Vacuum Test of Vacuum Interrupter

The vacuum degree of the interrupter of the vacuum circuit breaker must be maintained within a certain limit, which is a necessary condition for reliable breaking. The degree of vacuum is expressed by the absolute pressure value of the gas, and the lower the absolute value, the higher the degree of vacuum. The circuit breaker with increased gas pressure inside the vacuum interrupter cannot interrupt the short-circuit current, or even the load current. Generally, the vacuum degree in the vacuum interrupter is kept between 10⁴Pa～10⁶Pa. According to national standards, for the vacuum circuit breaker in operation, the vacuum degree of the vacuum interrupter should not be greater than 6.6×10²Pa. When the vacuum degree is greater than this When the value is reached, the vacuum interrupter must be replaced. There are mainly the following two methods for testing the vacuum degree of the interrupter of the vacuum circuit breaker:

1.AC withstand voltage method

If the inside of the vacuum interrupter is at atmospheric pressure, as long as an AC voltage of 17～19kV is applied to it, the medium inside the vacuum interrupter will break down. Therefore, to determine whether a high degree of vacuum is maintained inside the interrupter, an AC 42kV withstand voltage test can be applied to the vacuum interrupter to check. If there is no high enough vacuum inside, it will be broken down almost without delay under this test voltage, so as long as it can last for 60 seconds under this test voltage, the vacuum degree of the vacuum interrupter is good.

2.Vacuum degree testing method

The vacuum tester is controlled by a microcomputer to automatically complete the entire test process. It can directly display the vacuum data, and the measurement range is 104Pa～101Pa. It is processed from the software design to filter out interference factors and improve the on-site anti-interference ability and measurement’s accuracy.

Through the test of the vacuum tester, the corresponding equipment account has been established, various test data have been recorded, and some experience data have been accumulated, which provides a powerful basis for mastering the operation status of the vacuum circuit breaker.