Inorganic Insulation Sheet for High-Dielectric Transformer Lamination

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Solution Overview

Problem

Cellulose-based insulation materials for electrical transformers have limitations such as low dielectric strength, water affinity, poor thermal degradation properties, and high shrinkage, which restrict their use at higher temperatures and lead to increased transformer size and drying time.

Innovation Solution

An electrically insulating inorganic sheet comprising at least 90% by weight inorganic particles and a binder, which forms a laminate with other insulation materials, providing enhanced dielectric strength and thermal conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If cellulose-based insulation materials are used in transformers, then cost is reduced and ease of manufacture is improved, but dielectric strength is insufficient and thermal degradation properties are poor

Engineering Contradiction:
Improveease of manufactureVSAvoiddielectric strength
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies composite materials by combining cellulose fibers with inorganic particles (such as aluminum oxide, silicon oxide, or magnesium hydroxide) to create a hybrid insulation material. This composite structure allows the material to retain the cost-effectiveness and manufacturability of cellulose while gaining the high dielectric strength and thermal stability of inorganic particles, directly resolving the contradiction between ease of manufacture and reliability

Inventive Principle:
Principle #40Composite materials

2Reliability

If excess cellulose insulating materials are used to compensate for poor characteristics, then dielectric integrity is improved, but transformer size increases and drying time increases

Engineering Contradiction:
Improvedielectric integrityVSAvoidtransformer size
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent changes the physical and chemical parameters of the insulation material by incorporating inorganic particles with specific properties (high dielectric constant, low water absorption, thermal stability). This parameter change allows achieving the required dielectric integrity with reduced material quantity, thus preventing transformer size increase while maintaining reliability

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If cellulose insulation materials are used, then cost is reduced, but affinity towards water increases and thermal degradation properties deteriorate

Engineering Contradiction:
ImprovecostVSAvoidwater affinity
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent uses composite materials where hydrophobic inorganic particles (such as aluminum oxide or silicon oxide) are dispersed in the cellulose matrix. These inorganic particles have low water absorption properties that counterbalance the hygroscopic nature of cellulose, reducing overall water affinity while maintaining cost-effectiveness. The inorganic particles also provide thermal stability, preventing thermal degradation

Inventive Principle:
Principle #40Composite materials

4Reliability

If inorganic nanoparticles are added as filler material, then dielectric properties are improved, but material complexity increases

Engineering Contradiction:
Improvedielectric propertiesVSAvoidmaterial complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by strategically distributing inorganic particles within the cellulose matrix rather than creating a uniformly complex material. The inorganic particles are concentrated in regions where enhanced dielectric strength is most needed, while maintaining the overall simplicity of the cellulose-based structure. This localized enhancement improves dielectric properties without proportionally increasing material complexity

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3069868B1Inorganic electrical insulation material
Publication Date: 2025.06.04 ABB (SCHWEIZ) AG
  • EP3069868B1 patent drawingFigure 1~2
  • EP3069868B1 patent drawingFigure 3~4

AI summary

The present disclosure relates to an electrically insulating inorganic sheet 1 comprising at least 90% by weight inorganic particles 2, and a binder 3 which binds the particles together to form the sheet, for use as solid insulation in an electrical device, e.g. a power transformer.