JPH02142011A - 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>, >=2.5kg/mm<2> and <4.0kg/mm<2>, >=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 field 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 Field of Application) The present invention relates to an insulating spacer used in a gas insulated transformer using 6-sulfur gas. , 111mm fl.

There are some heat-resistant subelements for gas insulated transformers.

[Prior art] Transformer [Cold I for insulation strength and cold 7Jl effect]
Oil-immersed transformers in which insulation i11, which is a JI medium, is housed in a container are 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 a dry type transformer or a non-flammable oil transformer is required. It was Showa 47
The use of polyjn-based bif-L-Nyl, which is contaminated with non-combustible oil by sweat, was banned, and since then it has been used as a non-combustible transformer.
It began to be used in the United States. As a non-combustible transformer - CI-1 dry type transformer, cold type transformer I is used, but the main insulation depends on the dielectric strength of the air (T). is 3
For OKV class, the capacitance is limited to 10 MVA class. For this reason, 66 with V class or higher is 10M VA
Electrically negative gases such as hexafluoride gas have been used as insulating media for non-combustible transformers of grade 1 and above.

Note that H class oil immersion pressurizers, in which expensive silicone oil is used instead of polychlorinated biphenyl as the nonflammable oil, are also used for special purposes.

Insulating spaces used in oil-immersed transformers (J- are made of cotton fibers, kraft bulbs, and other high-quality vegetable fibers. On the other hand, class 1-1 transformers are made of aromatic polymers. and spacers made of inorganic fibers (Japanese Patent Application Laid-open No. 1982-41500), or spacers made of aromatic polyamide fibrids and high temperature resistant blocks (Japanese Patent Application Laid-open No. 60-209100).

As an insulation spacer for gas insulated transformers, cellulose-based breathpods do not use insulating oil as a cooling medium, resulting in poor heat dissipation and insufficient heat resistance.On the other hand, polyimide or IfA polyamide has sufficient heat resistance, but the quality is poor. Excessive and high! 11j There was a drawback that there was a colander.

In general, the manufacturing method for the pods used for insulating substrates is to form wet paper by wet papermaking, and then laminate any number of sheets of wet paper whose moisture content is adjusted to 50 to 95%. For example, Podoma manufactured by Weidmann of Switzerland.
A method of dehydrating and drying under heat and pressure in a thin film is used, and the first step manufacturing method described in JP-A-5441500 and the aforementioned JP-A-209100 is this method. It's a method.

Insulation based on mineral fiber, anti-t1. For non-combustible boards, there is also a method of hot pressing by mixing powdered resin into mat fibers (Japanese Patent Application Laid-Open No. 130802/1982).

Polyester Sderno Ilm and polyester brassnax are known as E type insulation +41-”I, but 0.8
When using a spacer with a thickness of rIa or more as a transformer insulation spacer, it must be stamped into the shape of the spacer, but anything other than a paper layer structure has poor stamping properties and cannot be used in practice.

゛The known technology used as a commercial insulation material for class E and above is the laminate board for printed circuits, etc.
I Publication, Metal Clad Insulating Sheet C Special Publication Sho 56-1
No. 792 and JP-A-60126400 are known as heat-resistant papers, both of which are aromatic polyamide-based m
It is a mixture of H and polyester IMll[. Also known as a synthetic paper is an M1 compound of l'j polyamino neubrid and poly]nystyl short fiber (Japanese Patent Application Laid-Open No. 47-236029, Qfi).

[Object 21] The object of the present invention is to improve the heat resistance of cellulose breath boards, which is a drawback of conventional insulating spacers, and to
E type or 1, which does not require the same quality as S non-group polyamide:
In the field of J3, it is resistant to hexafluoride gas and has sufficient tensile and compressive strength required as an insulating spacer (it is compatible and has excellent electrical properties). Aiming to provide a practical insulator for gas insulated transformers.

