Solid insulated busbar, gas insulated switchgear, and method for manufacturing solid insulated busbar

Abstract

When a gap occurs between the conductor and the insulating layer, partial discharge occurs in the gap, reducing the withstand voltage performance. Therefore, the present invention aims to provide a solid insulated busbar, a gas-insulated switchgear, and a method for manufacturing a solid insulated busbar that can suppress peeling between the busbar conductor and the insulating layer. The solid insulated busbar according to the present disclosure includes a bus conductor, an insulating layer provided to cover the bus conductor, and a primer that is applied to the surface of the bus conductor before being hardened by heat treatment to form the insulating layer, and that bonds the bus conductor and the insulating layer together by heat treatment.

Description

[Technical Field]

[0001] The present disclosure relates to a solid insulated busbar that electrically connects a plurality of switchgears and a method for manufacturing the solid insulated busbar. [Background technology]

[0002] A gas-insulated switchgear houses the main circuit section to which high voltage is applied in a sealed container, which is filled with SF6 gas or other gas with excellent insulating properties. The excellent insulating properties of SF6 gas allow gas-insulated switchgear to reduce the space required for arc insulation, making it possible to downsize the device. Such gas-insulated switchgear is composed of multiple sections, each containing one or more switches, lined up and connected by busbars called solid-insulated busbars. The most common busbar connection method is the gas busbar method, which connects adjacent busbar tanks and the busbar conductors inside the busbar tanks.

[0003] Patent Document 1 discloses a solid insulated busbar in which a film-like insulating layer is wrapped around a busbar conductor that connects the main circuit units of adjacent switchgears. The insulating layer of this solid insulated busbar is made of a synthetic resin material or the like, and the busbar conductor and the film-like insulating layer are fixed together with an adhesive. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-035625 Summary of the Invention [Problem to be solved by the invention]

[0005] The bus conductor and insulating layer of a solid insulated bus bar expand due to heat generated when current is applied. The expansion of the synthetic resin material in a solid insulated bus bar can cause the bus conductor and insulating layer to separate, creating a gap inside the bar. Therefore, with conventional solid insulated bus bars, partial discharges can occur in the gap when a gap forms between the bus conductor and insulating layer, resulting in a decrease in voltage resistance.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a solid insulated busbar, a gas-insulated switchgear, and a method for manufacturing a solid insulated busbar that can suppress peeling between the busbar conductor and the insulating layer. [Means for solving the problem]

[0009] The method for manufacturing a solid insulated busbar according to the present disclosure includes the steps of applying a primer to a busbar conductor, setting the busbar conductor with the applied primer in a mold, filling the mold with an insulator, performing a first heat treatment to harden the insulator and form an insulating layer, and performing a second heat treatment to heat the busbar conductor, the primer, and the insulator at a temperature higher than that of the first heat treatment. [Effects of the Invention]

[0010] According to the solid insulated bus bar, gas insulated switchgear, and method for manufacturing a solid insulated bus bar disclosed herein, peeling between the bus conductor and the insulating layer can be suppressed by applying a primer to the bus conductor before heat treatment. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view illustrating a structure of a solid insulated bus bar according to a first embodiment of the present disclosure. [Figure 2] 1 is a cross-sectional view illustrating a connection between a solid insulated bus bar and a peripheral component according to a first embodiment of the present disclosure. [Figure 3] 4 is a flowchart showing a method for manufacturing a solid insulated bus bar according to the first embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, a solid insulated bus bar according to the present disclosure will be described with reference to the drawings.

[0013] Embodiment 1 FIG. 1 is a cross-sectional view showing the structure of a solid insulated busbar according to a first embodiment of the present disclosure. A solid insulated busbar 1 according to the present disclosure is used to connect main circuit sections (not shown) of gas-insulated switchgears when a plurality of gas-insulated switchgears are arranged side-by-side on a panel. As shown in FIG. 1, the solid insulated busbar 1 according to the first embodiment of the present disclosure includes a bus conductor 1a, an insulating layer 1b, and a primer 11. The bus conductor 1a is a conductor connected to the main circuit section of the gas-insulated switchgear.

