Integrated Shielded Bushing for Medium-Voltage Flashover Control
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Solution Overview
Problem
In medium voltage switchgear, flashovers occur due to high field intensity, leading to increased costs and installation complexities from the requirement of additional covers for bushings, which also occupy more space and time.
Innovation Solution
A bushing system with a polyamide hollow body and a metal holder piece that integrates a shield and a T-off bar connection, eliminating the need for separate shielding covers by mechanically fixing the T-off bar and acting as an electrical field-forming component, reducing partial discharges and assembly time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate shielding covers are used to protect against flashovers, then flashover protection is improved, but device complexity and installation time increase
Solution Approach 1:
The holder piece is merged with the shielding function by integrating a shield element directly into the holder piece structure. This allows the holder piece to simultaneously perform mechanical support (holding the T-off bar) and electrical field control (shielding against flashovers), eliminating the need for separate shielding covers and reducing overall device complexity
Solution Approach 2:
The holder piece is designed as a multi-functional component that combines mechanical support functions (fixing the T-off bar to the bushing) with electrical field control functions (providing shielding through the integrated shield). This universal component replaces multiple separate components, simplifying the overall bushing structure while maintaining flashover protection
2Reliability
If separate shielding covers are used for flashover protection, then flashover protection is improved, but installation time increases
Solution Approach 1:
By combining the shielding function into the holder piece, the number of separate components is reduced, which directly decreases assembly steps and installation time. The integrated design allows for simpler mounting procedures compared to installing separate shielding covers
3Reliability
If separate shielding covers are used, then flashover protection is improved, but space requirements increase
Solution Approach 1:
The shield is integrated into the holder piece structure, eliminating the need for additional external shielding covers. This reduces the overall space occupied by the bushing assembly while maintaining the necessary flashover protection through the compact integrated shield design
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 reduces partial discharges, simplifies assembly, and saves material costs by integrating the holder piece with the bushing, enhancing dielectric performance and reducing the need for additional shielding covers.
Implementation Method 1
the shield of the holder piece is located adjacent to a part of the T-off bar when the T-off bar is connected to the second end of the hollow body... to lower the field intensity in critical points
Implementation Method 2
The hollow body comprises polyamide... Bushings allow current flow between metal-clad switchgear through compartments
Data Source
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AI summary
The present invention relates to a bushing for a metal clad medium voltage switchgear, the bushing comprising: - a hollow body (4); and - a holder piece (2); wherein the hollow body comprises polyamide; wherein the holder piece comprises at least one metal; wherein the holder piece comprises a body part and a shield (5); wherein a first end of the hollow body is configured to connect to a compartment of a medium voltage switchgear; wherein the holder piece is configured to connect a T-off bar (3) to a second end of the hollow body; wherein the hollow body has an axis down the centre of the hollow body from the first end to the second end; and wherein the shield of the holder piece is located adjacent to a part of the T-off bar when the T-off bar is connected to the second end of the hollow body.