JPH11224537A - Insulating spacer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insulating spacer excellent in insulating reliability and having a low dielectric constant and satisfactory SF6 decomposition gas resistance by comprising a hardened matter of an epoxy resin composition containing a multifunctional epoxy resin, an acid anhydride hardener, a softener, and aluminum fluoride and alumina having maximum particle sizes of a specified value or less as filler. SOLUTION: This insulating spacer is formed of a hardened matter of epoxy resin composition containing a multifunctional epoxy resin having an epoxy equivalent of 150-250, an acid anhydride hardener, a softener, and alumina fluoride and alumina having maximum particle sizes of 44 μm or less as filler. As the epoxy resin, bisphenol A/F or F-type epoxy resin is desirable. As the acid anhydride hardener, general acid anhydrides such as methylhexahydro phthalic anhydride or the like are usable without limitation. As the filler, a mixture of aluminum fluoride and alumina is used, and the mixing ratio is desirably 9/1-5/5 by weight. This spacer is used as a conical insulating spacer 1 for supporting a conductor 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulating spacer, and more particularly, to an insulating spacer for insulating and supporting a conductor provided in a container filled with an insulating gas.

[0002]

2. Description of the Related Art Conventionally, gas insulated equipment such as a gas insulated switchgear or a gas insulated conduit air transmission line is electrically connected to a sealed container filled with an insulating gas such as SF ₆ gas. An insulating spacer is provided to support the power application unit conductor in an insulated state. As a material of the insulating spacer, a material obtained by blending various fillers with a thermosetting resin such as an epoxy resin is usually employed. As the filler, for example, when a silica (SiO ₂ ) -based material is used, there is a problem that the insulating property is reduced due to the influence of a decomposition gas generated by an arc or the like at the time of interrupting the current. Uses alumina having high SF ₆ decomposition gas resistance.

[0003] In recent years, with the increase in power demand, gas insulated switchgear has been required to be reduced in size and increased in capacity, and insulating spacers have been required to have a low dielectric constant and high heat resistance. Conventionally, the dielectric constant is low, though excellent in resistance to SF ₆ decomposition gas insulating spacer fillers are, for example, JP-57-
As described in JP-A-203508 and JP-A-9-176288, those using a mixed filler of aluminum fluoride and alumina are known.

[0004]

However, the fillers disclosed in the above publications have been shown to use a filler having a specific particle size distribution for the purpose of improving castability and mechanical strength. However, no consideration is given to the insulation reliability, particularly the variation in the internal penetration breakdown electric field value.

SUMMARY OF THE INVENTION An object of the present invention is to provide an insulating spacer which has a small variation in an internal penetration breakdown electric field value, is excellent in insulation reliability, has a low dielectric constant, and has good resistance to SF ₆ decomposition gas.

[0006]

In order to achieve the above object, the present invention employs the following means.

In an insulating spacer for insulating and supporting a conductor disposed in a container filled with an insulating gas, the insulating spacer is used as a polyfunctional epoxy resin, an acid anhydride curing agent, a flexible agent, and a filler. It is characterized by being formed of a cured product of an epoxy resin composition containing aluminum fluoride and alumina having a maximum particle size of 44 μm or less.

In an insulating spacer for insulating and supporting a conductor provided in a container filled with an insulating gas, the insulating spacer comprises a polyfunctional epoxy resin having an epoxy equivalent of 150 to 250, an acid anhydride hardener, The maximum particle size is 44 μm or less, and the average particle size is 1 to 20 μm as a flexible agent and a filler.
m and a cured product of an epoxy resin composition containing aluminum fluoride and alumina.

An SF ₆ gas insulated switchgear provided with a container filled with SF ₆ gas, a conductor disposed in the container, and an insulating spacer for insulating and supporting the conductor.
The insulating spacer is a cured epoxy resin composition containing a polyfunctional epoxy resin having an epoxy equivalent of 150 to 250, an acid anhydride curing agent, a flexibilizing agent, and aluminum fluoride and alumina having a maximum particle size of 44 μm or less as a filler. It is characterized by being formed of an object.

