CN214532233U - Power transmission tower - Google Patents

Abstract

The application discloses a power transmission tower, which comprises a tower body and a cross arm fixed on the tower body, wherein the cross arm comprises at least one cross arm group, and the cross arm group comprises a metal cross arm and a composite cross arm; one end of the metal cross arm is connected with the tower body and extends out of the tower body, the other end of the metal cross arm is connected with one end of the composite cross arm, and the other end of the composite cross arm is connected with a conducting wire in a hanging mode. This transmission tower adopts the mode that metal cross arm and compound cross arm combine, has utilized the characteristic that the shorter and bigger intensity of composite member length, has given full play to combined material's intensity advantage and the insulating advantage that self material possessed, and the intensity advantage of metal material self in addition saves and draws the insulator to one side to reduce the cost of transmission tower engineering.

Description

Power transmission tower

Technical Field

The application relates to the field of power transmission insulating equipment, in particular to a power transmission tower.

Background

At present, two types of common cross arms on power transmission towers are pure composite cross arms and pure metal cross arms. The pure composite cross arm type comprises a single column type, a single column single-pull type, a single column three-pull type, a double column single-pull type and a double column double-pull type. The longer the single-column type composite cross arm is, the lower the strength is, and the single-column type composite cross arm can only be applied to the power transmission tower with a smaller voltage grade, and other cross arm types are generally higher in manufacturing cost on the overhead power transmission iron tower. Especially for voltage levels of 110kV and below, the cost of the transmission tower project is increased by adopting the common pure composite cross arm type because the cost of the transmission tower project is not very high at the voltage level. The pure metal cross arm needs to adopt a suspension insulator, which increases the tower height and also causes the cost of the power transmission tower project to increase, so that a new cross arm type needs to be developed to reduce the cost of the power transmission tower project urgently.

SUMMERY OF THE UTILITY MODEL

The utility model aims at the not enough of prior art, the utility model aims at providing a power transmission tower, this power transmission tower adopt the mode that metal cross arm and compound cross arm combine, have utilized the big more characteristic of short intensity the more of composite member length, full play combined material's intensity advantage and the insulating advantage that self material possessed, in addition the intensity advantage of metal material self, save and draw the insulator to one side to reduce the cost of power transmission tower engineering.

In order to achieve the above object, the present invention adopts the following technical means: a power transmission tower comprises a tower body and a cross arm fixed on the tower body, wherein the cross arm comprises at least one cross arm group, and the cross arm group comprises a metal cross arm and a composite cross arm; one end of the metal cross arm is connected with the tower body and extends out of the tower body, the other end of the metal cross arm is connected with one end of the composite cross arm, and the other end of the composite cross arm is connected with a conducting wire in a hanging mode. This transmission tower adopts the mode that metal cross arm and compound cross arm combine, has utilized the characteristic that the shorter and bigger intensity of composite member length, has given full play to combined material's intensity advantage and the insulating advantage that self material possessed, and the intensity advantage of metal material self in addition saves and draws the insulator to one side to reduce the cost of transmission tower engineering. The cross arm comprises at least one cross arm group, and different use requirements can be met.

Preferably, the composite cross arm is a composite post insulator and comprises an inner flange and a core rod, wherein the inner flange is sleeved on the core rod and is connected with the metal cross arm. The composite post insulator has good electrical insulation performance, high strength, and excellent corrosion resistance and durability.

Preferably, the inner flange comprises a first sleeve and a first base, the first sleeve is sleeved on the mandrel, the first base comprises two first risers which are arranged along the axial direction of the mandrel, and the two first risers are parallel to each other and perpendicular to the first sleeve. The flange of this type is simple in structure, easy to manufacture and easy to connect with the metal cross arm.

