JPH07297054A - Transformer - Google Patents

Abstract

PURPOSE:To prevent the damage or an insulating stud, and improve breakdown voltage, when a tank deforms and an insulating barrier contracts. CONSTITUTION:In an insulating barrier 3 for electrically insulating and protecting a tank side wall plate 2 facing a winding part, a plurality of insulating boards 3a are inserted between a plurality of first insulating spacers 4, and an insulating stud 5 penetrating collectively the first insulating spacers 4 and the insulating boards 3a is fixed to the tank side wall plate 2. Second insulating spacers 9 are inserted between a plurality of the first insulating spacers 4. The second insulating spacer 9 is a little thicker than the insulating board 3, and smaller than a through hole 3b of the insulating board 3a through which the insulating stud 5 penetrates.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is applicable to 500 kV and 1000 kV.
The present invention relates to an ultra-high voltage such as V and a large capacity transformer, and particularly to a transformer having an insulating barrier structure on a tank wall.

[0002]

2. Description of the Related Art With the recent increase in power demand, 50
Ultra-high voltage power transmission of 0 kV class has been implemented, and at present, the practical application of 1000 kV class power transmission is being promoted. Such transformers installed in power plants and substations for ultra-high voltage transmission generally employ a bank configuration in which a plurality of single-phase units are combined and three-phase wiring is performed to form a three-phase unit.

In such a single-phase transformer, due to various transportation restrictions and an increase in capacity per unit, the transformer is made compact, but the electric stress in each part inside the transformer becomes very high. Therefore, various measures have been taken for electrical insulation. For example, as shown in FIGS. 4 and 5, between the winding and the tank inner wall plate, a plurality of sheets are provided between the outer high voltage winding 1 and the tank side wall plate 2 in order to improve the withstand voltage due to the oil gap subdivision. Insulation barrier 3 composed of insulation board
Is installed.

This insulating barrier 3 usually has a press board of several mm, and a plurality of sheets are shown in FIG. 5 while holding a predetermined gap in the tank side wall plate 2 facing the outer high voltage winding 1 by an insulating spacer 4. Thus, the insulating stud 5 and the insulating nut 6 are tightened and fixed. The insulating studs 5 and the insulating nuts 6 are usually formed from an insulating material such as reinforced wood made of wood or glass fiber reinforced epoxy resin. Tightening with insulation studs 5 is done with insulation burrs 3
Is performed at a plurality of positions, and is tightened at a plurality of positions inside the insulating barrier 3 as necessary.

The transformer contents body is carefully inserted and fixed in the tank after the insulating barrier 3 is attached to the tank side wall plate 2 as described above, the cover is placed, and then the transformer is degassed and transformed. Insulating oil is injected.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The transformer constructed as described above has the following problems. That is, as described above, after the insulating barrier 3 is attached to the tank side wall plate 2 with the insulating stud 5 and the insulating nut 6,
The transformer is vacuum degassed. Although the tank is manufactured so as to withstand vacuuming, a slight elastic deformation occurs during the vacuum processing, and the tank side wall plate 2 is deformed so as to be curved inside the tank as shown in FIG.

At this time, a tensile stress acts on the insulating board of the insulating barrier 3 as shown by an arrow, so that the insulating barrier 3 has a tensile stress.
A large bending stress is applied to the insulating stud 5 inserted through the through hole. This bending stress increases as the length of the insulating stud 5 increases, so that the voltage class is high.
Moreover, the larger the number of boards of the insulating barrier 3, the larger the transformer. Therefore, the insulating studs 5 may be damaged by vacuum treatment of the transformer, so it is necessary to have a highly rigid tank structure so that the amount of deformation of the tank in vacuum is small.

Further, since the insulating barrier 3 is contracted by removing moisture therein by the vacuum deaeration process and the oiling process of the transformer, the insulating barrier 3 is inserted through the through hole of the insulating barrier 3 as shown by an arrow in FIG. A large bending stress acts on the insulating stud 5. For this reason, the insulating stud 5 may be damaged by the contraction of the insulating barrier 3, and therefore it is necessary to have a structure in which the insulating stud 5 is not subjected to an excessive bending stress even when the insulating barrier 3 contracts.

The present invention has been made in consideration of the above circumstances, and has an insulating barrier structure in which the withstand voltage performance is improved without damaging the insulating stud even when the tank is deformed or the insulating barrier is contracted. The purpose is to provide a transformer.

