Vacuum circuit breaker has a high insulating medium for arc extinction as compared to the other circuit breaker. The pressure inside the vacuum interrupter is approximately 10-4 torrent and at this pressure, very few molecules are present in the interrupter. The vacuum circuit breaker has mainly two phenomenal properties.
The outer envelope of vacuum circuit breaker is made up of glass because the glass envelope help in the examination of the breaker from outside after the operation. If the glass becomes milky from its original finish of silvery mirror, then it indicates that the breaker is losing vacuum.
Current chopping in vacuum circuit breaker depends on the vapour pressure and the electron emission properties of the contact material. The chopping level is also influenced by the thermal conductivity–lower the thermal conductivity, lower is the chopping level.
It is possible to reduce the current level at which chopping occurs by selecting a contact material which gives out sufficient metal vapour to allow the current to come to a very low value or zero value, but this is rarely done as it affects the dielectric strength adversely.
Measures to prevent overvoltage. Vacuum circuit breaker has good breaking performance. Sometimes when breaking inductive load, high overvoltage is generated at both ends of inductance due to rapid change of loop current. Therefore, for dry-type transformers and other equipment with low impulse voltage resistance, it is best to install overvoltage protection devices, such as metal oxide arresters.
1. The operating mechanism is small, the overall volume is small, and the weight is light.
2. The contact part is a completely sealed structure, which will not reduce its performance due to the influence of moisture, dust, harmful gases, etc., and it works reliably with stable on-off performance.
3. With multiple reclosing function, it is suitable for the application requirements in distribution network.