Structure for converting double-loop tower overhead line into double-spliced cable leading-down

Abstract

The invention discloses a down-leading structure for converting a double-loop tower overhead line into a double-spliced cable, and belongs to the technical field of power transmission lines, the down-leading structure comprises a double-loop cable terminal tower, and the double-loop cable terminal tower is sequentially provided with a ground wire cross arm and three layers of wire cross arms including an upper layer, a middle layer and a lower layer from top to bottom; the two sides of each wire cross arm are respectively provided with a wire hanging point to form six wire hanging points in double loops; the lead of the upper-layer lead cross arm hanging point passes through the strain insulator string and then sequentially passes through the double-cross-arm type supporting insulators arranged on the middle-layer lead cross arm and the lower-layer lead cross arm to be led down to a double-spliced cable terminal head; a wire of a middle-layer wire cross arm hanging point is led down to a double-spliced cable terminal through a strain insulator string and a double-cross-arm type supporting insulator arranged on the lower-layer wire cross arm; and the lead of the lower-layer lead cross arm hanging point passes through the strain insulator string and then is directly led down to the double-spliced cable terminal head. According to the invention, the safety distance of the down lead in the process of converting the double-loop tower overhead line into the double-spliced cable can be ensured, and the down lead problem of the double-spliced cable is effectively solved.

Description

Technical Field

[0001] The invention relates to a double-circuit tower overhead line conversion into a double-spliced ​​cable downleading structure, belonging to the technical field of power transmission lines. Background Art

[0002] The transmission capacity of urban power grids has increased and the construction of overhead lines in urban areas has become increasingly difficult. On the one hand, it has become extremely difficult to find a suitable overhead line path, which requires crossing many buildings, roads and other urban infrastructure. This not only increases the construction cost, but also may cause a series of safety hazards and aesthetic problems; on the other hand, with the improvement of environmental protection requirements and the need for urban landscape construction, the existence of overhead lines in urban areas has also been subject to more restrictions. As one of the important ways of power transmission, the current carrying capacity of a single cable is limited. In the face of the growing demand for power transmission, a single cable often cannot bear the transmission capacity that matches the overhead line. Against this background, the number of application scenarios where four-split overhead lines need to be converted into double-split cable lines is gradually increasing.

[0003] In transmission lines, overhead lines usually need to be converted to cable lines through cable terminal towers so that electric energy can be smoothly transmitted underground. When the overhead line that needs to be led down is a four-split conductor, the fixed wire clamp at the end of the conventional cross-arm support insulator is only designed for two conductors, and the equipment wire clamps used for connecting the conductors at the cable terminal head are only single-conductor equipment wire clamps and double-conductor equipment wire clamps. If the four-split conductor is to be smoothly led down, from the perspective of technology and equipment compatibility, it is a more reasonable and feasible way to convert the four-split conductor into two double-split conductors and then lead them down. This conversion method can better adapt to the existing insulator and equipment clamp conditions, ensure the safety and stability of the lead-down process, and provide strong guarantees for the efficient operation of urban power grids. Summary of the invention

[0004] The purpose of the present invention is to overcome the problem of converting overhead lines into double-split cables in the prior art, and the problem that the four-split conductors of the cable terminal tower are difficult to lead down, and how to achieve a straight and smooth transition of the down lead from the overhead line to the double-split cable terminal head to ensure the reliability and safety of the four-split conductor when being led down.

[0005] In order to solve the above technical problems, the present invention is implemented by adopting the following technical solutions: A double-circuit tower overhead line is converted into a double-spliced ​​cable down-leading structure, comprising: a double-circuit cable terminal tower, wherein the double-circuit cable terminal tower is provided with a ground wire cross arm and an upper conductor cross arm, a middle conductor cross arm, and a lower conductor cross arm in sequence from top to bottom, and a conductor hanging point is provided on both sides of each conductor cross arm to form a double circuit with a total of six conductor hanging points; The conductor at the upper conductor cross arm hanging point is led down to the double-jointed cable terminal head through a tension insulator string, and then sequentially through the middle conductor cross arm and the double cross arm support insulator arranged on the lower conductor cross arm; The conductor at the middle conductor cross arm hanging point passes through the tension insulator string and the suspended tension string, and then passes through the double cross arm support insulator arranged on the lower conductor cross arm and is led down to the double cable terminal head; The conductors at the lower conductor cross arm hanging points are directly led down to the double-jointed cable terminal heads after passing through the tension insulator strings.

