Permanent Magnet Arc Quenching in Gas-Insulated Switchgear
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Solution Overview
Problem
Existing load-break switches for gas-insulated switchgear face challenges in achieving a simple and cost-effective design with high switching capacity, particularly in effectively managing arcs during contact opening and preventing re-ignition.
Innovation Solution
A permanent magnet system is galvanically connected to the outside of the fixed contact arrangement between specific limit positions, allowing the arc to transfer to the magnet system, which is positioned at an optimal angle and enclosed by a conductive casing to facilitate arc quenching, and a follow-on contact ensures the arc burns between the magnet and the contact, preventing material removal on the fixed contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If permanent magnets are integrated into the fixed contact arrangement, then arc quenching effectiveness is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The permanent magnet system is extracted from the fixed contact arrangement and mounted separately on the switching shaft. This allows the magnetic field generation function to be separated from the contact system, simplifying the overall structure while maintaining arc quenching effectiveness. The permanent magnets are positioned independently to create the necessary magnetic field without being integrated into the contact components themselves.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the permanent magnets and the arc. The permanent magnets generate a magnetic field that acts on the arc to deflect it toward the arc extinction plates, rather than directly contacting the fixed contacts. This intermediary magnetic field enables arc control without requiring permanent magnets to be physically integrated into the contact arrangement.
2Productivity
If permanent magnets are positioned to effectively quench arcs, then switching capacity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The arc quenching function is segmented into multiple arc extinction plates positioned at different locations around the switching shaft. The permanent magnets are arranged to create magnetic fields that affect different portions of the arc path. This segmentation allows each magnet and plate to be positioned with standard tolerances while collectively achieving effective arc quenching across the entire arc path.
Solution Approach 2:
The patent optimizes parameters such as the number of permanent magnets, their radial distance from the switching shaft, and their angular positions to maximize arc quenching effectiveness. By carefully selecting these parameters within standard manufacturing tolerances, the design achieves high switching capacity without requiring ultra-precise positioning. The magnetic field strength and distribution are tuned to work effectively with conventional manufacturing capabilities.
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 quenches the arc, preventing re-ignition and ensuring high switching capacity with a simple, cost-effective design by utilizing the magnetic field to direct the arc away from the fixed contact, thus enhancing the reliability and longevity of the switchgear.
Implementation Method 1
a permanent magnet system associated with the fixed contact arrangement, each with a single permanent magnet for each fixed contact of the fixed contact arrangement
Implementation Method 2
an arc that occurs when the contact system is opened to be shifted in such a way that an arc foot point is shifted to a shadow position on the fixed contact arrangement by magnetic blowing
Implementation Method 3
an arc that occurs when the contact system is opened
Implementation Method 4
an interaction of the arc with the magnetic field of the permanent magnet system
Data Source
Figure 1
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Figure 3~5
AI summary
According to the invention, a load interrupter for an encapsulated, gas-insulated switchgear comprising at least one contact system with a fixed contact arrangement and a moving contact arrangement and a permanent magnet system provided on the fixed contact may be produced having a high switching capacity whilst being simple and economical of construction, by means of fixing the permanent magnet system externally to the fixed contact arrangement with an electrical connection such that on opening the load interrupter the arc which occurs runs to the permanent magnet system.