JP2014021020A - Optical current transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical current transformer which prevents an optical fiber from being damaged and is excellent in insulation.SOLUTION: In an optical current transformer O including a sensor section 1 which has a container 1a for storing an optical fiber F to be wound around a measured conductor C, a tubular member 2 which is insulating and is connected to the sensor section 1, and an installation section 3 having an installation base 3a for the tubular member 2: the container 1a contains a conductive member; the optical fiber F of the sensor section 1 has a conductive layer 4 in part of its circumference and is bridged to the installation section 3 via a hollow inside of the tubular member 2; and the conductive layer 4 is electrically connected to the conductive member 4 of the container 1a.

Description

  Embodiments described herein relate generally to an optical current transformer using an optical fiber as a sensor.

  A current transformer comprising a magnetic flux detection / reverse magnetic flux compensation circuit device using an electronic circuit is applied to measure the voltage and current of long-distance power transmission and cable power transmission. Since the electric wire or the like to be measured is provided in the sky away from the ground for insulation, the current transformer is provided with a closed magnetic core at the head, and a reverse magnetic flux induction coil is wound around the closed magnetic core.

  Such magnetic cores and reverse magnetic flux induction coils are heavy, and therefore the weight of the head of the current transformer becomes heavy and the earthquake resistance is poor. Since the magnetic core generates heat due to iron loss, filling the tubular member that supports the head of the current transformer with insulating oil also made the head of the current transformer heavier. In addition, it is necessary to provide a conservator for relaxing the thermal expansion of the insulating oil on the head, and the head of the current transformer is further increased in weight and also has an economical problem. Furthermore, in the case of a high-voltage electric line or the like, since a magnetic core is disposed in the vicinity of the high-voltage portion, a high-level insulation technique is required.

JP 2001-112125 A

  Therefore, an optical current transformer using a magneto-optical conversion mechanism that utilizes the Faraday effect in optical fibers has attracted attention. Since the optical current transformer uses an optical fiber instead of a magnetic core, the head of the current transformer can be reduced in weight, and since there is little heat generation, it is not necessary to cool with an insulating oil having a large heat capacity. Furthermore, since the optical fiber itself has insulation performance, the insulation mechanism can be simplified.

  In such an optical current transformer, an optical fiber is disposed inside a metal member at the head, and is wound around an electric wire or the like to be measured. Since the optical fiber passes through the inside of the tubular member that supports the head and is bridged to the installation portion provided on the ground, it is necessary to dispose the optical fiber through the metal member of the head.

  However, since optical fibers are vulnerable to impact and easily break, repeated contact and detachment of optical fibers and metal members due to external vibrations or electrical vibrations caused by energization can cause damage to optical fibers and cause small discharges. As a result, the optical fiber is electrically eroded. Therefore, it is necessary to fix the optical fiber to the metal member. However, if the electrical triple point is constituted by the metal member, the optical fiber, and the insulating medium around the optical fiber by the fixing, the electric field is distorted and the weak point on the insulation. It becomes.

  The embodiment of the present invention has been proposed in order to solve the above-described problems of the prior art. The object is to provide an optical current transformer excellent in insulation without causing damage to the optical fiber.

  An optical current transformer according to an embodiment for achieving the object as described above includes a sensor unit having a container for housing an optical fiber wound around a conductor to be measured, and an insulating property connected to the sensor unit. In the optical current transformer comprising a tubular member having a tubular member and an installation part having an installation base for the tubular member, the container of the sensor part includes a conductive member, and the optical fiber of the sensor part is on a part of the outer periphery. It has a conductive layer, is bridge | crosslinked to the said installation part through the hollow inside of the said tubular member, The said conductive layer is electrically connected with the conductive member of the said container, It is characterized by the above-mentioned.

