JP6250965B2 - Resin insulated vacuum valve - Google Patents

Description

  Embodiments of the present invention relate to a resin-insulated vacuum valve in which the outer periphery of a vacuum valve is molded with an insulating material such as an epoxy resin.

  Recently, instead of a gas insulation system using an insulating gas such as SF6 gas, a solid insulation system switchgear using an epoxy resin has been adopted as an environmentally conscious type. Also in the vacuum valve, the outer periphery is molded with an epoxy resin to reinforce external insulation (see, for example, Patent Document 1).

  A resin-insulated vacuum valve of this type is shown in FIG. 4, and a disk-like fixed-side sealing metal fitting 2 and a movable-side sealing metal fitting 3 are provided at both ends of a cylindrical vacuum insulating container 1 made of alumina porcelain. Sealed. A fixed-side energizing shaft 4 is penetrated and fixed at the center of the fixed-side sealing fitting 2, and a fixed-side contact 5 is fixed to an end portion in the vacuum insulating container 1. Opposite to the fixed side contact 5, a movable side contact 6 that is detachable is fixed to the end of the movable side energizing shaft 7 that movably penetrates the central opening of the movable side sealing fitting 3. A free end of a telescopic cylindrical bellows 8 is sealed at an intermediate portion of the movable side energizing shaft 7, and a fixed end is sealed at a central opening of the movable side sealing fitting 3. A cylindrical arc shield 9 is provided on the outer periphery of the contacts 5 and 6 to capture the metal vapor. These constitute a vacuum valve.

  The fixed-side sealing fitting 2 is provided with a bowl-shaped fixed-side electric field relaxation shield 10 so as to surround the outer peripheral end portion. The fixed-side electric field relaxation shield 10 is in contact with the fixed-side sealing fitting 2 and is connected to the circular plate portion 10a and the circular plate portion 10a. The cylindrical portion is bent approximately 90 degrees and extends parallel to the axial direction. 10b, and is composed of a curved portion 10c having a U-shaped cross section that is connected to the cylindrical portion 10b and is bent with a predetermined curvature. A hook-like movable-side electric field relaxation shield 11 similar to the fixed-side electric field relaxation shield 10 is also provided at the outer peripheral end of the movable-side sealing metal fitting 3. The movable-side electric field relaxation shield 11 is connected to the disk-side portion 11a and the disk-shaped portion 11a that are spread in the radial direction with a predetermined distance from the movable-side sealing metal fitting 3, and is bent approximately 90 degrees to be parallel to the axial direction. The extended cylindrical part 11b is connected to the cylindrical part 11b, and is constituted by a curved part 11c having a U-shaped cross section bent with a predetermined curvature. The inner peripheral surfaces of the bending portions 10c and 11c are kept at a predetermined distance from the vacuum insulating container 1, respectively.

  A cylindrical resin intrusion prevention tube 12 is provided on the inner peripheral portion of the disc portion 11 a of the movable-side electric field relaxation shield 11 so as to surround the movable-side conductive shaft 7. A conductive O-ring 13 is provided between the movable side sealing fitting 3 and the disk portion 11a so that epoxy resin does not enter the movable side energizing shaft 7 side during molding. An insulating layer 14 molded with an epoxy resin is provided on the outer periphery of the vacuum valve. Both end portions of the insulating layer 14 are tapered interface connection portions. On the outer periphery of the insulating layer 14, a ground layer 15 to which a conductive paint is applied except for the interface connection portion is provided.

  Next, the molding will be described with reference to FIG.

  Although the fixed energizing shaft 4 and the movable energizing shaft 7 of the vacuum valve are fixed to the casting mold and the movable-side electric field relaxation shield 11 is mounted via the O-ring 13, the compression degree of the O-ring 13 is circumferential. If the direction is unstable, the disk part 11a and the movable side sealing fitting 3 may not be parallel. In FIG. 5, although exaggerated, the disk portion 11 a is downwardly shown in the figure. Then, on the right side, the compression of the O-ring 13 is small, the cylindrical portion 11b is inclined toward the ground layer 15 and the insulating thickness of the insulating layer 14 is reduced, leading to a decrease in the withstand voltage characteristic. On the left side, the O-ring 13 is greatly compressed, the interval between the curved portion 11c and the vacuum insulating container 1 is narrowed, forming a minute gap, the electric field strength is increased, and the internal stress is increased. For this reason, the movable-side electric field relaxation shield 11 can be disposed substantially parallel to the movable-side sealing metal fitting 3, and the insulating thickness of the insulating layer 14 and the distance from the vacuum insulating container 1 can be kept uniform over the entire circumference. What could be done was desired.

JP 2009-193734 A

  The problem to be solved by the present invention is that the disk portion 11a of the movable-side electric field relaxation shield 11 is disposed substantially parallel to the movable-side sealing fitting 3, and the insulating thickness of the insulating layer 14 and the distance from the vacuum insulating container 1 Is to provide a resin-insulated vacuum valve that can improve the insulation characteristics by keeping the electric field strength uniform over the entire circumference and suppressing the increase in electric field strength and internal stress.

