Composite Crossarm Triangular Insulator Layout for Tower Stability

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Solution Overview

Problem

Existing composite crossarms in power transmission towers are prone to instability and failure when insulators break, lacking sufficient structural stability and maintenance efficiency.

Innovation Solution

A composite crossarm design featuring two post insulators and two suspension insulators forming a stable triangular structure with specific angles, combined with features like hollow insulating tubes, radially symmetric sheds, and enhanced sealing and bonding mechanisms to improve torsion and bending strength, and allow for adjustable mounting and self-cleaning properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single-post or single-suspension structure is used, then the device complexity is reduced, but the reliability deteriorates because the whole composite crossarm may fail when one insulator breaks

Engineering Contradiction:
Improvestructure complexityVSAvoidcrossarm stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The composite crossarm is divided into multiple independent insulator units (two post insulators and two suspension insulators) that are separately mounted and can independently bear load. This segmentation ensures that failure of one unit does not compromise the entire structure, directly resolving the reliability issue while maintaining reasonable complexity through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The design incorporates redundant insulator units that serve as backup components before failure occurs. When one insulator breaks, the remaining units continue to support the crossarm, providing a cushioning effect that prevents catastrophic failure and allows for planned maintenance rather than emergency replacement

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Manufacturing precision

If the angle between insulators is not optimized, then the manufacturing precision is reduced, but the strength deteriorates due to insufficient stress distribution

Engineering Contradiction:
Improveangle precisionVSAvoidcomposite crossarm strength
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The patent specifies precise angular parameters (20°-50° between post insulators, 15°-45° between post and suspension insulators) that optimize both stress distribution and manufacturing feasibility. These parameter ranges balance the competing requirements of structural strength and manufacturing precision by providing target zones rather than single fixed values

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If solid-core post insulator columns are used, then the manufacturing precision is improved, but the ease of operation deteriorates due to lack of maintenance access

Engineering Contradiction:
Improveinsulator structure precisionVSAvoidmaintenance accessibility
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The insulator design incorporates nested structures where internal components (such as grading rings, sealing elements, and monitoring devices) are housed within the insulator body. This nesting allows precise manufacturing of the outer structure while providing access points and maintenance channels that enable operation and maintenance without compromising structural integrity

Inventive Principle:
Principle #7Nested doll (Nesting)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The design enhances the stability and durability of the composite crossarm, reduces maintenance needs, and ensures effective mounting of grading rings while maintaining structural integrity under stress.

Implementation Method 1

The insulating body is set as a hollow insulating tube, and the insulating gas with an absolute pressure value ranging from 0.1 MPa to 0.15 MPa, which can prevent daily maintenance and monitoring of the post insulator

Methodology Applied
Scientific EffectInsulating gas: Dielectric

Data Source

PatentEP4071323B1Composite cross arm and power transmission tower
Publication Date: 2026.02.11 JIANGSU SHENMA ELECTRIC CO LTD
  • EP4071323B1 patent drawingFigure 1
  • EP4071323B1 patent drawingFigure 2~3
  • EP4071323B1 patent drawingFigure 4~6

AI summary

The present application discloses a composite crossarm and a power transmission tower. The composite crossarm includes two post insulators and two suspension insulators. Of the two post insulators and the two suspension insulators, one ends are configured to be connected to a tower body of a power transmission tower, and the other ends are connected together to form an end portion of the composite crossarm to hang a power transmission line. The two suspension insulators are located on same sides of the two post insulators and respectively arranged adjacent to the two post insulators. At the same time, an angle between the two post insulators ranges from 20° to 50°, and an angle between the post insulator and the suspension insulator adjacent thereto ranges from 15° to 45°. The composite crossarm according to the present application is highly stable and can provide favorable conditions for mounting a first grading ring on the post insulator and mounting a second grading ring on the suspension insulator.