Gas-insulated switchgear

Abstract

To suppress the increase in electric field intensity near a triple point while mitigating the maximum electric field intensity around an insulating spacer.SOLUTION: A gas-insulated switchgear (10) comprises: a sealed container (12); an insulating spacer (13) fixed in the sealed container; and high-voltage conductors (14) positioned on both sides of the center of the insulating spacer. The insulating spacer includes: a central conductor (21) connected to the high-voltage conductors; and a spacer body (22) provided in the periphery of the central conductor. The high-voltage conductor includes: a conductor body (24) which extends in the longitudinal direction; and a bulging section (25) which is formed near the outer peripheral surface of the spacer body in the conductor body. The conductor body and the bulging section are provided on the same central axis with their cross-sections perpendicular to the central axis each formed in a circular shape. The bulging section protrudes by a bulging distance (d) in the radial direction of the conductor body, and the ratio of the bulging distance to a radius (r) of the conductor body is set to 5.1% or more and 20% or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a gas-insulated switchgear, and more particularly to a gas-insulated switchgear using an insulating spacer. [Background technology]

[0002] Patent Document 1 discloses a gas-insulated switchgear in which an insulating spacer is used to connect a grounded metal container and a high-voltage conductor, and a shield electrode with a larger diameter than the high-voltage conductor is used. The shield electrode is provided in a relatively high electric field portion including the maximum electric field, and is set to a relatively large diameter to alleviate the electric field strength, while the high-voltage conductor is provided in a relatively low electric field portion and is set to a relatively small diameter. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-320156 A Summary of the Invention [Problem to be solved by the invention]

[0004] The shield electrode formed as in Patent Document 1 is provided with a relatively large diameter, placing importance on mitigating electric field concentration at the triple junction between the insulating spacer, the high-voltage side conductor, and the insulating gas sealed in the container. On the other hand, a shield electrode with a large diameter has a small distance from the insulating part of the insulating spacer, and the electric field strength at the maximum electric field point in the shield electrode increases. Therefore, the present inventors conducted various analyses and studies and discovered a configuration that can satisfactorily mitigate both the maximum electric field strength of the shield electrode and the electric field strength at the triple junction.

[0005] The present invention has been made in consideration of the above-described circumstances, and aims to provide a gas-insulated switchgear that can suppress an increase in electric field strength near the triple junction while mitigating the maximum electric field strength around the insulating spacer. [Means for solving the problem]

[0006] A gas-insulated switchgear according to one embodiment of the present invention is a gas-insulated switchgear comprising a sealed container, an insulating spacer fixed inside the sealed container, and a high-voltage conductor arranged on both sides of the center of the insulating spacer, wherein the insulating spacer comprises a central conductor connected to the high-voltage conductor and a spacer body arranged around the central conductor, the high-voltage conductor comprises a conductor body extending in the longitudinal direction and a bulge portion formed in the conductor body near the outer circumferential surface of the spacer body, the conductor body and the bulge portion are arranged on the same central axis and each has a circular cross section perpendicular to the central axis, the bulge portion protrudes in the radial direction of the conductor body by a bulge distance, and a ratio of the bulge distance to the radius of the conductor body is set to be 5.1% or more and 20% or less. Effect of the Invention

[0007] According to the present invention, in a high-voltage conductor, the ratio of the bulge distance of the bulge to the radius of the conductor body is set to 20% or less, so that the diameter of the bulge can be made smaller than in the past, and the electric field strength at the maximum electric field point at the bulge can be reduced. Moreover, the ratio of the bulge distance of the bulge to the radius of the conductor body is set to 5.1% or more, so that the increase in the electric field strength near the triple junction can be suppressed. This makes it possible to effectively reduce both the maximum electric field strength at the bulge and the electric field strength at the triple junction. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view of a gas-insulated switchgear according to an embodiment. [Diagram 2] 13 is a graph showing the analysis results of the maximum electric field strength at the triple junction versus the bulge distance ratio. [Diagram 3] 13 is a graph showing an analysis result of the electric field strength at the maximum electric field point versus the proportion of the bulge distance. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A gas-insulated switchgear (hereinafter simply referred to as "switchgear") using an insulating spacer according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings. Note that the present invention is not limited to the following embodiment, and can be appropriately modified within the scope of the present invention. In the following drawings, some components may be omitted for the sake of convenience.

