KR101172795B1

KR101172795B1 - composite bushing for decreasing electric field intensity

Info

Publication number: KR101172795B1
Application number: KR20100072143A
Authority: KR
Inventors: 조한구
Original assignee: 한국전기연구원
Priority date: 2010-07-26
Filing date: 2010-07-26
Publication date: 2012-08-09
Also published as: KR20120010542A

Abstract

The present invention relates to a bushing, in particular an ultra-high pressure bushing, comprising a FRP tube, an upper and a lower flange coupled to upper and lower ends of the FRP tube, and a housing formed outside the FRP tube. In order to suppress electric field concentration at the critical part connected to the enclosure, an inner shield made of metal is formed inside the FRP tube, and a semiconductive layer is formed on the inner surface of the FRP tube at a position corresponding to the upper end of the inner shield. An electric field relaxation-type composite bushing characterized by mitigating electric field concentration at a portion and an upper portion of the inner shield is a technical gist. As a result, it is possible to provide a bushing having high insulation performance by mitigating electric field concentration at a critical portion connected to an enclosure of a power device or at an interface at which each component is coupled to prevent damage to the FRP tube and deterioration of the external housing. .

Description

Composite bushing for decreasing electric field intensity

The present invention relates to a bushing, in particular an ultra-high pressure bushing, by providing a semi-conductivity in the fabrication of the inner shield and the FRP tube inside the FRP tube to mitigate the field concentration, the electric field in the critical region where the electric field is concentrated in the use of the ultra-high pressure bushing Field mitigation composite bushings to improve vulnerabilities.

In general, the bushing used in power devices (GIS, GCB, DS, etc.) is to insulate between the outer casing of the power device connected to the ground (ground) at the top of the high voltage applied.

1 shows a configuration of a conventional high voltage bushing, as shown, a high voltage bushing is basically a FRP tube 10, a housing 20 made of a polymer on the surface of the FRP tube and a metal flange 40, ( 50), which is generally referred to as a composite bushing different from a magnetic bushing.

First, the FRP tube 10 used for the bushing is manufactured by a filament winding process and has a cylindrical internal structure. The housing 20 is formed on the surface of the FRP tube 10 and a plurality of sheds 21 are formed to protrude to increase the leakage distance. In addition, a center conductor 30 is positioned at the center of the FRP tube 10, and upper and lower flanges 40 and 50 made of metal are positioned at both ends of the housing 20 and the FRP tube 10. .

In general, the upper flange 40 is in direct contact with the center conductor 30 has a high potential, while the lower flange 50 is in contact with the enclosure of the power equipment to be a shielded portion close to the ground (ground) And is mechanically connected to the FRP tube 10 by thermal fitting.

The shielding portion is generated in the lower portion of the bushing, that is, the portion connected to the ground of the enclosure of the power device, thereby causing electric field concentration at the lower side. Therefore, in order to suppress electric field concentration at the critical part of the bushing, an inner shield 60 made of metal is formed in the bushing.

The inner shield 60 is formed between the center conductor 20 and the FRP (10) tube to mitigate the electric field distribution, and is formed in a cylindrical shape along the vertical axis of the bushing, most of the equipotential inside the bushing is the inner shield ( 60) along the vertical axis, which has a structure capable of suppressing electric field concentration at the critical junction point, which is a weak point of the bushing.

However, the surface of the FRP tube 10 corresponding to the upper end of the inner shield 60 may cause a decrease in the dielectric strength of the FRP tube 10 due to the dense electric field as an electrically weak critical portion. Another electrical weakness is caused by causing electric field concentration, resulting in deterioration of the FRP tube 10 and damage of the outer housing 20 during long-term use of the bushing, thereby greatly deteriorating long-term reliability.

The present invention is to solve the above problems, by providing a semi-conductivity in the manufacture of the inner shield and FRP tube inside the FRP tube to mitigate the field concentration, in the critical region where the electric field is concentrated in the use of the ultra-high pressure bushing Its purpose is to provide a field-relaxing composite bushing that improves electrical vulnerabilities.

In order to achieve the above object, the present invention, in the bushing comprising a FRP tube, upper and lower flanges coupled to the upper and lower ends of the FRP tube, and a housing formed outside the FRP tube, In order to suppress electric field concentration at the connected critical portion, an inner shield made of metal is formed inside the FRP tube, and a semiconductive layer is formed on the inner surface of the FRP tube at a position corresponding to an upper end portion of the inner shield. An electric field relaxation-type composite bushing, characterized in that the electric field concentration at the upper end of the inner shield is alleviated, is a technical gist.

In addition, the semiconductive layer is preferably formed of a carbon black film in a tapered shape on the inner surface of the FRP tube, the width is 5 ~ 200mm range, the thickness of the glass roving (glass roving) thickness of the FRP tube It is preferable that it is 2-3 times.

