Medium-Voltage Switchgear Layout With Vacuum Arc Interruption
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Solution Overview
Problem
Existing load-break switches for medium voltage electric systems face challenges in achieving high-level dielectric insulation and arc-quenching capabilities while maintaining structural compactness and environmental sustainability, with traditional solutions using SF6 gas being environmentally harmful and alternative designs offering poor performance.
Innovation Solution
A switching apparatus with electric poles featuring a movable contact system and vacuum interrupters, arranged to ensure dielectric insulation and arc-quenching capabilities, while optimizing structural compactness and using environment-friendly gases like dry air or gas mixtures.
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 greenhouse gas emissions
Solution Approach 1:
The patent changes the physical state parameters of the insulating medium from gaseous SF6 to liquid dielectric oil, fundamentally altering the medium's properties to achieve both environmental sustainability and superior electrical performance. The liquid state provides enhanced dielectric strength and arc-quenching capabilities while eliminating greenhouse gas emissions.
Solution Approach 2:
The patent creates an inert liquid dielectric environment that suppresses arc formation and provides excellent insulation. The liquid medium forms an arc-resistant atmosphere that automatically extinguishes arcs through cooling and deionization, replacing the harmful gaseous SF6 atmosphere with an environmentally friendly alternative.
2Reliability
If separate contact arrangements for current carrying and arc-quenching are used, then high-level arc-quenching capabilities are achieved, but device complexity increases
Solution Approach 1:
The patent designs contacts that simultaneously perform multiple functions: current conduction, arc attachment, and arc quenching. The same contact structure serves as both the electrical conductor and the arc-quenching element, eliminating the need for separate specialized components and simplifying the overall device architecture.
Solution Approach 2:
The patent merges the current-carrying function and arc-quenching function into a single integrated contact system. The contacts are designed to handle both normal current flow and arc extinction in one unified structure, reducing the number of parts and simplifying the mechanical arrangement.
3Reliability
If traditional contact arrangements are used, then reliable current carrying is achieved, but structural compactness deteriorates
Solution Approach 1:
The patent transitions from a horizontal arrangement of contacts to a vertical configuration where contacts are stacked along the vertical axis. This dimensional change allows the same functional elements to be packed more efficiently, reducing the horizontal footprint and improving structural compactness while maintaining current carrying reliability.
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 apparatus achieves high-performance dielectric insulation and arc-quenching with reduced size and cost, facilitating easy industrial production and environmental compliance.
Implementation Method 1
a vacuum interrupter, which comprises a fixed arc contact electrically connected to the first pole terminal and 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 further comprises a vacuum chamber, in which the fixed arc contact and the movable arc contact are enclosed and are coupled or decoupled.
Implementation Method 2
the switching apparatus ensures high-level performances in terms of dielectric insulation and arc-quenching capabilities during the current breaking process
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, 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 further comprises a vacuum chamber, in which the fixed arc contact and the 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 a contact shaft solidly coupled to the movable arc contact. 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.