Power Cable Connector Assembly to Prevent Insulation Shrinkback

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Solution Overview

Problem

Existing power cable accessories face issues with insulation shrinkback due to mechanical stresses and temperature, leading to electrical breakdown risks, particularly in cross-linked polyethylene (XLPE) insulation systems.

Innovation Solution

A power cable accessory assembly featuring a fastening device attached to the electrical insulation layer, with a connector that engages via a structure such as a circumferential groove or pins, ensuring an axially fixed position to prevent shrinkback, using thermosetting or thermoplastic polymers and bayonet connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the insulation layer is mechanically connected to the connector using anchor elements and flanges, then the connection strength is improved, but the reliability deteriorates due to bending and disengagement at elevated temperatures

Engineering Contradiction:
Improveconnection strengthVSAvoidreliability at elevated temperature
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

A restraining element is introduced as an intermediary component between the flange and the connector. This restraining element prevents the flange from bending radially outward and disengaging from the anchor elements when thermal expansion occurs, thereby maintaining reliable connection at elevated temperatures while preserving the mechanical strength provided by the flange-connector assembly

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The solution changes the mechanical parameters of the connection system by adding a restraining element that alters the stress distribution and movement characteristics of the flange under thermal load, preventing the harmful radial bending motion that occurs in conventional designs

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If the insulation layer is allowed to shrink freely, then the ease of manufacture is improved, but the reliability deteriorates due to shrinkback and electrical breakdown risks

Engineering Contradiction:
Improveease of insulation installationVSAvoidelectrical insulation reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The restraining element is pre-installed on the connector before the insulation layer is positioned. This preliminary action ensures that when the insulation layer is later installed and subjected to thermal shrinkage, the restraining element is already in place to prevent shrinkback, thereby maintaining electrical reliability without complicating the insulation installation process

Inventive Principle:
Principle #10Preliminary action

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 assembly effectively prevents or reduces insulation shrinkback, maintaining electrical integrity and facilitating intuitive installation by ensuring a secure connection between the connector and insulation layer.

Implementation Method 1

the connector has an inner surface provided with a structure that engages with the fastening device to maintain an axially fixed position between the connector and the electrical insulation layer

Methodology Applied
Scientific EffectMechanical constraint: Mechanical Force

Implementation Method 2

The electrical insulation layer may comprise a thermosetting polymer such as crosslinked polythyelene. Thermosetting polymers are hardened, making the solution in which the connector engages with the electrical insulation layer by means of the fastening device more durable

Methodology Applied
Scientific EffectThermosetting polymer hardening: Phase Change

Data Source

PatentEP4632977A1Power cable accessory assembly
Publication Date: 2025.10.15 NKT HV CABLES AB
  • EP4632977A1 patent drawingFigure 1~2
  • EP4632977A1 patent drawingFigure 3
  • EP4632977A1 patent drawing

AI summary

A power cable accessory assembly (1.1) comprising: a power cable (3) comprising: a conductor (5), and an electrical insulation layer (7) arranged around the conductor (5); a fastening device (11a) attached to an end face (7.1) of the electrical insulation layer (7), and a connector (9) mechanically connected to the conductor (5), wherein the connector (9) has an inner surface provided with a structure that engages with the fastening device (11a) to maintain an axially fixed position between the connector (9) and the electrical insulation layer (7).