WO2022054154A1

WO2022054154A1 - Gas-insulated device

Info

Publication number: WO2022054154A1
Application number: PCT/JP2020/034054
Authority: WO
Inventors: 繁和森; 孝倫安岡; 好一保科
Original assignee: 東芝エネルギーシステムズ株式会社
Priority date: 2020-09-09
Filing date: 2020-09-09
Publication date: 2022-03-17
Also published as: JPWO2022054154A1; JP7400113B2

Abstract

Provided is a gas-insulated device in which size reduction and insulation reliability can be improved by suppressing the degradation of surface withstand voltage performance of an epoxy composite when using a filler having a high dielectric constant as a constituent material of an insulation support body.　The gas-insulated device according to an embodiment has a metal container, a high voltage conductor, and an insulation support body. The metal container is a cylindrical container in which an insulation gas is sealed. The high voltage conductor is housed inside the metal container so as to be separated from the inner surface of the metal container. The insulation support body is disposed between the metal container and the high voltage conductor and supports the high voltage conductor inside the metal container. The insulation support body has: a base substance formed by filling an epoxy resin with a filler; and an insulation layer for covering the surface of the base substance. The filler includes a high dielectric constant material consisting of at least one kind of barium titanate, strontium titanate, and calcium titanate. The insulation layer uses an insulation material not including the high dielectric constant material.

Description

Gas insulation equipment

The embodiment of the present invention relates to a gas insulating device.

Currently, in high-voltage and large-capacity power systems, gas insulation equipment (gas insulation switchgear: GIS) using SF ₆ (sulfur hexafluoride) gas is widely used as an isolation medium for insulation and arc discharge. .. In the gas insulating bus (GIB) constituting such a gas insulating device, for example, SF ₆ gas (insulating gas) is sealed inside a cylindrical metal container, and a high voltage conductor for energization is inserted in the center of the metal container. It has a coaxial cylindrical structure. In order to insulate and support the high voltage conductor in the metal container, an insulating spacer (insulation support) is attached between the inside of the metal container and the high voltage conductor, and an electric field is installed between the insulating spacer and the high voltage conductor. A relaxation shield is formed.

Generally, the insulating spacer constituting the gas insulating device is manufactured by mold molding using a resin in which a filler such as alumina or silica is mixed with an epoxy resin. The electric field distribution near the insulating spacer, which is an important factor in determining the size of such a gas insulating bus, depends on the geometric shape of the high voltage conductor, the insulating spacer, and the electric field relaxation shield, and the dielectric constant of the insulating spacer and the insulating gas. It is determined.

For gas-insulated buses, reducing the maximum electric field value on the surface of the insulating spacer is the most important for improving the performance and making the gas-insulated equipment compact. Therefore, conventionally, attempts have been made to optimize the shape of the insulating spacer and to reduce the dielectric constant of the insulating spacer. If the dielectric constant of the insulating spacer can be spatially changed, the electric field can be reduced, so that the gas insulating equipment can be made compact and the manufacturing cost of the gas insulating equipment due to the compactification can be reduced.

Conventionally, when the insulating spacer is manufactured by mold molding, a plurality of materials in which the blending amounts of the epoxy resin and the filler are changed stepwise are prepared, and these materials are sequentially injected into the mold to obtain an epoxy resin. And a method of heat-molding an insulating spacer by changing the ratio of the blending amount of the filler stepwise is known.

Further, there is also known an insulating spacer capable of spatially changing the dielectric constant of the insulating spacer by using a non-linear dielectric constant material whose relative permittivity increases as the electric field becomes high as a constituent material of the insulating spacer.

As described above, the epoxy resin can be used in either the case where a high dielectric constant portion is locally formed as the insulating spacer constituting the gas insulating device or the case where the non-linear dielectric constant material is used as the constituent material of the insulating spacer. It has been proposed to fill with a filler having a high dielectric constant (relative permittivity of about 100 to several thousand) such as barium titanate and strontium titanate.

However, as described above, in the configuration in which an epoxy resin is filled with a filler having a high dielectric constant such as barium titanate or strontium titanate as an insulating spacer, when a metallic foreign substance adheres to the surface thereof, the conventional epoxy composite material is used. It was found that the creepage insulation performance was significantly reduced in comparison.