[0010] Also, in the SF ₆ gas insulated conduit air transmission line provided with a container filled with SF ₆ gas, a conductor disposed in the container, and an insulating spacer for insulatingly supporting the conductor, The insulating spacer has an epoxy equivalent of 150 to 25.
It is characterized by being formed of a cured product of an epoxy resin composition containing aluminum fluoride and alumina having a maximum particle size of 44 μm or less as a polyfunctional epoxy resin, an acid anhydride curing agent, a flexibilizing agent, and a filler. And

[0011]

Embodiments of the present invention will be described below.

First, a polyfunctional epoxy resin constituting the insulating spacer of the present invention, an acid anhydride curing agent, a flexible agent,
And each material of the filler will be described.

The epoxy resin used in the present invention is a polyfunctional epoxy resin, preferably having an epoxy equivalent of 1 because of its high heat resistance and low viscosity and good workability.
Employ 50 to 250 polyfunctional epoxy resins. As the polyfunctional epoxy resin having an epoxy equivalent of 150 to 250, bisphenol A / F type or bisphenol F type epoxy resin is preferable because of its excellent heat resistance. Although the glass transition temperature of the cured product of the present invention depends on the combination with the acid anhydride curing agent, it is higher than that having an epoxy equivalent of more than 250, and is preferably 130 ° C. or more. In addition,
In addition, a bifunctional epoxy resin such as a bisphenol A type epoxy resin and a bisphenol AD type epoxy resin, a phenol novolak type epoxy resin, a bisphenol A novolak type epoxy resin, and an alicyclic epoxy resin can also be used. These may be used in combination.

The acid anhydride curing agent used in the present invention includes:
There is no particular limitation as long as it is a general acid anhydride. Such acid anhydrides include methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, tetrahydrophthalic anhydride, nadic anhydride,
There are methylnadic anhydride, dodecylsuccinic anhydride, succinic anhydride, octadecylsuccinic anhydride, maleic anhydride, benzophenonetetracarboxylic anhydride, and the like, or a mixture thereof.

In the present invention, the epoxy equivalent is 150 to 250.
The use of a polyfunctional epoxy resin requires the addition of a flexible agent. As the solubilizing agent to be used, those which are incompatible with the epoxy resin and have a sea-island structure are preferable since the decrease in the glass transition temperature of the cured product is small and the crack resistance can be improved. As such a solubilizing agent, for example, a carboxyl group-terminated butadiene-
Acrylonitrile rubber, amine-terminated butadiene-acrylonitrile rubber, acrylic rubber, styrene-butadiene rubber, acrylonitrile-butadiene-styrene resin,
Methyl methacrylate-butadiene-styrene resin and the like. These flexible agents may be used in any of a monostructure structure and a core-shell structure. The amount of the flexibilizing agent is 40% by weight or less, more preferably 3 to 30% by weight, based on the epoxy resin and the acid anhydride used. When the amount is large, the glass transition temperature is lowered, and when the amount is small, crack resistance is deteriorated.

The filler used in the present invention comprises a mixture of aluminum fluoride and alumina. The mixing ratio is preferably from 9/1 to 5/5, more preferably 8/2, of aluminum fluoride / alumina. ６6/4. When the amount of aluminum fluoride increases, the mechanical strength decreases, and when the amount is low, the relative dielectric constant increases. The filler is added so that the value of the relative dielectric constant becomes lower than the value of the alumina alone filling (5.5 to 6.5), and the value of the relative dielectric constant of the resin alone becomes from 3.5. 5.
It is preferable to adjust so as to fall within the range of 4. The maximum particle size and the average particle size of the filler can be determined by, for example, a laser diffraction particle size distribution analyzer, Nikkiso Microtrac-FRA.

In the present invention, other fillers may be used together if the maximum particle size is 44 μm or less. Examples of such a filler include magnesium oxide, calcium carbonate, magnesium carbonate, dolomite, calcium hydroxide, magnesium hydroxide, calcium sulfate, barium sulfate, calcium fluoride, magnesium fluoride and the like. The filler may be used in a crushed or spherical shape alone or in a mixture.

In the present invention, a curing accelerator may be added as required. The curing accelerator is not particularly limited as long as it has a function of curing the polyfunctional epoxy resin.

Further, a coloring agent, an antioxidant, a coupling agent and the like may be added as required.