[Structure of the Invention] The present invention provides [aromatic polyamide pulp, ``lJ aromatic polyamide short fibers and/'' or polynisdel], υIi?ll
An insulating spacer with a thickness of 0.8 to 5
．． 0M, bulk density 0.95-1.39/crd, tensile strength less than 4.0Ky/-2.5Ki/- or more, tensile elongation 15% or more -L, dielectric breakdown strength 1.2KV/nvn This is a spacer for a gas insulated transformer characterized by the following:

The aromatic polyamide used in the present invention is formed by conventionally known methods (a) condensation polyamidation of a dicarboxylic acid having an aromatic ring and a diamine having an aromatic ring) condensation of an aminocarboxylic acid in which an aromatic ring is n1 Integrated polyamide (C) Examples include polyamide obtained by polymerizing the above (ω-mount) with J (J).

Aromatic polyamide pulp is known, for example, from Japanese Patent Publication No. 3511
This is the book described in Japanese Patent Publication No. 851 and Japanese Patent Publication No. 37-5732. Particularly preferred is poly(l-]1 nylene isophthalamide).

Poly(m-phenylene isophthalamide) is also preferred for the aromatic polyamide fiber. The preferable form of short fibers is one with a single yarn fineness of 20 deniers or less and a fiber length of 3 to 20 M.

The polyester fiber contains two known aliphatic dicarboxylic acids.
A! It is a polyester containing an aliphatic alicyclic or aromatic glycol or a polyonidialkylene glycol such as polyethylene glycol as a component. A copolymerized polyester containing these dibasic acid components or glycol components, respectively, or a combination of two or more thereof may be used.

A preferred example of 1JI is polyethylene phthalate 1-. Ordinary TA navy blue additives may also be used.

The polyester fiber of the present invention preferably has short fibers with a medium fineness of 20 deniers or more and a fiber length of 3 to 20 M, but it may be composed of only drawn yarns and may be composed of both drawn and undrawn yarns. It may be configured b.

Further, as the drawn yarn, flat yarn having an aspect ratio of 2.5 or more is preferable. In the present invention, (l;i A ratio is ()
The largest cross section 1 for the largest width (Wmax)
(LfflaX) ratio (LmaX /WmaX)
It is. If the aspect ratio is less than 2.5, the density improvement after hot press processing 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. The mechanical and electrical properties of the board in this case are particularly good3.

If the pulp content is less than 10%, the electrical properties, particularly the dielectric breakdown strength, will be low, and if it exceeds 90%, the mechanical properties such as compression strength will deteriorate. When used as an insulating spacer, a minimum thickness of 0.8M is required, and boards with a thickness exceeding 5.0M will not be able to produce boards of uniform quality because heat transfer during thermopressure brazing will be poor. Bulk density is 0.95~L
It is in the range of 3g/ctl.

If it is less than 0.959/crt1, the mechanical properties such as tensile strength and compressive strength will deteriorate, and it will not be possible to prevent the excessive compressive force applied to the insulation leveler in the event of a short-circuit accident in the transformer. Moreover, peeling between the paper layers laminated on the spacer occurs due to the poor batting method. - When the pressure exceeds 1,3'J/ctd, the board becomes plastic-like and cannot be punched smoothly (cracks occur when the board bends), making it impossible to punch.

The tensile strength range is 4, OKy/mtA powder K2.
It is more than 1ff/-.

If the mechanical properties are less than 2.5Kg/+- in tensile strength, the f1 performance as a board will be poor, and the short-circuit accident of the transformer as in the previous article 4 will occur.
It cannot withstand when a large force is applied to the c-handle/insulating spacer.

Tensile elongation also requires r15% for the same reason as tensile strength. The dielectric breakdown strength must be 12K V/s or more. If it is less than 12K V/tmn, it is unsuitable as an insulating material for transformers to which high voltage is applied.

[Effects of the Invention] The insulating spacer provided by the present invention has the following effects. In other words, the conventional cell L1-based pressboard has low heat resistance and cannot be used for sulfur hexafluoride gas insulation transformers, but the insulating spacer according to the present invention is of type E or higher and cannot be used for sulfur hexafluoride gas insulation. Can be used in transformers.

