The reason for the name of vacuum circuit breakers is that the arc extinguishing and the gap between the contacts after the arc extinguishing are all derived from vacuum insulation. Therefore, vacuum circuit breakers are often used in distribution networks such as frequent operation and long-term arc extinguishing without maintenance. Among them, it plays the role of protection and control of electrical equipment.
Since the circuit breaker is widely installed and used in the medium and high voltage field, its overall performance and requirements will be extremely strict. The functions of the vacuum circuit breaker are as follows.
1. It can improve the insulation tolerance of the vacuum arc extinguishing mechanism:
Because of the needs of environmental conditions, the insulation tolerance between the fractures of the arc extinguishing chamber of the vacuum circuit breaker is specified as the rated voltage, which is very important compared to the relatively high single fracture. At the same time, it also effectively reduces the number of breaks that should be made when the circuit is connected in series, and makes it easier to optimize the structure of the vacuum circuit breaker.
2. Improve the compressive strength between the contacts inside the arc-extinguishing chamber:
We have said before that since the inside of the arc-extinguishing chamber of the circuit breaker is in a high vacuum environment, the gas that will exist between the contacts of the circuit breaker can be said to be very high thin.
Therefore, it will not be subjected to the inter-electrode voltage and the phenomenon of dissociation will occur, but the breakdown event that occurs between the electrodes is often seen in practical applications.In order to improve the pressure resistance of the contact gap of the vacuum circuit breaker, it is necessary to choose a material with a higher melting point or boiling point, a relatively small thermal conductivity, and a higher mechanical strength and hardness.
3. Improve the insulation recovery ability between the contact poles after the vacuum circuit breaker breaks the current:
In general, the short-circuit breaking circuit is worth paying attention to after the arc current crosses zero.The speed of the insulation recovery in the contact gap determines whether the arc will reignite. If it is faster than the transient recovery voltage of the contact gap, it can achieve successful disconnection.
4. It can strengthen the external insulation performance of the arc extinguishing chamber:
The insulator made of epoxy resin can wrap the ceramic shell surface of the arc extinguishing mechanism in the vacuum circuit breaker, thereby achieving the effect of insulation strengthening and improving the pollution resistance performance.