CN207813168U - Singly cut-off π sections towers in double loop - Google Patents

Abstract

The utility model discloses a double-circuit single-break π-type iron tower; the technical problem to be solved is to solve the technical problems that the existing break form is easy to form a triangular zone, resulting in a large occupied area, an increase in the number of poles and towers, and an increase in investment cost. The technical solution adopted: a double-circuit single-break π-shaped iron tower, including a tower and a cross-arm arranged on the tower; the cross-arms are arranged at intervals from the top of the tower downwards: the first cross-arm and the second cross-arm, The first π-connected cross-arm is arranged horizontally at the free end of the second cross-arm; the third cross-arm and the fourth cross-arm are horizontally arranged at the free end of the fourth cross-arm; the second π-connected cross-arm is horizontally arranged; the fifth cross-arm and the fourth cross-arm For the six cross-arms, the third π-connected cross-arm is arranged horizontally at the free end of the sixth cross-arm; for the seventh and eighth cross-arms, the fourth π-connected cross-arm is horizontally arranged at the free end of the eighth cross-arm. Advantages, this iron tower can break the line that can only be completed by three base branch towers, and only needs one base iron tower to complete the break line.

Description

Double circuit single break π-type iron tower

technical field

The utility model designs a double-circuit single-break π-shaped iron tower, which belongs to the field of electric equipment.

Background technique

With the rapid development of the economy, the demand for electricity in various places has increased significantly, and high-voltage lines have become more and more dense. Affected by power system planning requirements, in order to reduce line corridors and save land resources, substation sites are usually selected close to existing lines to facilitate access to substations after existing lines are disconnected. Conventional double-circuit transmission lines are disconnected on one side When it is necessary to use three-base double-circuit branch towers to complete the breaking line, this breaking form is easy to form a triangular zone, resulting in a larger floor area, an increase in the number of poles and towers, and an increase in investment costs.

Utility model content

The technical problem to be solved by the utility model is: when the conventional double-circuit transmission line mentioned in the background technology is broken on one side, it is necessary to use a three-base branch tower to complete the breaking line. This breaking type is easy to form a triangular zone, causing Larger occupied area, increased number of poles and towers, and technical problems of increased investment costs.

The purpose of this utility model is to propose a double-circuit single-break π-type iron tower. The use of this double-circuit single-break π-type iron tower can make the breaking line completed by three-base double-circuit branch towers pass through a base iron tower. It can be realized; thereby achieving the purpose of reducing the use of branch towers, reducing land occupation, and saving engineering investment.

In order to solve the problems of the technologies described above, the technical solution adopted in the utility model is:

A double-circuit single-break π-type iron tower, including a tower, and also includes a cross arm arranged on the tower; the cross arms are arranged at intervals from the top of the tower downwards:

The first cross-arm and the second cross-arm, the first cross-arm and the second cross-arm are all arranged on the top of the tower and are located on both sides of the tower, the first cross-arm and the second cross-arm are ground wire cross-arms, The first cross-arm and the second cross-arm are located in the same plane; the upper surface of the first cross-arm is flush with the horizontal plane, the orthographic projection of the first cross-arm is a right triangle, the projection of the first cross-arm on the horizontal plane is a trapezoid, The cross-section of the first cross-arm is rectangular; the upper surface of the second cross-arm is flush with the horizontal plane, the orthographic projection of the second cross-arm is a right triangle, the projection of the second cross-arm on the horizontal plane is trapezoidal, and the cross-section of the second cross-arm is Rectangular; set the first π-connected cross-arm horizontally at the free end of the second cross-arm, the first π-connected cross-arm is perpendicular to the second cross-arm; the orthographic projection of the first π-connected cross-arm is rectangular, and the first π-connected cross-arm The projection on the horizontal plane is rectangular, and the section of the first π connected to the cross arm is rectangular;