Preferably, the metal cross arm includes two L type angle steel, and two L type angle steel are the T type setting, and two risers and two L type angle steel of inner flange are fixed with the mutual centre gripping of two L type angle steel. The L-shaped angle steel is easy to obtain, does not need to be specially made, is relatively cheap, has good bending resistance and high strength, and is arranged in a T shape, matched with the inner flange for use and easy to connect. In addition, two risers and two L type angle steel of inner flange mutual centre gripping are fixed including different compound mode, including two riser centre gripping fixed two L type angle steels of inner flange, two risers and two crisscross centre gripping of L type angle steel fixed, can select according to the demand of difference.

Preferably, the metal cross arm is T type angle steel, including first diaphragm and a second riser perpendicular to first diaphragm, and two riser centre gripping of inner flange are fixed the second riser. T type angle steel is overall structure, compares with the integrated configuration of two L type angle steels, and anti bending property is better, and intensity is bigger to can not lead to the unstability of metal cross arm structure because of connecting bolt's inefficacy.

Preferably, there are at least two cross arm sets, and each cross arm set is parallel to each other. In order to meet different use requirements, the cross arm can comprise at least two cross arm groups, the cross arm groups are parallel to each other, and the parallel structure enables the bending resistance and the compression resistance of the cross arm to be higher.

Preferably, when the number of the cross arm groups is at least two, the cross arm further comprises an inner connecting piece, preferably, the inner connecting piece is an angle iron and is connected with at least two metal cross arms. The arrangement of the inner connecting piece can deal with the longitudinal tensile force brought to the cross arm after the wire is hung.

Preferably, when the number of the cross arm groups is at least two, the cross arm further comprises an outer connecting piece, and the ends of the at least two composite cross arms far away from the tower body are connected through the outer connecting piece. The outer connecting piece is connected with at least two cross arm groups, so that the cross arms form an integral structure, and the bending resistance is better.

Preferably, the composite post insulator comprises an outer flange, the outer flange comprises a second sleeve and a second base, the second sleeve is sleeved on the mandrel, the second base is a third vertical plate which is perpendicular to the axial direction of the mandrel, and the length of the third vertical plate is larger than the diameter of the second sleeve. The flange of this type is simple structure, easily preparation, and easily links to each other with outer connecting piece.

Preferably, the outer connecting piece includes two L type angle steel, and two L type angle steel are the T type setting, and the fixed second base of two L type angle steel centre gripping sets up wire connecting device on the outer connecting piece. The L-shaped angle steels are easy to obtain, do not need to be specially made, are relatively cheap, have good bending resistance and high strength, are arranged in a T shape, are matched with the outer flange for use, and are easy to connect.

Preferably, the cross arm is a double-arm cross arm, and the two ends of the metal cross arm are both connected with the composite cross arm. The requirement of hanging wires at two ends of the power transmission tower can be met.

Drawings

Fig. 1 is a partial schematic view of a transmission tower 1000 according to a first embodiment of the present invention;

fig. 2 is a schematic structural diagram of a cross arm 1200 on a transmission tower 1000 according to a first embodiment of the present invention;

fig. 3 is a partial schematic view of a transmission tower 2000 according to a second embodiment of the present invention;

fig. 4 is a schematic structural diagram of a cross arm 2200 on a transmission tower 2000 according to a second embodiment of the present invention;

fig. 5 is a partial schematic view of a transmission tower 3000 according to a third embodiment of the present invention.

Fig. 6 is a partial schematic view of a transmission tower 4000 according to a fourth embodiment of the present invention.

Detailed Description

As required, detailed embodiments of the present invention will be disclosed herein. However, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed manner, including employing various features disclosed herein in connection with which such features may not be explicitly disclosed.

