Rogowski Coil Sensor Dielectric Enclosure for Current Accuracy

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Solution Overview

Problem

Existing current sensor devices in utility meters, such as transformer and Rogowski coils, are either bulky and expensive or provide limited accuracy, especially during low and high current conditions, requiring multiple calibration processes that increase manufacturing time and cost.

Innovation Solution

A Rogowski coil sensor device with a dielectric material having a dielectric constant of at least 3.5 is used to enclose the coil, positioning it between the coil and the conductor, reducing capacitance and improving accuracy across a range of currents and voltages, thereby simplifying calibration and reducing manufacturing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a Rogowski coil is used to sense current, then the device size is reduced compared to transformer sensors, but measurement precision deteriorates during low and high current conditions

Engineering Contradiction:
Improvesensor device sizeVSAvoidcurrent sensing accuracy
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

A dielectric material with dielectric constant of at least 3.5 is positioned between the Rogowski coil and the conductor to reduce parasitic capacitance effects. This intermediary material mediates the electromagnetic interaction, improving measurement precision across the full current range while maintaining the compact Rogowski coil structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the electrical parameters of the sensing system by introducing a dielectric material with specific dielectric constant (≥3.5). This parameter change reduces the parasitic capacitance between the coil and conductor, thereby improving measurement accuracy without increasing device volume.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If multiple calibration processes are performed to improve accuracy, then measurement precision improves, but productivity decreases due to increased manufacturing time

Engineering Contradiction:
Improvecurrent sensing accuracyVSAvoidmanufacturing speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The dielectric material is pre-installed between the Rogowski coil and conductor during manufacturing, establishing optimal electrical characteristics before the sensing operation begins. This preliminary action eliminates the need for multiple post-assembly calibration processes, maintaining high precision while improving productivity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The dielectric material structure provides self-calibration functionality by inherently reducing parasitic capacitance effects. The physical configuration itself performs the correction that would otherwise require multiple manual calibration processes, achieving both high precision and manufacturing efficiency.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If a dielectric material with dielectric constant of at least 3.5 is positioned between the Rogowski coil and conductor, then measurement precision improves across different current conditions, but device complexity increases

Engineering Contradiction:
Improvecurrent sensing accuracyVSAvoidsensor structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The dielectric material is implemented as a thin film or layer positioned between the coil and conductor. This thin-film approach provides the necessary electrical isolation and capacitance reduction while adding minimal structural complexity and maintaining a compact overall device design.

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 provides improved accuracy and reduced calibration requirements, allowing for consistent current sensing across different operating voltages and currents, resulting in cost savings and faster manufacturing times while maintaining high accuracy.

Implementation Method 1

reducing capacitance and improving accuracy across a range of currents and voltages

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

a dielectric material having a dielectric constant of at least 3.5 is used to enclose the coil, positioning it between the coil and the conductor

Methodology Applied
Scientific EffectDielectric: Dielectric

Data Source

PatentEP2568299B1Sensor devices and methods for use in sensing current through a conductor
Publication Date: 2021.04.14 ACLARA METERS LLC
  • EP2568299B1 patent drawingFigure 1
  • EP2568299B1 patent drawingFigure 2
  • EP2568299B1 patent drawingFigure 3~4

AI summary

Sensor devices and related methods disclosed. One example sensor device (12) includes a Rogowski coil (104) defining an aperture (110) and a dielectric material (108) at least partially enclosing the Rogowski coil. The dielectric material has a dielectric constant of at least about 3.5. The dielectric material is configured such that, when a conductor (14) is at least partially inserted within the aperture, at least a portion of the dielectric material is positioned between the Rogowski coil and the conductor.