JP2024031261A - Insulating spacer and method for manufacturing insulating spacer - Google Patents

Abstract

[Problem] To prevent a manufacturing device from becoming large-scale. An insulating spacer (3) includes a disk-shaped spacer body (12) that supports a center conductor (11) and is provided around the center conductor. The spacer body is formed with a relative dielectric constant that changes in the radial direction. The spacer body is constructed by winding a tape-shaped prepreg (P) around a central conductor and integrating the prepreg (P). The prepreg has a region in which the dielectric constant gradually increases or decreases in the longitudinal direction, and for example, the dielectric constant changes smaller as the distance from the center conductor increases. [Selection diagram] Figure 1

Description

There is an application for exception to loss of novelty.

The present invention relates to an insulating spacer, and particularly to an insulating spacer used in a gas-insulated switchgear and a method for manufacturing an insulating spacer.

Gas-insulated switchgear has a structure in which a high-voltage conductor is placed in a metal sealed container. In such a gas-insulated switchgear, a solid insulator called an insulating spacer is used to fix the high-voltage conductor at a predetermined position in a sealed container.

Conventionally, in a generally used disc-shaped insulating spacer, a high voltage conductor is provided in the center, and the insulating spacer is provided so as to support the high voltage conductor. A metal flange is attached around the insulating spacer, and is fixed to the sealed container by being sandwiched between the connecting flanges of the sealed container.

In recent years, more economical efficiency has been required, and it is desired that gas insulated switchgears be made more compact. In conventional insulating spacers, the electric field concentration in the gas space caused by the difference in dielectric constant between the insulating gas mainly composed of SF ₆ and the solid insulator is an obstacle to miniaturization. Therefore, in order to achieve compactness, studies have been conducted to reduce the electric field component in the creeping direction of the surface by changing the dielectric constant of the disc-shaped insulating spacer in the radial direction (see, for example, Patent Document 1).

Patent Document 1 discloses an integral insulator whose dielectric constant is sloped such that the dielectric constant decreases from a portion that contacts a high-voltage conductor toward the ground side. In Patent Document 1, in order to manufacture such an insulator, an inorganic filler-filled resin is injected into a mold having a disc-shaped cavity, and then the mold is rotated. Due to the rotation of the mold, centrifugal force is applied to the resin filled with inorganic filler from the center of the cavity toward the outside, resulting in an insulator whose dielectric constant decreases from the center of the insulator toward the outside.

Japanese Patent Application Publication No. 2004-273394

However, in Patent Document 1, in order to apply centrifugal force to the inorganic filler-filled resin injected into the mold, it is necessary to rotate the mold weighing tens to hundreds of kilograms. Therefore, in order to ensure the durability and stable operation of the equipment, there is a problem in that the equipment has to be large-scale.In particular, when the insulator is increased in size, it is necessary to rotate the mold and support the rotating mold. There is a problem in that it becomes impractical to prepare the equipment.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an insulating spacer and a method for manufacturing an insulating spacer that can prevent the manufacturing apparatus from becoming large-scale.

An insulating spacer according to one embodiment of the present invention includes a disc-shaped spacer body that supports a center conductor and is provided around the center conductor, and has a dielectric constant that changes in the radial direction of the spacer body. The spacer body is characterized in that it is constructed by winding a tape-shaped prepreg around the center conductor and integrating it.

A method for manufacturing an insulating spacer according to one embodiment of the present invention includes a disk-shaped spacer body that supports a center conductor and is provided around the center conductor, and an insulator whose relative dielectric constant changes in the radial direction of the spacer body. A method for manufacturing a spacer, comprising a prepreg manufacturing step of manufacturing a prepreg formed into a tape shape and having a region whose dielectric constant gradually increases or decreases in the longitudinal direction; and after the prepreg manufacturing step, the prepreg is The present invention is characterized in that a winding step is performed in which the spacer body is formed by winding the center conductor, and an unifying step is performed in which the wound prepreg is brought into an integrated state after the winding step.

