Solid-insulated bus, gas-insulated switchgear, and method for manufacturing solid-insulated bus

Abstract

When a gap forms between a conductor and an insulating layer, a partial discharge occurs in the gap and voltage withstand performance is degraded, and thus the purpose of the present invention is to provide a solid-insulated bus, a gas-insulated switchgear, and a method for manufacturing a solid-insulated bus, with which it is possible to suppress peeling of a bus conductor and an insulating layer. A solid-insulated bus according to the present disclosure comprises: 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 the insulating layer is formed by being cured by heat treatment, and that fixes the bus conductor and the insulating layer through heat treatment.

Description

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

[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.

[0002] A gas-insulated switchgear houses the main circuit section to which high voltage is applied in a sealed container filled with SF6 gas or other gas with excellent insulating properties. The excellent insulating properties of SF6 gas allow the gas-insulated switchgear to reduce the space required for arc insulation, thereby enabling the device to be miniaturized. Such a gas-insulated switchgear is configured by arranging multiple sections, each containing one or more switches, and connecting them with busbars called solid-insulated busbars. The busbar connection method is generally a gas busbar method, in which adjacent busbar tanks are connected to 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 circuits 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.

[0004] Japanese Patent Application Laid-Open No. 2008-035625

[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.

[0007] 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.

[0008] The gas-insulated switchgear according to the present disclosure includes a solid insulated bus bar, an insulating adapter that is an insulator provided at the end of the solid insulated bus bar and supports the solid insulated bus bar, an insulating plug that has a conical portion that is an insulator and a filler metal, and the conical portion is connected to the solid insulated bus bar and the insulating adapter by fixing the filler metal, and a bushing that has a center conductor and an insulating portion that connects the solid insulated bus bar and a main circuit section in which a switchgear is provided, and that connects the center conductor to the solid insulated bus bar and the insulating portion to the insulating adapter.

[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.

[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.

[0011] 1 is a cross-sectional view illustrating a structure of a solid insulated bus bar according to a first embodiment of the present disclosure, a cross-sectional view illustrating a connection between the solid insulated bus bar according to the first embodiment of the present disclosure and a peripheral component, and a flowchart illustrating a method for manufacturing the solid insulated bus bar according to the first embodiment of the present disclosure.

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

[0013] First Embodiment. Figure 1 is a cross-sectional view showing the structure of a solid insulated busbar according to a first embodiment of the present disclosure. The 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 Figure 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] Figure 2 is a cross-sectional view showing the connection between a solid insulated bus bar and peripheral components according to the first embodiment of the present disclosure. As shown in Figure 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 an insulator provided at the end of the solid insulated bus bar 1 of the present disclosure and supports the solid insulated bus bar 1. The insulating adapter 2 is made of a relatively soft and elastic insulating material 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 portion and a horizontally extending cylindrical portion that intersects the conical portion. 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 a 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 operation, 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. 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 the bus conductor 1a. According to the disclosed method for manufacturing a solid insulated bus bar, applying the primer 11 before heat treatment can prevent peeling 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 bus bar according to the present disclosure includes the steps of applying a primer 11 to the bus bar conductor 1 a, setting the bus bar conductor 1 a 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 bus bar conductor 1 a, 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 1 a including a conductor, an insulating layer 1 b formed by covering the surface of the bus conductor 1 a and hardening the insulator by heat treatment, and a primer 11 applied to the surface of the bus conductor 1 a before the insulating layer 1 b is hardened by heat treatment to bond the bus conductor 1 a and the insulating layer 1 b together by 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 1 a and the insulating layer 1 b by applying the primer 11 before the heat treatment.

[0024] Furthermore, in the solid insulated busbar 1 of the present disclosure, the busbar conductors connecting 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 connection component, it is preferable that there be no parting line (PL: the line between the divided molds). If a resin such as epoxy is used for the insulating layer, PL is almost always required due to the mold structure. If PL is present, 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 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 further prevent peeling between the bus 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 the 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 mold (metal), 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, such as 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 conductor 1 a and the insulating layer 1 b.

[0030] The solid insulated bus 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. The switchgear includes an insulating adapter 2 that is provided at the end of the solid insulated bus 1, 12 and serves as an insulator supporting the solid insulated bus 1, 12, an insulating plug 4 that has a conical portion 4a and filler metals 4b and 4c that are also insulators, and that connects the conical portion 4a to the solid insulated bus and the insulating adapter 2 by fixing the filler metals 4b and 4c, and a bushing 3 that has a center conductor 3a and an insulating portion 3b that connects the solid insulated bus and a main circuit section in which a switch is provided, and that connects the center conductor 3a to the solid insulated bus 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 solid insulated busbar comprising: a bus conductor; an insulating layer covering the bus conductor; and a primer applied to the surface of the bus conductor before the insulating layer is hardened by heat treatment to form the primer, thereby bonding the bus conductor and the insulating layer together. (Appendix 2) The solid insulated busbar according to Appendix 1, wherein the insulating layer is made of rubber, and the rubber relieves thermal stress when the thermal stress changes due to a difference in the thermal expansion coefficients of the bus conductor and the insulating layer caused by a temperature change. (Appendix 3) The solid insulated busbar according to Appendix 1 or 2, wherein the primer is made of a material containing at least one of a silicone and an epoxy material. (Appendix 4) The solid insulated busbar according to any one of Appendixes 1 to 3, wherein the primer is made of a material containing an elastic material. (Supplementary Note 5) A gas-insulated switchgear comprising: a solid insulated busbar according to any one of Supplementary Notes 1 to 4; an insulating adapter serving as the insulator provided at an end of the solid insulated busbar and supporting the solid insulated busbar; an insulating plug having a conical portion serving as the insulator and a filler metal, the filler metal being fixed to connect the conical portion to the solid insulated busbar and the insulating adapter; and a bushing having an insulating portion and a center conductor connecting the solid insulated busbar to a main circuit section provided with a switchgear, the bushing connecting the center conductor to the solid insulated busbar and the insulating portion to the insulating adapter. (Supplementary Note 6) A method for manufacturing a solid insulated busbar, comprising the steps of: applying a primer to a bus conductor; setting the bus conductor coated with the 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 bus conductor, the primer, and the insulator at a temperature higher than that of the first heat treatment.

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

Claims

1. A solid insulated busbar comprising: a busbar conductor; an insulating layer provided to cover the busbar conductor; and a primer that is applied to the surface of the busbar conductor before the insulating layer is formed by being hardened by heat treatment, and that bonds the busbar conductor and the insulating layer together by heat treatment.

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.

3. The solid insulated bus bar according to claim 1 or 2, wherein the primer material includes at least one of silicone and epoxy material.

4. The solid insulated bus bar according to claim 1 or 2, wherein the primer material includes an elastic material.

5. A gas-insulated switchgear comprising: a solid insulated busbar according to claim 1 or 2; an insulating adapter, which is the insulator provided at the end of the solid insulated busbar and supports the solid insulated busbar; an insulating plug, which has a conical portion, which is the insulator, and a filler metal, and which connects the conical portion to the solid insulated busbar and the insulating adapter by fixing the filler metal; and a bushing, which has a center conductor and an insulating portion, which connects the solid insulated busbar to a main circuit portion in which a switchgear is provided, and which connects the center conductor to the solid insulated busbar and the insulating portion to the insulating adapter.

6. A method for manufacturing a solid insulated busbar, comprising the steps of: applying a primer to a busbar conductor; setting the busbar conductor coated with the 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.

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