Flexible Capacitive Voltage Sensor for Shrinkable Cable Joints

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Solution Overview

Problem

Existing shrinkable cable joints face safety and elasticity issues due to rigid metallic inserts and lack of adaptability, posing risks for operators and hindering effective voltage detection.

Innovation Solution

A capacitive voltage sensor with a flexible design, featuring a sensor insulating layer, sensor and guard electrodes, and a conductive layer, integrated between the screen and semiconductive layers, allowing for safe and elastic voltage detection within the joint.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a rigid metallic insert is used for voltage detection, then voltage sensing capability is provided, but safety risks increase and adaptability to joint modifications is lost

Engineering Contradiction:
Improvevoltage detection capabilityVSAvoidoperator safety risks
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces rigid metallic inserts with a flexible capacitive sensor comprising a sensor electrode, guard electrode, and insulating layer that can safely integrate into the joint structure. The flexible design eliminates sharp edges and rigid components that pose safety risks to operators while maintaining voltage detection functionality through capacitive coupling between the sensor electrode and the cable insulation.

Inventive Principle:
Principle #30Flexible shells and thin films

2Measurement precision

If a rigid metal insert is used in the sensor accessory, then voltage detection is enabled, but elasticity and adaptability to cable size changes are eliminated

Engineering Contradiction:
Improvevoltage sensing functionVSAvoidadaptability to joint modification
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The sensor accessory employs a flexible capacitive sensor structure with thin film electrodes and insulating layers that can elastically deform and adapt to changes in joint dimensions. This flexible design allows the sensor to maintain effective capacitive coupling with the cable insulation regardless of cable size variations or joint modifications, eliminating the rigidity constraint of metallic inserts.

Inventive Principle:
Principle #30Flexible shells and thin films

3Measurement precision

If a capacitive test point structure extending into insulating material is used, then voltage detection is achieved, but structural complexity increases

Engineering Contradiction:
Improvevoltage detection capabilityVSAvoidsensor structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent integrates the capacitive sensor directly into the joint structure by merging the sensor electrode, guard electrode, and insulating layer with the joint's existing insulating and semiconductive layers. This integration eliminates the need for separate, complex test point structures extending into insulating materials, as the joint structure itself serves as part of the capacitive sensor system.

Inventive Principle:
Principle #5Merging (Combining)

4Ease of operation

If a sensor accessory without electrical screening is used, then access to capacitive insert is enabled, but fault current drainage capability is lost and temperature increases

Engineering Contradiction:
Improveaccess to voltage signalVSAvoidjoint temperature
Core Design Contradiction:
Ease of operationVSTemperature

Solution Approach 1:

The patent introduces a guard electrode as an intermediary element between the sensor electrode and the joint structure. The guard electrode is connected to ground through the semiconductive layer, providing a controlled path for fault current drainage while maintaining electrical isolation of the sensor electrode. This intermediary structure enables safe access to the voltage signal while preventing uncontrolled current flow and temperature rise.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 enhances safety and adaptability by providing a flexible and non-complex structure for voltage sensing, reducing the risk of operator exposure and enabling seamless integration into shrinkable cable joints, while maintaining high impermeability and efficient voltage detection.

Implementation Method 1

a capacitive voltage sensor arranged between the joint screen layer and the joint semiconductive layer and comprising: a sensor insulating layer having a first side and an opposite second side; a sensor electrode and a guard electrode arranged on the second side

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3647796B1Shrinkable cable joint and voltage sensor
Publication Date: 2023.06.07 PRYSMIAN SPA
  • EP3647796B1 patent drawingFigure 1
  • EP3647796B1 patent drawingFigure 2a~2c
  • EP3647796B1 patent drawingFigure 3a~3b

AI summary

It is described a shrinkable cable joint (200) comprising: a joint insulating layer (211) surrounding a connection region configured to house two connected cable ends; a joint semiconductive layer (206) surrounding the joint insulating layer (211); a joint screen layer (204) surrounding the joint semiconductive layer (206); a joint sheath (203) surrounding the joint screen layer (204); and a capacitive voltage sensor (100) arranged between the joint screen layer (204) and said joint semiconductive layer (206) and comprising: a sensor insulating layer (1) having a first side (2) and an opposite second side (3); a sensor electrode (4) and a guard electrode (5) arranged on said second side (3) and directly contacting the joint semiconductive layer (206); a sensor conductive layer (6) arranged on said first side (2) and comprising a first conductive layer portion (13) in direct contact with the joint screen layer (204) and electrically connected to the guard electrode (5) and a second conductive layer portion (14) electrically connected to the sensor electrode (4); the sensor conductive layer (6) extending on the first side (2).