Vacuum circuit breakers have a large output and a wide range of applications in the field of medium voltage. According to statistics, in China's 40.5KV circuit breaker, vacuum circuit breaker has accounted for 84.31%, and in 12KV class, vacuum series has accounted for 99.39%.In 2009, China produced a total of 464,190 12KV vacuum circuit breakers, compared with 382123 in 2008, an increase of 82,067 units, a growth rate of 21.48%, especially in the 12KV level growth fast, such as 2004 vacuum series output of 238344 units, In 2009, there were 225846 more units than in 2004, and the number almost doubled in five years. There are a total of 148 manufacturers of 12KV vacuum circuit breakers in China.

With the sharp increase in the output of vacuum circuit breakers, the output of vacuum interrupters and manufacturers have also increased accordingly, in 2009, the output of 12KV vacuum interrupters reached 1337637, and the number of manufacturers reached 13, while in 2004, the output of 12KV vacuum interrupters was 799395. In the five years of 2004~2009, the output of vacuum interrupters has achieved a huge increase.

In foreign countries, medium-voltage vacuum circuit breakers also occupy an absolute advantage, such as Japan accounts for more than 90%, Germany accounts for more than 95%, and India also accounts for more than 89%. ABB at the end of the 90s of the last century, at the same time to promote vacuum and SF6 technology, and then vigorously develop vacuum technology, now the annual production of 350,000 vacuum interrupters, rated voltage to 40.5KV, rated short-circuit breaking current to 63KA. The solid sealing column technology is constantly improving, from the epoxy resin automatic pressure gel technology to the thermoplastic + short glass fiber spraying technology.

Medium-voltage vacuum circuit breakers have dominated the market, and there are three main reasons for this: First, the power sector promotes vacuum switches. In 1992, the electric power department began to promote vacuum switches to users, and after more than 10 years of efforts, manufacturers have accumulated rich operating experience, and vacuum switches are favored by users; Second, SF6 gas was designated as 6 restricted greenhouse gases by the Kyoto Protocol in 1997, although SF6 gas only contributes 0.1% to the greenhouse effect, but it is potentially dangerous, so it objectively promotes the development of vacuum circuit breakers; Third, the vacuum switch has made great progress in performance and reliability, which can meet the different needs of various users, and the development of various special and multi-functional vacuum circuit breaker products provides users with a lot of choice. At present, the column of the vacuum circuit breaker is transformed from air insulation, composite insulation, and solid seal insulation. The implementation of a sealing process in the manufacture of interrupters not only improves the output, but also improves the quality. From the perspective of contact structure, the development from transverse magnetic field to longitudinal magnetic field is greatly conducive to the improvement of breaking performance. The vacuum circuit breaker has also changed greatly in terms of function, from a single opening function to a multi-functional such as breaking-isolation grounding.

Based on the above reasons, vacuum circuit breakers have developed strongly in the field of medium voltage in China, with large output and many manufacturers, and are very popular with users.