The first embodiment is as follows:

as shown in fig. 1, the present embodiment provides a transmission tower 1000, which includes a tower body 1100 and a cross arm 1200 fixed to the tower body 1100. In this embodiment, the cross arm 1200 includes a cross arm group 1210, the cross arm group 1210 includes a metal cross arm 1220 and a composite cross arm 1230, one end of the metal cross arm 1220 is connected with a tower body angle steel 1110 horizontally arranged on the tower body 1100, and the metal cross arm 1220 extends out of the tower body 1100, the other end of the metal cross arm 1220 is connected with one end of the composite cross arm 1230, and the other end of the composite cross arm 1230 is connected with a wire-hanging hardware string 1260. The power transmission tower 1000 adopts a mode of combining the metal cross arm 1220 and the composite cross arm 1230, utilizes the characteristic that the shorter the length of the composite member is, the higher the strength is, the strength advantage of the composite material and the insulation advantage of the material of the composite member are fully exerted, and in addition, the strength advantage of the metal material is saved, and a cable-stayed insulator is omitted, so that the cost of the power transmission tower engineering is reduced.

In this embodiment, the metal cross-arm 1220 extends outside the tower body 1100. It can be ensured that the shortest composite cross arm 1230 can be used to achieve the maximum mechanical strength, while meeting the standard length and insulation distance of cross arm 1200.

Fig. 1 is combined with fig. 2 to show that, in this embodiment, the composite cross arm 1230 is a composite post insulator, and includes a mandrel 1231 and an inner flange 1240, the inner flange 1240 includes a first sleeve 1241 and a first base 1242, the first sleeve 1241 is sleeved on the mandrel 1231, the first base 1242 includes two first risers 1243 axially disposed along the mandrel 1231, the two first risers 1243 are parallel to each other and perpendicular to the first sleeve 1241, and the two first risers 1243 are provided with a plurality of through holes and connected to the metal cross arm 1220. This type of flange is simple in structure, easy to manufacture, and easy to connect with metal cross arm 1220.

In other embodiments, the composite cross arm may be other composite material components as long as the insulation strength can be ensured. When the composite cross arm is a composite post insulator, the structure of the flange is not limited to the above structure, as long as the flange can be connected to the metal cross arm.

In the present embodiment, the metal cross arm 1220 includes two L-shaped angle steels 1221, and the L-shaped angle steels 1221 include a first limb back 1222 and a second limb back 1223. The two first limb backs 1222 of the two L-shaped angle steels 1221 are arranged in parallel and closely to each other, and the two second limb backs 1223 are located on the same horizontal plane, so that the two L-shaped angle steels 1221 are in a T-shaped structure. The two first risers 1243 of the inner flange 1240 clamp the two first limb backs 1222. The end parts of the two first limb backs 1222 are provided with through holes corresponding to the through holes on the first vertical plates 1243, and the two first vertical plates 1243 are matched with the through holes through bolts to clamp and fix the two first limb backs 1222. L type angle steel 1221 easily acquires, does not need purpose-built, and is comparatively cheap, and anti bending property is good, and intensity is big, and two L type angle steels 1221 are the T type setting, uses with the cooperation of inner flange 1240, easily connects.

In other embodiments, the two first risers of the inner flange can be clamped and fixed with the two L-shaped angle steels in a staggered manner, that is, the two first limbs of the two L-shaped angle steels are arranged in parallel and have a gap, and the gap is used for clamping and fixing one first riser of the inner flange.

In other embodiments, the metal cross arm can also be a T-shaped angle iron, and comprises a first transverse plate and a second vertical plate perpendicular to the first transverse plate, and the two first vertical plates of the inner flange clamp and fix the second vertical plate. T type angle steel is overall structure, compares with the integrated configuration of two L type angle steels, and anti bending performance is better, and intensity is bigger.

In this embodiment, the tower body 1100 includes the tower body angle steel 1110 that two levels set up, and two tower body angle steels 1110 are in same horizontal plane and are parallel to each other and lie in the both sides of tower body 1100, and the middle part of two tower body angle steels 1110 all sets up a plurality of through-holes, and the second limb back 1223 of metal cross arm 1220 corresponds the department with the through-hole position of tower body angle steel 1110 and also sets up a plurality of through-holes for metal cross arm 1220 and tower body angle steel 1110 can pass through bolt fixed connection. The center portion does not necessarily mean the center of the tower angle 1110, and the tower angle 1110 is not connected to another angle at any position.

