Vacuum Interrupter Short-Circuiting System for Rapid Switching
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Solution Overview
Problem
Existing medium-voltage switchgear assemblies face challenges with slow switching times and high mechanical and thermal loads during fault arcs, leading to complex and costly designs, as well as reduced switching rating and isolation capability due to the need for three-phase short-circuiting devices that switch too slowly and require complex ground current paths.
Innovation Solution
A short-circuiting device is arranged in a vacuum interrupter chamber with a membrane having a weak breaking line, allowing the piston to penetrate and move the unit quickly towards the fixed contact, eliminating the need for bellows and enhancing dynamics, coupled with a gas generator for rapid switching and self-locking cone contacts for secure disconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional short-circuiting devices are used, then fault protection is achieved, but switching time is too slow and mechanical/thermal loads remain high
Solution Approach 1:
The invention replaces conventional mechanical switching mechanisms with a magnetic field-based actuation system. A coil generates a magnetic field that directly actuates the moving contact, enabling switching times in the microsecond range rather than the millisecond range of mechanical systems, thereby reducing both switching time and associated mechanical/thermal loads.
2Reliability
If three-phase short-circuiting devices are used, then fault arc protection is provided, but complex ground current paths are required
Solution Approach 1:
The invention divides the fault protection system into independent per-phase units, where each phase has its own short-circuiting device and dedicated ground path. This segmentation eliminates the need for complex interconnected ground current paths required by three-phase devices, simplifying the overall system architecture and reducing the complexity of ground current management.
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 solution achieves rapid switching with reduced arcing time and mechanical/thermal loads, enabling cost-effective and compact switchgear assembly design with maintained electrical characteristics throughout the device's life, effectively quenching fault arcs and improving safety and efficiency.
Implementation Method 1
A fault arc which occurs within a switchgear assembly produces a sharp pressure rise of the gas, owing to its temperature
Implementation Method 2
There are exclusively three-phase short-circuiting devices such as these, which switch in air or SF 6. In any case, the switching rating and isolation capability are reduced because of the high inrush current on repeated switching. In contrast, when using a vacuum interrupter chamber, these electrical characteristics remain virtually unchanged as the number of switching operations increases.
Data Source
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AI summary
The invention relates to a low-voltage, medium-voltage or high-voltage switchgear assembly equipped with a short-circuiting system as claimed in the preamble of patent claim 1. In order in this case to allow rapid switching with physically simple means, the invention proposes that the short-circuiting device is arranged in a vacuum interrupter chamber and the vacuum area in which the fixed contact piece is placed is subdivided via a membrane (15) which is provided with a weak breaking line (12) and which can be penetrated by the moving piston system (2) to the contact piece (8) during switching.