[0014] The insulating layer 1b is provided so as to cover the bus conductor 1a, and is formed by hardening an insulator through heat treatment. The insulator used for the insulating layer 1b may be, for example, silicone rubber, ethylene propylene rubber, or the like.

[0015] As shown in Fig. 1, the primer 11 is applied to the surface of the bus conductor 1a before the insulating layer 1b is hardened by heat treatment, and the primer 11 bonds the bus conductor 1a and the insulating layer 1b together. Even if the insulating layer 1b expands or contracts due to temperature changes after the heat treatment, the primer 11 bonds the bus conductor 1a and the insulating layer 1b together, preventing the bus conductor 1a from peeling off from the insulating layer 1b.

[0016] FIG. 2 is a cross-sectional view showing a connection between a solid insulated bus bar according to the first embodiment of the present disclosure and peripheral components. As shown in FIG. 2, the solid insulated bus bar 1 according to the first embodiment of the present disclosure is connected to an insulating adapter 2, an insulating plug 4, and a bushing 3. The insulating adapter 2 is provided at the end of the solid insulated bus bar 1 of the present disclosure and is an insulator that supports the solid insulated bus bar 1. The insulating adapter 2 is made of a relatively soft and elastic insulator such as silicone rubber or ethylene propylene rubber. The insulating adapter 2 has a conductive layer 2c that reduces the electric field of the live part, an insulating layer 2b that insulates the live part from the outside, and a ground shielding layer 2a that shields the electric field generated by the live part.

[0017] As shown in Figure 2, the insulating adapter 2 has a T-shape with a vertically extending conical section and a horizontally extending cylindrical section that intersects with the conical section. The end of the solid insulated busbar 1 is inserted in the direction of the arrow in Figure 2 and is fixed to the insulating adapter 2 by fastening it to the fixing conductor 6 provided inside the insulating adapter 2 with a stud bolt 5 and a nut 7. The fixing conductor 6 is responsible for the electrical conductivity between the center conductor 3a and the busbar conductor 1a, and is made of a highly conductive metal such as copper or aluminum. During the fastening process, the supporting conductor 8 is positioned so that the fixing conductor 6 and the busbar conductor 1a are in face-to-face contact.

[0018] The insulating plug 4 has a conical portion 4a, which is an insulator, and filler metals 4b and 4c, and the conical portion 4a is connected to the solid insulated bus bar 1 by fixing the filler metal 4c, and the conical portion 4a is connected to the insulating adapter 2 by fixing the filler metal 4b. As shown in FIG. 2, the conical portion 4a is provided inside the insulating adapter 2.

[0019] The bushing 3 has a central conductor 3a and an insulating portion 3b that connect the solid insulated bus 1 and a main circuit portion (not shown) in which a switch is provided, and the central conductor 3a is connected to the solid insulated bus 1, and the insulating portion 3b is connected to the insulating adapter 2. Here, the center of the central conductor 3a refers to the center of the bushing 3 in the cross-sectional view of Fig. 2, and is the location of the central axis of the cone shape as shown in Fig. 2.

[0020] The bushing 3 and the insulating plug 4 may be coated with grease before being inserted into the insulating adapter 2. Furthermore, the bushing 3 and the insulating plug 4 are connected to the insulating adapter 2 while maintaining a constant surface pressure.

[0021] FIG. 3 is a flowchart showing a method for manufacturing a solid insulated bus bar according to the first embodiment of the present disclosure. In FIG. 3, first, in step S1, a primer 11 is applied to a bus conductor 1a. According to the disclosed method for manufacturing a solid insulated bus bar, applying the primer 11 before heat treatment can prevent separation between the bus conductor 1a and the insulating layer 1b. In step S2, the bus conductor 1a coated with the primer 11 is set in a mold. In step S3, the mold is filled with an insulator. This insulator will become the insulating layer 1b in a later process. In step S4, a first heat treatment is performed to harden the insulator. In step S5, a second heat treatment is performed to heat the bus conductor 1a, the primer 11, and the insulator at a temperature higher than that of the first heat treatment. In the method for manufacturing a solid insulated bus bar according to the first embodiment of the present disclosure, the second heat treatment volatilizes and removes low-molecular-weight siloxane from the silicone.

