Cross Arm Extension Piece for Electrical Clearance

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Solution Overview

Problem

Conventional transmission towers face challenges in maintaining electrical clearance between conducting wires and tower bodies without increasing cross arm length, and have complex structures with large sizes and high costs due to excessive use of tension insulators and fittings.

Innovation Solution

The introduction of a cross arm design with an elongate member that extends outward from the end connecting member, allowing for increased electrical clearance without lengthening the cross arm, and a jumper device that replaces tension insulators, simplifying the structure and reducing costs by eliminating complex connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the length of the cross arm is increased to meet the electrical clearance requirement, then the electrical clearance between the conducting wire and the angle tower is improved, but the production difficulties are multiplied

Engineering Contradiction:
Improveelectrical clearanceVSAvoidproduction difficulties
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent introduces an elongate member that extends outward from the end connecting member in a direction that is not along the longitudinal axis of the cross arm. This adds a new spatial dimension to the structure, allowing the conducting wire to be positioned farther from the tower body through lateral extension rather than increasing the cross arm length, thereby resolving the contradiction between electrical clearance and manufacturing complexity

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If tension insulator strings and fittings are used to connect jumper wires, then the electrical clearance is maintained, but the vertical spacing between cross arms becomes very large and the tower head structure becomes complicated

Engineering Contradiction:
Improveelectrical clearanceVSAvoidtower head structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the tension insulator string and fittings from the system by providing a jumper wire support structure that is directly integrated into the cross arm. This removal of unnecessary components simplifies the tower head structure, reduces vertical spacing requirements, and maintains electrical clearance through the geometric configuration of the elongate member rather than through insulating components

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If tension insulator strings and fittings are used, then the jumper wire connection is achieved, but the load on the tower head increases and the tower body becomes heavy

Engineering Contradiction:
Improvejumper wire connectionVSAvoidtower body
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent replaces heavy, permanent tension insulator string structures with a lighter, simpler jumper wire support structure that is directly integrated into the cross arm. This substitution uses lighter materials and a more straightforward structural approach, reducing the overall weight of the tower body while maintaining the necessary electrical connection functionality

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Data Source

PatentEP3492674B1Cross arm for angle towers
Publication Date: 2023.07.12 SHANGHAI SHEMAR POWER ENG CO LTD
  • EP3492674B1 patent drawingFigure 1~2
  • EP3492674B1 patent drawingFigure 3~4
  • EP3492674B1 patent drawingFigure 5~6

AI summary

Provided is a cross arm(110), one end of which is connected to a tower body (101), and the end of the cross arm (110) away from the tower body (101) is a free end for connecting a conducting wire (103). The free end comprises an end connecting piece (111) and an extension piece (112). The extension piece (112) is fixed with the end connecting piece (111). In a horizontal projection, the extension piece (112) protrudes from the end connecting piece (111) and the conducting wire (103) is connected to the extension piece (112). The angle between the extension piece (112) and a center line of the cross arm (110) is greater than the angle between the conducting wire (103) and the center line of the cross arm (110). The free end of the cross arm (110) is further provided with a jumper wire device (120), which is horizontally arranged on the end connecting piece (111) and is used for hitching the jumper wire. By using the extension piece, the distance between the conducting wire and the tower body can be increased under the condition that the turning angle is met, thereby the requirement for a electrical gap between the conducting wire and the tower body is met, and there is no need to increase the length of the cross arm. By horizontally arranging the jumper wire device on the end connecting piece, the jumper wire device does not occupy the space in the vertical direction, thereby the distance between wire layers can be reduced, and therefore the size of the tower body can be reduced.