JP2017091815A - Insulator type optical current transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insulator type optical current transformer good in assemblability, inexpensive and also high in reliability.SOLUTION: Provided is an insulator type optical current transformer comprising: a first metal container; a second metal container; and a hollow porcelain tube. The first metal container stores: a metal conductor through which electric current passes; and an optical current sensor of measuring the electric current flowing through the metal conductor and transforming the same into an optical signal, and the lower part of the container is provided with a first hole for inserting an optical fiber wire for optical signal transformation drawn from the optical current sensor. The second metal container is arranged at a grounding part, and the upper part of the container is provided with a second hole for inserting the optical fiber wire so as to face the first hole. The porcelain tube is arranged in such a manne that the first metal container is arranged at the upper part, the second metal container is arranged at the lower part, and the mutual metal containers are connected. The optical fiber wire is drawn out from the optical current sensor, is inserted into the first hole of the first metal container and the second hole of the second metal container, and is arranged so as to linearly sag at almost the central part of the inside of the porcelain tube.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to an insulator type optical current transformer.

  As an apparatus for measuring a current flowing through a high-voltage conductor, an insulator type current transformer that uses, for example, oil or SF6 gas as an insulating material is generally used.

  Recently, photocurrent sensors that apply the Faraday effect are small and lightweight, so that optical current transformers that apply them have been commercialized.

  In this type of optical current transformer, signals are transmitted using an optical fiber line. However, since glass, which is a member of the optical fiber line, is an insulating material, it is easy to ensure insulation, and a photocurrent with a built-in Faraday element. It is possible to install the sensor at a high voltage portion where a conductor is disposed.

  On the other hand, since an optical fiber wire is stretched thinly, it is easily broken when an excessive force is applied, and therefore, it is necessary to handle it with great care.

  In particular, the soot tube vibrates and deforms due to the electromagnetic force associated with a large current generated during an accident such as a short circuit in an electrical system to which an earthquake or high-voltage conductor is connected, and an excessive force is applied to the optical fiber line or the optical fiber line is bent. The optical fiber line breaks and the light amount is lost.

  Further, since the optical fiber lines are entangled when the optical fiber line is not fixed, an optical fiber built-in insulator having a structure in which the optical fiber line is embedded and passed through the tube wall of the soot tube has been developed.

Japanese Patent Laid-Open No. 06-325648

  In the case of the insulator structure described in the above document, the loss of light quantity does not occur due to the spiral arrangement of the optical fiber line along the side surface of the optical pipe or the stress due to bending in order to prevent the optical fiber line from being broken by bending. There is a problem that the manufacturing is complicated and expensive, such as injecting silicone grease into the inside of the soot tube. Further, when the voltage of the conductor through which the current flows becomes higher, the size of the soot tube becomes larger and longer, and there are also problems such as difficulty in manufacturing and cost.

  The problem to be solved by the present invention is to provide an insulator type optical current transformer which is easy to assemble, is inexpensive and has high reliability.

  The insulator type optical current transformer of the embodiment has a first metal container, a second metal container, and a hollow soot tube. The first metal container accommodates a metal conductor through which a current flows and a photocurrent sensor that measures the current flowing through the metal conductor and converts it into an optical signal, and is used for transmitting an optical signal drawn from the photocurrent sensor at the bottom of the container. A first hole for inserting the optical fiber line is provided. The second metal container is disposed at the grounding portion, and a second hole for inserting the optical fiber line is provided in the upper part of the container so as to face the first hole. The soot tube is disposed so that the first metal container is disposed on the upper side and the second metal container is disposed on the lower side, and the metal containers are connected to each other. The optical fiber line is drawn out from the photocurrent sensor, inserted through the first hole of the first metal container and the second hole of the second metal container, and arranged so as to hang down substantially at the center of the soot tube. Has been.

