The vacuum degree test of the vacuum circuit breaker is very important. Once the vacuum degree is destroyed, the arc cannot be extinguished, resulting in an explosion accident of the circuit breaker. The vacuum inspection test methods are as follows:
If the vacuum interrupter is a glass shell, it can be judged according to the color of the barium getter film coated on the inner wall. If the vacuum degree is good, the film is in a mirror state. When the vacuum degree of the vacuum circuit breakers is poor, it is milky white. This method is not very accurate, but it is worth having a check as a reference.
In the open state, the frequency test voltage is processed between the fractures, and the vacuum circuit breakers can withstand more than 60s under the power frequency withstand voltage, indicating that the vacuum degree of the vacuum circuit breaker is good. If in the process of voltage increase, the current also increases to over 5A, then it is considered to unqualified. Of course, the breakdown in the process of withstand voltage is not qualified. Choose 33kv auto recloser, 11kv auto recloser and 24kv vacuum circuit breaker.
Use a special testing instrument to measure, add one or several high-voltage pulses between the contacts, the pulse width is tens to hundreds of milliseconds, and a synchronous pulse current is passed through the magnetic field coil to generate the same pulsed magnetic field as the high-voltage and vacuum measurement. Relevant national rules stipulate that the vacuum degree reaches 0.066Pa as qualified, and when it is close to or lower than 0.6, it is unqualified and should be updated. When the vacuum degree drops significantly and fails to pass, the test cycle should be shortened, and whether to update or not should be decided according to the development situation.
At present, due to the development of science and technology, various types of complete sets of measuring instruments have been manufactured for automatic circuit reclosers, and quantitative measurement without disassembly on site has been realized. With the means of quantitative measurement, it is not only possible to measure whether the vacuum degree of the vacuum switch is within the normal range, but more importantly, for some vacuum switches with a faster leakage rate, by comparing the measurement results over the years, it can be roughly inferred. , the real purpose of preventing accidents.
Zhuhai Gopower Smart Grid Co., LTD is a vacuum circuit breaker manufacturer in China, our products cover feeder terminal unit (FTU), station terminal (DTU), transformer terminal unit (TTU), column switch, fault indicator and background master station in 10kV distribution network lines software. And long-term cooperation with well-known domestic and foreign companies such as ABB, Gaoping Group, Daye Intelligence, TBEA, Shandong Electric, etc. We serve for State Grid Corporation, China Southern Power Grid Corporation and overseas markets.