Support and current measuring sensor

Abstract

To stably support a coil for current measurement around an insulating cylinder of a terminal connection portion.SOLUTION: A support 100 includes a flexible ring 101 that is formed in a ring shape along the circumferential direction, and includes a notch 101a extending from the outer circumference to the inner circumference, and a slit 101b extending in the circumferential direction between the outer circumference and the inner circumference, and a plurality of hooks 102 arranged in the circumferential direction on the outer peripheral side of the ring 101 relative to the slit 101b.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a support and a current measuring sensor. [Background technology]

[0002] A power cable is connected to an electric device such as a gas-insulated switchgear installed in a power system via a termination connection part (see, for example, Patent Document 1). A power cable is formed by covering the outer circumference of a conductor core with an inner semiconductor layer, an insulator layer, an outer semiconductor layer, a shield layer, and a sheath in that order. The termination connection part includes a cylindrical bushing, an adapter, an insulating tube, and a protective metal tube that are connected in the axial direction and into which the end of the power cable is inserted, a conductor pull-out rod that is connected to the conductor core exposed at the end of the power cable, and a stress relief cone that is fitted on the exterior of the power cable within the bushing.

[0003] A surge occurs in an electric device when the device is turned off or charged. A surge also occurs due to lightning or a ground fault. A surge can cause insulation breakdown and affect the lifespan of equipment. In order to detect the occurrence of a surge, the current flowing through the conductor core of a power cable is observed (see, for example, Patent Document 2). A Rogowski coil is used to measure the current. However, simply winding a Rogowski coil around a power cable cannot accurately measure the current flowing through the conductor core of the power cable, particularly the excessive current caused by a surge. This is because the surge component of the current flowing through the conductor core escapes into the shield layer, making it difficult for the Rogowski coil to capture the magnetic field caused by the surge component of the current flowing through the conductor core. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-231654 A [Patent Document 2] JP 2007-020301 A Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, inside the termination part, the end of the power cable is stripped and the shield layer is also stripped. If a Rogowski coil is wound around the insulating tube of the termination part, the current flowing through the conductor core of the power cable can be measured using the Rogowski coil. However, there is a problem with fixing the Rogowski coil. That is, since there is no protrusion or the like on the outer surface of the insulating tube of the termination part, the Rogowski coil wound around the insulating tube cannot be stably supported.

[0006] The present invention has been made in consideration of the above circumstances, and has an object to make it possible to stably support a current measuring coil around an insulating tube of a terminal connection portion. [Means for solving the problem]

[0007] In order to solve the above problems, the support device comprises a flexible ring formed in a ring shape along the circumferential direction, having a notch extending from the outer periphery to the inner periphery and having a slit extending in the circumferential direction between the outer periphery and the inner periphery, and a plurality of hooks arranged in the circumferential direction on the outer periphery side of the ring relative to the slit.

[0008] Preferably, the ring surrounds a cylindrical adapter that constitutes a terminal connection part for connecting a power cable to an electrical equipment, and is placed on a flange provided at the lower end of the outer periphery of the adapter, a plurality of bolt heads arranged in the circumferential direction on the flange are inserted into the slits, the hook hangs down from the outer periphery of the flange and is positioned around an insulating tube connected below the adapter, and a Rogowski coil wound around the insulating tube is hung on the hook.

[0009] In order to solve the above problems, a current measurement sensor is provided which extends vertically inside a cylindrical adapter constituting a terminal connection part for connecting a power cable to an electrical device and an insulating tube connected below the adapter, and which measures the current of the power cable from which a shielding layer has been stripped inside the adapter and the insulating tube, the current measurement sensor comprising a Rogowski coil and a support, the support being formed in a ring shape along the circumferential direction and having a notch extending from the outer periphery to the inner periphery, a flexible ring having a slit extending in the circumferential direction between the outer periphery and the inner periphery, and a plurality of hooks arranged in the circumferential direction on the outer periphery side of the ring relative to the slit, the ring surrounding the adapter and placed on a flange provided at the lower end of the outer periphery of the adapter, a plurality of bolt heads arranged in the circumferential direction on the flange are inserted into the slits, the hooks hang down from the outer periphery of the flange and are located around the insulating tube, and the Rogowski coil wound around the insulating tube is hung on the hooks.