It is a whole block diagram of the insulator type optical current transformer which shows the 1st Example of this invention. FIG. 2 is a detailed view of a high voltage unit in FIG. 1. FIG. 2 is a detailed view of a ground potential portion in FIG. 1. FIG. 2 is a detailed view of a potential fixing member (high voltage part side) in FIG. 1. FIG. 2 is a detailed view of a positioning structure of an optical fiber core wire on the ground potential portion side in FIG. 1. FIG. 6 is a perspective view of FIG. 5. FIG. 2 is a detailed view of a potential fixing member (ground potential portion side) in FIG. 1. FIG. 8 is a perspective view of FIG. 7. It is a figure which shows the relationship between the electric potential of an insulator type optical current transformer, and the length of an optical fiber core wire.

Hereinafter, an insulator type optical current transformer according to one embodiment will be described with reference to the drawings.
As shown in FIG. 1, the insulator type optical current transformer of this embodiment includes a metal container 2 as a first metal container disposed on the high voltage part side (upper side) and a ground potential part side (lower side). ) Arranged as a second metal container, and a hollow soot tube 4 disposed (standing) with the axis in the vertical direction so as to connect the metal containers 2 and 5 to each other, And an optical fiber core wire 6 as an optical fiber wire arranged so as to hang down linearly at a substantially central portion in the rod tube 4.

  The soot tube 4 is disposed so that the metal container 2 is disposed on the upper side and the metal container 5 is disposed on the lower side, and the metal containers 2 and 5 are connected to each other.

  Silicone grease or the like is not injected into the inside of the metal containers 2 and 5 and the soot tube 4, and a gas (insulating gas) such as SF6 gas, nitrogen gas, dry air, or air is filled as necessary. In this example, the metal containers 2 and 5 and the soot tube 4 are filled with SF6 gas.

  As shown in FIG. 2, the bottom portion of the metal container 2 is an opening, and a container lower plate 2a is attached to the opening and sealed. A hole 11 is provided in the container lower plate 2a as a first hole for inserting the optical fiber core wire 6 to the side of the tub tube 4 side.

  The inner peripheral surface of the hole 11 has a surface roughness, for example, a roughness finer than 25S (JIS standard) so that the optical fiber core wire 6 can move smoothly. In addition to simply providing the holes 11 in the container lower plate 2 a, an insulating material having good slidability, for example, an annular member (O-ring) made of fluororesin may be provided at the edge of the holes 11.

  Note that 25S (JIS standard) is a “25S” roughness classification in the “surface roughness classification” of JIS B 0601: 1990 Rmax. A roughness finer than 25S (JIS standard) is, for example, “12. 5S "," 6.3S "," 3.2S "," 1.6S "," 0.8S ", etc. “12.5S” is a medium-grade machine-finished surface, and refers to a surface obtained by turning, milling or the like obtained with high-speed appropriate feed and a good tool.

  “6.3S” is a good machine finish surface, and refers to the outer ring outer surface of the rolling bearing, the adhesive surface between the valve and the valve seat, and the outer surface of the hydraulic cylinder ram. The same effect can be obtained by forming the member (in this case, the container lower plate 2a) itself or a portion around the hole 11 with an insulating material such as a fluororesin instead of a metal.

  The metal container 2 houses a conductor 1 as a metal conductor through which a current flows, a photocurrent sensor 3 for measuring a current flowing through the conductor 1, and a potential fixing member 12 as a first potential fixing member.

  The photocurrent sensor 3 is a sensor that measures the current flowing through the conductor 1 using the Faraday effect and converts it into an optical signal, and is provided with at least one. In this example, three photocurrent sensors 3 are provided for the main system, the sub system, and the standby system.

  For this reason, a plurality of holes 11 (see FIG. 3) and holes 21 (see FIG. 5) are arranged at a certain interval in the vicinity of the axis of the tub tube 4 so as to pass the optical fiber core wires 6 for a plurality of systems, respectively. .

  An optical fiber core wire 6 is drawn out from the photocurrent sensor 3, and an optical signal as a current measurement result is transmitted by the optical fiber core wire 6.

  The three optical fiber core wires 6 drawn out from the respective photocurrent sensors 3 are fixed (adhered) to the potential fixing member 12 and then inserted into the holes 11 of the container lower plate 2a of the metal container 2 so that Is inserted into a hole 21 of a core wire positioning member 9 fixed to a lid 8 (a container upper plate) attached so as to block the opening 7 at the upper part of the metal container 5 so as to hang linearly at the center of (See FIGS. 2 and 4).

