Extra-high voltage direct current porcelain insulator with optimized multi-umbrella skirt structure

Abstract

The invention discloses an extra-high voltage direct current porcelain insulator with an optimized multi-umbrella-skirt structure, and relates to the technical field of high-voltage power transmission, and the insulator comprises a solid porcelain insulator body, a metal flange assembly fixed at the bottom of the solid porcelain insulator body, and a screw assembly for fixing the flange assembly on a mounting table. The screw rod assembly comprises a central screw rod and peripheral screw rods which are annularly arranged, the self-adaptive radial reinforcing assembly is further included, the extension section of the screw rod is sleeved with an abutting sleeve, a folding mechanism which is initially in a V shape is hinged between the abutting sleeves, and the folding mechanism is connected with the metal flange assembly through a hanging rod; the flange assembly pulls the folding mechanism to be flattened through the hanging rod, the abutting sleeve is driven to apply radial thrust to the screw rod, the screw rod is deformed to increase the locking force, and passive self-locking is achieved. According to the invention, the problem that the bottom connection of the extra-high voltage insulator is easy to loosen and age under large-tonnage tension is effectively solved, and the anti-pulling performance is obviously improved.

Description

Technical Field

[0001] This invention relates to the field of high-voltage power transmission technology, and in particular to an ultra-high voltage direct current porcelain insulator with an optimized multi-skirt structure and its bottom connection reinforcement structure. Background Technology

[0002] Ultra-high voltage direct current (UHVDC) transmission technology has become an important component of modern power grids due to its advantages such as large transmission capacity, long distance, and low loss. Porcelain insulators, as key components in transmission lines, serve a dual function of electrical insulation and mechanical support. In UHVDC projects, insulators typically employ a solid rod-shaped structure with multiple awnings, resulting in significant weight and the ability to withstand enormous mechanical tensile loads.

[0003] In actual operation, the cables fixed to UHVDC porcelain insulators are often hundreds or even thousands of meters long. Even slight fluctuations in the cable caused by wind can generate enormous axial tensile forces (pull-out forces) and bending moments when transmitted to the insulator base. Existing porcelain insulators are typically fixed to the tower mounting platform via metal flange assemblies and bolt and nut assemblies. However, over time, long-term exposure to wind, rain, and mechanical vibration can cause the bolt and nut assemblies to age, corrode, and even loosen. Relying solely on the friction of the threaded engagement becomes increasingly unreliable when facing such enormous axial tensile forces. Once the bottom connection becomes loose, it will seriously threaten the safety of the transmission line, leading to frequent inspections and maintenance, and increasing operation and maintenance costs.

[0004] Furthermore, the connection between the insulator body (ceramic component) and the metal flange is typically secured with cement. While this provides a certain level of strength, there is still a risk that the ceramic component may be pulled out of the flange under extreme axial tensile forces. Therefore, there is an urgent need for a structure that can simultaneously enhance the connection strength between the insulator body and the flange, as well as between the flange and the mounting platform. Summary of the Invention

[0005] The purpose of this invention is to provide a porcelain insulator for ultra-high voltage direct current with an optimized multi-skirt structure. By improving the bottom connection structure and utilizing the mechanical linkage principle, the self-locking ability of the insulator under axial tensile force is improved, thus solving the problem of easy aging and loosening of existing connection methods.

[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution: a porcelain insulator for ultra-high voltage direct current with an optimized multi-skirt structure, comprising a porcelain insulator body, a metal flange assembly fixedly connected to the bottom of the porcelain insulator body, and a screw assembly for fixing the metal flange assembly to a mounting platform. The porcelain insulator body comprises a solid porcelain column and a plurality of skirts integrally fired along its axial direction. A cable seat is provided at the top of the porcelain insulator body. The screw assembly comprises a central screw that penetrates the mounting platform and extends downward, and a plurality of peripheral screws arranged in a circular array around the central screw. The top end of the central screw passes through the metal flange assembly and is fixedly connected to the bottom of the porcelain insulator body. The top end of the peripheral screw is provided with a limiting screw head and abuts against the upper surface of the metal flange assembly. The central screw and the peripheral screw are threaded with fastening nuts at the positions below the mounting platform. The insulator also includes an adaptive radial reinforcement assembly, which includes a pressure sleeve threaded onto the central screw and the peripheral screw extension, a folding mechanism connecting the pressure sleeve on the central screw and the pressure sleeve on the peripheral screw, and a hanger connecting the folding mechanism and the metal flange assembly. When the metal flange assembly is subjected to an axial tensile force away from the mounting platform, the metal flange assembly pulls the folding mechanism to deform through the hanger rod, causing the pressure sleeves connected to both ends of the folding mechanism to apply radial thrust to the central screw and the peripheral screw respectively.

[0007] Furthermore, a plurality of the pressure sleeves are provided axially spaced on the extension section of the central screw, and the number of pressure sleeves on the central screw is the same as the number of the peripheral screws; Each of the peripheral screws has a pressure sleeve on its extension section; Each of the peripheral screws has a corresponding and equal-height abutment sleeve at a different height on the central screw; A folding mechanism is connected between every two equal-height pressure sleeves. The two ends of the folding mechanism are respectively hinged to the two pressure sleeves, and the middle part of the folding mechanism is bent downward into a V-shape. The upper end of the boom is connected to the bottom of the metal flange assembly, and the lower end of the boom is connected to the bend in the middle of the folding mechanism.

[0008] Furthermore, the pressure sleeve includes a screw-on sleeve with internal threads, two C-shaped clamps, and a bolt and nut assembly; The outer wall of the screw-on sleeve is provided with an annular groove. After the two clamps are closed, they are embedded in the annular groove and fixed by the bolt and nut assembly. The end of the folding mechanism is hinged to the clamp.

[0009] Furthermore, both ends of the clamp are integrally provided with lugs. When the two clamps are closed, the corresponding lugs fit together, and the bolt and nut assembly passes through the lugs to lock and fix the two clamps.

[0010] Furthermore, the bottom of the porcelain insulator body is integrally fired with a plug post, the end of the plug post is provided with a radially expanded locking joint, and the bottom of the locking joint is provided with a connecting cavity.

[0011] Furthermore, the metal flange assembly includes a flange cylinder and a flange plate integrally disposed at the bottom of the flange cylinder; The top end of the central screw extends through the flange into the interior of the flange cylinder, and a ball is integrally provided at the top end of the central screw; The insertion post and locking joint are inserted into the flange cylinder, and the ball extends into the connection cavity.

[0012] Furthermore, adhesive is filled between the sphere and the connecting cavity, and between the locking joint and the flange cylinder, which, after curing, forms a double wedge-shaped locking structure to prevent the porcelain insulator body from separating from the metal flange assembly.

[0013] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention, by setting up an adaptive radial reinforcement component, utilizes the linkage transmission principle to convert the axial tensile force on the insulator into a radial thrust on the fixing screw. When the flange assembly tends to be pulled upwards, the lifting rod pulls the V-shaped folding mechanism to flatten, thereby opening the pressure sleeves at both ends. This structure ensures that the greater the outward pulling force on the flange, the greater the radial compressive force on the screw, thus increasing the friction and engagement force between the screw and the mounting hole and fasteners, achieving passive mechanical self-locking and effectively preventing connection failure caused by loose or aging nuts.

[0014] 2. This invention enhances pull-out resistance through the elastic or plastic deformation of the central and peripheral screws under stress. Under extreme tensile force, radial thrust causes the screws to bend (e.g., S-shaped slight deformation). This deformation constitutes a rigid interlock, ensuring that even if the fastening nut completely fails, the deformed screw cannot be pulled out of the mounting hole, greatly improving the safety of the connection structure.

[0015] 3. This invention enhances the bonding strength between the porcelain insulator body and the metal flange assembly through a special internal connection structure. By utilizing the ball at the top of the central screw extending into the connecting cavity at the bottom of the porcelain component, and the locking joint at the bottom of the porcelain component extending into the flange cylinder, combined with adhesive curing, a double wedge-shaped locking structure is formed: "metal ball head locking the porcelain component" and "porcelain component joint locking the flange." This structure uses geometric mechanical obstruction to prevent the porcelain component from slipping out of the flange, solving the problem of insufficient tensile strength in the adhesive-coated parts of large-tonnage ultra-high voltage insulators. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall three-dimensional structure of a porcelain insulator for ultra-high voltage direct current with an optimized multi-skirt structure according to the present invention. Figure 2 This is a three-dimensional structural diagram of the porcelain insulator body in this invention; Figure 3 This is a three-dimensional structural diagram of the flange assembly and the mounting reinforcement assembly in this invention (partial cross-section to show the internal spherical connection). Figure 4 This is a bottom-view three-dimensional structural diagram of the installation of the reinforcement components in this invention; Figure 5 This is a three-dimensional structural diagram of the cooperation between the pressure sleeve and the folding mechanism in this invention; Figure 6 This is an exploded structural diagram of the pressure sleeve in this invention.

[0017] In the diagram: 1. Porcelain column; 2. Umbrella skirt; 3. Cable socket; 4. Plug-in post; 5. Locking joint; 501. Connecting cavity; 6. Flange cylinder; 7. Flange; 8. Screw head; 9. Peripheral screw; 10. Mounting platform; 11. Fastening nut; 12. Pressure sleeve; 1201. Tightening sleeve; 1202. Hoop; 1203. Lug; 1204. Bolt and nut assembly; 13. Folding mechanism; 14. Hanging rod; 15. Central screw; 16. Sphere. Detailed Implementation

[0018] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0019] In the description of this invention, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0021] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0022] like Figures 1 to 6 As shown, this invention provides a porcelain insulator for ultra-high voltage direct current (UHVDC) with an optimized multi-skirt structure. The insulator mainly consists of an insulator body, a metal flange assembly, a mounting screw assembly, and an adaptive radial reinforcement assembly.

[0023] The insulator body, serving as the core insulation and support component, includes a solid porcelain column 1. To increase the creepage distance for use in ultra-high voltage direct current environments, several awnings 2 are integrally fired along the axial direction on the outer circumference of the porcelain column 1. A cable holder 3 for fixing the transmission cable is provided at the top of the porcelain column 1. The bottom of the porcelain column 1 has a special connection structure, specifically including a plug-in post 4 integrally fired at the bottom end of the porcelain column 1. The end of the plug-in post 4 is further provided with a radially enlarged locking joint 5, the bottom center of which is recessed inward, forming a connection cavity 501.

[0024] The metal flange assembly is fixedly installed at the bottom of the insulator body for connecting to an external mounting platform 10 (such as a power tower crossarm). The metal flange assembly includes a cylindrical flange 6 and a flange plate 7 integrally formed at the bottom of the flange 6. The insertion post 4 and locking joint 5 at the bottom of the insulator body are inserted into the internal cavity of the flange 6.

[0025] To securely fix the metal flange assembly to the mounting platform 10, this invention employs a special screw assembly. This assembly includes a central screw 15 and several peripheral screws 9. The central screw 15 is located on the central axis of the flange 7, and the peripheral screws 9 are evenly distributed in a ring array around the central screw 15. A hexagonal limiting screw head 8 is integrally provided at the top of each peripheral screw 9. In the installed state, the central screw 15 and the peripheral screws 9 penetrate from top to bottom through the flange 7 and the mounting platform 10. The limiting screw heads 8 at the top of the peripheral screws 9 abut against the upper surface of the flange 7, thereby preventing the peripheral screws 9 from falling downwards. Below the mounting platform 10, each screw is screwed with a fastening nut 11. By tightening the fastening nuts 11, the flange 7 is clamped and fixed to the mounting platform 10.

[0026] This invention constructs an internal double-locking structure between the insulator body and the metal flange assembly. Specifically, the top of the central screw 15 passes through the flange 7 and extends into the interior of the flange cylinder 6, with a ball 16 integrally formed at its top. During assembly, the ball 16 extends into the connecting cavity 501 at the bottom of the locking joint 5. Subsequently, a high-strength adhesive (such as cement adhesive) is filled into the gaps between the ball 16 and the connecting cavity 501, and between the locking joint 5 and the inner wall of the flange cylinder 6. After the adhesive cures, the ball 16 is locked in the connecting cavity 501 and cannot be pulled out; at the same time, the enlarged locking joint 5 is also locked in the flange cylinder 6 and cannot be pulled out. This structure utilizes the mechanical obstruction of geometric shapes to form a double wedge-shaped lock from the inside out, preventing the ceramic column 1 from slipping out of the flange cylinder 6 even when the adhesive ages.

[0027] To address the problem of easy loosening of the bottom connection of insulators in ultra-high voltage direct current (UHVDC) lines, this invention incorporates an adaptive radial reinforcement component below the mounting platform 10. For example... Figure 3 and Figure 4 As shown, the central screw 15 and the peripheral screw 9 extend downwards for a distance after passing through the fastening nut 11. Pressure sleeves 12 are installed on these extensions.

[0028] like Figure 6As shown, the specific structure of the pressure sleeve 12 includes a screw-on sleeve 1201, two semi-circular C-shaped clamps 1202, and a bolt and nut assembly 1204. The inner wall of the screw-on sleeve 1201 has internal threads, allowing it to be threaded onto the screw rod and its height position in the screw rod axially adjusted by rotation. The outer wall of the screw-on sleeve 1201 has an annular groove with an I-shaped cross-section. When the two clamps 1202 are closed, their inner edges are embedded in the annular groove, thus allowing the screw-on sleeve 1201 to rotate relative to the clamps 1202 while maintaining connection with the screw-on sleeve 1201. Both ends of the clamps 1202 have lugs 1203, and the bolt and nut assembly 1204 passes through the lugs 1203 to lock and fix the two clamps 1202 in place.

