KR102669370B1 - Flange for fastening high voltage bushings for transformers - Google Patents

Abstract

The present invention relates to a high-voltage bushing attached to the top of a transformer, and is composed of a terminal clamp, an insulator, and an integrated flange. The integrated flange has a female-threaded flange fixed to the upper lid by a method such as welding at the bottom of the upper lid of the transformer, and a male-threaded flange. The flange is fastened with a screw method to maintain complete airtightness to prevent contamination of foreign substances and oil leaks. Using a flange tightening jig, the pressure distribution of the fastening area is tightened evenly with a constant torque to prevent eccentricity, making it easy for even unskilled people to use. In addition to making construction possible, coating using a silicon compound material with nano-sized particles is applied to the metal fittings and tightening jigs used in high-pressure bushings to prevent transformer safety accidents due to anti-corrosion and tracking phenomena. It's about.

Description

Flange for fastening high voltage bushings for transformers}

The present invention relates to a high-voltage bushing attached to the top of a transformer, and is composed of a terminal clamp, an insulator, and an integrated flange. The integrated flange has a female-threaded flange on the lower part of the upper lid of the transformer fixed to the upper lid by a method such as welding, and a male-threaded flange. The flange is fastened with a screw method to maintain complete airtightness to prevent contamination of foreign substances and oil leaks. Using a flange tightening jig, the pressure distribution of the fastening area is tightened evenly with a constant torque to prevent eccentricity, making it easy for even unskilled people to use. In addition to making construction possible, coating using a silicon compound material with nano-sized particles is applied to the metal fittings and tightening jigs used in high-pressure bushings to prevent transformer safety accidents due to corrosion resistance and tracking phenomena. It's about.

In general, power supplied at high voltage (22,900V) from a substation is converted to low voltage (220V, 380V) that can be used in general consumers such as homes and industrial sites through a transformer.

At this time, a transformer is a general term for a device that changes alternating voltage and current values through electromagnetic induction. As mentioned above, it converts high-voltage electricity transmitted from the substation through overhead wires into low-voltage electricity required by general consumers and supplies power. A transformer is called a transformer, and a transformer that is usually installed fixed to a utility pole is called a pole-mounted transformer.

The structure of these pole-mounted transformers may differ depending on capacity and voltage, but in common, they essentially include windings and an iron core to perform the function of the transformer, and the windings and iron core are built into a tank filled with insulating oil. The insulating material of the winding prevents moisture or dust from penetrating and deteriorating the dielectric strength, and at the same time dissipates heat generated from the iron core or winding through convection and radiation of oil.

A columnar transformer has a circular enclosure that makes up the body in appearance, an upper lid to seal it, a connecting member that applies high-voltage electricity supplied from the outside to the windings, and a high-voltage bushing installed through the upper lid to redirect the transformed low-voltage electricity. It consists of a low-voltage bushing installed on the outer wall of the enclosure to be taken out to the outside, and a cable to electrically connect the overhead wires outside the columnar transformer and the windings inside the columnar transformer.

At this time, the inside of the enclosure of the columnar transformer is filled with insulating oil to cool the heat generated during transformation.

In addition, the high-pressure bushing not only has sufficient electrical insulation strength, but also has enough support to support the cable connected from the high-voltage overhead wire, and can insulate the high voltage of the connected cable spiral portion, especially salt and dust. To prevent the insulation strength from deteriorating when a light is attached, insulators made of porcelain materials with excellent heat and corrosion resistance are mainly used. However, with the recent development of polymer synthesis technology, high-pressure bushing materials such as EPDM (ethylene propylene rubber), XLPE, Rubber or polymer materials made of polymers such as epoxy and silicone rubber are used.

The high-voltage bushing is installed in the transformer, is electrically connected to the insulator and the transformer, and is fixed to the inside of the insulator. The upper screw shaft is screwed to the connector extending to the top of the insulator and the screw shaft of the connector, and a connection terminal is provided on the top of the insulator. It consists of a terminal clamp in the form of a cap, which is a conductor equipped with a cable to connect it.

Here, the bottom of the insulator is composed of a flange, a spring, and fastening bolts, and the packing at the bottom of the flange is composed between the flange and the upper lid to prevent the insulating oil flowing into the insulator from leaking through the through hole of the upper lid and at the same time to prevent the insulator from leaking through the through hole of the upper lid. It plays a role in preventing damage.

However, the conventional high-pressure bushing moves or applies pressure using a protruding high-pressure bushing during installation or maintenance of a columnar transformer, so that different pressures are transmitted between the three bolts fastened to the flange, causing pressure between the flange and the upper lid. As distortion occurs, oil leakage occurs, or foreign substances such as rainwater enter the transformer and contaminate the insulating oil, which reduces the insulation strength of the transformer and causes frequent accidents such as safety accidents and fires that damage the transformer.

