U-Shaped Arc Stabilizer for Medium Voltage Switchgear

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In electrical medium-voltage switchgear, arcs during faults can lead to high pressure increases, potentially causing explosive processes and hazards due to arcs occurring from cables to the housing or other cables, which existing solutions do not adequately prevent.

Innovation Solution

The implementation of metal arc stabilizers with a U-shaped cross-section, placed between cables and grounded within the switchgear, to direct arcs towards the stabilizer, reducing the arc's energy and pressure increase by providing a shorter path compared to arcs reaching the housing or other cables.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If arc stabilizers are installed between cables, then arc energy and pressure increase are reduced, but device complexity increases

Engineering Contradiction:
Improvearc energy and pressure increaseVSAvoiddevice complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The arc stabilizer acts as an intermediary element installed between phase cables in the cable connection compartment. It provides a controlled path for arcs to extend to, preventing direct arcing between cables or to the housing. The stabilizer's grounded metal structure with U-shaped cross-section intercepts arcs within a short distance, converting uncontrolled high-energy arcs into controlled low-energy discharges, thereby reducing arc energy and pressure increase while adding only minimal structural complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If arc stabilizers are positioned close to cables, then arc attraction is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvearc attraction effectivenessVSAvoidpositioning precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The arc stabilizer is designed with a U-shaped cross-section where the legs are positioned to face the adjacent phase cables directly. This local geometric configuration creates favorable electric field distribution in the immediate vicinity of the cables, enhancing arc attraction to the stabilizer. The U-shape concentrates the electric field between the cable and the stabilizer legs, ensuring reliable arc interception without requiring extremely tight tolerances on the stabilizer's position relative to the cables.

Inventive Principle:
Principle #3Local quality

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 effectively prevents arcs from reaching the housing, reducing pressure increases and associated hazards by ensuring arcs are attracted to and extinguished on the grounded arc stabilizer, thereby minimizing explosive risks and enhancing safety.

Implementation Method 1

Between two cables of different phase there is an arc stabilizer located in an area where the associated cables extend within the cable compartment. The arc stabilizer is made of metal and fixed in place in the housing.

Methodology Applied
Scientific EffectArc stabilization: Electric Arc

Implementation Method 2

the arc stabilizer is made of metal and fixed in place in the housing... the arc stabilizer is intended to ensure that, in the event of a fault, no arc occurs from an electrical cable to the housing or to another cable, but that the arc only extends from the cable to the associated arc stabilizer connected to the housing

Methodology Applied
Scientific EffectElectrical conduction to ground: Conduction (electrical)

Data Source

PatentEP2273634B1Electric switch assembly, in particular medium voltage medium voltage switching assembly
Publication Date: 2014.09.17 SCHNEIDER ELECTRIC SACHSENWERK
  • EP2273634B1 patent drawingFigure 1
  • EP2273634B1 patent drawingFigure 2a~2b
  • EP2273634B1 patent drawingFigure 3

AI summary

The switchgear has a control panel provided with a metallic housing, and electrical cables (18) provided in a cable terminal compartment and attached to a phase of an electrical power supply. An elongated electric arc stabilizer (24) is provided between the electrical cables of different phases and arranged in a region in which the electrical cables extending within the cable terminal compartment. The stabilizer is metallically formed, is fixedly attached to the housing, and exhibits a U-shaped cross section.