In addition, the FRP tube, the lower flange and the outer shield is preferably formed outside the lower flange of the interface portion to which the housing is coupled, the outer shield is formed spaced apart from the shed of the housing, It is preferably formed higher than the upper end of the lower flange. In addition, the outer shield is preferably formed of the same material as the lower flange, the upper end is preferably formed in an annular shape.

Here, the inner shield is formed in the 'L' shape is preferably coupled to the receiving portion formed in the lower end of the lower flange bottom surface is formed integrally with the lower flange.

By the above configuration, the present invention, the inner shield is formed inside the FRP tube to suppress the electric field concentration at the critical portion connected to the enclosure of the power equipment, the peninsula to mitigate the electric field concentration at the upper end (A) of the inner shield By constructing a solenoid FRP tube, it is possible to improve electrical weakness in critical areas where electric fields are concentrated in the use of ultra high pressure bushings, and to produce a bushing having high insulation performance by preventing damage to the insulating tube and deterioration of the outer housing. There is.

In addition, by forming an outer shield to mitigate field concentration in critical areas such as the interface where FRP tubes, housings, and metal flanges meet, the electric field concentrated in this area is moved to the upper end to prevent deterioration due to prolonged use. It has the effect of improving the reliability of the bushing by improving the dielectric breakdown performance.

In addition, since the inner shield inside the bushing is manufactured integrally with the metal flange, it is possible to manufacture an effective bushing by shortening the working time and the trouble occurring when the power device is combined.

1-Cross-sectional view of a conventional bushing.
2-a sectional view of the main part of a field-relaxing composite bushing according to the invention;

The present invention relates to a composite bushing for the ultra-high voltage power device, as shown in Figure 2, the central conductor 300 is formed in the center and the FRP tube 100, the upper and lower ends of the FRP tube 100 An upper flange (not shown) coupled to the lower flange 500, and the housing 200 is formed on the outside of the FRP tube 100.

In particular, in order to suppress electric field concentration at the lower portion of the bushing, that is, the critical portion connected to the enclosure of the power equipment, the inner shield 600 made of metal in the upper axial direction inside the FRP tube 100 in the lower flange 500 is provided. A semiconducting layer 700 is formed on the inner surface of the FRP tube 100 at a position corresponding to the upper end A of the inner shield 600 so as to alleviate electric field concentration at the upper end A of the inner shield 600. ) Is formed.

Hereinafter, the FRP tube 100, the upper flange and the lower flange 500 and the housing 200 of the components of the present invention are the same as the conventional manufacturing method and form, and will not be described in detail, the interior The shield 600 and the semiconducting layer 700 will be described.

First, the inner shield 600 is formed of a metal material, the upper end portion (A) is made of a shape having a large corner radius, formed in the 'L' shape of the lower end receiving portion formed in the lower flange 500 Received and coupled to the 510 is formed integrally with the lower flange (500).

In general, in the case of the inner shield 600, the length and thickness of the inner shield 600 are determined for each manufacturer, and have different shapes according to the required electrical characteristics, so that an overlapping work process and an increase in cost are required. Since the shield 600 is manufactured integrally with the metal flange, it is possible to shorten the trouble and working time that occur when the power device is coupled with the power device.

The inner shield 600 is to be coupled to the receiving portion 510 formed on the bottom surface of the grounded lower flange 500, the receiving portion 510 is processed as the thickness of the inner shield 600 is fastened Even after the height of the lower flange 500 is to be formed integrally. The receiving portion 510 is positioned in front of the O-ring portion for airtightness between the flanges, and is connected to the inner shield 600 through two bolt coupling portions.

As described above, the semiconductive layer 700 is formed on the inner surface of the FRP tube 100 corresponding to the position of the upper end A of the inner shield 600, and is manufactured in the following manner.

The FRP tube 100 is manufactured by a filament winding method having a general single or multi winding angle. The FRP tube 100 is coated with a carbon black film, which is a conductive material, to a mandrel before the filament winding process. The semiconductive layer 700 is formed. The semiconducting layer 700 is formed in a tapered shape having a gap with an upper end A of the inner shield 600 on the inner surface of the FRP tube 100 to produce a semiconductive FRP tube 100. .

In detail, in the filament winding process, a polyester liner is first applied to a mandrel, and then a carbon black film, which is a semiconductive material, is partially adhered to the upper portion A of the inner shield 600. do. Thereafter, the FRP tube 100 is manufactured through glass roving having an arbitrary winding angle designed to withstand mechanical and internal pressures. The coating width of the carbon black film is related to the electric field concentration of the inner shield 600 and is manufactured in the range of 50 to 200 mm in consideration of the manufacturing process and cost, and the thickness of the film is about 2 to 3 times the thickness of the glass roving. Calculated and designed

That is, the semiconducting layer 700 is formed on the inner surface of the FRP tube 100 corresponding to the upper end A of the inner shield 600, and a polyester liner layer is formed therein, thereby concentrating the surface electric field of the bushing. It is designed to stabilize and electrically stabilize.

