JPH11262143A - Insulation spacer and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the electric-field strength of a triple junction, relaxing the concentration of an electric field to the triple junction, by forming an insulation support of the main body portion of an insulation spacer out of an insulation member, and by providing the insulation member through winding it around the conductor-connected electrode inside it, and further, by disposing in a higher-dielectric-constant insulation member having a directric constant higher than the insulation member. SOLUTION: In a sealed container 1 made of a grounded metal which is filled with an insulation gas, a conductor 9 with an applied high-voltage is supported by an insulation support 10 via an electrode 3 connected with the conductor 9. Also, an insulation spacer 20 comprises the electrode 3 connected with the conductor 9 and the insulation supporter 10 of its main body portion which has an insulation member 7 and a higher permittivity bearing high-dielectric member 6 than the insulation member 7. As a result, since from the side close to a high-voltage conductor 2 comprising the conductor 9 and the electrode 3 to the side of a low-voltage conductor the dielectric members having sequentially step-wise lower permittivity than preceding ones are disposed to provide the gradient of the permittivity, making small the differences between the voltages shared by the respective portions, the concentrations of the electric fields to their boundary portions are relaxed to reduce the electric-field strength of a triple junction 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an insulating spacer for insulating and supporting a conductor in a grounded metal container.

[0002]

2. Description of the Related Art In a conventional gas insulating apparatus, a conductor to which a high voltage is applied is supported by an insulating support via a conductor connecting electrode in a closed metal container in which an insulating gas is sealed. (Hereinafter, an insulating component composed of a conductor connection electrode and an insulating support is defined as an insulating spacer.) The insulating support forming the insulating spacer generally uses aluminum oxide (hereinafter, referred to as alumina) as a filler. It is a molded product cast with an epoxy resin and has a dielectric constant of about 6.0. On the other hand, SF6 gas generally used for gas insulation equipment is decomposed by high energy due to arc or corona discharge generated at the time of interruption,
Further, it reacts with moisture in the air and the insulator to generate hydrofluoric acid. Silica powder, which is generally used as an insulating material of an insulating support, has a low dielectric constant (ε = 4.5) but is easily corroded by hydrofluoric acid. In contrast, alumina powder has a high dielectric constant (ε = 9.3), but has low chemical reactivity with hydrofluoric acid and is hardly corroded. That is, silica powder cannot be used as a filler, and alumina powder is used as a filler. The dielectric constant of an insulating support cast with an epoxy resin using silica powder as a filler is 3.6 to 3.8, whereas the dielectric support is cast with an epoxy resin using alumina powder as a filler. The dielectric constant of the insulating support is about 6.0. On the other hand, the dielectric constant of the insulating gas is about 1, which is a fraction of the dielectric constant of the insulating support. Here, FIG. 4 shows a group 8 of equipotential lines when an epoxy mold material filled with alumina powder is used as a constituent material of the insulating support 4. (The conductor connection electrode constituting the insulating spacer is not shown.) Conductor 2
The end of the junction between the substrate and the insulating support 4 is called a triple junction 5 and is an interface between three substances, namely, the conductor 2, the insulating support 4 and the insulating gas (not shown). Due to the difference, the electric field is concentrated at the acute angle portion, and as shown in FIG. 4, the bending of the equipotential line 8 at the triple junction 5 becomes considerably large. That is, the change in the electric field strength per unit distance locally increases, and the withstand voltage decreases significantly. This example is a case where the insulating support 4 is formed in a conical shape and the corners of the joints are acute. However, in other shapes of the insulating support 4 where there is no acute angle, In the triple junction 5 part, a minute gap is apt to be generated due to a processing error or a difference in material properties, etc., and an electric field is concentrated in the gap due to a difference in dielectric constant between the insulating support 4 and the insulating gas. descend.

