A method and device for flexible connection of insulated tube bus to combined electrical apparatus GIS

Abstract

The application discloses a method and device for realizing flexible connection of an insulated tube bus and a combined electric appliance GIS. The technical key points are as follows: a high-voltage cable is used to form a system for realizing flexible connection of the insulated tube bus and the combined electric appliance GIS. The system comprises an insulated tube bus, a conversion joint of the insulated tube bus and the cable, a cable, a cable GIS terminal and a combined electric appliance GIS input end. The application has the advantages that the cable has better bending property than the insulated tube bus, and the rigid connection of the insulated tube bus and the GIS system is converted into the flexible connection of the cable and the combined electric appliance GIS input end through the conversion joint. The connection method and device can overcome the defects of the existing 110kV insulated tube bus and the combined electric appliance GIS connection, such as rigidity and poor installation effect, and can realize the connection of the insulated tube bus and the combined electric appliance GIS input end conveniently according to the site conditions by changing the cable length and arrangement mode without adjusting the position and laying mode of the insulated tube bus. All the connections realize electrical connection, insulation recovery and shielding continuity, and the reliability of the system is improved and the engineering cost is reduced.

Description

Technical Field

[0001] This invention relates to the technical field of electrical connection between insulated busbars and GIS (Gas Switchgear) in power transmission and transformation systems. Background Technology

[0002] Currently, the direct connection between high-voltage insulated busbars (specifically referring to those with shielding structures, also known as insulated shielded busbars) and GIS (Gas-Insulated System) presents the following problems: Firstly, existing insulated busbars face difficulties in matching specifications with the input terminals of GIS systems, and there is a lack of industrially standardized GIS terminals for the busbars. Secondly, the high rigidity of insulated busbars, due to thermal expansion and contraction, can easily lead to gaps caused by excessive or insufficient stress during direct connection to the GIS system, resulting in poor sealing at the connection point. Thirdly, the axes of the insulated busbars and the GIS system input terminals are perpendicular, requiring a conversion from a horizontal to a vertical configuration. Existing technologies are insufficient and do not meet the requirements for flexible connection between insulated busbars and GIS systems.

[0003] Patent CN203026716U discloses a busbar-shielded insulated GIS terminal connector, which essentially involves manufacturing a connector with an insulating shield at the end of a rigid insulated busbar: the left side of the connector is made into a GIS insertion end, which can be directly connected to the input end of a combined electrical appliance (GE) GIS; the right side of the connector is the insulated busbar. This implementation still represents a rigid connection between the insulated busbar and the GE GIS, and the busbar requires a horizontal-to-vertical conversion, failing to achieve a flexible connection or convenient direction conversion. Other technical details also differ significantly from this invention. Patent CN203151019U is related to patent CN203026716U. CN203151019U is a utility model, primarily focusing on a GIS sleeve-shaped end formed by casting insulating resin material for one side of the busbar-shielded insulated GIS terminal connector described in CN203026716U, which is connected to the GE GIS of a combined electrical appliance.

[0004] Patent CN207518173U discloses a horizontal conduit cable terminal connection device for GIS (Gas Insulated Switchgear). Its technical essence is to ensure the cable is horizontally connected to the GIS, which is a connection between the cable and the GIS, not between the insulated busbar and the GIS, thus differing from the focus of this invention. Implementation of CN207518173U requires on-site rotation of the GIS input end from a vertical to a horizontal cable entry method. This necessitates technical modifications to the GIS enclosure, potentially causing changes to the internal conductive structure and the connection structure of the casing, posing a risk to the GIS's sealing. Furthermore, it requires the installation of support frames under the rotating enclosure. The rotating enclosure and cable connection device will have significant weight, leading to changes in the enclosure's center height and other deformations over time, potentially causing SF6 insulation gas leakage at the enclosure connection points.

