Inductive Device Shielding for Dielectric Stress Reduction
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Solution Overview
Problem
High voltage inductive devices, such as transformers, face challenges with size and bulkiness due to large insulation requirements, and traditional shielding systems lead to non-uniform electrical fields and high dielectric creep stresses, as well as difficulties in designing insulation to handle assembly and short circuit forces.
Innovation Solution
A compact inductive device design featuring concentric windings with a metal shield layer stretching between upper and lower parts, providing uniform electrical shielding and eliminating edge-related dielectric stresses, and a layered shielding structure to manage assembly and short circuit forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional separate thin shielding rings are used at top and bottom of the winding, then the shielding structure is simple, but the electrical field becomes non-uniform and high at the shielding rings, causing high dielectric creep stresses
Solution Approach 1:
The second winding is divided into two separate parts (first upper part and second lower part) with an opening between them, allowing the shielding element to stretch continuously between the parts. This segmentation eliminates the need for separate shielding rings while maintaining uniform electrical field distribution and reducing dielectric creep stresses in the insulation.
2Reliability
If the inductive device is designed for high voltage operation, then the insulation capability is sufficient, but the device size becomes large and bulky
Solution Approach 1:
The first winding connection passes through the opening in the axial direction, utilizing the vertical dimension to route conductors through the center of the second winding. This dimensional approach allows for compact arrangement of insulation components and reduces the overall device volume while maintaining adequate insulation distances for high voltage operation.
3Reliability
If insulation is provided through cellulose and transformer oil, then sufficient insulation is achieved, but the design becomes complex to handle assembly and short circuit forces
Solution Approach 1:
The shielding element is integrated with the second winding structure, stretching continuously between the upper and lower parts. This merging of shielding and winding structures simplifies the insulation design by eliminating edge effects and reducing dielectric creep stresses, making the insulation system more robust against assembly and short circuit forces.
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 results in a more compact, reliable, and economical inductive device with reduced dielectric stresses and simplified insulation design, facilitating easier handling and transportation while maintaining high reliability and low losses.
Implementation Method 1
a concentric electric shielding element around the center axis and stretching all the way between the upper and the lower part of the second winding, the shielding element comprising a metal shield layer
Implementation Method 2
a first and second concentric winding wound around a center axis of the inductive device
Data Source
AI summary
An inductive device including a first and second concentric winding wound around a center axis of the inductive device, where the second winding is placed outside of the first winding and provided in two separate parts a first upper part and a second lower part, wherein there is an opening between the first and second parts of the second winding and the first winding has a first winding connection that passes through said opening, the inductive device further including a concentric electric shielding element around the center axis and stretching all the way between the upper and the lower part of the second winding, the shielding element including a metal shield layer.