[0010] Fig. 1 is a cross-sectional view of a gas-insulated switchgear according to an embodiment. As shown in Fig. 1, a switchgear 10 includes a sealed container 12, an insulating spacer 13 fixed inside the sealed container 12, and a high-voltage conductor 14 arranged on both sides of the center of the insulating spacer 13. The sealed container 12 is filled with dry air or SF6 gas as insulating gas G.

[0011] A metal flange 16 is attached to the outer periphery of the insulating spacer 13 , and the insulating spacer 13 is fixed to the sealed container 12 by sandwiching the metal flange 16 between a connecting flange 17 of the sealed container 12 .

[0012] The insulating spacer 13 includes a central conductor 21 formed in an axial shape, and a spacer body 22 that supports the central conductor 21 and is provided around the central conductor 21 .

[0013] The high voltage conductors 14 are connected to both sides of the central conductor 21 in the extension direction. The spacer body 22 is formed in a cone shape with the axis A direction being the same as that of the central conductor 21. One surface of the spacer body 22 along the axis A direction is formed as a convex surface C, and the other surface is formed as a concave surface R. The central conductor 21 is supported in a top side region of the spacer body 22, and the portion of the central conductor 21 embedded in the top side region of the spacer body 22 is provided in a bulging shape with a larger diameter.

[0014] The spacer body 22 is formed from a resin material that exhibits insulating properties. Although the material of the spacer body 22 is not limited, it is configured by mixing inorganic filler into thermosetting resin. As the thermosetting resin, epoxy resin can be preferably used. As the inorganic filler, it is preferable to add at least one of alumina, silica, dolomite, titanium oxide, barium titanate, and strontium titanate.

[0015] The shapes of the illustrated central conductor 21 and spacer body 22 are merely schematic examples for ease of understanding, and the dimensions in the axial A direction and radial direction, thickness, etc. may be changed as appropriate. Although the insulating spacer 13 is illustrated as a single-phase type, the configuration of this embodiment can be applied to a three-phase lump-sum insulating spacer. In a three-phase lump-sum insulating spacer, the number of central conductors 21 is changed to three, and the penetrating portions of each of the three central conductors 21 in the spacer body 22 are formed into a cone shape.

[0016] The high voltage conductor 14 includes a conductor body 24 extending in the longitudinal direction (the left-right direction in FIG. 1) and a bulge 25 formed on the conductor body 24 in the vicinity of the outer circumferential surface of the spacer body 22.

[0017] The conductor body 24 and the bulge portion 25 are arranged on the same central axis, with the axis A as the central axis, and are also arranged on the same central axis (axis A) with respect to the central conductor 21. The conductor body 24 and the bulge portion 25 are each formed so that the cross section perpendicular to the axis A is circular. Thus, the conductor body 24 and the bulge portion 25 are each formed in a columnar or cylindrical shape, and the bulge portion 25 protrudes in a ring shape from the outer circumferential surface of the conductor body 24. In other words, the bulge portion 25 has a larger diameter than the conductor body 24.

[0018] In the radial direction of the conductor body 24, the bulge portion 25 protrudes by a bulge distance d from the outer peripheral surface of the conductor body 24. The bulge distance d is the protruding height of the bulge portion 25 from the outer peripheral surface of the conductor body 24. The conductor body 24 has a radius r.