[0010]

In order to solve the above-mentioned problems, according to claim 1 of the present invention, a winding part wound around an iron core is housed in a tank, and the tank is opposed to the winding part. In a transformer provided with an insulating barrier for electrically insulating and protecting a side wall plate, the insulating barrier has a plurality of insulating boards inserted through a plurality of first insulating spacers, and the first insulating spacers and the insulating boards. An insulating stud that integrally penetrates the tank side wall plate is fixed to the tank side wall plate, and the insulating stud slightly thicker than the insulating board and provided on the insulating board between each of the plurality of first insulating spacers. It is characterized in that it is configured by interposing a second insulating spacer having an outer shape smaller than the hole penetrating therethrough.

According to a second aspect of the present invention, the second insulating spacer according to the first aspect has a large diameter portion and a small diameter portion, the small diameter portion being smaller than the insulating stud through hole, and the large diameter portion being It is larger than the through hole of the insulating stud.

According to a third aspect of the present invention, there is provided a transformer in which a winding part wound around an iron core is housed in a tank, and an insulating barrier for electrically insulating and protecting a tank side wall plate facing the winding part is provided. In the insulating barrier, a plurality of insulating boards are inserted through a plurality of first insulating spacers, and insulating studs that integrally penetrate the first insulating spacers and the insulating boards are fixed to the tank side wall plate. A polymer material spacer is inserted between the insulating spacer and the insulating board.

According to a fourth aspect, the polymer material spacer according to the third aspect is at least one selected from polyethylene terephthalate, polypropylene, polyphenylene sulfide, polyimide, polyethylene naphthalate, fluororesin, and glass-reinforced fiber plastic. It is characterized by being formed.

[0014]

According to the first aspect of the present invention, tensile stress is applied to the insulating board and bending stress is applied to the insulating stud due to tank deformation due to evacuation of the tank and dehydration / contraction of the insulating board due to vacuum deaeration and lubrication. Although it works, a second insulating spacer, which is slightly thicker than the thickness of the insulating board and has an outer shape smaller than the insulating stud through hole of the insulating board, is inserted between each of the plurality of first insulating spacers, so that insulation is achieved. The board is retractable. Therefore,
It is possible to prevent damage to the insulating studs without applying a force other than bending stress due to the weight of the insulating board to the insulating studs.

According to a second aspect, the second aspect of the first aspect is provided.
Of the insulating spacer has a large diameter portion and a small diameter portion, and the small diameter portion is smaller than the insulating stud through hole, and the large diameter portion is larger than the insulating stud through hole. The board can be expanded and contracted, and the positioning of the second insulating spacer can be facilitated when the insulating barrier is assembled.

According to the present invention, the polymeric material spacer is interposed between the insulating spacer and the insulating board, so that the friction coefficient between the insulating spacer and the polymeric material spacer and between the insulating board and the polymeric material spacer is increased. When the insulation board becomes smaller and an excessive tensile force is applied to the insulation board, the insulation board slips. As a result, it is possible to prevent excessive bending stress from acting on the insulating stud.

In a fourth aspect, the polymer material spacer according to the third aspect is at least one selected from polyethylene terephthalate, polypropylene, polyphenylene sulfide, polyimide, polyethylene naphthalate, fluororesin, and glass-reinforced fiber plastic. Is preferably formed from

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view showing a state in which an insulating barrier is attached to a tank side wall plate in the first embodiment of the transformer according to the present invention. Note that the same or corresponding portions as those of the conventional configuration will be described using the same reference numerals. And
As in the conventional structure, the high-voltage winding wound around the iron core is housed in the tank, and the insulating barrier 3 is attached to the tank side wall plate 2 facing the high-voltage winding. The board 2 is electrically insulated and protected.

As shown in FIG. 1, the insulating barrier 3 is several meters long.
A plurality of insulating boards 3a having a thickness of m are arranged in parallel with each other with a gap, and each of the plurality of insulating boards 3a has a through hole 3b through which the insulating stud 5 is inserted. One end of the insulating stud 5 is fixed to a fixed seat 7 provided on the tank side wall plate 3, while a plurality of insulating boards 3a are inserted into the insulating stud 5 through the through holes 3b, and the holding plate 8 is attached to the other end of the insulating stud 5. By tightening the insulation nut 6 via the, the plurality of insulation boards 3a are fixed. Here, each gap of the insulating board 3a is ensured to have a predetermined size by inserting an insulating spacer 4 as a first insulating spacer.

The insulating stud 5 of the insulating board 3a
An insulating spacer 9 as a second insulating spacer having an outer diameter smaller than its aperture and a thickness slightly thicker than that of the insulating board 3a is disposed in the through hole 3b for tightening and fixing. The insulating spacer 4 may be formed for each insulating stud, or may be formed as a common rod-shaped spacer between the same insulating boards 3a.