[0010] According to the above, the notch extends from the outer circumference to the inner circumference of the ring, so that the adapter can be surrounded by the ring. When the ring is placed on the flange, the bolt head is inserted into the slit, so that the ring can be well placed on the flange. Such a ring is provided with multiple hooks in the circumferential direction, and the coil wound around the insulating tube is hung on these hooks, so that the coil can be stably supported around the insulating tube. Effect of the Invention

[0011] According to the present invention, the coil can be stably supported around the insulating cylinder. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a perspective view of a support and a Rogowski coil. [Diagram 2] FIG. 2 is a perspective view showing a manner in which the support and the Rogowski coil are used. [Diagram 3] FIG. 4 is a partial cross-sectional view of a terminal connection portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, the embodiments of the present invention will be described with reference to the drawings. The embodiments described below are subject to various technically preferable limitations for carrying out the present invention, and the scope of the present invention is not limited to the following embodiments and illustrated examples.

[0014] [Overview of how the support and Rogowski coil are used] FIG. 1 is a perspective view of the support 100 and the Rogowski coil 120. FIG. 2 is a perspective view showing a usage mode of the support 100 and the Rogowski coil 120. As shown in FIG. 2, the support 100 is attached to the terminal connection part 1 of the power cable 10, and the Rogowski coil 120 is supported around the terminal connection part 1 of the power cable 10 using the support 100. Then, the current of the power cable 10 in the terminal connection part 1 is measured using the Rogowski coil 120. First, the terminal connection part 1 and the power cable 10 will be described with reference to FIG. 3. In the following description, the direction from top to bottom is the direction in which gravity acts.

[0015] [Termination and power cables] FIG. 3 is a partial cross-sectional view of the termination 1 of the power cable 10. As shown in FIG. The termination connection portion 1 connects an end 11 of a power cable 10 to electric power equipment such as a gas insulated switchgear (GIS). The end 11 of the power cable 10 refers to a portion that has been subjected to a step stripping process as described below. The electric power equipment has an upper case and a lower inspection chamber 3. The internal space of the case is separated from the inspection chamber 3 by the case bottom plate 2. The internal space of the case is filled with sulfur hexafluoride gas, which has excellent electrical insulating properties. The terminal connection part 1 is passed through a communication hole 2a formed in the bottom plate 2, and the terminal connection part 1 is installed on the electric power equipment so that the upper part of the terminal connection part 1 is located inside the case and the lower part of the terminal connection part 1 is located inside the inspection room 3. The bottom plate 2 is grounded.

[0016] The power cable 10 is a CV cable. The power cable 10 has a conductor core 12, an inner semiconductor layer (not shown), an insulator layer 13, an outer semiconductor layer 14, a shield layer 15, and a sheath 16, which are coated on the outer circumference of the conductor core 12 in this order. Here, as described above, the end 11 of the power cable 10 is stripped in stages. Specifically, the sheath 16, the shield layer 15, the outer semiconductor layer 14, the insulator layer 13, and the inner semiconductor layer are stripped away so that the sheath 16, the shield layer 15, the outer semiconductor layer 14, the insulator layer 13, and the conductor core 12 are exposed in this order toward the end of the power cable 10. The power cable 10 shown in FIG. 3 has one conductor core 12, but instead of this, a multi-core power cable having multiple conductor cores may be adopted.

[0017] The terminal connection portion 1 has a conductor pull-out rod 20, a bushing 30, a stress relief cone 40, a pressing device 50, an adapter 60, an insulating tube 70, and a protective metal tube 80.