[0006] The aforementioned double-circuit tower overhead line is converted into a double-cable downlead structure, and a cable terminal platform is arranged for each phase conductor along the direction of the overhead line. Two cable terminal heads of the double-cable are arranged on each cable terminal platform perpendicular to the direction of the overhead line.

[0007] The aforementioned double-circuit tower overhead line is converted into a double-cable downconducting structure, and also includes a lightning arrester, which is arranged between two cable terminal heads, and the downconductor is converted into a double-cable through the cable terminal heads.

[0008] The aforementioned double-circuit tower overhead line is converted into a double-cable downlead structure, and double cross-arm support insulators are respectively arranged on the cable side of the middle conductor cross arm and the lower conductor cross arm, and the double cross-arm support insulators are arranged horizontally in parallel; The conductor at the upper conductor crossarm hanging point transitions from four-split to two double-split down conductors after passing through the four-split jumper spacer; the two double-split down conductors are respectively led down through the double crossarm support insulators of the middle conductor crossarm and the lower conductor crossarm, and connected to the cable terminal head.

[0009] The aforementioned double-circuit tower overhead line is converted into a double-split cable downlead structure, and a jumper string is arranged on the double-split downlead at the lead-out point of the four-split jumper spacer bar.

[0010] The aforementioned double-circuit tower overhead line is converted into a double-split cable down-lead structure, and the conductor at the middle-layer conductor crossarm hanging point is transitioned from four-split to two double-split down-leads after passing through a four-split jumper spacer; the two double-split down-leads are respectively led down through the double cross-arm support insulators of the lower-layer conductor crossarm and connected to the cable terminal head.

[0011] The aforementioned double-circuit tower overhead line is converted into a double-spliced ​​cable downlead structure, and a suspended tension string is provided at the middle-layer conductor crossarm hanging point and the double-split downlead at the four-split jumper spacer lead-out point.

[0012] The aforementioned double-circuit tower overhead line is converted into a double-split cable downlead structure, and the conductors at the lower conductor crossarm hanging point are transitioned from four splits to two double-split downleads after passing through a four-split jumper spacer, and then connected to the cable terminal head.

[0013] The aforementioned double-circuit tower overhead line is converted into a double-split cable downconductor structure, each double-split downconductor is connected to one of the cable terminal heads using a double-conductor copper-aluminum transition device clamp, and each double-split downconductor is connected to the arrester drainage line via a double-conductor T-type clamp.

[0014] The aforementioned double-circuit tower overhead line is converted into a double-cable downlead structure, and the lightning arrester is connected to the lightning arrester drainage line through a copper-aluminum transition device wire clamp.

[0015] The aforementioned double-circuit tower overhead line is converted into a double-spliced ​​cable downlead structure, a downlead bracket is arranged at the lower part of the lower conductor crossarm, and double crossarm support insulators are arranged on both sides of the downlead bracket, and the double crossarm support insulators of the downlead bracket are arranged in parallel with the double crossarm support insulators of the middle conductor crossarm and the lower conductor crossarm; The conductors at the upper conductor cross arm hanging points are led down to the double-jointed cable terminal head through the tension insulator string, the double cross arm support insulators of the middle conductor cross arm, the double cross arm support insulators of the lower conductor cross arm, and the double cross arm support insulators of the down-lead support; The conductors at the middle conductor cross arm hanging points are led down to the double-jointed cable terminal head through the tension insulator string, the double cross arm support insulators of the lower cross arm, and the double cross arm support insulators of the down conductor support; The conductors at the lower conductor cross-arm hanging points are led down to the double-jointed cable terminal heads via tension insulator strings and double cross-arm support insulators of down-lead brackets.