[0019] The bulge 25 has a first side surface 25a closer to the spacer body 22, a second side surface 25b farther from the spacer body 22, and an outer peripheral surface 25c connecting the first side surface 25a and the second side surface 25b. A convex curved surface 25d is formed at the boundary between the first side surface 25a and the outer peripheral surface 25c, and a convex curved surface 25e is formed at the boundary between the second side surface 25b and the outer peripheral surface 25c. In this way, the surfaces between the first side surface 25a and the second side surface 25b and the outer peripheral surface 25c are convexly curved and not sharp, which can reduce electric field concentration.

[0020] Between the first side surface 25a of the bulge 25 and the spacer body 22, a gap is provided that can appropriately alleviate the electric field intensity.

[0021] The triple point T and the maximum electric field point P in the bulge 25 in the switchgear 10 of the above embodiment are located at the positions shown in Fig. 1. The triple point T is where the spacer body 22, the central conductor 21, and the insulating gas G sealed in the sealed container 12 overlap. The maximum electric field point P is at or near the point on each side surface 25a, 25b and the outer peripheral surface 25c of the bulge 25 that is closest to the point where the electric field strength of the spacer body 22 is low.

[0022] In the above embodiment, an electric field analysis was performed on the triple point T and the maximum electric field point P. The results are shown in the graphs of Figures 2 and 3. The electric field analysis was performed while changing the condition of the bulge distance d of bulging portion 25 and keeping the other conditions the same.

[0023] An example of the electric field analysis is a general three-dimensional electric field analysis using the finite element method (FEM), and the electric field analysis can be performed using, for example, commercially available simulation software. Note that the electric field analysis is not limited to a specific method, and for example, the electric field analysis can be performed using a method such as a differential method or a surface charge method.

[0024] Fig. 2 is a graph showing the analysis results of the maximum electric field strength at the triple junction versus the proportion of the bulge distance. In the graph of Fig. 2, the vertical axis is the maximum electric field strength at the triple junction T, in units of kVpeak / mm. The horizontal axis is the proportion of the bulge distance d of the bulging portion 25 versus the radius r of the conductor body 24 (hereinafter referred to as the "proportion of the bulge distance d"), which is a relative value (%) of the bulge distance d when the radius r of the conductor body 24 is taken as 100% (see formula 1 below). In the conventional structure, the proportion of the bulge distance d is 20.4%. Ratio of bulge distance d = bulge distance d × 100 / radius r of conductor body 24 (Equation 1)

[0025] 2, the maximum electric field strength at the triple point T is roughly the same when the ratio of the bulge distance d is in the range of 5.1% to 20.4%, but increases rapidly when the ratio of the bulge distance d is smaller than 5.1%. Therefore, in order to mitigate the maximum electric field strength at the triple point T, the ratio of the bulge distance d is set to 5.1% or more.

[0026] Fig. 3 is a graph showing the analysis results of the electric field strength at the maximum electric field point versus the proportion of the bulge distance. In the graph of Fig. 3, the vertical axis is the electric field strength at the maximum electric field point P in the bulge 25, in units of kVpeak / mm, and the horizontal axis is the proportion of the bulge distance d, which is the same as the graph of Fig. 2.

[0027] As shown in the graph of Fig. 3, it has become clear that the electric field strength at the maximum electric field point P gradually decreases as the proportion of the bulge distance d decreases within the range of the proportion of the analyzed bulge distance d. Therefore, in order to reduce the electric field strength at the maximum electric field point P, the proportion of the bulge distance d is set to 20% or less, compared to the conventional structure (proportion of the bulge distance d is 20.4%). Note that, in order to better reduce the electric field strength at the maximum electric field point P, it is preferable to set the proportion of the bulge distance d to 15.3% or less, and it is more preferable to set the proportion of the bulge distance d to 10.2% or less.

