Regarding the selection conditions of vacuum circuit breakers, the selection of vacuum circuit breakers should be considered from several aspects, including frequent operation places, preferably “integrated” structure, 10kV voltage level is preferably vacuum circuit breaker, the selected vacuum circuit breaker should meet the standard, etc. .

For the selection of vacuum circuit breakers, consider the following aspects:

1. Frequent operating places.

Priority should be given to vacuum circuit breakers, such as switching capacitor banks, controlling high-voltage motors, controlling and protecting electric furnace transformers, and electric trains.

2. The “integrated” structure is preferred.

When the operating conditions and operating environment are met, the “integrated” structure should be preferred, and the “split” structure should be avoided as much as possible.

3. Vacuum circuit breaker is preferred for 10kV voltage level.

Taking into account the requirements of reducing operation and maintenance costs, noise, fire prevention and miniaturization, vacuum circuit breakers should be given priority in the 10kV voltage level power supply system.

4. The selected vacuum circuit breaker should meet the standard.

The selected vacuum circuit breaker should comply with DL/T 402-2007 “Technical Conditions for Ordering High Voltage AC Circuit Breakers” and DL/T 403-2000 “Ordering Technical Conditions for 12kV-40. 5kV High Voltage Vacuum Circuit Breakers” and other standards. The electrical and mechanical performance requirements are mainly:

1) After the short-circuit current is cut off, the insulation withstand voltage level should not be reduced.

2) When it meets the inductive load, it should be able to withstand the current carrying overvoltage.

3) When used in a non-effective grounding system, it should be subjected to an out-of-phase grounding fault breaking test first.

4) The closing bounce time is not more than 2ms, and the opening bounce amplitude and the no-current interval time of automatic reclosing should meet the product technical conditions.

5) It should have sufficient mechanical life (generally 10000 times) and electrical life (10000 times when the rated current is cut off, and 20-50 times when the rated short-circuit current is cut off).

Whether under-voltage protection is needed or not can be determined according to the requirements of use.