[0018] The bushing 30, the adapter 60, the insulating tube 70, and the protective metal tube 80 are cylindrical bodies around an axis with the up-down direction being the axial direction. The upper and lower ends of the bushing 30, the adapter 60, the insulating tube 70, and the protective metal tube 80 are open. The bushing 30 and the insulating tube 70 are electrically insulating, and the adapter 60 and the protective metal tube 80 are conductive. The bushing 30, the adapter 60, the insulating tube 70, and the protective metal tube 80 are connected in this order from above in the axial direction. The direction around the axis of the bushing 30, the adapter 60, the insulating tube 70, and the protective metal tube 80 is called the circumferential direction.

[0019] A flange 31 is provided at the lower end of the outer periphery of the bushing 30. A flange 61 is also provided at the upper end of the outer periphery of the adapter 60. These flanges 31, 61 are fixed to each other with bolts or the like. This connects the lower end of the bushing 30 to the upper end of the adapter 60. The flange 61 of the adapter 60 is fixed onto the bottom plate 2 around the communicating hole 2a of the bottom plate 2, and the adapter 60 protrudes below the bottom plate 2 through the communicating hole 2a. The adapter 60 is grounded via the bottom plate 2.

[0020] A flange 62 is provided at the lower end of the outer periphery of the adapter 60. The flange 62 has through holes arranged in the circumferential direction. The bolts 63 pass through the through holes of the flange 62 and are screwed into the insulating tube 70. In other words, the flange 62 is fastened to the upper end of the insulating tube 70 by the bolts 63. The heads of the bolts 63 are arranged at intervals on the flange 62 in the circumferential direction.

[0021] The lower end of the insulating cylinder 70 is fastened to a flange 81 provided at the upper end of a protective metal tube 80 by bolts (not shown) arranged in the circumferential direction. The protective metal tube 80 is grounded.

[0022] The end 11 of the power cable 10 is inserted into the protective metal tube 80, the insulating tube 70, the adapter 60, and the bushing 30 from the lower side of the protective metal tube 80. A protective tape 82 is wound around the protective metal tube 80 and the power cable 10 near the opening at the lower end of the protective metal tube 80. The opening at the lower end of the protective metal tube 80 is sealed by the protective tape 82. The shield layer 15 of the power cable 10 is stripped inside the insulating tube 70 and above it, and the part inside the shield layer 15 is exposed. Therefore, the current of the power cable 10 can be measured using a Rogowski coil 120 wound around the insulating tube 70 as shown in FIG. 2. The shield layer 15 is grounded via the protective metal tube 80.

[0023] 1, the conductor pull-out rod 20 protrudes upward from inside the bushing 30 through an opening at the upper end of the bushing 30 and is fixed to the upper end of the bushing 30 by a fastener 21. Inside the bushing 30, the conductor pull-out rod 20 is connected to the exposed conductor core 12 of the power cable 10.

[0024] The stress relief cone 40 is fitted into the bushing 30 and is sheathed on the exposed insulation layer 13 of the power cable 10. The stress relief cone 40 is pressed upward by a pressing device 50 provided inside the bushing 30, the adapter 60, the insulating tube 70, and the protective metal tube 80, and is pressed against the cone surface on the inner circumference of the bushing 30.

[0025] [Support] The support 100 will be described with reference to FIGS. The support 100 includes a ring 101 and a number of hooks 102 .

[0026] The ring 101 is a flexible ring-shaped member extending in the circumferential direction, and more specifically, is a sheet material or thin plate material having a small thickness in the axial direction. The ring 101 is made of, for example, a rubber elastic body. The ring 101 has a notch 101a extending from the outer periphery of the ring 101 to the inner periphery of the ring 101, so that the ring 101 is C-shaped. Since the ring 101 is flexible, the notch 101a can be expanded in the circumferential direction and the axial direction. Therefore, the adapter 60 of the termination connection part 1 shown in FIG. 3 can be passed through the notch 101a, and the ring 101 can be installed so as to surround the adapter 60 as shown in FIG. 1.