It is a schematic diagram which shows what simplified the whole structure of the optical current transformer of embodiment. It is sectional drawing which shows the metal member and optical fiber by the side of a sensor part in the optical current transformer of 1st Embodiment. It is sectional drawing which shows the metal member and optical fiber by the side of a sensor part in the optical current transformer of 2nd Embodiment. It is sectional drawing which shows the metal member and optical fiber by the side of a sensor part in the optical current transformer of 3rd Embodiment. It is sectional drawing which shows the metal member and optical fiber by the side of a sensor part in the optical current transformer of 4th Embodiment.

A first embodiment of the present invention will be described below with reference to the drawings.
[1. First Embodiment]
[1.1 Configuration]
The overall configuration of the optical current transformer of this embodiment will be described with reference to FIG. That is, as shown in FIG. 1, the optical current transformer O includes a sensor unit 1, a tubular member 2, and an installation unit 3. The sensor unit 1 has a container 1a that houses an optical fiber F wound around a conductor to be measured. The tubular member 2 has an insulating property and is connected to the sensor unit 1. The installation unit 3 has an installation table 3 a for the tubular member 2.

  The container 1a and the installation base 3a each include a conductive member. The container 1a and the installation base 3a may be entirely composed of a conductive member such as metal, or may be partially provided with a conductive member.

  The optical fiber F of the sensor unit 1 has a conductive layer 4 on a part of the outer periphery (see FIG. 2), and the portion having the conductive layer 4 is electrically connected to the conductive member of the container 1a. The optical fiber F of the sensor unit 1 is bridged to the installation unit 3 through the hollow interior of the tubular member 2 and connected to a signal processing unit (not shown). In addition, in the installation part 3, the conductive layer 4 may further be provided in a part of the outer periphery of the optical fiber F, and the part having the conductive layer 4 may be electrically connected to the conductive member of the installation table 3a.

  The conductive member in the present embodiment includes a metal member M1 provided facing the hollow of the tubular member. Hereinafter, the metal member M1 and the optical fiber F in the sensor unit 1 according to the present embodiment will be described in detail. In addition, the metal member M1 and the optical fiber F having the following configuration may be provided on the installation base 3a of the installation unit 3 in the same manner as the metal member M2 and the optical fiber F. In FIG. 2, the metal member M1 and the optical fiber F on the sensor unit 1 side are illustrated, but the figure is turned upside down, and the sensor unit 1 side in the drawing is set as the installation unit 3 side, whereby the metal member M2 on the installation unit 3 side. And the optical fiber F.

  The optical fiber F passes through the metal member M1 and is introduced into the hollow interior of the tubular member 2. As shown in FIG. 2, a concave portion 5 having an inner diameter larger than the outer diameter of the portion of the optical fiber F having the conductive layer 4 is provided on the tubular member 2 side of the metal member M1.

Moreover, the upper part of the inner peripheral surface of the recessed part 5 has the curved part 6 processed into circular arc shape. The curved portion 6 can be formed by, for example, subjecting the upper corner of the inner peripheral surface of the recess 5 to fillet processing and rounding the corner. The curved portion 6 only needs to be processed into an arc shape that can remove the corner where the electric field concentrates, and the shape may not be a perfect circle.

  A through hole 7 having an inner diameter larger than the outer diameter of the portion of the optical fiber F having the conductive layer 4 is provided in a part of the bottom surface of the recess 5. Further, the inner diameter of the through hole 7 is smaller than the inner diameter of the recess 5. It is preferable that the through hole 7 is provided at the center of the bottom surface of the recess 5 and the cross section of the recess 5 is formed symmetrically.

  An optical fiber F is inserted through the through hole 7. A conductive layer 4 is provided around a part of the optical fiber F according to the present embodiment. The conductive layer 4 can be provided with a conductive material such as carbon, silver powder, or aluminum by a technique such as dipping, coating, vapor deposition, or electrolytic plating. The conductive layer 4 may be formed on the coating of the optical fiber F or may be formed on the core of the optical fiber F.

  The optical fiber F is inserted through the through hole 7 so that the portion having the conductive layer 4 is located in the through hole 7 of the metal member M1. At this time, the conductive layer 4 is inserted so as not to contact the through hole 7. The optical fiber F located on the sensor unit 1 side is also covered with the conductive layer 4. On the other hand, the optical fiber F located on the tubular member 2 side does not have the conductive layer 4.