As an example, a simulated experiment when a metal foreign substance adheres to the insulating spacer will be described. FIG. 4 shows the measurement results of the creepage fracture electric field of the epoxy composite material to which the metal foreign matter is attached. The atmosphere gas is SF ₆ gas. In FIG. 4, what is described as a conventional material is an epoxy composite material in which an epoxy resin is filled with alumina having a particle size distribution in the range of several μm to several tens of μm at a filling rate of 44% by volume. Further, what is described as barium titanate is an epoxy composite material in which barium titanate having a particle size of 0.5 μm is filled in an epoxy resin at a ratio of 20 vol%. The vertical axis of FIG. 4 is a creeping fracture electric field when a metal foreign substance is attached to the surface of the epoxy composite material. According to the results shown in FIG. 4, it can be seen that the creepage fracture electric field of the epoxy composite material containing barium titanate is reduced by 20% or more as compared with the epoxy composite material containing alumina (conventional material).

Due to the characteristics of the manufacturing process, it is difficult for gas insulating equipment to avoid the entry of minute metallic foreign substances. This metallic foreign matter adheres to the insulating spacer and deteriorates the creeping insulation performance of the spacer. Therefore, it is required to minimize the deterioration of creepage insulation performance when metal foreign matter adheres to the insulating spacer.

As a configuration that can prevent deterioration of creeping insulation performance even if metallic foreign matter adheres to the insulating spacer using epoxy resin, the epoxy resin is made of a fluororesin-based material with a lower dielectric constant than the epoxy resin that is the constituent material of the insulating spacer. A configuration that coats the surface is known.

However, when a fluororesin-based material is used together with the epoxy resin as a part of the constituent material of the insulating spacer, the coating made of the fluororesin-based material is peeled off due to a difference in thermal expansion coefficient from the epoxy resin, and the insulating property is deteriorated. There is.

Japanese Unexamined Patent Publication No. 2010-176969 Japanese Unexamined Patent Publication No. 2013-176275 Japanese Unexamined Patent Publication No. 2017-060209 Japanese Unexamined Patent Publication No. 06-153342

The problem to be solved by the present invention is to suppress deterioration of the creepage withstand voltage performance of the epoxy composite material when a filler having a high dielectric constant is used as a constituent material of the insulating support, thereby improving the miniaturization and insulation reliability. It is to provide gas insulation equipment which can be made.

The gas insulating device of the embodiment has a metal container, a high voltage conductor, and an insulating support. The metal container has a cylindrical shape in which an insulating gas is sealed. The high voltage conductor is housed inside the metal container so as to be separated from the inner surface of the metal container. The insulating support is arranged between the metal container and the high voltage conductor and supports the high voltage conductor inside the metal container. The insulating support has a substrate in which an epoxy resin is filled with a filler, and an insulating layer that covers the surface of the substrate. The filler contains a high dielectric constant material composed of at least one of barium titanate, strontium titanate, and calcium titanate. As the insulating layer, an insulating material that does not contain the high dielectric constant material is used.

The cross-sectional schematic diagram which shows the gas insulation apparatus of 1st Embodiment. The cross-sectional schematic diagram which shows the gas insulation apparatus of 2nd Embodiment. The graph which shows the verification result of 1st Embodiment. The graph which shows the result of having compared the creepage fracture electric field of the epoxy composite material which adhered the metal foreign matter. The graph which shows the relationship between the epoxy coating thickness and the reduction rate of the maximum electric field.

Hereinafter, the gas insulating device of the embodiment will be described with reference to the drawings. In the drawings used in the following description, in order to make the features of the embodiment easy to understand, the main parts may be enlarged and shown, and the dimensional ratios of the respective components are the same as the actual ones. Not necessarily.

(First Embodiment)
FIG. 1 is a schematic cross-sectional view showing the gas insulating device of the first embodiment.
The gas insulating device (gas insulated switchgear) 10 of the first embodiment has a hollow cylindrical metal container 11, for example, a cylindrical metal container 11. The metal container 11 is electrically grounded. The inside of the metal container 11 has an airtight structure, and the insulating gas G is sealed inside. As the insulating gas G, a gas having high insulating property, inertness, and high thermal conductivity is used. In this embodiment, sulfur hexafluoride (SF ₆ ) is used as the insulating gas G. Sulfur hexafluoride is widely used as a typical insulating gas in the fields of electrical and electronic devices.

Inside the metal container 11, a high voltage conductor 12 is housed so as to be separated from the inner surface 11a of the metal container 11. The high voltage conductor 12 is made of a metal having a high conductivity such as copper or aluminum, and extends along the central axis direction of the metal container 11.

The high voltage conductor 12 is supported inside the metal container 11 by the insulating support 13. That is, the insulating support 13 is arranged between the metal container 11 and the high voltage conductor 12, and supports the high voltage conductor 12 inside the metal container 11. In the present embodiment, the insulating support 13 is a disk-shaped member having an opening 13a in the center.

