JPH02142010A - Spacer for gas insulating transformer - Google Patents

Abstract

PURPOSE:To make it possible to use an insulation spacer for sulfur hexafluoride gas-insulated transformer and to improve its tensile strength, compressive strength, punching property, and heat resistance by specifying thickness, bulk density, tensile strength, tensile elongation, and dielectric breakdown strength of an insulation spacer composed of an aromatic polyamide pulp, an aromatic polyamide short fiber and/or polyester short fiber. CONSTITUTION:The thickness, bulk density, tensile strength, tensile elongation, and dielectric breakdown strength of an insulation spacer composed of an aromatic polyamide pulp, an aromatic polyamide short fiber, and/or a polyester short fiber are determined to be 0.8-5.0mm, 0.95-1.3g/cm<3>, >=4.0kg/mm<2>, >=5% and <15% and >=1.2KV/mm, respectively. By this, an insulation spacer for a gas insulating transformer with high resistance to sulfur hexafluoride in E or F as well as necessary tensile strength and compressive strength as an insulation spacer and also high heat resistance, punching property, and electric properties is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an insulating spacer used in a gas insulation degree IE device for gas insulation such as hexanovated sulfur gas. More specifically, tensile strength, compressive strength, and batting properties.

This relates to a spacer for gas insulated transformers that has excellent heat resistance.

[Prior art] The transformer uses cold u1 to increase insulation strength and cold fJI efficiency.
A Urahito transformer, in which the medium, insulating oil, is housed in a container is commonly used. When using a transformer indoors, mineral oil is a flammable oil, so from the standpoint of disaster prevention, a non-flammable transformer that does not use mineral oil is required, and dry type transformers or non-flammable oil transformers have been used. The use of polychlorinated biphenyls as non-combustible oil was banned in 1999, and thereafter, l'' dry-type transformers were mainly used as non-combustible transformers, and molded transformers also came into use. 1-1 dry transformer and molded transformer are used as non-combustible transformers, but the main insulation depends on the dielectric strength of the air, so the voltage is limited to 3OKV class and 10MVA class for guest rooms. It is believed that. For this reason, electrical t1 gases such as sulfur hexafluoride gas have come to be used as an insulating medium for nonflammable transformers of 66 V class or higher, or IOM VΔ class or higher.

In addition, an oil-immersed transformer that uses expensive silicone oil instead of polychlorinated biphenyl as a non-combustible oil is also available! X
used for various purposes.

As insulating spacers used in oil-immersed transformers, breathpods made of high-quality vegetable fibers such as cotton fibers and Kura 71-bulb are used. On the other hand, a spacer made of an aromatic polymer and an inorganic fiber (Japanese Unexamined Patent Publication No. 54-41500q) or a spacer made of an aromatic polyamide fibrid and a high temperature resistant block (Japanese Unexamined Patent Publication No. 1982-41500q) using a modified If device is used. Kaisho [30-209100 Publication] etc. are used.

Cellulose based insulators for gas insulated transformers do not use insulating oil, which is a cold 7JI medium, resulting in poor heat dissipation and insufficient heat resistance.On the other hand, polyimide or y'i-a M polyamide Although it has sufficient heat resistance, it has the disadvantages of being of excessive quality and being expensive.

The manufacturing method for boards used for insulating spacers is generally to form wet paper by wet papermaking, and after laminating any number of sheets of wet paper whose moisture content is adjusted to 50 to 95%, For example, a method of dehydrating and drying under heat and pressure using a board machine manufactured by Weidmann of Switzerland is used, as described in Japanese Patent Application Laid-Open No. 54-41500, and the above-mentioned Special Publication No. 111 (io-1). This is the first-stage manufacturing method described in the publication No. 209100.

For heat-insulating, sound-insulating, and non-combustible boards that are mainly composed of mineral fibers, there is a method of hot-pressing powdered resin onto a mat-like string (Japanese Patent Application Laid-open No. 130802J-J).

Polyester plastic film (') is known as an E-class insulating material. ni J'l' lgana number)
However, anything other than a paper layer structure has poor compatibility and cannot be used for practical purposes.

As a known technology that is used for 13 or more types of electrical insulating materials, it is treated as a laminated layer for printed circuits - C Special Publication 1g (!1227
No. 189, Metal clad insulating sheet No. 14 Publication No. 56-1792, Heat-resistant paper No. 60126
Publication No. 400 is known and J3 is all made of aromatic polyamide! It is a mixture of 31 and polyester fibers. Also, a mixture of aromatic polyamide fibrids and polyester fibers is known as a synthetic paper (Japanese Patent Application Laid-Open No. 1983-1999-
231302).