The insulating barrier structure constructed as described above operates as follows. That is, when the inside of the transformer tank is subjected to vacuum deaeration, the tank receives a force f toward the inside as shown in FIG. 6, and a slight elastic deformation occurs. For this reason, the insulating studs 5 fastened to the tank side wall plate 2
Tends to move outward with respect to the deformed portion of the tank side wall plate 2, but is pulled inward by the insulating board 3a,
Bending stress acts.

Further, since the moisture contained in the insulating board 3a is removed by the vacuum degassing process and the oiling process, the insulating board 3a shrinks. Therefore, even after the vacuum break of the tank, the insulating stud 5 is pulled by the insulating board 3a as shown in FIG. 7, and bending stress acts.

Since this bending stress is proportional to the length of the insulating stud 5 and the amount of change in the tank side wall plate 2 caused by evacuation or the amount of contraction of the insulating board 3a, tightening / fixing with the insulating stud 5 as in the present embodiment. Insulation board 3
By inserting the second insulating spacer 9 having an outer diameter smaller than the diameter and slightly thicker than the insulating board 3a, the insulating board 3a can be freely deformed. it can.

As a result, only the force due to the weight of the insulating board 3a acts on the insulating stud 5, and an excessive bending stress does not act. It is desirable that the size of the through hole 3b of the insulating board 3a be large enough to absorb the amount of tank displacement due to vacuuming or the amount of shrinkage of the insulating board 3a due to removal of water.

As described above, according to this embodiment, the through hole 3 of the insulating board 3a for tightening and fixing the insulating stud 5 is used.
b, the outer diameter is smaller than the diameter, and the insulating board 3
By inserting the second insulating spacer 9 that is slightly thicker than the thickness of a, the bending stress acting on the insulating stud 5 due to the tank displacement due to the vacuum processing, the vacuum deaeration processing, and the contraction of the insulating board 3a due to the oiling processing is applied. It can be removed, thus preventing damage to the insulating stud 5.

FIG. 2 is a transverse sectional view showing a state in which the insulating barrier is attached to the tank side wall plate in the second embodiment of the transformer according to the present invention. The same parts as those in the first embodiment will be described with the same reference numerals. The same applies to the following examples.

The present embodiment is different from the above-described first embodiment in that the shape and dimensions of the second insulating spacers inserted between the insulating spacers 4 are different. That is,
The second insulating spacer 10 shown in FIG. 2 has a convex portion,
It has a large diameter portion 10a having a large outer diameter dimension and a small diameter portion 10b having a small outer diameter dimension. The small diameter portion 10b is smaller than the through hole 3b of the insulating board 3a, and the thickness of the small diameter portion is the thickness of the insulating board 3a. On the other hand, the large diameter portion 10a having a large outer diameter is made larger than the through hole 3b of the insulating board 3a while being made slightly thicker.

As a result, after the insulating barrier 4 is assembled, the insulating barrier 4 can freely expand and contract, and
When assembling the insulating barrier 4, the positioning for the placement of the second spacer 10 is facilitated.

FIG. 3 is a cross sectional view showing a state in which an insulating barrier is attached to a tank side wall plate in a third embodiment of the transformer according to the present invention. The present embodiment is different from the above-described first and second embodiments in that a polymer film 11 as a polymer material spacer having a smooth surface is interposed between the insulating board 3a and the insulating spacer 4. It is a point. That is, as shown in FIG. 3, a tensile force is generated in the insulating board 3a due to the displacement of the tank caused by vacuuming, the insulating board 3a being vacuum-deaerated, the contraction caused by oiling, etc. Try to work.

However, the insulating board 3a is fastened and fixed to the tank side wall plate 2 by the insulating stud 5 and the fastening nut 6, but the action of the polymer film 11 causes a high gap between the polymer film 11 and the insulating board 3a. Since each coefficient of friction between the molecular film 11 and the insulating spacer 4 becomes small, when an excessive tensile force acts on the insulating board 3a, the insulating board 3a slips, and as a result, the insulating stud 5 becomes excessively large. It is possible to prevent bending stress from acting.

As the material of the polymer film 11, PET (polyethylene terephthalate), PP (polypropylene), PPS (polyphenylene sulfide), PI (polyimide), PE having relatively high mechanical strength is used.
Friction such as N (polyethylene naphthalate), PFA (perfluoroalkoxy fluorocarbon resin), FEP (fluoroethylene propylene copolymer), ETFE (ethylene tetrafluoride ethylene copolymer), PTFE (polytetrafluoroethylene) Fluorine-based resin having a particularly small coefficient, FRP (glass reinforced fiber plastic) having high mechanical strength, and the like can be mentioned, and it is preferable to be formed from at least one selected from these.

In this embodiment, the film-shaped spacer is used as the polymer material spacer, but the spacer is not limited to this and may be a thin plate-shaped spacer.