  The optical fiber F having the conductive layer 4 located on the sensor unit 1 side is fixed to the conductive member of the container 1a. Thereby, the conductive layer 4 of the optical fiber F and the conductive member of the container 1a are electrically connected. The conductive member to which the optical fiber F is fixed may be any conductive member as long as it is included in the container 1a. However, it is preferable to select the fixing position so that the conductive layer 4 of the optical fiber F does not contact the through hole 7.

[1.2 Action]
The operation of the present embodiment having the above configuration will be described below. As shown in FIG. 1, the optical fiber F of the sensor unit 1 detects a current such as a high-voltage electric line. At this time, the conductive member included in the sensor unit 1 is also at a high voltage. The conductive layer 4 of the optical fiber F is electrically connected to a conductive member included in the container 1 a of the sensor unit 1. Therefore, the conductive layer 4 has the same potential as the metal member M1 included in the conductive member. That is, the potentials are equal as shown by the equipotential lines in FIG.

  For this reason, the DC electric field at the contact point between the conductive layer 4 and the metal member M1 is relaxed, and a high electric field does not occur. Moreover, since the upper part of the inner peripheral surface of the recessed part 5 is processed into the circular arc shape, the applied AC component is shielded by the metal member M <b> 1, and the electric field at the tip of the conductive layer 4 is relaxed.

  Further, since the inner diameter of the through hole 7 is larger than the portion of the optical fiber F having the conductive layer 4, even if the optical fiber F is shaken due to external vibration or the like, the optical fiber F The metal member M1 is contacted through the conductive layer 4.

[1.3 Effect]
The effects of the present embodiment as described above are as follows.
(1) Since the optical fiber F is brought into contact with the conductive member contained in the container 1a through the conductive layer 4, the electrical triple point is constituted by the conductive member, the optical fiber F, and the insulating medium around the optical fiber F. Insulating properties can be improved.
(2) Since the electric field is relaxed, the vibration of the optical fiber F due to electrical vibration can be prevented.
(3) Since the conductive layer 4 and the metal member M1 have the same potential and the direct current electric field is relaxed and no micro discharge is generated, electrical erosion of the optical fiber F can be prevented.
(4) Since the optical fiber F is in contact with the metal member M1 through the conductive layer 4 even if external vibration or the like occurs, the optical fiber F is prevented from being damaged due to repeated contact and separation with the metal member M1. be able to.
(5) Although the optical fiber F is easily damaged by an external force, when the optical fiber F is fixed to the conductive member of the container 1a, the portion having the conductive layer 4 can be fixed. Damage can be prevented.

(6) Furthermore, an electric field corresponding to the length of the optical fiber F is generated in the installation part 3, but the installation part 3 is also provided with the same configuration as the sensor part 1, so that the above (1) to ( The effect 5) can be obtained.

[2. Second Embodiment]
[2-1. Constitution]
FIG. 3 shows a cross-sectional view of the metal member M1 and the optical fiber F on the sensor unit 1 side in the optical current transformer O according to the second embodiment of the present invention. This embodiment is basically the same as the first embodiment. Accordingly, the same parts as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  In the metal member M1 in the present embodiment, a first recess 8 is provided on the tubular member 2 side, and a second recess 9 is provided coaxially on the surface opposite to the surface on the tubular member 2 side. The inner diameter of the first recess 8 is smaller than the inner diameter of the second recess 9. The inner diameter of the first recess 8 is preferably about 1 mm to 10 mm larger than the outer diameter of the portion of the optical fiber F having the conductive layer 4.

  The through-hole 7 of this embodiment is provided so that the bottom surfaces of the first recess 8 and the second recess 9 partially communicate with each other. The inner diameter of the through hole 7 is smaller than the inner diameters of both concave portions. It is preferable that the through-hole 7 communicates the centers of the bottom surfaces of both concave portions, and the cross sections of both concave portions are formed symmetrically.