[0005] Patent CN103944123A discloses a capacitive insulated busbar system for fully shielded connection with high-voltage cables. Its core technology involves inventing a connector for connecting the insulated shielded tube busbar to the high-voltage cable, which overlaps with the purpose of this invention. This invention utilizes an insulated shielded tube, within which the insulated busbar and cable are connected. The conductor connection employs a common contact method with conductive tubes, requiring fixed flange ends on both sides, which are sealed to the busbar and cable respectively. This implementation requires strict control of installation dimensions, has potential safety hazards in the conductor connection, and the insulation of the connector relies solely on the insufficient margin of the intermediate resin layer of the insulated shielded tube. The seals on both sides of the flanges are susceptible to moisture absorption. Furthermore, the connector is generally long, installation is complex, and the manufacturing process of the insulated shielded tube is complex and costly. Other technical details also differ significantly from this invention. Summary of the Invention

[0006] The purpose of this invention is to provide a method and apparatus for achieving flexible connection between insulated busbars and GIS (Gas Switchgear Integrated System) to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides and implements the following technical solution: a method and apparatus for flexibly connecting an insulated busbar (hereinafter referred to as the busbar) to a GIS (Gas Switchgear Integrated System), thereby optimizing the connection between the busbar and the GIS system. The method and apparatus include a busbar, a conversion joint between the busbar and a cable, a cable, a cable GIS terminal, and an input terminal of the GIS system. Specifically, the busbar and the cable are connected via the conversion joint; the cable is connected to the GIS input terminal via the cable GIS terminal.

[0008] The aforementioned busbar is an insulated and shielded busbar. Its structure and materials, from the inside out, consist of a conductive copper tube (hereinafter referred to as copper tube), an insulation layer, an insulation shielding layer, a copper shielding layer, and a sheath layer. The conductor is a copper tube, the insulation layer is made of cast epoxy resin with a capacitor shield structure, the insulation shielding layer is made by wrapping semi-conductive tape, the copper shielding layer is wrapped copper tape, and the sheath layer is a material layer with sealing, moisture-proof, and corrosion-proof functions formed by heat-shrinkable sheath tubing through a heat shrinking process.

[0009] The cable, from the inside out, consists of a conductor core, an insulation layer, an outer shielding layer, a corrugated aluminum sheath, and a PVC sheath. The conductor core is a copper conductor (hereinafter referred to as the conductor), the insulation layer is cross-linked polyethylene, the outer shielding layer is a semi-conductive material layer, the corrugated aluminum sheath provides grounding current conduction and mechanical protection, and the PVC sheath is the outermost structural layer of the cable, serving to seal, prevent moisture, and prevent corrosion.

[0010] The busbar and cable conversion joint (hereinafter referred to as the conversion joint) consists of functional layers and corresponding materials, from the inside out: conductor connection assembly, heat-shrink film insulation layer, shielding layer, copper braided mesh layer, copper braided ground wire, insulating resin layer, and joint protective shell. The functions of each layer are as follows:

[0011] The conductor connection assembly consists of a copper tube of a busbar, conductor connection fittings, and a cable conductor connected in sequence. The copper tube and conductor connection fittings are connected by welding, and the conductor connection fittings and conductors are connected by crimping. The conductor connection fittings are separately machined tubular structures, with one side having an outer diameter slightly smaller than that of the busbar copper tube and the other side having an inner diameter slightly larger than that of the cable conductor.

[0012] The heat-shrinkable film insulation layer is the main insulator of the integrated structure of the adapter, formed by heating and shrinking a wrapped heat-shrinkable film. The thickness, length, and slope of the wrapping of the adapter are in accordance with the requirements for connector insulation.

[0013] The shielding layer is formed by wrapping a semiconductive strip around a heat-shrinkable film insulation layer. This connects the shielding layer of the connecting busbar and the outer semiconductive layer of the cable, restoring the shielding of the joint.