According to the present invention, a conductor provided in a container filled with an insulating gas, using the above-described materials of the polyfunctional epoxy resin, the acid anhydride curing agent, the plasticizing agent, and the filler. As an insulating spacer that insulates and supports the epoxy resin composition, a polyfunctional epoxy resin, an acid anhydride curing agent, a flexibilizing agent, and a filler having a maximum particle diameter of 44 μm or less, comprising an epoxy resin composition containing aluminum fluoride and alumina. Form.

Further, as the insulating spacer, a polyfunctional epoxy resin having an epoxy equivalent of 150 to 250, an acid anhydride curing agent, a flexible agent and a filler having a maximum particle size of 44 μm or less and an average particle size of 1 to 20 μm. It is formed of a cured product made of an epoxy resin composition containing aluminum fluoride and alumina.

According to the present invention, by forming the insulating spacer according to the above-mentioned requirements, the variation in the internal penetration breakdown electric field value can be greatly reduced. It is considered that the reason is as follows.

Usually, the cause of the variation in the internal penetration breakdown electric field value is adhesion between the resin and the filler. Regarding the adhesiveness between the resin and the filler, the larger the particle size of the filler, the more the portion where the adhesiveness between the resin and the filler is poor. From this, it is considered that a filler having a larger particle size has a higher probability of dielectric breakdown. In addition, the larger the particle size of the amorphous filler, the larger the portion where electric field concentration is likely to occur, and the higher the probability of dielectric breakdown. Furthermore, since the possibility that the filler having a large particle size exists near the electrode surface is increased, it is considered that the probability of dielectric breakdown is further increased.

Therefore, by using a filler having a small particle size as in the present invention, the probability of dielectric breakdown at a low electric field is reduced, and variations in the internal penetration breakdown electric field value can be reduced. When the maximum particle size is smaller than about 70 μm, a tendency of reducing the variation appears, but when the maximum particle size is smaller than 45 μm, the reduction of the variation becomes remarkable.

In the present invention, the workability is good because the filler is unlikely to settle, and the mechanical strength is also good.

Next, Examples 1 to 3 of the present invention and Comparative Examples 1 to 4 for comparison with the Examples will be described.

Table 1 shows the particle size of AlF ₃ used in the filler of each of the above Examples and Comparative Examples and the test results of each of the above Examples and Comparative Examples. Table 1
Numerals 1 to 5 shown in the internal penetration breakdown electric field value indicate the number of times of the internal penetration breakdown test.

FIG. 1 is a graph showing the test results shown in Table 1.

FIG. 2 is a sectional view of a main part showing a part of a gas-insulated device such as a gas-insulated conduit air transmission line using the insulating spacer according to the present invention. 2 is a post type insulating spacer, 3 is a high voltage conductor,
4 is a closed container, 5 is a conductor, and 6 is an embedding metal fitting.

Example 1 As a polyfunctional epoxy resin, 100 parts by weight of a bisphenol A / F type epoxy resin (epoxy equivalent: 175), 95 parts by weight of methylhexahydrophthalic anhydride (acid anhydride equivalent: 168), and a curing accelerator 0.3 parts by weight of 1- (2-cyanoethyl) -2-ethyl-4-methylimidazole, 25 parts by weight of a methyl methacrylate-butadiene-styrene resin as a solubilizer, and 330 as a filler
Sifting with a mesh (45 μm) sieve, 437 parts by weight of AlF ₃ having a maximum particle size of 45 μm and an average particle size of 17.5 μm as shown in Table 1, and a maximum particle size of 37 μm;
218 parts by weight of Al ₂ O _{3 having} an average particle size of 3.9 μm were mixed and mixed.
The mixture was stirred under vacuum at 0 ° C. to obtain an epoxy resin composition for an insulating spacer. This is poured into a mold, and 90 ° C./17 hours + 15
Heating and curing at 0 ° C./20 hours yielded a conical insulating spacer 1 (720 mm in diameter) shown in FIG. The measurement of the internal penetration breakdown electric field value of the insulating spacer was performed by preparing a cured product with an electrode spacing of 5 mm and performing a step-up method in SF ₆ gas (0.4 MPa). The internal penetration breakdown electric field value of the insulating spacer of this example was 58 to 62 kV / mm, the dispersion was small, and in each case, it was 50 KV / mm or more, and good results were obtained.

