To give you a glimpse of the use of vacuum circuit breaker in the switchgears, i will write this article from below parts:
- Features of vacuum circuit breakers
- How to choose the vacuum circuit breaker
- Applications of vacuum circuit breaker
- Examples of vacuum circuit breakers used in switchgears
1. Features of Vacuum Circuit Breakers
Vacuum circuit breakers are widely used in medium voltage switchgears due to its advantages of strong arc extinguishing ability, long electrical life, high technical content, convenient field maintenance. These days vacuum circuit breakers have gradually taken place of traditional oil circuit breaker. Compared with oil circuit breaker, vacuum circuit breaker has stronger insulation, stronger arc extinguishing ability, and smaller contact travel. Because the VCB’s operating mechanism has smaller operation power and the VCB is small and light without noise, the arc extinguishing time is short, the arc energy small and contact loss is small. Therefore the VCB can break off for more times and is suitable for frequent operations. With its long usage life, the contact part does not need to be repaired or inspected during the period of use. Even if the operating mechanism needs maintenance and inspection, the process is very simple.
2. How to choose the vacuum circuit breaker
To choose vacuum circuit breaker, we need to consider from below points:
- Selections of models. Model selections should be based on the rated current value and rated short-circuit current. These two value selection should be based on the actual capacity of the grid. There’s no point picking an interrupting rating much higher than what you actually need as it is not economically feasible and also it will affect the inductive or capacitive current performance of small breaking.
- Selections of environment.
1)Environmental conditions for the use of vacuum circuit breakers
Should meet the requirements of the national standard “AC high-voltage circuit breaker”:
- The altitude does not exceed 1000m.
- The second is that the upper limit of the ambient temperature is not higher than40℃, the lower limit is not lower than 5℃ for indoor products, and not lower for outdoor products At -40℃; indoor products in high-cold areas should not be lower than -25℃The product should not be lower than -40℃. Regardless of whether it is an indoor product or an outdoor product,It can withstand the low temperature of 55°C specified by the product technical conditions, and it can be stored and transported at a temperature of 30°C
2)Humidity of indoor products
Degree: The relative humidity is not more than 95% per day, and the operation is frequent or
When the machine life and electrical life are approaching, the inspection period should be appropriate
When, the monthly average is not more than 90%; the saturated steam pressure daily is not high
At 0.0022MPa, the monthly average is smaller than 0. O018MPa.
- The degree of shock does not exceed 8 degrees
- Vacuum interrupter of vacuum circuit breaker In principle, it should be used in a vertical state.
- Not applicable to severe pollutionPlaces subject to contamination, chemical corrosion, and severe vibration.
3. Applications of vacuum circuit breaker
The vacuum circuit breaker is today recognized as the most reliable current interruption technology for medium voltage switchgear. It requires minimum maintenance compared to other circuit breaker technologies.
The technology is mainly suitable for mainly medium voltage applications and vacuum circuit breakers can been seen in various types of switchgears, such as metal-clad switchgear, air insulated switchgear,
4. Examples of vacuum circuit breakers used in switchgears
VS1 12kV vacuum circuit breaker installed in KYN28A-12 indoor metal-clad switchgear.
Zn85-40.5 vacuum circuit breaker installed in KYN61-40.5 switchgear.
VS1-24 24kV vacuum circuit breaker installed in XGN15-24 air insulated switchgear.
VS1-12 12kV vacuum circuit breaker installed in XGN15-12 air insulated switchgear.