the operation of the optical processing device 18 at the time of measuring the current is not directly related to the gist of the present invention, its explanation is omitted. Next, a first embodiment in which the present invention is applied to the optical current measuring device having the above configuration will be described with reference to FIGS. 3 and 4.

FIG. 3 is a perspective view showing a state in which only the temperature adjusting device according to the first embodiment of the present invention is taken out, and FIG. 4 is a sectional view taken along the line AA of FIG. 3 and 4
As shown in FIG. 3, an optical fiber winding frame 26 having a U-shaped cutout groove on the inner diameter side is connected between the connection flanges 1a of the GIS tank 1 in an airtight manner on the flange joint surface via an O-ring 27.

A spiral groove is provided on the outer peripheral surface of the optical fiber winding frame 26. The sensing fiber 23 is inserted into the groove and wound plural times, and is fixed by an adhesive material 30. Further, an insulating cover 31 is provided on the outer peripheral portion of the fiber winding frame 26 so as to surround the sensing fiber 23. In this case, the insulating cover 31 and the sensing fiber 2
A space portion 32 is formed between the space portion 3 and the space 3.

A conductive cover 34 is provided from the outer surface side of the connecting flange 1a so as to surround the insulating cover 31, and the connecting flanges are integrally connected by a bolt 29 via an insulating collar 28. In this case, the heat insulating material 3 is provided in the space between the insulating cover 31 and the conductive cover 34.
3 is filled.

On the other hand, a copper pipe 35 for flowing a coolant is inserted into the U-shaped notch groove of the fiber winding frame 26 in a state of one turn, and the space is filled with an epoxy resin 47 mixed with aluminum nitride. , Cured.

One end of such a copper pipe 35 is drawn out and connected to the inlet side of the compressor 36, and its outlet side is sequentially connected to the condenser 38 and the evaporator 39 via the throttling mechanism 37, and the final end is made of copper. It is connected to the outlet side pipe 42 connected to the other end of the pipe 35. Here, the condenser 38 and the evaporator 39 have a function as a so-called heat pump.

The aperture mechanism 37 includes a fiber winding frame 26.
When a reel temperature detection signal detected by the temperature detector 41 attached to is input, a mechanism is added to open and close the throttle valve driven by the motor based on the set temperature.

Next, the operation of the optical current measuring device according to the first embodiment constructed as described above will be described. Now, the refrigerant cooled by the evaporator 39 is supplied to the copper pipe 35 through the pipe outlet 42, goes through the fiber winding frame 26, and then enters the compressor 36, where it is compressed and is further compressed.
It is assumed that the fluid is circulated through a path of being condensed by the condenser 38 through 7 and returning to the evaporator 39.

In such a state, the temperature detector 4
When the temperature of the fiber reel 26 detected by No. 1 becomes higher than the set temperature of 25 ° C., for example, the opening degree of the throttle valve of the throttle mechanism 37 becomes large, and the copper pipe 35 is passed from the outlet side pipe 42 through the condenser 38 and the evaporator 39. The amount of refrigerant flowing into the tank increases. For this reason, the temperature of the fiber reel 26 decreases.

When the temperature of the fiber reel 26 falls below 20 ° C., for example, and the temperature detection signal is input to the throttling mechanism 37, the throttle valve opening decreases, and the copper pipe is passed through the outlet side pipe 42 from the heat pump. The amount of refrigerant flowing into the pipe 35 decreases, and the temperature of the fiber reel 26 stops decreasing.

By repeating such temperature adjustment, the temperature of the optical fiber sensor section can be stabilized at approximately 25 ° C. As described above, by adjusting the opening degree of the throttle valve of the throttle mechanism 37 to stabilize the temperature of the optical fiber sensor unit at the set temperature of 25 ° C., it is particularly effective in regions with high average temperature such as tropical regions. .

Although the above-mentioned case is a usage form in a region where the average temperature is high, the reverse operation is required in a cold region. Therefore, when performing the operation reverse to the above-described operation, the arrangement of the compressor 36, the throttle mechanism 37, the condenser 38, and the evaporator 39 is replaced, or the copper pipe 35 is provided between the condenser 38 and the evaporator 39. By changing the connection of the outlet side pipe 42, the heated refrigerant flows through the copper pipe 35 in the fiber winding frame 26, so that the temperature of the same part can be raised and the temperature can be stabilized even in cold regions. Becomes Such connection change can be easily realized by normally changing the inflow direction of the refrigerant by an electromagnetic valve mechanism.

