Residual Current Device Using Magnetic Saturation Detection

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Solution Overview

Problem

Current residual current devices for low voltage electric lines are complex, expensive, and consume high power, making them inefficient and costly to manufacture, while also lacking flexibility in detecting both DC and AC residual currents.

Innovation Solution

An electronic device with a compact sensing stage using a magnetic core and secondary winding arrangement, coupled with a comparator and processing module, that detects residual currents by operating the magnetic core in saturation conditions and provides a trip or alarm signal based on predefined voltage thresholds, allowing for efficient detection of both DC and AC currents with reduced power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If complex detection arrangements are used to sense DC residual currents, then detection performance is improved, but manufacturing cost increases

Engineering Contradiction:
ImproveDC residual current detection performanceVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces complex electronic detection circuits with a magnetic core-based sensing system that uses magnetic saturation phenomena to detect DC residual currents. The magnetic core with secondary winding arrangement provides detection functionality through magnetic field interactions rather than complex electronic processing, significantly simplifying the detection arrangement and reducing manufacturing costs while maintaining detection precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operating parameters of the magnetic core by controlling the driving voltage to operate the magnetic core in saturation conditions. This parameter change enables the magnetic core to detect both DC and AC residual currents effectively, achieving high detection performance through simple magnetic field-based measurement rather than complex electronic detection circuits.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If complex detection arrangements are used to sense DC residual currents, then detection performance is improved, but device complexity increases

Engineering Contradiction:
ImproveDC residual current detection performanceVSAvoiddetection arrangement complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex electronic detection circuits with a magnetic core-based sensing system that uses magnetic saturation phenomena to detect DC residual currents. The magnetic core with secondary winding arrangement provides detection functionality through magnetic field interactions rather than complex electronic processing, significantly simplifying the detection arrangement and reducing device complexity while maintaining detection precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If high power consumption is accepted in electronic devices, then detection sensitivity is improved, but power efficiency deteriorates

Engineering Contradiction:
Improvedetection sensitivityVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent changes the operating parameters of the magnetic core by controlling the driving voltage to operate the magnetic core in saturation conditions. This parameter change enables the magnetic core to detect both DC and AC residual currents effectively with low power consumption, achieving high detection sensitivity through magnetic field-based measurement rather than high-power electronic processing.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs periodic driving voltage applied to the magnetic core to induce magnetic saturation and detection signals. This periodic action allows the system to achieve high detection sensitivity through repeated magnetic cycling, enabling efficient detection with minimal power consumption compared to continuous high-power electronic detection.

Inventive Principle:
Principle #19Periodic action

4Measurement precision

If specialized DC detection circuits are used, then DC residual current detection is improved, but adaptability to AC currents deteriorates

Engineering Contradiction:
ImproveDC residual current detectionVSAvoidAC residual current detection capability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal detection system where the magnetic core with secondary winding arrangement can detect both DC and AC residual currents through the same magnetic saturation mechanism. The driving voltage control enables the system to adapt to different current types (DC and AC) without requiring separate detection circuits, achieving both specialized DC detection performance and broad adaptability to AC currents.

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

The device achieves high-performance, reliable detection of residual currents with reduced size and manufacturing costs, offering flexibility in operation as a protection device, monitor, or block, while maintaining low power consumption and efficient fault diagnosis.

Implementation Method 1

The secondary winding arrangement is adapted to receive in input at least a driving voltage configured to make the magnetic core to operate in a magnetic saturation condition

Methodology Applied
Scientific EffectMagnetic saturation: Magnetic Saturation

Data Source

PatentEP4050348A1A residual current device for low voltage electric lines
Publication Date: 2022.08.31 ABB (SCHWEIZ) AG
  • EP4050348A1 patent drawingFigure 1
  • EP4050348A1 patent drawingFigure 2
  • EP4050348A1 patent drawingFigure 2A

AI summary

An electronic device (1) for a LV electric line (100) including one or more conductors (P, N), comprising a sensing stage (20) adapted to detect the presence of residual currents in said electric line. Said sensing stage includes an innovative electronic arrangement to detect the presence of residual currents in said electric line.