In order to solve the above-described problems, a resin insulated vacuum valve according to an embodiment includes a vacuum insulated container, a pair of contactable and separable contacts, a vacuum valve having a sealing metal fitting, and a radius arranged to surround the sealing metal fitting. An electric field relaxation shield composed of a disc portion extending in a direction, a cylindrical portion connected to the disc portion and extending in the axial direction, a curved portion connected to the cylindrical portion and bent at an end, and the disc portion a is fixed, a first ring plate the entire circumference abut on the sealing fitting is provided in an outer periphery of the first ring plate, the entire periphery between the disc portion and the sealing fitting An elastic member to be compressed; an insulating layer provided on an outer periphery of the vacuum valve; and a grounding layer provided on an outer periphery of the insulating layer, wherein the first ring plate and the elastic member are at least the vacuum valve. It is used for the movable side of the.

The principal part expanded sectional view which shows the structure of the resin insulation vacuum valve which concerns on Example 1 of this invention. The principal part expanded sectional view which shows the structure of the resin insulation vacuum valve which concerns on Example 2 of this invention. The principal part expanded sectional view which shows the structure of the resin insulation vacuum valve which concerns on Example 3 of this invention. Sectional drawing which shows the structure of the conventional resin insulation vacuum valve. The principal part expanded sectional view which shows the structure of the conventional resin insulation vacuum valve.

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

  First, a resin insulated vacuum valve according to Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 is an enlarged cross-sectional view of a main part showing the configuration of a resin-insulated vacuum valve according to Embodiment 1 of the present invention. Note that the configuration of the resin-insulated vacuum valve is the same as that of the prior art except for the movable side, so the entire description is omitted. Moreover, the same components as those in the prior art are denoted by the same reference numerals.

  As shown in FIG. 1, an annular first ring plate 20 having a rectangular cross section is coaxially fixed to the disc portion 11 a of the movable-side electric field relaxation shield 11. The outer diameter of the first link plate 20 is smaller than the outer diameter of the movable side sealing fitting 3. An O-ring 13 is provided on the outer periphery of the first ring plate 20, and is compressed between the disc portion 11a and the end of the movable side sealing fitting 3. The height of the first ring plate 20 is adjusted so that the O-ring 13 is compressed within a range of 10 to 20% when the upper surface in the drawing abuts against the movable side sealing fitting 3. The inner diameter is larger than the outer diameter of the movable energizing shaft 7.

  An insulating layer 14 is provided on the outer periphery of the vacuum insulating container 1 as in the prior art, and a ground layer 15 is provided on the outer periphery thereof. A resin intrusion prevention pipe 12 is provided on the inner periphery of the disc portion 11a so as to surround the movable side energizing shaft 7.

  At the time of molding, the entire circumference of the first ring plate 20 is fixed to the casting mold while being in contact with the movable side sealing fitting 3. That is, the movable-side electric field relaxation shield 11 is pressed against the movable-side sealing metal fitting 3 so that the entire circumference of the O-ring 13 is uniformly compressed. Then, an epoxy resin is injected into the cavity and cured by heating to form the insulating layer 14. Thereby, the parallelism of the disc part 11a and the movable side sealing metal fitting 3 improves, and the cylinder part 11b and the curved part 11c are arrange | positioned coaxially. The insulation thickness from the cylindrical portion 11b to the ground layer 15 and the distance between the vacuum insulating container 1 and the curved portion 11c are uniform over the entire circumference. Further, since the entire circumference of the O-ring 13 is uniformly compressed, it is possible to reliably prevent the resin from entering the movable side energizing shaft 7 side.

In the molding, the vacuum insulating container 1 is roughened by, for example, sandblasting, and a surface modifier such as a silane coupling agent is applied, and the movable-side sealing metal fitting 3 is epoxy-coated after roughening. It is preferable to apply a primer treatment composed of a resin and dimer acid. Furthermore, the epoxy resin uses a combination of bisphenol A type or bisphenol F type, an acid anhydride curing agent and silica particles, and has a thermal expansion coefficient of about 1.8 × 10 ⁻⁵ (1 / K). In terms of stress relaxation, it is preferable to use a copper alloy such as brass having a thermal expansion coefficient comparable to that of the mold resin for the movable-side electric field relaxation shield 11 and the first ring plate 20.

  As a result, the partial discharge start voltage was improved by about 50% in experimental values compared to the conventional case. Further, the stress at the tip of the bending portion 11c increases by about 20% when the analytical value is decentered by 1 mm. The tested vacuum valve has an outer diameter of 150 mm, the insulating layer 14 has an insulating thickness of 35 mm, the distance between the curved portion 11c and the vacuum insulating container 1 is 5 mm, and the height of the first ring plate 20 is 3 mm.

  The fixed-side electric field relaxation shield is fixed to the fixed-side sealing metal fitting or the fixed-side energizing shaft and is arranged on the same axis. However, similarly to the movable side, the O-ring 13 and the first ring plate 20 are used. Can be fixed. For this reason, the O-ring 13 and the first ring plate 20 are used at least on the movable side.