[0016] The beneficial effects achieved by the present invention are as follows: the down-conducting structure of the present invention solves the problem that it is difficult to lead down the four-split conductors of the cable terminal tower through the down-conducting points and structural design of the upper conductor crossarm, the middle conductor crossarm and the lower conductor crossarm, and can effectively realize the straight and smooth transition of the down-conducting wires from the overhead line to the double-split cable terminal head. The double-cross-arm supporting insulator ensures the electrical clearance between the down-conducting wire and the tower body; and there is no crossing between the down-conducting wires. After the conductors of each phase are led down, they are respectively connected to the double-split cables in parallel with the same phase, thereby ensuring the reliability and safety of the four-split conductors when being led down. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a front view of the upper conductor lead-down structure of a double-circuit tower overhead line converted into a double-cable lead-down structure provided by the first embodiment of the present invention; Figure 2 It is a front view of a middle-layer conductor lead-down structure of a double-circuit tower overhead line converted into a double-spliced ​​cable lead-down structure provided by the first embodiment of the present invention; Figure 3 It is a front view of the lower conductor lead-down of a double-circuit tower overhead line converted into a double-cable lead-down structure provided by the first embodiment of the present invention; Figure 4This is a side view of the upper, middle and lower conductors provided in the first embodiment of the present invention; Figure 5 It is a detailed connection diagram of the down conductor, the cable terminal head and the lightning arrester on the cable terminal platform provided in the second embodiment of the present invention; Figure 6 It is a top view of the cable terminal platform provided in the second embodiment of the present invention.

[0018] Figure numerals: 1. Strain insulator string; 2. Jumper string; 3. Down conductor; 4. Drainage wire for lightning arrester; 5. Suspension strain string; 6. Cross-arm supporting insulator 7. Four-split jumper spacer; 8. Double-split jumper spacer; 9. Cable terminal head; 10. Lightning arrester; 11. Double-conductor T-type wire clamp; 12. Double-conductor copper-aluminum transition equipment wire clamp; 13. Copper-aluminum transition equipment wire clamp; 14. Cable. DETAILED DESCRIPTION

[0019] The technical solution of the present invention is further described below in conjunction with specific embodiments. Example 1

[0020] like Figure 1-4 As shown, double circuit 220kV overhead line 4×630mm 2 The conductor lead-in is double 2500mm 2 Cable is used as an example. In this example, a double-circuit tower overhead line with double cross-arm support insulators is converted into a double-split cable lead-in structure. The double-circuit cable terminal tower is provided with a ground wire cross-arm and three layers of conductor cross-arms, upper, middle and lower, from top to bottom. A conductor hanging point is provided on both sides of each conductor cross-arm, forming a total of six conductor hanging points for the double circuit. The conductor at the lead-out point adopts a four-split conductor; the left and right sides of the tower are provided with cable terminal platforms.

[0021] The conductor at the upper conductor crossarm hanging point passes through the tension insulator string 1 hung on the overhead line side and then jumps to the cable side through the jumper string 2, and then transitions from four-split to two double-split down conductors 3 through the four-split jumper spacer 7, and is led down to the double-split cable terminal head 9 through the double crossarm support insulator 6 arranged on the cable side of the middle conductor crossarm and the lower conductor crossarm, and is converted into a cable 14 through the cable terminal head 9 and led down from the terminal platform; the double crossarm support insulator 6 is arranged horizontally in parallel; the down conductor between the tension insulator string 1 and the jumper string 2 adopts a four-split jumper spacer 7, and the down conductor between the jumper string 2 and the cable terminal head 9 adopts a double-split jumper spacer 8.

[0022] The conductor at the middle-layer conductor cross arm hanging point jumps to the suspended tension string 5 suspended on the side of the middle-layer cross arm through the tension insulator string 1 hung on the overhead line side, and then transitions from four splits to two double split down conductors 3, which are led down to the double-split cable terminal head 9 through the double cross arm support insulator 6 set on the side of the lower conductor cross arm, and then converted into a cable 14 through the cable terminal head 9 and led down from the terminal platform; the down conductor between the cross arm support insulator 6 and the cable terminal head 9 adopts a double split jumper spacer 8. The double cross arm support insulator can ensure the electrical clearance of the down conductor to the tower body.

