JP2732720B2 - Stationary guidance equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[Object of the Invention]

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stationary induction device,
In particular, the present invention relates to a technique for improving the insulation strength of an electrostatic shield part attached to a winding end.

[0003]

2. Description of the Related Art In recent years, a gas-insulated transformer using gas as an insulating medium has been attracting attention as a transformer replacing an oil-filled transformer for disaster prevention reasons. There are various types of winding configurations of such a gas insulated transformer, for example, a gas insulated sheet wound transformer using a sheet winding. A sheet winding used in such a gas-insulated sheet-winding transformer is configured by winding a metal sheet and an insulating sheet in an overlapping manner.

FIG. 5 is a schematic cross-sectional view showing an example of such a gas-insulating sheet winding transformer. In FIG. 5, reference numeral 1 denotes a winding formed by superposing and winding a metal sheet and an insulating sheet, and is housed in a tank 2 together with an iron core 3 and an insulating gas. An electrostatic shield 4 is attached to the end of the winding 1 in order to reduce the electric field at the end of the metal sheet. On the other hand, although not shown, a lead wire from the winding 1 is connected to a bushing attached to the outside of the tank 2. In addition, the electrostatic shield 4
Is formed by applying an insulating coating 5 on a shield core made of a conductor. This insulating coating 5 is formed by winding an insulating tape many times.

[0005] Such an electrostatic shield 4 has, for example, a configuration as shown in FIG. In this case, FIG.
FIG. 6 is a schematic cross-sectional view showing an example of a configuration around an electrostatic shield 4 in the gas-insulated sheet winding transformer shown in FIG. 5. As shown in FIG. 6, a shield body 10 of the electrostatic shield is provided.
Is composed of a shield core 11 made of a conductive member and an insulating coating 12 provided on the outer periphery thereof. The insulating coating 12 is formed by winding an insulating tape many times on the shield core 11. This shield body 1
Insulating material 13 is provided at both ends in the winding axis direction
Is arranged. In addition, 14 in the figure is an insulating cylinder necessary for winding the winding 1.

[0006]

However, the configuration of the electrostatic shield in the conventional transformer as described above has the following problems.

That is, SF ₆ gas is usually used as an insulating medium of a gas insulating transformer. As is well known, SF ₆ gas causes an electric field-dependent dielectric breakdown.
If a gas gap exists in such an insulating gas, the electric field determined by Paschen's law of the gas causes dielectric breakdown of the gas. In this case, the gas gap when surrounded by an insulator
The electric field in the gas gap tends to increase due to the difference in the dielectric constant. In particular, since the electrostatic shield reduces the electric field at the end of the winding, it is often used in a portion where the electric field is high, and the electric field itself becomes high. Therefore, at the end of the electrostatic shield, it is necessary to reduce the gas gap as much as possible to reduce the electric field.

However, in order to meet such a need, an electrostatic shield having a configuration as shown in FIG.
Insulating coating 12 of shield body 10 and its winding direction
Between the insulator 13 disposed towards both ends, small wedge-shaped gas gap 15 is formed. For this reason, the electric field in the small wedge-shaped gas gap 15 becomes high, which may cause dielectric breakdown between the shield main body 10 and the insulator 13. Had become.

[0009] The above problem is not limited to the gas-insulated transformer, and similarly, in an oil-filled transformer in which an electrostatic shield is arranged at the end of a winding, a similar wedge is formed in the electrostatic shield part. A gap was formed, which was also a weak point on insulation. Further, not only the transformer but also other static induction devices such as a gas-insulated reactor and an oil-filled reactor are provided with a similar electrostatic shield, and have a similar problem.

The present invention has been proposed to solve the above-mentioned problems of the prior art, and an object of the present invention is to improve the insulation strength of an electrostatic shield portion at the end of a winding to improve reliability. An object of the present invention is to provide an excellent static induction device which has high performance and can contribute to a higher voltage.

[Structure of the Invention]

[0012]

SUMMARY OF THE INVENTION A transformer according to the present invention comprises:
The winding wound around the iron core is housed in a closed tank filled with insulating medium, and the winding winding axis of this winding is
In a static induction device in which an electrostatic shield for alleviating an electric field is arranged near both ends in the direction , the electrostatic shield is configured as follows. That is, claim 1
In the stationary induction device described above, the electrostatic shield is a shield body formed by applying an insulation coating around the outer periphery of a conductive member, and an insulating shield disposed by opposing crimping on both ends of the shield body in the winding axis direction . And a member.