In this embodiment, the metal cross arm 1220 is perpendicular to the tower angle 1110.

In other embodiments, any other angle may be formed between the metal cross arm and the angle steel of the tower body, as long as the metal cross arm can be connected with the tower body.

In this embodiment, the other end of the composite cross arm 1230 is provided with an outer flange 1250, and the outer flange 1250 is connected with a wire hanging hardware string 1260 for hanging a conducting wire.

In other embodiments, the outer flange may be provided with other wire connecting devices to connect the wires.

In this embodiment, composite cross arm 1230 has a composite post insulator length of no more than 1.1 meters. Because the composite post insulator has a scale effect, the longer the composite post insulator is, the more serious the reduction of the strength of the composite post insulator is, so that the strength advantage of the composite material can be exerted by shortening the composite post insulator. The length of the composite cross arm 1230 is not more than 1.1 m, so that the length required by insulation can be ensured, and the bending strength required by the cross arm 1200 can be ensured.

In other embodiments, the length of the composite cross arm may be other lengths approaching 1.1 meters, as long as the required insulation requirements and bending strength of the cross arm are met.

In this embodiment, the mandrel 1231 is a solid rectangular cross-section mandrel. The bending strength is high and easy to obtain, and special manufacture is not needed.

In other embodiments, the composite post insulator may be a composite post insulator inflated with air or polyurethane, or may be another composite post insulator, and the cross section of the core rod is not limited to a rectangle, a circle, an i-shape, or the like.

In this embodiment, the metal cross arm 1220 and the composite cross arm 1230, the metal cross arm 1220 and the tower 1100, and the outer flange 1250 and the wire-hanging hardware string 1260 are connected by bolts, so that the installation and the replacement are facilitated.

In other embodiments, the components may be connected by other methods such as welding, as long as effective connection is ensured.

In this embodiment, only one cross arm 1200 is provided on transmission tower 1000.

In other embodiments, the number of cross arms installed on the transmission tower is not limited, and may be one, two, three or even more, as the case may be. The relative position of each cross arm is also not limited, and the cross arms can be symmetrically arranged on the same horizontal plane, or can be positioned on two sides of the power transmission tower but not on the same horizontal plane. The connection mode of the cross arm and the tower body is not limited to bolt connection, and other modes such as welding can be adopted, so long as the effective connection of the cross arm and the tower body can be ensured.

The power transmission tower 1000 of the embodiment is simple in structure, the mode that the metal cross arm 1220 and the composite cross arm 1230 are combined is adopted, the characteristic that the shorter the length of the composite component is, the higher the strength is utilized, the strength advantage of the composite material and the insulation advantage of the material of the composite material are fully exerted, and in addition, the strength advantage of the metal material is eliminated, so that the diagonal insulator is omitted, and the cost of the power transmission tower engineering is reduced.

Example two:

as shown in fig. 3, the present embodiment provides a power transmission tower 2000, which is different from the first embodiment in that the cross arm 2200 of the present embodiment includes two cross arm groups 2210, and further includes an outer connector 2280 and an inner connector 2270, and the two cross arm groups 2210 are combined to form a parallel structure, so that the bending resistance of the composite cross arm 2200 is higher.

Fig. 3 is combined with fig. 4 to show that, in this embodiment, the cross arm 2200 includes two cross arm groups 2210, each of the two cross arm groups 2210 includes a metal cross arm 2220 and a composite cross arm 2230, one end of each of the two metal cross arms 2220 is connected to a tower body angle 2110 horizontally disposed on the tower body 2100, the other end of each of the two metal cross arms 2220 extends out of the tower body 2100, the other end of each of the two metal cross arms 2220 is connected to one end of each of the two composite cross arms 2230, and the other end of each of the two composite cross arms 2230 is connected to the other end of each of the two composite cross arms 2280, so that the cross arm 2200 forms an integral structure; the ends of two metal cross arms 2220 extending outside of tower 2100 are connected by an inner connector 2270, and inner connector 2270 is positioned to resist the longitudinal tension forces imparted by the hooked wires.