  The inner diameter of the through hole 7 is substantially the same as the diameter of the portion of the optical fiber F having the conductive layer 4. That is, it is processed so that the portion of the optical fiber F having the conductive layer 4 can be inserted and the optical fiber F can be fixed. Therefore, when the optical fiber F is inserted through the through hole 7, the optical fiber F is fixed to the through hole 7 of the metal member M1 and is electrically connected to the metal member M1.

  The conductive layer 4 of the optical fiber F is provided so as not to protrude from the first recess 8. That is, the tip of the conductive layer 4 on the tubular member 2 side is located on the plane extension line of the upper surface of the first recess 8 or on the inner side of the plane extension line.

[2-2. Action]
The operation of the present embodiment as described above will be described below. The potential is gentle compared to the first embodiment as shown by the equipotential lines in FIG. Since the peripheral surface of the conductive layer 4 and the inner peripheral surface of the first recess 8 are close to each other, and the tip of the conductive layer 4 does not protrude from the first recess 8, the applied high voltage AC component is the metal member M1. Shielded by. With this configuration, the direct current component is also relaxed, and a large electric field is not generated at the tip of the conductive layer 4.

  Further, since the inner diameter of the through hole 7 is substantially coincident with the portion of the optical fiber F having the conductive layer 4 and the optical fiber F is fixed by the metal member M1 through the conductive layer 4, the conductive layer 4 is made of metal. It has the same potential as the member M1.

[2-3. effect]
According to the present embodiment as described above, the following effects can be obtained in addition to the first embodiment.
(1) Since the peripheral surface of the conductive layer 4 and the inner peripheral surface of the first recess 8 are close to each other, the electric field is further reduced as compared with the first embodiment, and electrical erosion of the optical fiber F is prevented. be able to.
(2) Since the tip of the conductive layer 4 does not protrude from the first recess 8, even if the conductive layer 4 other than the fixed portion is in contact with the metal member M 1, there is no charge transfer, so that the minute Discharge does not occur and electrical erosion can be prevented.

[3. Third Embodiment]
[3-1. Constitution]
FIG. 4 is a sectional view of the conductive member D1 and the optical fiber F on the sensor unit 1 side in the optical current transformer O according to the third embodiment of the present invention. This embodiment is basically the same as the first embodiment. Accordingly, the same parts as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The optical fiber F in this embodiment is fixed to a conductive member D1 included in the container 1a. The conductive member D1 may be processed to fix the optical fiber F, or an existing conductive member may be used for the container 1a. Further, in order to introduce the optical fiber F into the tubular member 2, a through hole may be provided in a part of the conductive member of the container 1a, or an existing hole may be used.

  A portion of the optical fiber F having the conductive layer 4 is fixed to the conductive member D1 by a fixture 10. The fixture 10 of the present embodiment is made of metal, and is stressed so as to be wound toward the conductive member D1 side. One end (not shown) of the fixture 10 is fixed to the conductive member D1 with a screw or a bolt. The fixture 10 may be one that does not have stress and fixes both ends with screws or bolts. However, since the optical fiber F is often thin, the fixture that can sufficiently fix the optical fiber F to the conductive member D1. 10 is used.

  The portion of the optical fiber F having the conductive layer 4 is fixed to the conductive member D <b> 1 by the stress of the fixture 10. At this time, the fixture 10, the conductive layer 4, and the conductive member D1 come into contact with each other, and the conductive layer 4 of the optical fiber F is electrically connected to the conductive member D1.

  In addition, the conductive member D1 used for fixing the optical fiber F may be provided with a notch 11 so that the conductive member 4 does not come into contact with the end of the conductive layer 4 on the tubular member 2 side. The gap between the conductive member D1 provided by the notch 11 and the peripheral surface of the conductive layer 4 on the tubular member 2 side is preferably 1 mm to 10 mm.