The third cross-arm and the fourth cross-arm, the third cross-arm and the fourth cross-arm are set on the tower and are located below the first cross-arm and the second cross-arm, the third cross-arm and the fourth cross-arm are located on the tower On both sides of the frame, the third cross-arm and the fourth cross-arm are upper wire cross-arms, and the third cross-arm and the fourth cross-arm are located in the same plane; the lower surface of the third cross-arm is flush with the horizontal plane, and the third cross-arm The orthographic projection of the arm is a right triangle, the projection of the third arm on the horizontal plane is rectangular, and the section of the third arm is rectangular; the lower surface of the fourth arm is flush with the horizontal plane, and the orthographic projection of the fourth arm is at right angles Triangular, the projection of the fourth cross-arm on the horizontal plane is rectangular, and the cross-section of the fourth cross-arm is rectangular; the second π-connected cross-arm is horizontally set at the free end of the fourth cross-arm, and the second π-connected cross-arm and the fourth cross-arm The shoulder is vertical; the orthographic projection of the second π connected to the cross arm is rectangular, the projection of the second π connected to the cross arm on the horizontal plane is rectangular, and the cross section of the second π connected to the cross arm is rectangular;

The fifth cross arm and the sixth cross arm, the fifth cross arm and the sixth cross arm are all set on the tower and located below the third cross arm and the fourth cross arm, and the fifth cross arm and the sixth cross arm are located on the tower On both sides of the frame, the fifth cross-arm and the sixth cross-arm are center conductor cross-arms, and the fifth cross-arm and the sixth cross-arm are located in the same plane; the lower surface of the fifth cross-arm is flush with the horizontal plane, and the fifth cross-arm The orthographic projection of the arm is a right triangle, the projection of the fifth arm on the horizontal plane is rectangular, and the section of the fifth arm is rectangular; the lower surface of the sixth arm is flush with the horizontal plane, and the orthographic projection of the sixth arm is at right angles Triangular, the projection of the sixth cross arm on the horizontal plane is rectangular, and the cross-section of the sixth cross arm is rectangular; the third π-connected cross-arm is horizontally set at the free end of the sixth cross-arm, and the third π-connected cross-arm and the sixth cross-arm The shoulder is vertical; the orthographic projection of the third π connected to the cross arm is rectangular, the projection of the third π connected to the cross arm on the horizontal plane is rectangular, and the cross section of the third π connected to the cross arm is rectangular;

The seventh cross-arm and the eighth cross-arm, the seventh cross-arm and the eighth cross-arm are set on the tower and are located below the fifth and sixth cross-arms, and the seventh and eighth cross-arms are located on the tower Both sides of the frame, the seventh cross-arm and the eighth cross-arm are the lower conductor cross-arms, the seventh cross-arm and the eighth cross-arm are located in the same plane; the lower surface of the seventh cross-arm is flush with the horizontal plane, and the seventh cross-arm The orthographic projection of the arm is a right triangle, the projection of the seventh arm on the horizontal plane is trapezoidal, and the section of the seventh arm is rectangular; the lower surface of the eighth arm is flush with the horizontal plane, and the orthographic projection of the eighth arm is at right angles Triangular, the projection of the eighth cross-arm on the horizontal plane is trapezoidal, and the cross-section of the eighth cross-arm is rectangular; the fourth π-connected cross-arm is horizontally set at the free end of the eighth cross-arm, and the fourth π-connected cross-arm and the eighth cross-arm The shoulder is vertical; the orthographic projection of the fourth π connected to the cross arm is rectangular, the projection of the fourth π connected to the cross arm on the horizontal plane is rectangular, and the cross section of the fourth π connected to the cross arm is rectangular;

The free ends of all cross-arms are hanging points, and the wires are connected through insulator strings;

The first π is connected to the hanging point on the cross arm, and the wire is hung on the insulator string to form a "π type";

The second π is connected to the hanging point on the cross arm, and the wire is hung through the insulator string to form a "π type";

The third π is connected to the hanging point on the cross arm, and after the wire is hung on the insulator string, a "π type" is formed;

The fourth π connects the wire hanging point on the cross arm to form a "π type" after hanging the wire through the insulator string.

In the utility model, all the cross arms are connected with the iron tower body by bolts to form a complete steel truss iron tower. The end of the cross arm is a hanging point, which is connected to the wire through an insulator string. The above first π is connected to the hanging point on the cross arm through an insulator After the wires are hung in series, a "π-type" is formed; the second π is connected to the hanging point on the cross-arm through the insulator and the wire is hung in series to form a "π-type"; the third π is connected to the hanging point on the cross-arm through the insulator. After the wires are hung in series, a "π type" is formed; the fourth π connects the wire hanging point on the cross arm to form a "π type" after the insulator strings are hung with wires.