[0014] The aforementioned copper braided mesh layer is a metal shielding layer formed by wrapping copper wire braided mesh around the outer layer to create a joint. It connects the cylindrical shielding layer of the busbar and the copper shielding layer of the cable. It restores the metal shielding of the joint.

[0015] The copper braided ground wire is a section of copper braided ground wire used as a connection between the metal shielding layer of the busbar and the corrugated aluminum sheath of the cable.

[0016] The insulating resin layer is a resin insulating material that needs to be poured before the joint is completed. Its purpose is to seal, waterproof, and strengthen the conversion joint.

[0017] The aforementioned connector protective housing is composed of two half-box-shaped housings that are fastened together. After being fastened and secured, the housing is filled with the aforementioned insulating resin to form overall protection for the connector.

[0018] The aforementioned cable GIS terminal is an industrialized cable terminal assembly installed at the end of the continuation cable after the conversion joint, enabling effective connection to the input end of a GIS system and facilitating the connection between the cable and the GIS system. Its main components include: a grounding assembly, a stress cone support assembly, a flange (including fixing bolts), an epoxy assembly, and a conductor connector. The installation of the components of the grounding assembly enables grounding of the cable GIS terminal. The stress cone support assembly includes a stress cone for controlling the electric field stress of the cable GIS terminal, a bracket for pressing the stress cone, and a set of bolts for fixing the bracket. The flange (including fixing bolts) secures the entire cable GIS terminal to the GIS input end. The epoxy assembly, installed at the cable end, secures and wraps the front end and outer surface of the stress cone, fixing the stress cone to a designated position on the cable. The conductor connector is installed and fixed on the conductor at the cable end, with its outer surface connected to the inner surface of the GIS conductor.

[0019] The main structure of the combined electrical appliance GIS system input terminal includes: a metal shell, a concave epoxy assembly for the GIS input terminal, SF6 insulating gas, a supporting insulator, and a conductive copper tube. The metal shell, part of the GIS system's metal shell, serves to seal the insulating gas. The lower end of the concave epoxy assembly for the GIS input terminal has bolt holes for accepting the insertion and installation of the cable GIS terminal. The SF6 insulating gas, the main insulating medium of the GIS system, provides primary insulation. The supporting insulator supports the conductive copper tube of the GIS system. The conductive copper tube is a key component for conducting current in the GIS system and needs to be connected to the conductor connector of the cable GIS terminal.

[0020] The connection between the cable and the input terminal of the combined electrical appliance GIS system is achieved through the installation process of inserting the cable GIS terminal into the input terminal of the combined electrical appliance GIS system. The cable end is installed as the cable GIS terminal described in

[0018] , and the cable GIS terminal is fixed to the concave epoxy assembly of the GIS input terminal using the flange and fixing bolts described in

[0018] , thus realizing the connection between the cable and the GIS. Ultimately, the connection between the busbar and the GIS is transformed into a connection between the cable and the GIS.

[0021] The present invention has the following beneficial effects:

[0022] 1. An adapter joint can convert a busbar into a cable, and the connection between the busbar and the GIS (Gas Insulation System) can be transformed into a cable connection. Simultaneously, this joint also converts the rigidity of the busbar into the flexibility of the cable, achieving a flexible connection between the cable and the GIS. The structure and materials used in this adapter joint realize the functions of an electrical connector: electrical connection of the conductors of the busbar and the cable, restoration of insulation and shielding, and connection of the grounding system. This connector also features integrated insulation materials, no need for prefabricated insulation components, low material cost, good electrical stress control, robust structure, and simple installation.

[0023] 2. The cable-GIS connection of this invention is accomplished through the insertion installation of the cable-GIS terminal, realizing the invention's objective of transforming the connection between the busbar and the GIS into a cable-GIS connection. This leverages the electric field stress control advantages of the cable-GIS terminal, improving the electrical reliability of the system, while standardizing the installation process and further reducing installation costs.

