Transformer Sealing Compound for Heat Dissipation and 10 KV Isolation

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Solution Overview

Problem

Existing thermal conductive compounds for power transformers do not adequately address the need for increased heat dissipation while maintaining electrical isolation and mechanical integrity, especially under high electrical voltages.

Innovation Solution

A thermal conductive compound comprising a silicone resin with a combination of natural mineral fillers, aluminium hydroxide, and a limited amount of thermoconductive and electroconductive particles, which provides enhanced thermal conductivity and electrical isolation up to 10 KV, and is used to seal and encapsulate power transformer assemblies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If thermal conductive compound is used to increase heat dissipation, then thermal conductivity is improved, but electrical isolation is compromised

Engineering Contradiction:
Improveheat dissipationVSAvoidelectrical isolation
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent changes the electrical parameter of the thermal conductive compound by limiting electroconductive particles to less than 5% by weight, transforming it from a potentially conductive state to an electrically isolated state while maintaining thermal performance above 1.5 W/mK

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite thermal conductive compound combining thermally conductive particles (metallic particles, metal oxides, or graphite) with a silicone resin matrix, where the composite structure provides both thermal conductivity and electrical isolation properties

Inventive Principle:
Principle #40Composite materials

2Temperature

If inorganic fillers are added to increase thermal conductivity, then thermal conductivity is improved, but linear expansion coefficient increases

Engineering Contradiction:
Improvethermal conductivityVSAvoidlinear expansion coefficient
Core Design Contradiction:
TemperatureVSLength of moving object

Solution Approach 1:

The patent changes the thermal and dimensional parameters by selecting specific inorganic fillers (metallic particles, metal oxides, graphite) with controlled sizes (0.1-2.0 mm) and proportions, achieving thermal conductivity above 1.5 W/mK while maintaining linear expansion coefficient below 300 x 10^-6/K

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by using a heterogeneous distribution of different particle types and sizes within the silicone resin matrix, where thermally conductive particles are dispersed to provide heat dissipation pathways without creating uniform thermal expansion

Inventive Principle:
Principle #3Local quality

3Temperature

If electroconductive particles are added to improve thermal conductivity, then thermal dissipation is improved, but electrical resistance decreases

Engineering Contradiction:
Improvethermal dissipationVSAvoidelectrical resistance
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent precisely controls the concentration of electroconductive particles, limiting them to less than 5% by weight of the total compound, which maintains electrical resistance above 10 MΩ at 10 KV while achieving thermal conductivity above 1.5 W/mK

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The silicone resin matrix acts as an intermediary that surrounds and isolates the electroconductive particles, allowing thermal energy to be conducted through the particles while the resin matrix maintains electrical isolation between them

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The compound significantly increases thermal dissipation capabilities and ensures electrical isolation, reducing linear expansion coefficients and improving heat evacuation, while maintaining mechanical protection and reducing manufacturing costs.

Implementation Method 1

a given amount of aluminium hydroxide lowering the linear expansion coefficient and increasing the thermal conductivity of said silicone resin

Methodology Applied
Scientific EffectLinear expansion: Thermal Expansion

Implementation Method 2

a third filler comprising a given limited amount of thermoconductive and electroconductive particles providing an electrical resistance to the thermal conductive compound which ensures an electrical isolation of the thermal conductive compound under an electrical voltage above 10 KV

Methodology Applied
Scientific EffectElectrical resistance: Electrical Resistance

Implementation Method 3

The compound significantly increases thermal dissipation capabilities and ensures electrical isolation, reducing linear expansion coefficients and improving heat evacuation

Methodology Applied
Scientific EffectThermal conductivity: Conduction (thermal)

Data Source

PatentEP3796342B1A power transformer assembly and a thermal conductive compound for sealing a power transformer assembly
Publication Date: 2023.11.01 PREMO SL
  • EP3796342B1 patent drawingFigure 1~2
  • EP3796342B1 patent drawingFigure 3

AI summary

A power transformer assembly and a thermal conductive compound for sealing a power transformer assembly are disclosed. The power transformed assembly has a magnetic core with at least first and second wound coils that are sealed by a thermal conductive compound comprised of a silicone resin and fillers. The fillers at least include a first filler, or main filler, and a second filler. The second filler includes a given amount of aluminium hydroxide lowering linear expansion coefficient and increasing the thermal conductivity of said silicone resin. The first filler is a natural mineral filler.