As an improvement to the technical solution of the utility model, the cross arm is an angle steel truss structure. In order to improve the structural strength of the cross arm and reduce the overall weight of the cross arm, the cross arm is designed as a triangular truss structure. The triangular structure has high stability and light weight. The cross arm and tower body are made of hot-dip galvanized angle steel.

As an improvement to the technical solution of the utility model, all cross-arms are connected with the tower body of the tower through bolts.

According to the national standard "Code for Design of 110kV～750kV Overhead Transmission Lines" (GB 50545-2010), in order to ensure the safe distance between each other, the crossing distance between 220kV power lines and 220kV power lines is 4m, and the crossing distance between 220kV power lines and 110kV power lines The distance is 3m.

To the improvement of the technical solution of the utility model, the length of the first cross arm and the second cross arm is 6.5m, and the distance between the first cross arm and the second cross arm and the third cross arm and the fourth cross arm is 4.5m .

To the improvement of the technical solution of the utility model, the lengths of the third cross arm and the fourth cross arm are both 5.3m, and the distance between the third cross arm and the fourth cross arm and the fifth cross arm and the sixth cross arm is 6.7m .

To the improvement of the technical solution of the utility model, the length of the fifth cross arm and the sixth cross arm is 6.5m, and the distance between the fifth cross arm and the sixth cross arm and the seventh cross arm and the eighth cross arm is 6.3m .

As an improvement to the technical solution of the utility model, the lengths of the seventh cross arm and the eighth cross arm are both 6.0m.

To the improvement of the technical solution of the utility model, the length of the first π connection cross arm is 5.6m, and the lengths of the second π connection cross arm, the third π connection cross arm and the fourth π connection cross arm are equal to 6.4m. Since the length of the first π-connected cross-arm is 5.6m, the lengths of the second π-connected cross-arm, the third π-connected cross-arm and the fourth π-connected cross-arm are equal to 6.4m, the arrangement of the wires is changed from vertical to When the arrangement becomes a horizontal arrangement, the phase-to-phase distance of the conductors cannot meet the specification requirements. Therefore, the utility model is not used as a terminal tower, but only as a breaking tower in the middle of the line. When the conductors are arranged in a vertical arrangement, the phase-to-phase distance can meet the specification requirements. .

Compared with the prior art, the utility model has the beneficial effects of:

The iron tower of the utility model can break the line that can only be completed by three base branch towers, and only needs one base iron tower to complete the break line. And the iron tower voltage class disclosed by the utility model is 220kV.

The iron tower of the utility model satisfies the demand for increasingly frequent double-circuit single-break engineering construction of the power transmission line system.

Description of drawings

Figure 1 is a three-dimensional diagram of a double-circuit single-break π-shaped iron tower.

Fig. 2 is a front view of a double-circuit single-break π-type iron tower.

Fig. 3 is an installation diagram of the first cross arm, the second cross arm and the first π-connected cross arm.

Fig. 4 is an installation diagram of the third cross arm, the fourth cross arm and the second π-connected cross arm.

Fig. 5 is an installation diagram of the fifth cross arm, the sixth cross arm and the third π-connected cross arm.

Fig. 6 is an installation diagram of the seventh cross arm, the eighth cross arm and the fourth π-connected cross arm.

Fig. 7 is a schematic diagram of double-circuit unbroken lines.

Fig. 8 is a schematic diagram of a double-circuit single-break π connection circuit.

Detailed ways

The technical solutions of the utility model are described in detail below, but the protection scope of the utility model is not limited to the embodiments.

In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model will be further described in detail below in conjunction with the accompanying drawings 1-8 and the embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model, and are not intended to limit the utility model.

Example:

As shown in FIG. 1 , the double-circuit single-break π-type iron tower in this embodiment includes a tower 9 and a cross arm arranged on the tower 9 .

As shown in Figure 1, the tower frame 9 in the present embodiment, the tower body of the tower frame shrinks gradually from its bottom end to the upper end, is the design of variable slope, adopts the tower frame of variable slope design to be the conventional technology in the prior art. The opening size of the bottom end of the tower body of the tower frame in this embodiment is 9.2m to 11.8m, and the opening size of the tower body top end of the tower frame is 2.2m. The tower body angle steel truss structure of the tower. The tower 9 in this embodiment is similar to a quadrangular pyramid and can ensure the stability of the tower structure.