[0024] 3. The conductor connection in the conversion connector of the present invention adopts a transition connection method using conductor connection hardware, which improves the electrical current conduction capacity of the conversion connector, increases the electric field uniformity, and thus improves the reliability of the electrical connection of the conversion connector.

[0025] 4. The adapter of the present invention uses heat-shrinkable insulating film to insulate the adapter, and then wraps semi-conductive tape around the insulating adapter to complete the shielding of the adapter. This is beneficial to the integrated insulation and shielding structure of the adapter, with no interlayer gaps, and improves the electrical insulation reliability of the adapter.

[0026] 5. This invention utilizes the flexibility of cables to adapt to the arrangement and adjustment of the deflection angle of busbars, making installation unrestricted by site conditions. By converting between busbars and cables, the initial calibration of the busbar installation position is eliminated, and the problem of matching copper pipe specifications with GIS is solved. This method improves work efficiency and product reliability. Furthermore, the device is easy to assemble and disassemble, facilitating daily maintenance, testing, and repair of the busbars and GIS. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the device used by the present invention to realize the flexible connection between the busbar and the GIS; Figure 2 This is a schematic diagram of the conversion joint structure for connecting the busbar and the cable, a schematic diagram of the protective housing, a cross-sectional view of the conductor connection hardware, and a schematic diagram of the epoxy assembly outline of the present invention.

[0028] Figure 1In the diagram, 1-1-Busbar, 1-2-Converter joint between busbar and cable, 1-3-Cable, 1-4-Cable GIS terminal, 1-5-Input terminal of combined electrical appliance GIS system, 1-4-1-Grounding assembly, 1-4-2-Stress cone support assembly, 1-4-3-Epoxy assembly, 1-4-4-Flange (including fixing bolts), 1-4-5-Conductor connector, 1-5-1-GIS metal housing, 1-5-2-Concave epoxy assembly of GIS input terminal, 1-5-3-Insulating gas, 1-5-4-Supporting insulator, 1-5-5-Conductive copper pipe. The protective housing for the 1-2 converter joint specifically includes: 1-2-1-Connector protective housing, 1-2-2-Fasting bolts, 1-2-3-Cap.

[0029] Figure 2 The specific structure includes: 2-1-Busbar sheath, 2-2-Wrapped copper tape, 2-3-Shielding layer, 2-4-Epoxy resin insulation layer (with capacitor screen), 2-5-Conductive copper tube, 2-6-Conductor connecting hardware, 2-7-Copper core conductor, 2-8-Cable insulation layer, 2-9-Cable outer shielding layer, 2-10-Corrugated aluminum sheath, 2-11-PVC sheath, 2-12-Insulating heat shrink film, 2-13-Joint outer shielding layer, 2-14-Copper braided mesh, 2-15-Copper braided ground wire, 2-16-Insulating potting compound, 1-2-1-Joint protective shell, 2-6-1-Welding area, 2-6-2-Cross-sectional view of conductor connecting hardware, 1-4-3 Epoxy assembly (outline drawing). Detailed Implementation

[0030] The technical solutions in the embodiments of this patent will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described implementation is only a part of the embodiments of this invention, and not all of them, and is not intended to limit the invention.

[0031] To achieve the objectives of this invention, please refer to... Figures 1-2 This invention provides a method and apparatus for achieving flexible connection between an insulated busbar and a GIS (Gas-Insulated Switchgear) system, thereby optimizing the connection between the busbar and the GIS system. The apparatus includes a busbar 1-1, a conversion joint 1-2 for the busbar and cable, a cable 1-3, a cable GIS terminal 1-4, and a GIS system input terminal 1-5. Specifically, the busbar 1-2 and cable 1-3 are connected via the conversion joint 1-2; the cable 1-3 is connected to the GIS system input terminal 1-5 via the cable GIS terminal 1-4.

[0032] The structure and materials of the busbar 1-1, from the outside to the inside, are: busbar sheath 2-1, wrapped copper strip 2-2, shielding layer 2-3, epoxy resin insulation layer (with capacitor screen) 2-4, and conductive copper tube 2-5.