  That is, the optical fiber core wire 6 for transmitting a signal is connected to the photocurrent sensor 3 disposed in the metal container 2 of the high voltage portion, passes through the vicinity of the center of the soot tube 4, and is disposed in the ground potential portion. It is wired to enter 5.

  As shown in FIG. 3, the potential fixing member 12 is a metal ring-shaped member having an inclined surface 12a inclined so as to fall inward, and the center portion is opened so that the hole 11 of the container lower plate 2a is exposed. Has been. Since the potential fixing member 12 is made of metal, it has the same potential as the high voltage portion.

  The three optical fiber core wires 6 are bonded and fixed to the inclined surface 12a of the potential fixing member 12 by the silicone adhesive 13, respectively, and then inserted into the holes 11 provided in the container lower plate 2a.

  As shown in FIG. 4, in the metal container 5, a lid 8 disposed so as to close the opening 7 provided in the upper part (upper surface) of the metal container 5, and a substantially central portion of the lid 8 are provided. An opening 8a (see FIG. 6) and a potential fixing member 22 as a second potential fixing member fixed to the lower surface of the lid 8 avoiding the opening 8a are accommodated.

  In the metal container 5, the optical fiber core wire 6 inserted into the metal container 5 through the tub tube 4 is provided with a slack 6 a (extra length portion) and fixed (fixed) to the potential fixing member 22 with the silicone adhesive 13. The fiber core wire 6 is wired downward. Since the silicone adhesive 13 has a low hardness even after curing, it can flexibly cope with the movement and expansion / contraction of the optical fiber core wire 6.

  On the upper surface of the metal container 5 connected to the soot tube 4, a hole 21 is disposed at a position almost directly below the upper hole 11. That is, on the upper surface of the metal container 5, a hole 21 for inserting the optical fiber core wire 6 is provided in the upper part of the container so as to face the hole 11.

  The optical fiber core wire 6 enters the metal container 5 from the soot tube 4 through the hole 21. At this time, the same number of holes 11 and holes 21 as the number of the optical fiber core wires 6 are prepared, and one set (a pair) is formed vertically, and one optical fiber core wire 6 is passed through one set (a pair). In other words, the plurality of optical fiber core wires 6 are not passed through one set of holes.

  The surface of the hole 21 on the ground voltage portion side also has a surface roughness finer than 25S (JIS standard) so that the optical fiber core wire can move smoothly. As a constituent member of the hole 21 on the upper surface of the metal container 5, an insulating material such as an annular member (O-ring) made of a fluororesin having good slidability may be used similarly to the above-described high voltage portion.

  In this embodiment, the core wire positioning member 9 using a fluororesin is disposed in the vicinity of the center of the upper surface of the metal container 5 as a member for providing the hole 21.

  As shown in FIGS. 5 and 6, a positioning structure for positioning the optical fiber core wire 6 is formed on the upper portion of the metal container 5 by a lid 8, a core wire positioning member 9, a pressing member 10, a screw 31, and the like.

  The core wire positioning member 9 is a disk-shaped member, and is provided with three holes 21 for inserting the optical fiber core wire 6 and four screw holes 9a for screw tightening near the center. The pressing member 10 is a ring-shaped member and has a screw hole 31 corresponding to the screw hole 9a. The holding member 10 is fixed by sandwiching the core wire positioning member 9 between the holding member 10 and the screw 31 from the back surface of the cover 8 by screwing the screw 31 into the screw hole 9 a and the screw hole 31.

  As shown in FIGS. 7 and 8, the potential fixing member 22 has a semi-cylindrical shape (like a gutter) obtained by vertically dividing a metal tube, and is fixed to the lower surface of the lid 8 with a screw or the like. ing.

  The metal container 5 is provided with an opening 7 at the top. A lid 8 is attached to the upper part of the metal container 5 so as to close the opening 7. The lid 8 is provided with a hole substantially at the center, and a core wire positioning member 9 is attached to the hole.

  The core wire positioning member 9 is provided with a hole 21 as a second hole through which the optical fiber core wire 6 is inserted. That is, the metal container 5 is provided with a hole 21 through which the optical fiber core wire 6 is inserted facing the hole 11 of the upper metal container 2.