According to the present invention, since the spacer body can be formed by winding the tape-shaped prepreg, it is possible to eliminate the step of injecting a resin material into a mold in manufacturing the insulating spacer. As a result, the dielectric constant is changed in the radial direction of the spacer body, so a device or equipment for rotating a mold injected with resin material is not required, and the device can be prevented from becoming bulky. Furthermore, if the diameter of the spacer body increases, this can be handled by increasing the number of times the prepreg is wound, and this also makes it possible to avoid using a large-scale device.

It is a sectional view of the opening and closing device concerning an embodiment. FIG. 2 is a schematic plan view of prepreg. FIG. 3A is an explanatory diagram of the initial stage of the winding process, FIG. 3B is an explanatory diagram of the intermediate stage of the winding process, and FIG. 3C is an explanatory diagram of the winding process and the integrating process. FIGS. 4A and 4B are graphs for explaining an exemplary configuration of an insulating spacer. FIGS. 5A and 5B are graphs for explaining another exemplary configuration of the insulating spacer.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a gas insulated switchgear (hereinafter simply referred to as a "switcher") in which an insulating spacer according to an embodiment of the present invention is used will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments described below, and can be implemented with appropriate modifications within the scope without changing the gist thereof. In the following figures, some configurations may be omitted for convenience of explanation.

FIG. 1 is a sectional view of a switchgear according to an embodiment. As shown in FIG. 1, the switchgear 1 includes a sealed container 2, an insulating spacer 3 fixed inside the sealed container 2, and high-voltage conductors 4 (indicated by two-dot chain lines) arranged on both sides of the center of the insulating spacer 3. (as shown).

A metal flange 6 is attached to the outer peripheral edge of the insulating spacer 3. The metal flange 6 is sandwiched between the connecting flanges 7 of the sealed container 2, and the insulating spacer 3 is attached to the sealed container 2 with bolts 8 and nuts 9. Fixed.

The insulating spacer 3 includes a central conductor 11 having a shaft shape and a spacer body 12 provided around the central conductor 11. In this embodiment, the spacer main body 12 is formed into a disk shape, and both surfaces in the vertical direction in FIG. 1, which is the thickness direction, are substantially smooth. In the insulating spacer 3 , the center conductor 11 is supported by the spacer body 12 at the center of the sealed container 2 and at the center of the spacer body 12 .

The center conductor 11 is formed into a roughly cylindrical shape, and the ends of the high voltage conductor 4 are connected to both upper and lower ends in FIG. 1 via a screw structure or the like. In this embodiment, the axial length of the center conductor 11 is larger than the thickness of the spacer body 12, and both upper and lower ends of the center conductor 11 are formed to protrude from both upper and lower surfaces of the spacer body 12 in FIG. There is.

The spacer body 12 has a configuration in which the dielectric constant changes (inclines) in the radial direction. Here, in FIG. 1 and FIG. 2 to be described later, relative changes in relative dielectric constant are expressed in shading for easy understanding.More specifically, regions that are relatively light in color are This indicates that the relative dielectric constant is higher than that of the dark-colored region. Therefore, in the spacer body 12, the region closer to the center conductor 11 shown in light color has a higher dielectric constant than the region closer to the outer periphery shown in dark color.In other words, the relative permittivity decreases as the distance from the center conductor 11 increases. The configuration is such that the change is small. In order to have such a configuration, the spacer main body 12 is constructed by winding a plurality of tape-shaped (band-shaped) prepregs P, which will be described later, around the center conductor 11 and integrating them.

Next, a method for manufacturing the insulating spacer 3 including the spacer body 12 will be described below with reference to FIGS. 2 and 3. FIG. 2 is a schematic plan view of the prepreg. FIG. 3A is an explanatory diagram of the initial stage of the winding process, FIG. 3B is an explanatory diagram of the intermediate stage of the winding process, and FIG. 3C is an explanatory diagram of the winding process and the integrating process. In the method for manufacturing the insulating spacer 3 in this embodiment, the prepreg manufacturing process, the winding process, and the integrating process are performed in this order. Moreover, here, as an example, a method of manufacturing a structure in which the dielectric constant of the spacer body 12 changes as shown in FIG. 1 will be described.

