JP6945709B2 - Gas insulation bushing - Google Patents

Description

The present invention relates to a gas-insulated bushing provided at the end of a gas-insulated device such as a gas-insulated switchgear (GIS).

As a configuration example of the conventional gas-insulated bushing, for example, there is one described in Patent Document 1. The gas insulation bushing is attached to the end of the gas insulation device, and is a porcelain tube filled with insulating gas inside the cylinder, a central conductor penetrating the inside of the porcelain tube, and an upper metal fitting attached to the tip of the porcelain tube. And have. The porcelain tube consists of an FRP (fiber reinforced plastic) tube and a polymer coating that coats the outer surface of the FRP tube.

Here, the upper metal fitting mainly has a function of sealing the insulating gas in the internal space of the porcelain tube and a function of connecting the porcelain tube and the central conductor to maintain the rigidity of the gas insulating bushing as a whole.

Japanese Patent No. 4540744

By the way, in the gas insulating bushing having the above-described configuration, since the upper metal fitting is exposed in the air, there is a possibility that corona discharge may occur from the upper metal fitting when the voltage becomes high. Therefore, as described in Patent Document 1, a configuration is often adopted in which a corona shield is performed by covering the upper metal fitting (flange metal fitting) with a shield ring.

However, when the shield ring is provided, it is necessary to provide the shield ring externally to the gas insulating bushing, and as a result, there is a drawback that the configuration becomes complicated and the size becomes large.

The present invention has been made in consideration of the above points, and provides a gas-insulated bushing having excellent flash characteristics and fouling characteristics while suppressing corona discharge without enlarging the configuration of the device. ..

One aspect of the gas-insulated bushing of the present invention is:
A porcelain tube having an insulating cylinder filled with an insulating gas inside and a polymer coating provided on the outer surface of the insulating cylinder.
A central conductor extending to the center of the porcelain tube and
An upper metal fitting airtightly attached to the tip of the insulating cylinder to seal the insulating gas,
In the gas insulation bushing attached to the gas insulation equipment
The upper metal fitting is attached to the tip of the insulating cylinder so that the outer peripheral surface coincides with the outer peripheral surface of the insulating cylinder.
The polymer coating covers the insulating cylinder and the upper metal fitting in a state where no step is formed at the joint between the insulating cylinder and the upper metal fitting.

According to the present invention, it is possible to realize a gas-insulated bushing having excellent flash characteristics and fouling characteristics while suppressing corona discharge without enlarging the configuration of the device.

Sectional drawing which shows the whole structure of the gas insulation bushing which concerns on embodiment Enlarged sectional view of the tip portion of the gas insulating bushing of the embodiment Cross-sectional view showing a configuration example of a conventional gas-insulated bushing

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view showing the overall configuration of the gas insulating bushing 10 according to the embodiment of the present invention. In the following, in the figure, the upper side is referred to as the front end side and the lower side is referred to as the rear end side. In the gas-insulated bushing 10 shown in FIG. 1, a gas-insulated device such as a gas-insulated switchgear is attached to the rear end side.

The gas-insulated bushing 10 has a porcelain tube 20, a center conductor 30, and an upper metal fitting (which may be referred to as an upper metal fitting) 40. The porcelain tube 20 is composed of a hard insulating cylinder (here, an FRP tube) 21 and a polymer coating 22 that covers the outer surface of the FRP tube 21. The inside of the FRP tube 21 is filled with an insulating gas 50 such as _{SF 6.}

The central conductor 30 is provided so as to extend to the center of the porcelain tube 20. The central conductor 30 is made of a conductive material suitable for energization, such as copper, aluminum, a copper alloy, or an aluminum alloy. The tip of the center conductor 30 is inserted into a recess on the rear end side of the upper metal fitting 40 and is connected to the upper metal fitting 40 by screwing, welding, or the like. Incidentally, a lead conductor 70 is integrally provided on the tip side of the upper metal fitting 40, and an overhead wire, a lead wire (not shown), etc. are connected to the lead conductor 70 by a fixed terminal (not shown) having a plate-shaped tip. Will be done. In the embodiment of FIG. 1, the drawer conductor 70 is inserted into the recess on the tip side of the upper metal fitting 40 and connected to the upper metal fitting 40 by screwing, welding, or the like, but the upper metal fitting 40 and the drawer conductor By manufacturing the 70 as a single component (integral object), the tip of the upper metal fitting 40 itself may be formed to be the lead conductor 70. A lead conductor 70 is integrally provided on the tip end side of the upper metal fitting 40 regardless of whether it is formed by connecting or integrally. The rear end of the center conductor 30 is connected to a gas-insulated device such as a gas-insulated switchgear.

