Gas-Insulated Switchgear Magnetic Layout for Arc Terminal Protection
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Solution Overview
Problem
Existing gas-insulated switchgear designs face issues where arcs during current interruption can damage current-conduction terminals due to the magnetic field deformation caused by closely positioned permanent magnets and magnetic bodies, leading to potential damage of components at the outer periphery of movable-side electrodes.
Innovation Solution
The design incorporates a permanent magnet and a concentrically arranged ferromagnetic body to create a uniform magnetic field, directing the arc away from the current-conduction terminal by applying a Lorentz force that prevents the arc from contacting or melting the terminal, using neodymium, samarium-cobalt, or ferrite magnets and iron alloys to manage the magnetic field effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a permanent magnet and magnetic body are provided closely to each other to strengthen the magnetic field for arc interruption, then the arc interruption performance is improved, but the magnetic field deforms and causes arcs to move to the vicinity of the movable-side electrode outer periphery, damaging components such as current-conduction terminals
Solution Approach 1:
The patent applies local quality by creating different magnetic field strengths in different spatial regions. A first magnetic body is positioned to generate a strong magnetic field in the arc generation region between contacts for effective arc interruption, while a second magnetic body is positioned to generate a weaker magnetic field in the region near the movable-side electrode outer periphery where current-conduction terminals are located. This spatial variation in magnetic field quality prevents arc distortion and component damage while maintaining effective arc interruption.
2Reliability
If SF6 gas is used as insulation gas for excellent insulation property and interruption performance, then electromagnetic induction current can be interrupted by plain breaking, but SF6 gas is a greenhouse gas with very high global warming potential and discharge is restricted
Solution Approach 1:
The patent applies parameter changes by transitioning from SF6 gas to alternative insulation gases such as dry air, CO2, or N2 that have lower global warming potential. To compensate for the reduced interruption performance of these alternative gases, the patent introduces a magnetic field generation mechanism using permanent magnets and magnetic bodies to create a magnetic field that enhances arc interruption capability, thereby maintaining reliable circuit breaking function while using environmentally friendly insulation gas.
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 configuration effectively prevents damage to the current-conduction terminal by ensuring the arc is rotated and contained away from the terminal, maintaining the integrity and performance of the switchgear components.
Implementation Method 1
a permanent magnet generating a magnetic field on an arc to extinguish the arc
Implementation Method 2
an electromagnetic force between current flowing in the arc and a magnetic field perpendicular to the arc
Implementation Method 3
a magnetic body is provided near the magnet so as to strengthen a magnetic field generated by the magnet
Implementation Method 4
a closed loop is formed, so that a magnetic flux due to currents of normal phases of the same lines and currents of other normal lines interlinks and electromagnetic induction current flows
Data Source
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AI summary
A gas-insulated switchgear (1) includes, inside an airtight container with insulation gas sealed therein, a fixed-side electrode (11), and a movable-side electrode (12) which is driven by a driving mechanism attached to the airtight container so as to contact/separate with/from the fixed-side electrode (11), the gas-insulated switchgear (1) including: a first magnetic body provided on an inner side from an outer periphery of the fixed-side electrode (11); a second magnetic body having a tubular shape and surrounding the fixed-side electrode (11); and a current-conduction terminal (15) provided at an outer periphery of the movable-side electrode (12), wherein at least one of the first magnetic body and the second magnetic body is a magnet magnetized in a direction in which the movable-side electrode (12) is movable.