In this embodiment, the metal cross arm 2220 is an L-shaped angle steel, a plurality of through holes are formed at one end of the second limb back 2223 close to the inner flange 2240, through holes corresponding to the through holes on the second limb back 2223 are formed in the inner connecting member 2270, and the inner connecting member 2270 and the second limb back 2223 are fixedly connected with each other through bolts. Inner connectors 2270 enable cross-arm 2200 to resist longitudinal tensile forces associated with hanging wires. In this embodiment, the inner connector 2270 is an L-shaped angle.

In other embodiments, the inner connecting member may be a steel plate or other metal structure, not limited to an angle steel, as long as it can support. In addition, the position of the inner connecting piece is not limited to the end part of the metal cross arm close to the inner flange, and the metal cross arm can extend out of the tower body at any position.

In other embodiments, when the voltage class applied to the transmission tower is smaller, the required length of the cross arm is also smaller, and at the same time, the length of the composite cross arm and the length of the metal cross arm extending out of the tower body are also shorter, so that the longitudinal tensile force applied to the cross arm is also smaller, and the inner connecting piece can be omitted.

In this embodiment, the inner flange 2240 has the same structure as the inner flange 1240 of the first embodiment, and is not described herein again.

In this embodiment, the outer flange 2250 includes a second sleeve 2251 and a second base 2252, the second sleeve 2251 is sleeved on the mandrel 2231, the second base 2252 is a third vertical plate disposed perpendicular to the axial direction of the mandrel 2231, the length of the second base 2252 is greater than the diameter of the second sleeve 2251, the second base 2252 is a rectangular plate, and a plurality of through holes are disposed on the protruding portion of the second base 2252 relative to the second sleeve 2251.

In this embodiment, the external connecting member 2280 includes two L-shaped angle steels 2281, the L-shaped angle steels 2281 include a third limb back 2282 and a fourth limb back 2283, the two third limb backs 2282 are disposed parallel to each other and have a gap for clamping and fixing the protruding portion of the second base 2252 relative to the second sleeve 2251, and the two fourth limb backs 2283 are located on the same horizontal plane, so that the two L-shaped angle steels 2281 are arranged in a T-shaped structure; the end of the third limb back 2282 is provided with a through hole corresponding to the through hole on the second base 2252, and the two third limb backs 2282 are matched with the through holes through bolts so as to clamp and fix the second base 2252; the middle part of the outer connector 2280 is provided with a through hole for connecting the wire-hanging fitting string 2260, and the middle part does not refer to the middle of the outer connector 2280, but refers to other areas except for the area where the outer connector 2280 clamps and fixes the second base 2252. The outer flange 2250 and outer connector 2280 are simple in construction and are easily accessible and replaceable.

In other embodiments, the outer flange and the outer connector may have other structures as long as the composite cross arms are connected to each other and the outer connector may be connected to a wire fixing device. For example, the base of the outer flange is a circular plate, a triangular plate, a trapezoidal plate or the like, the outer connecting piece is a steel plate with the length equal to the distance between the two pillar insulators, and through holes are formed in the corresponding positions where the base and the steel plate are connected through bolts. The lead fixing device is not limited to the wire hanging hardware string, and can be any other device capable of connecting the lead.

In this embodiment, the number of cross arm groups 2210 is two, and the arrangement of two cross arm groups 2210 is higher in strength and rigidity bearing capacity than when only one cross arm group 1110 is provided.

In other embodiments, the number of the cross arm groups may be two or more, and the cross arm groups are designed according to the mechanical performance requirements and the electrical performance requirements of the cross arms.