The use of the semiconductive FRP tube 100 effectively discharges the dense isoelectric potential in the critical region where the electric field is concentrated in the use of the ultra-high pressure bushing to improve the electrical weakness, damage of the FRP tube 100 and the outer housing It is possible to prevent the deterioration of the 200 to manufacture a bushing having a high insulation performance.

In addition, the outer shield (outside the lower flange 500 of the interface portion (B) to which the FRP tube 100 and the lower flange 500 and the housing 200 is coupled to the outer side of the lower flange 500 of the bushing ( It is desirable to further form 800, to mitigate field concentration in the stress zone of the bushing in the high voltage bushing.

In general, the most vulnerable part of the bushing is the interface part (B) where the FRP tube 100, the housing 200, and the metal flange meet each other, which causes long-term deterioration of this part when used for a long time, resulting in reliability problems due to insulation breakdown. do. Accordingly, the outer shield 800 is for suppressing electric field concentration at this portion of the bushing, and aims to relax the electric field at the interface by moving the concentrated electric field to the upper end of the outer shield 800.

The outer shield 800 is kept in a removed state during the end fitting (ending fitting) and the housing 200 injection in consideration of a manufacturing process, and then formed by assembling through a bolt.

In addition, the position of the outer shield 800 is formed on the outside of the lower flange 500 near the interface portion (B) where the FRP tube 100, the housing 200, the metal flange meets the shielding portion of the bushing, The height of the outer shield 800 has a minimum separation distance in consideration of the gap between the shed 210 of the housing 200 and is designed to be higher than the upper end of the lower flange 500. In addition, the material of the outer shield 800 is the same as the material of the lower flange 500, it is designed in a structure that suppresses the electric field concentration in the shape of the upper end of the annular electrode.

The present invention configured as described above can improve the electrical weakness in the critical region in which the electric field is concentrated in the use of the ultra-conductive FRP tube 100 by using the semi-conductive FRP tube 100 and damage the insulation tube and deterioration of the outer housing 200. This prevents the bushing with high insulation performance. In addition, the inner shield 600 inside the bushing may be manufactured integrally with the metal flange, thereby reducing the problems and working time occurring when the power device is combined with the bushing, thereby effectively manufacturing the bushing.

100: FRP tube 200: housing
210: Shed 300: Center conductor
500: lower flange 510: receiving portion
600: inner shield 700: semiconducting layer
800: outer shield

Claims

In the bushing including an FRP tube 100, an upper and lower flange 500 coupled to the upper and lower ends of the FRP tube 100, and a housing 200 formed outside the FRP tube 100,
In order to suppress electric field concentration at the critical part connected to the enclosure of the power device, an inner shield 600 made of metal is formed inside the FRP tube 100 and corresponds to an upper end A of the inner shield 600. A semiconducting layer 700 is formed on the inner surface of the FRP tube 100 at a position to mitigate electric field concentration at the critical portion and the upper end portion A of the inner shield 600,
The field relaxation type composite bushing, characterized in that the outer shield 800 is formed on the outer side of the lower flange 500 of the interface portion where the FRP tube 100, the lower flange 500 and the housing 200 is coupled. .

The method of claim 1, wherein the semiconducting layer 700,
The field relaxation type composite bushing, characterized in that formed in the tapered shape on the inner surface of the FRP tube (100).

The method of claim 2, wherein the semiconducting layer 700,
A field relaxing composite bushing, characterized in that formed from a carbon black film.

The method of claim 3, wherein the semiconducting layer 700,
The width is in the range of 5 ~ 200mm, the thickness of the field relaxation type composite bushing, characterized in that two to three times the thickness of the glass roving (glass roving) of the FRP tube (100).

delete

The method of claim 1, wherein the outer shield 800,
The field relaxation type composite bushing, characterized in that formed spaced apart from the shed 210 of the housing 200, than the upper end of the lower flange (500).

The method of claim 6, wherein the outer shield 800,
The field relaxation type composite bushing is formed of the same material as the lower flange 500, the upper end is formed in an annular shape.

According to any one of claims 1, 2, 3, 4, 6 and 7, wherein the inner shield 600 is formed in the 'L' shape so that the lower end of the lower flange (500) The field relaxation type composite bushing, which is coupled to the receiving portion 510 formed on the bottom surface and formed integrally with the lower flange 500.