Therefore, with such a structure, the thermal stress generated due to the difference in thermal expansion between the optical fiber and the adhesive fixing the optical fiber can be reduced, so that the birefringence increased by the mechanism described in the prior art, It is possible to mitigate the increase in birefringence of the optical fiber itself caused by the temperature change.

Further, due to these effects, even when the apparatus is installed in a low temperature environment of up to 40 ° C. below freezing in a cold region, the temperature changes of the device due to the ambient temperature, even if it is installed in a low temperature environment of 40 ° C. below freezing in direct sunlight. Since it can be relaxed, the deterioration of the polarization characteristics in the optical fiber sensor section can be suppressed to a small level, and the measurement accuracy can be further increased.

FIG. 5 is a sectional view similar to FIG. 3 in which only the temperature adjusting device in the second embodiment of the present invention is taken out. The same parts as those in FIG. ,
Here, different parts will be described.

In the second embodiment, as shown in FIG. 5, a copper pipe 48 for flowing a coolant is inserted into a U-shaped groove formed in the fiber winding frame 26 with one turn, and the space is nitrided. An epoxy resin 47 mixed with aluminum is filled and cured.

One open end of the copper pipe 48 is closed, the other end side is penetrated through the upper part of the flange 1a of the tank 1 and drawn out to the outside, and is connected to one end of the throttle mechanism 37. A copper pipe 48 rises vertically from the other end to the tank 1, and a radiation fin 40 is attached to the outer peripheral surface of the extended portion of the copper pipe 48 to form a so-called heat pipe. Block.

The diaphragm mechanism 37 includes a fiber winding frame 26.
When a reel temperature detection signal detected by the temperature detector 41 attached to is input, a mechanism is added to open and close the throttle valve driven by the motor based on the set temperature.

In the copper pipe 48, an amount of ultrapure water (electrical resistance of 16 megohm · cm at 25 ° C.) corresponding to a volume of about 90% of the space inside the pipe is injected. Next, the operation of the optical current measuring device according to the second embodiment configured as described above will be described.

The heat of the fiber reel 26 is transferred to the ultrapure water in the copper pipe 48 by heat conduction. Now, assuming that the throttle mechanism 37 is set to operate when the temperature of the fiber reel 26 reaches 40 ° C. or higher, the valve of the throttle mechanism 37 operates when the temperature detected by the temperature detector 41 is 40 ° C. or higher. open.
Then, the copper pipe 48 provided in the fiber reel 26
The ultrapure water in the inside rapidly moves to the side of the copper pipe 48 having a low temperature to which the radiation fin 40 is attached. Such a phenomenon is already known.

At this time, the heat of the pure water moves upward to the radiating fins 40, and the temperature of the pure water whose temperature has risen due to the radiating action of the radiating fins 40 decreases. Then, when the temperature of the fiber reel 26 decreases, the valve of the throttle mechanism 37 closes.

By repeating such an action, the temperature of the fiber reel 26 is controlled to be constant.
It is possible to obtain the same effect as that of the first embodiment. FIG. 6 is a perspective view showing only the temperature adjusting device in the third embodiment of the present invention, and FIG. 7 is a sectional view taken along the line BB of FIG.

As shown in FIGS. 6 and 7, the fiber reel 26 is hermetically provided between the connection flanges 1a of the GIS tank 1 on the flange joint surface via the O-ring 27. A spiral groove is provided on the outer peripheral surface of the fiber winding frame 26, and the sensing fiber 23 is wound into the groove a plurality of times while being fixed, and is fixed by an adhesive material 30. Also,
An insulating cover 31 is provided on the outer periphery of the fiber winding frame 26 so as to surround the sensing fiber 23. In this case, a space 32 is formed between the insulating cover 31 and the sensing fiber 23.

Next, a copper ring 43 is provided on the outer peripheral portion of the GIS tank 1 adjacent to the fiber reel 26. The copper ring 43 has a part notched, and contact pieces 44a and 44b constituting a switch 44 are attached to both ends of the notch. This switch 44 has a copper surface plated with silver. When the temperature of the ring rises above about 40 ° C., the contact pieces 44a and 44b of the switch 44 become non-contact due to thermal expansion, and when the temperature rises above about 20 ° C. The size, shape, and notch interval of the ring 43 are set so that the contact pieces 44a and 44b of the switch 44 are brought into contact with each other due to thermal contraction of the ring 43.

The conductive cover 3 surrounds the insulating cover 31 and the ring 43 from the outer surface side of the connection flange 1a.
4 is provided, and the bolt 29 is provided through the insulating collar 28.
The connecting flanges are integrally connected by. In this case, the space between the insulating cover 31 and the conductive cover 34 is filled with the heat insulating material 33, and the ring 43 is supported by the heat insulating material 33.

