JP5461347B2 - Optical current transformer for electrical equipment - Google Patents

Description

  The present invention relates to an optical current transformer for electrical equipment, and more particularly to an optical current transformer for electrical equipment that can improve current measurement accuracy.

  Usually, electrical equipment such as gas-insulated switchgear, gas circuit breakers, and gas-insulated buses is used as power transmission and distribution equipment. In these electric devices, it has been proposed to use an optical current transformer in order to measure a current flowing through a current-carrying conductor arranged in a container to be sealed.

  Usually, the optical current transformer uses a known optical fiber made of lead glass as a current sensor. In the case of a reflective optical current transformer, a current-carrying conductor 1 through which a current flows is placed inside a container (not shown) of an electric device formed in a cylindrical shape as shown in FIGS. 9 (a) and 9 (b). At the time of arrangement, the optical fiber 2 is wound around the current-carrying conductor 1 so that the current-carrying conductor 1 and the optical fiber 2 are orthogonal (crossed).

  An optical member 3 having a permanent magnet is disposed at one end of the optical fiber 2, and a reflecting member 4 is disposed at the other end. The optical member 3 and the reflecting member 4 are wound around the optical fiber 2. It arrange | positions on the circle | round | yen, ie, the winding extension line | wire of the optical fiber 2 wound so that it may orthogonally cross (cross) with respect to the axis line of the electricity supply conductor 1. FIG. Accordingly, for example, as shown in FIGS. 9A and 9B, when the current I flows from the lower side to the upper side of the conducting conductor 1, the magnetic field H generated in the direction perpendicular to the current I is applied to the optical fiber 2. It has a configuration.

  In this reflection-type optical current transformer, linearly polarized light is incident on the inside of the optical fiber 2 via the optical member 3 on one end side of the optical fiber 2 and is reflected on the other end side of the optical fiber 2. 4 is reflected and returned to a measuring unit (not shown) provided outside. Since the incident linearly polarized light becomes outgoing light rotated by the Faraday effect of the optical fiber, the rotation angle of the outgoing light is detected by the measuring unit, and the energization current is measured.

  In the case of using an optical current transformer incorporated in an electrical device, it has been proposed to use an annular frame having a circumferential groove on an end face in the axial direction in order to arrange an optical fiber wound around a conducting conductor (Patent Document 1). reference). In this optical current transformer, an optical fiber is housed and fixed in a circular groove of an annular frame and intersects with a conducting conductor, and a polarizer portion extending in a circular direction and a detector are formed at both ends of the optical fiber in the circular groove. A photon is placed. By adopting this optical current transformer structure, the total length can be shortened and the optical transmission loss can be reduced as compared with a structure in which an optical fiber is wound around the outer peripheral surface of the annular frame.

  In addition, the optical fiber wound around the current-carrying conductor is rotated by a positive integer number of turns, eliminating the influence of the magnetic field due to the current flowing through the current-carrying conductor even if the circumference of the optical fiber is small. A flow device has been proposed (see Patent Document 2). In this optical current transformer, when the winding end of the optical fiber is bent outward and the input end where the polarizer is placed and the output end where the analyzer is placed are pulled out, from the swung position to the input end and the output end By covering with a magnetic shield, the influence of the magnetic field can be prevented and high accuracy without measurement errors can be achieved.

JP 2000-314751 A JP 2000-121676 A

  In the conventional optical current transformer shown in FIG. 9 and the optical current transformer described in Patent Document 1, the optical member or the like is on a winding circle of an optical fiber that intersects (orthogonal) the axial direction of the conducting conductor 1. In other words, the optical member 3 and the reflecting member 4 are disposed on the winding extension line of the optical fiber that intersects the axial direction of the conducting conductor 1, and the direction of the magnetic field H generated by the current I is the same.