In order to prevent such a phenomenon, it has been conventionally considered to reduce the concentration of the electric field by lowering the dielectric constant of the insulating material forming the insulating support. The voltage applied to the device is distributed to each insulator at a voltage proportional to the reciprocal of the dielectric constant. In other words, a high voltage is shared between insulators having a low relative dielectric constant, but if the difference between the dielectric constants of two adjacent substances is large, the difference between the shared voltages is also large. Therefore, when there is an acute angle portion, a minute gap, or the like at the interface between two adjacent substances, the electric field is likely to be concentrated at that portion. In an actual device, a high electric field is concentrated on a triple junction or the like as described above. Therefore, if the dielectric constant of the insulating material forming the insulating support can be reduced to reduce the difference from the dielectric constant (ε = 1) of the insulating gas, the concentration of the electric field is reduced.
For example, in Japanese Patent Laid-Open No. 4-130126, alumina and dolomite (magnesium calcium carbonate) are used as fillers.
The use of a mixed system of low dielectric constant is attempted, and in Japanese Patent Application Laid-Open No. H7-15843, a foamed insulator containing an insulating gas as bubbles is used, and in Japanese Patent Application Laid-Open No. 5-198208, a hollow filler is used. The use of an insulator is intended to lower the apparent effective permittivity. FIG. 5 shows a case where the insulating support 4 made of an insulating material whose dielectric constant is lowered to about 4.0 is applied to the above example. By comparing FIG. 4 with FIG. 5, it can be seen that the bending of the equipotential line group 8 is considerably reduced in FIG.

[0004]

As described above, it is possible to alleviate the electric field concentration to some extent by lowering the relative permittivity of the insulating support. When creating low dielectric constant insulators,
The following problems arise. First, in the method of changing the type of filler to lower the dielectric constant, as described above, SF
6 To improve the durability against decomposition gas, use alumina powder or dolomite, aluminum fluoride, etc., which have low chemical reactivity with SF6 decomposition gas, instead of silica powder, which has high chemical reactivity with SF6 decomposition gas. Must be used,
In each mixed system of alumina, dolomite, aluminum fluoride, and the like, there is a trade-off between the dielectric constant and the mechanical properties of the produced resin, and it is necessary to consider this point. That is, since alumina has a high relative dielectric constant (ε = 9.3), if dolomite (ε = 8.1), aluminum fluoride (ε = 5.0) or the like having a low relative dielectric constant is mixed, the coefficient of linear expansion is large. Therefore, mechanical properties such as bending strength and crack resistance are reduced. Therefore, attempts have been made to optimize the mixing ratio of the filler and the content of the filler from the viewpoint of the balance between the linear expansion coefficient and the relative dielectric constant and the workability, but the internal dielectric strength, heat cycle resistance, and SF6 resistance have been attempted. At present, it has not yet been possible to completely satisfy various characteristics required for gas-insulated equipment, such as decomposition gas properties and mechanical strength.

[0005] Next, in the method of forming a foamed insulator containing bubbles as an insulating gas, in order to produce such a foamed insulator, a method of solidifying a liquid plastic while stirring it in a gas of the insulating gas is used. However, it is extremely difficult to control the size and the position of the bubbles, and it is difficult to actually produce them except in the case where the shape of the insulating support is very simple and the insulating class is low. In the method of using a hollow insulator as a filler, for example, a non-shrinkable minute hollow insulator in an epoxy resin, that is, a hollow hollow insulator such as glass, silica, ceramic, etc. Although a method of dispersing and mixing as a filler is used, cracks tend to occur starting from the boundary layer between the resin and the hollow insulator, and the crack resistance of the product is reduced.

According to the present invention, in the insulating spacer as described above, by providing a high dielectric member inside an insulating support made of an insulating member, the concentration of an electric field is reduced, and the electric field strength at a triple junction is reduced. The purpose is to obtain an insulating spacer.