[0027] Between the outer and inner circumferences of the ring 101, C-shaped slits 101b are formed so as to extend in the circumferential direction and penetrate the ring 101 in the thickness direction. When the ring 101 is placed on the flange 62 as shown in Fig. 2, the heads of the bolts 63 are inserted into the slits 101b. This allows the ring 101 to be well-placed on the flange 62. In addition, the heads of any of the bolts 63 come into contact with the circumferential ends of the slits 101b, preventing the ring 101 from unexpectedly moving significantly in the circumferential direction.

[0028] A plurality of hooks 102 are provided on the ring 101 on the outer periphery side of the ring 101 relative to the slits 101b. Specifically, these hooks 102 are provided on the outer periphery of the ring 101 at intervals in the circumferential direction. These hooks 102 and the ring 101 are integrally formed. The hooks 102 extend in the axial direction from the outer periphery of the ring 101, and the tip portions of the hooks 102 are bent radially outward of the ring 101 and folded back toward the ring 101.

[0029] 2, when ring 101 surrounds adapter 60 on flange 62, hook 102 hangs down from the outer periphery of flange 62, and the folded back portion of hook 102 is positioned around insulating tube 70. Note that hook 102 may contact the outer periphery of insulating tube 70.

[0030] [Rogowski coil] The Rogowski coil 120 has an air-core winding (not shown) and a return wire (not shown) housed in a sheath 121. Both ends of the Rogowski coil 120 are connected by a connector 122, and the Rogowski coil 120 is formed into a ring shape. One end of the Rogowski coil 120 can be removed from the connector 122.

[0031] The Rogowski coil 120 is wound around the insulating tube 70 and hung on the hook 102. The Rogowski coil 120 generates an induced electromotive force at a level corresponding to the level of the current in the power cable 10. The Rogowski coil 120 is connected to an integrator via an output cable 123, and a voltage signal representing the level of the induced electromotive force in the Rogowski coil 120 is integrated by the integrator. The level of the output signal of the integrator is proportional to the level of the current in the power cable 10. The output signal of the integrator is input to a display device or a recording device, or both. The display device displays the value of the measured current based on the output signal of the integrator. The recording device records the value of the measured current based on the output signal of the integrator.

[0032] Here, the combination of the Rogowski coil 120 and the support 100, that is, the ring-shaped Rogowski coil 120 hung on the hook 102 of the support 100, is called a current measuring sensor.

[0033] [Current measurement method using a support and Rogowski coil] Ring 101 is deformed to widen notch 101a of ring 101. Adapter 60 is passed through notch 101a, and adapter 60 is surrounded by ring 101. Then, while positioning hook 102 outside the outer periphery of flange 62, ring 101 is placed on flange 62 and hook 102 is hung down from flange 62. Then, insulating tube 70 is surrounded by hooks 102. When ring 101 is placed on flange 62, the head of bolt 63 is inserted into slit 101b.

[0034] One end of the Rogowski coil 120 is removed from the connector 122. The Rogowski coil 120 is wound once around the insulating tube 70, and one end of the Rogowski coil 120 is connected to the connector 122. The loop-shaped Rogowski coil 120 is hung on the hook 102. The shape of the Rogowski coil 120 is also adjusted so that the shape of the Rogowski coil 120 is circular.

[0035] After the Rogowski coil 120 is supported around the insulating tube 70 by the support 100 as described above, the current of the power cable 10 is measured using the Rogowski coil 120. After the current measurement is completed, one end of the Rogowski coil 120 is removed from the connector 122, and the Rogowski coil 120 is removed from the hook 102. Next, the ring 101 is lifted from the flange 62, and the adapter 60 is passed through the notch 101a of the ring 101, and the ring 101 is removed from around the adapter 60.

[0036] [Advantageous Effects] (1) The support 100 is attached to the termination 1 by utilizing the outer shape of the termination 1. That is, the ring 101 is wrapped around the cylindrical adapter 60 and placed on the flange 62, and the heads of the bolts 63 are inserted into the slits 101b of the ring 101. Therefore, the support 100 can be used to support the Rogowski coil 120 around the insulating cylinder 70 without processing the outer surface of the termination 1.

