Medium-Voltage Switchgear Vacuum Contact Assembly for SF6-Free Insulation
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Solution Overview
Problem
Traditional load-break switches for medium voltage electric systems face challenges with arc-quenching capabilities and dielectric insulation when using alternative insulating gases instead of SF6, leading to complex designs and poor structural compactness and reliability.
Innovation Solution
A switching apparatus with electric poles that utilize a movable contact assembly with a vacuum chamber and arc contact members, which are decoupled and coupled within the vacuum chamber to improve arc-quenching and dielectric insulation, and a cam mechanism to ensure proper contact alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If alternative insulating gases (pressurized dry air or environment-friendly gases) are used instead of SF6, then environmental impact is reduced, but arc-quenching capabilities and dielectric insulation deteriorate
Solution Approach 1:
The contact assembly is segmented into multiple contact members (first, second, third, and fourth contact members) arranged in series. This segmentation allows each contact member to be optimally positioned and sized for its specific function, improving overall arc-quenching performance and dielectric insulation while using alternative insulating gases.
Solution Approach 2:
The contact members are arranged in a spatial configuration along a longitudinal axis, creating multiple dimensions for arc extinction. The series arrangement of contact members provides extended arc path length in the longitudinal dimension, enhancing arc-quenching capabilities without requiring SF6 gas.
2Object-affected harmful factors
If alternative insulating gases are used, then environmental preservation is improved, but device complexity increases due to complicated contact arrangement solutions
Solution Approach 1:
Multiple contact members are merged into a single integrated contact assembly that rotates as one unit about a rotation axis. This merging simplifies the drive mechanism and reduces the number of separate components, thereby reducing device complexity while maintaining the benefits of alternative insulating gases.
Solution Approach 2:
The rotatable contact assembly serves multiple functions: it provides circuit-breaking functionality through the series arrangement of contact members, enables circuit-disconnecting functionality through rotational movement, and maintains dielectric insulation using alternative gases. This multi-functionality reduces the need for separate mechanisms, simplifying overall device complexity.
3Object-affected harmful factors
If alternative insulating gases are used, then environmental benefits are achieved, but structural compactness deteriorates
Solution Approach 1:
The contact members are nested along a longitudinal axis within a compact rotational assembly. The series arrangement allows contact members to be positioned concentrically or in close proximity, maximizing space utilization and achieving structural compactness while using alternative insulating gases.
Solution Approach 2:
The contact assembly is designed to rotate dynamically about a rotation axis, allowing compact storage of the contact members in a radial or axial configuration. This dynamic design enables the long arc path required for effective arc-quenching to be achieved within a compact volume, maintaining structural compactness while using environmentally-friendly gases.
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 achieves high-level performances in dielectric insulation and arc-quenching, enhances structural compactness and simplicity, and ensures high reliability and ease of industrial production.
Implementation Method 1
a vacuum chamber and a pair of arc contact members that are accommodated within said vacuum chamber
Implementation Method 2
a pair of arc contact members that are accommodated within said vacuum chamber and that can be mutually coupled or decoupled
Data Source
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AI summary
A switching apparatus for medium voltage electric systems, said switching apparatus comprising one or more electric poles and, for each electric pole: - a first pole terminal, a second pole terminal and a ground terminal, said first pole terminal being electrically couplable with a first conductor of an electric line, said second pole terminal being electrically couplable to a second conductor of said electric line and said ground terminal being electrically couplable to a grounding conductor; - a fixed contact assembly including a plurality of fixed contact members spaced one from another; - a movable contact assembly rotatable about a rotation axis between a first end-of-run position (PA), which corresponds to a closed state of said switching apparatus, and a second end-of-run position (Pc), which corresponds to a earthed state of said switching apparatus, said movable contact assembly passing through an intermediate position (PB), which corresponds to an open state of said switching apparatus, when moving between said first and second end-of-run positions. The movable contact assembly is arranged so that, when the switching apparatus is in an open state, the electric contacts within a vacuum chamber of the movable contact assembly are mutually coupled.