Example 2 As a filler, the mixture was sieved with a 391 mesh (38 μm) sieve, and as shown in Table 1, AlF ₃ having a maximum particle size of 38 μm, an average particle size of 15.2 μm, and a maximum particle size of 37 μm.
m, Al ₂ O ₃ having an average particle size of 3.9 μm was used. Otherwise, the insulating spacer 1 was manufactured in the same manner as in Example 1, and the internal penetration breakdown electric field value was measured. As a result, as shown in Table 1 and FIG. 1, the internal through-breakdown electric field value of the insulating spacer of this example was 62 kV / mm, and good results were obtained without any variation.

Example 3 As a filler, as shown in Table 1, AlF ₃ having a maximum particle size of 22 μm and an average particle size of 7.6 μm (not sieved), and a maximum particle size of 37 μm and an average particle size of 3 were used. .9μ
m, the Al ₂ 0 ₃ of using. Otherwise, the insulating spacer 1 was manufactured in the same manner as in Example 1, and the internal penetration breakdown electric field value was measured. As a result, as shown in Table 1 and FIG.
It was 2 kV / mm, and good results were obtained with little variation.

Comparative Example 1 A 140 mesh (106 μm) sieve was used as a filler, and the maximum particle size was 106 μm as shown in Table 1.
m, AlF ₃ having an average particle size of 17.1 μm, and Al ₂ O ₃ having a maximum particle size of 37 μm and an average particle size of 3.9 μm were used. Otherwise, the insulating spacer 1 was manufactured in the same manner as in Example 1, and the internal penetration breakdown electric field value was measured. As shown in Table 1 and FIG. 1, the internal penetration breakdown electric field value of the insulating spacer of this comparative example was 42 to 62 kV / mm, and the dispersion was large.

Comparative Example 2 As a filler, the mixture was sieved with a 200 mesh (75 μm) sieve, and as shown in Table 1, AlF ₃ having a maximum particle size of 75 μm, an average particle size of 16.5 μm, and a maximum particle size of 37 μm.
m, Al ₂ O ₃ having an average particle size of 3.9 μm was used. Otherwise, the insulating spacer 1 was manufactured in the same manner as in Example 1, and the internal penetration breakdown electric field value was measured. The internal penetration breakdown electric field value of the insulating spacer of this comparative example is, as shown in Table 1 and FIG.
42 to 62 kV / mm, and the variation was large.

Comparative Example 3 As a filler, the mixture was sieved with a 100-mesh (150 μm) sieve, and as shown in Table 1, the maximum particle size was 150 μm.
m, AlF ₃ having an average particle size of 31.5 μm, and Al ₂ O ₃ having a maximum particle size of 37 μm and an average particle size of 3.9 μm were used. Otherwise, the insulating spacer 1 was manufactured in the same manner as in Example 1, and the internal penetration breakdown electric field value was measured. As shown in Table 1 and FIG. 1, the internal penetration breakdown electric field value of the insulating spacer of this comparative example was 42 to 56 kV / mm, and the dispersion was large.

Comparative Example 4 As a filler, as shown in Table 1, AlF ₃ having a maximum particle size of 50 μm and an average particle size of 10.3 μm (not sieved), and a maximum particle size of 37 μm and an average particle size 3.9 μm Al ₂ O ₃ was used. Otherwise, the insulating spacer 1 was manufactured in the same manner as in Example 1, and the internal penetration breakdown electric field value was measured. As shown in Table 1 and FIG. 1, the internal penetration breakdown electric field value of the insulating spacer of this comparative example is 44 to 62 k.
V / mm, and the variation was large.

[0037]

[Table 1]

As described above, as can be seen from the test results shown in Table 1 and FIG. 1, the internal penetration breakdown electric field values of the insulating spacers of Examples 1 to 3 are all 50 kV / mm or more, and are good with little variation. Results were obtained. On the other hand, the electric field value of the internal penetration breakdown of the insulating spacers of Comparative Examples 1 to 4 was 4
It is clear that the insulation reliability is as low as 2 kV / mm, and the variation is large, and the insulation reliability is inferior to those of Examples 1 to 3.