[0023] The conductor at the lower conductor cross arm hanging point is directly led down to the double-split cable terminal head 9 after passing through the tension insulator string 1 hung on the overhead line side, and is converted into a cable 14 through the cable terminal head 9 and led down from the terminal platform; it is transitioned into two double-split down conductors 3 after passing through a four-split jumper spacer 7; the double-split down conductor 3 uses a double-split jumper spacer 8. The above three-layer down conductor structure solves the problem of the four-split conductor being difficult to lead down from the cable terminal tower, and can effectively realize the straight and smooth transition of the down conductor between the overhead line and the double-split cable terminal head.

[0024] Example 2

[0025] The double-circuit cable terminal tower is also provided with a downlead support. The conductor at the upper conductor crossarm hanging point passes through the tension insulator string 1 hung on the overhead line side and is jumped to the cable side by a jumper string 2, and is led down to the double-jointed cable terminal head 9 through the middle conductor crossarm, the lower conductor crossarm, and the double crossarm support insulator 6 arranged on the cable side of the downlead support; the conductor at the middle conductor crossarm hanging point passes through the tension insulator string 1 hung on the overhead line side and jumps to the suspended tension string 5 suspended on the side of the middle crossarm, and is led down to the double-jointed cable terminal head 9 through the lower conductor crossarm and the double crossarm support insulator 6 arranged on the side of the downlead support; the conductor at the lower conductor crossarm hanging point passes through the tension insulator string 1 hung on the overhead line side and is led down to the double-jointed cable terminal head 9 through the double crossarm support insulator 6 arranged on the overhead line side by the downlead support, and the double crossarm support insulator 6 arranged on the overhead line side by the downlead support is arranged horizontally in parallel. When the total height of the double-circuit cable terminal tower is relatively high, adding a downconductor support can make the conductor downconductor structure more stable.

[0026] like Figure 5As shown, on the cable terminal platform, the double-split down conductor 3 is connected to the cable terminal head 9 through a double-conductor copper-aluminum transition device clamp 12, which can achieve reliable connection between two different material conductors, while reducing the adverse effects caused by material differences, and ensuring the stable transmission of current between conductors of different materials. The double-split down conductor 3 is connected to the arrester drain wire 4 through a double-conductor T-type clamp 11. The double-conductor T-type clamp 11 is a T-shaped structure, which can achieve reliable connection between different conductors, ensure the smooth transition of current between different lines, play a key branching and connecting role in electrical connection, and ensure the integrity of the line and the stability of current transmission. The arrester drain wire 4 is connected to the arrester 10 through a copper-aluminum transition device clamp 13 to ensure safe and reliable transition between copper and aluminum in electrical connection, prevent problems such as poor contact, heating or corrosion caused by improper connection, and ensure the normal operation of the power system.

[0027] like Figure 6 As shown, when the phase sequence of the double-circuit overhead line is arranged from top to bottom as A1, B1, C1 and C2, B2, A2, the cable terminal platforms arranged on both sides of the terminal tower from the overhead line side to the cable side belong to C1, B1, A1 phases and A2, B2, C2 phases, respectively. The two cable terminal heads 9 of the double-spliced ​​cable on each platform are arranged perpendicular to the direction of the overhead line, and a lightning arrester 10 is arranged between the two cable terminal heads 9; the down conductor 3 is converted into a double-spliced ​​cable 14 via the cable terminal head 9.

[0028] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A double-circuit tower overhead line is converted into a double-cable downlead structure, characterized in that: include: A double-circuit cable terminal tower, wherein the double-circuit cable terminal tower is provided with a ground wire cross arm and an upper conductor cross arm, a middle conductor cross arm, and a lower conductor cross arm in sequence from top to bottom, and a conductor hanging point is provided on both sides of each conductor cross arm to form a double circuit with a total of six conductor hanging points; The conductor at the upper conductor cross arm hanging point is led down to the double-jointed cable terminal head (9) through a tension insulator string (1), and then sequentially through the middle conductor cross arm and the double cross arm support insulator (6) provided on the lower conductor cross arm; The conductor at the middle conductor cross arm hanging point is led down to the double-jointed cable terminal head (9) through a tension insulator string (1) and then through a double cross arm support insulator (6) arranged on the lower conductor cross arm; The conductor at the lower conductor cross arm hanging point is directly led down to the double-jointed cable terminal head (9) after passing through a tension insulator string (1).