The insulating support (insulating spacer) 13 has a disk-shaped substrate 14 having an opening 13a in the center, and an insulating layer 15 that covers one side and the other side of the surface of the substrate 14. .. The substrate 14 is mainly composed of an epoxy resin and is filled (dispersed) with a filler.

Examples of the epoxy resin used for the substrate 14 include bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak type epoxy resin, and glycidylamine type epoxy resin. The bisphenol A type epoxy resin, which is a typical epoxy resin, is a copolymer of bisphenol A and epichlorohydrin, and various polyamines and acid anhydrides are used as the curing agent.

A high dielectric constant material (non-linear dielectric constant material) is used as the filler filled in the epoxy resin. The high dielectric constant material (non-linear dielectric constant material) has a relative permittivity of about 100 to several thousand, and has a characteristic that the relative permittivity increases as the electric field increases. The filler is selected from at least one or a plurality of barium titanate, strontium titanate, and calcium titanate.

As described above, the substrate 14 is an epoxy composite material containing the above-mentioned filler in the epoxy resin in an amount of, for example, about 20% by volume to 30% by volume. The ratio of the epoxy resin and the filler can be any ratio as long as appropriate non-linear dielectric properties can be obtained.

The insulating layer 15 constituting the insulating support 13 is made of an insulating material that does not contain a high dielectric constant material that is a filler filled in the epoxy resin. For example, the insulating layer 15 is formed in a range of more than 50 μm and 5 mm or less in thickness so as to cover the surface of the substrate 14. By setting the thickness of the insulating layer 15 to more than 50 μm, even if metal foreign matter adheres to the insulating support 13, there is no possibility that the insulating performance is significantly deteriorated. Further, if the thickness of the insulating layer 15 exceeds 5 mm, the size of the insulating support 13 becomes large and the request for compactification of the gas insulating device 10 cannot be satisfied. Therefore, the thickness of the insulating layer 15 is preferably 5 mm or less. The thickness of the insulating layer 15 may be 100 μm or more, or 150 μm or more.

An example of the constituent material of the insulating layer 15 is a resin material using epoxy as a base material. The resin material using epoxy as a base material here includes all thermosetting resins having a crosslinked structure with epoxy groups remaining in the polymer. In the present embodiment, the insulating layer 15 is composed of, for example, only a bisphenol A type epoxy resin.

Further, in addition to the above-mentioned epoxy resin and filler which is a high dielectric constant material, the substrate 14 can be further filled with alumina or silica as a filler. By adding alumina or silica as a filler, the mechanical properties, for example, strength of the epoxy composite material constituting the substrate 14 can be improved.

Electric field relaxation shields (electric field relaxation rings) 16 are formed on both side portions where the high voltage conductor 12 is in contact with the insulating support 13. The electric field relaxation shield 16 includes, for example, a base material made of metal and an insulating portion provided on the surface of the base material.

According to the gas insulating device 10 having the above configuration, the substrate in which the epoxy resin is filled with a filler made of a high dielectric constant material (non-linear dielectric constant material) as the insulating support 13 for supporting the high voltage conductor 12. The surface of 14 was covered with an insulating layer 15 made of an insulating material containing no high dielectric constant. As a result, even if metallic foreign matter that is inevitably generated in the manufacture of the gas insulating device 10 adheres to the insulating support 13, the surface of the substrate 14 is covered with the insulating layer 15 that does not contain the high dielectric constant material. Therefore, the metal foreign matter does not come into contact with the high dielectric constant material contained in the substrate 14.

Therefore, it is possible to prevent the creepage withstand voltage performance from being deteriorated due to the contact of the metal foreign matter with the high dielectric constant material, and even when the gas insulation device 10 is applied to the gas insulation switchgear, sufficient withstand voltage performance can be obtained. Can be maintained.

Further, according to the gas insulating device 10 of the present embodiment, if the insulating layer 15 constituting the insulating support 13 is formed of a resin material using epoxy as a base material, a filler which is a high dielectric constant material can be added to the epoxy resin. Since the bondability between the filled substrate 14 and the filled substrate 14 due to the epoxy-based material is enhanced, it is possible to prevent the insulating layer 15 from peeling off from the substrate 14. It is possible to prevent the insulating layer 15 from being peeled off due to aging and the filler of the substrate 14 to be exposed, and the creeping insulation performance from being deteriorated due to the adhesion of metal foreign matter.

Then, since the substrate 14 of the insulating support 13 is made of an epoxy composite material in which an epoxy resin is filled with a filler made of a high dielectric constant material (non-linear dielectric constant material), the ratio is such that the electric field of the insulating support 13 becomes high. The dielectric constant increases. As a result, the maximum electric field value on the surface of the insulating support 13 can be reduced, and the gas insulating device 10 can be made compact.

