Introduction of Vacuum circuit breaker
“Vacuum Circuit Breaker” gets its name because its arc extinguishing medium and the insulation medium of the contact gap after arc extinguishing are both high vacuum; it has the advantages of small size, light weight, suitable for frequent operation, and no maintenance for arc extinguishing. Applications in the power grid are relatively widespread. High voltage vacuum circuit breaker is an indoor power distribution device in a 3 ～ 10kV, 50Hz three-phase AC system. It can be used for the protection and control of electrical equipment in industrial and mining enterprises, power plants, and substations. For maintenance and frequent use, the circuit breaker can be configured in the center cabinet, double-layer cabinet and fixed cabinet for controlling and protecting high-voltage electrical equipment.
The history of Vacuum circuit breaker
In 1893, Rittenhouse in the United States proposed a vacuum interrupter with a simple structure and obtained a design patent. In 1920, the Swedish Foga Company made the first vacuum switch. Research results published in 1926 and others also show the possibility of breaking the current in a vacuum. However, due to the small breaking capacity and the limitation of the development level of vacuum technology and vacuum materials, it has not been put into practical use. With the development of vacuum technology, in the 1950s, the United States only made the first batch of vacuum switches suitable for cutting off capacitor banks and other special requirements. The breaking current is still at the level of 4 thousand amps. Due to advances in vacuum material smelting technology and breakthroughs in the research of vacuum switch contact structures, in 1961, production of vacuum circuit breakers with a voltage of 15 kV and a breaking current of 12.5 kA began. In 1966, 15 kV, 26 kA, and 31.5 kA vacuum circuit breakers were trial-manufactured, so that the vacuum circuit breaker entered a high-voltage, large-capacity power system. In the mid-1980s, the breaking capacity of vacuum circuit breakers reached 100 kA. China began to develop vacuum switches in 1958. In 1960, Xi’an Jiaotong University and Xi’an Switch Rectifier Factory jointly developed the first batch of 6.7 kV vacuum switches with a breaking capacity of 600 A. Subsequently, they were made into 10 kV and a breaking capacity of 1.5. Qian’an three-phase vacuum switch. In 1969, Huaguang Electron Tube Factory and Xi’an High Voltage Apparatus Research Institute produced a 10 kV, 2 kA single-phase fast vacuum switch. Since the 1970s, China has been able to independently develop and produce vacuum switches of various specifications.
The specification of Vacuum circuit breaker
Vacuum circuit breakers are usually divided into multiple voltage levels. Low voltage type is generally used for explosion-proof electrical use. Like coal mines and so on.
The rated current reaches 5000A, the breaking current reaches a better level of 50kA, and has developed to a voltage of 35kV.
Before the 1980s, vacuum circuit breakers were in the initial stage of development, and they were constantly exploring the technology. It was not possible to formulate technical standards. It was not until 1985 that relevant product standards were made.