  In such an optical current transformer, the magnetic field created by the current flowing through the current-carrying conductor has a large effect on the permanent magnet in the optical member, causing measurement errors. In other words, this is for the following reason. The permanent magnet in the optical member is used as an optical signal by saturating the angle of the linearly polarized wave by the effect of the magnetic field. When a current flows through the current-carrying conductor, a magnetic field is generated. It is not affected because it is saturated.

  However, when the magnetic field direction of the permanent magnet is opposite to the direction of the magnetic field H due to the current i flowing through the conducting conductor 1, (magnetic field by the permanent magnet) − (magnetic field generated by the current flowing through the conducting conductor) <(vertically polarized light saturation magnetic field). ), It becomes impossible to saturate the linearly polarized wave, which causes an error in the measuring instrument that calculates the current value on the assumption that the magnetic field of the permanent magnet in the optical member 3 is saturated.

  Moreover, like an optical current transformer like patent document 2, the input end which arrange | positions the polarizer of the winding end part of an optical fiber, and the output end which arrange | positions an analyzer are covered with a magnetic shield so that the influence by a magnetic field may be eliminated. In this case, the structure of the winding end portion of the optical fiber becomes complicated and it becomes difficult to manufacture.

  An object of the present invention is to provide an optical current transformer for electrical equipment that can reduce the influence of a magnetic field with a simple structure and improve the measurement accuracy of a current flowing through a conducting conductor.

  An optical current transformer for electrical equipment according to the present invention includes a current-carrying conductor disposed in a container of the electrical equipment, an optical fiber wound and disposed perpendicular to the axial direction of the current-carrying conductor, and one end of the optical fiber. When the optical member is provided with at least a reflecting member provided at the other end, at least the optical member is located in an arbitrary virtual plane in which the magnetic field axis of the permanent magnet passes through the central axis of the conducting conductor. It is characterized by the arrangement.

  Preferably, both the optical member and the reflecting member are arranged on the same axis. Preferably, both the optical member and the reflecting member are juxtaposed close to each other.

  The electrical current transformer for electrical equipment according to the present invention includes an energizing conductor disposed in a container of the electrical apparatus, an optical fiber wound and disposed so as to be orthogonal to the axial direction of the energizing conductor, and the optical fiber. When comprising at least an optical member having a permanent magnet provided at one end and a reflecting member provided at the other end, at least two frame units are combined with a flange formed on the outer surface of the container, and a groove and a storage seat The optical frame is disposed in the groove of the annular frame, and the optical member and the reflecting member are placed close to each other in the storage seat of the annular frame, The optical member is arranged such that the magnetic field axis of the permanent magnet is positioned in an arbitrary virtual plane passing through the central axis of the conducting conductor.

  Preferably, the storage seat of the annular frame is formed to be inclined with respect to the axial direction of the conducting conductor.

  When configured as an optical current transformer for electrical equipment of the present invention, when an optical fiber is wound around a current-carrying conductor, the magnetic field axis is applied to the permanent magnet in the optical member placed at the end of the optical fiber. Since it is arranged in a virtual plane formed by the conductor axis, the magnetic field of the permanent magnet is significantly less affected by the magnetic field generated by the current flowing in the conducting conductor. For this reason, the optical current transformer for electric equipment of the present invention can further improve the current measurement accuracy compared with the conventional optical current transformer with a simple configuration.

(A) is a schematic perspective view of the optical current transformer for electrical devices which is one Example of this invention, (b) is a top view of (a). (A) is a schematic perspective view of the optical current transformer for electric devices which is the other Example of this invention, (b) is a schematic plan view of (a). (A) is a schematic longitudinal cross-sectional view of the optical member used for the electrical current transformer for electric equipment of FIG.1 and FIG.2, (b) is the schematic of the reflective member used for the optical current transformer for electrical equipment of FIG.1 and FIG.2. It is a longitudinal cross-sectional view. It is a schematic block diagram of the gas circuit breaker to which the optical current transformer for electrical devices of this invention is applied. (A) is a front view showing a partial cross section of an optical current transformer for electrical equipment to which the present invention is applied, (b) is a plan view of (a) showing a partial cross section, and (c) is a partial cross section. It is a right view of (b) shown. It is a perspective view which shows the optical current transformer for electric devices of FIG. (A) is a front view showing another cross section of another electrical current transformer for electrical equipment to which the present invention is applied, (b) is a plan view showing (a) a partial cross section, and (c) is one It is a right view of (b) shown with a partial cross section. It is a perspective view which shows the optical current transformer for electric devices of FIG. (A) is a schematic perspective view which shows the conventional optical current transformer for electric equipments, (b) is a top view of (a).