[3-2. Action]
The operation of the present embodiment as described above will be described below. Since the conductive layer 4 of the optical fiber F is electrically connected to the conductive member D1 of the container 1a by the metal fixture 10, the conductive layer 4 has the same potential as the conductive member D1 and a high electric field is generated. Absent. Moreover, since the peripheral surface of the conductive layer 4 on the tubular member 2 side and the conductive member D1 can be brought close to each other by providing the notch portion 11, the electric field at the tip of the conductive layer 4 is suppressed.

[3-3. effect]
According to the present embodiment as described above, the following effects can be obtained in addition to the first embodiment.
(1) By providing the notch 11, the peripheral surface of the conductive layer 4 on the tubular member 2 side and the conductive member D1 are close to each other, so that the electric field is relaxed and electrical erosion of the optical fiber F is prevented. Can do.
(2) The electric field of the optical fiber F can be prevented because the electric field of the fixture 10, the optical fiber F, and the conductive member D1 is suppressed and no micro discharge occurs.

[4. Fourth Embodiment]
[4-1. Constitution]
FIG. 5 shows a cross-sectional view of the conductive member D1 and the optical fiber F on the sensor unit 1 side in the optical current transformer O according to the fourth embodiment of the present invention. This embodiment is basically the same as the first embodiment. Accordingly, the same parts as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The optical fiber F in the present embodiment is fixed to a conductive member D1 included in the sensor unit 1. The conductive member D1 may be processed to fix the optical fiber F, or an existing conductive member may be used for the sensor unit 1. Further, in order to introduce the optical fiber F into the tubular member 2, a through hole may be provided in a part of the conductive member of the container 1a, or an existing hole may be used.

  The portion of the optical fiber F having the conductive layer 4 is supported by the conductive member D <b> 1 via the pulley 12 by being bent along the pulley 12. The pulley 12 of the present embodiment is a metal rotatable member, and is preferably provided with a groove having a width that can hold the portion of the optical fiber F having the conductive layer 4. Therefore, the conductive layer 4 is supported by the conductive member D1 via the pulley 12, and the pulley 12, the conductive layer 4, and the conductive member D1 are electrically connected.

  The pulley 12 of this embodiment may be supported by the conductive member D <b> 1 via the tension applying means 13. The tension applying means 13 is made of metal and uses a spring or the like. The tension applying means 13 applies mechanical tension to the pulley 12 and rotates the pulley 12. Then, tension is applied to the optical fiber F so as to have a natural frequency sufficiently separated from the frequency of the high-frequency component included in the length of the optical fiber F and the applied high voltage. When the tension applying means 13 is provided, the conductive layer 4 is electrically connected to the conductive member D1 through the pulley 12 and the tension applying means 13.

[4-2. Action]
The operation of the present embodiment as described above will be described below. Since the conductive layer 4 of the optical fiber F is electrically connected to the conductive member D1 of the container 1a via the pulley 12 and the tension applying means 13, the conductive layer 4 has the same potential as the conductive member D1 and has a high electric field. Will not occur. Further, the pulley 12 is rotated by the tension applying means 13.

[4-3. effect]
According to the present embodiment as described above, the following effects can be obtained in addition to the first embodiment.
(1) Since the optical fiber F is supported by the pulley 12 so that the optical fiber F loosened due to thermal expansion does not repeat contact and detachment with the conductive member of the container 1a due to vibration, and thus no micro discharge occurs. It is possible to prevent electrical erosion of F.
(2) Further, by rotating the pulley 12, the change in tension due to thermal expansion and the change in the length of the optical fiber F can be absorbed, and the bending radius of the optical fiber F can be maintained. Disappears.
(3) Furthermore, since an appropriate tension can be applied to the pulley 12 by providing the tension applying means 13, the optical fiber F does not vibrate due to the electromagnetic mechanical force, and the change of the optical attenuation factor is not caused. Measurement error is reduced.
(4) The applied magnetic field changes if the length of the optical fiber F changes due to thermal expansion, but by applying tension, the length of the optical fiber F to which the magnetic field is applied can be kept constant, thus reducing measurement errors. To do.
(5) Although the length of the normal optical fiber F changes due to thermal expansion inside the tubular member 2, the length of the changed optical fiber F can be accommodated in the magnetic shield by providing the pulley 12 in the sensor unit 1. In contrast, the magnetic field of the high voltage circuit does not act.

