KYN28A-12 armored open-type AC metal switchgear, rated voltage 12kV, is a three-phase AC 50Hz single-bus sectionalized system or double-bus sectionalized system of indoor power distribution equipment. It is used for receiving and distributing 3.6-12kV network power, and practicing control and protection, monitoring and measurement of power circuits. The center-mounted switchgear is mainly used for power plants, power transmission of small and medium-sized generators, receiving and transmitting power in secondary substations of power systems, power distribution of industrial, mining, enterprises and public institutions, as well as starting of large-scale high-voltage motors, etc., to realize the functions of control, protection and detection.

　　The performance of this switchgear meets the requirements of GB3906, IEC298 and other standards, and it has the functions of preventing from pushing and pulling the circuit breaker trolley with load, preventing from mistakenly separating and closing the circuit breaker, preventing from closing the circuit breaker when the earthing switch is in the closing position, preventing from mistakenly entering into the electrically-charged compartment, and preventing from mistakenly closing the earthing switch when it is electrically-charged, and it is a kind of power distribution device with superior performance.