First, as shown in FIG. 2, a prepreg manufacturing process is performed. In the prepreg manufacturing process, a prepreg P extending in a tape shape in the longitudinal direction is formed. The thickness of the prepreg P is formed to be approximately 50 to 100 μm. The prepreg P includes a nonwoven fabric (not shown) as a base material, and is formed by coating and impregnating the nonwoven fabric with an insulating resin containing a filler (inorganic filler) using a coater or the like. The insulating resin is made into a fluid state or a semi-hardened state in this step and the next winding step, and can be composed of a thermosetting resin containing a filler.

In the prepreg manufacturing process, when forming the prepreg P into a tape shape, at least one of the composition and amount of the filler contained in the thermosetting resin is adjusted so as to provide a region where the dielectric constant gradually increases and decreases in the longitudinal direction. Ru. Specifically, in the prepreg P shown in FIG. ), the relative dielectric constant becomes gradually higher than that of In other words, the prepreg P is adjusted so that the relative dielectric constant changes smaller as the distance from the center conductor 11 increases.

After the prepreg manufacturing process, a winding process is performed. In the winding step, first, as shown in FIG. 3A, the end portion of the prepreg P having a relatively higher dielectric constant (the lighter color) in the longitudinal direction is connected to the center conductor 11. Thereafter, the center conductor 11 is rotated around the axis via a drive mechanism (not shown), and the prepreg P is wound around the center conductor 11 as shown in FIGS. 3B and 3C.

By winding the prepreg P in the winding process, a disk-shaped spacer body 12 is formed around the center conductor 11. The spacer main body 12 is formed so that the dielectric constant gradually decreases from the inside toward the outside in the radial direction. Further, the spacer main body 12 is formed by using a tape-shaped prepreg P as a resin layer and stacking a plurality of resin layers in the radial direction.

In the winding process, a pair of disk-shaped jigs J are used into which both ends of the center conductor 11 in the axial direction are inserted. When winding the prepreg P, the pair of jigs J are set to have a separation width according to the width of the prepreg P, and by winding the prepreg P, both sides of the spacer body 12 in the thickness direction are formed as smooth surfaces. I will guide you.

After the winding manufacturing process, an integration process is performed. In the integration process, the prepreg P was put into a heating furnace for a predetermined period of time in the state shown in FIG. state. As a result, the prepreg P hardens and forms the disc-shaped spacer main body 12. After curing, the pair of jigs J are removed from the center conductor 11.

Next, with reference to FIGS. 4 and 5, the configurations of the spacer main body 12 and the prepreg P will be described using a specific example. 4A and 4B are graphs for explaining a configuration as an example of an insulating spacer, and FIGS. 5A and 5B are graphs for explaining a configuration as another example of an insulating spacer. In the graphs of FIGS. 4A and 5A, the horizontal axis is the radius dimension of the spacer body and the vertical axis is the dielectric constant. In the graphs of FIGS. 4B and 5B, the horizontal axis is the prepreg length and the vertical axis is the dielectric constant. It is said that

Each of the insulating spacers 3 shown in FIGS. 4 and 5 has a configuration in which the center conductor 11 has a diameter of 100 mm, the spacer body 12 has a diameter of 400 mm, the prepreg P has a thickness of 0.5 mm, and the prepreg P has a length of 235.5 m. First, an example of the insulating spacer 3 will be described using FIGS. 4A and 4B.

As shown in FIG. 4A, the relative permittivity is 12 at the 50 mm radius position of the spacer body 12, that is, the inner edge position and the boundary position with the center conductor 11, and the relative permittivity is 12 at the outer edge position (approximately 200 mm radius position) of the spacer body 12. The dielectric constant is assumed to be 4. Here, the relative permittivity is constant from the inner edge position of the spacer main body 12 to a position with a radius of about 75 mm toward the outside in the radial direction, and the relative permittivity increases stepwise at 5 mm intervals from that position to a position with a radius of about 110 mm. It's getting smaller. Therefore, in the range from a position with a radius of about 75 mm to a position with a radius of about 110 mm of the spacer body 12, the relative permittivity changes smaller as the distance from the center conductor 11 increases. The relative permittivity is constant at 4 from the position of the radius of about 110 mm of the spacer body 12 to the outer edge position radially outward.

