Arc-Breaking Plate Shielding for Low-GWP Grid Switchgear
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Solution Overview
Problem
Existing switching apparatuses for electric power distribution grids face inefficiencies in arc-quenching processes, particularly at high operating voltages, and are costly to manufacture, especially when using insulating gases with lower global warming potential but weaker dielectric properties.
Innovation Solution
The apparatus incorporates an arc-breaking assembly with stacked arc-breaking plates made of ferromagnetic material and shielding means of insulating material, which guide electric arcs along predictable paths to enhance quenching and cooling, while being cost-effective to produce.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If arc-breaking plates made of ferromagnetic material are used, then arc-quenching efficiency is improved, but manufacturing cost increases
Solution Approach 1:
The arc-breaking assembly is divided into multiple discrete arc-breaking plates arranged in a stack, each plate independently contributing to arc quenching. This segmentation allows the use of ferromagnetic material only where most needed for arc interaction, rather than requiring expensive plastic nozzle arrangements throughout the entire arc chamber, thus reducing overall manufacturing cost while maintaining high arc-quenching efficiency.
Solution Approach 2:
Ferromagnetic arc-breaking plates serve as intermediary elements between the electric contacts and the insulating gas. These plates concentrate and guide the magnetic field generated during arcing, enhancing the quenching effect without requiring the complex plastic nozzle structures used in self-blast circuit breakers, thereby achieving cost-effective arc control.
2Object-affected harmful factors
If insulating gases with lower global warming potential are used, then environmental impact is reduced, but dielectric properties deteriorate
Solution Approach 1:
The invention converts the potentially harmful effect of weaker dielectric properties into a benefit by designing an arc-breaking assembly that actively manages arc behavior. The ferromagnetic plates create strong magnetic fields during arcing that confine and cool the arc plasma, effectively compensating for the reduced dielectric strength of environmentally friendly insulating gases, thus turning a disadvantage into an advantageous arc control mechanism.
Solution Approach 2:
The invention changes the physical parameters of the arc plasma through the magnetic field generated by ferromagnetic plates during arcing. By manipulating magnetic field strength, arc confinement, and plasma cooling rates, the system compensates for the weaker dielectric properties of low-GWP insulating gases, maintaining reliable arc quenching performance despite using environmentally friendly gases.
3Reliability
If plastic nozzle arrangements are used for arc quenching, then arc-quenching efficiency is improved, but manufacturing cost increases significantly
Solution Approach 1:
The invention replaces expensive, complex plastic nozzle arrangements with simpler, more cost-effective ferromagnetic arc-breaking plates. These plates are relatively inexpensive to manufacture from ferromagnetic materials and can be easily replaced if needed, providing a cost-effective alternative to permanent plastic nozzle structures while maintaining effective arc quenching through magnetic field interaction.
Solution Approach 2:
The invention substitutes the mechanical plastic nozzle arrangement (which relies on physical geometry to direct and cool arcs) with a magnetic field-based system using ferromagnetic plates. This substitution eliminates the need for complex plastic molding and assembly, reducing manufacturing costs while achieving arc control through electromagnetic interactions.
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 improved arc-quenching efficiency and commutation performance, reducing manufacturing costs and enhancing the use of environmentally friendly insulating gases.
Implementation Method 1
a plurality of arc-breaking plates (40a, 40b, 40c) arranged in a stacked configuration, in proximal position with respect to the fixed contact (2) and made of a ferromagnetic material
Implementation Method 2
arc-breaking plates made of a metallic ferromagnetic material... favour the quench of the electric arcs by splitting these latter in smaller portions
Implementation Method 3
insulating gases having lower global warming potential but weaker dielectric properties... favour the quench of the electric arcs
Implementation Method 4
arc-chambers provided with nozzle arrangements made of a plastic material (PTFE), which favour the arc-quenching process by causing local overpressures of the insulating gas during arching phenomena
Implementation Method 5
employing the ablation of plastic material at hot temperatures
Implementation Method 6
causing local overpressures of the insulating gas during arching phenomena
Data Source
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AI summary
A switching apparatus for electric power distribution grids comprising: - one or more electric poles; - for each electric pole, at least a fixed contact and a movable contact, said movable contact being reversibly movable between a coupled position, at which said movable contact is coupled to said fixed contact, and an uncoupled position, at which said movable contact is separated from said fixed contact; - for each electric pole, an arc-breaking assembly comprising a plurality of arc-breaking plates arranged side by side and spaced one from another; Said arc-breaking assembly comprises shielding means of electrically insulating material operatively coupled to said fixed contact and to said arc-breaking plates. Said shielding means partially cover surfaces of said fixed contact and said arc-breaking plates, which are exposed to possible electric arcs, during an opening manoeuvre of said switching apparatus.