[0037] (2) A number of hooks 102 hang down from the flange 62, with the folded-back portions at the tips of the hooks 102 positioned around the insulating tube 70, and the Rogowski coil 120 wound around the insulating tube 70 is hooked onto these hooks 102. Therefore, the Rogowski coil 120 can be stably supported around the insulating tube 70 without having to attach the Rogowski coil 120 to the outer circumferential surface of the insulating tube 70 with adhesive tape or the like.

[0038] (3) Since the ring 101 surrounds the adapter 60, the ring 101, the adapter 60, and the power cable 10 can be arranged concentrically. A plurality of hooks 102 are provided in the circumferential direction on such ring 101, and the Rogowski coil 120 is hung on these hooks 102. Therefore, the row of hooks 102, the Rogowski coil 120, and the power cable 10 can be arranged concentrically. In this way, the distance from the Rogowski coil 120 to the center of the power cable 10 can be made uniform, and therefore the current in the conductor core 12 can be measured stably and accurately.

[0039] (4) A slit 101b is formed in the ring 101, and the head of the bolt 63 is inserted into the slit 101b. This allows the ring 101 to be stably placed on the flange 62, and prevents the ring 101 from losing its shape or shifting in position due to the weight of the Rogowski coil 120. This allows the Rogowski coil 120 to be stably supported around the insulating cylinder 70.

[0040] (5) The slits 101b extend in the circumferential direction and are C-shaped. Therefore, regardless of the number of bolts 63, the heads of the bolts 63 can be inserted into the slits 101b.

[0041] (6) The ring 101 has a notch 101a and is C-shaped. This allows the ring 101 to be attached to and detached from the periphery of the adapter 60 without disassembling the terminal connection part 1. This allows the support 100 to be used for other terminal connections.

[0042] (7) Since the ring 101 is flexible, the ring 101 can be folded. Therefore, the support device 100 can be stored in a compact size.

[0043] (8) Since the ring 101 and the hook 102 are integrally formed, the support 100 is easy to handle. [Explanation of symbols]

[0044] 1...Terminal connection part 60…Adapter 61...Flange 63…Bolt 70…Insulating tube 100...Support 101...Ring 101a...notch 101b...Slit 102…Hook 120…Rogowski coil

Claims

1. a flexible ring formed in a ring shape along a circumferential direction, having a notch extending from an outer periphery to an inner periphery, and having a slit extending in the circumferential direction between the outer periphery and the inner periphery; A support comprising: a plurality of hooks arranged in the circumferential direction on the outer circumferential side of the ring relative to the slits.

2. The ring surrounds a cylindrical adapter that constitutes a terminal connection portion for connecting a power cable to an electric device, and is placed on a flange provided at a lower end of an outer periphery of the adapter, A plurality of bolt heads arranged in the circumferential direction are inserted into the slits, the hook depends from the outer periphery of the flange and is positioned around an insulating tube connected below the adapter; A Rogowski coil wound around the insulating tube is hung on the hook. The support of claim 1 .

3. A current measurement sensor that extends vertically inside a cylindrical adapter constituting a terminal connection part for connecting a power cable to an electric device and an insulating tube connected thereto, and measures a current of the power cable from which a shield layer has been stripped inside the adapter and the insulating tube, A Rogowski coil and a support are provided. The support includes: a flexible ring formed in a ring shape along a circumferential direction, having a notch extending from an outer periphery to an inner periphery, and having a slit extending in the circumferential direction between the outer periphery and the inner periphery; a plurality of hooks arranged in the circumferential direction on an outer circumferential side of the ring relative to the slits; The ring surrounds the adapter and is mounted on a flange provided at a lower end of the outer periphery of the adapter; A plurality of bolt heads arranged in the circumferential direction on the flange are inserted into the slits, the hook hangs down from an outer periphery of the flange and is positioned around the insulating tube, The Rogowski coil wound around the insulating tube is hung on the hook. Current measurement sensor.

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