[Other Embodiments]
(1) The optical current transformer of the embodiment is not limited to the illustrated one. The optical current transformer may be a reflection type using a mirror, a one-way type without a mirror, or an interference type fiber type optical current transformer. That is, the present invention is characterized by the optical fiber F and the metal member M, and the other detailed configurations can be selected as appropriate.

  (2) Each embodiment is not independent and can be combined suitably. That is, in consideration of the thermal expansion of the optical fiber F, for example, the sensor unit 1 side may be configured in the fourth embodiment, and the installation unit side may be configured in the second embodiment. It goes without saying that by configuring the embodiments in combination, the functions and effects of the applied embodiments can be achieved together.

  (3) The shape of each component of the metal member M1 and the conductive member D1 can be selected as appropriate. For example, various shapes such as a circle, an ellipse, or a square can be selected as the shape of each recess or through-hole 7.

  (4) Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

O ... Optical current transformer C ... Measuring conductor F ... Optical fiber M1, M2 ... Metal member D1 ... Conductive member 1 ... Sensor part 1a ... Container 2 ... Tubular member 3 ... Installation part 3a ... Installation base 4 ... Conductive layer 5 ... Concave 6 ... curved portion 7 ... through hole 8 ... first recess 9 ... second recess 10 ... fixture 11 ... notch 12 ... pulley 13 ... tension applying means

Claims (11)

A sensor unit having a container for storing an optical fiber wound around the conductor to be measured; an insulating tubular member connected to the sensor unit; and an installation unit having an installation base for the tubular member. In the optical current transformer
The container of the sensor unit includes a conductive member,
The optical fiber of the sensor part has a conductive layer on a part of the outer periphery, and is bridged to the installation part through the hollow interior of the tubular member,
The photocurrent transformer, wherein the conductive layer is electrically connected to a conductive member of the container. The installation base includes a conductive member,
The optical fiber further has a conductive layer on a part of the outer periphery on the installation part side,
The optical current transformer according to claim 1, wherein the conductive layer is electrically connected to a conductive member of the installation base. The conductive member includes a metal member provided facing the hollow of the tubular member,
The through hole through which the part which has the conductive layer of the said optical fiber is penetrated is provided in the said metal member at the bottom face of the recessed part provided in the said tubular member side, The 1 or 2 characterized by the above-mentioned. Light current transformer. The conductive member includes a metal member provided facing the hollow of the tubular member,
The metal member is coaxially provided with a first recess on the surface on the tubular member side and a second recess on a surface opposite to the surface on the tubular member side,
The through-hole through which the part which has a conductive layer of the said optical fiber is penetrated is provided, and the bottom face of said 1st recessed part and the bottom face of said 2nd recessed part are provided. Light current transformer.   The optical current transformer according to claim 3 or 4, wherein a portion having a conductive layer of an optical fiber inserted through the through hole is fixed by the metal member in the through hole.   The optical current transformer according to claim 3 or 4, wherein the conductive layer is provided so as not to protrude from the concave portion on the tubular member side.   The optical current transformer according to any one of claims 2 to 6, wherein an upper portion of an inner peripheral surface of the concave portion on the tubular member side is processed into an arc shape.   The said optical fiber is being fixed to the said electrically-conductive member by making the said electrically-conductive member hold | maintain the part which has the electrically conductive layer of the said optical fiber with a metal fixture. Light current transformer.   9. The light according to claim 8, wherein the conductive member to which the optical fiber is fixed is provided with a notch so that the conductive member does not come into contact with the end of the conductive layer on the tubular member side. Current transformer.   3. The optical fiber is supported by the conductive member by bringing a portion of the optical fiber having a conductive layer into contact with a metal pulley provided on the conductive member. The described light current transformer. The optical current transformer according to claim 10, wherein the metal pulley is provided with tension applying means.