"High-voltage vacuum circuit breaker" is named because its arc extinguishing medium and the insulating medium in the contact gap after arc extinguishing are high vacuum. It has the advantages of small size, light weight, suitable for frequent operation, and can extinguish fire without maintenance, and is widely used in distribution networks. A brief history of development 1893, Rittenhouse, USA, proposed a vacuum interrupter with simple structure and obtained a patent for its design. 1920, Swedish Foga company made the vacuum switch for the first time. The research results published in 1926 also show the possibility of interrupting current in vacuum, but it can not be put into practical use because of its small interrupting ability and limited by the development level of vacuum technology and vacuum materials. With the development of vacuum technology, the United States made the first batch of vacuum switches suitable for cutting off capacitor banks and other special requirements in the 1950s, and the breaking current was still at the level of 4 kA. Due to the progress of vacuum material smelting technology and the breakthrough of vacuum switch contact structure research, 196 1 year, vacuum circuit breakers with 15 kV and breaking current 12.5 kA were started to be produced. 15kV, 26kA, 3 1.5kA vacuum circuit breakers were successfully trial-produced in 1966, which enabled the vacuum circuit breakers to enter the power system with high voltage and large capacity. In the mid-1980s, the breaking capacity of vacuum circuit breakers has reached 100 kA. China started to develop vacuum switches from 1958. 1960, Xi jiaotong university and Xi' an switch rectifier factory developed the first batch of vacuum switches with 6.7 kV and 600 A breaking capacity. Then a three-phase vacuum switch with 65438±00kV and breaking capacity of 65438±0.5 kA was made. 1969 huaguang electron tube factory and Xi' an high-voltage electric apparatus research institute manufactured 10 kV and 2 kA single-phase fast vacuum switch. Since 1970s, China has been able to independently develop and produce vacuum switches of various specifications. Vacuum circuit breakers can usually be divided into multiple voltage levels. Low-voltage type is generally used for explosion-proof electrical use. Like coal mines and so on.
Distribution transformer is one of the important equipment in the power supply and distribution system of industrial and mining enterprises and civil buildings, which reduces the grid voltage of 10(6)kV or 35kV to 230/400V? Bus voltage. These products are suitable for AC 50(60)Hz, and the maximum rated capacity of three-phase is 2500kVA (the maximum rated capacity of single-phase is 833kVA, so it is generally not recommended to use single-phase transformers). It can be used indoors (outdoors), with a capacity of 3 15kVA and below, and can be installed on poles when the ambient temperature is not higher than 40℃ and not lower than -25℃, with the highest daily average. If the above conditions are not met, appropriate quota adjustment shall be made according to the relevant provisions of GB6450-86.