Insulating Layer for Medium Voltage Switchgear Arc Protection

Solution Overview

Problem

Current gas insulated switchgear designs require additional conductive steel bars to protect against arc damage, which increase weight, cost, and generate eddy current losses, and alternative non-ferromagnetic materials further escalate costs without adequately addressing the issue.

Innovation Solution

The inner compartment of medium voltage gas insulated switchgears is equipped with an insulating layer on its inner wall surface, made of ceramic or plastic materials, which prevents direct arc impact and can be complemented with an electrically conductive layer for field compensation, thereby avoiding arc footpoints and potential damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional conductive steel bars are installed to protect against arc damage, then the wall withstand capability is improved, but the weight and cost increase

Engineering Contradiction:

Improvearc damage protectionVSAvoidswitchgear weight

Core Design Contradiction:

ReliabilityVSWeight of stationary object

Solution Approach 1:

The protective function is merged with the existing wall structure by applying an insulating coating layer directly onto the conductive steel wall. This combines the conductive property of steel with the protective property of insulating material, eliminating the need for separate protective bars while maintaining arc damage protection.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The wall is transformed into a composite structure consisting of a conductive steel base layer and an insulating coating layer. This composite material approach allows the wall to simultaneously possess electrical conductivity for structural integrity and insulating properties for arc protection, reducing the need for additional protective components.

Inventive Principle:

Principle #40Composite materials

2Reliability

If additional conductive steel bars are installed to protect against arc damage, then the wall withstand capability is improved, but the cost increases

Engineering Contradiction:

Improvearc damage protectionVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The protective function is merged with the existing wall structure by applying an insulating coating layer directly onto the conductive steel wall. This combines the conductive property of steel with the protective property of insulating material, eliminating the need for separate protective bars while maintaining arc damage protection.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

Instead of using expensive additional steel bars, the solution employs a relatively inexpensive insulating coating layer that can be applied to the existing wall. This coating provides the necessary protection at lower material and manufacturing costs.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If additional steel bars are installed to protect against arc damage, then the wall withstand capability is improved, but eddy current losses increase

Engineering Contradiction:

Improvearc damage protectionVSAvoideddy current losses

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The wall is transformed into a composite structure consisting of a conductive steel base layer and an insulating coating layer. This composite material approach allows the wall to simultaneously possess electrical conductivity for structural integrity and insulating properties for arc protection, reducing the need for additional protective components.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The insulating coating is applied locally to the inner surface of the wall where arc contact occurs, while the bulk steel structure retains its conductivity. This localized insulation prevents eddy currents in the protective layer while maintaining the structural integrity and electrical properties of the steel wall.

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 enhances the compartment's resistance to arc impact, reduces the risk of wall damage, and minimizes eddy current losses, achieving a balance between performance and economic efficiency by using insulating layers that can be thermally managed through cooling means.

Implementation Method 1

an inner compartment, or in case of several inner compartments, an inner of the inner compartment, or one of the inner compartments, is provided on an inner wall surface thereof at least partially with an insulating layer

Methodology Applied

Scientific EffectElectrical insulation: Electrical Resistance

Implementation Method 2

can be complemented with an electrically conductive layer for field compensation, thereby avoiding arc footpoints and potential damage

Methodology Applied

Scientific EffectElectric field compensation: Electric Field

Data Source

PatentUS11527873B2Inner compartment design for medium voltage switchgears

Publication Date: 2022.12.13 ABB (SCHWEIZ) AG

AI summary

An inner compartment for medium voltage gas insulated switchgears includes: at least one inner compartment; and a housing. The inner compartment, or in case of several inner compartments, an inner of the inner compartment, or one of the inner compartments, is provided on an inner wall surface thereof at least partially with an insulating layer.