In the stationary induction device according to the second to fourth aspects, the electrostatic shield has the following configuration in addition to the configuration according to the first aspect. The static induction device according to claim 2, wherein the electrostatic shield has a second insulating coating integrally covering the entire outer periphery of the electrostatic shield. The stationary induction device according to claim 3, wherein a flexible second insulating member is filled and disposed between at least both ends of the shield body in the winding axis direction and the insulating member. Have been. In the stationary induction device according to claim 4, the dielectric constant of the insulating member is lower than the dielectric constant of the insulating coating of the shield body.

[0014]

In the transformer according to the present invention having the above-described structure, the following effects can be obtained. In other words, according to the first aspect of the present invention, an insulating member is opposed to both ends of the shield body in the winding axis direction by pressure bonding, so that the insulation between the insulating coating of the shield body and the insulating member is formed. The occurrence of the gap itself can be prevented, so that dielectric breakdown due to the gap can be prevented, and the insulation strength between the insulating coating of the shield body and the insulating member can be improved.

According to the second aspect of the present invention, by providing the second insulating coating integrally covering the entire outer periphery of the electrostatic shield comprising the shield main body having the insulating coating and the insulating member, With the second insulating coating, a compressive force is applied between the shield body having the insulating coating and the insulating member, so that the generation of the gap can be effectively prevented. Therefore, dielectric breakdown due to the gap can be more effectively prevented, and the insulation strength between the insulating coating of the shield body and the insulating member can be further improved. In particular, in forming the second insulating coating, for example, a method of using an insulating tape or the like and winding the insulating tape many times while applying tension thereto is effective.

According to the third aspect of the present invention, the second insulating member having flexibility is filled and arranged between both ends of the shield body in the winding axis direction and the insulating member. With this second insulating member, it is possible to more effectively prevent the occurrence of a gap between the insulating coating of the shield body and the insulating member. Therefore, dielectric breakdown due to the gap can be more effectively prevented, and the insulation strength between the insulating coating of the shield body and the insulating member can be further improved. In particular, it is effective to use, for example, a gel material, an adhesive sealing material, a highly viscous liquid insulator, or the like as the second insulating member.

According to the fourth aspect of the present invention, the dielectric constant of the insulating member is made lower than the dielectric constant of the insulating coating of the shield body, so that the gap between the insulating coating of the shield body and the insulating member is reduced. Occurs, the electric field in the gap can be reduced because the dielectric constant of the insulating member is low. Therefore, the insulation strength between the insulating coating of the shield body and the insulating member can be improved.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a stationary induction device according to the present invention is applied to a transformer will be specifically described below with reference to FIGS.

First, FIG. 1 is a schematic sectional view showing a first embodiment in which a stationary induction device according to the present invention is applied to a gas-insulated sheet winding transformer. Is shown. Note that, in FIG.
The same reference numerals are given to the same parts as in the prior art, and the description is omitted.

As shown in FIG. 1, the shield body 10
Shield core 11 which is a conductive member and is subjected on its outer circumference and an insulating coating 12. This insulating coating 1
2 is formed by winding an insulating tape many times on a shield core (conductive member) 11. At both ends of the shield body 10 in the winding direction ,
A low-dielectric-constant insulator (insulating member) 16 having a dielectric constant lower than the dielectric constant of the insulating coating 12 is disposed so as to be pressed against the shield main body 10. In this case, the low dielectric constant insulator 1
The material of No. 6 is determined according to the material of the insulating coating 12.
Generally, the dielectric constant of polyethylene terephthalate, which is widely used as the material of the insulating coating 12, is about 3.2. In this embodiment, such a polyethylene terephthalate is used as the material of the insulating coating 12. In response to such a polyethylene terephthalate having a dielectric constant of about 3.2, as a material of the low dielectric constant insulator 16, for example, an olefin-based elastomer (dielectric constant of about 2.6) or polymethylpentene ( Dielectric constant about 2.1)
For example, a thermoplastic resin having a low dielectric constant is used. The contact surface of the low dielectric constant insulator 16 on the insulating coating 12 side is
The insulating coating 12 has a concave curved surface that matches the outer shape of the convex curved surface. Further, the outer periphery of the entire electrostatic shield including the shield main body 10 having the insulating coating 12 and the low dielectric constant insulator 16 is integrally covered with an external insulating coating (second insulating coating) 17. This outer insulating coating 17
Is a method in which a shield main body 10 having an insulating coating 12 and a low dielectric constant insulator 16 are wound many times around the entire surface thereof in a state where the convex curved surface and the concave curved surface are in contact with each other. It is formed by that.