[Objective of the Invention] 1.1 The purpose of the present invention is to improve the heat resistance of cellulose-based breathpods, which have the disadvantages of conventional insulating spacers, and to improve the heat resistance of cellulose-based breathpods, which have the drawbacks of conventional insulating spacers. 67) Practical insulation for gas insulated transformers that is resistant to sulfur gas, has sufficient tensile and compressive strength required for insulating substrates, has good striking properties, and has excellent electrical properties. Intended to provide spacers.

[Structure of the Invention] The present invention provides an insulating spacer made of aromatic polyamide pulp, aromatic polyamide staple fibers and/or polyvarnish-1 fibers, having a thickness of 0.8 to 5.0 M and a bulk density of 0.95-1.37/cd, bow length strength 4.0
kg/mm2 or more, tensile elongation less than 15% or more than 5%"-1
A spacer for gas insulated transformers whose special feature is a dielectric breakdown strength of 1.2 KV/am or more.

The aromatic polyamide used in Book 5F, Akira, is a dicarboxylic acid having a conventionally known (a) aromatic ring. Synthetic polyamide formation with a diamine having a 5M ring) Condensed polyamide (C) formed by condensing an aminocarboxylic acid having a hexaaromatic ring (C) A polyamide obtained by copolymerizing the above (a)).

Aromatic polyamide valves are known, for example, 1Si Kosho 3s.
-11851 and Japanese Patent Publication No. 37-5732. In particular, poly(IIl-)J, nylene isophthalamide) is preferred.

The aromatic polyamide short fibers are also preferably poly(m-71 nylene isophthalamide). As for the form of short m fibers, those having a single fiber fineness of 20 deniers or less and an Ili coarse length of 3 to 20 M are preferable.

The polyester fiber is a 16 polyester in which a dibasic acid component is a known aliphatic dicarboxylic acid, an aliphatic alicyclic or aromatic glycol, or a poly'A1 dialkylene glycol such as polyethylene glycol as a glycol component. A copolymerized polyester containing one type or a combination of two or more of these dibasic acid components or glycol components (may also be used).

A particularly preferred example is polyethylene terephthalate. C may also be used, using ordinary fiber additives.

The present polyester ml1t is preferably short fibers with a medium fineness of 20 deniers or less and a fiber size of 3 to 20 am, but it is also possible to use short fibers with a fiber size of 3 to 20 am. It may be composed of both.

Further, as the drawn yarn, flat yarn having an aspect ratio of 2.5 or more is preferable. In the present invention, the aspect ratio refers to the thickest cross-sectional length (1
-IIlax) (Lmax/Wmax). When the aspect ratio is less than 2.5, the density improvement of the hot-pressed 'Jl pattern is insufficient. Various known cross-sectional shapes of the flat yarn can be used. The polyester fiber of the present invention is preferably a combination of a drawn yarn with an aspect ratio of 2.5 or more and an undrawn yarn. Mechanical properties of the board in this case,
It has particularly good electrical properties.

If the bulb content is less than 10%, the electrical properties, especially the dielectric breakdown strength, will be low, and if it exceeds 90%, the mechanical properties such as compressive strength will deteriorate. Insulating spacer - Minimum 0.8 when used in a doji. A board with a thickness exceeding 5.0M is required, and a board of uniform quality cannot be obtained because the heat transfer when covered with a hot-sealing press is poor. Bulk density to 0.95-
It is in the range of 1.3 y/cm.

If it is less than 0.95'J/cIli, the mechanical properties such as tensile strength and compressive strength IC1 will deteriorate and it will not be possible to support the large compressive force applied to the insulating spacer in the event of a short-circuit accident in the transformer. Also, peeling between the paper layers laminated on the spacer is likely to occur. -'fj L3' When J/ci is exceeded, the board becomes plastic-like and cracks occur in the spacer after one hit, making it impossible to handle.

The range of tensile strength is 4.0 KrJln- or more.

Tensile strength 4. OX! ? If the mechanical properties are less than /-, the performance as a board will be poor, and as mentioned above, it will be difficult to withstand when a large force is applied to the insulating spacer due to a 5.111M failure in a transformer.

The tensile elongation is required to be less than 15% and 5% or more for the same reason as the tensile strength. The dielectric breakdown strength must be 12KV/M or higher. If it is less than 12KV/volt, it is not suitable for insulation of transformers to which high voltage is applied.

[Effects of the Invention] The insulating spacer obtained according to the present invention has the following effects. In other words, the conventional cell 1゛ course type breathboard has poor heat resistance and cannot be used for 6F A gas insulation transformers, but the insulating spacer according to the present invention has low heat resistance.
It can be used for insulating transformers of six or more types.

