Spiral Rod Fitting for Overhead Cable Connection Reliability

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Solution Overview

Problem

Conductor cables in overhead lines face challenges in meeting high electrical and mechanical requirements, particularly during installation and repair, where existing connections may not adequately withstand mechanical loads, electrical stresses, and thermal conditions.

Innovation Solution

A cable connection system using prefabricated spiral rods wound around a press connector or spliced connection area, providing a snug fit with even distribution, reduced contact resistance, and enhanced mechanical and thermal properties, including a paste for improved adhesion and conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If press connectors or spliced connections are used to connect cable ends, then mechanical and electrical connection is achieved, but the connection area experiences high temperature loads and increased contact resistance

Engineering Contradiction:
Improveconnection reliabilityVSAvoidtemperature load in connection area
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The spiral fitting provides an additional parallel current path that equalizes the electrical potential distribution in the connection area, reducing contact resistance and heat generation at critical points. The spiral rods create multiple equipotential surfaces that distribute current flow more uniformly across the connection.

Inventive Principle:
Principle #12Equipotentiality

Solution Approach 2:

The spiral fitting adds a dimensional element around the connection area, creating a three-dimensional current path that supplements the traditional linear connection. This spiral configuration increases the effective surface area for current flow and provides thermal relief through the radial arrangement of spiral rods.

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

2Strength

If press connectors are used to connect cable ends, then mechanical fixation is achieved, but the connection may become loose over time under mechanical loads

Engineering Contradiction:
Improvemechanical strength of connectionVSAvoidconnection stability over time
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The spiral fitting acts as a pre-installed backup mechanism that compensates for potential loosening of the press connector. The spiral rods are positioned and tensioned in advance to provide immediate support if the primary connection deteriorates, cushioning against mechanical failures before they occur.

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

Solution Approach 2:

The spiral fitting changes the mechanical parameters of the connection system by adding torsional stiffness and distributed support points. The spiral configuration transforms point loads into distributed loads along the spiral path, reducing stress concentration and preventing connection loosening under cyclic mechanical loads.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If spiral rods are wound around the connection area, then thermal and electrical contact is improved, but device complexity increases

Engineering Contradiction:
Improveelectrical and thermal contact qualityVSAvoidcomplexity of cable connection system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The spiral fitting serves multiple functions simultaneously: it provides electrical bonding, thermal management, mechanical reinforcement, and corrosion protection. This multi-functionality reduces the need for separate components for each function, thereby managing complexity while achieving multiple performance goals with a single integrated solution.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The spiral rods form a flexible protective shell around the connection area that adapts to the geometry of the conductors. This thin-film-like spiral configuration provides continuous contact and protection without requiring rigid structural components, simplifying the overall design while maintaining effectiveness.

Inventive Principle:
Principle #30Flexible shells and thin films

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 solution achieves a robust, efficient electrical and mechanical connection with reduced temperature loads, minimized corona effects, and strain relief, ensuring the cable connection can handle high currents and mechanical stresses effectively.

Implementation Method 1

The arrangement of the spiral fitting with the spiral rods that are also in contact in the connection area, which in particular are evenly distributed and fit snugly, initially achieves good thermal contact, so that the individual spiral rods act more or less like cooling fins, which reduces the temperature load in the connection area.

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

The spiral rods also achieve a good electrical connection, since the contact resistance in the connection area is reduced due to the lower temperature.

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

the two rope ends are each inserted into the sleeve and the sleeve is then pressed against the rope ends so that they are mechanically fixed in the press connector

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP4054034A1Cable connection and prefabricated spiral bars and method for connecting two cable ends of a cable
Publication Date: 2022.09.07 RICHARD BERGNER HLDG GMBH & CO KG
  • EP4054034A1 patent drawingFigure 1~3
  • EP4054034A1 patent drawingFigure 4~6
  • EP4054034A1 patent drawing

AI summary

The invention relates to a cable connection, in particular of an overhead power line, with a connection area in which two cable ends are joined together, wherein the connection area has a larger diameter than the cable ends and wherein a spiral fitting with several spiral bars is provided, which are wound around the connection area and the adjacent areas of the cable. This improves the electrical, mechanical, and thermal properties in the connection area.