The VEK-12 series single-chamber high-voltage vacuum circuit breaker is an indoor switching device designed for three-phase AC 50Hz systems with a rated voltage of 12kV. It is suitable for control and protection applications in industrial and mining enterprises, power plants, substations, and electrical facilities, and is well-suited for frequent operation scenarios. The breaker integrates a VET operating mechanism with the main unit, allowing it to be used either as a fixed installation unit or paired with a dedicated propulsion mechanism to form a withdrawable unit. The main circuit can utilize an integrated solid-sealed pole column to achieve compact size, high reliability, and maintenance-free operation. It is compatible with KYN28A-12 (GZS) and other withdrawable switchgear cabinets, as well as XGN fixed switchgear cabinets.