HV/MV Switch Contact Assembly With Gas Channels for Arc Quenching
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Solution Overview
Problem
Existing Medium Voltage switches face challenges in achieving a compact design with fast closing and opening operations while minimizing arching phenomena, especially with the transition from SF6 to alternative insulating gases.
Innovation Solution
A contacts arrangement for High and Medium Voltage switches, featuring a movable contact assembly with a first longitudinal channel housing a central contact pin and transversal channels that convey an arc suppression gas to control arc phenomena during opening operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SF6 gas is used for insulation and arc-quenching, then dielectric insulation and arc-quenching capabilities are excellent, but environmental harm increases due to potent greenhouse gas effects
Solution Approach 1:
The patent changes the chemical composition parameter of the insulating gas from SF6 to alternative gases (such as dry air, nitrogen, or fluorinated compounds with lower GWP), thereby maintaining electrical insulation performance while reducing environmental harm. The gas composition is specifically tailored to provide adequate dielectric strength and arc-quenching properties without using potent greenhouse gases.
2Object-affected harmful factors
If alternative insulating gases (e.g., pressurized dry air) are used instead of SF6, then environmental harm is reduced, but dielectric insulation and arc-quenching capabilities deteriorate
Solution Approach 1:
The patent applies local quality by creating a pre-arching contact element with specific geometric features (protruding terminal portion, longitudinal channel, transversal channels) that concentrate and direct the alternative insulating gas precisely where the arc forms. This localized gas delivery enhances arc-quenching effectiveness at the contact interface, compensating for the inherently lower arc-quenching capability of alternative gases compared to SF6.
Solution Approach 2:
The patent utilizes pneumatic principles by employing pressurized alternative insulating gases delivered through controlled channels (transversal channels in the pre-arching contact element). The gas flow is directed along the arc path to extinguish the arc, using fluid dynamics to achieve effective arc quenching despite the lower dielectric strength of alternative gases compared to SF6.
3Volume of moving object
If a compact design is implemented, then device size is reduced, but arc suppression capabilities and operational functionality may be compromised
Solution Approach 1:
The patent applies nesting by placing the longitudinal channel inside the pre-arching contact element, which itself is integrated into the movable contact assembly. The transversal channels are embedded within the longitudinal channel structure, creating a compact nested arrangement that delivers arc suppression gas efficiently without requiring additional external space, thus maintaining compact overall switch design.
Solution Approach 2:
The patent uses dimensional optimization by configuring the transversal channels to deliver gas in a direction perpendicular to the contact separation motion, creating a three-dimensional arc suppression pattern that effectively covers the arc path. This spatial arrangement maximizes arc quenching efficiency within a compact volume by utilizing multiple spatial dimensions for gas delivery.
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 enables efficient arc control and enhances the switch's functionalities, including breaking capabilities, suitable for high nominal operating voltages and currents, while maintaining a compact design compatible with modern switchgears using alternative insulating gases.
Implementation Method 1
transversal channels which convey an arc suppression gas from the outside of the main contact element of the movable contact assembly into said first longitudinal channel
Implementation Method 2
arc suppression gas... adapted for housing the central contact pin... conveying an arc suppression gas... to control arc phenomena during opening operations
Data Source
AI summary
A switch contacts arrangement comprising a fixed assembly and a movable assembly couplable to said fixed assembly between a closed/open position. The fixed assembly comprises: a main contact group and a pre-arching contact element comprising a central contact pin centrally positioned in a contact seat and having a terminal portion protruding outside said contact seat. The movable assembly comprises a main contact element having a body with a contact end configured to be inserted into said contact seat with a movement, the external surface of said contact end in electrical contact with said main contact elements when inserted into said contact seat. The contact end comprises an opening and a longitudinal channel for housing the central contact pin and further comprises one or more transversal channel(s) conveying a quenching gas from the outside of the main contact element into said longitudinal channel during the opening operation of said movable assembly.