In this embodiment, the two cross arm groups 2210 are parallel to each other, and the parallel structure ensures the electrical performance of the cross arm 2200, and at the same time, shortens the length of the composite cross arm 2230, and further enables the bending resistance and the pressure resistance of the cross arm 2200 to be higher.

In other embodiments, the two cross arm sets may be positioned in a relationship other than parallel, such as in a trapezoidal configuration with the outer and inner connectors, or in a rectangular configuration with the cross arm sets being non-uniform in length but parallel to each other, etc.

In this embodiment, inner connector 2270 and metal cross arm 2220, outer connector 2280 and composite cross arm 2230 are connected by bolts.

In other embodiments, the components may be welded or the like, as long as effective connection is ensured.

In this embodiment, the two composite cross arms 2230 have the same structure, and the outer flange 2250 and the inner flange 2240 at both ends have the same structure, so that the cross arm 2200 is stressed uniformly and has higher bending strength.

In other embodiments, the two composite cross arms may be of different configurations, for example, one being a composite post insulator with a solid circular cross section core rod and the other being a composite post insulator with a solid square cross section core rod. Or the second base of one outer flange is a rectangular plate, and the second base of the other outer flange is a circular plate, which is not limited in the present application.

The power transmission tower 2000 of this embodiment has a simple structure, and the parallel structure of the cross arm groups 2210 can ensure the electrical performance of the cross arm 2200, and at the same time, shorten the length of the composite cross arm 2230, and further make the bending resistance and compression resistance of the cross arm 2200 higher.

Example three:

as shown in fig. 5, the present embodiment provides a transmission tower 3000, which is different from the second embodiment in that the cross arm 3200 of the present embodiment includes three cross arm groups 3210 and no inner connecting member is provided.

In the present embodiment, three cross arm sets 3210 are parallel to each other and are connected by an outer connector 3280 and an outer flange 3250 in a matching manner, wherein the outer connector 3280 and the outer flange 3250 have the same structure and the same connection manner as the embodiment. The structure of three cross arm groups 3210 makes the bending strength of cross arm 3200 higher, is applicable to the condition that transmission tower 3000 tower body is wider.

In other embodiments, the number of cross arm sets may be three or more to meet different requirements.

In this embodiment, no inner connecting member is provided, mainly because the three cross arm sets 3210 are parallel to each other and have small intervals, and can bear large longitudinal tensile force, so the inner connecting member can be omitted. Of course, if the voltage class to which power transmission tower 3000 is applied is small and the length of cross arm 3200 is also small, then the length of composite cross arm 3230 and the length of metal cross arm 3220 extending out of tower body 3100 are also short, and the longitudinal tensile force to which cross arm 3200 is subjected is also small, and the interconnectors may be omitted.

In other embodiments, when the voltage level applied to the transmission tower is high, or when the distance between the tower bodies is large, which results in a large distance between the three cross arm groups, the inner connecting member as in the second embodiment can be used to resist the longitudinal tensile force of the cross arms caused by the hanging wires.

Example four:

as shown in fig. 6, the present embodiment provides a transmission tower 4000, which is different from the second embodiment in that a cross arm 4200 of the present embodiment is a two-arm cross arm, which meets the requirement of hanging wires at two ends of the transmission tower 4000.

In this embodiment, two ends of the metal cross arm 4220 extend out of the tower body 4100, two ends of the metal cross arm 4220 extending out of the tower body 4100 are connected to the composite cross arm 4230, and the two composite cross arms 4230 at two ends of the tower body 4100 are connected by two external connecting pieces 4280, respectively, so that the cross arm 4200 forms an integral structure; the ends of metal cross arms 4220 on both sides of tower 4100 are connected to inner link 4270 to resist the longitudinal tension forces caused by the hitching wires.