As shown in Figure 1, the cross arm in this embodiment is an angle steel truss structure. In order to improve the structural strength of the cross arm and reduce the overall weight of the cross arm, the cross arm is designed as a triangular truss structure. The triangular structure has high stability and light weight. The cross arm and tower body are made of hot-dip galvanized angle steel.

As shown in Figures 1 and 2, all the cross arms in this embodiment are connected to the iron tower body by bolts to form a complete steel truss iron tower. The wire hanging point on the pole 10 forms a "π type" after the wire is hung on the insulator string; Connect the wire hanging point on the cross arm 12 and then form "π type" after hanging the wire through the insulator string;

Line breaking is a common construction technology form of high-voltage AC transmission lines in power engineering, including single-circuit breaking to form double circuits; kind of form.

As shown in Figure 7, it is a schematic diagram of the double circuit unbroken circuit, in which 14 is a cross arm, 15 is a tension insulator, 16 is the first circuit, and 17 is the second circuit.

The double-circuit single-break π-type iron tower means that one of the two circuits is connected to the cross-arm through the π on the iron tower to form a new double-circuit, and a total of three circuits share a base with the other unbroken circuit on the iron tower. The shape of the iron tower is like a "π" character, hence the name.

Figure 8 is a schematic diagram of a double-circuit single-break π connection circuit. Among the figure, 14 is a cross arm, 15 is a tension insulator, 16 is a first circuit, 17 is a second circuit, 18 is a π connection cross arm, and 19 is a third circuit.

As shown in Figures 1 and 2, the cross arms are arranged at intervals downward from the top of the tower 9:

As shown in Figures 2 and 3, the first cross arm 1 and the second cross arm 2, the first cross arm 1 and the second cross arm 2 are all arranged on the top of the tower 9 by bolts to be located on both sides of the tower 9, The first cross-arm 1 and the second cross-arm 2 are both ground wire cross-arms, and the first cross-arm 1 and the second cross-arm 2 are located in the same plane; the upper surface of the first cross-arm 1 is flush with the horizontal plane, and the first cross-arm The orthographic projection of the cross arm 1 is a right triangle, the projection of the first cross arm 1 on the horizontal plane is trapezoidal, and the cross section of the first cross arm 1 is rectangular; the upper surface of the second cross arm 2 is flush with the horizontal plane, and the second cross arm 2 The orthographic projection of is a right triangle, the projection of the second cross-arm 2 on the horizontal plane is trapezoidal, and the cross-section of the second cross-arm 2 is a rectangle; A π-connected cross-arm 10 is perpendicular to the second cross-arm 2; the orthographic projection of the first π-connected cross-arm 10 is rectangular, the projection of the first π-connected cross-arm 10 on the horizontal plane is rectangular, and the projection of the first π-connected cross-arm 10 is rectangular. The section is rectangular.

The first π connects the wire hanging point on the cross arm 10 to form a "π type" after the insulator string hangs up the wire.

As shown in Figures 2 and 4, the third cross arm 3 and the fourth cross arm 4, the third cross arm 3 and the fourth cross arm 4 are all set on the tower 9 by bolts and are located on the first cross arm 1 and the second cross arm. Below the cross arm 2, the third cross arm 3 and the fourth cross arm 4 are located on both sides of the tower 9, the third cross arm 3 and the fourth cross arm 4 are all upper wire cross arms, the third cross arm 3 and the fourth cross arm The four cross-arms 4 are located in the same plane; the lower surface of the third cross-arm 3 is flush with the horizontal plane, the orthographic projection of the third cross-arm 3 is a right triangle, the projection of the third cross-arm 3 on the horizontal plane is rectangular, and the third cross-arm 3 The cross-section of bearer 3 is rectangular; the lower surface of the fourth cross-arm 4 is flush with the horizontal plane, the orthographic projection of the fourth cross-arm 4 is a right triangle, the projection of the fourth cross-arm 4 on the horizontal plane is rectangular, and the fourth cross-arm 4 The cross-section is rectangular; the free end of the fourth cross-arm 4 is horizontally provided with a second π-connected cross-arm 11, and the second π-connected cross-arm 11 is perpendicular to the fourth cross-arm 4; the orthographic projection of the second π-connected cross-arm 11 is Rectangular, the projection of the second π-connected cross-arm 11 on the horizontal plane is rectangular, and the cross-section of the second π-connected cross-arm 11 is rectangular.