As described above, according to the gas insulating device 10 of the present embodiment, the withstand voltage performance is prevented from being deteriorated due to metal foreign matter to improve the insulation reliability, and the maximum electric field value on the surface of the insulating support 13 is reduced. It is possible to make the gas insulation device 10 compact at the same time.

(Second Embodiment)
FIG. 2 is a schematic cross-sectional view showing the gas insulating device of the second embodiment.
The same number is assigned to the same configuration as in the first embodiment, and the description of the overlapping configuration will be omitted.
The gas insulating device (gas insulated switchgear) 20 of the second embodiment has an insulating support 23 that supports the high voltage conductor 12. In the insulating support 23, the surface of the substrate 24 in which the epoxy resin is filled with a filler made of a high dielectric constant material is covered with an insulating layer 25 made of an insulating material containing no high dielectric constant material. The filler is selected from at least one or a plurality of barium titanate, strontium titanate, and calcium titanate. As an example of the constituent material of the insulating layer 25, a resin material having an epoxy as a base material can be mentioned as in the insulating layer 15 of the first embodiment.

In the substrate 24 of the present embodiment, the filling concentration of the high dielectric constant material for the epoxy resin is higher on the high voltage conductor 12 side (center side) than on the metal container 11 side (outer peripheral side) of the insulating support 23. It is distributed in an inclined manner. Such a change in the packing concentration of the high dielectric constant material may be stepwise or stepless. The minimum filling concentration of the high dielectric constant material on the metal container 11 side (outer peripheral side) is preferably in the range of 0 to 10% by volume. On the other hand, the maximum filling concentration of the high dielectric constant material on the high voltage conductor 12 side (center side) is preferably in the range of 25 to 30% by volume. Then, the filling concentration of the high dielectric constant material may be increased steplessly from the outer peripheral side to the inner peripheral side even if it is stepwise.

For the substrate 24 in which the filling concentration of the high-dielectric-constant material with respect to the epoxy resin is changed, for example, an epoxy resin pre-filled with the high-dielectric-constant material having a plurality of concentrations is prepared, and the high-voltage conductor 12 side (center side) is prepared. ) To the metal container 11 side (outer peripheral side) so that the filling concentration of the high dielectric constant material decreases, the epoxy resin is injected into the mold and then cured.

According to the gas insulating device 20 of the present embodiment, as the insulating support 23 for supporting the high voltage conductor 12, the substrate 24 is filled with a filler made of a high dielectric constant material (non-linear dielectric constant material) in an epoxy resin. The surface was covered with an insulating layer 25 made of an insulating material containing no high dielectric constant material. As a result, even if metallic foreign matter that is inevitably generated in the manufacture of the gas insulating device 20 adheres to the insulating support 23, the surface of the substrate 24 is covered with the insulating layer 25 that does not contain the high dielectric constant material. Therefore, the metal foreign matter does not come into contact with the high dielectric constant material contained in the substrate 24.

Therefore, it is possible to prevent the creepage withstand voltage performance from being deteriorated due to the contact of the metal foreign matter with the high dielectric constant material, and even when the gas insulation device 20 is applied to the gas insulation switchgear, sufficient withstand voltage performance can be obtained. Can be maintained.

Further, according to the gas insulating device 20 of the present embodiment, if the insulating layer 25 constituting the insulating support 23 is formed of a resin material using epoxy as a base material, a filler which is a high dielectric constant material can be added to the epoxy resin. Since the bondability between the filled substrate 24 and the filled substrate 24 due to the epoxy-based material is enhanced, it is possible to prevent the insulating layer 25 from peeling off from the substrate 24. It is possible to prevent the insulating layer 25 from being peeled off due to aging and the filler of the substrate 24 to be exposed, and the creeping insulation performance from being deteriorated due to the adhesion of metallic foreign matter.

On the other hand, the substrate 24 of the insulating support 23 uses an epoxy composite material in which a high dielectric constant material is filled in the epoxy resin so that the filling concentration decreases from the high voltage conductor 12 side toward the metal container 11 side. Therefore, the high dielectric constant material is filled with a filling concentration corresponding to the strength of the electric field strength of the insulating support 23, and the maximum electric field value on the surface of the insulating support 23 can be efficiently reduced. It can be made compact.

As described above, according to the gas insulating device 20 of the present embodiment, the withstand voltage performance is prevented from being deteriorated due to metal foreign matter to improve the insulation reliability, and the maximum electric field value on the surface of the insulating support 23 is reduced. It is possible to achieve both compactness of the gas insulating device 20.