In other embodiments, when the voltage class applied to the transmission tower is smaller, the required length of the cross arm is also smaller, and at the same time, the length of the composite cross arm and the length of the metal cross arm extending out of the tower body are also shorter, so that the longitudinal tensile force applied to the cross arm is also smaller, and the inner connecting piece can be omitted. The inner connecting piece can be arranged on one side and not arranged on the other side according to different applicable environments and different hanging wires, and is determined according to specific needs without limitation.

In this embodiment, the length of the metal cross arm 4220 extending out of the two ends of the tower body 4100 is the same, so as to ensure uniform stress. Both ends are connected with composite cross arms 4230, which meets the requirement of hanging wires at both ends of the power transmission tower 4000.

In other embodiments, the length of the metal cross arm extending out of the two ends of the tower body may be different as long as the stability of the transmission tower is ensured.

In this embodiment, the structure and connection manner of the two composite cross arms 4230 and the outer connecting member 4280, and the structure and connection manner of the inner connecting member 4270 and the tower body 4100 are the same as those of the embodiment, and are not described herein again.

In other embodiments, the composite cross arm structure connected to the two ends of the metal cross arm may be different, and may be changed according to specific requirements.

While the invention has been described with reference to the above disclosure, it will be understood by those skilled in the art that various changes and modifications in the above-described structures and materials, including combinations of features disclosed herein either individually or in any combination, will be apparent to one skilled in the art from the disclosure herein. These variants and/or combinations fall within the technical field of the present invention and are intended to be protected by the following claims.

Claims (10)

1. The utility model provides a power transmission tower, includes the body of the tower and fixes the cross arm on the body of the tower which characterized in that: the cross arms comprise at least one cross arm group, and the cross arm group comprises metal cross arms and composite cross arms;

one end of the metal cross arm is connected with the tower body, the metal cross arm extends out of the tower body, the other end of the metal cross arm is connected with one end of the composite cross arm, and the other end of the composite cross arm is connected with a conducting wire in a hanging mode.

2. The transmission tower of claim 1, wherein: the composite cross arm is a composite post insulator which comprises an inner flange and a core rod, wherein the inner flange is sleeved on the core rod and is connected with the metal cross arm.

3. The transmission tower of claim 2, wherein: the inner flange comprises a first sleeve and a first base, the first sleeve is sleeved on the mandrel, the first base comprises two first vertical plates and two first vertical plates, the first vertical plates are axially arranged on the mandrel, the first vertical plates are parallel to each other and perpendicular to the first sleeve.

4. The transmission tower of claim 3, wherein: the metal cross arm comprises two L-shaped angle steels which are arranged in a T shape, and the first vertical plate and the two L-shaped angle steels are mutually clamped and fixed.

5. The transmission tower of claim 3, wherein: the metal cross arm is T-shaped angle steel and comprises a first transverse plate and a second vertical plate perpendicular to the first transverse plate, and the second vertical plate is clamped and fixed by the first vertical plate.

6. The transmission tower of claim 2, wherein: the number of the cross arm groups is at least two, and the cross arm groups are parallel to each other.

7. The transmission tower of claim 6, wherein: the cross arm still includes the interior connecting piece, the interior connecting piece is the angle steel, the interior connecting piece with at least two the metal cross arm links to each other.

8. The transmission tower of claim 6, wherein: the composite post insulator comprises an outer flange, the outer flange comprises a second sleeve and a second base, the second sleeve is sleeved on the mandrel, the second base is perpendicular to a third vertical plate axially arranged on the mandrel, the length of the third vertical plate is larger than the diameter of the second sleeve, and the outer flange is connected with the outer flange through an outer connecting piece.

9. The transmission tower of claim 8, wherein: the outer connecting piece comprises two L-shaped angle steels which are arranged in a T shape, the two L-shaped angle steels are clamped and fixed on the second base, and the outer connecting piece is provided with a wire connecting device.

10. The transmission tower of claim 1, wherein: the cross arm is a double-arm cross arm, and the two ends of the metal cross arm are both connected with the composite cross arm.

Images