  The holes 11 and 21 are arranged so as to be scattered at a position away from the center of the soot tube 4 by a certain distance. As a specific example, three are provided at intervals of 120 degrees.

  In the metal container 5, the optical fiber core wire 6 is wired with a certain slack 6a (extra length portion). In addition, a metal potential fixing member 22 having the same potential as the ground potential portion is disposed inside the metal container 5 in the hole 11. The optical fiber core wire 6 is bonded and fixed to the potential fixing member 22 so as to be electrically at the same potential. As an adhesive for bonding the optical fiber core wire 6, a silicone adhesive 13 which is a silicone-based adhesive having a low hardness even after curing is used.

  As a sag amount prepared inside the metal container 5 from the hole 21, a limit value A is obtained by the following (formula 1), and at least the sag amount is made longer than the limit value A. That is, the limit value A <sag amount.

A = √ (L ² + δ ² ) −L (Equation 1)
δ = F · L ³ / (3 · E · I)
Where L is the length of the tubule
F: Concentrated weight acting on the head of the tubule
E: Young's modulus of tubule
I: Secondary moment of inertia
δ: Displacement of the head of the soot tube
A: Sag amount

  For example, when the composite pipe having a cylinder length of about 4.5 m is adopted as the pipe 4, the following numerical values are obtained.

  When a force acts on the head of the tub tube 4 such as an electromagnetic force when an earthquake force or an accident current flows, the head is displaced and stress is generated at the connection portion between the tub tube 4 and the metal container 5. Is designed and manufactured to withstand these mechanical stresses, but has a tolerance (generally guaranteed by the manufacturer), and this force is F (concentrated load acting on the head of the duct) And

As a result, A = 7.88 × 10 ⁻³ [m].
Therefore, the sag amount A is set to 8 mm or more.

The insulator type optical current transformer configured as described above operates as follows.
Since the hole 21 through which the optical fiber core wire 6 on the top surface of the metal container 5 is passed is disposed directly below the hole 11 through which the optical fiber core wire 6 is passed through the bottom surface of the metal container 2, the optical fiber core wire 6 is linearly disposed. Can do. Therefore, the optical fiber core wire can be easily arranged, a complicated manufacturing process is not required, and the manufacturing cost can be reduced.

  Further, silicone grease or the like is not injected into the inside of the soot tube 4 and the metal container 5, and the periphery of the optical fiber core wire 6 in the soot tube 4 becomes a gas. Accordingly, there is no action of force and generation of stress accompanying the contact with the surrounding members on the optical fiber core wire 6, so that stable quality can be ensured. Of course, silicone grease or the like is not injected. For this reason, the manufacturing process is simplified and the cost can be reduced.

  Further, only one optical fiber core wire 6 is provided for one set of holes 11 and 21 for passing through. Therefore, the adjacent optical fiber core wires 6 are not entangled with each other, and there is no breakage due to the optical fiber core wires 6 touching each other.

  When an earthquake or an accident occurs, the head of the soot tube 4 is displaced by the seismic force or electromagnetic force, and the required amount of the optical fiber core wire 6 is drawn into the soot tube 4 from the slack 6a in accordance with the displacement.

  On the other hand, when the slack 6a of the optical fiber core 6 is secured to the minimum required length defined by (Equation 1), excessive force is not applied to the optical fiber core 6 and the optical fiber core 6 is not broken. Absent.

  Further, when the head of the soot tube 4 is displaced, the optical fiber core wire 6 is rubbed with the inserted holes 11 and 21, but the surface roughness of the holes 11 and 21 is finished with a finer roughness than 25S (JIS standard). By smoothing, the surface of the optical fiber core wire 6 is not damaged or broken.

  Here, with reference to FIG. 9, the relationship between the potential and the length of the optical fiber core wire 6 when the insulator type optical current transformer is used in a system having a high DC voltage such as DC power transmission will be described.

