Vacuum Interrupter Shield Element Stress Reduction
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Solution Overview
Problem
Existing shield elements for vacuum interrupters induce mechanical stresses during the closure soldering process, leading to cracks in electrically insulating regions and potential vacuum breakdown, especially in high-voltage applications.
Innovation Solution
A shield element with a connection region, a shield inner region, and a shield outer region, featuring U-shaped structures that reduce mechanical stresses by optimizing the arrangement and contact points between conductive and insulating wall elements, preventing stress-induced fractures during cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shield element is used for field control and protection during closure soldering, then the vacuum interrupter is protected from vaporized metal deposition and field control is improved, but mechanical stresses are induced during cooling that cause cracks in electrically insulating regions
Solution Approach 1:
The shield element features a connection region with specific local structural characteristics (first and second structures) that differ from the shield inner and outer regions. This local quality variation allows the connection region to specifically address stress concentration issues at the interface between conductive and insulating wall elements, while maintaining the protective function in other regions.
Solution Approach 2:
The shield element is divided into distinct functional regions: a connection region with first and second structures, a shield inner region, and a shield outer region. This segmentation allows each region to be optimized for its specific function - the connection region for stress reduction and the shield regions for field control and protection.
2Reliability
If the shield element has a large outer diameter (over 200 mm) for high-voltage applications, then field control capability is improved, but the complexity of the structure and difficulty of manufacturing increase
Solution Approach 1:
The shield element utilizes parameter changes in the connection region, specifically the configuration of the first and second structures with their respective openings facing opposite directions. This structural arrangement allows for stress management without requiring excessive complexity, even for large-diameter shield elements used in high-voltage applications over 140 kV.
3Strength
If the first structure and second structure are designed to contact the end face of the electrically insulating wall element without contacting the inner or outer sides, then stress distribution is optimized, but the precision of manufacturing and assembly increases
Solution Approach 1:
The first structure and second structure act as intermediary elements between the conductive wall element and the insulating wall element. By contacting only the end face and not the inner or outer sides, they mediate the stress transfer in a controlled manner, distributing stresses more evenly without requiring extremely tight tolerances for assembly.
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 shield element effectively minimizes mechanical stresses during soldering and cooling, reducing the risk of cracks in electrically insulating regions, thereby maintaining vacuum integrity and switching capability in high-voltage vacuum interrupters.
Implementation Method 1
induced mechanical stresses can occur, in particular during cooling after closure soldering in the vacuum furnace
Data Source
AI summary
A shield element for a vacuum interrupter for installation between an electrically conductive wall element and an electrically insulating wall element of a vacuum interrupter includes a connection region, a shield inner region and a shield outer region. The shield outer region can be disposed outside of and the shield inner region can be disposed within the vacuum interrupter. The connection region has a first structure and a second structure which prevent the formation of mechanical stresses after soldering of the vacuum interrupter. A vacuum interrupter, a method for producing a shield element and a method for producing a vacuum interrupter are also provided.