The upper metal fitting 40 is attached to the tip of the FRP tube 21 and seals the insulating gas 50. The insulating gas 50 in the FRP tube 21 communicates with the insulating gas of a gas insulating device such as a gas insulated switchgear. Practically, the upper metal fitting 40 is attached to the FRP tube 21 by a method such as pressure welding or adhesive so that no gap is formed between the upper metal fitting 40 and the inner peripheral surface of the FRP tube 21. As a result, the airtightness of the insulating gas 50 is maintained. Further, the upper metal fitting 40 is connected to both the FRP tube 21 and the central conductor 30, whereby the rigidity of the gas insulating bushing 10 as a whole is maintained.

A shielding metal fitting 60 is provided at the rear end of the gas insulating bushing 10. The shielding metal fitting 60 has a cylindrical portion 61 that is inserted into the rear end of the FRP tube 21 and is connected to the FRP tube 21, and a flange portion 62 that extends radially outward from the rear end of the cylindrical portion 61. The cylindrical portion 61 has an electric field relaxation function because the tip portion is formed in an arc shape in cross section, and relaxes the electric field of the gas insulating bushing 10. The flange portion 62 is placed on the case C of a gas insulating device such as a gas insulated switchgear. An annular concave groove (not shown) is formed on either one of the contact surfaces between the flange portion 62 and the case C of the gas insulating device, and a sealing member such as an O-ring or packing (not shown) is formed in the concave groove. ) Is arranged and connected by a connecting member V such as a bolt, so that the gas insulating bushing 10 is airtightly fixed to the gas insulating device.

The insulating cylinder 21 is formed of a hard insulator, requires a predetermined mechanical strength as the gas insulating bushing 10, and needs to be airtight so that it can be airtightly bonded to the upper metal fitting 40 and the shielding metal fitting 60, respectively. Is. As a material satisfying these, an FRP tube is preferable, and in the present embodiment, the insulating cylinder 21 will be described as an FRP tube 21.

The polymer coating 22 is made of a material having excellent electrical insulation performance (for example, a polymer material such as a silicone polymer). The polymer coating 22 has a body portion that covers the outer periphery of the FRP tube 21, and a plurality of umbrella-shaped folds that are formed on the outer periphery of the body portion so as to be spaced apart from each other in the longitudinal direction. In FIG. 1, a plurality of umbrella-shaped folds having different protrusion lengths (long and short) are alternately formed so as to be separated from each other in the longitudinal direction, but the protrusion lengths of the folds may be the same.

In the case of the present embodiment, the polymer coating body 22 covers the flange metal fitting upper metal fitting 40 together with the FRP tube 21. Specifically, the polymer coating 22 completely covers the side surface and the upper surface of the upper metal fitting 40. This makes it possible to prevent the occurrence of corona discharge from the upper metal fitting 40.

Incidentally, FIG. 3, which is shown by assigning the same reference numerals to the portions corresponding to those in FIG. 1, shows a configuration example of a conventional gas-insulated bushing. As can be seen from FIG. 3, in the conventional gas-insulated bushing 10', the upper metal fitting 40' is exposed in the air, so that a corona discharge may occur from the exposed portion.

Further, in the conventional gas insulating bushing 10', the outer peripheral surface of the upper metal fitting 40' is attached to the tip of the FRP tube 21 so as to coincide with the outer peripheral surface of the body portion excluding the folds of the polymer coating 22'. On the other hand, in the gas-insulated bushing 10 of the present embodiment, the outer peripheral surface of the upper metal fitting 40 is attached to the tip of the FRP tube 21 so as to coincide with the outer peripheral surface of the FRP tube 21. As a result, the polymer coating body 22 attaches the FRP tube 21 and the upper metal fitting 40 to the FRP tube 21 and the upper metal fitting 40 in a state where a step is not generated at the joint between the FRP tube 21 and the upper metal fitting 40 so that the tip of the lead conductor 70 is exposed on the tip side. It is covered.

Further, as clearly shown in the enlarged cross-sectional view of FIG. 2, in the case of the present embodiment, a ring-shaped groove 70a and a ring-shaped protrusion are formed on the outer peripheral surface of the lead conductor 70 connected to the tip end side of the upper metal fitting 40. 70b is formed, and the polymer coating 22 is filled so as to enter the groove 70a. As a result, the tip of the polymer coating 22 bites into the groove 70a, so that an anchor effect can be obtained. As a result, peeling from the end portion of the polymer coating 22 can be prevented, so that the adhesive strength at the interface between the drawer terminal 70 and the polymer coating 22 can be improved.

