Medium-Voltage Switchgear With Vacuum Interrupter Arc Quenching
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Solution Overview
Problem
Traditional load-break switches for medium voltage electric systems face challenges in achieving high dielectric insulation and arc-quenching capabilities while minimizing environmental impact, often resulting in complex designs with poor structural compactness and reliability.
Innovation Solution
A switching apparatus with electric poles featuring a vacuum interrupter and a motion transmission mechanism, utilizing a movable contact and lever arms to manage arc quenching in a vacuum atmosphere, ensuring efficient dielectric insulation and arc-quenching capabilities while maintaining structural simplicity and compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SF6 gas is used for dielectric insulation and arc-quenching, then excellent insulation performance and arc-quenching capabilities are achieved, but environmental harm increases due to SF6 being a powerful greenhouse gas
Solution Approach 1:
The patent replaces SF6 gas with a vacuum environment to achieve dielectric insulation and arc-quenching functions. The vacuum interrupter creates an inert-like environment that eliminates the harmful environmental effects of SF6 while maintaining excellent insulation performance and arc-quenching capabilities through the absence of gas molecules that would otherwise sustain electrical breakdown and arc propagation.
Solution Approach 2:
The patent converts the harmful effect of having no medium (vacuum) into a beneficial property by exploiting the vacuum's inherent ability to provide superior dielectric strength and arc-quenching. The absence of gas molecules, which would normally facilitate electrical breakdown, is transformed into an advantage that enhances insulation performance and rapidly extinguishes arcs when contacts separate.
2Reliability
If multiple contact arrangements are used (one for current carrying, another for arc-quenching), then arc-quenching capabilities are improved, but device complexity increases
Solution Approach 1:
The patent applies multi-functionality by designing the movable contact to perform both current-carrying and arc-quenching functions within a single arrangement. The contact structure is engineered to handle normal current flow during closed state and simultaneously provide effective arc-quenching during opening operations, eliminating the need for separate dedicated contact arrangements for each function.
Solution Approach 2:
The patent merges the functions of current-carrying contacts and arc-quenching contacts into a single integrated contact arrangement. The movable and fixed contacts are designed to work together in both normal operation and arc-extinguishing modes, combining what were traditionally separate functional elements into one unified structure that reduces overall device complexity.
3Reliability
If multiple contact arrangements with different atmospheres are used, then arc-quenching capabilities are improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent uses a vacuum environment within the vacuum interrupter chamber to provide arc-quenching capabilities without requiring separate atmospheric chambers or complex gas management systems. The vacuum atmosphere is maintained through a single hermetically sealed structure, simplifying manufacturing compared to designs that would require multiple atmospheric zones or gas filling procedures.
Solution Approach 2:
The patent combines the arc-quenching function into the same vacuum chamber where the movable and fixed contacts operate, eliminating the need for separate atmospheric environments or additional sealing structures. This integration reduces manufacturing steps, lowers production costs, and simplifies quality control compared to multi-chamber designs.
4Reliability
If complex motion transmission mechanisms are used to coordinate multiple contact arrangements, then operational coordination is improved, but device complexity increases
Solution Approach 1:
The patent applies multi-functionality to the motion transmission mechanism, which simultaneously controls the separation of movable and fixed contacts, manages the opening/closing operations, and coordinates the vacuum interrupter chamber operations. This single mechanism performs multiple coordination tasks that would otherwise require separate control systems, reducing overall device complexity while maintaining reliable operational coordination.
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 provides high-level performances in dielectric insulation and arc-quenching, enhances operational reliability, and allows for cost-effective industrial production, addressing the limitations of existing technologies.
Implementation Method 1
a vacuum interrupter, which comprises a fixed arc contact electrically connected to the first pole terminal, a movable arc contact electrically connected to the fourth fixed contact and reversibly movable along a corresponding translation axis between a coupled position with the fixed arc contact and an uncoupled position from the fixed arc contact. The vacuum interrupter also comprises a vacuum chamber, in which the fixed arc contact and the movable arc contact are enclosed and can be coupled or decoupled.
Data Source
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AI summary
A switching apparatus comprising one or more electric poles. For each electric pole, the switching apparatus comprises a first pole terminal, a second pole terminal and a ground terminal. In operation, the first pole terminal can be electrically coupled to a first conductor of an electric line, the second pole terminal can be electrically coupled to a second conductor of said electric line and the ground terminal can be electrically coupled to a grounding conductor. For each electric pole, the switching apparatus comprises a plurality of fixed contacts spaced apart one from another. Such a plurality of fixed contacts comprises a first fixed contact electrically connected to the first pole terminal, a second fixed contact electrically connected to the second pole terminal, a third fixed contact electrically connected to the ground terminal and a fourth fixed contact electrically connectable with the second fixed contact. For each electric pole, the switching apparatus further comprises a movable contact, which is reversibly movable about a corresponding rotation axis according to opposite first and second rotation directions, so that said movable contact can be coupled to or uncoupled from one or more of the above-mentioned fixed contacts, and a vacuum interrupter comprising a vacuum chamber, in which a fixed arc contact and a movable arc contact are enclosed and can be coupled or decoupled. For each electric pole, the switching apparatus further comprises a motion transmission mechanism operatively coupled to the movable arc contact of said vacuum interrupter. The motion transmission mechanism is actuatable by the movable contact to cause a movement of said movable arc contact along said translation axis, when said movable contact moves about said rotation axis.