[0007]

According to the present invention, there is provided an insulating member which is housed in a grounded metal container filled with an insulating gas and has a conductor connecting electrode to which a high voltage is applied and an insulating support for supporting the conductor connecting electrode. In the spacer, an insulating member constituting a main body of the insulating support, and a high dielectric member having a higher dielectric constant than the insulating member provided by being wound on the circumference of the conductor connection electrode in the insulating member. It is characterized by having. Also, a method of manufacturing an insulating spacer is to form a high dielectric member by wrapping a resin impregnated tape having a higher dielectric constant than the insulating member on the circumference of the conductor connection electrode around the circumference of the conductor connection electrode. It is obtained by positioning and disposing in a mold for molding a spacer, and vacuum-casting a high dielectric member using an insulating member. ADVANTAGE OF THE INVENTION According to this invention, in the place where an electric field tends to concentrate, such as a triple junction, bending of the equipotential line due to a difference in dielectric constant can be reduced, and as a result, the concentration of the electric field can be reduced.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, a conductor 9 to which a high voltage is applied is supported by an insulating support 10 via a conductor connection electrode 3 in a hermetically sealed grounded metal container 1 in which an insulating gas is sealed. Conventionally, insulating support 4 of insulating spacer
Is formed in a conical shape as shown in FIG.
When the insulating support 4 is formed in such a shape, the angle of the junction between the insulating support 4 and the conductor 2 at the triple junction 5 becomes acute, and as described above, the two substances having a large difference between adjacent dielectric constants are formed. An acute angle portion exists at the interface, and electric field concentration tends to occur. Therefore, the insulating spacer of the present invention includes an insulating support member 10 having an insulating member 7 constituting a main body, a high dielectric member 6 having a higher dielectric constant than the insulating member 7, and the conductor connection electrode 3. The high dielectric member 6 is formed by winding a resin impregnated tape having a higher dielectric constant than the insulating member 7 around the circumference of the conductor connection electrode 3.

Here, the materials of the insulating member 7 and the high dielectric member 6 will be described. Low dielectric constant resin 16 of insulating member 7
For example, an epoxy resin or the like using a mixed system of alumina and dolomite may be used as a filler having a relative dielectric constant ε of about 5.0, and an internal dielectric strength, heat cycle resistance,
It is possible to mix without sacrificing various characteristics required for gas insulation equipment, such as SF6 decomposition gas resistance and mechanical strength. For the high dielectric member 6 having a higher dielectric constant than the insulating member 7, for example, a resin impregnated tape 18 obtained by impregnating a resin 16 such as epoxy or unsaturated polyester into a reinforcing fiber 17 such as glass, carbon, or aramid is used. Good to use.

The shape of the present embodiment was examined by simulation. As a result, a high dielectric member 6 (having a relative dielectric constant of about ε = 9) having a height and a width approximately half that of the insulating support 4 is provided in a conical shape, and the relative dielectric constant of the insulating member 7 is set to ε = 5. It has been found that the electric field can be most effectively reduced by setting the value to about 0. FIG. 2 shows a simulation diagram of the electric field distribution. As is clear from FIG. 2, since a low dielectric member is sequentially arranged on the low voltage side from the side close to the high voltage conductor 2 to provide a gradient of the dielectric constant, the difference in the voltage shared by each part is reduced. As a result, the concentration of the electric field at the boundary is reduced, and the electric field intensity at the triple junction 5 is reduced.

