A method for reconstructing a cable terminal downlead structure based on an existing overhead transmission line

Abstract

This invention relates to the field of high-voltage transmission line technology, specifically providing a method for reconstructing the cable terminal downlead structure based on an existing overhead transmission line. The method includes removing excess conductor crossarms from the existing steel pipe pole main shaft, adding upper conductor downlead crossarms, middle conductor downlead crossarms, and cable terminal equipment crossarms, and adding a platform plate and a first and second cable clamp crossarm. The upper conductor is led through the upper conductor downlead crossarm to the inverted insulator string on the cable terminal equipment crossarm via a bare conductor; the middle conductor is led through the middle conductor downlead crossarm to the inverted insulator string; the lower conductor is directly led to the inverted insulator string and connected to the cable terminal and surge arrester; the underground cable is led to the cable terminal; and the ladder is replaced with a movable ladder. This invention eliminates the need to demolish old towers and build new ones, avoids increasing land area, significantly reduces construction costs, and solves the problems of narrow urban corridors, numerous underground pipelines, and the difficulty of building new cable terminal towers.

Description

Technical Field

[0001] This invention relates to the field of high-voltage transmission line technology, specifically to a method for reconstructing cable terminal lead-down structures based on existing overhead transmission lines. Background Technology

[0002] The conversion of existing overhead power transmission line terminal steel pipe poles in urban areas to cable terminal poles generally involves either building new towers or adding cable platforms on the ground. The first method requires constructing new towers, resulting in a long construction period and high costs. The second method requires a significantly larger land area, which is difficult to meet the operational needs in limited areas along urban roads or in green belts. Furthermore, the numerous underground pipelines in urban areas involve pipeline relocation, making the implementation plan costly and time-consuming.

[0003] In summary, there is an urgent need to provide a method for reconstructing cable terminal downlead structures based on existing overhead transmission lines in order to solve the technical problems existing in the prior art. Summary of the Invention

[0004] The purpose of this invention is to provide a method for reconstructing cable terminal downlead structures based on existing overhead transmission lines, in order to solve the technical problems existing in the prior art. The specific technical solution is as follows:

[0005] A method for reconstructing cable terminal downlead structures based on existing overhead transmission lines includes the following steps:

[0006] Step S1: Remove excess conductor crossarms from the main pole of the existing steel pipe pole;

[0007] Step S2: Add a new upper conductor lower crossarm at the end of the upper conductor crossarm, and add a new middle conductor lower crossarm at the end of the middle conductor crossarm.

[0008] Step S3: Add a new cable terminal equipment crossarm, which is connected to the existing steel pipe pole main pole through a locking assembly; the cable terminal base, surge arrester base and inverted insulator string hanging plate are installed on the cable terminal equipment crossarm;

[0009] Calculate the contact height of the locking assembly based on the weight of the equipment on the crossarm of the cable terminal equipment and the self-weight of the crossarm of the cable terminal equipment;

[0010] Step S4: Install the first cable clamp crossarm and the second cable clamp crossarm sequentially along the height direction on the existing steel pipe pole main pole using locking components. The first cable clamp crossarm and the second cable clamp crossarm are located below the cable terminal equipment crossarm. The end of the first cable clamp crossarm is provided with a clamp base, and the pole body of the second cable clamp crossarm is provided with a clamp base. Cable clamps are installed on the clamp bases.

[0011] Step S5: The upper conductor is led down the crossarm through the upper conductor and then through the bare conductor to the inverted insulator string on the crossarm of the cable terminal equipment. The middle conductor is led down the crossarm through the middle conductor and then to the inverted insulator string. The lower conductor is led directly to the inverted insulator string and connected to the cable terminal and surge arrester.

[0012] Step S6: Vertically guide the underground cable up to the cable terminal base through the cable clamps on the first cable clamp crossarm and the second cable clamp crossarm.

[0013] Step S7: Remove the ladder that interferes with the locking assembly and replace it with a movable ladder, which is connected to the main pole of the existing steel pipe pole through an adjustable connector.

[0014] Furthermore, the projections of the upper conductor lower crossarm and the middle conductor lower crossarm onto the horizontal plane are perpendicular to each other.

[0015] Furthermore, multiple cable terminal equipment crossarms are provided, and these multiple cable terminal equipment crossarms are arranged circumferentially along the main pole of the existing steel pipe pole, with the included angle between two adjacent cable terminal equipment crossarms being 40°-50°.

[0016] Furthermore, a platform plate is provided between the crossarms of two adjacent cable terminal equipment, and the platform plate forms an independent maintenance platform.

[0017] Furthermore, multiple first cable clamp crossarms are provided, and the multiple first cable clamp crossarms are arranged around the main pole of the existing steel pipe pole. The multiple first cable clamp crossarms correspond one-to-one with the crossarm of the cable terminal equipment.

[0018] Multiple second cable clamp crossarms are provided, and the multiple second cable clamp crossarms are arranged around the circumference of the main pole of the existing steel pipe pole. The multiple second cable clamp crossarms correspond one-to-one with the multiple first cable clamp crossarms.

[0019] Furthermore, at least one of the cable terminal equipment crossarm, the first cable clamp crossarm, and the second cable clamp crossarm is aligned with the direction of the upper conductor crossarm / middle conductor crossarm.

[0020] Furthermore, the locking assembly includes a clamp assembly one, which includes two polygonal clamps. The inner surface of the polygonal clamps matches the polygonal cross-section of the existing steel pipe pole main pole, and the two polygonal clamps are locked together by bolts to form a ring structure.

[0021] Furthermore, the clamp assembly is provided with multiple mounting slots, which are matched with the cable terminal equipment crossarm, the first cable clamp crossarm, or the second cable clamp crossarm.

[0022] Furthermore, in step S3, the contact height of the locking assembly is H1.

[0023] G1*L1+G2*L2=F1*H1 (Formula 1);

[0024] G1+G2=F1*H1*a*μ (Formula 2);

[0025] Where L1 and L2 are the equipment on the crossarm of the cable terminal equipment and the lever arm from the center of gravity of the crossarm to the main pole of the existing steel pipe pole, respectively; a is the side length of the contact surface between the polygonal clamp and the main pole of the existing steel pipe pole; and μ is the static friction coefficient.

[0026] Furthermore, in step S7, the adjustable connector includes a U-shaped clamp and a long bolt. The U-shaped clamp is locked to the movable ladder by the long bolt; the U-shaped clamp is fixedly connected to the main pole of the existing steel pipe pole.

[0027] The application of the technical solution of the present invention has the following beneficial effects:

[0028] (1) This invention provides a method for reconstructing cable terminal lead-down structures based on existing overhead transmission lines. This method is based on existing overhead transmission lines and does not require demolition of old towers or construction of new towers. It does not increase the land area, greatly reduces construction costs, and solves the problems of narrow urban corridors, numerous underground pipelines, and difficulty in constructing new cable terminal towers.

[0029] (2) In this invention, a platform plate is provided between the crossarms of two adjacent cable terminal equipment, and the platform plate forms an independent maintenance platform, which facilitates later maintenance operations.

[0030] (3) In this invention, by calculating the contact height of the locking assembly, the contact area between the polygonal clamp and the main pole of the existing steel pipe pole is ensured, thereby ensuring the reliability of the installation of the crossarm of the cable terminal equipment and meeting the actual operation requirements.

[0031] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0032] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0033] Figure 1 This is a flowchart of the method of the present invention;

[0034] Figure 2 This is a schematic diagram of the cable terminal lead-down structure based on the reconstruction of an existing overhead transmission line in this invention;

[0035] Figure 3 yes Figure 2Side view;

[0036] Figure 4 yes Figure 2 Schematic diagram of section AA in the diagram;

[0037] Figure 5 yes Figure 2 Schematic diagram of the BB section in the diagram;

[0038] Figure 6 yes Figure 2 Schematic diagram of the CC section in the diagram;

[0039] Figure 7 yes Figure 2 Schematic diagram of the DD section in the diagram;

[0040] Figure 8 yes Figure 2 Schematic diagram of the EE section in the diagram;

[0041] Figure 9 This is a top view of the connection between the crossarm of the cable terminal equipment and the main pole of the existing steel pipe pole;

[0042] Figure 10 yes Figure 9 The front view;

[0043] Figure 11 This is a top view schematic diagram showing the connection between the end of the upper conductor crossarm and the lower conductor crossarm;

[0044] Figure 12 yes Figure 11 A cross-sectional schematic diagram;

[0045] Figure 13 This is a structural diagram of the movable ladder;

[0046] Figure 14 This is a schematic diagram showing the connection between the movable ladder and the existing steel pipe pole main column;

[0047] Figure 15 This is a structural schematic diagram of the adjustable connector;

[0048] Among them, 1. Existing steel pipe pole main pole, 1.1. Upper conductor crossarm, 1.2. Middle conductor crossarm, 1.3. Lower conductor crossarm, 1.4. Excess conductor crossarm, 2. Upper conductor down-lead crossarm, 3. Middle conductor down-lead crossarm, 4. Cable terminal equipment crossarm, 4.1. Cable terminal base, 4.2. Lightning arrester base, 5. Locking assembly, 5.1. Polygonal clamp one, 5.2. Polygonal clamp two, 6. First cable clamp crossarm, 7. Second cable clamp crossarm, 8. Clamp base, 9. Movable ladder, 9.1. Central circular tube, 9.2. Horizontal tube, 10. Adjustable connector, 10.1. U-shaped clamp, 10.2. Long bolt, 11. Platform plate, 12. Clamp assembly two. Detailed Implementation

[0049] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered.

[0050] In the description of this invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "front", "back", "lateral", "longitudinal", 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.

[0051] Furthermore, the terms "first," "second," etc., 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 with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0052] Example:

[0053] See Figure 1 This embodiment provides a method for reconstructing the cable terminal downlead structure based on an existing overhead transmission line, including the following steps:

[0054] Step S1: Remove the excess conductor crossarm 1.4 from the existing main pole 1 of the steel pipe pole; in this embodiment, see... Figure 2 The main pole 1 of the existing steel pipe pole includes multiple parallel conductor crossarms, namely the upper conductor crossarm 1.1, the middle conductor crossarm 1.2, the lower conductor crossarm 1.3, and the redundant conductor crossarm 1.4 located below the lower conductor crossarm.

[0055] Step S2, see Figure 2 and Figure 3 In this embodiment, an upper conductor lower crossarm 2 is added to the end of the upper conductor crossarm 1.1, and a middle conductor lower crossarm 3 is added to the end of the middle conductor crossarm 1.2. In this embodiment, the upper conductor lower crossarm 2 and the middle conductor lower crossarm 3 are arranged horizontally. Preferably, the projections of the upper conductor lower crossarm 2 and the middle conductor lower crossarm 3 on the horizontal plane are perpendicular to each other. See also... Figure 7 and Figure 8 The upper conductor lower crossarm 2 and the upper conductor crossarm 1.1 are set vertically in the horizontal plane, and the middle conductor lower crossarm 3 is set along the extension direction of the middle conductor crossarm 1.2 to prevent the upper conductor and the lower conductor from affecting each other on the lower path.

[0056] In this embodiment, the upper conductor crossarm 1.1 and the upper conductor lower crossarm 2, as well as the middle conductor crossarm 1.2 and the middle conductor lower crossarm 3, are connected by clamp assembly 2 12. Clamp assembly 2 12 is respectively installed on the upper conductor crossarm 1.1 and the middle conductor crossarm 1.2. A connecting flange is provided on clamp assembly 2 12, and the connecting flange is connected to the upper conductor lower crossarm 2 / middle conductor lower crossarm 3 by bolts. (See [reference]). Figure 11 and Figure 12 .

[0057] Step S3: Add cable terminal equipment crossarm 4, see [link / reference] Figures 2-4 as well as Figure 9 and Figure 10 The cable terminal equipment crossarm 4 is connected to the existing steel pipe pole main pole 1 via a locking assembly 5. A cable terminal base 4.1, a surge arrester base 4.2, and an inverted insulator string hanging plate are installed on the cable terminal equipment crossarm 4. Correspondingly, a cable terminal is provided on the cable terminal base 4.1, a surge arrester is installed on the surge arrester base 4.2, and an inverted insulator string is installed on the inverted insulator string hanging plate. In this embodiment, three cable terminal equipment crossarms 4 are provided, arranged circumferentially along the existing steel pipe pole main pole 1. The included angle between two adjacent cable terminal equipment crossarms 4 is 40°-50°, preferably 45°. Cable terminal bases 4.1, surge arrester bases 4.2, and inverted insulator string hanging plates are symmetrically arranged on two adjacent cable terminal equipment crossarms 4.

[0058] As a preferred technical solution, the cable terminal equipment crossarm 4 located in the middle is set in the same direction as the conductor crossarm.

[0059] In this embodiment, see Figure 4 A platform plate 11 is provided between two adjacent cable terminal equipment crossarms 4, and the platform plate 11 forms an independent maintenance platform to facilitate later maintenance operations.

[0060] In this embodiment, see Figure 9 and Figure 10 The locking assembly 5 includes a clamp assembly one, which includes a polygonal clamp one 5.1 and a polygonal clamp two 5.2. The inner surfaces of the polygonal clamp one 5.1 and the polygonal clamp two 5.2 match the polygonal cross-section of the existing steel pipe pole main pole 1. The two polygonal clamps are locked together by bolts to form a ring structure.

[0061] Under the combined weight G1 of the equipment on the cable terminal equipment crossarm 4 and the self-weight G2 of the cable terminal equipment crossarm 4, a compressive force F1 is generated on the upper end of polygonal clamp 1 5.1 and the lower end of polygonal clamp 2 5.2 respectively. Polygonal clamp 1 5.1 and polygonal clamp 2 5.2 are in full contact with the existing steel pipe pole main rod 1, with a contact area of ​​H1*a, where H1 is the contact height of the locking assembly, and a is the side length of the contact surface between the polygonal clamp and the existing steel pipe pole main rod. The value of H1 is calculated by the following formula:

[0062] G1*L1+G2*L2=F1*H1 (Formula 1);

[0063] G1+G2=F1*H1*a*μ (Formula 2);

[0064] Where L1 and L2 are the lever arms of the equipment on the crossarm of the cable terminal equipment and the center of gravity of the crossarm to the main pole of the existing steel pipe pole, respectively; a is the side length of the contact surface between the polygonal clamp and the main pole of the existing steel pipe pole; and μ is the static friction coefficient.

[0065] The contact height of the locking component 5 is calculated using the above method to ensure the contact area between the polygonal clamp and the main pole of the existing steel pipe pole, thereby ensuring the reliability of the installation of the crossarm 4 of the cable terminal equipment and meeting the actual operation requirements.

[0066] Step S4, see Figure 2 and Figure 3 On the existing steel pipe pole main pole 1, a first cable clamp crossarm 6 and a second cable clamp crossarm 7 are sequentially installed along the height direction via locking components 5. The first cable clamp crossarm 6 and the second cable clamp crossarm 7 are located below the cable terminal equipment crossarm 4; in this embodiment, see... Figure 5 and Figure 6 There are 3 first cable clamp crossarms 6. The 3 first cable clamp crossarms 6 are arranged around the main pole 1 of the existing steel pipe pole. The 3 first cable clamp crossarms 6 correspond one-to-one with the cable terminal equipment crossarm 4 in the vertical direction. The first cable clamp crossarm 6 located in the middle is in the same direction as the conductor crossarm.

[0067] There are 3 second cable clamp crossarms 7, which are arranged around the main pole 1 of the existing steel pipe pole. The multiple second cable clamp crossarms 7 correspond one-to-one with the multiple first cable clamp crossarms 6 in the vertical direction; the second cable clamp crossarm 7 located in the middle is in the same direction as the conductor crossarm.

[0068] In this embodiment, see Figure 5 and Figure 6Each end of a plurality of first cable clamp crossarms 6 is provided with a clamp base 8, and a plurality of second cable clamp crossarms 7 are symmetrically provided with clamp bases 8; cable clamps are provided on the clamp bases 8 for fixing cables.

[0069] In this embodiment, see Figure 9 and Figure 10 The polygonal clamp 5.2 is provided with multiple mounting slots, which are matched with the cable terminal equipment crossarm 4, the first cable clamp crossarm 6 or the second cable clamp crossarm 7.

[0070] Step S5: The upper conductor is led down from the upper conductor crossarm 2 through a bare conductor to the inverted insulator string on the crossarm 4 of the cable terminal equipment. The middle conductor is led down from the middle conductor crossarm 3 to the inverted insulator string. The lower conductor is directly led to the inverted insulator string and connected to the cable terminal and surge arrester.

[0071] Step S6: The underground cable is vertically led up to the cable terminal base 4.1 through the cable clamps on the first cable clamp crossarm 6 and the second cable clamp crossarm 7.

[0072] Step S7: Remove the ladder that interferes with the locking assembly 5 and replace it with a movable ladder 9, which is connected to the existing steel pipe pole main pole 1 through multiple adjustable connectors 10.

[0073] In this embodiment, see Figures 13-15 The movable ladder 9 includes a central circular tube 9.1 and transverse tubes 9.2 staggered on opposite sides of the central circular tube 9.1. The adjustable connector 10 includes a U-shaped clamp 10.1 and a long bolt 10.2. The U-shaped clamp 10.1 engages with the central circular tube 9.1 and is locked by the long bolt 10.2. The U-shaped clamp 10.1 is fixedly connected to the connecting plate of the existing steel pipe pole main rod 1 by bolts. By setting the adjustable connector 10, the installation position of the movable ladder 9 can be adjusted to meet actual operation requirements. In addition, the U-shaped clamp 10.1 is first locked to the central circular tube 9.1 and then connected to the existing steel pipe pole main rod 1, which can solve the problem of installation difficulties caused by inaccurate measurement of pole dimensions and insufficient processing and welding precision, reduce the requirements for processing precision, and improve installation efficiency.

[0074] This invention is based on the transformation of existing overhead transmission line steel pipe poles into cable terminal downleading structures. It eliminates the need to demolish old towers and build new ones, without increasing the land area, thus significantly reducing construction costs and solving the problems of narrow urban corridors, numerous underground pipelines, and the difficulty of building new cable terminal towers.

[0075] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for reconstructing cable terminal lead-down structures based on existing overhead transmission lines, characterized in that, Includes the following steps: Step S1: Remove excess conductor crossarms from the main pole of the existing steel pipe pole; Step S2: Add a new upper conductor down crossarm at the end of the upper conductor crossarm, and add a new middle conductor down crossarm at the end of the middle conductor crossarm. Step S3: Add a new cable terminal equipment crossarm, which is connected to the existing steel pipe pole main pole through a locking assembly; the cable terminal base, surge arrester base and inverted insulator string hanging plate are installed on the cable terminal equipment crossarm; Calculate the contact height of the locking assembly based on the weight of the equipment on the crossarm of the cable terminal equipment and the self-weight of the crossarm of the cable terminal equipment; Step S4: Install the first cable clamp crossarm and the second cable clamp crossarm sequentially along the height direction on the existing steel pipe pole main pole using locking components. The first cable clamp crossarm and the second cable clamp crossarm are located below the cable terminal equipment crossarm. The end of the first cable clamp crossarm is provided with a clamp base, and the pole body of the second cable clamp crossarm is provided with a clamp base. Cable clamps are installed on the clamp bases. Step S5: The upper conductor is led down the crossarm through the upper conductor and then through the bare conductor to the inverted insulator string on the crossarm of the cable terminal equipment. The middle conductor is led down the crossarm through the middle conductor and then to the inverted insulator string. The lower conductor is led directly to the inverted insulator string and connected to the cable terminal and surge arrester. Step S6: Vertically guide the underground cable up to the cable terminal base through the cable clamps on the first cable clamp crossarm and the second cable clamp crossarm. Step S7: Remove the ladder that interferes with the locking assembly and replace it with a movable ladder, which is connected to the main pole of the existing steel pipe pole through an adjustable connector.

2. The method for reconstructing cable terminal lead-down structures based on existing overhead transmission lines according to claim 1, characterized in that, The projections of the upper conductor lower crossarm and the middle conductor lower crossarm on the horizontal plane are perpendicular to each other.

3. The method for reconstructing cable terminal lead-down structures based on existing overhead transmission lines according to claim 1, characterized in that, Multiple cable terminal equipment crossarms are provided, and the multiple cable terminal equipment crossarms are arranged circumferentially along the main pole of the existing steel pipe pole. The included angle between two adjacent cable terminal equipment crossarms is 40°-50°.

4. The method for reconstructing cable terminal lead-down structures based on existing overhead transmission lines according to claim 3, characterized in that, A platform plate is installed between the crossarms of two adjacent cable terminal equipment, and the platform plate forms an independent maintenance platform.

5. The method for reconstructing cable terminal lead-down structures based on existing overhead transmission lines according to claim 3, characterized in that, Multiple first cable clamp crossarms are provided, and multiple first cable clamp crossarms are arranged around the main pole of the existing steel pipe pole. Each of the multiple first cable clamp crossarms corresponds to a crossarm of the cable terminal equipment. Multiple second cable clamp crossarms are provided, and the multiple second cable clamp crossarms are arranged around the circumference of the main pole of the existing steel pipe pole. The multiple second cable clamp crossarms correspond one-to-one with the multiple first cable clamp crossarms.

6. The method for reconstructing cable terminal lead-down structures based on existing overhead transmission lines according to claim 5, characterized in that, At least one of the cable terminal equipment crossarm, the first cable clamp crossarm, and the second cable clamp crossarm is aligned with the direction of the upper conductor crossarm / middle conductor crossarm.

7. The method for reconstructing cable terminal lead-down structures based on existing overhead transmission lines according to claim 1, characterized in that, The locking assembly includes a clamp assembly one, which includes two polygonal clamps. The inner surface of the polygonal clamps matches the polygonal cross-section of the existing steel pipe pole main pole. The two polygonal clamps are locked together by bolts to form a ring structure.

8. The method for reconstructing cable terminal lead-down structures based on existing overhead transmission lines according to claim 7, characterized in that, The clamp assembly is provided with multiple mounting slots, which are matched with the crossarm of the cable terminal equipment, the first cable clamp crossarm, or the second cable clamp crossarm.

9. The method for reconstructing cable terminal lead-down structures based on existing overhead transmission lines according to claim 1, characterized in that, In step S3, the contact height of the locking assembly is H1. Formula 1); Formula 2); Where L1 and L2 are the lever arms of the equipment on the crossarm of the cable terminal equipment and the center of gravity of the crossarm to the main pole of the existing steel pipe pole, respectively; a is the side length of the contact surface between the polygonal clamp and the main pole of the existing steel pipe pole; μ is the static friction coefficient; G1 is the weight of the equipment on the crossarm of the cable terminal equipment; G2 is the self-weight of the crossarm of the cable terminal equipment; and F1 is the compressive force on the polygonal clamp under the action of the weight of the equipment on the crossarm of the cable terminal equipment and the self-weight of the crossarm of the cable terminal equipment.

10. The method for reconstructing cable terminal lead-down structures based on existing overhead transmission lines according to any one of claims 1-9, characterized in that, In step S7, the adjustable connector includes a U-shaped clamp and a long bolt. The U-shaped clamp is locked to the movable ladder by the long bolt. The U-shaped clamp is fixedly connected to the main pole of the existing steel pipe pole.

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