In order to form the change in the dielectric constant of the spacer body 12 shown in FIG. 4A, the distribution of the dielectric constant in the longitudinal direction of the prepreg P shown in FIG. 4B is set. As shown in FIG. 4B, the relative dielectric constant is set to 12 at one end of the prepreg P, which is the connection position with the center conductor 11, and the relative permittivity is set to 4 at the other end, which is the opposite side. The relative permittivity is constant at 12 up to a position of about 20 m from one end of the prepreg P, and changes so that the relative permittivity decreases stepwise from a position of about 20 m to a position of about 60 m. More specifically, the relative permittivity of the prepreg P decreases stepwise by 1 at intervals of approximately 5 m to 8 m from a position of approximately 20 m. The dielectric constant is constant at 4 from a position of about 60 m of the prepreg P to the other end.

By winding a tape-shaped prepreg P with a relative permittivity that changes in the longitudinal direction as shown in FIG. 4B, the relative permittivity changes gradually as it moves away from the center conductor 11 in the radial direction as shown in FIG. 4A. The spacer body 12 can be formed.

Next, another example of the insulating spacer 3 will be described using the graph of FIG. 5. As shown in FIG. 5A, the relative dielectric constant is 12 at the inner edge position (50 mm radius position, boundary position with the center conductor 11) and outer edge position (200 mm radius position) of the spacer body 12, and the diameter of the spacer body 12 is The dielectric constant is set to 4 at the middle part in the direction. The relative permittivity is constant from the inner edge position of the spacer body 12 to the radially intermediate position at a radius of approximately 75 mm, and the relative permittivity decreases by 1 in steps of 5 mm from that position to a position at a radius of approximately 110 mm. It has become. The relative permittivity is constant at 4 from a position with a radius of about 110 mm to a position with a radius of about 140 mm of the spacer body 12. Then, the relative dielectric constant increases stepwise by 1 every 5 mm from the position of the radius of about 140 mm to the position of the radius of about 175 mm of the spacer body 12, and from the position of the radius of about 175 mm to the outer edge position radially outward, the relative permittivity increases by 1. The dielectric constant is assumed to be constant at 12. Therefore, in the range from a position with a radius of about 75 mm to a position with a radius of about 175 mm of the spacer body 12, the relative dielectric constant changes so that it gradually decreases and then gradually increases.

In order to form the change in the dielectric constant of the spacer body 12 shown in FIG. 5A, the distribution of the dielectric constant in the longitudinal direction of the prepreg P shown in FIG. 5B is set. As shown in FIG. 5B, the dielectric constant is 12 at one end of the prepreg P where it is connected to the center conductor 11 and the other end on the opposite side, and the dielectric constant is 4 at the middle portion in the longitudinal direction. Ru. Specifically, the dielectric constant is constant at 12 from the one end of the prepreg P to a position of about 20 m, and changes so that the dielectric constant decreases stepwise from a position of about 20 m to a position of about 60 m. More specifically, the relative permittivity of the prepreg P decreases stepwise by 1 at intervals of approximately 5 m to 8 m from a position of approximately 20 m.

The dielectric constant is constant at 4 from a position of about 60 m to a position of about 108 m of the prepreg P. The relative permittivity changes stepwise from a position of about 108 m to a position of about 178 m of the prepreg P. More specifically, the relative dielectric constant of the prepreg P increases stepwise by 1 at intervals of approximately 10 m from a position of approximately 108 m. The dielectric constant is constant at 4 from a position of about 178 m of the prepreg P to the other end. In this way, in the prepreg P shown in FIG. 5B, the relative permittivity changes small in the longitudinal direction from the central conductor 11 toward the longitudinally intermediate portion, and from the longitudinally intermediate portion toward the side opposite to the central conductor 11. The dielectric constant changes significantly.

By winding a tape-shaped prepreg P with a relative permittivity that increases or decreases in the longitudinal direction as shown in FIG. 5B, the relative permittivity increases from the radial middle part toward both the inside and outside as shown in FIG. 5A. A varying spacer body 12 can be formed.

