With the continuous development of society and the economy, and the increasing complexity of engineering construction, users have higher and higher requirements for the miniaturization, maintenance-free operation, and intelligence of switchgear. In the medium-voltage field, especially at the 35kV voltage level, conventional air-insulated switchgear is generally large in size (width not less than 1200mm, volume generally not less than 7m²), heavy (generally not less than 2t), and difficult to operate, especially unable to meet the requirements for use in harsh environments such as high altitude, humidity, and pollution. Against this backdrop, C-GIS (Cubicle Gas-Insulated Switchgear) is attracting increasing attention.
C-GIS is an extension of high-voltage GIS products into the medium-voltage field. It is a high-tech product that uses low-pressure SF6 gas, N2 gas, or a mixture of gases as the insulating medium for switchgear, and vacuum or SF6 as the arc-extinguishing medium. It encloses medium-voltage components such as busbars, circuit breakers, and disconnectors in a sealed enclosure. It integrates intelligent control, protection, monitoring, measurement, and communication technologies, utilizing modern insulation, breaking, manufacturing, sensing, and digital technologies. It boasts advantages such as small size, light weight, high safety, high reliability, and adaptability to harsh environmental conditions.
The reason for using GIS is that in high-voltage systems, the use of disconnecting components requires a large distance between each phase. However, hydropower stations are often located in mountainous areas where large areas of flat land are difficult to find. GIS, with its small size, effectively solves this problem.