Current Transformer Phase Opposition De-Saturation

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Solution Overview

Problem

Current transformers in electronic circuit breakers face operational disturbances due to additional coils placed near the primary winding, which saturate the magnetic circuit and hinder the delivery of sufficient voltage to the secondary coil, preventing proper circuit opening.

Innovation Solution

The primary winding and the limiting coil are arranged such that their magnetic fields are in phase opposition, with parallel axes and opposite winding directions, minimizing the disturbing effect of the additional coil's magnetic field and enhancing the transformer's performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional coils are placed in series with the primary winding to increase impedance and limit current, then the current limiting performance is improved, but the magnetic field generated by these coils saturates the magnetic circuit and disturbs the operation of the current transformer

Engineering Contradiction:
Improvecurrent limiting performanceVSAvoidmagnetic saturation of the magnetic circuit
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful magnetic field generated by the additional limiting coil into a beneficial effect by arranging the coil's magnetic field in phase opposition to the primary winding's magnetic field. This opposition actually helps de-saturate the magnetic circuit, transforming the previously harmful saturation effect into a useful de-saturation effect that improves transformer operation.

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

Solution Approach 2:

The patent changes the spatial arrangement and winding direction parameters of the additional coil relative to the primary winding. By positioning the additional coil with its axis parallel to the primary winding and winding it in the opposite direction, the magnetic fields are arranged in phase opposition, which alters the magnetic circuit's saturation characteristics from harmful to beneficial.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If additional coils are added to increase impedance for better current breaking, then the current breaking capability is improved, but the voltage delivery to the electronic card becomes insufficient

Engineering Contradiction:
Improvecurrent breaking capabilityVSAvoidvoltage delivery to electronic card
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The patent transforms the previously harmful magnetic saturation effect into a beneficial de-saturation effect. By arranging the additional coil's magnetic field in phase opposition to the primary winding, the magnetic circuit operates in a less saturated state, which actually improves the transformer's ability to deliver voltage to the electronic card while maintaining the current breaking capability.

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

Solution Approach 2:

The patent modifies the magnetic circuit's operating parameters by changing the relative orientation and winding direction of the additional coil. This parameter change results in a magnetic field configuration that prevents saturation, thereby maintaining sufficient voltage delivery capability even with the additional impedance provided by the limiting coil.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the additional coil is placed in the vicinity of the primary winding, then the impedance increase is achieved, but the magnetic field interference with the transformer operation increases

Engineering Contradiction:
Improveimpedance increase for current limitingVSAvoidmagnetic field interference
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the spatial and directional parameters of the additional coil's magnetic field. By positioning the coil with its axis parallel to the primary winding and winding it in the opposite direction, the magnetic fields are arranged in phase opposition. This parameter change transforms the interference from a harmful saturating effect into a beneficial de-saturation effect that reduces magnetic field interference.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the harmful magnetic field interference generated by the additional limiting coil into a beneficial effect. The magnetic field that was previously causing saturation and interference is now arranged in phase opposition, which de-saturates the magnetic circuit and actually improves the transformer's operation while maintaining the impedance increase needed for current limiting.

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

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 allows the current transformer to supply more energy and improve its performance by de-saturating the magnetic circuit, ensuring effective voltage delivery to the electronic card and proper circuit operation.

Implementation Method 1

the magnetic field generated by the passage of the current in the limiting coil is in phase opposition with that generated by the passage of the current in the primary winding

Methodology Applied
Scientific EffectMagnetic field generation: Electromagnetic Induction

Implementation Method 2

the field generated by the additional coil saturates the magnetic circuit of the current transformer, which has the direct effect of no longer correctly conducting the magnetic flux through the secondary coil

Methodology Applied
Scientific EffectMagnetic saturation: Magnetic Saturation

Data Source

PatentEP3185260A1Transformer for ensuring the power supply for a processing device in an electrical protection apparatus, and apparatus comprising such a transformer
Publication Date: 2017.06.28 SCHNEIDER ELECTRIC IND SAS
  • EP3185260A1 patent drawingFigure 1~3
  • EP3185260A1 patent drawingFigure 4a~5
  • EP3185260A1 patent drawingFigure 6~7c

AI summary

The present invention relates to a current transformer T also intended to provide power to an electronic processing device (7) in an electrical device, said transformer comprising a magnetic circuit (1) through which a primary conductor (2) has a primary winding (3) wound around one part of the magnetic circuit, a secondary winding (6) wound around another part of the magnetic circuit, this secondary winding being intended to provide the energy necessary for the operation of the aforementioned processing device, as well as an additional coil (8) arranged in series with the aforementioned primary winding (3) in the vicinity of the primary winding and intended to increase the impedance of the primary conductor.This transformer is characterized in that the so-called primary winding (3) and the winding (9) of the limiting coil (8) are arranged with respect to each other in such a way that the magnetic field generated by the passage of current in the limiting coil (8) is in opposite phase with that generated by the passage of current in the primary winding (3).