Metal Switchgear Enclosure with Bulkhead Partitions for High Pressure

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Solution Overview

Problem

Metal enclosures for gas-insulated switchgear face challenges in withstanding higher pressures required for effective insulation using gases like dry air, N2, or CO2, which are less environmentally friendly than SF6, without increasing size or weight, and traditional enclosures become heavy and expensive when pressurized above 1.5 bar abs.

Innovation Solution

The design incorporates partition walls that protrude outside the metal enclosure, providing bulkheads that increase pressure withstand by anchoring forces between metal walls, and using corrugated metal walls and modular construction to enhance strength and anchoring, allowing for pressures up to 4.0 bar abs without the need for larger enclosures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the pressure of gas inside the metal enclosure is increased to improve dielectric withstand, then the insulation performance is improved, but the forces on the metal enclosure walls increase requiring thicker and heavier walls

Engineering Contradiction:
Improvedielectric withstandVSAvoidmetal enclosure weight
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The metal enclosure is divided into multiple volumes by partition walls that protrude outside the enclosure. This segmentation allows the internal pressure forces to be distributed and counterbalanced across multiple surfaces, reducing the net force on each individual wall section and enabling lighter wall construction while maintaining high internal pressure for dielectric withstand.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The partition walls extend in a third dimension by protruding outside the enclosure boundaries. This dimensional extension creates additional force distribution surfaces and anchoring points, allowing the structure to withstand higher internal pressures without increasing the weight of the main enclosure walls.

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

2Strength

If traditional metal enclosures are designed to withstand high pressures above 1.5 bar abs, then the pressure withstand capability is improved, but the enclosure becomes heavy and expensive

Engineering Contradiction:
Improvepressure withstandVSAvoidenclosure weight
Core Design Contradiction:
StrengthVSWeight of stationary object

Solution Approach 1:

By segmenting the enclosure into multiple volumes with partition walls that protrude outward, the structure distributes pressure forces across multiple surfaces. This allows the enclosure to achieve high pressure withstand capability (above 1.5 bar abs) without requiring uniformly thick and heavy walls throughout, thereby reducing overall weight and cost.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the metal enclosure size is increased to accommodate better insulation for alternative gases, then the insulation performance is improved, but the enclosure volume and footprint increase

Engineering Contradiction:
Improveinsulation performanceVSAvoidenclosure volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The invention changes the pressure parameter of the gas inside the enclosure to achieve adequate insulation performance for alternative gases like dry air, N2, or CO2. By increasing the gas pressure, sufficient dielectric strength is obtained without needing to increase the physical dimensions or volume of the enclosure, thereby maintaining a compact footprint.

Inventive Principle:
Principle #35Parameter changes

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 enables metal enclosures to effectively withstand higher pressures, maintaining a compact size while supporting the use of environmentally friendlier gases, reducing the weight and cost associated with traditional high-pressure enclosures.

Implementation Method 1

The partition walls greatly increase the pressure withstand of the complete metal enclosure. With the partition walls attached to the metal walls, forces that try to push one wall out to hold the opposite wall in place.

Methodology Applied
Scientific EffectForce anchoring: Mechanical Force

Implementation Method 2

Corrugated metal walls increase the strength of the metal walls and thus increase the pressure withstand of the metal enclosure.

Methodology Applied
Scientific EffectCorrugation strengthening: Corrugation

Implementation Method 3

The gas is selected to provide electrical insulation inside the metal enclosure and typical gas is SF6 although other gases are also applicable such as dry air, N2, CO2 or mixture of two or three of N2, O2, CO2.

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Implementation Method 4

The dielectric withstand of the gas is proportional to the pressure inside the metal enclosure.

Methodology Applied
Scientific EffectPressure-dependent dielectric strength: Dielectric Permittivity

Data Source

PatentEP4485721A1A metal enclosure for electrical switchgear
Publication Date: 2025.01.01 ABB (SCHWEIZ) AG
  • EP4485721A1 patent drawingFigure 1
  • EP4485721A1 patent drawingFigure 2
  • EP4485721A1 patent drawingFigure 3

AI summary

The present invention relates to a metal enclosure (100, 200) for electrical switchgear, the metal enclosure is configured to be pressurized above atmospheric pressure, the metal enclosure comprising: metal walls (102, 104, 106, 108, 110, 111) sealing outer perimeters of at least two volumes (118, 119) for accommodating different sets of electrical switchgear, at least one partition wall (116, 216) that separates the volumes for the different sets of electrical switchgear, the at least one partition wall is attached to the outer perimeter metal walls of the respective volumes that the respective at least one partition wall define, wherein the at least one partition wall protrudes outside the metal walls outer perimeters.