Next, the operation of the optical current measuring device according to the third embodiment constructed as described above will be described. Now, the contact piece 4 of the switch 44 provided at the notched end of the ring 43
When 4a and 44b are in contact with each other, the conductor 2
Ring 43 when receiving electromagnetic induction by the magnetic flux generated from
Since an induction current flows through the ring, the temperature of the ring 43 rises due to its Joule heat. Eventually, when the temperature of the ring 43 reaches about 40 ° C., the ring 43 is deformed in the direction in which the diameter of the ring increases due to thermal expansion.
And 44b are separated.

Then, since the loop of the ring 43 is broken, the induced current hardly occurs, and the temperature of the ring 43 and the fiber winding frame 26 decreases. Eventually, ring 43
When the temperature of the switch drops to about 25 ° C, the ring 43 returns to its original state due to heat contraction, and the contact piece 44 of the switch 44
The a and 44b come into contact with each other, and an induced current again flows through the ring 43 to generate heat.

By repeating such an operation, the maximum temperature or the minimum temperature of the temperature of the fiber winding frame 26 is relaxed, and the temperature is controlled to a substantially constant temperature. Therefore,
With such a configuration, it is possible to control the temperature in the cold region as in the first embodiment.

FIG. 8 is a sectional view similar to FIG. 3 in which only the temperature adjusting device in the fourth embodiment of the present invention is taken out. The same parts as those in FIG. 7 are designated by the same reference numerals and their description is omitted. ,
Here, different parts will be described.

In the fourth embodiment, as shown in FIG. 8, the cartridge heater 45 and the electronic cooler 46 are provided in the U-shaped notch groove provided on the inner diameter side of the fiber winding frame 26 with an appropriate interval. They are inserted side by side, and the space is filled with an epoxy resin 47 mixed with aluminum nitride and cured.

A temperature detector 41 is provided near the fiber reel 26, and the reel temperature detection signal detected by the temperature detector 41 is input to a temperature controller (not shown). When the reel temperature detection signal is input, the temperature control device energizes the cartridge heater 45 or the electronic cooler 46 based on the set temperature to heat the fiber reel 26 when the temperature is lower than 25 ° C. When it is high, it is cooled and controlled to a constant temperature close to 25 ° C.

In the optical current measuring device having the structure according to the fourth embodiment, the temperature of the fiber reel 26 is 2 degrees.
When the temperature is lower than 5 ° C, a current flows through the heater 45 to increase the temperature of the fiber reel 26, and when the temperature is higher than 25 ° C, the electronic cooler 46 is operated to cool the fiber reel 26 to cool the fiber. Since the temperature of the winding frame 26 can be controlled to a constant temperature close to 25 ° C., the same effect as that of the first embodiment described above can be obtained.

Copper was used as the material for the heat exchange pipes connected to the heat pump described in the first embodiment and the heat pipe described in the second embodiment, but any material having good heat conduction may be used. If other materials are used, the same effect can be exhibited. For example, when a metal cannot be used due to an electric field or magnetic field generated by a large current, beryllia (BeO), aluminum nitride (AlN), or the like, which is an insulating material but has good thermal conductivity, may be used.

Further, in the first, second and fourth embodiments, the pipes 35 and 48 inserted in the groove provided on the inner diameter side of the fiber winding frame 26, the cartridge heater 45 and the electronic type. The cooler 46 was fixed by an adhesive agent in which an epoxy resin was filled with aluminum nitride powder having good thermal conductivity. However, as the resin material, silicone rubber or other materials called engineering plastics were BeO or Al.
By filling powders of N, mica, etc., the thermal conductivity can be greatly improved and the function can be sufficiently exhibited.

Further, in the first and second embodiments, the case where the throttle valve of the throttle mechanism 37 is driven by the motor has been described, but the memory alloy which is reversibly deformed by temperature is used to reversibly drive the throttle valve. The valve may be driven by utilizing the energy for deformation, or the valve may be formed by a direct memory alloy.

Although the respective embodiments when applied to one optical measuring system have been described above, other optical measuring systems as shown in FIGS. 9 and 10 can be implemented in the same manner as described above.

That is, in FIG. 9, the laser light emitted from the light source 14 enters the optical integrated circuit 51 after passing through the fiber branch point 50. The optical integrated circuit 51 includes a polarizer 5
2 and phase modulators 53a and 53b, and the phase modulators 53a and 53b send a modulation signal by the modulation circuit 54. The two laser beams emitted from the optical integrated circuit 51 pass through the quarter-wave plates 55a and 55b, respectively, and then pass through the sensing fiber 23 which also serves as a light-transmitting / receiving fiber, reach the sensing fiber portion 11, and reach the conductor 2. After propagating in the opposite directions, the light returns to the optical integrated circuit 51 through different optical paths, passes through the fiber branch point 50, and is received by the detector 15d.