  When an insulator type optical current transformer is used in a system having a DC high voltage, the potential is determined by the resistance value because the optical fiber core wire 6 is an insulator. The resistivity of the optical fiber core wire 6 is uniform, L: the length of the optical fiber core wire 6 between two points where the potential is fixed, V1: the potential at the position of the hole 11 of the metal container 2 of the optical fiber core wire 6, V2: potential at the position of the hole 21 of the metal container 5 of the optical fiber core wire 6, L1: length of the optical fiber core wire 6 from the photocurrent sensor 3 to the position of the hole 11 of the metal container 2, L2: of the metal container 5 If the length of the optical fiber core wire 6 from the position of the hole 21 to the ground potential point,

V1 = (L−L1) × V / L
V2 = L2 × V / L
However, as specific values, L = 4.5 m L1 = 0.2 m L2 = 0.3 m V = 250 kV
Substituting
V1 = 239kV
V2 = 17kV
It becomes.

  Usually, the potential of the optical fiber core wire 6 at the edge of the hole 11 of the metal container 2 is 239 kV, the potential of the metal container lower plate 2 a itself provided with the hole 11 is 250 kV, and a differential voltage of 11 kV is generated.

  In the wiring condition of the optical fiber core wire 6, although the optical fiber core wire 6 approaches the hole 11, a state such as a minute gap that does not contact the metal container lower plate 2 a continues, and the optical fiber is caused by partial discharge or dielectric breakdown. The core wire 6 may be damaged or broken.

  Therefore, in this embodiment, a potential fixing member 12 having the same potential as that of the metal container 2 is disposed in the vicinity (upper part) of the hole 11 and the optical fiber core wire 6 is bonded to the potential fixing member 12 to forcibly contact them. And getting an electrical connection.

  For this reason, no differential voltage is generated in the optical fiber core wire 6 at the hole 11, and the fiber core wire 6 is not broken by causing partial discharge or dielectric breakdown.

  On the other hand, on the ground potential portion side, the optical fiber core wire 6 is provided with a sag 6a, and is fixed to the potential fixing member 22 to secure a constant sag amount A, and the potential is fixed to the same potential as the ground potential. It pulls out downward through the member 22.

  At this time, the potential of the optical fiber core wire 6 at the position of the hole 21 of the metal container 5 is 17 kV and the potential of the core wire positioning member 9 provided with the hole 21 is 0 kV (ground potential). Occur.

  When the optical fiber core wire 6 is simply passed through the hole 21, the optical fiber core wire 6 approaches the hole 21, but a state like a minute gap that does not contact the edge of the hole 21 continues, and partial discharge or There is a possibility that the optical fiber core wire 6 may be broken or broken due to dielectric breakdown.

  Therefore, in this example, by providing the core wire insertion hole 21 in the upper part of the metal container 5 in the core wire positioning member 9 using an insulating material, a sufficient insulation distance can be secured, causing partial discharge and dielectric breakdown. The optical fiber core wire 6 is not broken. In particular, when the core wire positioning member 9 is a plate-like member whose main component is a fluororesin or the like, it is excellent in slidability, insulation and durability, and insulation and durability can be ensured.

  In addition, about the optical fiber core wire 6, a voltage is loaded also in the creeping direction. Usually, the optical fiber core wire 6 is made of a glass material at a portion through which light as a signal is transmitted, but the outer surface thereof is usually made of acrylic or the like for the purpose of ensuring its strength and preventing scratches on the surface of the glass material. The protective material is coated. Since these protective materials are insulators, they have a dielectric strength in the creeping direction of at least about 10 kV / cm. Therefore, from this value, it is possible to sufficiently ensure the pressure resistance in the creeping direction of the optical fiber core wire 6 in the soot tube 4 and the metal containers 2 and 5.

  Furthermore, since the insulator-type optical current transformer is assumed to be installed outdoors, the temperature of the adhesive fixing part of the optical fiber core wire 6 is considered in consideration of the influence of heat generation or solar radiation due to energization on the outside air temperature. Will be exposed to an environment of -30 degrees C to 70 degrees C.

  In such an installation environment, stress may be applied to the optical fiber core wire 6 due to thermal expansion or contraction of the potential fixing member 22 and the adhesive, resulting in a loss of light quantity and the like, which may deteriorate the light state. In this embodiment, the silicone adhesive 13 having a low hardness after curing is used as the adhesive.

  Thereby, even if there is thermal expansion or thermal contraction, no stress is applied to the optical fiber core wire 6, and the light state such as light loss is not deteriorated.