[0029] To achieve multi-point linkage, multiple pressure sleeves 12 are provided on the central screw 15 at axial intervals, the number of which is equal to the number of peripheral screws 9. Each peripheral screw 9 is provided with a pressure sleeve 12, and the height of the pressure sleeve 12 is equal to the height of one of the pressure sleeves 12 on the central screw 15, thus forming a one-to-one equal height fit.

[0030] Between each pair of equal-height pressure sleeves 12, a folding mechanism 13 is connected. The folding mechanism 13 consists of two connecting rods, the two ends of which are respectively hinged to the hoop 1202 of the central screw 15 and the peripheral screw 9. The middle part of the folding mechanism 13 is connected by a hinge shaft, and in the initial installation state, the middle part of the folding mechanism 13 is bent downward, forming an overall "V" shape.

[0031] Several vertically downward-pointing lifting rods 14 are fixedly connected to the bottom of the flange 7. The lifting rods 14 pass through pre-drilled holes on the mounting platform 10 (or avoid the mounting platform), and their lower ends are connected to the bends in the middle of a corresponding set of folding mechanisms 13. It should be particularly noted that the lifting rods 14, as key transmission components that convert the axial displacement of the flange assembly into radial locking force, have crucial mechanical properties. In this embodiment, the lifting rods 14 are preferably made of high-strength alloy steel or heat-treated carbon steel, and their tensile strength is calculated and designed to overcome the resistance required for the flattening deformation of the folding mechanism 13 and the deformation of the screw pushed by the pressure sleeve 12 when the flange 7 tends to move upwards, without fracturing or plastically elongating.

[0032] The working principle of this invention is as follows: When ultra-high voltage transmission cables are affected by wind deflection or galloping, generating a huge axial tensile force on the insulator (i.e., a pull-out force away from the mounting platform 10), this tensile force is first transmitted to the insulator body and then to the metal flange assembly. Under the action of the tensile force, the flange 7 will produce a slight upward displacement or displacement tendency.

[0033] At this time, the lifting rod 14 fixed to the bottom of the flange 7 moves upward, lifting the middle bending point of the folding mechanism 13. Because the lifting rod 14 has extremely high tensile strength, it will not break during the upward movement, but will force the "V"-shaped folding mechanism 13 to tend towards a horizontal flattened state.

[0034] As the folding mechanism 13 changes from a "V" shape to an "I" shape, its horizontal span gradually increases, thereby generating a huge radial thrust on the pressure sleeves 12 connected to its two ends. This thrust is perpendicular to the screw axis, pushing the peripheral screws 9 outwards and simultaneously pushing the central screw 15 in various directions (since the central screw 15 connects to the folding mechanism 13 in multiple directions, its stress state is more complex).

[0035] Under the action of huge radial thrust, the peripheral screw 9 and the central screw 15 will undergo elastic bending deformation or plastic bending deformation (e.g., micro S-shaped bending). This deformation generates great lateral compressive force and friction between the screw and the mounting hole wall on the mounting platform 10, as well as the thread of the fastening nut 11, forming a rigid mechanical interlock.

[0036] Therefore, the greater the axial pull-out force on the insulator, the greater the force that pulls the folding mechanism 13 upwards on the rod 14, and consequently the greater the radial locking force. This passive adaptive locking mechanism can still ensure the stability of the bottom connection of the insulator and prevent the insulator from falling off even if the fastening nut 11 becomes loose or fails due to long-term vibration or corrosion. This significantly reduces the operation and maintenance risks and maintenance frequency of UHVDC transmission lines.

[0037] In summary, this invention prevents insulator loosening through a dual internal and external structure. Internally, the ball 16 extending into the connecting cavity 501 and the locking joint 5 extending into the flange cylinder 6, combined with adhesive curing, form a physical barrier to prevent the porcelain insulator body from being pulled out of the metal flange assembly. Externally, the hanger 14 converts the outward pulling force on the flange assembly into a flattening action of the folding mechanism 13. This action drives the pressure sleeve 12 to radially push the peripheral screw 9 and the central screw 15, forcing the screws to bend and deform within the mounting hole. This deformation increases the friction and engagement force between the screws and the mounting platform 10, and can also achieve passive self-locking by deforming and locking when the fastening nut 11 fails.