According to at least one embodiment described above, the insulating support has a substrate in which an epoxy resin is filled with a filler and an insulating layer for covering the surface of the substrate, and the filler is a high dielectric constant material. By using an insulating material that does not contain a high dielectric constant as the insulating layer, even if metal foreign matter that is inevitably generated in the manufacture of gas insulating equipment adheres to the insulating support, the insulating support It is possible to provide a gas insulating device capable of suppressing deterioration of the creepage withstand voltage performance of an epoxy composite material when a filler having a high dielectric constant is used as a constituent material, and improving miniaturization and insulation reliability.

In each of the above-described embodiments, the insulating support (insulating spacer) is formed in a disk shape, but in addition to this, for example, the insulating support may be formed in a cone shape or a post (pillar) shape. You can also. The shape of the insulating support is not limited to the shape of each of the above-described embodiments.

The optimum range of the thickness of the insulating layer in the gas insulating device of the embodiment was verified. Barium titanate (particle size 0.5 μm, packing concentration 20 vol%) was used as the high dielectric constant material (non-linear dielectric constant material) of the filler to be filled in the epoxy resin of the substrate. Sulfur hexafluoride (SF ₆ ) was used as the insulating gas to be sealed in the metal container. An insulating support (insulating spacer) was formed by coating an insulating layer made of epoxy resin on the surface of a substrate made of an epoxy composite material in which barium titanate was filled in such an epoxy resin. The film thickness of the insulating layer was 50 μm and 150 μm. Further, as a comparative example, an insulating support was formed in which the surface of the substrate was not covered with the insulating layer. FIG. 3 shows the results of measuring the creepage fracture electric field when a metal foreign substance is attached to these three samples.

According to the verification results shown in FIG. 3, when the coating thickness of the insulating layer is 150 μm, the creepage fracture electric field is improved to the same level as that of the conventional epoxy composite material using alumina as the filler (see the dotted line in FIG. 4). The result was obtained. On the other hand, when the coating thickness of the insulating layer was 50 μm, no improvement in the creepage fracture electric field was observed. At least, in order to improve the creepage fracture electric field, it is considered that a coating thickness of more than 50 μm, preferably 100 μm or more is required.

The upper limit of the coating thickness of the insulating layer is described. If the epoxy coating is too thick, the nonlinear dielectric will move away from the solid / gas interface. In this case, since the electric field relaxation effect at the boundary portion is weakened, it is necessary to set an upper limit of the coating thickness. FIG. 5 shows an example of analyzing the relationship between the epoxy coating thickness (thickness of the insulating layer) on the surface of the nonlinear dielectric material and the rate of decrease in the maximum electric field at the epoxy / gas boundary portion (electric field relaxation effect). From FIG. 5, it can be seen that when the epoxy coating thickness is 20 mm or more, the reduction rate of the maximum electric field is 10% or less, and the electric field relaxation effect is weakened. If a non-linear dielectric material is used and the maximum electric field relaxation effect is expected, it is appropriate that the upper limit of the epoxy coating thickness is several mm or less, and 5 mm or less is recommended.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and variations thereof are included in the scope of the invention described in the claims and the equivalent scope thereof, as are included in the scope and gist of the invention.

10, 20 ... Gas insulation equipment (gas insulation switchgear), 11 ... Metal container, 12 ... High voltage conductor, 13, 23 ... Insulation support, 14, 24 ... Base, 15, 25 ... Insulation layer, 16 ... Electricity relaxation shield.

Claims

A tubular metal container filled with an insulating gas, a high-voltage conductor housed inside the metal container so as to be separated from the inner surface of the metal container, and the metal container and the high-voltage conductor. It is provided with an insulating support arranged between the metal containers to support the high voltage conductor inside the metal container.
The insulating support has a substrate in which an epoxy resin is filled with a filler, and an insulating layer that covers the surface of the substrate.
The filler contains a high dielectric constant material composed of at least one of barium titanate, strontium titanate, and calcium titanate.
The insulating layer is a gas insulating device using an insulating material that does not contain the high dielectric constant material.
The gas insulating device according to claim 1, wherein the filling concentration of the high dielectric constant material with respect to the epoxy resin is changed so as to be higher on the high voltage conductor side than on the metal container side in the insulating support. ..
The gas insulating device according to claim 1 or 2, wherein the thickness of the insulating layer is in the range of more than 50 μm and 5 mm or less.
The gas insulating device according to any one of claims 1 to 3, wherein the insulating layer is made of a resin material having an epoxy resin as a base material.
The gas insulating device according to any one of claims 1 to 4, wherein the filler further contains alumina or silica.