The second π connects the wire hanging point on the cross arm 11 to form a "π type" after hanging the wire through the insulator string.

As shown in Figures 2 and 5, the fifth cross arm 5 and the sixth cross arm 6, the fifth cross arm 5 and the sixth cross arm 6 are all set on the tower 9 by bolts and are located at the third cross arm 3 and the fourth cross arm. Below the cross arm 4, the fifth cross arm 5 and the sixth cross arm 6 are located on both sides of the tower 9, the fifth cross arm 5 and the sixth cross arm 6 are all center conductor cross arms, the fifth cross arm 5 and the sixth cross arm The six cross-arms 6 are located in the same plane; the lower surface of the fifth cross-arm 5 is flush with the horizontal plane, the orthographic projection of the fifth cross-arm 5 is a right triangle, the projection of the fifth cross-arm 5 on the horizontal plane is rectangular, and the fifth cross-arm 5 The cross-section of bearer 5 is rectangular; the lower surface of the sixth cross-arm 6 is flush with the horizontal plane, the orthographic projection of the sixth cross-arm 6 is a right triangle, and the projection of the sixth cross-arm 6 on the horizontal plane is rectangular, and the sixth cross-arm 6 The cross-section is rectangular; the third π cross-arm 12 is horizontally set at the free end of the sixth cross-arm 6, and the third π-connected cross-arm 12 is perpendicular to the sixth cross-arm 6; the orthographic projection of the third π-connected cross-arm 12 is Rectangular, the projection of the third π-connected cross-arm 12 on the horizontal plane is rectangular, and the cross-section of the third π-connected cross-arm 12 is rectangular.

The third π connects the wire hanging point on the cross arm 12 to form a "π type" after hanging the wire through the insulator string.

As shown in Figures 2 and 6, the seventh cross-arm 7 and the eighth cross-arm 8, the seventh cross-arm 7 and the eighth cross-arm 8 are all set on the tower 9 by bolts and are located at the fifth cross-arm 5 and the sixth cross-arm. Below the cross-arm 6, the seventh cross-arm 7 and the eighth cross-arm 8 are located on both sides of the tower 9, the seventh cross-arm 7 and the eighth cross-arm 8 are all down-conducting cross-arms, Eight cross-arms 8 are located in the same plane; the lower surface of the seventh cross-arm 7 is flush with the horizontal plane, the orthographic projection of the seventh cross-arm 7 is a right triangle, the projection of the seventh cross-arm 7 on the horizontal plane is trapezoidal, and the seventh cross-arm 7 The cross-section of bearer 7 is rectangular; the lower surface of the eighth cross-arm 8 is flush with the horizontal plane, the orthographic projection of the eighth cross-arm 8 is a right triangle, the projection of the eighth cross-arm 8 on the horizontal plane is trapezoidal, and the eighth cross-arm 8 The cross-section is rectangular; the fourth π cross-arm 13 is horizontally set at the free end of the eighth cross-arm 8, and the fourth π-connected cross-arm 13 is perpendicular to the eighth cross-arm 8; the orthographic projection of the fourth π-connected cross-arm 13 is Rectangular, the projection of the fourth π-connected cross-arm 13 on the horizontal plane is rectangular, and the cross-section of the fourth π-connected cross-arm 13 is rectangular.

The fourth π connects the wire hanging point on the cross arm 13 to form a "π type" after the insulator string hangs up the wire.

According to the national standard "Code for Design of 110kV～750kV Overhead Transmission Lines" GB 50545-2010, in order to ensure the safe distance between each other, the crossing distance between the 220kV power line and the 220kV power line is 4m, and the crossing distance between the 220kV power line and the 110kV power line is 3m.

As shown in Figure 2, the lengths of the first cross arm 1 and the second cross arm 2 are both 6.5m, the distance between the first cross arm 1 and the second cross arm 2 and the third cross arm 3 and the fourth cross arm 4 The spacing is 4.5m. The lengths of the third cross arm 3 and the fourth cross arm 4 are both 5.3m, and the distance between the third cross arm 3 and the fourth cross arm 4 and the fifth cross arm 5 and the sixth cross arm 6 is 6.7m. The length of the fifth cross arm 5 and the sixth cross arm 6 is 6.5m, and the distance between the fifth cross arm 5 and the sixth cross arm 6 and the seventh cross arm 7 and the eighth cross arm 8 is 6.3m. The lengths of the seventh cross arm 7 and the eighth cross arm 8 are both 6.0 m.