  An optical current transformer for electrical equipment according to the present invention has a current-carrying conductor arranged in a container of an electric equipment, and an optical fiber is wound and arranged so as to be orthogonal to the axial direction of the current-carrying conductor. An optical member having a permanent magnet is provided at one end, and a reflecting member is provided at the other end. The optical member is arranged so that the magnetic field axis of the permanent magnet is located in an arbitrary virtual plane passing through the central axis of the conducting conductor.

  Hereinafter, the optical current transformer for electric equipment of the present invention will be described in order with reference to FIGS. As shown in FIGS. 1 (a) and 1 (b), a conducting conductor 1 through which a current flows is disposed inside a container (not shown) of an electric device formed in a cylindrical shape, and is used by sealing an insulating gas. An optical fiber 2 is wound around the current-carrying conductor 1 for at least one turn so as to surround it.

  Both ends of the wound optical fiber 2 are bent in the same direction as the length direction (axial direction) of the current-carrying conductor 1, and one end of the optical fiber 2 on which linearly polarized light enters as in the conventional case. The optical member 3 is provided at the other end, and the reflecting member 4 is provided at the other end. The optical member 3 is connected to a light source disposed outside and a measuring unit for measuring current. In addition, both the optical member 3 and the reflecting member 4 are arranged on the same axis shown by a one-dot chain line in FIG. 1A so as to be in the same direction as the axial direction of the conducting conductor 1.

  The optical member 3 provided at one end of the optical fiber 2 includes a permanent magnet 3A and a birefringent element 3B that generate a magnetic field H1 and is used in a saturated state as shown in FIG. It is used by being disposed on the end face of the optical fiber 2 on the incident side. The reflecting member 4 provided at the other end of the optical fiber 2 is configured to have a mirror surface 4A as shown in FIG. 3B, and is arranged so as to reflect linearly polarized light and return inside the optical fiber 2. used.

  According to the present invention, the optical member 3 and the reflecting member 4 are arranged in an arbitrary virtual plane that passes through the central axis of the conducting conductor 1. Thereby, the magnetic field axis of the permanent magnet 3 </ b> A included in the optical member 3 is positioned in an arbitrary virtual plane passing through the central axis of the conducting conductor 1. In other words, in the optical current transformer for electric equipment of FIG. 1A, the axial direction of the conducting conductor 1 that generates the magnetic field H through the current I flows, and the optical member 3 and the reflecting member 4 are arranged in parallel. Is in a state of intersecting with the winding circle portion of the optical fiber 2.

  Note that an arbitrary virtual plane passing through the central axis of the conductive conductor 1 is a plurality of planes when it is assumed that a plane is formed on the side of the entire outer peripheral surface of the conductive conductor 1 through the central axis of the conductive conductor 1. It means one plane inside.

  As a result, in the optical current transformer for electrical equipment according to the present invention, the magnetic field H generated by the current I flowing through the conducting conductor 1 is added to the linearly polarized light passing through the optical fiber 2 and the Faraday rotation angle is large according to the strength of the magnetic field H. You can change the size. However, since the optical member 3 at the end of the optical fiber 2 has the magnetic field axis of the permanent magnet 3A positioned in an arbitrary virtual plane passing through the central axis of the conducting conductor 1, the optical member 3 can be configured with a simple configuration. In addition, the reflecting member 4 is less affected by the magnetic field H generated by the current I flowing through the current-carrying conductor 1, and the measurement accuracy of the current measured by the measuring unit can be further improved compared to the conventional one.

