Progress in High Voltage Vacuum Circuit Breaker Technology

2024-10-23 00:16:55

Outdoor high-voltage Vacuum Circuit Breakers (column mounted vacuum Circuit breakers) have an absolute advantage in the medium voltage field (12-40.5kV), and have also temporarily emerged in the high-voltage field (72.5-252kV), with promising development prospects. In China, medium voltage vacuum circuit breakers accounted for 99.39% of medium voltage switches in 2009. New products of high-voltage vacuum circuit breakers have been continuously developed and put into operation at the 72.5-126kV level. In foreign countries, many countries and companies are developing high-voltage vacuum circuit breakers, and some products have been in operation for many years, such as Japan, South Korea, the United States, Germany, Russia, etc. According to statistics, the Japanese power transmission system has used 3350 units of 72-252kV vacuum circuit breakers. At present, high-voltage vacuum circuit breakers have reached 145kV single break and 168kV double break, and higher voltage level products are currently being developed. The product has both tank type and porcelain column type structures. China has already produced porcelain column type 126kV high-voltage vacuum circuit breakers, while Japan's 168kV vacuum circuit breakers adopt tank type structures. On the insulation outside the vacuum arc extinguishing chamber, low-pressure SF6 gas (with an internal filling pressure of 0.12MPa) is used for insulation, and dry pressure air is also used for external insulation.

It is worth mentioning that two mainstream manufacturers of high-voltage switches in China have newly developed porcelain column vacuum circuit breakers, such as the 126kV vacuum circuit breaker successfully completed by Xidian Company in 2010 and passed the acceptance of the Ministry of Science and Technology. The arc extinguishing chamber of this product adopts a longitudinal magnetic field coil structure and uses copper chromium contact materials with high breaking capacity and good resistance to welding. The vacuum arc extinguishing chamber developed for this project is the first domestically developed product with intellectual property rights, and its technical level is at a high level. Another company is Pinggao Group. While vigorously developing high-voltage and high-capacity SF6 circuit breakers, Pinggao Group also seized the opportunity to develop high-voltage vacuum circuit breakers. The group conducted national appraisal of four new products, namely LW55-72.5 tank SF6 circuit breaker, ZW55-63 high-voltage vacuum circuit breaker, ZW55-2 × 31.5 and ZW55-31.5 vacuum circuit breaker, in November 2011, and overall achieved the standard.

At the 2011 Hanover Fair, Siemens showcased a 72.5kV vacuum circuit breaker insulated with nitrogen (N2) instead of traditional SF6 circuit breakers, indicating that Siemens began to focus on the research and development of outdoor high-voltage vacuum circuit breakers. At high voltage levels, the development of vacuum circuit breakers is necessary for the development of the situation, which can greatly reduce the use of SF6 greenhouse gas, promote environmental protection, and reduce greenhouse effects in the atmosphere. At the same time, high-voltage vacuum circuit breakers have good low-temperature resistance characteristics, which can avoid the problem of SF6 gas liquefaction in high-altitude areas and are a good choice for high-voltage circuit breakers in high-altitude areas. In the development of high-voltage vacuum circuit breakers, a series of technical problems need to be solved, including high-voltage vacuum insulation, high current vacuum breaking, rated current and temperature rise, mechanical characteristics, insulation and capacitive current breaking outside the vacuum arc extinguishing chamber, and small inductive current breaking. The resolution of these technical issues has promoted the advancement of vacuum circuit breaker technology. However, the development of outdoor high-voltage vacuum circuit breakers is still in its infancy and requires vigorous research work.