In addition, high-pressure bushings made of brittle materials such as porcelain may be distorted and may cause packing slippage or cracks if the tightening pressure on the three bolts is different during the bolt tightening process. This not only significantly reduces workability, but also causes corrosion of all metal fittings used in the transformer due to aging, and partial discharge occurs due to a tracking phenomenon caused by foreign substances attached to the surface, which increases the risk of transformer accidents. There was a problem.

Republic of Korea Patent Publication No. 10-1548358 (registration date: August 24, 2015) Republic of Korea Patent Publication No. 10-2018-0015861 (publication date: February 14, 2018)

The present invention was devised to solve the above problems. In order to prevent distortion and slippage of the packing, an integrated screw structure was used to maintain complete airtightness to prevent foreign substances from entering and leakage. It was tightened and fastened with a certain torque (kgfm). By uniformly distributing pressure in each area to prevent eccentricity, a separate flange tightening jig was applied to enable construction even by unskilled people, in order to shorten the fastening time, reduce costs, and prevent operator errors.

In addition, by coating the metal fittings used in high-pressure bushings with a nano-silicon compound, the corrosion resistance characteristics of the metal fittings are improved due to aging and the self-purifying properties prevent foreign substances from attaching to the surface, thereby preventing electrical safety accidents caused by tracking. did.

Meanwhile, other unspecified purposes of the present invention will be additionally considered within the scope that can be easily inferred from the detailed description and effects below.

In order to achieve this purpose, the high-voltage bushing attached to the top of the transformer is composed of a terminal clamp, an insulator, and an integrated flange, and the integrated flange is fixed to the lower part of the upper lid of the transformer by using a fixing method such as welding a female thread-shaped flange. By screwing together the male thread-shaped flange, the packing inserted into the top of the upper lid is prevented from being twisted and pushed out, and complete airtightness is maintained to prevent foreign substances and oil leaks. The flange is tightened so that anyone can easily tighten the flange. By using a jig to tighten the pressure distribution at the fastening area evenly with a constant torque, eccentricity was prevented, making construction easy even for unskilled people.

In addition, we attempted to prevent transformer safety accidents due to corrosion resistance and tracking phenomenon by applying coating using either a silicon compound material with nano-sized particles or nickel plating to the metal fittings used in the high-pressure bushing.

In the present invention, in order to prevent distortion and pushing of the packing, an integrated screw structure is used to maintain complete airtightness to prevent foreign substances and leakage, and to prevent eccentricity by tightening with a certain torque (kgfm) to ensure uniform pressure distribution at the fastening area. This not only reduces power outages and prevents electrical safety accidents, but also improves work convenience and improves stability using nano-silicon compound coating or nickel plating, thereby extending the life of the transformer and reducing replacement costs.

Figure 1. Conventional pole-mounted transformer
Figure 2. High pressure bushing of prior art
Figure 3. High pressure bushing of the present invention
Figure 4. Detailed view between the insulator and the upper lid of the present invention
Figure 5. Exploded view of the flange of the integrated screw structure used in the present invention
Figure 6. Cross-sectional view of the flange of the present invention
Figure 7. Cylindrical tightening jig of the present invention
Figure 8. Racket-type tightening jig of the present invention

Hereinafter, the present invention will be described in detail.

The present invention relates to a high-pressure bushing 100 for a transformer consisting of a clamp and an insulator, in which the lower part of the high-pressure bushing is inserted into the through hole of the upper lid 120, and the insulator 131 and the upper lid 120 are connected to the packing 136. It is in close contact with an integrated flange 134 in which a female threaded flange 1342 is fixed to the lower part of the upper lid and a male threaded flange 1341 with a square groove is coupled to the groove of the lower part of the high pressure bushing and a circular spring ( 133) is inserted, and the flange 134 has a structure that is in closer contact with the upper lid 120 by the spring 133 when fastened by the tightening jig 200 composed of a square protrusion 201. It relates to a flange for fastening a transformer high-pressure bushing, characterized in that.

As shown in Figure 3, a terminal clamp 300 for clamping the wire is attached to the upper part of the high-pressure bushing, and the terminal clamp 300 is configured to tightly adhere the wire by rotating and tightening.