  2 (a) and 2 (b) which is another embodiment of the present invention, the optical fiber 2 is wound so as to surround the current-carrying conductor 1 in the same manner as the above-described embodiment. The both ends are bent in the same direction as the axial direction of the conducting conductor 1.

  The optical member 3 provided at one end of the optical fiber 2 and the reflecting member 4 provided at the other end are arranged so as to be in close contact with each other, and the optical member 3 and the reflecting member 4 are The magnetic field axis of the permanent magnet 3A included in the optical member 3 is positioned in an arbitrary virtual plane passing through the central axis of the conductive conductor 1. In other words, the axial direction of the current-carrying conductor 1 and the axial direction of the optical member 3 and the reflecting member 4 are arranged in parallel, and the optical member 3 and the reflecting member 4 intersect with the winding circle of the optical fiber 2.

  Even if the optical current transformer for electrical equipment in which the optical member 3 and the reflecting member 4 are arranged as described above, it is not easily influenced by the magnetic field H generated by the current I flowing through the conducting conductor 1, so that it is the same as the above example. Effects can be achieved.

  FIG. 4 shows an example in which the above-described optical current transformers for electric appliances are applied to the gas circuit breaker 10 in which an operation device for opening and closing an internal circuit breaker (not shown) is provided on the side. ing. The conducting conductor through which the current I flows in series with the breaker of the gas circuit breaker 10 is disposed in the cylindrical containers 12A and 12B drawn upward.

  The gas circuit breaker 10 is an electric circuit in which the optical member 2 and the reflecting member 4 shown in FIGS. 1A and 1B are arranged on the same axis by winding the optical fiber 2 around the outer surface of the container 12A. An optical current transformer for equipment is configured, and the optical fiber 2 is wound around the outer surface of the containers 12A and 12B, and the optical member 3 and the reflecting member 4 shown in FIGS. The optical current transformer for electric equipment arranged is configured.

  A specific structure to which the above-described optical current transformer for electrical equipment shown in FIGS. 2 (a) and (b) is applied is shown in FIGS. 5 (a), (b), (c) and FIG. The container 20 of the electrical equipment in which the current-carrying conductor 1 is disposed has flanges 20A on the outer surface, and the mounting frame 24 is fixed to a plurality of locations of the flange 20A with fixing means such as bolts 25, and the annular frame 21 is formed. Removably attached.

  In order to facilitate the manufacture and attachment of the annular frame 21, for example, frame units 21A and 21B formed into at least two divided arcs are combined and integrated by a coupling means such as a connecting bolt 21C. . In the annular frame 21, a groove 22 that goes around the container 20 and a flat storage seat 23 that is substantially parallel to the axial direction of the conducting conductor are formed in a part of the groove 22.

  An optical fiber 2 wound around the current-carrying conductor 1 is disposed in a groove 22 provided in the annular frame 21 so that the optical fiber 2 is pulled out to the outside where the measuring unit is provided, and an optical provided at each end of the optical fiber 2 in the storage seat 23. The member 3 and the reflecting member 4 are arranged close to each other, and the protective cover 26 is attached. When the protective cover 26 is made of, for example, a non-magnetic material capable of shielding the magnetic field H, the optical member 3 and the reflecting member 4 are more effective in preventing the influence of the magnetic field H generated by the current I flowing through the conducting conductor 1. is there. A closing plate can be attached to the groove 22 of the annular frame 21 so that the optical fiber 2, the optical member 3, and the reflecting member 4 are covered with the closing plate.