[0034]

As described above, according to the first aspect of the present invention.
According to the report, due to tank deformation due to vacuum evacuation of the tank and dehydration / contraction of the insulation board due to vacuum deaeration and lubrication, tensile stress acts on the insulation board and bending stress acts on the insulation stud. A little thicker than the thickness of the insulating board between each of the first insulating spacers,
Further, the second insulating spacer having a smaller outer shape than the insulating stud through hole of the insulating board is inserted, so that the insulating board can contract. Therefore, the insulation stud can be prevented from being damaged without exerting any force other than bending stress due to the weight of the insulation board on the insulation stud. As a result, withstand voltage performance is improved and a highly reliable transformer is provided. be able to.

According to a second aspect, the second insulating spacer according to the first aspect has a large diameter portion and a small diameter portion, and the small diameter portion is smaller than the insulating stud through hole and has a large diameter portion. Is larger than the through hole of the insulating stud, the insulating board can be expanded and contracted after the insulating board is assembled, and the second insulating spacer can be easily positioned at the time of assembling the insulating barrier, thereby improving the assembly efficiency.

According to the third aspect of the present invention, by inserting the polymer material spacer between the insulating spacer and the insulating board, each of the insulating spacer and the polymeric material spacer, and between the insulating board and the polymeric material spacer. When the coefficient of friction becomes small and an excessive tensile force acts on the insulating board, the insulating board slips. As a result, it is possible to prevent an excessive bending stress from acting on the insulating stud, and the same effect as in claim 1 can be obtained.

According to a fourth aspect, the polymer material spacer according to the third aspect comprises polyethylene terephthalate, polypropylene, polyphenylene sulfide, polyimide,
The same effect as in claim 3 can be obtained by using at least one selected from polyethylene naphthalate, fluorocarbon resin, and glass-reinforced fiber plastic.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state in which an insulating barrier is attached to a tank side wall plate in a first embodiment of a transformer according to the present invention.

FIG. 2 is a cross-sectional view showing a state in which an insulating barrier is attached to a tank side wall plate in the second embodiment of the transformer according to the present invention.

FIG. 3 is a cross-sectional view showing a state in which an insulating barrier is attached to a tank side wall plate in the third embodiment of the transformer according to the present invention.

FIG. 4 is a plan view showing a mounting state of a conventional insulating barrier.

FIG. 5 is a vertical cross-sectional view showing a mounting state of a conventional insulating barrier.

FIG. 6 is an explanatory diagram showing the deformation of the tank and the force acting on the insulating stud during vacuum deaeration in the tank.

FIG. 7 is an explanatory diagram showing a force that acts on an insulating stud when the insulating board contracts.

[Explanation of symbols]

 1 Outer High Voltage Winding 2 Tank Side Wall Plate 3 Insulation Barrier 3a Insulation Board 3b Through Hole 4 Insulation Spacer (First Insulation Spacer) 5 Insulation Stud 6 Insulation Nut 7 Fixing Seat 8 Holding Plate 9 Insulation Spacer (Second Insulation Spacer) 10 Insulating Spacer (Second Insulating Spacer) 10a Large Diameter Part 10b Small Diameter Part 11 Polymer Film (Polymer Material Spacer)

Claims (4)

[Claims] 1. A transformer in which a winding part wound around an iron core is housed in a tank and an insulating barrier for electrically insulating and protecting a tank side wall plate facing the winding part is provided. The burria inserts a plurality of insulating boards with a plurality of first insulating spacers, fixes insulating studs integrally penetrating the first insulating spacers and the insulating boards to the tank side wall plate, and A second insulating spacer, which is slightly thicker than the thickness of the insulating board and has an outer shape smaller than the hole through which the insulating stud is provided, provided on the insulating board. A transformer. 2. The second insulating spacer has a large diameter portion and a small diameter portion, the small diameter portion being smaller than the insulating stud through hole, and the large diameter portion being larger than the insulating stud through hole. The transformer according to claim 1, wherein: 3. A transformer in which a winding part wound around an iron core is housed in a tank, and an insulating barrier for electrically insulating and protecting a tank side wall plate facing the winding part is provided. In the barrier, a plurality of insulating boards are inserted through a plurality of first insulating spacers, an insulating stud that integrally penetrates the first insulating spacer and the insulating board is fixed to the tank side wall plate, and A transformer characterized in that a polymer material spacer is inserted between the insulating board and the insulating board. 4. The polymer material spacer comprises polyethylene terephthalate, polypropylene, polyphenylene sulfide, polyimide, polyethylene naphthalate,
The transformer according to claim 3, wherein the transformer is formed of at least one selected from a fluorine-based resin and a glass-reinforced fiber plastic.