Feedthrough Insulator Field Control for Clean-Air Dielectric Strength

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Solution Overview

Problem

Conventional bushing insulators in gas-insulated electrical power transmission devices face challenges with the reduced dielectric strength of clean air compared to sulfur hexafluoride, leading to increased costs due to higher filling pressures and insulation distances, and the long-term stability of fluorinated gas mixtures is not adequately assured, posing environmental risks.

Innovation Solution

A feedthrough insulator with a base body made of an electrically insulating main material and a field control material that influences the electric field, featuring a coating, embedded electrodes, or admixtures like zinc oxide or barium titanate to enhance dielectric strength in clean air environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If clean air is used as insulating medium instead of sulfur hexafluoride, then environmental friendliness is improved, but dielectric strength is reduced to approximately one-third

Engineering Contradiction:
Improveenvironmental impactVSAvoiddielectric strength
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent changes the physical parameters of the insulating system by introducing field-controlling materials that modify the electric field distribution. This allows clean air to achieve sufficient dielectric strength through optimized field control rather than relying solely on gas composition or pressure increases.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite structures combining different field-controlling materials (semiconducting coatings, varistor materials, dielectric materials) with the insulating components. These composites create optimized electric field distributions that enhance the overall dielectric performance of clean air insulated systems.

Inventive Principle:
Principle #40Composite materials

2Reliability

If higher filling pressures are used to compensate for reduced dielectric strength, then dielectric strength is improved, but cost of pressure vessels increases significantly

Engineering Contradiction:
Improvedielectric strengthVSAvoidcost of pressure vessels
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of changing the pressure parameter, the patent modifies the electric field distribution through field-controlling materials. This approach maintains standard operating pressures while achieving the required dielectric strength through optimized field geometry and material properties.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical approach of increasing pressure to improve dielectric strength with an electromagnetic approach using field-controlling materials. This substitution eliminates the need for expensive high-pressure vessels while achieving the same or better insulating performance.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If fluorinated gas mixtures are used to achieve similar dielectric strength as SF6, then dielectric strength is improved, but long-term stability and environmental persistence are not sufficiently assured

Engineering Contradiction:
Improvedielectric strengthVSAvoidlong-term stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the approach from modifying gas composition to modifying field distribution. By using field-controlling materials with clean air, the system achieves high dielectric strength without relying on unstable fluorinated gas mixtures, ensuring long-term operational stability.

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

The solution effectively increases the dielectric strength of bushing insulators in clean air environments, reducing costs and mitigating environmental concerns by stabilizing the insulating gas mixture, thus addressing the limitations of sulfur hexafluoride and fluorinated alternatives.

Implementation Method 1

The field-controlling material is designed and/or arranged such that it influences an electric field penetrating and surrounding the feedthrough insulator

Methodology Applied
Scientific EffectElectric field control: Electric Field

Implementation Method 2

the field-controlling material forming the at least partial coating of the base body is semiconducting

Methodology Applied
Scientific EffectSemiconducting property: Conduction (electrical)

Implementation Method 3

the base body is made of the main material with an admixture of an electrically conductive varistor material as a field control material. For example, the varistor material comprises zinc oxide

Methodology Applied
Scientific EffectVaristor effect: Electrical Resistance

Implementation Method 4

the base body is made of the main material with an admixture of dielectric field-controlling material that increases its permittivity. For example, the dielectric field-controlling material comprises barium titanate and/or aluminum oxide

Methodology Applied
Scientific EffectDielectric permittivity: Dielectric Permittivity

Data Source

PatentEP4297051A1Feedthrough insulator
Publication Date: 2023.12.27 SIEMENS ENERGY GLOBAL GMBH & CO KG
  • EP4297051A1 patent drawingFigure 1~2
  • EP4297051A1 patent drawingFigure 3~4
  • EP4297051A1 patent drawingFigure 5~6

AI summary

The invention relates to a feedthrough insulator (1). The feedthrough insulator (1) has a base body (5) with at least one opening (6) suitable for passing through at least one electrical conductor (7). The feedthrough insulator (1) is made of an electrically insulating main material (8) and at least one field-controlling material (10) different from the main material (8). The field-controlling material (10) is designed and/or arranged such that it influences an electric field penetrating and surrounding the feedthrough insulator (1).