Next, the components and characteristics of the nonwoven fabric and insulating resin of the base material of the prepreg P will be explained. Paper nonwoven fabric, glass fiber nonwoven fabric, aromatic nonwoven fabric, etc. are used as the nonwoven fabric. The insulating resin is a resin having a dielectric constant of about 3 to 40, which can function as the insulating spacer 3 when heated and hardened, and is a fluid resin.

The insulating resin may specifically be a thermosetting resin containing a filler, and the thermosetting resin may be, for example, an epoxy resin, a maleimide resin, a cyanate resin, or a mixture thereof. The thermosetting resin is preferably an epoxy resin. The epoxy resin preferably includes an epoxy resin base, a curing agent, and optionally a curing accelerator. As the epoxy resin base, aliphatic epoxy, alicyclic epoxy, or a mixture thereof can be used. Examples of aliphatic epoxy resins include, but are not limited to, bisphenol A epoxy, bisphenol F epoxy, bisphenol AD epoxy, biphenyl epoxy, cresol novolak epoxy, trifunctional or higher polyfunctional epoxy, and the like. . These can be used alone or in combination of two or more. Examples of the alicyclic epoxy resin include, but are not limited to, monofunctional epoxy, bifunctional epoxy, trifunctional or more polyfunctional epoxy, and the like. The alicyclic epoxy resin can also be used alone or in a mixture of two or more different alicyclic epoxy resins.

The insulating resin may include a thermosetting resin curing agent as an optional component. The curing agent is not particularly limited as long as it reacts with the main ingredient of the thermosetting resin and can be cured. For example, as the curing agent for the epoxy resin base material, it is preferable to use an acid anhydride curing agent. Examples of acid anhydride curing agents include aromatic acid anhydrides, specifically phthalic anhydride, pyromellitic anhydride, trimellitic anhydride, and the like. Alternatively, cyclic aliphatic acid anhydrides, specifically tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, etc., or aliphatic acid anhydrides, specifically Examples include succinic anhydride, polyadipic anhydride, polysebacic anhydride, polyazelaic anhydride, etc., but are not particularly limited. The amount of the curing agent added may be the amount necessary for curing the base resin, and may be determined as appropriate by those skilled in the art, although it varies depending on the types of the base resin and the curing agent.

Further, the insulating resin may include a curing accelerator for thermosetting resin as an optional component. As the curing accelerator, imidazole or its derivatives, tertiary amines, borate esters, Lewis acids, organometallic compounds, organic acid metal salts, etc. can be used as appropriate, but are not particularly limited.

Furthermore, the insulating resin may contain optional additives within a range that does not impair its properties. Examples of additives include, but are not limited to, flame retardants, pigments for coloring resins, plasticizers and silicone elastomers for improving crack resistance. Further, a solvent may be added to the insulating resin in order to improve the impregnating property into the nonwoven fabric.

The filler is contained in the resin in a composition and amount that makes the dielectric constant of the insulating resin a desired dielectric constant. As the filler, an insulating inorganic filler can be used. As a filler for preparing an insulating resin with a relatively low dielectric constant, alumina, silica, dolomite, etc. having a relative dielectric constant of less than 10 can be used to prepare an insulating resin with a relatively high dielectric constant. Titanium oxide, barium titanate, strontium titanate, etc. can be used as the filler for the purpose, but the filler is not limited to these.

In this embodiment, the composition of the insulating resin includes a thermosetting resin base, a curing agent, optionally a curing accelerator, and an inorganic filler to achieve desired physical property values such as dielectric constant and heat resistance. A person skilled in the art can appropriately determine this. The desired relative permittivity value is preferably designed such that the ratio of the relative permittivity of the resin with the lowest relative permittivity to the resin with the highest relative permittivity is 3 to 4.

Moreover, it is preferable to design so that the difference in dielectric constant between adjacent insulating resins that are laminated by winding the prepreg P and are in contact with each other in the thickness direction is, for example, 1 or less. If the difference in dielectric constant between adjacent insulating resins is too large, there may be a problem that the electric field is concentrated on the surface of the insulating spacer 3 where there is an interface.