Next, a method for manufacturing the insulating spacer of the present invention will be described. As defined first, the insulating spacer 20 is constituted by the conductor connection electrode 3 and the insulating support 4. First, as shown in FIG. 6, the conductor connection electrode 3 is attached to the rotating jig 11, the resin 16 is impregnated in the reinforcing fiber 17, and the impregnated resin impregnated tape 18 is wound around the conductor connection electrode 3 to thereby obtain a high dielectric constant member. 6 is formed. Specifically, a reinforcing fiber 17 such as glass, carbon, or aramid is immersed in a resin 16 such as an epoxy resin or an unsaturated polyester resin, and then the rotating jig 11 is rotated at a rotation speed of about 1 to 10 rpm to impregnate the resin. The tape 18 is wound around the conductor connection electrode 3. At this time, in order to make the relative dielectric constant of the high dielectric member 6 approximately 9.0, for example, alumina powder (ε = 9.3) having a high relative dielectric constant is contained in the resin 16 as a filler. In this step, as shown in FIG. 7, the high dielectric member 6 is wound around the conductor connection electrode 3 in a conical shape. Next, as shown in FIG. 8, the conductor connection electrode 3 and the high dielectric member 6 are positioned and arranged on the dies 12 and 13, and are vacuum-cast using a resin 16 having a lower dielectric constant than the high dielectric member 6. The structure according to the invention is obtained. Vacuum casting may be a commonly used method. At this time, resin 1 having a low dielectric constant is used.
The epoxy resin 6 may be, for example, an epoxy resin using a mixed system of alumina and dolomite as a filler as described in the related art. At this time, as described above, the relative dielectric constant of the insulating member 7 is set to 4.
It is not necessary to lower the dielectric constant to around 0, and the relative dielectric constant without lowering other characteristics required for gas-insulated equipment 5.
A blend of around 0 is used. At this time, the same kind of resin is used so that separation between the layers of the high dielectric member 6 and the insulating member 7 does not occur. It is necessary to do. FIG. 9 shows a cross section of the product when the mold is separated from the mold mating surfaces 14 of the molds 12 and 13 to the left and right. Finally, the gate 15 at the time of pouring the resin is removed with sandpaper or the like, so that the insulating spacer 20 is obtained.

[0012]

According to the present invention, in an insulating spacer used for a gas-insulated electric device, a high dielectric member is provided inside an insulating support made of a low dielectric constant material, so that concentration of an electric field is reduced and triple junction is achieved. , The size of the device can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing the structure of an embodiment of the present invention.

FIG. 2 is a simulation diagram of an electric field distribution of an insulating spacer of the present invention.

FIG. 3 is a diagram showing an electric field distribution in the insulating spacer of the present invention.

FIG. 4 is a diagram showing an electric field distribution in a conventional insulating spacer.

FIG. 5 is a diagram showing an electric field distribution in a conventional insulating spacer.

FIG. 6 is a view showing a manufacturing method of the present invention.

FIG. 7 is a view showing a manufacturing method of the present invention.

FIG. 8 is a diagram showing a manufacturing method of the present invention.

FIG. 9 is a diagram showing a manufacturing method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ground metal container 2,9 Conductor 3 Conductor connection electrode 4 Insulating support 5 Triple junction 6 High dielectric member 7 Insulating member 8 Equipotential line group 10 Insulating support (insulating member 7 + high dielectric member 6) 11 Rotating jig 12, 13 mold 14 mold mating surface 15 gate 16 resin 17 reinforcing fiber 18 resin impregnated tape 20 insulating spacer

Claims (2)

[Claims] 1. A conductor connecting electrode housed in a grounded metal container filled with an insulating gas and connected to a conductor to which a high voltage is applied, and an insulating support for supporting the conductor via the conductor connecting electrode. Insulating spacer having a body having a higher dielectric constant than the insulating member which is provided on the circumference of the conductor connection electrode in the insulating member and which forms the main body of the insulating support. An insulating spacer comprising a dielectric member. 2. A conductor connecting electrode housed in a grounded metal container filled with an insulating gas and connected to a conductor to which a high voltage is applied, and an insulating support for supporting the conductor via the conductor connecting electrode. In the method for manufacturing an insulating spacer having
The high dielectric member is formed by being wound around the circumference of the conductor connection electrode in the insulating member, and the high dielectric member is positioned and arranged in a mold for molding the insulating spacer, and vacuum-cast with the insulating member. A method for manufacturing an insulating spacer, comprising: