Bus Bar Assembly Creepage Distance via Etched Metallization
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Solution Overview
Problem
Bus bar assemblies experience partial discharge due to trapped air voids, leading to material breakdown, as high field strength concentrates in small air voids between conductors and insulator layers, necessitating a solution to reduce this occurrence.
Innovation Solution
A bus bar assembly with a plated insulator member having conductor layers on its surfaces, where the metallization is etched back to create a sufficient creepage distance, eliminating air voids and ensuring both surfaces are at the same potential, thereby preventing partial discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If air voids are trapped between conductors and insulator layers, then the bus bar assembly is easier to manufacture, but partial discharge occurs leading to material breakdown
Solution Approach 1:
The patent removes air voids from the interface between conductors and insulator layers by applying metallization that extends beyond the insulator edges. This extraction of harmful air pockets eliminates the medium necessary for partial discharge, thereby improving reliability while maintaining manufacturing simplicity through conventional plating processes.
Solution Approach 2:
The metallization layer serves as an intermediary element that bridges the conductor and insulator while extending beyond the insulator edges. This intermediary structure prevents direct contact between air and the high-field region at the conductor-insulator interface, eliminating partial discharge pathways without complicating the manufacturing process.
2Power
If high field strength is used in dielectric insulator, then power distribution capability is improved, but partial discharge is exacerbated due to field concentration in air voids
Solution Approach 1:
The patent converts the harmful effect of high field strength, which normally concentrates in air voids to cause partial discharge, into a beneficial effect by extending metallization beyond insulator edges. This creates an equipotential surface that redirects the high field strength away from air voids, maintaining power distribution capability while eliminating partial discharge.
Solution Approach 2:
The metallization extending beyond insulator edges creates an equipotential surface that equalizes the electrical potential at the conductor-insulator interface. This eliminates field concentration in air voids by providing a continuous conductive path, allowing high field strength to be maintained for power distribution without triggering partial discharge.
3Reliability
If metallization is extended beyond insulator edges to create creepage distance, then partial discharge is prevented, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies metallization in advance to cover the entire insulator surface and extend beyond its edges before final assembly. This preliminary action ensures that the creepage distance requirement is built into the structure itself, eliminating the need for post-assembly adjustments and reducing precision requirements during final assembly.
Solution Approach 2:
The patent changes the geometric parameters of the metallization layer, extending it beyond the insulator edges by a specific distance to create the required creepage path. This parameter change transforms the insulation structure from a simple sandwich to a multi-layer configuration with built-in partial discharge prevention, maintaining reliability while using conventional manufacturing tolerances.
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 significantly increases the partial discharge inception voltage, reducing the likelihood of detrimental partial discharge and ensuring the bus bar assembly meets creepage distance requirements, thus preventing arcing and material degradation.
Implementation Method 1
Air 10 in the air voids frequently leads to a plasma creation in the air voids known as partial discharge. The partial discharge effect is caused by the high field strength that is used in a dielectric insulator, and is exacerbated by the relative dielectric constant of insulator layer 8 as compared to the dielectric constant of air 10, which causes the field to concentrate in the small air voids.
Implementation Method 2
the metallization is etched back to create a sufficient creepage distance, eliminating air voids and ensuring both surfaces are at the same potential
Data Source
AI summary
A bus bar assembly includes a first main conductor, a second main conductor, and an insulator member provided between the main conductors. The insulator member includes: (i) an insulator component, (ii) a first conductor layer provided on the top surface of the insulator component, and (iii) a second conductor layer provided on the bottom surface of the insulator component, wherein the first conductor layer includes an outer edge around a perimeter thereof, wherein the outer edge is located at least a certain distance from the outer edge around the perimeter of the insulator component, wherein the second conductor layer includes an outer edge around a perimeter thereof, wherein the outer edge is located at least the same certain distance from the outer edge of the insulator component, and wherein the certain distance is sufficient to cause the bus bar assembly to satisfy the creepage requirement of the assembly.