Residual Current Device Magnetic Core DC Detection

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Solution Overview

Problem

Current residual current devices are unable to perform diagnostic functions on internal faults, are complex and costly to manufacture, consume high power, and are inefficient in detecting DC residual currents.

Innovation Solution

An electronic device with a control unit, sensing stage, and trip unit that includes a magnetic core and secondary winding arrangement, capable of auto-diagnostic functionalities, low power consumption, and flexible operation for both DC and AC residual current detection, featuring a compact design and integration of modules for efficient fault detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If complex detection arrangements are implemented to sense DC residual currents, then detection capability is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:

ImproveDC residual current detection capabilityVSAvoiddetection arrangement complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex electronic detection arrangements with a magnetic core-based sensing system that uses magnetic flux detection to sense DC residual currents. This substitution of magnetic field detection for complex electronic circuits simplifies the overall device structure while maintaining detection capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the detection parameter from direct electrical measurement to magnetic flux measurement. By detecting changes in magnetic flux through the magnetic core caused by DC residual currents, the system achieves simplified detection architecture with reduced component count and lower manufacturing cost.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If advanced detection electronics are used for residual current sensing, then detection performance is improved, but power consumption increases

Engineering Contradiction:

Improveresidual current detection performanceVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent replaces power-hungry electronic detection circuits with a passive magnetic core-based sensing system. The magnetic core naturally responds to DC residual currents through magnetic flux changes, eliminating the need for continuous power supply to detection electronics and significantly reducing overall power consumption.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If diagnostic functionalities are added to check internal faults, then reliability is improved, but device complexity increases

Engineering Contradiction:

Improveinternal fault detection capabilityVSAvoidelectronic stage complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent incorporates diagnostic capabilities that continuously monitor the operational status of internal components through the magnetic sensing system. By using the existing magnetic flux detection mechanism to also detect internal faults, the system achieves reliability improvement without adding separate diagnostic hardware, thus avoiding increased device complexity.

Inventive Principle:

Principle #10Preliminary action

4Ease of manufacture

If the device structure is simplified to reduce size and manufacturing cost, then ease of manufacture is improved, but detection capability may be compromised

Engineering Contradiction:

Improvemanufacturing simplicity and costVSAvoidresidual current detection capability

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent replaces complex electronic detection circuits with a magnetic core-based sensing system that is inherently simpler to manufacture. The magnetic core and associated passive components can be produced using standard manufacturing techniques, reducing both complexity and cost while maintaining full detection capability for DC and AC residual currents.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 effectively detects internal faults, reduces power consumption, and enhances reliability and flexibility in detecting both DC and AC residual currents, while being cost-effective and simple to manufacture.

Implementation Method 1

detection module (3) operatively coupled with the line conductors (P, N) of an electric line (100). The detection module includes a magnetic core (3A) enchaining the line conductors (P, N) of the electric line (100) and a secondary winding arrangement (3B) coupled to the magnetic core (3A) and including a secondary winding (31) wound around the magnetic core (3A)

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The secondary winding arrangement (3B) is adapted to receive in input at least a driving voltage (VA, VB) configured to make the magnetic core (3A) operate in a magnetic saturation condition

Methodology Applied

Scientific EffectMagnetic saturation: Magnetic Saturation

Data Source

PatentEP4050349A1A residual current device for low voltage electric lines

Publication Date: 2022.08.31 ABB (SCHWEIZ) AG

Figure 1
Figure 2
Figure 2A

AI summary

An electronic device for a LV electric line including one or more conductors comprising a sensing stage 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 internal fault conditions in said electronic device.