[0038] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A porcelain insulator for ultra-high voltage direct current with an optimized multi-skirt structure, comprising a porcelain insulator body, a metal flange assembly fixedly connected to the bottom of the porcelain insulator body, and a screw assembly for fixing the metal flange assembly to a mounting platform (10), wherein the porcelain insulator body comprises a solid porcelain column (1) and a plurality of skirts (2) integrally fired along its axial direction, and a cable seat (3) is provided at the top of the porcelain insulator body, characterized in that: The screw assembly includes a central screw (15) that passes through the mounting platform (10) and extends downward, and a plurality of peripheral screws (9) arranged in a ring array with the central screw (15) as the center. The top end of the central screw (15) passes through the metal flange assembly and is fixedly connected to the bottom of the porcelain insulator body. The top end of the peripheral screw (9) is provided with a limiting screw head (8) and abuts against the upper surface of the metal flange assembly. The central screw (15) and the peripheral screw (9) are threaded with fastening nuts (11) at the position below the mounting platform (10). The insulator also includes an adaptive radial reinforcement assembly, which includes a pressure sleeve (12) threaded onto the extensions of the central screw (15) and the peripheral screw (9), a folding mechanism (13) connecting the pressure sleeve (12) on the central screw (15) and the pressure sleeve (12) on the peripheral screw (9), and a hanger (14) connecting the folding mechanism (13) to the metal flange assembly. When the metal flange assembly is subjected to an axial tensile force away from the mounting platform (10), the metal flange assembly pulls the folding mechanism (13) to deform through the hanger (14), causing the pressure sleeves (12) connected to both ends of the folding mechanism (13) to apply radial thrust to the central screw (15) and the peripheral screws (9) respectively.

2. The ultra-high voltage direct current porcelain insulator with an optimized multi-skirt structure according to claim 1, characterized in that, The extension of the central screw (15) is provided with a plurality of the pressure sleeves (12) spaced apart along the axial direction, and the number of pressure sleeves (12) on the central screw (15) is the same as the number of the peripheral screws (9); Each of the peripheral screws (9) has a pressure sleeve (12) on its extension section. Each of the peripheral screws (9) has a pressure sleeve (12) that corresponds to a pressure sleeve (12) at a different height on the central screw (15) and is set at the same height. A folding mechanism (13) is connected between every two equal-height pressure sleeves (12). The two ends of the folding mechanism (13) are respectively hinged to the two pressure sleeves (12), and the middle part of the folding mechanism (13) is bent downward into a V-shaped structure. The upper end of the boom (14) is connected to the bottom of the metal flange assembly, and the lower end of the boom (14) is connected to the bend in the middle of the folding mechanism (13).

3. The ultra-high voltage direct current porcelain insulator with an optimized multi-skirt structure according to claim 1, characterized in that, The pressure sleeve (12) includes a screw-on sleeve (1201) with internal threads, two C-shaped clamps (1202), and a bolt and nut assembly (1204). The outer wall of the screw sleeve (1201) is provided with an annular groove. After the two clamps (1202) are closed, they are embedded in the annular groove and fixed by the bolt and nut assembly (1204). The end of the folding mechanism (13) is hinged to the clamp (1202).

4. The ultra-high voltage direct current porcelain insulator with an optimized multi-skirt structure according to claim 3, characterized in that, Both ends of the clamp (1202) are integrally provided with lugs (1203). After the two clamps (1202) are closed, the corresponding lugs (1203) fit together. The bolt and nut assembly (1204) passes through the lugs (1203) to lock and fix the two clamps (1202).

5. A porcelain insulator for ultra-high voltage direct current with an optimized multi-skirt structure according to claim 1, characterized in that, The bottom of the porcelain insulator body is integrally fired with a plug post (4), the end of the plug post (4) is provided with a radially expanded locking joint (5), and the bottom of the locking joint (5) is provided with a connecting cavity (501).

6. The ultra-high voltage direct current porcelain insulator with an optimized multi-skirt structure according to claim 5, characterized in that, The metal flange assembly includes a flange cylinder (6) and a flange plate (7) integrally disposed at the bottom of the flange cylinder (6). The top end of the central screw (15) extends through the flange (7) into the interior of the flange cylinder (6), and a ball (16) is integrally provided on the top end of the central screw (15). The insertion post (4) and the locking joint (5) are inserted into the flange cylinder (6), and the ball (16) extends into the connecting cavity (501).

7. A porcelain insulator for ultra-high voltage direct current with an optimized multi-skirt structure according to claim 6, characterized in that, The space between the sphere (16) and the connecting cavity (501), as well as between the locking joint (5) and the flange cylinder (6), is filled with adhesive, which, after curing, forms a double wedge-shaped locking structure to prevent the porcelain insulator body from separating from the metal flange assembly.

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