CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a national phase entry under 35 U.S.C. § 371 of International Application No. PCT/CN2017/093791, filed Jul. 21, 2017, which claims priority from Chinese Patent Application Nos. 201610597271.9, filed Jul. 26, 2016 and 201610594229.1, filed Jul. 26, 2016, all of which are hereby incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a technical field of power transmission and transformation devices, and more particularly, to a cross arm, and an angle tower and a tension tower including the same.

BACKGROUND

In an overhead transmission line, a transmission tower functions to support a conducting wire. Specifically, the conducting wire is supported by a cross arm fixed on the transmission tower. The specific connection means is hanging the conducting wire at a free end of the cross arm of the transmission tower.

An angle tower is a transmission tower used to change a route direction of a line when the route direction is required to be changed. As shown inFIG. 1, a conventional angle tower10has an outer corner11and an inner corner12. The conducting wire13at the inner corner12tends to be away from the angle tower10, and the conducting wire14at the outer corner11tends to approach first and then to be away from the angle tower10. There is a requirement on a minimum electrical clearance between the conducting wire and the angle tower10. Generally, the distance between the conducting wire and the angle tower10is increased by increasing the length of the cross arm to meet the electrical clearance requirement, but an excessively long cross arm multiplies the production difficulties.

A tension tower is commonly used to withstand unbalanced tension, and force on the conducting wire is generally transferred to the tower body by a tension string. The tension tower includes a line tension tower, an angle tower and a terminal tower, which can withstand the horizontal load generated by conducting wires and ground wires. The conducting wires on both sides of the tension tower need to be connected by a jumper wire. As shown inFIG. 2, in a conventional tension tower20, the jumper wire needs to be performed by using a tension insulator string21and related fittings. The use of the tension insulator string21and the fittings makes the vertical spacing between the cross arms22very large, and makes the tower head23have a complicated structure with a large size, which is inconvenient for maintenance and installation. It causes that the tension tower20is costly, the load caused by the conducting wire and the wind load on the tower head are large, and the tower body is heavy.

SUMMARY

In view of the disadvantages of the prior art, one objective of the present disclosure is to provide a cross arm which is used on an angle tower to support a conducting wire, so that the electrical clearance between the conducting wire and the tower body can be satisfied without increasing the length of the cross arm. Another objective of the present disclosure is to provide a cross arm that can be used on a tension tower to support a conducting wire, so that the tension insulators and complicated connections between fittings can be cancelled. Thus the interlayer spacing of the conducting wires is narrowed, and the size of the tower head of the tension tower is reduced. As a result, the structure is simplified and the cost is reduced.

In order to achieve the mentioned objectives, the present disclosure adopts the following technical solutions.

According to one aspect of present disclosure, a cross arm applied to an angle tower is provided. Said angle tower includes a tower body. An end of said cross arm is connected to said tower body, and another end of said cross arm away from said tower body is a free end for connecting a conducting wire. Said free end comprises an end connecting member and an elongate member fixed to said end connecting member. In a horizontal projection, said elongate member extends outward from said end connecting member. Said conducting wire is connected to said elongate member. An angle between said elongate member and a center line of said cross arm is greater than an angle between said conducting wire and said center line of said cross arm.

There is a requirement on a minimum electrical clearance between the conducting wire and the tower body. The electrical clearance is related to the shortest space distance from the conducting wire to the tower body. The minimum electrical clearance can avoid causing the flashover and assure the personal safety. According to the present disclosure, in the horizontal projection, said elongate member extends outward from said free end in a direction parallel with or away from said tower body, so the distance between two hanging points of two conducting wires at the corner can be increased. Then the distance between the conducting wire and the tower body can be increased, that is, the electrical clearance between the conducting wire and the tower body is increased without changing the length of the cross arm.

Preferably, said elongate member is arranged on both sides of said end connecting member. The two conducting wires at the corner can be hung on the elongate members arranged on the both sides of the end connecting member respectively, so that the distance between the conducting wire and the tower body can be increased.

Preferably, one said elongate member is arranged on said end connecting member, and two conducting wires at a corner are respectively connected to both ends of said elongate member. The elongate member can be mounted on the end connecting member as a whole, which only needs to be fixed to the free end.