[0028] According to the above embodiment, the proportion of the bulge distance d in the high voltage conductor 14 is set to 20% or less, so that the diameter of the bulge portion 25 can be made smaller than that of the conventional structure. By reducing the diameter of the bulge portion 25, the distance between the maximum electric field point P of the bulge portion 25 and the spacer body 22 can be increased, so that the electric field strength at the maximum electric field point P can be reduced. Moreover, the proportion of the bulge distance d is set to 5.1% or more, so that the increase in the electric field strength near the triple point T can be suppressed. As a result, both the electric field strength at the maximum electric field point P of the bulge portion 25 and the maximum electric field strength at the triple point T can be reduced effectively, and thus the insulation reliability can be maintained well.

[0029] Here, a heat dissipating paint may be applied to each side surface 25a, 25b and outer peripheral surface 25c of bulging portion 25 located on the concave surface R side of spacer body 22 (shown by dots in FIG. 1). Such heat dissipating paint is a coating agent that utilizes thermal radiation, and when applied to outer peripheral surface 25c of bulging portion 25, etc., it acts to lower the temperature inside bulging portion 25. Therefore, since the application of the heat dissipating paint makes it possible to suppress the temperature rise of bulging portion 25, the volume of bulging portion 25 can be reduced by the amount of suppression of such temperature rise, and the bulging distance d can be reduced.

[0030] The heat dissipation paint is composed of binder, filler (color pigment and extender pigment), various additives, and solvent, and components other than the solvent are formed as a coating on the outer peripheral surface 25c of the bulge 25. As an example of the binder, straight silicone resin can be used. As an example of the color pigment that serves as the filler, carbon black can be used. As an example of the additives and solvents, the same ones as those used in general paints can be used.

[0031] The present invention is not limited to the above-mentioned embodiment, and can be modified in various ways. In the above-mentioned embodiment, the size, shape, orientation, etc. shown in the attached drawings are not limited to these, and can be modified as appropriate within the scope of the effects of the present invention. In addition, the present invention can be modified as appropriate without departing from the scope of the purpose of the present invention.

[0032] Although the above-mentioned heat-dissipating paint has been described as being applied to the bulge 25 located on the concave surface R side of the spacer body 22, this is not limited to this, and the heat-dissipating paint may be applied to each of the bulges 25 on both sides of the central conductor 21, or may be applied to the conductor body 24.

[0033] Furthermore, the shape of the spacer body 22 is not limited to a cone shape, but may be another shape, such as a disk shape having substantially smooth surfaces on both sides in the thickness direction. [Explanation of symbols]

[0034] 10: Switchgear 12: Sealed container 13: Insulating spacer 14: High voltage conductor 21: Center conductor 22: Spacer body 24: Conductor body 25: Bulge 25a: 1st side 25b: 2nd side 25c: Outer surface 25d: Convex curved surface 25e: Convex curved surface d: Bulge distance r: Radius of the conductor body

Claims

1. A sealed container; an insulating spacer fixed inside the sealed container; A gas-insulated switchgear including: a high-voltage conductor disposed on both sides of a center of the insulating spacer, the insulating spacer includes a central conductor connected to the high voltage conductor, and a spacer body provided around the central conductor; The high voltage conductor includes a conductor body extending in a longitudinal direction, a bulge formed in the conductor body near an outer circumferential surface of the spacer body, the conductor body and the bulge are provided on the same central axis and each have a circular cross section perpendicular to the central axis, The bulge portion protrudes in a radial direction of the conductor body by a bulge distance, A gas-insulated switchgear, characterized in that a ratio of the bulge distance to a radius of the conductor body is set to 5.1% or more and 20% or less.

2. The bulge portion has a first side surface close to the spacer body; a second side surface remote from the spacer body; an outer circumferential surface connecting the first side surface and the second side surface, 2. The gas-insulated switchgear according to claim 1, wherein the first side surface and the second side surface are connected to the outer circumferential surface by convex curved surfaces.

3. 3. The gas-insulated switchgear according to claim 2, wherein a heat dissipating paint is applied to the first side surface, the second side surface and the outer circumferential surface of the bulging portion.

4. 4. The gas-insulated switchgear according to claim 1, wherein the spacer body is formed in a cone shape having an axial direction identical to that of the central conductor.

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