[0022] Therefore, the manufacturing method of the solid insulated busbar according to the present disclosure includes the steps of applying a primer 11 to the busbar conductor 1a, setting the busbar conductor 1a coated with the primer 11 in a mold, filling the mold with an insulator, performing a first heat treatment to harden the insulator, and performing a second heat treatment to heat the busbar conductor 1a, the primer 11, and the insulator at a temperature higher than that of the first heat treatment.

[0023] As described above, the solid insulated bus bar 1 according to the first embodiment of the present disclosure includes a bus conductor 1a including a conductor, an insulating layer 1b that covers the surface of the bus conductor 1a and is formed by hardening the insulator through heat treatment, and a primer 11 that is applied to the surface of the bus conductor 1a before the insulating layer 1b is hardened through heat treatment and that bonds the bus conductor 1a and the insulating layer 1b together through the heat treatment. Therefore, the solid insulated bus bar 1 and the method for manufacturing the solid insulated bus bar according to the first embodiment of the present disclosure can suppress peeling between the bus conductor 1a and the insulating layer 1b by applying the primer 11 before the heat treatment.

[0024] Furthermore, in the solid insulated busbar 1 of the present disclosure, the busbar conductors that connect the insulating adapters are covered with an insulating layer 1b made of rubber (silicone or EPDM), resin (epoxy material), or the like. Because the solid insulated busbar is an interface-connected component, it is preferable that it does not have a parting line (PL: the line between the divided molds). If a resin such as epoxy is used for the insulating layer, a parting line is often required due to the mold structure. If a parting line exists, burrs will form on the line after heat treatment, which requires work to remove them. Furthermore, if the burrs are not completely removed, the voltage resistance performance of the solid insulated busbar may be reduced.

[0025] Furthermore, the insulating layer 1b of the solid insulated bus bar 1 of the present disclosure is made of rubber, which can mitigate the thermal stress fluctuations that occur at the interface (bonding portion) due to differences in the thermal expansion coefficients of the bus bar conductor 1a and the insulating layer 1b caused by temperature changes. With this configuration, the solid insulated bus bar 1 of the present disclosure can more effectively prevent separation between the bus bar conductor 1a and the insulating layer 1b.

[0026] The solid insulated bus bar 1 of the present disclosure uses rubber for the insulating layer 1b, which allows for molding of the insulating layer 1b without PL by taking advantage of the difference in thermal expansion coefficient between the mold and rubber. This prevents burrs from forming, which is expected to improve work efficiency.

[0027] Furthermore, if a resin such as an epoxy material is used for the insulating layer 1b, the epoxy material has a thermal expansion coefficient similar to that of the metal mold, so the epoxy resin does not shrink significantly when released from the cylindrical mold after cooling, making release difficult. This necessitates a process of tapering the mold or dividing the mold into two parts when manufacturing the solid insulated bus bar 1. The solid insulated bus bar 1 of the present disclosure uses rubber for the insulating layer 1b, which has a higher thermal expansion coefficient than the mold. The solid insulated bus bar 1 of the present disclosure has the advantage that the insulating layer 1b shrinks more than the mold after cooling, making it easier to release from the mold.

[0028] In the solid insulated bus bar 1 of the present disclosure, the material of the primer 11 may contain at least one of a silicone and an epoxy material. By using a silicone and an epoxy material, the solid insulated bus bar of the present disclosure can withstand the second heat treatment (e.g., about 200°C) which is higher than the first heat treatment (e.g., about 90 to 120°C) during molding of the insulating layer 1b, thereby more effectively preventing peeling between the bus conductor 1a and the insulating layer 1b.

[0029] In the solid insulated bus bar 1 of the present disclosure, the primer 11 may be made of an elastic material. In this case, the primer 11 may be made of, for example, silicone, a resin material, or a mixture of silicone and epoxy material. This configuration allows the primer 11 to withstand changes in stress due to temperature changes, thereby more effectively preventing separation between the bus bar conductor 1a and the insulating layer 1b.