[0033] The cable 1-3 has the following structure and materials from the inside out: copper core conductor 2-7, cable insulation layer 2-8, cable outer shielding layer 2-9, corrugated aluminum sheath 2-10, and PVC sheath 2-11.

[0034] The copper core conductor 2-7 is a cable conductor formed by twisting copper wire, which plays the role of conducting current; the cable insulation layer 2-8 is cross-linked polyethylene, which plays the role of the main insulation of the cable; the cable outer shielding layer 2-9 is composed of the cable extruded semi-conductive layer and copper wire, which plays the role of shielding the cable insulation layer; the corrugated aluminum sheath 2-10 undertakes the functions of grounding current conduction and cable mechanical protection; the PVC sheath 2-11 is the outermost structural layer of the cable, which plays the functions of sealing, moisture-proofing and corrosion protection.

[0035] The conversion joint 1-2 between the busbar and the cable has an internal conductor connecting fitting 2-6-2 that is welded to a conductive copper tube 2-5 and crimped to a copper core conductor 2-7, together forming a conductor connection assembly. The external structure of the conductor connection assembly consists of, in sequence, a heat-shrinkable film insulation layer, a shielding layer, a copper braided mesh layer, a copper braided ground wire, an insulating resin layer, and a joint protective shell. The conductor connection assembly and the external layers together form the conversion joint connecting the busbar 1-1 and the cable 1-3.

[0036] The copper core conductor 2-7 of the cable 1-3 is connected to the conductive copper tube 2-5 through the conductor connecting hardware 2-6.

[0037] The cable terminal 1-4, from top to bottom, consists of a conductor connector 1-4-5, an epoxy assembly 1-4-3, a flange (including fixing bolts) 1-4-4, a stress cone drag assembly 1-4-2, and a grounding assembly 1-4-1. The end conductor of the lower cable 1-3 is fixedly connected to the conductor connector 1-4-5 to achieve a fixed connection between the cable and the cable terminal. The outer side of the conductor connector is inserted into the inner side of the GIS conductor to complete the connection, and the flange is used to fix the cable terminal and the GIS input end.

[0038] The input terminal 1-5 of the combined electrical appliance GIS system and the cable GIS terminal 1-4 are fixedly connected by flange 1-4-4.

[0039] In use, the specific operation is as follows: weld the conductive copper tube 2-5 to the conductor connecting hardware 2-6, and then crimp the copper core conductor 2-7 to the conductor connecting hardware 2-6. The three together form the conductor connection assembly. The conductor connection assembly is externally constructed by sequentially using an insulating heat-shrinkable film 2-12, a connector outer shielding layer 2-13 made of semi-conductive tape, a copper braided mesh 2-14 made of copper wire, a section of copper braided ground wire 2-15 connecting the busbar and the corrugated aluminum sheath of the cable, and the outermost connector protective shell 1-2-1. The two semi-box-shaped shells are fastened together with bolts. After potting with insulating potting compound 2-16, the overall protection and connection of the busbar → conversion joint → cable is completed. Next, the conductor at the other end of the cable is welded to the conductor connector 1-4-5 and then passed through the grounding assembly 1-4-1, stress cone bracket assembly 1-4-2, and epoxy assembly 1-4-3 sequentially from bottom to top. Then, the epoxy assembly 1-4-3, stress cone bracket assembly 1-4-2, and grounding assembly 1-4-1 are secured with bolts in sequence, thus achieving a fixed connection between cable 1-3 and cable GIS terminal 1-4. Finally, the conductor connector 1-4-5 of the cable GIS terminal is inserted into the conductive copper tube 1-5-5 of the combined electrical appliance GIS input terminal 1-5 until the epoxy assembly 1-4-3 of the cable GIS terminal contacts the concave epoxy assembly 1-5-2 of the combined electrical appliance GIS input terminal. The fixed connection between the cable GIS terminal and the combined electrical appliance GIS input terminal is achieved using bolts and flange 1-4-4. The distance between the busbar 1-1 and the combined electrical appliance GIS input terminal 1-5 is adjusted by selecting an appropriate cable length 1-3 to facilitate installation and maintenance and reduce work time.