  Further, instead of the O-ring 13, a conductive rubber packing may be used. These are called elastic members. Of course, the elastic member has heat resistance that can withstand the temperature at the time of molding, but if a hollow member is used, the entire circumference can be compressed with a small compression force, and the first ring plate 20 can be compressed. Can be easily brought into contact with the movable-side sealing fitting 3.

  According to the resin-insulated vacuum valve of the first embodiment, the first ring plate 20 is provided on the disc portion 11a of the movable-side electric field relaxation shield 11, and the O-ring is provided until the entire circumference contacts the movable-side sealing fitting 3. Since 13 is compressed, the parallelism of the disc part 11a and the movable side sealing metal fitting 3 improves, and the cylinder part 11b and the curved part 11c can be arrange | positioned on the coaxial of a vacuum valve. And the insulation thickness from the cylinder part 11b to the grounding layer 15, and the space | interval of the vacuum insulation container 1 and the curved part 11c can be made uniform over a perimeter, and an insulation characteristic and an internal stress characteristic can be improved. it can.

  Next, a resin insulated vacuum valve according to Example 2 of the present invention will be described with reference to FIG. FIG. 2 is an enlarged cross-sectional view of the main part showing the configuration of the resin insulated vacuum valve according to the second embodiment of the present invention. The second embodiment differs from the first embodiment in that the curved portion is changed from a U-shaped cross section to a circular cross section. In FIG. 2, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 2, the curved portion 11c of the movable-side electric field relaxation shield 11 is bent until the end portion faces the cylindrical portion 11b, and has a circular cross section. The curved portion 11c may be a round bar and connected to the tube portion 11b.

  According to the resin insulated vacuum valve of the second embodiment, in addition to the effects of the first embodiment, the internal stress of the insulating layer 14 in the vicinity of the curved portion 11c can be reduced.

  Next, a resin insulated vacuum valve according to Example 3 of the present invention will be described with reference to FIG. FIG. 3 is an enlarged cross-sectional view of a main part showing the configuration of a resin insulated vacuum valve according to Example 3 of the present invention. The third embodiment is different from the second embodiment in that a second ring plate is provided in the disc portion. In FIG. 3, the same components as those in the second embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 3, an annular second ring plate 21 is coaxially fixed on the outer periphery of the O-ring 13 in the disc portion 11 a of the movable-side electric field relaxation shield 11. The inner diameter of the second ring plate 21 is slightly larger than the outer diameter of the movable-side sealing metal fitting 3 and the height thereof is higher than that of the first ring plate 20. The distance between the first ring plate 20 and the second ring plate 21 does not hinder the compression of the O-ring 13.

  According to the resin-insulated vacuum valve of the third embodiment, in addition to the effects of the second embodiment, the movable-side electric field relaxation shield 11 can be more reliably attached by fitting the movable-side sealing metal fitting 3 into the second ring plate 21. Can be arranged on the same axis.

  According to the embodiment as described above, the electric field relaxation shields on the fixed side and the movable side can be arranged on the same axis of the vacuum insulating container or the sealing metal fitting. The space | interval with an insulation container can be equalized over a perimeter, and an insulation characteristic can be improved.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Vacuum insulating container 2 Fixed side sealing metal fitting 3 Movable side sealing metal fitting 10 Fixed side electric field relaxation shield 10a, 11a Disc part 10b, 11b Cylindrical part 10c, 11c Bending part 11 Movable electric field relaxation shield 13 O-ring 14 Insulation layer 20 First ring plate 21 Second ring plate

Claims (5)

A vacuum insulating container, a pair of contactable and separable contacts, a vacuum valve having a sealing fitting,
A radially extending disk portion arranged so as to surround the sealing metal fitting, a cylindrical portion connected to the disk portion and extending in the axial direction, and a curved portion connected to the cylindrical portion and bent at the end portion. An electric field relaxation shield configured;
A first ring plate that is fixed to the disk portion and has an entire circumference in contact with the sealing fitting;
An elastic member that is provided on the outer periphery of the first ring plate, and whose entire periphery is compressed by the disk portion and the sealing fitting;
An insulating layer provided on the outer periphery of the vacuum valve;
A grounding layer provided on the outer periphery of the insulating layer,
A resin-insulated vacuum valve, wherein the first ring plate and the elastic member are used at least on the movable side of the vacuum valve.   The resin-insulated vacuum valve according to claim 1, wherein an end portion of the curved portion is bent until it faces the cylindrical portion.   2. The second ring plate having an inner diameter slightly larger than an outer diameter of the sealing metal fitting and having a height higher than that of the first ring plate is provided on the disc portion. The resin insulation vacuum valve according to claim 2.   The resin insulation vacuum according to any one of claims 1 to 3, wherein the electric field relaxation ring and the first ring plate are made of a copper alloy having a thermal expansion coefficient similar to that of a mold resin. valve.   The resin-insulated vacuum valve according to any one of claims 1 to 4, wherein the elastic member is hollow.

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