As shown in Fig. 2, the length of the first π-connected cross-arm 10 is 5.6m, the lengths of the second π-connected cross-arm 11, the third π-connected cross-arm 12 and the fourth π-connected cross-arm 13 are equal to 6.4m. Because the length of the first π connection cross arm 10 is 5.6m, the lengths of the second π connection cross arm 11, the third π connection cross arm 12 and the fourth π connection cross arm 13 are equal to 6.4m, the wire arrangement is carried out When the line stalls are arranged from vertical to horizontal, the interphase distance of the conductors cannot meet the requirements of the specification. Therefore, the utility model is not used as a terminal tower, but only as a breaking tower in the middle of the line. The arrangement of the conductors is the vertical distance between phases meet specification requirements.

As stated above, although the invention has been shown and described with reference to certain preferred embodiments, this should not be construed as limiting the invention itself. Various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (8)

1. A double-circuit single-break π-type iron tower, comprising a tower (9), is characterized in that, also includes a cross-arm arranged on the tower (9); the cross-arm is spaced downward from the top of the tower (9) layout: The first cross arm (1) and the second cross arm (2), the first cross arm (1) and the second cross arm (2) are all arranged on the top of the tower (9) side, the first cross-arm (1) and the second cross-arm (2) are ground cross-arms, and the first cross-arm (1) and the second cross-arm (2) are located in the same plane; the first cross-arm (1 ) is flush with the horizontal plane, the orthographic projection of the first cross-arm (1) is a right triangle, the projection of the first cross-arm (1) on the horizontal plane is trapezoidal, and the cross-section of the first cross-arm (1) is rectangular; The upper surface of the second cross-arm (2) is flush with the horizontal plane, the orthographic projection of the second cross-arm (2) is a right triangle, the projection of the second cross-arm (2) on the horizontal plane is trapezoidal, and the second cross-arm (2) ) is rectangular in section; the first π connection cross arm (10) is horizontally set at the free end of the second cross arm (2), and the first π connection cross arm (10) is perpendicular to the second cross arm (2); the first The orthographic projection of the π-connected cross-arm (10) is rectangular, the projection of the first π-connected cross-arm (10) on the horizontal plane is rectangular, and the cross-section of the first π-connected cross-arm (10) is rectangular; The third cross-arm (3) and the fourth cross-arm (4), the third cross-arm (3) and the fourth cross-arm (4) are all arranged on the tower (9) and are positioned at the first cross-arm (1) and the fourth cross-arm (4). Below the second cross arm (2), the third cross arm (3) and the fourth cross arm (4) are located on both sides of the tower (9), and the third cross arm (3) and the fourth cross arm (4) Both are upper conductor cross arms, the third cross arm (3) and the fourth cross arm (4) are located in the same plane; the lower surface of the third cross arm (3) is flush with the horizontal plane, and the third cross arm (3) The orthographic projection is a right triangle, the projection of the third cross arm (3) on the horizontal plane is rectangular, and the section of the third cross arm (3) is rectangular; the lower surface of the fourth cross arm (4) is flush with the horizontal plane, and the fourth The orthographic projection of the cross-arm (4) is a right triangle, the projection of the fourth cross-arm (4) on the horizontal plane is rectangular, and the section of the fourth cross-arm (4) is rectangular; at the free end of the fourth cross-arm (4) The second π connects the cross arm (11) horizontally, the second π connects the cross arm (11) and the fourth cross arm (4) is vertical; The projection of the cross arm (11) on the horizontal plane is rectangular, and the cross section of the second π connection cross arm (11) is rectangular; The fifth cross arm (5) and the sixth cross arm (6), the fifth cross arm (5) and the sixth cross arm (6) are all arranged on the tower (9) and are located at the third cross arm (3) and Below the fourth cross arm (4), the fifth cross arm (5) and the sixth cross arm (6) are located on both sides of the tower (9), and the fifth cross arm (5) and the sixth cross arm (6) Both are center conductor cross arms, the fifth cross arm (5) and the sixth cross arm (6) are located in the same plane; the lower surface of the fifth cross arm (5) is flush with the horizontal plane, and the fifth cross arm (5) The orthographic projection is a right triangle, the projection of the