According to the embodiment described above, the spacer main body 12 whose dielectric constant changes in the radial direction is formed by winding the tape-shaped prepreg P. Thereby, in manufacturing the insulating spacer 3, it is possible to eliminate the need for a device or equipment for rotating a mold injected with a liquid resin material as in the past. Such devices and facilities rotate molds weighing tens to hundreds of kilograms, so they are large-scale from the viewpoint of durability and safety. However, in the above embodiment, such large-scale devices and facilities are This can be made unnecessary, reducing equipment costs and facilitating manufacturing.

Further, according to the above embodiment, by adjusting the insulating resin so that the relative permittivity changes in the longitudinal direction of the prepreg P, the relative permittivity can be changed in the radial direction of the spacer body 12. . Therefore, by designing the composition, amount, and range of the filler in the prepreg P in the longitudinal direction so as to achieve a predetermined change in the relative permittivity, various variations can be achieved in the change in the relative permittivity in the spacer body 12. You can have it. As a result, the distribution of relative dielectric constant in the spacer body 12 can be set according to the occurrence of electric field concentration under various conditions, and the electric field of the component in the creeping direction of the surface of the spacer body 12 is reduced, thereby making the switchgear 1 more compact. can be achieved.

Note that the present invention is not limited to the above embodiments, and can be implemented with various modifications. In the embodiments described above, the size, shape, orientation, etc. illustrated in the accompanying drawings are not limited to these, and can be changed as appropriate within the scope of achieving the effects of the present invention. Other changes can be made as appropriate without departing from the scope of the invention.

The change in the dielectric constant in the radial direction of the spacer body 12 illustrated and described in the above embodiment is merely an example, and various other changes in the dielectric constant can be adopted. For example, a structure may be adopted in which the relative dielectric constant changes greatly as the distance from the center conductor 11 increases, or a structure in which the relative permittivity changes small as the distance from the radial intermediate portion goes both toward the inside and outside. Further, in FIGS. 4B and 5B, the dielectric constant of the prepreg P is changed in stages, but the present invention is not limited to this, and the dielectric constant may be changed continuously according to the position in the longitudinal direction.

Further, the number of the center conductors 11 is not limited to one, but may be changed to a plurality (for example, three).

3: Insulating spacer 11: Center conductor 12: Spacer body P: Prepreg

Claims (7)

An insulating spacer comprising a disc-shaped spacer body that supports a center conductor and is provided around the center conductor, the dielectric constant changing in the radial direction of the spacer body,
The insulating spacer is characterized in that the spacer body is constructed by winding and integrating a tape-shaped prepreg around the center conductor. 2. The insulating spacer according to claim 1, wherein the prepreg includes a region in which the dielectric constant gradually increases or decreases in the longitudinal direction. 2. The insulating spacer according to claim 1, wherein the prepreg has a relative permittivity that decreases as it moves away from the center conductor in the longitudinal direction. In the longitudinal direction, the prepreg has a relative permittivity that changes small from the center conductor toward a longitudinally intermediate portion, and a relative permittivity that changes largely from the longitudinally intermediate portion toward a side opposite to the center conductor. The insulating spacer according to claim 1, characterized in that: 5. The insulating spacer according to claim 1, wherein the relative dielectric constant changes in a stepwise manner in the longitudinal direction of the prepreg. The insulating spacer according to any one of claims 1 to 4, wherein the prepreg includes a nonwoven fabric as a base material. A method for manufacturing an insulating spacer comprising a disk-shaped spacer body that supports a center conductor and is provided around the center conductor, the dielectric constant changing in the radial direction of the spacer body, the method comprising:
A prepreg manufacturing process of manufacturing a prepreg formed into a tape shape and having a region where the dielectric constant gradually increases or decreases in the longitudinal direction;
After the prepreg manufacturing step, a winding step of winding the prepreg around the center conductor to form the spacer body;
A method for manufacturing an insulating spacer, characterized in that, after the winding step, an unifying step is performed to bring the wound prepreg into an integrated state.

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