Vacuum interrupter product research and development focus on four goals

According to the latest statistics, in 2002, the output of China's 12kV vacuum circuit breakers reached 133,519 units, accounting for 92.27% of the output of 12kV medium voltage circuit breakers. China has entered the ranks of vacuum circuit breakers including the United States, Germany and Japan. Among them, vacuum interrupter manufacturers have contributed.
At present, there are more than ten vacuum interrupter manufacturers in China, and the output can meet the needs of vacuum circuit breaker production. According to the 2002 sorting 12kV vacuum interrupter production, the three major manufacturers are Shaanxi Baoguang Vacuum Electric Co., Ltd. (128,163), China Zhenhua (Group) Technology Co., Ltd. Yuguang Branch (113,957) and Chengdu Xuguang Electronics. Co., Ltd. (72860). Therefore, for vacuum interrupter manufacturers, the problems they face in the future are not to increase production and compete with each other, but to innovate new products, increase varieties, improve quality, and constantly open up new markets.
At present, China's vacuum interrupter is mainly of the general type, while foreign countries have developed to a special type with higher functions. From the application point of view, China's vacuum interrupter is mainly used for vacuum circuit breakers, contactors and load switches, while foreign countries are expanding the use of vacuum interrupters. In addition to the above applications, they are also used for transformer on-load switches and power generation. The circuit breaker, the protection switch of the large-capacity test station, the switch that fits the superconducting coil during the thermonuclear polymerization test, and the contactor of the maglev train for the linear motor. Functionally speaking, the vacuum interrupter is no longer a single function to complete the split-combination function, but presents a multi-function. For example, the newly developed 24kV vacuum interrupter in Japan has to perform various functions such as split-separation-isolation-grounding.
According to the current development of vacuum interrupters, domestic manufacturers should strengthen R&D investment and focus on four objectives:
(1) High voltage type. Such as 72/84kV and 126kV vacuum interrupter. Fujifilm Japan has used its 72/84kV800/1200A25/31.kV vacuum interrupter for 72/84kV air-filled cabinets (C-GIS). If China can develop a 72.5kV single-break vacuum interrupter, it will lay the foundation for the development of 72.5kV outdoor vacuum circuit breakers and inflatable cabinets. In addition, China has developed a 126kV outdoor vacuum circuit breaker, while the arc extinguishing chamber is imported from Japan, which is not conducive to reducing the cost of the product, because the vacuum interrupter generally accounts for 40% to 45% of the vacuum circuit breaker cost. The higher the voltage level, the harder it is to make the vacuum interrupter, and the more expensive it is. China's existing vacuum interrupters are 12kV and 40.5kV, at 40.5kV, Xuguang Electronics Co., Ltd. produced 9457 in 2002, 6982 in the state-owned 777 factory, and 6252 in Baoguang. Zhenhua Company It is 2701. From the perspective of development, vacuum interrupter manufacturers should develop 72.5kV and 126kV single-break vacuum interrupters to meet the needs of vacuum circuit breakers to develop high voltage.
(2) Large current type. For example, the generator protection circuit breaker requires not only a large rated current (6300~12000A), but also a short-circuit breaking current (80~160kV). China can now achieve a 12kV short-circuit breaking current of 63kV, and further increase the capacity to meet the requirements of the generator's extra large capacity.
(3) Frequent operation type. For example, electric furnace steelmaking requires frequent operation of the circuit breaker. Siemens' 3AH4 vacuum circuit breakers are designed for frequent operation of electric furnaces with up to 120,000 operations. Toshiba has newly developed 24kV1250A/2000A20kV and 36kV1250A/2000A12.25kV special-purpose vacuum circuit breakers, increasing the number of operations from 100,000 to 150,000. There is still a big gap in domestic products in this regard.
(4) Low overvoltage type. A vacuum circuit breaker generates a dangerous overvoltage when the breaker is blocked or the motor is starting. The general solution to the overvoltage is to install an overvoltage absorbing device, such as SiC, RC loop, ZnO arrester, etc. The latest practice is to develop low overvoltage contact materials and no overvoltage absorbing devices. Several Japanese companies have succeeded in this area, each developing low overvoltage contact materials. For example, Hitachi's silver-based Co-Ag-Se contact material, Toshiba's Ag-WC contact material, Fuji's CuCr+ high-vapor material, and Mitsubishi's Cu-Cr-Bi-a multi-contact material. Due to the contradiction between low overvoltage and high current breaking, the low overvoltage vacuum circuit breaker generally achieves a level of 7.2kV20kA, but Toshiba has made a breakthrough to achieve a level of 7.2kV40kA.
The low overvoltage contact material can reduce the overvoltage to a conventional 1/10, which is obvious. Therefore, China should step up the development of low overvoltage contact materials, prompting the early introduction of low overvoltage vacuum circuit breakers.