Current Transformer Compensation Winding for Interference Rejection

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Solution Overview

Problem

Current transformer devices are negatively influenced by external magnetic interference fields, leading to inaccurate current measurements due to the division of magnetic flux and induction of interference components in the core element.

Innovation Solution

A current transformer device with a ring-like core element and a compensation winding element arranged in a specific spatial configuration to counteract interference fields, ensuring the magnetic flux through the primary winding is opposite to that through the compensation element, thereby isolating the measurement signal from interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a current transformer device is arranged in an interference field with a homogeneous core element, then the magnetic flux is divided equally in the core element, but a current is induced in the shunt device which transmits interference components to the measurement signal

Engineering Contradiction:
Improvecurrent measurement accuracyVSAvoidinterference field influence
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies the principle of converting harm into benefit by using the compensation winding to transform the harmful interference field into a beneficial compensating effect. The compensation winding is specifically designed to generate a counteracting magnetic flux that opposes the interference flux, thereby converting the harmful interference into a useful compensation mechanism that improves measurement accuracy

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent implements preliminary anti-action by pre-configuring the compensation winding in opposition to the interference field before the interference occurs. The compensation winding is arranged and connected such that it automatically generates a counteracting magnetic flux that opposes the interference flux, preventing the interference from affecting the measurement signal in the first place

Inventive Principle:
Principle #9Preliminary anti-action

2Measurement precision

If a compensation element is added to counteract interference fields, then the measurement accuracy is improved, but the device complexity increases

Engineering Contradiction:
Improvecurrent measurement accuracyVSAvoidstructure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies the principle of merging by integrating the compensation winding into the existing core structure of the current transformer device. The compensation winding is wound around the same core element as the measurement winding, and both windings share the same magnetic path, thereby combining the compensation function with the existing measurement structure rather than adding a separate independent system

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements multi-functionality by designing the compensation winding to serve multiple purposes: it compensates for interference fields, maintains magnetic flux balance in the core, and works in conjunction with the measurement winding to improve overall measurement accuracy. This universal approach allows a single component to address multiple aspects of the measurement system

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

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

This configuration effectively compensates for interference fields, enhancing the accuracy of current measurements by ensuring the compensation element's flux opposes the interference, thus isolating the measurement signal from interference effects.

Implementation Method 1

the magnetic flux in the core element is divided equally. Since due to a comparatively low-impedance shunt device as a further component of a respective current converter device in the core element, i. H. in particular in a section of the core element facing the shunt device, a current is induced

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3370071B1Current transducer device
Publication Date: 2022.07.27 GMC I GOSSEN METRAWATT GMBH
  • EP3370071B1 patent drawingFigure 1
  • EP3370071B1 patent drawingFigure 2

AI summary

Current transformer device (1), comprising: - a ring-shaped or ring-shaped core element (2), - at least one winding element forming part of a winding arrangement (4), wherein the at least one winding element surrounds the core element (2) at least partially, in particular completely, - a ring-shaped or ring-shaped compensation element (10), which is designed to compensate for disturbance fields acting on the current transformer device (1), in particular magnetic fields, wherein the compensation element (10) is arranged in a defined spatial arrangement relative to the core element (2), surrounding the core element (2) and extending along the inner and outer circumference of the core element (2).