In addition, Figure 3 shows that the high-voltage bushing coupled to the transformer upper lid 120 is an integrated flange 134 in which the terminal clamp 300, the insulator 131, and the female thread flange 1342 and the male thread flange 1341 are screwed together. It consists of

At this time, the female screw flange 1341 is fixed to the lower part of the upper lid using a welding or fixing method, and after the lower part of the high pressure bushing is inserted into the through hole of the transformer upper lid 120, the male screw flange 1342 is screwed. It is connected using a flange tightening jig to prevent distortion and pushing of the packing 136 inserted between the insulator and the upper part of the upper lid, and to prevent eccentricity by uniformly distributing pressure at the fastening area. .

In addition, Figure 4 shows that the insulator and the upper lid 120 are in close contact with the packing 136 in between to prevent the oil inside the transformer from leaking.

In the present invention, the assembly sequence of the high pressure bushing is to insert the packing into the lower part of the insulator, then insert the lower part of the high pressure bushing into the through hole formed in the upper lid, and attach the female threaded flange and the male threaded flange fixed to the transformer upper lid 120 by welding, etc. 1342) is tightened by screwing, and a circular spring is inserted into the circular groove formed in the lower part of the high-pressure bushing. When fastening the male screw flange (1342) using a tightening jig, the upper lid of the transformer is tightened by the elasticity of the spring and the role of a preventive jaw. (120) can be tightly fastened to maintain complete confidentiality and prevent foreign substances from entering and leaking.

In addition, the horizontal surface of the male screw flange was configured to have two or more square grooves, and the protrusion of the tightening jig was pressed into the grooves so that it could be fastened.

As shown in Figures 7 and 8, the tightening jig has a cylindrical shape or a racket (table tennis or tennis racket) shape and consists of two or more square-shaped protrusions at the bottom to fit into the square jig groove 137 of the male thread flange. The upper part of the cylindrical tightening jig has a hexagonal protrusion so that it can be easily tightened by rotating the tightening jig.

In addition, Figure 6 shows a cross-sectional view of the male and female threaded flanges 134. Specifically, the male threaded flange 1341 is threaded on the female threaded flange 1342 attached by welding to the lower part of the upper lid 120 like the welding portion 138. It is made by rotating and combining, and between the female thread flange 1342 and the male thread flange 1341, a packing (136) can be inserted and a groove into which the female thread can adhere is formed, and the male thread flange 1341 has a square or A polygonal jig groove 137 is formed so that the protrusion of the tightening jig can be inserted to enable tightening. In addition, a seating groove 139 is provided at the lower part of the male screw flange 1341 so that the spring 133 can be seated and tightly adhered. This must be formed.

In addition, the metal fittings used in high-voltage bushings were coated using a silicon compound material with nano-sized particles to provide surface insulation and corrosion resistance, and to prevent transformer safety accidents due to tracking phenomenon.

In the case of metal fittings that do not require insulation, corrosion can be prevented by plating 5㎛ or more using nickel or zinc.

The above silicone compound coating is attached at a certain thickness to the metal surface or tightening jig of the high pressure bushing used in the present invention to provide various mechanical and chemical properties such as self-cleaning properties, corrosion resistance, contamination resistance, non-flammability properties, and high surface hardness properties. In order to provide properties, the coating method of the present invention will be described in detail below.

The silicone compound coating material of the present invention is sodium oxide (Na ₂ O), an alkali metal oxide (M ₂ O:x ₁ Na ₂ O+x ₂ K ₂ O+x ₃ Li ₂ O) represented by the following chemical formula, oxidation Contains at least one of potassium (K ₂ O) and lithium oxide (Li ₂ O); inorganic acid compounds; and water (H ₂ O);

[Chemical formula] (x ₁ Na ₂ O+x ₂ K ₂ O+x ₃ Li ₂ O)·ySiO ₂ ·nH ₂ O

In the above formula (x ₁ Na _{2 O} +x ₂ K ₂ O+ _{x 3 Li 2} O _{) ·} ySiO _{2 ,} 0, x ₁ x ₂ +x ₃ ), satisfies yX.

In 100 parts by weight of the nano-inorganic material ((x ₁ Na ₂ O+x ₂ K ₂ O+x ₃ Li ₂ O)·ySiO ₂ ·nH ₂ O) expressed by the above formula, (M ₂ O+ySiO ₂ ) is 0.1 It is characterized in that it contains ~10 parts by weight and 0.01~2 parts by weight of an inorganic acid compound and the remainder is water.

The material expressed by the above chemical formula may additionally contain dispersants, catalysts, surfactants, etc. depending on the required functionality, coating method, and coating device.

Changes to the material according to the above coating device may vary depending on the pretreatment equipment. In particular, surfactants are included depending on the hydrophilicity of the base material surface to improve adhesion characteristics (leveling) and to improve dispersion of color pigments for color. Additional dispersants may be included to reduce material production time and accelerate chemical reactions.