This system is a so-called interference type optical current transformer, which detects the phase difference due to the Faraday effect of the laser light that rotates around the conductor 2 in the clockwise and counterclockwise directions by the light intensity. The output of 15d is the control / signal processing circuit 16
After being calculated in b, the measurement result is output from the output terminal 17.

With respect to such an optical measurement system as well, by applying each of the above-described embodiments to the sensing fiber portion 11 installed apart from the optical processing device 18, the same operational effect is obtained. Obtainable.

Further, in FIG. 10, the laser light emitted from the light source 14 passes through the light transmitting / receiving fiber 61, is linearly polarized by the polarizer 62 of the sensing fiber portion 11 and is incident on the depolarizer 63 a, and enters the sensing fiber 23. After being guided and passing through the depolarizer 63b again, it is returned to the original optical path again by the reflecting material 64 arranged at the end of the fiber. The returned laser light passes through the fiber 61 for transmitting and receiving light, is branched at the fiber branch point 65, and is detected by the detector 15c.
After being received by, the signal processing circuit 16a performs an operation and outputs the operation result from the output terminal 17.

In the present system, the light intensity at the detector 15c is represented by the cosine function (cos2θ _f ) of the Farade optic angle θ _f generated by the current to be measured, and accurate measurement is possible.

With respect to such an optical measuring system, the same operational effect can be obtained by applying the above-mentioned respective embodiments to the sensing fiber portion 11 installed apart from the optical processing device 18. Obtainable.

In each of the above-mentioned embodiments, the case where the present invention is applied to the current measuring device for measuring the polarization angle of the Faraday effect caused by the measured current flowing through the conductor using the optical fiber as the sensor has been described. As shown in Fig. 3, a lead glass or quartz block is used as a sensor near the conductor, and the light from the light source enters this sensor through a transmission optical fiber and enters through a coupling optical system consisting of a lens and a polarizer, and then exits from this sensor. The light that is coupled through the optical system is the analyzer,
In a measurement system in which the light is transmitted through the lens and then incident on the light receiving fiber to measure the current, if the present invention is applied to the sensor in the same manner as described above, the thermal stress generated due to the difference in thermal expansion from the fixing member fixing these is reduced. It can be kept low, and the same effect as described above can be obtained.

[0074]

As described above, according to the present invention, in a sensor using a block made of optical glass, an optical fiber or the like, the current flowing through the conductor can be measured with high accuracy even if the temperature of the measurement atmosphere changes. It is possible to provide an optical current measuring device capable of performing the above.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an outline of an optical current measuring device to which the present invention is applied.

FIG. 2 is a configuration diagram showing an optical system of a sensing fiber portion of the current measuring device.

FIG. 3 is a perspective view showing a temperature adjusting device according to the first embodiment of the present invention.

FIG. 4 is a sectional view taken along the line AA of FIG.

FIG. 5 is a sectional view similar to FIG. 4, showing a temperature adjusting device according to a second embodiment of the present invention.

FIG. 6 is a perspective view showing a temperature adjusting device according to a third embodiment of the present invention.

FIG. 7 is a sectional view taken along the line BB of FIG.

FIG. 8 is a sectional view similar to FIG. 7, showing a temperature adjusting device in a fourth embodiment of the present invention.

FIG. 9 is a configuration diagram showing another example of the optical system.

FIG. 10 is a configuration diagram showing still another example of the optical system.

FIG. 11 is a configuration diagram showing a conventional optical current measuring device.

[Explanation of symbols]

1 ... GIS tank, 2 ... conductor, 11 ... sensing fiber part, 12 ... light transmitting fiber, 13 ... light receiving fiber, 14 ... light source, 15 ... detector, 16 ... signal processing circuit , 17 ... Output terminal, 18 ... Optical processing device, 19 ... Coupling optical box, 20a, 20b ... Lens,
21a, 21b, 21c ... Polarizer, 22 holder, 23
...... Optical fiber, 24 ...... Reflective material, 25a, 25b ......
Beam splitter, 26 ... Optical fiber reel, 27 ...
O-ring, 28 ... Insulation collar, 29 ... Bolt, 30
...... Adhesive, 31 …… Insulation cover, 32 …… Space, 3
3 ... Insulating material, 34 ... Conductive cover, 35 ... Copper pipe, 36 ... Compressor, 37 ... Throttling mechanism, 38 ... Condenser, 39 ... Evaporator, 40 ... Radiating fin, 41 ...... Temperature detector, 42 ...... Exit side pipe, 43 ...... Ring, 4
4 ... switch, 45 ... heater, 46 ... electronic cooler, 47 ... epoxy resin, 48 ... copper pipe.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location H02B 13/06 E (72) Inventor Sakae Ikuta 2-1, Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Inside the Toshiba Hamakawasaki Factory (72) Inventor Masao Takahashi 2-1, Ukishimacho, Kawasaki-ku, Kanagawa Prefecture No.1 Incorporated company Toshiba Hamakawasaki factory (72) Inventor Hiroshi Miura 2-1, Ukishimacho, Kawasaki-ku, Kawasaki-shi, Kanagawa Incorporated company Toshiba Hamakawasaki factory