  Thus, according to this embodiment, the metal container 2 of the high voltage part and the metal container 5 of the ground potential part are arranged one above the other so that the containers 2 and 5 are connected by the hollow tub tube 4. In the constructed insulator type optical current transformer, the optical fiber core wire 6 connected to the photocurrent sensor 3 accommodated in the metal container 2 is inserted into the hole 11 of the metal container 2 and the hole 21 of the metal container 5 and the soot tube. Arrangement is made so as to hang linearly at the substantially central portion in 4, so that it is possible to provide an insulator type optical current transformer that is easy to assemble, inexpensive, and highly reliable.

  Although the embodiment of the present invention has been described, this embodiment is presented as an example and is not intended to limit the scope of the invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  In the above embodiment, the core wire positioning member 9 including the upper hole 21 of the metal container 5 is made of an insulating material such as fluororesin, but the lower hole 11 of the metal container 2 is made of a ring-shaped member made of fluororesin. Alternatively, both or one of the holes 11 and 21 may be an insulating material.

  DESCRIPTION OF SYMBOLS 1 ... Conductor, 2 ... Metal container (high voltage part side), 3 ... Photocurrent sensor, 4 ... Saddle tube, 5 ... Metal container (ground potential part side), 6 ... Optical fiber core wire, 7 ... Opening, 8 ... Lid, 9 ... core wire positioning member, 10 ... pressing member, 11 ... hole (bottom part of metal container 2), 12 ... potential fixing member (high voltage part), 13 ... silicone adhesive, 21 ... hole (of metal container 5) Upper surface portion), 22... Potential fixing member (ground voltage portion side).

Claims (10)

A metal conductor through which a current flows and a photocurrent sensor that measures the current flowing through the metal conductor and converts it into an optical signal are housed, and an optical fiber line for optical signal transmission drawn from the photocurrent sensor is inserted under the container A first metal container provided with a first hole for
A second metal container provided at a grounding site and provided with a second hole through which the optical fiber line is inserted facing the first hole;
A hollow soot tube disposed so as to connect the first metal container above and the second metal container below, and connect between the metal containers;
It is pulled out from the photocurrent sensor, is inserted into the first hole in the first metal container and the second hole in the second metal container, and hangs down linearly at a substantially central part in the soot tube. And an optical fiber line arranged in such a manner.   2. The insulator-type optical current transformer according to claim 1, wherein a plurality of the first holes and the second holes are arranged in the vicinity of the axis of the insulator tube so as to pass through a plurality of optical fiber lines.   The insulator-type optical current transformer according to claim 1, further comprising a potential fixing member that is supported in the second metal container and fixes the optical fiber line with a surplus portion. The extra length portion,
A = √ (L ² + δ ² ) −L (Equation 1)
δ = F · L ³ / (3 · E · I)
Where L is the length of the tubule
F: Concentrated weight acting on the head of the tubule
E: Young's modulus of tubule
I: Secondary moment of inertia
δ: Displacement of the head of the soot tube
A: The amount of sag The insulator type optical current transformer according to claim 3, wherein the amount of sag is equal to or greater than the amount of sag A calculated in (Equation 1).   The insulator type optical current transformer according to any one of claims 1 to 4, wherein a surface roughness of inner peripheral surfaces of the first hole and the second hole is made finer than 25S.   6. The method according to claim 1, wherein at least one of the first hole of the first metal container and the second hole of the second metal container is made of an insulating material. An insulator type optical current transformer according to claim 1.   The insulator type optical current transformer according to claim 6, wherein a fluororesin is used as a main material of the insulating material.   The electric potential fixing member which is arrange | positioned so that it might become an electric potential equivalent to the said 1st metal container in the vicinity of the said 1st hole, and fixed the said optical fiber line | wire is provided. Isogo type optical current transformer.   The insulator type optical current transformer according to claim 3, wherein the potential fixing member is disposed in the vicinity of the second hole so as to have a potential equivalent to that of the second metal container, and the optical fiber line is fixed. vessel.   The insulator type optical current transformer according to claim 8 or 9, wherein a silicone-based adhesive is used for fixing the optical fiber line.

Images