Further, even when a fixed terminal (not shown) is inserted into the drawer conductor 70 by the ring-shaped protrusion 70b projecting in the radial direction of the lead conductor 70, the lower end of the fixed terminal hits the protrusion 70b and the fixed terminal is a protrusion. It can be prevented from being inserted on the rear end side of 70b. Therefore, there is no possibility of damaging the polymer coating 22 by inserting the fixed terminal.

In the case of the present embodiment, the ring-shaped groove 70a is formed so as to be adjacent to the rear end side of the ring-shaped protrusion 70b. As a result, the effects of both the groove 70a and the protrusion 70b can be obtained without lengthening the lead conductor 70.

Further, in the case of the present embodiment, the corner portion 22a on the tip end side of the polymer coating body 22 covering the upper metal fitting 40 has a curved shape such that the diameter is gradually reduced. As a result, since the tip of the polymer coating 22 has a tapered shape, rainwater and the like do not collect and flow to the lower side (rear end side) as compared with the case where the corners are formed at right angles, for example, so that the fouling performance is improved. Can be done.

As described above, according to the present embodiment, the porcelain tube 20 having the FRP tube 21 filled with the insulating gas 50 inside and the polymer coating 22 provided on the outer surface of the FRP tube 21 and the porcelain tube A central conductor 30 extending to the center of 20 and an upper metal fitting 40 that is airtightly attached to the tip of the FRP tube 21 and seals the insulating gas 50 are provided, and the polymer coating 22 is provided with the FRP tube 21 and the flange metal fitting upper metal fitting 40. By covering the above, the corona discharge from the upper metal fitting 40 can be suppressed. As a result, the shield ring that covers the upper metal fitting 40 becomes unnecessary.

However, a shield ring may be provided. In the configuration of the gas-insulated bushing of the present embodiment, the conductor exposed in the air on the tip side is a drawer conductor 70 having a diameter smaller than that of the upper metal fitting 40, and the upper metal fitting 40 is covered with the polymer coating 22. Therefore, even when the shield ring is provided, the shield ring that is smaller than the conventional one can be used due to the effect of suppressing the corona discharge by the polymer coating body 22. That is, even when the shield ring is provided, it is sufficient to cover the central conductor 30, so that the shield ring having a smaller diameter than the shield ring attached to the gas insulating bushing in which the conventional upper metal fitting 40'is exposed is sufficient. It is possible to prevent the configuration from becoming large.

Further, since the polymer coating 22 covers the flange metal fitting upper metal fitting 40 together with the FRP tube 21, both the flashing characteristics and the fouling characteristics of the gas insulating bushing 10 are not required to increase the total length of the gas insulating bushing. The characteristics of can be improved.

In FIG. 1 of the present embodiment, the shielding metal fitting 60 in contact with the lower end portion of the polymer coating 22 from the lower end portion of the outer peripheral portion where the lead conductor 70 is exposed in the air (here, the lower end portion of the outer peripheral portion of the protrusion 70b). The distance L1 in the longitudinal direction to the upper end of the outer peripheral portion exposed in the air is the conventional distance L1 in FIG. 3 assuming that the total length of the gas insulating bushing 10'is the same as the total length of the gas insulating bushing 10 of FIG. The distance L2 in the longitudinal direction from the lower end of the outer peripheral portion where the upper metal fitting 40'is exposed in the air to the upper end portion of the outer peripheral portion where the shielding metal fitting 60 in contact with the lower end portion of the polymer coating 22'is exposed in the air. It can be formed longer (L1> L2) than that. Therefore, as compared with the conventional case of FIG. 3, in FIG. 1 of the present embodiment, the flash characteristics can be improved even if the total length of the gas insulating bushing is the same.

Further, the leakage distance between L1s in FIG. 1 (the creepage distance of the polymer coating 22, not the length of the straight line of L1) is the conventional figure 3 in the case where the total length of the bushing is assumed to be the same as that of FIG. It can be secured longer than the leakage distance between L2 (the creepage distance of the polymer coating 22', not the length of the straight line of L2), and the leakage distance can be increased without increasing the total length of the bushing. can.

Further, in the case of the present embodiment, a fold portion (the most advanced fold portion in FIG. 1 or FIG. 2) is also provided on the outer periphery of the joint between the FRP tube 21 and the upper metal fitting 40. The leakage distance can be further secured as compared with the gas insulating bushing 10'of 3.