[Example] Hereinafter, the method for manufacturing a spacer for a gas insulated transformer of the present invention will be explained in Examples.

Each measurement value in J3 in the example was determined by the following method: 1. P. What did you do?

(1) Tsubo hanging: According to JIS P8124 U 1llll + 1° (2) Thickness Al according to JIS C21115, 2 using 2 micrometers
established.

(3) Density: 3 (11) according to JTS C2111 6.1.

(4) Water ratio: Measured at 8 of C2+11.

(5) Tensile strength and elongation: Measured according to JIS C2111 7 using a constant speed Yoshiyoshi JKlj tensile tester.

(6) Compressive strength and shrinkage: constant speed L [shrinkage! Using a J2 f [shrinkage tester], rimples with an area of 205 x 20 mm were stacked on 19 of about 25M and measured at a speed of 1/10.

(7) Dielectric breakdown strength (BD): JIS C211
+18.1 d country is established.

(8) Surface and volume resistivity: JIS KG91
15, 13.

(9) Dielectric f2: JIS KI39115
．． 14.

CK) 1 Punching property: Using a blade die with a click force press c
Batting style was evaluated.

U Long-term heat resistance: C was measured according to the test method of UL7463.

Examples 1-2. Comparative Example 1 Polymetaphenylene isophthalamide was produced by the interfacial polymerization method described in Japanese Patent Publication No. 47-108G3.

This polymer has an intrinsic viscosity (+, V,) of 1.35 as measured by dissolving it in N-methyl-2-pyrrolidone, and does not contain any R-free salt in the polymer. This polymer was dissolved in N-medyrupyrrolidone to a polymer concentration of 12.5% by weight to obtain a polymer solution for precipitation. Aqueous solution was prepared by adding water to 10,000N-Mebru 2-bilidone at a concentration of 3Offl% and used as a precipitant. Using this polymer solution and precipitant, JP-A-52-1! +1f3
A valve was manufactured by the method described in the publication using the precipitation apparatus described in the publication No. 2. Using this bulb, a pulper, a rapid disintegrator, and a disc refiner, an aqueous slurry having a slurry concentration of 0.3% and a Canadian standard freeness of 110 d was prepared. On the other hand, polymetaphenylene isophthalamide drawn yarn 'C single yarn 11 degrees 2.0 denier fiber length G
, 0#I short fiber and/or polyester drawn yarn, single yarn fineness 2.5 denier, fiber H length s, onn flatness 4
．． 0 polyethylene terephthalate fiber and single yarn fineness 1
．． The above valve slurry and polymetaphenylene isophthalamides were obtained by dissolving and dispersing undrawn polyethylene terephthalate 1-short IIM yarn with a circular cross section of 1 denier and m fiber length of 5.0 M using a pulper at a concentration of 1%. ! &ItIi
and/or polyethylene alephthalate short fiber dispersion slurry to make a uniform paper slurry. Next, use a fourdrinier paper machine at a paper making speed of 20 m/1n. b iA7 >
:T--Door IXy-F After drying, it was removed. The obtained dry paper was slit to a size of 1 m width and 2 Tn length using a slitting machine.

Stack 20 sheets of 11-knotted slit paper u240℃r1
A board was prepared by hot pressing with a press for 5 minutes at a surface pressure of 50 to 9/crA.

Table 1 shows the characteristics of the 1ξ1 board. Comparative example 1
The value of Lerulose-based breathpod is shown as ゛.

Table The insulating spacer of the present invention has excellent electrical properties and low moisture content compared to the breath board of Comparative Example 1, and unlike cellulose, it does not absorb water, so it can be easily absorbed by BIIJ and has excellent heat resistance. Therefore, it is useful as an insulation spacer for gas insulated transformers.

Claims (3)

[Claims] (1) An insulating spacer made of aromatic polyamide pulp, aromatic polyamide short fibers and/or polyester short fibers with a thickness of 0.8 mm to 5.0 mm and a bulk density of 0.
．． 95~1.3g/cm^3, tensile strength 4.0kg/
A spacer for a gas insulated transformer, characterized in that it has a tensile elongation of less than 15% and 5% or more, and a dielectric breakdown strength of 12KV/mm or more. (2) The spacer for a gas insulated transformer according to claim (1), wherein the polyester short fibers consist of drawn polyester yarn and undrawn yarn. (3) The spacer for a gas insulated transformer according to claim (1) or (2), wherein the drawn polyester yarn is a flat yarn with an aspect ratio of 2.5 or more.