Auxiliary Device Diagnosing Electrical Protection Tripping Causes

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Solution Overview

Problem

Existing methods for diagnosing the cause of tripping in electrical protection devices often result in erroneous diagnoses, particularly due to the limitations of auxiliary devices in accurately distinguishing between short circuits and overloads, which can lead to incorrect fault identification.

Innovation Solution

An auxiliary device equipped with current sensors and an electronic processing unit that calculates specific threshold values and records current intensity values over time intervals to independently diagnose the cause of tripping, sending diagnostic messages via wireless communication, thereby improving diagnosis reliability without requiring replacement of existing protection devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If auxiliary devices are added to provide monitoring and diagnostic functions, then diagnostic capability is improved, but device complexity increases

Engineering Contradiction:
Improvediagnostic capabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

An auxiliary device acts as an intermediary between the electrical protection device and the monitoring system. The auxiliary device includes current sensors that measure current in the conductor and an electronic processing unit that analyzes the current waveform to determine trip causes, thereby providing diagnostic capability without replacing existing protection devices.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The auxiliary device performs multiple functions: it measures current, analyzes current waveforms, determines trip causes (short circuit or overload), and communicates diagnostic information. This multi-functionality consolidates what would otherwise require multiple separate devices into a single integrated auxiliary device.

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

2Device complexity

If conventional diagnostic methods are used, then device simplicity is maintained, but measurement precision deteriorates leading to erroneous diagnoses

Engineering Contradiction:
Improvedevice simplicityVSAvoiddiagnosis accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The diagnostic method dynamically analyzes the current waveform characteristics before tripping occurs. The electronic processing unit examines the shape, amplitude, and temporal characteristics of the current waveform to distinguish between short circuit and overload conditions, adapting the diagnosis based on the specific waveform patterns observed rather than using fixed thresholds alone.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the parameter being measured from simple current magnitude to detailed current waveform characteristics. By analyzing the temporal profile, peak values, and shape of the current waveform, the system can differentiate between fault types that would appear similar if only steady-state current magnitude were considered.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If auxiliary devices replace existing protection devices, then diagnostic function is integrated, but ease of operation worsens requiring full replacement

Engineering Contradiction:
Improveintegration capabilityVSAvoidinstallation ease
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The auxiliary device is installed as an intermediary component alongside the existing electrical protection device rather than replacing it. The auxiliary device measures current in the same conductor and provides diagnostic information while the original protection device continues to perform its protective function, allowing incremental upgrade of existing installations.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution enhances the accuracy of fault identification by using calculated threshold values and recorded current values to differentiate between short circuits and overloads, reducing the likelihood of erroneous diagnoses and facilitating integration with existing electrical installations.

Implementation Method 1

an auxiliary device for an electrical installation comprising an electrical protection device associated with at least one electrical conductor, the auxiliary device comprising a current sensor associated with the electrical conductor

Methodology Applied
Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Data Source

PatentEP3629042B1Method for diagnosing the cause of triggering of an electrical protection device, auxiliary device and electrical system for implementing such a method
Publication Date: 2023.05.10 SCHNEIDER ELECTRIC IND SAS
  • EP3629042B1 patent drawingFigure 1~3
  • EP3629042B1 patent drawingFigure 4~6
  • EP3629042B1 patent drawingFigure 7~8

AI summary

This method for diagnosing the cause of tripping of an electrical protection device involves, after detection by the auxiliary device of a loss of electrical supply, the determination of a type of electrical fault from recorded values, the determination comprising: - the comparison, with a first threshold value, of the highest value of the maximum current intensity among the values ​​recorded for several measurement intervals preceding the loss of supply, a short circuit being diagnosed if the highest value of the maximum current intensity is greater than a first threshold value; - the comparison, with a second threshold value, of the highest value of the RMS value of the current among the recorded values, an overload being diagnosed if the highest value of the RMS value is greater than a second threshold value.