The bending strength and relative permittivity of the insulating spacers obtained in Examples 1 to 3 and Comparative Examples 1 to 4 were measured as follows.
The measurement was performed according to JIS K6911. From the test results, it was found that the insulating spacers of Examples 1 to 3 had good bending strength and low dielectric constant.

Examples 1 to 3 and Comparative Examples 1 to 4
Was measured in accordance with JIS K6911 and found to be 130 ° C. or higher in all cases and good heat resistance.

FIG. 3 is a schematic cross-sectional view showing an example of an SF ₆ gas insulated switchgear incorporating the insulating spacer 1 of the first embodiment, and includes a bushing 7, a disconnector 8, and a circuit breaker 9.
By incorporating the insulating spacer 1 of Example 1 as the insulating spacer 1 of the F ₆ gas insulated switchgear, insulation reliability could be improved. Also, by using this insulating spacer 1, the sealed container diameter of the gas insulated switchgear can be reduced by 12%.
Could be reduced.

[0042]

As described above, according to the present invention, the variation of the internal penetration breakdown electric field value is small, the insulation reliability is excellent,
In addition, an insulating spacer having a low dielectric constant and good SF ₆ decomposition gas resistance can be obtained. Further, by using the insulating spacer of the present invention, the SF ₆ gas insulated switchgear and the SF ₆
High reliability of the gas-insulated pipeline air transmission line can be realized.

[Brief description of the drawings]

FIG. 1 shows Examples 1 to 3 and Comparative Example 1 according to the present invention.
9 is a graph showing results of an internal penetration fracture test of Comparative Example 4 in a graph.

FIG. 2 is a sectional view of a main part of a gas insulated switchgear using an insulating spacer and a gas insulated conduit air transmission line according to the present invention.

FIG. 3 is a schematic sectional view showing a configuration of an SF ₆ gas insulated switchgear of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 cone-shaped insulating spacer 2 post-shaped insulating spacer 3 high-voltage conductor 4 closed vessel 5 conductor 6 embedded metal fitting 7 bushing 8 disconnector 9 circuit breaker

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Hiroshi Ozawa 1-1-1, Kokubuncho, Hitachi City, Ibaraki Prefecture Inside the Hitachi, Ltd. Kokubu Plant

Claims (4)

[Claims] 1. An insulating spacer for insulating and supporting a conductor disposed in a container filled with an insulating gas, the insulating spacer comprising a polyfunctional epoxy resin, an acid anhydride hardener, a flexible agent, and a filler. An insulating spacer formed of a cured product of an epoxy resin composition containing aluminum fluoride and alumina having a maximum particle size of 44 μm or less as an agent. 2. An insulating spacer for insulating and supporting a conductor disposed in a container filled with an insulating gas, the insulating spacer comprising a polyfunctional epoxy resin having an epoxy equivalent of 150 to 250, an acid anhydride curing agent, An insulating spacer comprising a cured product of an epoxy resin composition containing aluminum fluoride and alumina having a maximum particle size of 44 μm or less and an average particle size of 1 to 20 μm as a flexible agent and a filler. 3. An SF ₆ gas insulated switchgear provided with a container filled with SF ₆ gas, a conductor disposed in the container, and an insulating spacer for insulating and supporting the conductor, wherein the insulating spacer comprises: Formed from a cured product of an epoxy resin composition containing aluminum fluoride and alumina having a maximum particle diameter of 44 μm or less as a polyfunctional epoxy resin having an epoxy equivalent of 150 to 250, an acid anhydride curing agent, a flexible agent and a filler as a filler. A gas-insulated switchgear. 4. An SF ₆ gas insulated conduit air transmission line comprising a container filled with SF ₆ gas, a conductor disposed in the container, and an insulating spacer for insulating and supporting the conductor. The insulating spacer has an epoxy equivalent of 150 to 250.
Characterized by being formed of a cured product of an epoxy resin composition containing aluminum fluoride and alumina having a maximum particle size of 44 μm or less as a polyfunctional epoxy resin, an acid anhydride curing agent, a flexibilizing agent and a filler. Gas insulated conduit air transmission line.