Integrated Current Sensor Layout for Compact Differential Breakers

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Solution Overview

Problem

Existing fault current protection devices face challenges in integrating current measurement for lines and differential current measurement in a compact form, leading to increased complexity and cost, while also compromising precision and space efficiency.

Innovation Solution

A compact current measuring device is designed with a parallelepiped housing that includes upstream and downstream connection pads, current sensors, and a differential current sensor, allowing for the measurement of currents in three-phase lines and a neutral line, enabling the transformation of a conventional circuit breaker into a differential circuit breaker without increasing its size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a separate differential current measurement device is implemented, then differential current measurement capability is improved, but device complexity and installation space increase

Engineering Contradiction:
Improvedifferential current measurement capabilityVSAvoidnumber of devices and connection terminals
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines the differential current measurement function with the existing line current measurement function into a single integrated device. The housing contains both line current sensors and a differential current sensor, eliminating the need for separate differential protection devices and reducing the total number of connection terminals required.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The measurement device is designed to perform multiple functions simultaneously: it measures line currents through individual sensors and measures differential current through a dedicated sensor, all within one universal housing. This multi-functional design replaces what would traditionally require separate specialized devices.

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

2Adaptability or versatility

If the differential current sensor is placed in the extension of current sensors, then differential current measurement is achieved, but the housing size increases making it different from conventional circuit breakers

Engineering Contradiction:
Improvedifferential current measurementVSAvoidhousing length
Core Design Contradiction:
Adaptability or versatilityVSLength of stationary object

Solution Approach 1:

Instead of extending the housing in the same direction as the line current sensors, the differential current sensor is oriented perpendicular to them, along a different spatial dimension. This orthogonal arrangement allows all sensors to coexist within the same housing footprint without increasing the overall length, maintaining compatibility with standard circuit breaker dimensions.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Measurement precision

If the differential current sensor is made oblong to match conductor routing, then sensor coverage is improved, but sensitivity to line currents increases impairing measurement accuracy

Engineering Contradiction:
Improvedifferential current detectionVSAvoidinterference from line currents
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The differential current sensor is designed with a specific geometric configuration where only the conductor carrying differential current passes through its sensing area, while other conductors are positioned outside this specific zone. This localized sensing approach ensures the sensor is sensitive only to the intended differential current and not to line currents flowing in adjacent conductors.

Inventive Principle:
Principle #3Local quality

4Ease of manufacture

If current sensors and differential sensor are oriented along the same axis, then manufacturing is simplified, but the assembly becomes less compact

Engineering Contradiction:
Improvesensor orientation alignmentVSAvoidassembly compactness
Core Design Contradiction:
Ease of manufactureVSVolume of moving object

Solution Approach 1:

The sensors are arranged in three-dimensional space with different orientations rather than all aligned along the same axis. The line current sensors are oriented in one direction while the differential current sensor is oriented perpendicular to them, utilizing vertical and horizontal dimensions to achieve a compact cubic arrangement that reduces overall assembly volume.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 solution allows for precise measurement of currents and differential currents, enhancing protection capabilities while maintaining a compact design, thus simplifying installation and reducing the number of devices needed in an electrical panel.

Implementation Method 1

at least two current sensors, each current sensor being arranged respectively around a current conductor to respectively form a passage of the current conductor

Methodology Applied
Scientific EffectMagnetic field detection: Magnetic Field

Implementation Method 2

a differential current sensor, said differential current sensor being arranged around all of the at least two current conductors to form a common passage to the current conductors

Methodology Applied
Scientific EffectMagnetic field detection: Magnetic Field

Data Source

PatentEP3470853B1Current measuring device, method of manufacture, protection module and differential circuit breaker using such a current measuring device
Publication Date: 2024.10.02 SCHNEIDER ELECTRIC IND SAS
  • EP3470853B1 patent drawingFigure 1
  • EP3470853B1 patent drawingFigure 2
  • EP3470853B1 patent drawingFigure 3

AI summary

A current measurement device comprising current sensors (51, 52) arranged around current conductors to form a passage (51A, 52A) of the current conductors along an axis oriented in a first direction (X), and a differential current sensor (55) arranged around all the current conductors (10, 20) to form a common passage (55A) for the current conductors (10, 20) along an axis oriented in a second direction (Y). The current sensors and the differential current sensor are located in spaces (90, 91) separated by an interface plane (9). The invention also relates to a method for manufacturing such a current measurement device, a protection module (60), and a differential circuit breaker (70) comprising such a device.