Elastically Deformable Rogowski Sensor for Safe Cable Insertion

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Solution Overview

Problem

Existing current measurement technologies, such as those using Rogowski torus sensors, require manual intervention to close the torus around electrical cables, posing safety risks and making it difficult in tight spaces, and are sensitive to external electric fields when kept open.

Innovation Solution

A sensor design featuring an elastically deformable support with a Rogowski torus electrical circuit and a handle that allows the cable to be easily inserted and removed from the loop without direct manual intervention, maintaining a secure and precise measurement by using external and internal guides and a position holding element to manage the cable's position relative to the circuit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a torus sensor is used to measure current, then measurement accuracy is improved, but manual closing of the torus is difficult and poses safety problems

Engineering Contradiction:
Improvecurrent measurement accuracyVSAvoidease of closing the torus
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The torus is divided into two separate halves (first and second portions) that can be opened and closed independently. This segmentation allows the torus to be opened for safe cable insertion while maintaining measurement accuracy when closed around the cable.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A cable retention member acts as an intermediary element that secures the cable between the two torus halves. This mediator ensures the cable remains properly positioned during measurement while allowing the torus to be opened and closed safely without direct manual manipulation of the cable.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the torus is kept permanently open to avoid manual closing, then ease of operation is improved, but sensitivity to external electric fields increases

Engineering Contradiction:
Improveease of cable insertionVSAvoidsensitivity to external electric fields
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The torus transitions from a static permanently-open state to a dynamic structure that can be opened and closed as needed. The elastic portions allow the torus to flex open for cable insertion while returning to a closed position during measurement, dynamically adapting to operational requirements.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The physical state of the torus changes between open and closed configurations. By changing the geometric parameter of the torus (from open to closed), the sensor achieves both ease of operation during insertion and reduced sensitivity to external fields during measurement.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If manual intervention is required to close the torus around the cable, then measurement precision can be maintained, but operator safety deteriorates

Engineering Contradiction:
Improvecurrent measurement accuracyVSAvoidoperator safety
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The elastic portions of the torus provide self-service by automatically returning to the closed position after being opened for cable insertion. This eliminates the need for manual closing operations that expose operators to electrical hazards, while maintaining the precise closed configuration needed for accurate measurement.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The elastic portions are pre-designed to provide cushioning force that automatically closes the torus halves together. This beforehand prepared elastic energy ensures the torus closes safely and securely around the cable without requiring dangerous manual intervention by the operator.

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

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 facilitates safe and precise current measurement by allowing the cable to be inserted and removed from the loop without direct manual contact, reducing sensitivity to external fields and improving operator safety and measurement accuracy.

Implementation Method 1

measure industrial currents up to several hundred thousand Hertz using the magnetic field of the current to be measured

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

The electrical cable acts as the primary winding of a transformer, and the sensor's electrical circuit acts as the secondary winding of the transformer. By measuring the characteristics of the voltage induced in the transformer's secondary winding

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2592426B1Sensor for measuring a current in an electric cable
Publication Date: 2024.09.25 SCHNEIDER ELECTRIC IND SAS
  • EP2592426B1 patent drawingFigure 1
  • EP2592426B1 patent drawingFigure 2
  • EP2592426B1 patent drawingFigure 3~4

AI summary

The sensor (1) has a support (6) for an electric circuit (4) elastically deformable between positions in which ends (14, 16) of the support are opposite to and isolated from each other. The support is flexible and formed in such a manner that the support is deformed from one position to another position by manually pressing an opening (12) of the support against an electric cable to pass the cable from outer side of a loop to inner side of the loop/vice versa and the support passes spontaneously from the latter position to the former position when the cable is passed through the opening. An independent claim is also included for a method for measuring current flowing in an electric cable.