How does a sealed vacuum circuit breaker achieve efficient arc extinguishing?
Publish Time: 2025-02-07
The way sealed vacuum circuit breaker achieves efficient arc extinguishing mainly depends on its special working environment and design principle.
1. The role of vacuum environment
High insulation strength: In a vacuum environment, due to the thin gas molecules, there is almost no effective collision, so it has a high insulation strength. This makes the vacuum gap show higher insulation performance than high-pressure air and SF6 gas at a smaller contact gap.
Strong arc extinguishing ability: In a vacuum environment, the formation and maintenance of the arc become difficult. When the contacts are separated, the arc generated is difficult to maintain in a vacuum because there is a lack of sufficient medium to support the burning of the arc. Therefore, the arc will be extinguished quickly.
2. Contact design and arc extinguishing
Contact material: The contacts of sealed vacuum circuit breaker are usually made of high melting point metal materials, such as copper tungsten alloy. These materials have good conductivity and high temperature resistance, and can maintain stable mechanical strength and electrical properties at high temperatures.
Contact shape and structure: The contacts are usually designed in special shapes, such as contacts with spiral grooves. This design can increase the rotational movement of the arc on the contact surface, making the arc more dispersed and accelerating its cooling and extinguishing process. At the same time, the contact gap is also precisely controlled to ensure that sufficient insulation strength can be quickly generated when breaking.
3. Magnetic field effect and arc movement
In sealed vacuum circuit breakers, magnetic fields are sometimes used to control the movement and extinguishing process of the arc. For example, by setting a magnetic field coil near the contact or using the magnetic field generated by the arc itself, the arc can be deflected or rotated by the electromagnetic force. This movement helps to increase the contact area between the arc and the surrounding medium and accelerate the cooling and extinguishing of the arc.
4. Other auxiliary measures
In addition to the above main principles, sealed vacuum circuit breakers may also adopt some auxiliary measures to improve the arc extinguishing efficiency. For example:
Arcing chamber design: The arc extinguishing chamber is usually designed with a special shape and structure to optimize the arc extinguishing process. For example, the inner wall of the arc extinguishing chamber may be coated with a special arc extinguishing material or a composite insulation structure.
Gas filling: Although vacuum circuit breakers mainly rely on vacuum environment to extinguish arcs, in some cases, in order to further improve the arc extinguishing performance, a small amount of inert gas or other special gases may be filled in the arc extinguishing chamber. These gases can affect the burning characteristics and extinguishing speed of the arc.
In summary, sealed vacuum circuit breakers achieve the goal of efficient arc extinguishing by combining the high insulation strength and arc extinguishing ability of the vacuum environment, specially designed contact shape and structure, magnetic field effect, and auxiliary measures. This makes sealed vacuum circuit breakers have broad application prospects and important value in power systems.