Therefore, by ensuring a longer leakage distance than in the conventional case, it is possible to improve the fouling performance of the gas insulating bushing 10.

As a result, a compact and highly pressure-resistant gas-insulated bushing can be realized.

As described above, according to the configuration of the present embodiment, it is possible to realize the gas insulating bushing 10 which is further excellent in flashing characteristics and fouling characteristics while suppressing corona discharge without enlarging the configuration of the equipment.

The above-described embodiments are merely examples of embodiment of the present invention, and the technical scope of the present invention should not be construed in a limited manner by these. That is, the present invention can be implemented in various forms without departing from its gist or its main features.

In the above-described embodiment, the case where the FRP tube 21 is used as the insulating cylinder filled with the insulating gas is described, but the present invention is not limited to this, and mechanical strength and airtightness are desired as the insulating cylinder. Other high materials that meet the value may be used.

Further, in the above-described embodiment, the case where the ring-shaped groove 70a into which the polymer covering body 22 enters is formed on the outer peripheral surface of the drawer conductor 70 attached to the tip end side of the upper metal fitting 40 is not limited to this. When a drawer conductor of the upper metal fitting 40 extending from the upper metal fitting 40 toward the tip of the upper metal fitting 40 is formed (that is, when the drawer conductor 70 is integrally formed with the upper metal fitting 40), a ring is formed on the drawer conductor of the upper metal fitting 40. A shaped groove may be formed.

The present invention can be applied to a gas-insulated bushing provided at the end of a gas-insulated device such as a gas-insulated switchgear.

10, 10'Gas Insulated Bushing 20, 20'Insulated Cylindrical Body (FRP Tube)
22, 22'Polymer coating 30 Center conductor 40, 40'Upper metal fittings 50 Insulation gas 60 Shielding metal fittings 61 Cylindrical part 62 Flange part 70, 70' Drawer conductor 70a Groove 70b Protrusion

Claims (5)

A porcelain tube having an insulating cylinder filled with an insulating gas inside and a polymer coating provided on the outer surface of the insulating cylinder.
A central conductor extending to the center of the porcelain tube and
An upper metal fitting airtightly attached to the tip of the insulating cylinder to seal the insulating gas,
In the gas insulation bushing attached to the gas insulation equipment
The upper metal fitting is attached to the tip of the insulating cylinder so that the outer peripheral surface coincides with the outer peripheral surface of the insulating cylinder.
The polymer coating covers the insulating cylinder and the upper metal fitting in a state where no step is formed at the joint between the insulating cylinder and the upper metal fitting.
Gas insulation bushing. A porcelain tube having an insulating cylinder filled with an insulating gas inside and a polymer coating provided on the outer surface of the insulating cylinder.
A central conductor extending to the center of the porcelain tube and
An upper metal fitting airtightly attached to the tip of the insulating cylinder to seal the insulating gas,
In the gas insulation bushing attached to the gas insulation equipment
The polymer coating covers the upper metal fitting together with the insulating cylinder.
A ring-shaped protrusion protruding in the radial direction of the drawer conductor is formed on the outer peripheral surface of the drawer conductor integrally provided on the tip end side of the upper metal fitting.
Gas insulation bushing. A porcelain tube having an insulating cylinder filled with an insulating gas inside and a polymer coating provided on the outer surface of the insulating cylinder.
A central conductor extending to the center of the porcelain tube and
An upper metal fitting airtightly attached to the tip of the insulating cylinder to seal the insulating gas,
In the gas insulation bushing attached to the gas insulation equipment
The upper metal fitting is attached to the tip of the insulating cylinder so that the outer peripheral surface coincides with the outer peripheral surface of the insulating cylinder.
The polymer coating covers the insulating cylinder and the upper metal fitting in a state where no step is formed at the joint between the insulating cylinder and the upper metal fitting.
A ring-shaped protrusion protruding in the radial direction of the drawer conductor is formed on the outer peripheral surface of the drawer conductor integrally provided on the tip end side of the upper metal fitting.
Gas insulation bushing On the outer peripheral surface of the drawer conductor integrally provided on the tip end side of the upper metal fitting, a ring-shaped groove into which the polymer coating enters is formed adjacent to the protrusion on the rear end side of the protrusion.
The gas-insulated bushing according to claim 2 or 3. The corner portion on the tip end side of the polymer coating body covering the upper metal fitting has a curved shape that gradually reduces the diameter.
The gas insulating bushing according to any one of claims 1 to 4.

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