What is a vacuum circuit breaker and what is the difference between it and an ordinary circuit breaker?

A vacuum circuit breaker is a kind of switchgear widely used in power systems. It is used in many aspects due to its advantages of small size and is suitable for frequent operation. The following editor will give you specific knowledge related to it, mainly including what is a vacuum circuit breaker, the working principle of a vacuum circuit breaker, the function of a vacuum circuit breaker, and the difference between a vacuum circuit breaker and an ordinary circuit breaker.

 1  What is a vacuum circuit breaker?

For novices in decoration, they may not even know this basic question. Therefore, before using the vacuum circuit breaker, some homework must be done in order to facilitate the correct use later.
Vacuum circuit breakers are named for their arc extinguishing medium and the insulation medium of the contact gap after arc extinguishing are both high vacuum and are widely used in distribution networks.
Vacuum circuit breakers can usually be divided into multiple voltage levels, and the low-voltage type is generally used for explosion-proof electrical applications, such as coal mines and so on. Its rated current reaches 5000A, the breaking current reaches a better level of 50kA, and has been developed to a voltage level of 35kV.

 2  Working principle of vacuum circuit breaker

After knowing what a vacuum circuit breaker is, it is also necessary to understand the working principle of the vacuum circuit breaker, so that it can be more reasonably applied in the power system.
When the static and moving contacts are opened under the action of the operating mechanism, an arc is generated between the contacts, and the surface of the contacts volatilizes steam at high temperatures. Because the contacts are designed in a special shape, a magnetic field is generated when the current passes, and the arc is here. Under the action of the magnetic field, it moves quickly along the tangential direction of the contact surface, and part of the metal vapor condenses on the metal cylinder (shield), and the arc is extinguished when it naturally crosses zero, and the medium speed between the contacts quickly recovers.

 3  Function of vacuum circuit breaker

(1) Improve the insulation resistance of the vacuum interrupter
Vacuum circuit breakers should be developed in the field of high-voltage use, and the insulation resistance between the gaps of vacuum interrupters should be improved. The economic significance of making a single-fracture vacuum interrupter with a higher-rated voltage is huge. It can not only reduce the number of series fractures but also make the structure of the circuit breaker simple, thereby improving the reliability of the equipment and reducing the cost of the equipment accordingly.

(2) Improve the insulation recovery speed between the contact poles after breaking the current
After the vacuum circuit breaker is used, the key to the success of breaking the circuit and breaking the current is that after the arc current crosses zero, the insulation recovery speed of the contact gap is faster than the transient recovery voltage speed between the contact gaps, so that there will be no re-ignition. achieve successful breaking.

(3) Improve the compressive strength between contacts in the vacuum interrupter
When the vacuum gap actually breaks down, several mechanisms may work at the same time, and there is always free gas in the breakdown path, which is provided by the metal vapor generated after the voltage is applied or the adsorbed gas is released by the contact. After the vacuum circuit breaker is used, the pressure resistance performance of the contact gap of the vacuum interrupter can be improved.

 4  The difference between a vacuum circuit breaker and an ordinary circuit breaker

(1) Differences in voltage levels
Generally, the applied voltage level of the air switch is below 500, while the vacuum circuit breaker can usually be applied to various voltage levels above 220T.
(2) The ability to interrupt the current is different
Vacuum circuit breakers can withstand a larger load and short-circuit current than ordinary vacuum air switches.

Ordinary low-voltage circuit breakers use the air side to blow out the arc. Vacuum circuit breakers are generally used in high-voltage system circuit breakers. Both are used to break the circuit, the voltage of the two breaking lines is different, the magnitude of the current is different, and the principle of arc extinguishing is different.

What is a vacuum circuit breaker, the working principle of a vacuum circuit breaker, the function of a vacuum circuit breaker, and the difference between a vacuum circuit breaker and an ordinary circuit breaker, this is the introduction here! Thanks for reading everyone! Hope to be helpful to everyone!