[Example 1] Hereinafter, a method for manufacturing a spacer for a gas insulation device according to the present invention will be described in accordance with an example.

Each measurement value a31J in the example is a′P using the following /j method.
This is what I did.

(1) Tsubo fm: JIs []8124kj%LL
;-(Measurement, ri.

(2) Thickness: JISC2 using a micrometer
111 5,2.

(3) Density: Measured according to 6.1 of JIS C2111.

(4) Moisture content: Measured according to JIS C2111-8.

(5) Tensile strength and elongation: Measured according to JIS C21N 7 using a constant speed extension type tensile tester.

(6) Compressive strength and fluffiness: Measured using a constant speed J'' compression tester at a speed of 1 m/min by stacking one number of 20 g x 20 M areas to a thickness of about 25 edges.

(Sword dielectric breakdown strength ([31)V): JIS C21
11, 18.1.

(8) Surface and body 4? I resistance'l: JIS
Measured using KG911 and 13.

(9) Dielectric constant: JIS K09115,14
I'll kill you! It's fixed.

(g)) Punching property: Punching property was evaluated using a cutting die on a Kritsuka press.

Old) Long-term heat resistance: Measured according to the test method of UL 74613.

Go to Example 1・2. Comparative Example 1 Polymetaphenylene isophthalamide was produced manually by interfacial polymerization as described in Japanese Patent Publication No. 1086/1986.

This polymer was dissolved in N-methyl-pyrrolidone and had a hardness and viscosity of 1.3!
l The polymer does not contain any R-free salts. This polymer was converted into N-mediruubi[''ridone at a polymer temperature of 12
．． The polymer solution was dissolved to 5% by weight to obtain a polymer solution for precipitation. On the other hand, add N-Mejiru 2-Bi 1” Ridone to a concentration of 3
J to give 0 weight ω%: Sea urchin was added with water to make an aqueous solution and used as a precipitant. Using this polymer solution and precipitant, JP-A-52
A valve was manufactured by the method described in the publication using the precipitation apparatus N described in the publication. Pulper this valve, high 3! An aqueous slurry with a slurry concentration of 0.3% and a Canadian standard freeness of 110 was prepared using a carp disintegrator and Discrifive. On the other hand, as polymetaphenylene isophthalamide drawn yarn, the single yarn fineness is 2.
O"j' Neil fiber set 6, Om short fiber and/or polynisal drawn yarn, single yarn m degree 2.5 denier, fiber set length b, Olar fli 'l' ratio 4.0 polyethylene deref Talay 1-1.Nm Indo!ljl yarn 1.1f Neal, fiber H length, Onwn circular cross-section poly-1-dylene terephthalate-1 short fiber undrawn yarn 1%
Disintegration and dispersion with Fuchidagu pulper 1! /, :.

The above valve slurry was mixed with poly short fiber nylene isophthalamide fiber and/or poly L (leno)lenotare-1 short fiber dispersion slurry to prepare a homogeneous slurry.

Next, paper was made with a basis weight of 85 l/rrL using a paper making speed of 20111/min using an Ajiro paper machine, dried using a Yankee Dry A7-, and then wound up. 1! 1 m wide x 2 thick dried paper
It was slit using a slitting machine to a size of m.

20 pieces of slit 6 (E, 225℃)
A board was created by hot pressing with a hot press at a surface pressure of 50 m9/ci for 7 minutes.

jtJare1. :The characteristics of the board are shown in Table 1. Comparative Example 1 (Ij
shows.

Table 1 The insulating substrate of the present invention has superior electrical properties and a lower moisture content than the breath pad of Comparative Example 1, and is easy to handle because it does not have adsorbed water like the cell [J-sub]. However, since it has excellent heat resistance, it is useful as an insulating 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 is 4.0kg/m
Less than m^2 2.5kg/mm^2 or more, tensile elongation 15
% or more, and a dielectric breakdown strength of 12 KV/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.