The amount of the added solvent (water + inorganic acid compound) is greater than the solubility of the added alkali metal oxide in the solvent, and the inorganic acid compound is mainly phosphoric acid or boric acid.

The nano silicon compound material of the present invention can be manufactured containing one, two, and all three of x ₁ Na ₂ O, x ₂ K ₂ O, and x ₃ Li ₂ O represented by the above chemical formula. That is, the present invention includes at least one of the alkali metal oxides shown in the above formula, thereby increasing the adhesion or adhesion to the base material and improving the easy-clean properties, anti-fouling properties, water resistance, and mechanical and chemical properties of the coating thin film. It is possible to implement nano-inorganic materials that improve various high functionality, including:

The base material used in the present invention can be used for various base materials such as all metals and non-ferrous metals used in transformers, other plastics (polymer materials), films, ceramics, tiles, stone, and wood, in addition to the high-voltage bushings described above.

In order to coat the silicon compound coating material on the surface of the high pressure bushing metal fitting, pretreatment to remove foreign substances on the surface of the metal fitting may be necessary, and various pretreatments such as water cleaning using an alkaline cleaner, acid cleaning, plasma, and sandblasting are possible. .

After the above pretreatment process is completed, in the case of water cleaning, an air shower may be necessary to remove moisture caused by water. Afterwards, the silicone compound coating material manufactured above is attached using various coating methods and the coating is applied through heat treatment at 300 ± 50°C. It can be completed. The method of attaching the silicone compound coating material is to use any one of the following methods, such as applying with a brush, sponge, brush, or a soft cloth in addition to the spray method, or by using more than one method simultaneously to coat the surface of the base material with the silicone compound. Materials can be coated. At this time, it is preferable that the coating film of the silicon compound coating material coated on the surface of the amorphous alloy is coated to a thickness of 10 nm to 5 μm. All of the above coating methods will be able to control the coating thickness within the above range depending on the application.

The relational formula for the conditions for forming the coating film using the spray method is as follows.

H _t : coating thickness

Q: Flow rate (ul/min)

C: Viscosity or concentration (solids content)

U: Movement speed of base material (m/min)

t: number of coatings

W: spray area (m2)

h: Height of nozzle (m)

In the case of 0.1m min), nozzle height (0.05 ~ 1m), and number of coatings can be used to create coating layers of various thicknesses.

100: Pole-phase transformer
120: Top lid of columnar transformer
130: high pressure bushing, 131: insulator, 133: spring, 134: flange, 135: bolt, 136: packing, 137: jig groove, 138: weld, 139: spring seating groove
1341: male thread flange, 1342: female thread flange
200: tightening jig, 201: tightening jig protrusion
300: terminal clamp

Claims (8)

In the high-pressure bushing 100 for a transformer consisting of a clamp and an insulator, the lower part of the high-pressure bushing is inserted into the through hole of the upper lid 120, and the insulator 131 and the upper lid 120 are in close contact with the packing 136. , a female threaded flange 1342 is fixed to the lower part of the upper lid, an integrated flange 134 to which a male threaded flange 1341 having a square groove is coupled, and a circular spring 133 is located in the groove of the lower part of the high pressure bushing. It is inserted, and the flange 134 contains at least one of alkali metal oxide (M ₂ O), sodium oxide (Na ₂ O), potassium oxide (K ₂ O), and lithium oxide (Li ₂ O), and has an amount of 0.1 to 10. parts by weight; 0.01 to 2 parts by weight of an inorganic acid compound; and the remaining water (H ₂ O); coated with a silicone compound material of [chemical formula] (x ₁ Na ₂ O+x ₂ K ₂ O+x ₃ Li ₂ O)·ySiO ₂ ·nH ₂ O, A flange for fastening a transformer high-pressure bushing, characterized in that it has a structure that is in closer contact with the upper lid 120 by the spring 133 when fastened by the tightening jig 200 composed of a square protrusion 201.

According to clause 1,
The tightening jig 200 is a flange for fastening a transformer high-pressure bushing, characterized in that it has a cylindrical shape.
According to clause 1,
The tightening jig 200 is a flange for fastening a transformer high-pressure bushing, characterized in that it has a racket shape.
According to clause 1,
The female threaded flange (1342) is a flange for fastening a transformer high-pressure bushing, characterized in that it is fixed to the upper lid (120) by welding.
According to clause 1,
The flange 134 is a flange for fastening a transformer high-voltage bushing, characterized in that it is coated with a silicon compound material or nickel plated with a thickness of 5 μm or more.
delete According to clause 1,
A flange for fastening a transformer high-voltage bushing, characterized in that the thickness of the silicone compound coating material satisfies the following equation.

delete