Adaptive Electric Arc Detection Using Differential Signals

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Solution Overview

Problem

Existing electric arc detection methods are ineffective for arcs of varying energy levels and are prone to false alarms due to sensitivity to high-frequency noise, requiring significant processing power and being costly, especially when detecting low-intensity or series arcs.

Innovation Solution

An electric arc detection device that uses adaptive inhibition signals and decision aid signals based on current and voltage differential signals to accurately identify arc signatures, synchronized with zero crossings of alternating voltage, and employing multiple detection means for different arc types, reducing false alarms and processing requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If signal processing techniques are used to identify electric arc signatures, then arc detection capability is improved, but sensitivity to high-frequency noise causes false alarms

Engineering Contradiction:
Improvearc detection capabilityVSAvoidfalse alarm rate
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies dynamics by making the detection system adaptive through variable thresholds and weighting factors that change based on operating conditions. The detection algorithm dynamically adjusts its sensitivity parameters according to the measured current and voltage characteristics, allowing it to maintain high detection capability while adapting to different operational states to reduce false alarms from noise.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes parameters by transforming the detection approach from fixed-threshold methods to variable-parameter methods. It uses weighted sums of current and voltage derivatives with adjustable weights, and implements adaptive thresholds based on operating conditions. This parameter transformation allows the system to distinguish arc signatures from noise by changing detection parameters rather than using static criteria.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If existing detection methods are used for all arc types, then detection coverage is improved, but processing power requirements increase significantly

Engineering Contradiction:
Improvedetection coverageVSAvoidprocessing power requirements
Core Design Contradiction:
Adaptability or versatilityVSPower

Solution Approach 1:

The patent segments the detection approach by creating separate detection pathways for different arc types (series arcs, parallel arcs, chafing arcs). Each arc type has specific detection criteria based on characteristic patterns in current and voltage derivatives. This segmentation allows the system to process only relevant signals for each arc type rather than applying comprehensive processing to all signals, reducing overall computational burden while maintaining broad detection coverage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent achieves universality by developing a multi-functional detection framework that can identify multiple arc types using a unified base algorithm. The system uses common measurement of current and voltage derivatives but applies different interpretation rules and thresholds for different arc types. This universal framework reduces processing requirements compared to having separate dedicated systems for each arc type.

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

3Reliability

If thermal protection means are used, then protection against overload and short circuit is improved, but effectiveness against low-intensity arcs deteriorates

Engineering Contradiction:
Improveprotection against overload and short circuitVSAvoiddetection of low-intensity arcs
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent merges thermal protection with electronic arc detection by combining thermal elements that respond to sustained overloads with electronic circuitry that detects rapid arc signatures. The system integrates both protection mechanisms into a unified protection device that can respond to both slow thermal buildup from overloads and rapid temperature spikes from arcs, regardless of intensity. This merging allows the device to maintain thermal protection effectiveness while adding arc detection capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces an intermediary electronic detection system that bridges thermal protection and arc detection. The electronic circuitry acts as an intermediary sensor that detects arc signatures through current and voltage measurements before thermal elements can respond to low-intensity arcs. This intermediary detection system triggers protection mechanisms early for low-intensity arcs while allowing thermal elements to continue providing protection for overload conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP1845599B1Electric arc detection device, cut-off device comprising such a device and electric arc detection method
Publication Date: 2016.09.14 CROUZET AUTOMATISMES SA
  • EP1845599B1 patent drawingFigure 1~2
  • EP1845599B1 patent drawingFigure 3~4
  • EP1845599B1 patent drawingFigure 5~6

AI summary

The invention relates to an electric arc detection device comprising analysis means 2 providing current and voltage integration signals Si(t), Su(t). The analysis means 2 provide current and voltage differential signals dSi(t), dSu(t). Decision means 3 include an inhibition unit INHIBIT providing adaptive inhibition signals Frzi1, Frzi2, ..., Frzin and include detection means DETEC1, DETECT2, DETECT3, ..., DETECTk providing at least one decision aid signal N1, N2, N3, ..., Nk, as a function of at least one adaptive inhibition signal and the current differential signal dSi(t) or the current integration signal Si(t). A decision unit DECIDE provides a trigger signal Trip as a function of the decision aid signals.