[0030] The solid insulated busbar 1 of the present disclosure is used in a gas-insulated switchgear. The gas-insulated switchgear is a power receiving and distribution facility that houses switches and other devices that turn on and off a main circuit section. This switchgear includes an insulating adapter 2 that is provided at the end of the solid insulated busbar 1, 12 and serves as an insulator supporting the solid insulated busbar 1, 12, an insulating plug 4 that has a conical portion 4a and filler metals 4b, 4c that are also insulators, and that connects the conical portion 4a to the solid insulated busbar and the insulating adapter 2 by fixing the filler metals 4b, 4c, and a bushing 3 that has a center conductor 3a and an insulating portion 3b that connects the solid insulated busbar to a main circuit section in which a switch is provided, and that connects the center conductor 3a to the solid insulated busbar and the insulating portion 3b to the insulating adapter 2.

[0031] The configurations described in the above embodiments are merely examples of the contents of the present disclosure, and may be combined with other known technologies. Furthermore, parts of the configurations may be omitted or modified without departing from the scope of the present disclosure.

[0032] Various aspects of the present disclosure are summarized below as appendices. (Appendix 1) a bus conductor; an insulating layer provided to cover the bus conductor; a primer that is applied to the surface of the bus conductor before the insulating layer is formed by being hardened by heat treatment, and that bonds the bus conductor and the insulating layer together by heat treatment. (Appendix 2) 2. The solid insulated bus bar according to claim 1, wherein the insulating layer is made of rubber, and when thermal stress changes due to a difference in the thermal expansion coefficients of the bus bar conductor and the insulating layer caused by a temperature change, the rubber relieves the stress. (Appendix 3) 3. The solid insulated bus bar according to claim 1, wherein the primer material includes at least one of a silicone material and an epoxy material. (Appendix 4) 4. The solid insulated bus bar of claim 1, wherein the primer material includes an elastic material. (Appendix 5) a solid insulated busbar according to any one of appendices 1 to 4; an insulating adapter, which is the insulator provided at an end of the solid insulated bus bar and supports the solid insulated bus bar; an insulating plug having a conical portion as the insulator and a filler metal, the conical portion being connected to the solid insulated bus bar and the insulating adapter by fixing the filler metal; The gas-insulated switchgear includes a central conductor and an insulating part that connect the solid insulated busbar and a main circuit part provided with a switchgear, and includes a bushing to which the central conductor and the solid insulated busbar are connected and to which the insulating part and the insulating adapter are connected. (Appendix 6) applying a primer to the busbar conductor; setting the busbar conductor coated with the primer in a mold; filling the mold with an insulator; a first heat treatment to harden the insulator and form an insulating layer; and performing a second heat treatment, heating the bus conductor, the primer, and the insulator at a temperature higher than that of the first heat treatment. [Explanation of symbols]

[0033] 1 12 solid insulated busbar, 1a busbar conductor, 1b insulating layer, 2 insulating adapter, 2a earthing shield layer, 2b insulating layer, 2c conductive layer, 3 bushing, 3a center conductor, 3b insulating part, 4 insulating plug, 4a cone part, 4b 4c filler metal, 4d metal plate, 4e bolt, 5 stud bolt, 6 fixing conductor, 7 nut, 8 supporting conductor, 9 earthing wire, 10 conductive cap, 11 primer

Claims

1. applying a primer to the busbar conductor; setting the busbar conductor coated with the primer in a mold; filling the mold with an insulator; a first heat treatment to harden the insulator and form an insulating layer; and performing a second heat treatment, heating the bus conductor, the primer, and the insulator at a temperature higher than that of the first heat treatment.

2. 2. The method for manufacturing a solid insulated bus bar according to claim 1, wherein the insulating layer is made of rubber, and when thermal stress changes due to a difference in the thermal expansion coefficients of the bus bar conductor and the insulating layer caused by a temperature change, the rubber relieves the thermal stress.

3. 3. The method for manufacturing a solid insulated bus bar according to claim 1, wherein the material of the primer includes at least one of a silicone material and an epoxy material.

4. 3. The method for manufacturing a solid insulated bus bar according to claim 1, wherein the primer material includes an elastic material.

Images