Feedthrough Shielding Ring for Compact Dry-Type Transformer Insulation
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Solution Overview
Problem
Dry-type transformers with externally grounded shielding face challenges in maintaining safe electrical distances due to the need for long post insulators, which can be impractical in space-constrained installations, especially at high voltages.
Innovation Solution
A disc-shaped shielding ring made of insulating material is arranged on a tapering section of the post insulator, fixed in a form-fitting manner using a pressed part, providing a gapless and easy-to-attach insulation solution that reduces the length of the post insulator required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If long post insulators are used to maintain safe electrical distances at high voltages, then dielectric strength is improved, but installation space requirements increase
Solution Approach 1:
The shielding ring extends radially outward from the post insulator, creating an additional dimensional barrier against breakdown. This radial insulation surface adds dielectric protection without increasing the axial length of the post insulator, effectively resolving the contradiction between dielectric strength and installation space by utilizing a different spatial dimension.
Solution Approach 2:
The shielding ring acts as an intermediary insulating element positioned between the post insulator and the transformer tank wall. This intermediate structure provides the necessary dielectric strength while allowing the post insulator itself to remain compact, thus maintaining electrical safety without requiring excessive installation space.
2Adaptability or versatility
If the post insulator length is reduced to save space, then installation flexibility is improved, but electrical insulation reliability deteriorates
Solution Approach 1:
By extending insulation in the radial direction through the shielding ring rather than relying solely on axial length, the system maintains electrical insulation reliability while allowing the post insulator to be shorter and more adaptable to various installation configurations.
Solution Approach 2:
The bushing system combines the post insulator material with the shielding ring material (epoxy resin glass fiber reinforced plastic) to create a composite insulation structure. This composite approach provides enhanced dielectric strength that allows for reduced post insulator length while maintaining reliability.
3Reliability
If additional insulating surfaces are added to prevent breakdown, then dielectric strength is improved, but device complexity increases
Solution Approach 1:
The shielding ring is integrated with the post insulator assembly as a unified bushing system. The ring is positioned to enclose the post insulator and is secured through their mutual interaction, merging two functional elements into a single coordinated structure that provides enhanced insulation without proportionally increasing complexity.
Solution Approach 2:
The shielding ring serves multiple functions: it provides radial insulation to prevent breakdown, structurally supports the post insulator assembly, and can be designed to accommodate connection arrangements. This multi-functionality justifies the addition of the element while minimizing net complexity increase.
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 configuration allows for a more compact and flexible installation of dry-type transformers by reducing the length of post insulators, ensuring safe electrical distances and easy access for connections while maintaining high dielectric strength.
Implementation Method 1
a disc-shaped shielding ring which is made of an insulating material and encloses the post insulator flush
Implementation Method 2
fixed in a form-fitting manner by means of a pressed part screwed to a connection surface of the post insulator
Data Source
Figure 1~3
AI summary
A feedthrough system (1) for connecting a dry-type transformer (38) with an external grounded shield (40), comprising a substantially circular cylindrical support insulator (2) with an inner conductor (4) passing through the shield (40), is intended to allow, on the one hand, a breakdown-proof operation and, on the other hand, a particularly space-saving design of a dry-type transformer. For this purpose, the feedthrough system (1) includes a disc-shaped shielding ring (22) made of an insulating material, which flush encloses the support insulator (2).