The operation and effect of the first embodiment of the present invention having the above configuration are as follows. That is, since the low dielectric constant insulator 16 having a dielectric constant lower than the dielectric constant of the insulating coating 12 of the shield body 10 is used as an insulating member of the electrostatic shield, the insulating coating 12 and the low dielectric constant insulating material are used. Even if a gas gap occurs between the gas gap and the gas gap, the electric field in the gas gap can be reduced.

When the electric field in the gas gap portion between the insulating coating and the insulating member (filler) was calculated in order to investigate such an effect, the electric field calculation result as shown in FIG. 2 was obtained. FIG. 2 uses a dielectric constant of 3.2 corresponding to polyethylene terephthalate as the dielectric constant of the insulating coating, and uses an insulating member (filling) for such an insulating coating having a dielectric constant of 3.2. Is calculated in the case where the dielectric constant is changed stepwise.
In FIG. 2, the vertical axis indicates a specific electric field with respect to this reference value, where the electric field when the dielectric constant of the insulating member (filler) is 4.5 is 100.

As shown in FIG. 2, the electric field in the gas gap portion between the insulating member (filling) and the insulating coating changes according to the change in the dielectric constant of the insulating member (filling). It can be seen that the lower the dielectric constant of the member (fill), the lower the electric field concentration in the gas gap portion. The result is
In a gas insulating transformer using SF ₆ gas as an insulating medium, the lower the dielectric constant of the insulating member (filling) of the electrostatic shield, the higher the insulation strength can be improved.
Therefore, in the first embodiment in which the low dielectric constant insulator 16 having a lower dielectric constant than the insulating coating 12 of the shield body 10 is used as the insulating member of the electrostatic shield, a simple insulator is used. As compared with the related art, the insulation strength of the electrostatic shield part can be improved.

In the first embodiment, the shield core 11 having the insulating coating 12 and the low dielectric
The entire outer periphery of the outer insulating coating 17 is integrally coated with the outer insulating coating 17.
7, a compressive force can be applied between the shield main body 10 having the insulating coating 12 and the low dielectric constant insulator 16, so that the generation of a gap can be effectively prevented. Further, since the outer insulating coating 17 functions as a barrier, even if a partial discharge occurs between the shield main body 10 and the low dielectric constant insulator 16, the external insulating coating 17 can prevent the progress of the discharge.

Further, since the low dielectric constant insulator 16 is made of a thermoplastic resin, the low dielectric constant insulator 16 having various shapes can be easily formed by a mold. Therefore, as shown in FIG. 1, a low dielectric constant insulator 16 having a contact surface that can be in close contact with the insulating coating 12 of the shield body 10 can be easily provided.

Next, FIG. 3 shows the same as in the first embodiment.
FIG. 6 is a schematic cross-sectional view showing a second embodiment in which the stationary induction device according to the present invention is applied to a gas-insulated sheet winding transformer;
Particularly, the configuration around the electrostatic shield is shown. As shown in FIG. 3, in the second embodiment, the shield body 1
At both ends in the winding axis direction of the insulating coating 12 of the No. 0, an insulator 13 similar to the conventional one is disposed as an insulating member. Then, a second insulator 25 is disposed between the insulating coating 12 and the insulator 13. In this case, as the second insulator 25, for example, a silicone gel material, a silicone adhesive, or the like, which has tackiness and has a paste-like or flexible semi-solid property before use, A material that sticks with the passage of time is used. The second insulator 25 is inserted when forming the electrostatic shield.

The operation and effect of the second embodiment having the above configuration are as follows. That is, the gap between the insulating coating 12 and the insulator 13 can be filled with the second insulator 25. In particular, in the second embodiment, the second insulator 25 has a sticky property such as a silicon gel material or a silicone adhesive and has a paste-like or flexible semi-solid property before use. Since it is made of a material that adheres over time,
It has excellent adhesion between the insulator 2 and the insulator 13, and does not cause a gas gap between the insulating coating 12 and the insulator 13 even when manufacturing a transformer winding. Therefore, similarly to the first embodiment, the insulation strength of the electrostatic shield part can be improved. Before use, the second insulator 25 has a paste-like or flexible semi-solid property, and therefore does not need to be formed into a special shape. Because it can be easily arranged simply by inserting it between
There is also an advantage that can contribute to improving workability.