Preferably, said elongate member is joined by a plurality of segments of supports. The appropriate number of supports may be chosen to assemble an elongate member with a desired length as required to meet the electrical clearance requirement between the conducting wire and the tower body. In addition, when the elongate member needs to be long, it is flexible to assemble such elongate member in a form of multi-segment supports.

Preferably, at least one reinforcing member is arranged on said elongate member. The arrangement of the reinforcing member can enhance the strength and structural stability of the elongate member.

Preferably, said at least one reinforcing member is connected to said end connecting member and said end connecting member. The reinforcing member, the elongate member and the end connecting member may form a stable triangular structure that further enhances the strength of the elongate member.

Preferably, at least one auxiliary member is arranged between said reinforcing member and said elongate member, and said auxiliary member is connected to said reinforcing member and said elongate member. The arrangement of the auxiliary member further increases the rigidity of the elongate member.

Preferably, said elongate member is arranged at an outer corner of said angle tower. At the outer corner, the conducting wire at the corner approaches first and moves away from the tower body, which is easy to cause the electrical clearance between the conducting wire and the tower body not to satisfy the requirement. The arrangement of the elongate member at the outer corner of the angle tower can increase the distance between the two conducting wires and the tower body at the outer corner.

Preferably, said cross arm is a composite cross arm.

An angle tower is also provided according to present disclosure. The angle tower includes the tower body and the cross arm mentioned above. The angle tower can meet the requirement on the electrical clearance between the conducting wire and the tower body without increasing the length of the cross arm.

According to another aspect of present disclosure, a cross arm applied to a tension tower is provided. Said tension tower includes a tower body. An end of said cross arm is connected to said tower body, and another end of said cross arm away from the tower body is a free end for connecting a conducting wire. Said free end is provided with an end connecting member and a jumper device. Said jumper device is horizontally arranged on said end connecting member and configured to be hung with a jumper wire.

The jumper device is horizontally arranged on the end connecting member, then the jumper device will not occupy the vertical space, thus the interlayer spacing of the conducting wires can be narrowed. And the tension insulators and the complicated connections between fittings can be cancelled. Thus the size of the tower head of the tension tower is reduced, the structure is simplified and the cost is reduced.

Preferably, said jumper device is a composite post insulator, an end of said composite post insulator is connected to said end connecting member, and another end of said composite post insulator is hung with said jumper wire. The jumper device is configured as a composite post insulator, which can optimize the electric field of the cross arm.

Preferably, said composite post insulator is hung with said jumper wire by a connecting fitting. It is convenient for connection and installing.

Preferably, said tension tower is an angle tower. Said end connecting member is further connected to an elongate member. In a horizontal projection, said elongate member extends outward from said end connecting member. Said conducting wire is connected to said elongate member. An angle between said elongate member and a center line of said cross arm is greater than an angle between said conducting wire and a center line of said cross arm.

In an angle tower, there is a requirement on the minimum electrical clearance between the conducting wire and the tower body. The electrical clearance is related to the shortest space distance from the conducting wire to the tower body. The minimum electrical clearance can avoid causing the flashover and assure the personal safety. According to the present disclosure, in the horizontal projection, said elongate member extends outward from said free end in a direction parallel with or away from said tower body. The distance between the two hanging points of the two conducting wires on both sides of the tower body can be increased. Then the distance between the conducting wire and the tower body can be increased, that is, the electrical clearance between the conducting wire and the tower body can be increased without changing the length of the cross arm.

Preferably, said elongate member is arranged on both sides of said end connecting member. The two conducting wires on both sides of the tower can be hung on the elongate members arranged on the both sides of the end connecting member, so that the distance between the conducting wire and the tower body can be increased.

Preferably, one said elongate member is arranged on said end connecting member, and two conducting wires on both sides of said tower body are respectively connected to both ends of said elongate member. The elongate member can be mounted on the end connecting member as a whole, which only needs to be fixed to the free end.

Preferably, at least one reinforcing member is arranged on said elongate member. The arrangement of the reinforcing member may enhance the strength and structural stability of the elongate member.

Preferably, said at least one reinforcing member is connected to said elongate member and said end connecting member. The reinforcing member, the elongate member and the end connecting member may form a stable triangular structure that further enhances the strength of the elongate member.

Preferably, said cross arm is a composite cross arm.

A tension tower is provided according to present disclosure. The tension tower includes said tower body and said cross arm. The size of the tower head of the tension tower is small, the material cost is saved and the installation is convenient.

