High-Voltage Bushing Holed Spacer Impregnation
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Solution Overview
Problem
The impregnation process in current high voltage bushings is slow, limiting the production efficiency and restricting the use of matrix materials to only low-viscosity, unfilled polymers, which affects the thermomechanical properties and production time.
Innovation Solution
A bushing design featuring a sheet-like spacer with multiple holes that facilitates faster impregnation by reducing flow resistance, allowing the use of alternative materials and particle-filled polymers, and enhancing thermomechanical stability through the incorporation of fibers and filler particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the spacer is made without holes (conventional design), then the structural integrity is maintained, but the impregnation process is slow due to high flow resistance
Solution Approach 1:
The spacer is designed with a multitude of holes penetrating it substantially in the direction of its short dimension, creating a porous structure that facilitates rapid penetration of matrix material while maintaining structural integrity through the distributed hole pattern
Solution Approach 2:
The spacer is divided into multiple layers wound in spiral form around the conductor, with holes distributed across each layer. This segmentation creates multiple flow paths for the matrix material, reducing overall flow resistance and accelerating impregnation
2Strength
If low-viscosity unfilled polymers are used as matrix material (conventional restriction), then the impregnation process is feasible, but the thermomechanical properties are limited
Solution Approach 1:
The holed spacer structure allows particle-filled polymers and higher viscosity materials to penetrate effectively by providing multiple flow paths and reduced flow resistance, enabling the use of matrix materials with superior thermomechanical properties that would otherwise be difficult to impregnate
Solution Approach 2:
The invention enables the use of composite matrix materials containing filler particles (such as aluminum oxide, silicon oxide, or other inorganic fillers) mixed with polymer resins, providing enhanced thermomechanical strength, thermal conductivity, and dimensional stability while maintaining manufacturability through the holed spacer design
3Productivity
If paper spacer is used without holes, then the mechanical stability is provided, but the drying process before impregnation is slow and critical
Solution Approach 1:
The holed spacer structure provides rapid evaporation pathways for water during drying and rapid matrix material penetration pathways during impregnation, dramatically reducing the critical drying time and eliminating water content control issues that plague conventional paper spacers
Solution Approach 2:
The holes in the spacer structure extract the problematic function of water retention from the paper material, allowing rapid water removal during drying while maintaining the mechanical stability function of the spacer through the distributed hole pattern
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 design accelerates the impregnation process, reduces production time, and improves thermomechanical properties by enabling the use of a variety of matrix materials, including particle-filled polymers, leading to enhanced current ratings, reduced weight and size, and improved fracture toughness.
Implementation Method 1
The holes can facilitate and accelerate the penetration of the wound spacer (core) with the matrix material. With unpierced paper, as in the state of the art, the matrix material has to creep through one paper layer in order to move radially from between a pair of two neighboring spacer layers to a neighboring pair of two neighboring spacer layers. If the spacer comprises a multitude of holes, the exchange of matrix material in radial direction can be strongly facilitated, and also the penetration of the core of wound spacer material in axial direction can be strongly facilitated, since there is less flow resistance due to more space.
Implementation Method 2
If the spacer comprises a multitude of holes, the exchange of matrix material in radial direction can be strongly facilitated
Implementation Method 3
If the holes are large enough and the winding is done accordingly, channels will form within the core, that will quickly guide the matrix material through the core during impregnation.
Data Source
AI summary
An exemplary high-voltage bushing has a conductor and a core surrounding the conductor, wherein the core includes a sheet-like spacer, which spacer is impregnated with an electrically insulating matrix material. The spacer can have a multitude of holes that are fillable with the matrix material. The spacer can be net-shaped or meshed. It can be a net of fibers. The bushing can be a fine-graded bushing with equalizing plates within the core. As a matrix material, a particle-filled resin can be used.