FIG. 4 is a schematic sectional view showing a third embodiment having a configuration in which the first and second embodiments are combined. That is, as shown in FIG. 4, in the third embodiment, similarly to the first embodiment, the shield body 1 is provided.
The low dielectric constant insulator 16 having a concave curved surface matching the convex curved surface of the insulating coating is disposed at both ends of the insulating coating 12 in the winding direction of the winding.
And are integrally covered by At the same time, a second insulator (second insulating member) 25 is arranged between the insulating coating 12 and the low dielectric constant insulator 16 and between the low dielectric constant insulator 16 and the external insulating coating 17. . In this case, as the material of the low dielectric constant insulator 16 and the outer insulating coating 17, the same materials as those of the first and second embodiments are used, respectively.

The insertion of the second insulator 25 in the third embodiment is performed, for example, as follows. That is, first, the second insulator 25 is adhered on the surface of the low dielectric constant insulator 16, and the shield body 10 having the insulating coating 12 is pressed against the second insulator 25, and the insulating coat 12 and the low dielectric constant insulator are pressed. 16 is brought into close contact. Next, an outer insulating coating 17 is formed by winding an insulating tape many times around the entire surface.

In the third embodiment having the above-described structure, the second insulator 25 attached on the surface of the low dielectric constant insulator 16 is compressed by air due to the compressive force applied when the outer insulating coating 17 is formed. Are extruded to fill the small gas gaps between the insulating coating 12 and the low dielectric constant insulator 16 and between the low dielectric constant insulator 16 and the external insulating coating 17. Therefore, similarly to the first and second embodiments, the insulation strength of the electrostatic shield part can be improved.

The present invention is not limited to the above embodiments, and the material of the low dielectric constant insulating member and the second insulating member used in the present invention can be appropriately selected. For example, a configuration in which a highly viscous liquid insulating material such as silicon oil is used as the material of the second insulating member is also possible. When such a liquid insulating material is used, it is possible to prevent the liquid insulating material from flowing out by providing an external insulating coating, as in the third embodiment. When such a liquid insulating material is used as the second insulating member, the liquid insulating material can be impregnated even between minute gas gaps between the insulating coatings, so that the insulating strength is further increased. Can be improved.

On the other hand, each of the above embodiments is an embodiment in which the present invention is applied to a gas-insulated transformer. However, the present invention is not limited to a gas-insulated transformer, The present invention can be similarly applied to a vessel, and can obtain an excellent effect. Further, the present invention is not limited to transformers, and can be similarly applied to other stationary induction devices such as gas-insulated reactors and oil-filled reactors,
Similarly, excellent effects can be obtained.

[0033]

As described above, in the present invention,
The insulation strength of the electrostatic shield part at the winding end can be improved as compared with the conventional one by pressing the shield body of the electrostatic shield and the insulating member against each other, which contributes to higher reliability and higher voltage. As a result, an excellent stationary guidance device can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a first embodiment in which a stationary induction device according to the present invention is applied to a gas-insulated sheet winding transformer.

FIG. 2 is a graph showing an electric field calculation result of a gap portion between an insulating coating and an insulating member (filling) when the dielectric constant of the insulating member (filling) of the electrostatic shield is changed stepwise.

FIG. 3 is a schematic sectional view showing a second embodiment in which the stationary induction device according to the present invention is applied to a gas-insulated sheet winding transformer.

FIG. 4 is a schematic cross-sectional view showing a third embodiment in which the stationary induction device according to the present invention is applied to a gas-insulated sheet winding transformer.

FIG. 5 is a schematic cross-sectional view showing an example of a conventional gas insulating sheet winding transformer.

FIG. 6 is a schematic cross-sectional view showing an example of a configuration around an electrostatic shield in the gas insulating sheet wound transformer of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Winding 4 Electrostatic shield 10 Shield main body 11 Shield core 12 Insulating coating 13 Insulating material 14 Insulating cylinder 15 Gas gap 16 Low dielectric constant insulating material 17 External insulating coating 25 Second insulating material

Claims (4)

(57) [Claims] In a closed tank filled with an insulating medium,
In a stationary induction device including a winding wound around an iron core and arranging an electrostatic shield for electric field relaxation near both ends of the winding in the axial direction of the winding , the electrostatic shield is , A shield body in which an insulating coating is applied to the outer periphery of the conductive member, and a winding winding of the shield body
A stationary induction device, comprising: an insulating member disposed so as to be opposed to and crimped at both axial ends. 2. The static induction device according to claim 1, wherein the electrostatic shield has a second insulating coating that integrally covers the entire outer periphery of the electrostatic shield. 3. Winding of at least the shield body
The stationary induction device according to claim 1, wherein a second insulating member having flexibility is filled and arranged between both ends in the axial direction and the insulating member. 4. The stationary induction device according to claim 1, wherein a dielectric constant of the insulating member is lower than a dielectric constant of an insulating coating of the shield body.