2. A double-circuit tower overhead line converted into a double-cable downlead structure according to claim 1, characterized in that: A cable terminal platform is arranged for each phase conductor along the direction of the overhead line, and two cable terminal heads (9) of a double-spliced ​​cable are arranged on each cable terminal platform perpendicular to the direction of the overhead line.

3. A double-circuit tower overhead line converted into a double-cable downlead structure according to claim 1, characterized in that: It also includes a lightning arrester (10), which is arranged between two cable terminal heads, and the down conductor (3) is converted into a double-spliced ​​cable (14) via the cable terminal heads (9).

4. A double-circuit tower overhead line converted into a double-cable downlead structure according to claim 1, characterized in that: Double cross-arm type support insulators (6) are respectively arranged on the cable side of the middle conductor cross arm and the lower conductor cross arm, and the double cross-arm type support insulators (6) are arranged horizontally in parallel; The conductor at the upper conductor cross arm hanging point is transformed from four splits into two double split down conductors (3) after passing through a four-split jumper spacer (7); the two double split down conductors (3) are respectively led down through the double cross arm support insulators of the middle conductor cross arm and the lower conductor cross arm, and connected to the cable terminal head (9).

5. A double-circuit tower overhead line converted into a double-cable downlead structure according to claim 4, characterized in that: A jumper string (2) is provided on the double-split down conductor (3) at the lead-out point of the four-split jumper spacer bar (7).

6. A double-circuit tower overhead line converted into a double-cable downlead structure according to claim 1, characterized in that: The conductor at the middle conductor cross arm hanging point is transformed from four splits into two double split down conductors (3) after passing through a four split jumper spacer (7); the two double split down conductors (3) are respectively led down through the double cross arm support insulators (6) of the lower conductor cross arm and connected to the cable terminal head (9).

7. A double-circuit tower overhead line converted into a double-cable downlead structure according to claim 6, characterized in that: At the middle-layer conductor cross arm hanging point, a suspended tension string (5) is provided on the double-split down conductor (3) at the lead-out point of the four-split jumper spacer (7).

8. The double-circuit tower overhead line converted into a double-cable downlead structure according to claim 1, characterized in that: The conductor at the lower conductor cross arm hanging point is transformed from four splits into two double split down conductors (3) after passing through a four split jumper spacer (7), and then connected to a cable terminal head (9).

9. A double-circuit tower overhead line converted into a double-cable downlead structure according to claim 2, characterized in that: Each double-split down conductor (3) is connected to one of the cable terminal heads (9) using a double-conductor copper-aluminum transition device clamp (12), and each double-split down conductor (3) is connected to the arrester drainage wire (4) via a double-conductor T-type clamp (11).

10. A double-circuit tower overhead line converted into a double-cable downlead structure according to claim 3, characterized in that: The lightning arrester (10) is connected to the lightning arrester drain wire (4) via a copper-aluminum transition device clamp (13).

11. A double-circuit tower overhead line converted into a double-cable downlead structure according to claim 1, characterized in that: A downconductor support is provided at the lower part of the lower conductor cross arm, and double cross arm type support insulators (6) are provided on both sides of the downconductor support, wherein the double cross arm type support insulators (6) of the downconductor support are arranged in parallel with the double cross arm type support insulators (6) of the middle conductor cross arm and the lower conductor cross arm; The conductor at the upper conductor cross arm hanging point is led down to the double-jointed cable terminal head (9) via a tension insulator string (1), a double cross arm support insulator (6) of the middle conductor cross arm, a double cross arm support insulator (6) of the lower conductor cross arm, and a double cross arm support insulator (6) of the down conductor support. The conductor at the middle conductor cross arm hanging point is led down to the double-jointed cable terminal head (9) via a tension insulator string (1), a double cross arm support insulator (6) of the lower cross arm, and a double cross arm support insulator (6) of the down conductor support; The conductor at the lower conductor cross-arm hanging point is led down to the double-jointed cable terminal head (9) via a tension insulator string (1) and a double cross-arm support insulator (6) of a down-lead support.

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