  Thus, if the optical fiber 2, the optical member 3, and the reflecting member 4 are arranged by utilizing the groove 22 and the storage seat 23 provided in the annular frame 21, it can be easily arranged at a desired position. The magnetic field axis of the permanent magnet 3 </ b> A in the optical member 3 is positioned in an arbitrary virtual plane that passes through the central axis of the conducting conductor 1.

  The housing seat 23 provided in a part of the groove 22 of the annular frame 21 is provided to be inclined with respect to the axis of the conducting conductor 1 as shown in FIGS. 7 (a), (b), (c) and FIG. You can also. The optical member 3 and the reflecting member 4 are juxtaposed with the inclined storage seat 23 portion, and the other portions are the same as in the examples of FIGS. 5 (a), (b), (c) and FIG. Structure. Thereby, the optical member 3 and the reflecting member 4 are arranged so as to be inclined at a constant angle with respect to the axis of the current-carrying conductor 1, and the magnetic field axis of the permanent magnet in the optical member is arbitrarily passed through the central axis of the current-carrying conductor 1. Since the optical current transformer for electrical equipment is configured in the virtual plane, the same effect can be achieved.

  The inclination angle of the storage seat 23 of the annular frame 21 can be determined as appropriate. However, when the inclination angle of the storage seat 23 is increased, the radial dimension of the groove 22 is increased due to the arrangement of the optical member 3 and the reflection member 4. There is a disadvantage that the entire annular frame 21 becomes large. For this reason, the storage seat 23 is formed at an inclination angle of, for example, about ± 5 degrees with respect to the axis of the conducting conductor 1, the optical member 3 and the reflecting member 4 can be easily arranged, and parallel to the axial direction of the conducting conductor 1. Use in an arrangement with larger ingredients.

  In each of the above-described optical current transformers for electric appliances, the optical member 3 and the reflecting member 4 are both disposed at the same position. However, only the optical member 3 of the current-carrying conductor 1 is used. The magnetic field axis of the permanent magnet 3 </ b> A that is disposed in an arbitrary plane passing through the central axis and is in the optical member 3 can be used.

DESCRIPTION OF SYMBOLS 1 ... Current-carrying conductor, 2 ... Optical fiber, 3 ... Optical member, 4 ... Reflective member, 20 ... Container, 20A ... Flange, 21 ... Annular frame, 21A, 21B ... Frame body unit, 22 ... Groove, 23 ... Storage seat .

Claims (5)

  An energizing conductor disposed in a container of an electrical device, an optical fiber wound and disposed so as to be orthogonal to the axial direction of the energizing conductor, an optical member having a permanent magnet provided at one end of the optical fiber, and the other end In the optical current transformer for electrical equipment provided with the reflecting member to be provided, at least the optical member is disposed so that the magnetic field axis of the permanent magnet is located in an arbitrary virtual plane passing through the central axis of the conducting conductor. Features an optical current transformer for electrical equipment.   2. The optical current transformer for electrical equipment according to claim 1, wherein both the optical member and the reflecting member are arranged on the same axis.   2. The optical current transformer for electrical equipment according to claim 1, wherein both the optical member and the reflecting member are juxtaposed in close proximity to each other.   An energizing conductor disposed in a container of an electrical device, an optical fiber wound and disposed so as to be orthogonal to the axial direction of the energizing conductor, an optical member having a permanent magnet provided at one end of the optical fiber, and the other end An electrical current transformer for an electrical apparatus comprising at least a reflecting member to be provided, wherein at least two frame units are combined with a flange formed on the outer surface of the container, and an annular frame having a groove and a storage seat is detachably fixed. The optical fiber is disposed in the groove of the annular frame body, and the optical member and the reflecting member are arranged close to each other on the storage seat of the annular frame body, and the optical member is a magnetic field axis of the permanent magnet. Is arranged so as to be located in an arbitrary virtual plane passing through the central axis of the current-carrying conductor.   5. The optical current transformer for an electric device according to claim 4, wherein the storage seat of the annular frame is formed to be inclined with respect to the axial direction of the conducting conductor.

Images