[0040] Those skilled in the art should understand that variations can be implemented by combining existing technology with the above embodiments, which will not be elaborated here. Such variations do not affect the essence of the present invention, and will not be elaborated here either.

[0041] The preferred embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and the devices and structures not described in detail should be understood as being implemented in a conventional manner in the art. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the scope of the present invention, using the methods and content disclosed above. This does not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for achieving flexible connection between insulated busbars and GIS (Gas Switchgear Integrated Circuit), characterized in that: A system is formed using a high-voltage cable to achieve flexible connection between an insulated busbar and a GIS (Gas Insulated Switchgear) system. The system includes an insulated busbar, a conversion joint between the insulated busbar and the cable, a cable, a cable GIS terminal, and a GIS input terminal for the GIS. Specifically, the insulated busbar and the cable are connected through the conversion joint; the cable and the GIS input terminal of the GIS are connected through the cable GIS terminal. The insulated busbar is an insulated and shielded busbar. Its structure and materials, from the inside out, consist of a conductive copper tube, an insulating layer, an insulating shielding layer, a copper shielding layer, and a sheath layer. The cable has a structure consisting of, from the inside out, a conductor core, an insulation layer, an outer shielding layer, a corrugated aluminum sheath, and a PVC sheath, wherein the conductor core is a copper conductor. The conversion joint between the insulated busbar and the cable consists of, from the inside out: conductor connection assembly, heat-shrinkable insulation layer, shielding layer, copper braided mesh layer, copper braided ground wire, insulating resin layer, and joint protective shell; The conductor connection assembly is composed of an insulated busbar conductive copper tube, conductor connection hardware, and cable core conductor connected in sequence. The copper tube and conductor connection hardware are connected by welding, and the conductor connection hardware and cable core conductor are connected by crimping. The conductor connection hardware is a separately processed tubular structure with an outer diameter on one side slightly smaller than that of the busbar copper tube and an inner diameter on the other side slightly larger than that of the cable core conductor. The heat-shrinkable film insulation layer is formed by wrapping heat-shrinkable film and then heating and shrinking it. The shielding layer is made by wrapping a semi-conductive tape around a heat-shrinkable insulating layer; The copper braided mesh layer is a metal shielding layer formed by wrapping copper wire braided mesh tape around the outside of the shielding layer to form a joint; A copper braided ground wire is a section of copper braided ground wire used to connect the copper shielding layer of the conduit busbar and the corrugated aluminum sheath of the cable. The insulating resin layer is a resin-based insulating material poured before the joint is completed. The connector protective housing is composed of two half-box-shaped housings that are fastened together. After being fastened and secured, the aforementioned insulating resin is applied to form an overall protective layer for the connector.

2. The method for achieving flexible connection between insulated busbars and GIS (Gas Switchgear) according to claim 1, characterized in that: The method flow is as follows: busbar preparation → cable preparation → adapter connection → cable preparation → cable GIS preparation → cable GIS terminal preparation → combined electrical equipment GIS input terminal preparation → connection between cable GIS terminal and combined electrical equipment GIS input terminal.

3. The method for achieving flexible connection between insulated busbars and GIS (Gas Switchgear Integrated Circuit) as described in claim 1, characterized in that: The connection between the cable GIS terminal and the combined electrical GIS is achieved through the installation process of inserting the cable GIS terminal into the input terminal of the combined electrical GIS. The end of the cable is installed as a cable GIS terminal, and the cable GIS terminal is fixed into the concave epoxy assembly of the input terminal of the combined electrical GIS by flanges and fixing bolts, thus realizing the connection between the cable and the GIS.

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