Feeding Line Arc Interruption Using Thermal Triggered Cutoff

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Solution Overview

Problem

In electric systems for rail vehicles, arcing faults between the electrical energy source and sink pose a significant risk of fire, particularly in confined spaces like tunnels, due to induced voltages and limited space for conventional circuit breakers, which are ineffective in interrupting phase-to-phase arcing efficiently.

Innovation Solution

An arrangement along the feeding line, comprising a temperature-dependent member that activates irreversible movement of movable means to cut off arcs and remove hot ionized gases, forming a sealed room to extinguish the arc, utilizing materials like arc-resistant tubes, clamping members, and ventilation tubes to manage pressure and cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional circuit breaker is used to protect against arcing faults, then the device can interrupt normal circuit operation, but it is ineffective in interrupting phase-to-phase arcing and requires several meters of cable distance which is not available in confined bogie spaces

Engineering Contradiction:
Improveprotection against arcing faultsVSAvoidspace requirement for circuit breaker
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent extracts the arc interruption function from the conventional circuit breaker and implements it locally at the fault point using a temperature-dependent member that activates only when arcing occurs, eliminating the need for a large circuit breaker in the bogie

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a temperature-dependent member as an intermediary between the feeding line and the electrical energy source, which activates upon temperature increase from arcing to trigger irreversible movement that cuts off the arc, providing local arc interruption without requiring a conventional circuit breaker

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the electrical energy source is disconnected from the fault by reducing induced voltage, then arcing can be stopped, but this requires reducing train speed or allowing the arc to destroy the electric machine

Engineering Contradiction:
Improvearc interruptionVSAvoidtrain operation continuity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent converts the harmful high temperature from arcing into a beneficial trigger signal by using a temperature-dependent member that activates when the temperature increases, transforming the destructive thermal effect into a protective mechanism that interrupts the arc without affecting train operation

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of operation

If a temperature-dependent member is used to activate irreversible movement for cutting off arcs, then local arc interruption is achieved without requiring conventional circuit breaker space, but the system requires irreversible movement mechanisms and arc-resistant materials

Engineering Contradiction:
Improvespace efficiency in bogieVSAvoidirreversible movement mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent implements a self-service mechanism where the temperature-dependent member automatically activates irreversible movement in response to temperature increase from arcing, eliminating the need for external control systems or additional sensors, thereby reducing overall system complexity despite the irreversible movement mechanism

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent employs arc-resistant materials and a disposable irreversible movement mechanism that activates once during an arcing event, designed to be replaced rather than repaired, reducing the need for complex recovery or reset mechanisms

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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

Effectively interrupts arcing by leveraging temperature increases from power dissipation to trigger irreversible physical movements, preventing arc propagation and reducing the risk of equipment damage, offering a reliable and efficient solution beyond conventional circuit breakers.

Implementation Method 1

a temperature dependent member arranged close to the feeding line in said position and configured to, upon an increase of the temperature thereof above a predetermined level, activate an irreversible movement of movable means included in the arrangement

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

configured to by this movement cut off the arc (a) and/or remove hot ionized gases required to maintain the arc so as to prevent the arcing from proceeding in this feeding line

Methodology Applied
Scientific EffectPhysical displacement: Displacement

Implementation Method 3

upon an increase of the temperature thereof above a predetermined level, which temperature increase is caused by power dissipation during arcing

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3585640B1An electric system
Publication Date: 2024.05.15 ALSTOM HOLDINGS SA
  • EP3585640B1 patent drawingFigure 1a
  • EP3585640B1 patent drawingFigure 1b
  • EP3585640B1 patent drawingFigure 1c

AI summary

An electric system has an electrical energy source connected to an electrical energy sink by at least one feeding line. Each feeding line (8) is in at least one position therealong between said source and said sink provided with an arrangement configured to interrupt arcing in the feeding line would such arcing reach this position. The arrangement has a temperature dependent member which upon an increase of the temperature thereof above a predetermined level activates an irreversible movement of movable means (24) which by this movement cuts off the arc (a) and/or removes hot ionized gases (28) and by that prevents the arcing to continue in the feeding line past the arrangement.