Subsea Power Cable Termination Using Solid Insulator Body

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Solution Overview

Problem

Existing sub-sea power cable termination systems face challenges in maintaining a gas and liquid-tight structure while withstanding mechanical forces and achieving low electrical field stress, often relying on liquid insulation which is vulnerable to water ingress and less effective in high-field environments.

Innovation Solution

A plug-in cable termination assembly using a pressure-compensated housing with a single-phase conductor anchored in a solid insulator body, which is molded around a conducting pin to form a non-elastic, rigid element, providing a gas and liquid-tight connection with a reduced number of components and simplified assembly, and incorporating a design that distributes axial forces effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If liquid insulation is used in cable termination, then electrical insulation is provided, but the system becomes vulnerable to water ingress and requires additional volume for heat expansion

Engineering Contradiction:
Improveprotection against water ingressVSAvoidstructural volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent removes the dielectric liquid from the cable termination system and replaces it with solid insulation materials. The insulator body provides electrical insulation without requiring liquid containment structures, eliminating the vulnerability to water ingress and the need for expansion compensation volume.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the physical state of the insulation medium from liquid to solid. The insulator body is produced from a moldable material that solidifies into a rigid, non-elastic structure, providing both electrical insulation and mechanical stability without the volume expansion issues of liquids.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If multiple barriers and liquid insulation are used, then protection against water ingress is improved, but the device complexity increases

Engineering Contradiction:
Improvegas and liquid tight barrierVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple functions into the insulator body: electrical insulation, mechanical anchoring of the conductor, structural support, and sealing interface with the housing. This single integrated component replaces what would otherwise require multiple separate parts including liquid containment structures and multiple sealing barriers.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The insulator body serves multiple purposes simultaneously: it provides electrical insulation, mechanically secures the conductor through anchoring, forms a sealed interface with the pressure-compensated housing, and supports the conducting pin. This multi-functional design reduces overall system complexity.

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

3Strength

If a rigid insulator body is used, then structural stability and pressure resistance are improved, but adaptability to thermal expansion is reduced

Engineering Contradiction:
Improvewithstand mechanical forcesVSAvoidthermal expansion accommodation
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The patent applies different material properties to different parts of the system: the insulator body is rigid and non-elastic for structural stability, while the pressure-compensated housing provides flexibility for pressure and thermal accommodation. This local differentiation allows each component to optimize its properties for its specific function.

Inventive Principle:
Principle #3Local quality

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 enables a compact, lightweight, and reliable connection that maintains electrical integrity under high pressures and reduces electrical field stress, while being adaptable to various voltage ratings and applications, including sub-sea environments.

Implementation Method 1

an insulator body produced from a moldable material that solidifies about a conducting pin (34) into a non-elastic and rigid body

Methodology Applied
Scientific EffectMolding:

Implementation Method 2

the insulator body is form-fittingly receivable in the pressure-compensated housing under force-transmitting engagement in axial directions through a radial shoulder

Methodology Applied
Scientific EffectForce transmission: Mechanical Force

Implementation Method 3

a pressure-compensated housing, wherein the single-phase conductor is anchored in an insulator body

Methodology Applied
Scientific EffectPressure compensation:

Data Source

PatentEP1994606B1Plug-in termination of a power cable for subsea appliances
Publication Date: 2015.11.11 VETCO GRAY SCANDINAVIA
  • EP1994606B1 patent drawingFigure 1
  • EP1994606B1 patent drawingFigure 2
  • EP1994606B1 patent drawingFigure 3~4

AI summary

A plug-in termination (1) of a single-phase conductor (6) in a power cable termination assembly for submerged use is disclosed, comprising a first barrier separating an outer pressure-compensated housing (11) from the sea; a second barrier separating an inner pressure-compensated housing (18) from the outer pressure-compensated housing, wherein the single-phase conductor runs through the first and second barriers and is secured in the inner pressure-compensated housing by its end being terminated within an insulator body (25) insertable into the inner housing, the unsheathed conductor end (10) electrically connected within said insulator body to a conducting pin (34) which is fixedly embedded by molding into said insulator body (25).