fifth cross arm (5) on the horizontal plane is rectangular, and the section of the fifth cross arm (5) is rectangular; the lower surface of the sixth cross arm (6) is flush with the horizontal plane, and the sixth The orthographic projection of the cross-arm (6) is a right triangle, the projection of the sixth cross-arm (6) on the horizontal plane is rectangular, and the section of the sixth cross-arm (6) is rectangular; at the free end of the sixth cross-arm (6) The third π is connected horizontally to the cross arm (12), and the third π is connected to the cross arm (12) to be perpendicular to the sixth cross arm (6); the orthographic projection of the third π to the cross arm (12) is rectangular, and the third π is connected to The projection of the cross arm (12) on the horizontal plane is rectangular, and the section of the third π connected cross arm (12) is rectangular; The seventh cross-arm (7) and the eighth cross-arm (8), the seventh cross-arm (7) and the eighth cross-arm (8) are all arranged on the tower (9) and are positioned at the fifth cross-arm (5) and Below the sixth cross arm (6), the seventh cross arm (7) and the eighth cross arm (8) are located on both sides of the tower (9), and the seventh cross arm (7) and the eighth cross arm (8) Both are lower conductor cross arms, the seventh cross arm (7) and the eighth cross arm (8) are located in the same plane; the lower surface of the seventh cross arm (7) is flush with the horizontal plane, and the seventh cross arm (7) The orthographic projection is a right triangle, the projection of the seventh cross arm (7) on the horizontal plane is trapezoidal, and the cross section of the seventh cross arm (7) is rectangular; the lower surface of the eighth cross arm (8) is flush with the horizontal plane, and the eighth The orthographic projection of the cross-arm (8) is a right triangle, the projection of the eighth cross-arm (8) on the horizontal plane is trapezoidal, and the section of the eighth cross-arm (8) is rectangular; at the free end of the eighth cross-arm (8) The fourth π connects the cross arm (13) horizontally, the fourth π connects the cross arm (13) and the eighth cross arm (8) vertically; the orthographic projection of the fourth π connects the cross arm (13) is rectangular, and the fourth π connects The projection of the cross arm (13) on the horizontal plane is rectangular, and the cross section of the fourth π connection cross arm (13) is rectangular; The free ends of all cross-arms are hanging points, and the wires are connected through insulator strings; The first π connects the wire hanging point on the cross arm (10) to form a "π type" after the insulator string hangs the wire; The second π connects the wire hanging point on the cross arm (11) to form a "π type" after hanging the wire through the insulator string; The third π connects the wire hanging point on the cross arm (12) to form a "π type" after hanging the wire through the insulator string; The 4th π connects the line hanging point on the cross arm (13) and then forms " π type " after hanging up lead by insulator string. 2. The double-circuit single-break π-type iron tower according to claim 1, wherein the cross-arm is an angle steel truss structure. 3. The double-circuit single-break π-type iron tower as claimed in claim 1, wherein all cross-arms are connected to the body of the tower (9) by bolts. 4. double-circuit single break π type iron tower as claimed in claim 1, is characterized in that, the length of the first cross arm (1) and the second cross arm (2) is 6.5m, the first cross arm (1 ) and the distance between the second cross-arm (2) and the third cross-arm (3) and the fourth cross-arm (4) is 4.5m. 5. double-circuit single break π type iron tower as claimed in claim 1, is characterized in that, the length of the 3rd cross arm (3) and the 4th cross arm (4) is 5.3m, the 3rd cross arm (3) ) and the distance between the fourth cross arm (4) and the fifth cross arm (5) and the sixth cross arm (6) is 6.7m. 6. double-circuit single break π type iron tower as claimed in claim 1, is characterized in that, the length of the 5th cross arm (5) and the 6th cross arm (6) is 6.5m, the 5th cross arm (5) ) and the distance between the sixth cross arm (6) and the seventh cross arm (7) and the eighth cross arm (8) is 6.3m. 7. The double-circuit single-break π-type iron tower according to claim 1, characterized in that the lengths of the seventh cross arm (7) and the eighth cross arm (8) are both 6.0m. 8. The double-circuit single-break π-type iron tower as claimed in claim 1, characterized in that, the first π connects the length of the cross arm (10) to 5.6m, the second π connects the cross arm (11), the third π Connect cross-arm (12) and the 4th π and connect the length equal of cross-arm (13) and be 6.4m.