Claims (8)

[Claims] 1. A sensor such as an optical fiber that produces a Faraday effect is provided so as to surround a conductor arranged in an insulating gas atmosphere in a closed tank, and a light from a light source is linearly passed through this sensor through an optical fiber for transmission. In an optical current measuring device for measuring the current flowing in the conductor by detecting the light emitted from the sensor, which is incident as polarized light, and obtaining the rotation angle with respect to the polarization plane of the linearly polarized light proportional to the magnetic field generated from the conductor. , A pipe having good thermal conductivity is arranged in the vicinity of the sensor to circulate and flow the coolant, and a heat pump is provided in the circulation path of the pipe, and the coolant temperature is controlled so that the sensor unit approaches a constant temperature by the heat pump. An optical current measuring device characterized by being controlled. 2. The temperature sensor according to claim 1, wherein a temperature detector is provided in the vicinity of the sensor portion, and the throttle opening is adjusted in the circulation path of the pipe based on a temperature detection signal from the temperature detector. An optical current measuring device, characterized in that a throttle mechanism having a throttle valve is provided. 3. The optical current according to claim 1, wherein the circulation path of the pipe is provided with a throttle mechanism having a throttle valve using a memory alloy that reversibly deforms with temperature. Measuring device. 4. A sensor such as an optical fiber that produces a Faraday effect is provided so as to surround a conductor arranged in an insulating gas atmosphere in a closed tank, and a light from a light source is linearly passed through this sensor through an optical fiber for transmission. In an optical current measuring device for measuring the current flowing in the conductor by detecting the light emitted from the sensor, which is incident as polarized light, and obtaining the rotation angle with respect to the polarization plane of the linearly polarized light proportional to the magnetic field generated from the conductor. , Arranging a pipe having good thermal conductivity which surrounds the vicinity of the sensor and is drawn out to the outside, and injects a refrigerant into the inside to close the sensor side end and the outside side end, respectively, and An optical current measuring device characterized in that a radiation fin or a heat exchanger is provided at the end portion on one side. 5. The throttle according to claim 4, wherein a temperature detector is provided in the vicinity of the sensor section, and the throttle opening is adjusted in the pipe based on a temperature detection signal from the temperature detector. An optical current measuring device comprising a throttle mechanism having a valve. 6. The optical current measuring device according to claim 4, wherein the pipe is provided with a throttle mechanism having a throttle valve using a memory alloy that is reversibly deformed with respect to temperature. 7. A sensor such as an optical fiber that produces a Faraday effect is provided so as to surround a conductor arranged in an insulating gas atmosphere in a closed tank, and a light from a light source is linearly passed through this sensor through an optical fiber for transmission. In an optical current measuring device for measuring the current flowing in the conductor by detecting the light emitted from the sensor, which is incident as polarized light, and obtaining the rotation angle with respect to the polarization plane of the linearly polarized light proportional to the magnetic field generated from the conductor. A ring made of a metal material that flows an induction current generated by electromagnetic induction due to a current flowing in the conductor is arranged in the vicinity of the sensor, and a part of the ring is cut out to cause thermal expansion due to temperature rise of the ring at the cut end. Then, an optical current measuring device is provided, which is equipped with a switch with which a contact piece that is opened and then contracts by heat due to temperature drop is attached. . 8. A sensor such as an optical fiber that produces a Faraday effect is provided so as to surround a conductor arranged in an insulating gas atmosphere in a closed tank, and a light from a light source is linearly passed through this sensor through an optical fiber for transmission. In an optical current measuring device for measuring the current flowing in the conductor by detecting the light emitted from the sensor, which is incident as polarized light, and obtaining the rotation angle with respect to the polarization plane of the linearly polarized light proportional to the magnetic field generated from the conductor. An optical current measuring device, wherein at least one of a heating device such as a heater and an electronic cooling device is arranged in the vicinity of the sensor.